Full text of "Papers presented at the Celebration of the Twentieth Anniversary of the New York Botanical Garden, September 6-9, 1915. Published by the aid of the David Lydig Fund, bequethed by Charles P. Daly"

See other formats

wae 29

“uy

= bb

iP pe :
‘dh ba ® me

ets t

fy
ray Sa ee |
La .
yy ooh,
aa Nara vgs “98
a? wy
* her 4.
Lt v
+ lie
. :
. ‘
‘
S
~
s 5
’
‘ é
- ¥
§ 9
b a“ 7s
eT
* ‘c¥ *\
very
AR
ve! ae
v * 4
" ‘ .
¥
.
i (
¢ * ‘ :
A
a >
iy
»
i
=
de a

MEMOIRS

OF THE

NEW YORK BOTANICAL GARDEN
J VoL. VI

PAPERS

PRESENTED AT THE

Celebration of the Twentieth Anniversary

The New York Botanical Garden

September 6-9, 1015

ISSUBD AUGUST 81, 1916

-
s
7
i wy
~~ q
vy a
re >!
Lana '
*
Rey isn 4
=
}

are
=
&
»
,
:
a
*

“a
7

+ +

y
*

*«

ves

PL?

>
(
i
ie
of
7
. - e
,
‘LA
{ may
F
a"
¢
F
:

ain =-

«
z
pw eet
’
5 }
.
1h
be -
2
e
ee)
*
bg +
. .
4

y
.

jeer: _*
a ie eat

it ee
” Be

PAPERS

PRESENTED AT THE

Celebration of the Twentieth Anniversary

The New York Botanical Garden

September 6-9, 1915

PUBLISHED BY THE AID OF THE

DAVID LYDIG FUND

BEQUEATHED BY CHARLES P. DALY

NEW YORK
1916

> ~
re
~ = ay
re
+ a
~ we _ 7
~ 1 i
: ~ i, ‘ee »
nesta
Pe >
. —f..
te ~ fr, ik ra
\ - ¥
? ’
. ae
: ~ el ‘
7 a ~ am
4 ele ae
—- a.
== g P-
° +

HE NEW ERA PRINTING COMPANY

LANCASTER, PA,

PREFACE

The papers herewith published are arranged essentially in the
order of their presentation as indicated in the general account of
the Twentieth Anniversary Celebration published in the Journal of
The New York Botanical Garden for October, 1915. Three of
the papers presented are here omitted for the reason that they
have been, in substance, already published elsewhere in accordance
with prior engagements. “ Collybia in North America,”’ by W. A.
Murrill, was essentially a summary, along statistical and geo-
graphic lines, of the monograph of the genus Gymnopus (Collybia)
which subsequently appeared in the North American Flora
(9: 352-374. 7 Je 1916). The main facts of the paper by R. S.
Williams on “‘ Philippine Island mosses collected by J. B. Leiberg’’
are to be found in a paper entitled ‘‘ Mosses of the Philippine and
Hawaiian Islands collected by the late John B. Leiberg,” published
in the Bulletin of the Torrey Botanical Club (42: 571-577. 1.23 N
1915). Likewise, the substance of the paper by B. O. Dodge on
the “Influence of the host on the morphology of the roestelia,”’
appeared in the Bulletin of the Torrey Botanical Club (42: 519-
542. pl. 28, 29. 5 N 1915) under the title, ‘‘The effect of the
host on the morphology of certain species of Gymnosporangium.”’
Six other papers actually read are omitted because of obligations
to publish elsewhere, or because they were considered by their
authors to be too incomplete or preliminary to justify publication
at the present time, or for other reasons. Of the papers read by
title, only one (that by W. J. Beal) is included in the present

volume.
MARSHALL A. Howe,

Editor

CONTENTS

THomeson, W. GILMAN. Address of welcome..................
MacDoucaL, D. T. The mechanism and conditions of growth
SLIEAL Jeu 220-2 Ga Bea eet ok a oes 2h Ne on SOP a
Tuompson, W. P., and BaiLey, I. W. Are Tetracentron, Trocho-
dendron, and Drimys specialized or primitive types? (with
(CIES e7 elt oe ern b io fh Ot cee ei a ri. Wace set
CHIVERS, ARTHUR H. Directing factors in the teaching of botany. .
BARNHART, JOHN HENDLEY. Segregation of genera in Lentibu-
FIBA CAC Rad Pe seins ah edes) Aint eke Qbavres eke Fig Sar hye ee
CALL, RICHARD ELLSWORTH: Observations on the flora of Mam-
Paes AVON Neti CUCKy Anas sl a ee ee sew SUS as gee eee
YAMPOLSKY, CECIL. Observations on inheritance of sex-ratios in
NAGLE ERISA TEE. aD a eT eA a oe LY CEE A arn ee
HuMpHREYs, Epwin W. Triassic p!ants from Sonora, Mexico, in-
cluding a WNeocalamites not previously reported from North
Pee rica a witha DIAEE SO sgt ae ees ee eRe ee he) Sener
TAyLor, NORMAN. A white-cedar swamp at Merrick, Long Island,
and tts. sisniticance (with plates 6-10)" 7,8 3.be. 2222
BLAKESLEE, ALBERT F. Inheritable variations in the yellow daisy
CRIMLOLORLOONIT ID) ©. p rahe). ay Ae OER tone vidaees eke ae ees
Harper, R. A. On the nature of types in Pediastrum...........
Howe, MArsHALL AvERY, and Hoyt, WILLIAM Dana. Notes on
some marine algae from the vicinity of Beaufort, North Carolina
(uci le jel eR eS 6 is ep eae a ar 20 ov
LEVINE, MICHAEL. Somatic and reduction divisions in certain
srectessol Drosera (with plates 16-16)\\-. 2.64 25...) as ies»
SHAW, Harry B. Self, close and cross fertilization of beets (with
[RSIS 1) 4 SE ah ne A ected YE je RS ast Ete eae
GaGER, C. Stuart. Present status of the problem of the effect of
famvenmecyesOu plant tile). 6... re see ac od One bc eh ae
SINNOTT, EpMuND W. Endemism as a criterion of antiquity among
JO ETDES oa Dc AC UpRNARRRAS DCC 8) FRR ARS" ( e Seee an ea
GRAVES, ArTHUR H. A botanical trip to North Wales in June....
Orton, C. R. North American species of Allodus...............
ATKINSON, GEO. F. The development of Lepiota cristata and
Ue SCHMU UAE Cwm PIALeS, 21—96)iM so boa ahs eae ee oe
Harris, J. ARTHUR. A tetracotyledonous race of Phaseolus vulgaris.
vill

27
33

39
65

75
79

89
gr

Vili MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

KERN, FRANK D. Japanese species of Gymnosporangium......... 245
Farr, CLIFFORD HARRISON. Cytokinesis of the pollen-mother-cells

of certain dicotyledons (with plates 27-29)................... 253
LipMAN, CHAs. B. Plant ecology and the new soil fertility. ...... 319

GRAVES, ARTHUR H. Chemotropic reactions in Rhizopus nigricans. 323
Stout, A. B. Self- and cross-pollinations in Cichorium Intybus

with reference to sterility (with plate 30).................... 333
Norton, J..B.S.° Variation in’ Tiiymalopsts... 0.0 na ae 455
FARWELL, OLIVER ATKINS. The genus Hippochaete in North

America, north: of -Mexicas.5 a8 ices + ee eee 461
Hotiick, ArtHuR. A fossil fern monstrosity (with plates 31, 32). .473
“SMALL, JOHN K. Recent exploration in southern Florida......... 475
RypsBerG, P. A. Vegetative life zones of the Rocky Mountain

YORAM econ so: of ses 5 Fe sce eee can ep a tn ae 477
SEAVER,’ FRED: J.«..Bermuda. fumgiic).4. +e yo. ee ee ae 501

BEAL, W. J. Some things learned in managing a botanic garden.. 513
KELLERMAN, KARL F. Cooperation in the investigation and control

of plant diseases. ..i hn. nln ie eee oe ee 517
BLACK, CAROLINE A. The nature of the inflorescence and fruit of
Pyrus Malus (with plates.33-40) .!.o42 5 20eul se ce ee 519

TAUBENHAUS, J. J. A contribution to our knowledge of silver
scurf (Spondylocladium atrovirens Harz) of the white potato

(with plates 41-43) 0.) .4...s.08 hp RE a teens eee 549
Lioyp, Francis E. The embryo-sac and pollen grain as colloidal
SYSTEMS... 5h. p scars ase soe a) eee acts eee oe 561

Britton, N. L. The vegetation of Anegada:.....1..... 2A eee 565

ADDRESS OF WELCOME

W. GILMAN THOMPSON

President, Board of Managers, The New York Botanical Garden

Ladies and Gentlemen:

On behalf of the Board of Managers of The New York Botanical
Garden, I extend to you a most cordial welcome to the celebration
of the twentieth anniversary of the establishment of the Garden.
The attendance here of so many guests, representatives of dis-
tinguished scientific and educational organizations in many parts
of the country, is in itself a gratifying reward for the labor and
study expended in the development of the Garden, and will
doubtless bring the stimulus of great encouragement to the energies
of its Staff. In these troublous times, when so large a part of the
world seems bent upon its own mad destruction, it is wholesome
to turn to constructive processes, and to a peaceful science based
upon the phenomena of growth.

As a matter of local interest, too, it is interesting that in the
midst of a great city characterized particularly by the hurry and
bustle of strife (not to say by noise!) there should be found a
garden of beauty and peace, where one may commune with a
lotus from the Ganges, an orchid from the scenes of the Amazon,
or a pine from a far-off Himalayan mountainside. During the
past score of years, nothing of greater importance has occurred
in the phenomenal expansion of the City than the rescue and
redemption of the Garden land, so that, including a recent acquisi-
tion, there are now nearly 400 acres constituting a permanent
garden and lying within what has become a prominent residential
center of Greater New York.

If our eminent Director could have been called as consulting
botanist in paleozoic days, I doubt whether he could have sug-
gested a more ideal site for a botanical garden than that which
nature kindly offered to the Board of Managers twenty years ago,

2 I

2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

with its river and falls and ponds, its ravine and marshes and
swales and twenty acres of hemlock forest, affording scenes as
wild and picturesque, almost, as the Adirondacks.

But it is not natural beauty alone which we celebrate here, for
during its comparatively short life the Garden has won equal
rank as one of a quartette of educational and scientific institutions
established through private munificence in cooperation with the
City’s funds for construction and maintenance—the other three
being the American Museum of Natural History, the Metro-
politan Museum of Art, and the Zoological Park. Like these
kindred institutions, the Garden, in addition to the educational
facilities offered to specialists and to the general public, affords
opportunities for instruction through lectures, demonstrations,
and excursions through its grounds, museum, and greenhouses
to public school teachers and tens of thousands of school children.
Like these institutions also, it reaches out to other countries all
over the world and upwards of a hundred expeditions have been
sent out in this country and abroad to gather material for its
collections and research. The constantly increasing number of
those whose generosity has led to the contribution of valuable
collections or of funds for special collections or expeditions is a
source of great gratification to the Managers, indicating as it
does, substantial appreciation of the aims which it-has been their
endeavor to accomplish.

The work of a great botanic garden is far wider than the mere
maintenance of a store-house for collections. In addition, it
comes under three divisions, that of research in pure science for
the advancement of botanical knowledge, second, that of edu-
cation of all classes of the community, from school children up-
ward, and finally there is the aesthetic field, which, like that of a
museum of art, should not alone afford gratification to the love
of beauty and form, but which should be suggestive for imitation
elsewhere. In other words, the general effects of form and color
to be derived from appropriate grouping or mass planting may
be produced upon a large scale, combined with reference to
environment, seasonal conditions, etc. This latter phase of the
Garden’s work has been left, in great part, until now, but the
140 acres of additional land lately secured, suggests its prac-
ticability and a special fund is being raised for its accomplishment.

THOMPSON: ADDRESS OF WELCOME 3

The Garden, it should be remembered, was begun by the redemp-
tion, twenty years ago, of what was literally a goat pasture and
the recedence of that valuable domestic animal awas necessarily
followed for several years by gradual substitution of his custo-
mary articles of diet by a more varied flora. The early work of
the Garden, concerned as it was with the construction of new
buildings, grading, planting, and road-making, could not be expected
to include at once all those features of adornment which should
be the outcome of prolonged study. Moreover, within the period
of years which we are celebrating, there has been a remarkable
development of intelligent interest in private gardens, whose
owners constantly are seeking practical’ illustrations as guides
for their own work. Two decades ago how few reliable books
existed upon aesthetic gardening, compared with the numerous
practical treatises obtainable today! Garden clubs are springing
up like mushrooms (although, let us hope, with more substantial
basis!), and the florists are offering a range of selection in variety
and form and color of garden plants quite unimagined twenty
years ago. There is, therefore, an opportunity for a botanical
garden to furnish object lessons in planting, in grouping and
outdoor arrangement of flowers which may serve as public stand-
ards, just as art museums furnish standards for art. A very
useful and popular innovation has been introduced here in the
spring and autumn inspections of the grounds to which the public
are especially invited, which consists of practical demonstrations
by the gardeners of the processes of planting and transplanting.

Of the purely scientific achievements of the Garden during the
past twenty years, a layman may not presume to speak before an
audience so proficient in botanical lore, but the Managers are
most appreciative of the earnestness and devotion to their work
of the entire Garden Scientific Staff. I cannot conclude these
remarks, however, without expressing the feeling that this cele-
bration of the Garden is in reality a celebration of its Director-
in-Chief. His scientific attainments are well known to you all,
but his untiring energy, admirable judgment, and genius for
organization can only fully be appreciated by those of us who
have worked in codperation with him for the past twenty years,
and who have learned to regard the Garden and “ Britton”’ as syn-
onymous botanical terms!

4 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

A glance at the list of scientific papers to be presented by our
guests at this anniversary celebration bespeaks their appreciation
and good will, as it also constitutes a notable event in the botanical
history of this country.

Once more I bid you cordially welcome, and in the phraseology
of those unique gardeners, the Japanese, ‘‘the honorable Garden
is yours.”

THE MECHANISM AND CONDITIONS OF GROWTH

D. T. MacDouGAL

Carnegie Institution of Washington
(WITH PLATE I)

One of the most important characteristics of the activities of
living matter is that external substances pass into it more or less
constantly, thus adding to its bulk, and the introduced material
is ultimately partly burned and its energy rendered available,
while some of it is converted into constituents of the colloidal
protoplast and its envelope, increasing their mass, the accretion
being followed by changes in arrangement and structure which
find external expression in alterations in form and size. Such
increases are accompanied and made possible mechanically by
differentiations into tissues or specialized tracts.

The general external features of growth are of the most obvious
kind. When, however, we set ourselves the task of determining
the conditions under which it proceeds, of analyzing the contribu-
tory factors, and of measuring their relative influence on its rate
and course, technical difficulties of a very refractory kind are
encountered. The elements and their compounds necessary for
growth are in the main known to us, and also the fact that water
is of an importance in the process corresponding to its high pro-
portion in protoplasm.

The purpose of the present paper is not to discuss these
features of the matter, but rather to present the results of some
experimentation which seems to have important bearing upon
the main problems of growth. In any picture we may draw
of the irreversible accretions to living matter and its accessory
and enveloping structures, attention may well be centered upon
the origination of the material to be used. The greater amount
of growth is accomplished in the higher plants by material which
has accumulated in storage tracts or is being formed by photo-
synthesis or otherwise, and this material must be diffused a

6 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

distance varying from that of a fraction of the radius of a cell to
many meters to the protoplasts which are to make use of it. The
origination or the hydrolyzation of this material is a chemical
process, and the rate or velocity at which it takes place is one
which may be assumed to bear the relation to temperature by
which it doubles or accelerates even faster for every rise of 10
degrees C.

Diffusion is much less affected by temperature, hence the rate
and amount of translocation is much less affected by temperature.
When the dissolved food reaches the membrane or the periphery
of a protoplast it is then in a position of being about to become
part of the integral substance of bodies of widely different compo-
sition, and it must therefore be taken for granted that for the
growth of different organs, tissues, or protoplastic members, the
food-material must be converted into ‘building material.”’

This building material must. be of a highly specific character,
and that such special stuffs are formed in the growth and develop-
ment of the complex plant is the conclusion to which all morpho-
genic experiments converge during the last decade. Non-develop-
ment under conditions inhibiting the construction of ‘‘formative
stuffs” is now well exemplified by a score of investigations, the
latest available results being those of my own in which the form
of the polymorphous leaf of Neobeckia might be attributed to
special materials.!. The induction or inhibition of flower forma-
tion, fruit-development, tuberization, spore-formation, conjuga-
tion, etc.,in plants from the algae to the Compositae by variation
of external conditions is a matter of the commonest observation
and in every analyzed instance has yielded the single conclusion
that such action is through the formation or lack of formation of
special building materials.

The initiatory stage of the supplying of food to a growing part
of a plant may or may not be a chemical change, the second link
is one of diffusion or osmosis, and the third must inevitably be
one of chemical change as a consequence of which temperature
plays the dominating rdle, affecting not only the rate at which
such changes take place, but also to a lesser extent the perme-
ability of membranes and the’ hydratation capacity of the colloids

1 MacDougal, D. T. The determinative action of environic factors upon Neobeckia
aquatica Greene. Flora 106: 265-280. 1914.

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 7

concerned. No other single agency or external force acting
upon an adequate food-supply may exert so wide a range of
effects, upon the processes necessary in the adduction and forma-
tion of building material necessary for growth.

In the incorporation of this material, however, some energetics
are involved in which light also may play a part. Turgidity and
its resultant pressure-effects, hydratation capacity and its re-
sultant swelling in the cell colloids, while modified by temperature,
are also highly respondent to the acidity and alkalinity of the
solutions which penetrate them, in consequence of which light,
as will be shown later, may play a more important réle than in
other phases of growth. This form of energy, especially in the
shorter wave lengths, may neutralize or coagulate protoplastic
colloids, especially in the minute plants and it is probable that the
efficiency of this agency in sterilization is because of this action.
Its partial action would decrease hydratation capacity and thus
tend to lessen growth.

The author carried out some extensive experiments upon the
course of growth and development of plants in darkness, previous
to 1904, and in connection with this study of the features of
enlargement and differentiation of shoots uninfluenced by growth
obtained some insight into the positive effects of light on growth.
The results of this work carried on at The New York Botanical
Garden, 1899-1904, showed that the total amount of growth
accomplished by individual plants of a hundred species selected
for the experiments might be more or less in any given dimension
in darkness than in light, that the rate of growth might be af-
fected in a similar manner and. that the effect of light on growth
was not invariable. This rendered unsafe at once the trite con-
clusion that ‘‘light retards growth,” current from the time of Sachs
to the present day and still repeated in text-books and lectures.

My own results! on the matter were presented only in a gener-
alized way, and their validity was not considered by authors of
text-books and reviewers, including Barnes, Jost, and others.

Blaauw,? a Dutch investigator, has recently studied the question

MacDougal, D. T. Influence of light and darkness on growth and development.
Mem. N. Y. Bot. Garden 2: 307, 308. 1903. Also, Light and the rate of growth in
plants. Science II. 41: 467-469. 1915.

? Blaauw, A. H. Licht und Wachstum. Zeitsch. Bot. 6: 641-703. 1914. Also,
7: 465-532. 1915.

8 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

anew, and his fortunate choice of material in the delicate spo-
rangiophores of Phycomyces, and the availability of apparatus for
temperature regulation, and of measurable sources of light made
it possible to secure data upon which some conclusions as to
beginning and following effects of illumination on growth, and
the influence of exposures of varying length and to a series of
intensities might be reached. Later, similar studies were made of
Helianthus globosus. The behavior of the two plants included some
striking dissimilarities. The illumination of Phycomyces results in
an immediate acceleration, while in Helianthus the primary effect
is a retardation. The course of growth in Phycomyces includes a
primary acceleration, then retardation with a final rising rate.
Helianthus is first checked, then shows an acceleration, which
slackens gradually to the original course.

Vogt! has also made some measurements of the growth of the
coleoptile of Avena sativa, well controlled as to temperature and
light, in which it was found that the illumination of a plant (not
etiolated) is soon followed by an acceleration of growth, the
duration of which depends upon the intensity of the light. The
rate now falls off for a period, then rises to or above the normal.

If these be taken in connection with my own findings of the
behavior of a plant deprived of illumination, viz: “In one series,
however, the peduncles and scapes of Arisaema nearing the end
of their period of elongation showed an initial acceleration when
light was totally excluded from the plants. This acceleration
reached its maximum in twenty-four hours then decreased to a
minimum equivalent to the original rate in about four times this
period,’’ adequate ground will be found for the conclusion that
the reaction of plants in growth to light is due directly or indirectly
to physico-chemical changes effected by light-energy.

Opportunity for reconsideration of the general problems of
growth developed at the Desert Laboratory two years ago and a
series of experimental observations was planned to make an
analysis of some of its phases. It was found that the various
instruments used in measuring growth, inclusive of several types
of auxanometers, balances, recorders, horizontal and traversing
microscopes are in their diversity both adequate and precise to

1 Vogt, E. Uber den Einfluss des Lichts auf das Wachstum der Koleoptile von
Avena sativa. Zeitsch. Bot. 7: 193-270. 1915.

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 9

such a degree as to have solved most of the mechanical difficulties
so far as apparatus was concerned. The results presented in the
present paper were obtained by the use of a horizontal microscope
and by a number of auxanometers of the type described in 1901.!
Various types of levers and supports were made to fit special
preparations of plants (PLATE 1).

Nearly all studies of growth have been made on seedlings or
on the tender and slender parts of young shoots, or on minute
structures such as the sporangiophores of fungi in which it had’
been practically impossible to make any reliable determinations
of the constituency or physical condition of the growing structure,
or of its direct reactions.

The choice of material therefore assumed a major importance
in any possible advance that might be made in an investigation of
the matter. A review of the plants available at the Desert
Laboratory made it apparent that the platyopuntias offered
certain features by reason of which it might be possible to secure
measurements capable of correction and analysis to a degree not
attainable with any other material. The flattened mature joints
of these plants have an elongated oval outline with a length of
10 to 20 cm., a width of 8 to 20 cm. and a thickness of I to 3 cm.

Anew joint first emerges asa bud thickly sheathed with ephem-
eral leaves from one of the distal areolae of an old joint, in
March to May in the Tucson vicinity. By the time a length of
2 cm. is reached, both lateral and longitudinal expansion assume
proportions which are maintained until maturity is reached and
it is at this time that it is profitable to bring the apex of the bud
in bearing upon the lever of an auxanometer. The alterations
in length and width which ordinarily ensue may be illustrated
by the following measurements made with a ruler on a new joint
arising from an old one into which the bulb of a mercurial ther-
mometer had been thrust.

Length Width Joint Air
Mareh 15— 3. -P/M; .:..3:4 2.4 85° F. 83° F.
PeenG Aa Les Son, 2328 2.8 7s go “*
“ 19—-12:30 noon ....4.9 eau 65) 5° G7aeg
ve) 24=——easaOue Mos «525 .6" 4.0 88 “ Saar

1 MacDougal, D. T. Practical textbook of plant physiology, p. 291. Ig01. New
York.
2 Leaves cut off.

Io MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

A preparation suitable for such work consists of a rooted joint
separated from a plant in the previous season, and fixed rigidly
in a setting of plaster in a metal disk with the roots imbedded in
soil or depending in water. Although water-culture seems anoma-
lous for cacti, yet preparations showed normal activity through-
out a growing season with the roots immersed in ordinary water
from a shallow well.

Such joints offer the advantage of being mechanically firm
enough to support a lever counterweighted to give a bearing which
will allow the minute change in length to be recorded, and by
occasional adjustments of the instruments the course of growth
of a joint may be followed from the bud to approximate maturity,
a development which extends over two or three months.

The use of the opuntias as material for the study of growth
might raise objections based upon the obscure and possibly com-
plex morphogeny of these plants. Such objections would have no
real weight. A joint supposedly consists of a number of inter-
nodes which mature as one in a developmental period of several
weeks. These structures are in effect thick disks of plasmatic
colloids enclosed in a distensible epidermal membrane, and tra-
versed by a fibro-vascular system of cellulose also capable of
extension. Carbohydrates are formed within this system by
photosynthesis and the catabolic or respiratory action is one by
which a high proportion of acids is accumulated at low tempera-
tures and in darkness. Water is drawn into the disk through
basal connections, and some is lost through the stomatal openings
in a characteristic manner.

The opportunities for an analytical study of growth in such
plants were enhanced by the fact that the general course of water
loss had been determined by workers at the Desert Laboratory in
previously completed studies and that the daily and seasonal
variations in acidity had been followed in hundreds of instances in
certain species by Dr. H. M. Richards and by Dr. H. A. Spoehr,
while some measurements of the hydratation capacity or swelling
power had been made in 1914 by Mr. E. R. Long.

Observations on the growth of a joint might therefore be carried
through several weeks and the daily and ontogenetic variations
correlated with acidity, turgidity, hydratation, and transpiration
conditions exhibited by controls and material previously examined.

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH II

It is believed that no such previous relation between the actual
growth phenomena and internal conditions had ever before been
achieved in studies on this general subject.

- In addition to such determinations of the physical conditions
of the disks, the results of some measurements begun in 1911 upon
the general alterations in form and size of the joints were also
available. These show that while the main growth is accom-
plished during the initial season of enlargement, yet some distinct
variations in size ensue during the second season. The dimensions
of some joints of Opuntia discata at Tucson in the warm arid
climate of the Desert Laboratory and at Carmel in a cool equable
climate are given below:

MEASUREMENT OF JOINTS OF Opuntia discata:
No. 1. (Tucson)

Date Width Length
May a COW TODS. Akers uo enh: 6.5 cm. 7.0 cm.
Ay AB EGE SOLU. A. thank Ie 11.5 12.3
IN yA QUOI eh BE cee 03-4 14.6
ISM MONET OM2hb esctnc swears 14.0 15.0
SEDC ee 24h DOMMES cts nah ang chuck go seat 19.8 20.2
WATE Oy TOTS. )-hok neee Ge net oak 19.6 20.2
May cog kO snl O Sete. Gam acr a an yee 19.8 19.6
SIC We EO al OE es his oe siya. ooh. ae ONO 19.8
PVrtiey DS LOE Ae as: Soctirl sa aes 20.0 20.0
No. 2. (Tucson)
EAs A ORO RD hr sts a ss per he 10.8 12.0
Mayr ALO mMIOIZ:. Sete eh eee 14.1 P5a0
lane. “264 TOE Py Pea, J cee 15.1 ee
fe (Oy Ona hak at, pak lol ee 15.4 172
epee CD POLS ory hh ita on esp a 18.5 20.0
PMC OS LOT Ai ay eae cies 18.5 20.6
Weare Oe WOE Shs caddy ce ee lars oe 18.4 20.8
RMP ES LOL Bis 22% Sao ia, laid Be 18.2 . 20.0
ERP So LOLA Sto oy nli.'. lo Saines oe 2 18.0
No. 3. (Tucson)
pa CIEE 2 52 «SS aha ache 6.0 7.0
LIENS) es 10 fe A i rt ae 9.8 11.0
LGR: S015 55 (011 ar ea me Teo
jtieoenor2 te 28 11.8 mae
Sept a SaeumOIe ye 02s Ae ed Be n522 16.8
March Soemoms. 2.0.20 webs secs 15.3 072
INE SY 9 GREER eicais es sits fesd gos te: HB 17.0
ume) ne mrgiter sto vc ee eo... 15.3 17.0

Aprils Panigngie arte aloes. 16.2 V2

12 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

No. 4. (Carmel)

May: a2 SLOM 2a as. 3h anu aeeeee 3.8 5.5
JUG ay OWL Se Peecc & 5 o.orsi cl orcionore 6.2 10.3
luilyeebow hOT2 kt.) eo ake arama. 6.2 10.0
NUR TANTO 122 st, Bonen heikon ote 6.2 10.1
Hs\foy rill We (ETOWRD G0 ie eeeVA rarnte reeotetcs cc 6.5 10.5
ITA yates 3), OS = <1 egeuee tele ay her tate 6.5 10.5
July TA TOUGH Ce Soret eee eres 6.4 10.4
NOs 20 OES AE Reais bey.) ene 6.3 10.2

No. 5. (Carmel)
Mayra ay none tet ier tats eee aor 5.2
June 4707S 1OL2 ey 3 hehe eee 8.0 12.8
July 2 O12 ss eee ee ae oe 8.3 13.2
AUS il LOL2 eo... cee ee 8.2 13.5
DSEpty 30, LOU2 so. i. cc eer ek 8.5: 13.4
April) wOpsO1S). tyre ate aeeetee = 0 8.8 14.0
Miay 40352001 3.0.5. seneeeeee: oe 2 8.8 14.0
July 7ST. 3 acy eee ee ots « 8.8 13.4
ATISS a2 Ole TO Lait 5 ene eye eo) =) 9.0 13.0

No. 8. (Carmel)
Maia Pos pT O12: cen Seuceemnee (Pe 8. hot 6.3 Foul
Nine PSO WL O12 2 enepeteete no 14.0 wes
lyr S02, LOUD: heen ere eee = 2 14.2 18.1
NU Ta) TOLD SS, eematcyets inc. s: 3,2 14.3 18.0
SEPESE MO LOLS: so ete ee Beate oe 14.3 18.0
Aprile 9 s1Ol?.: eerie: ses 3 15.4 18.3
May? BiB TOLS 2h hence sone 15.4 18.3
July TA LOZ eee Reo cde 15.5 18.6
Alig 20) TOTS 75 ee ee ae oe 15.5 18.5

No. 12. (Carmel)

(Mature)

AT Ooe Me Aly LOL TA Somes PB aa ore 12.8 16.1
Mia er as TL OU2 eete eye ns si ottetor es 13.5 16.8
MEN LON LO Llp anes ee ae Oe 13.8 16.8
July I 21 OL Qe paras pire aisrerters 13.6 16.8
Pee CTT aL O02 9 ce ae cette ceed oie 13.0 16.8
Seve)» 1; LOL2c. ve) palace ise Tae 16.6
rN ofc WML? Debi 3 a te neg eR RN A eh er A 13.8 17:0
May oq 13, ROUSE a7 ra Ae teak ha eae 13.8 U7e0
July FGaSLOTA Bae etvs al ted OTR Ree 13.8 16.8
Atley W220) LOIS i ntieis * eee ete 13.6 16.8

The preceding tables convey the general features of develop-
ment of the joints, both in the semi-arid subtropical climate
under which the plants habitually thrive and in the cooler equable
climate of Carmel. It is to be seen that the rate and total growth
of the joints is much greater in Tucson with its higher number of

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 13

auxo-thermal units, and that the enlargement is halting and ir-
regular, in some instances actual decrease of length and width
being apparent (see measurements in bold face type) ; and that such
shrinkage was not an error was amply attested by the auxano-
metric data to be given below.

Many of the series of measurements of the growth of a single
bud extended over a hundred days. It was necessary to secure
rigid and secure mountings for plants which were to be kept under
observation so long. Preliminary arrangements for the experi-
ments to be carried out in 1915 were made by making cuttings of
old joints of sound healthy plants. After the wounded surface
at the bases had healed, some of the joints were put in an equable
low temperature dark room until needed: others were set in pots
of sandy soil and others were set in dishes as water cultures. The
beginning stages of development were anticipated by cutting a
slot in a metal plate or disk through which the basal part of a
joint might be passed so that a small segment including the cal-
loused surface and roots, if formed, projected clear of the disk.
The joint of the cactus would now be securely fastened in place
in the disk by a setting of plaster. After this had become firm,
the preparation was firmly clamped to the top of an earthenware
pot or dish in such manner as to eliminate all possibility of any
vertical motion. The bud would be arranged to bear against
the lower side of a counterweighted auxanometer lever. This
instrument was likewise clamped to its base in such a manner as
to eliminate errors which might be caused by irregular movements.
The auxanometers consisted essentially of recording drums re-
volving daily or weekly, on which pens traced the movements of
improvised levers. These levers were arranged as simple or
compound, according to the needs of the experiment. The growth
of a joint from the initial 2 cm. to I2-15 cm. necessitated peri.
odical adjustment of the instrument. This was generally done
by blocking it up on its base and then securing by heavy steel
clamps (FIG. 1).

Since some of the factors which would operate to cause changes
in external dimensions would also be operative in mature joints,
a number of these were mounted as above and put in contact with
auxanometric levers. Modification and control of the conditions
prevalent at Tucson were obtained by dark rooms, glass houses,

I4 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

etc. The course of growth of joints Nos. 1, 2, and 3 at Tucson
and of Nos. 4, 5, 8, and 12 at Carmel illustrate the widely ranging
intensities of environmental conditions at the first-named place
and the equable climate of the second.

Fic. 1. Measurement of variations in length of mature joint of Opuntia with
precision auxograph. The mercurial thermometer may be read at convenient intervals
for actual temperature of the joint while air temperatures are recorded by a thermo-
graph.

The record of No. 5 (Opuntia Blakeana) of the auxanometric
series may be used as a guide to the discussion of the growth
phenomena of a Hat joint of opuntia. This joint was put in
bearing with an auxanometer lever on March 27, 1915, when
its length was 17 mm. With the exception of brief intervals
necessary for readjustment of instruments, the history of the
developmental enlargement of this joint to ten times this length
was completely recorded for a period of 63 days. At the end of
this period the net increase in length became very small and the
variations in length were of the type displayed by a mature joint.

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 15

The measurements of mature joints which had been made by
rulers, calipers, horizontal microscopes, etc., showed that changes
in dimension of some amplitude due to the amount of the water
balance occurred in these plants. The known factors to which
such changes might be due were the water supply, transpiration,
temperature, variations in acidity, etc., all of which would affect
the growth of young joints.

It was important therefore that the general nature of the
changes be made out and the parts played by the contributory
factors analyzed. In accordance with this requirement the mature
joint bearing the new bud (No. 5) was fixed firmly in plaster with
its root-bearing base immersed in a vessel of water on March 4,

Fic. 2. Auxographic tracings of the variations in length of mature joint of Opuntia
Blakeana, No. 5, preceding the development. of the new joint and during the earlier
part of its growth, X 83. Elongation produced a downward movement of the pen.
The record is complete for 42 days, starting in a period of equalizing daily variations,
including a period of enlargement and ending in a stage of decreasing length.

1915. An auxanometer lever was put in contact with a space
between two areolae on the apical margin and the features of
changes in volume are well shown by tracings of the actual record
given in FIG. 2, the actual elongation being magnified twenty
times and denoted by downward movement of the pen. The
old joint had suffered the usual winter depletion of water as it
stood in the open, and its transferral to the experimental setting
duplicated the conditions under which it would have begun to
take up water more rapidly from the moist soil. The increase of
the water-balance began to be manifest on the eighth day after
the experiment was begun (see uppermost tracing in FIG. 2) and

16 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

reached its general maximum in seventeen days. The accumu-
lation of such a balance was accompanied by an actual increase
of 5 mm. in length, which would be about .4 per cent. of its initial
full length. This upward thrust of the mature joint would of
course carry the young bud, the growth of which was measured,
and would constitute about .3 per cent. of the upward movement
of its apex.

The most obvious and prevalent feature of the expansion of
the old joint was the fact that the greater part of this occurred
between 11 A.M. and 2 P.M. daily. Diminished elongation or
actual shortening followed soon after 2 P.M. Both the mature
and the young joint stood plane in the meridian and during the
period of most rapid elongation presented their margins to the
source of light. The preparation was accidentally placed where
the shadow of a door frame 20 cm. in width and 110 cm. distant
passed across it between 9 and 10 A.M.

The principal daily variations are illustrated by the tracings
March 8-15, and March 15-22. If the records of March g, 10
and 11 be considered, it will be seen that the course of variation
was such that the length of the old joint remained unchanged
through a night with the temperature ranging from 50 down to
47° F. Arise in temperature of the air from the last named figure
to 63° F. at 4 P.M. was accompanied by the following changes:
a slow decrease in length continued from the previous night
until 10 A.M., broken by an elongating action while under the
passing shadow at9 A.M. A positive elongation at 55° F. began
at 11 A.M., and was marked in character until 1 P.M., when it
checked, although the temperature was still rising to favorable
intensities for absorption, reaching 63° F. at 4 P.M. Before this,
however, shortening had begun and continued on through the
night with repetition on the following days. This is still more
marked in the record of March 15-20. The momentary elonga-
tion due to shading was displayed at 9 A.M. Shortening or a
very slow increase set in at 2 P.M. and lasted until 11 A.M.
Two or three hours of lengthening ensued, then cessation of
expansion, complete or nearly so. On March 20th the prepara-
tion was set in the open at 8 A.M., the illumination being more
intense than in the greenhouse. Elongation began at once and
ran five hours, ending suddenly at 1 P.M. and decrease set in

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 17

which conformed in its general aspects to the behavior of the
previous period.

The daily increase in length amounted to .6 mm. as a maximum
and, as the longitudinal dimension of the joint free of the support
was I5 cm., the coefficient of expansion was I in 250 or .4 per cent.
On Wednesday, March 17, this increase began at 10 A.M. at
63° F. and the expansion followed while the temperature rose to
72° F. during the next three hours. Some expansion continued
with a fall of 2° F. during the next 4 hours. It is evident, how-
ever, that the decreasing expansion is not to be attributed chiefly
or solely to the temperature relation. This is also supported by
the fact that on the following day the increase of a total amplitude
of about .4 mm. began at 10 A.M. at 60° F. and went forward
rapidly until 3 P.M., the sky having become overclouded at
noon, and continued to increase until midnight under the equalized
conditions. The temperature remained between 69° and 70° from
noon until 6 P.M. and had fallen to 62° F. by midnight.

That the enlargement in question was not entirely growth, was
evidenced by the fact that before the close of the observations on
June 1 a large part of the total increase noted above (2 mm.)
had been lost by shrinkage, and the inevitable loss of water during
the remainder of the season would probably result in changes
similar to those shown by Nos. 2 and 3. (Tucson, 1913-1914.)

It would appear that the alterations noted above are reversible
in greater part and must therefore be attributable to osmotic
action and hydratation.

Not the least remarkable aspect of the matter, however, is the
fact that the growth enlargement of joints follows a course fairly
parallel to that described.

The bud of No: 5, for example, began to accelerate at 9 A.M.,
April 3, temperature 65° F., and followed the rise until 3 P.M.
and then slackened (temperature 75° F.), although the temperature
continued at this intensity for at least an hour longer. From
6 P.M. until 8 A.M. the rate was a straight line and parallel to
the temperature record. Acceleration from here lagged, repeating
the events of the previous day. (FIG. 3.)

The record of April 6 illustrates another phase. The old joint
was undergoing continuous shortening at a fairly uniform rate.
Temperature rose from 60° at 6 A.M. to 66° at 11 A.M., varying

18 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

between the two figures until 6 P.M., the rate of growth being a
straight line record.

The major part of the growth enlargement being accomplished,
the newly matured joint began to exhibit the daily variations
hitherto displayed by the mature joint. Increase in length in
progress at daylight was slightly accelerated at about 8 A.M. and
continued with the rising temperature (May 11—68° F.—76° F.,
until 2:30 P.M.) then slackened, although the temperature kept
up to 78° F. at 8 P.M. By 4 P.M. a shrinkage began which

NOON NOON NOON NOON NOON NOON NOON

Fic. 3. Auxographic tracings of growth of joint No. 5, of Opuntia Blakeana, X 1y'r-
Downward movement denotes elongation. The date of beginning of each partial record
is given. Thus the record of beginning April 2 extends to the evening of April 4. The
record for the entire week beginning April 19 is given.

continued until about midnight, when with a temperature now
falling to 70° F. at 7 A.M., elongation began, and continued as
on the previous day, until mid-afternoon. A behavior of a modi-
fied type was presented by the growth of the young bud of Opuntia
Blakeana No. 13,a joint which had been rooted in sand and
covered with a screen of glass (G55A62), which transmits only
the violet rays and the longer red waves, from November until
it began to develop a bud late in March, 1915.

April 9, 1915, it was removed to the greenhouse and put in
contact with an auxanometer in which the compound lever mag-
nified the motion by 23. From the first the rate of growth was
accelerated, beginning at about 9 A.M. and continued at a high
rate until about 4 P.M. or later. Slackening then occurred and
the actual rate decreased until about 8 A.M. This last-named

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH I9

retardation effect became more accentuated with the development
of the joint until an actual cessation of growth occurred on the
night of May 9 and 10. The retarding conditions from this
time became accentuated so that on May tr actual shortening
was displayed, and the remainder of the period of observation
was made up alternating daylight-elongating phases and nocturnal-
shortening phases (FIG. 4).

NOON

Fic. 4. Auxographic tracing of growth and variations in length of Opuntia Blakeana,
No. 13, for the period month beginning May 6, and ending June 5, 1916. Elongation
is denoted by upward movement of the pen and the actual change in length is multi-
plied 92 times.

At the time of maximum rate of elongation the daily increase
was equivalent to nearly 1 mm. In the period following, when
the daily increase ceasing in mid-afternoon was followed by a
decrease in length, the elongation amounted to .5 mm. daily, and
would be followed by a shortening of .3 mm., leaving a net total
growth daily of .2 mm. This net accretion diminishes with the
approaching maturity of the joint. This last-named record was
taken during the high temperatures of May.

The three types of change in volume illustrated by these mea-
surements agree in that accelerating elongation coincides with the
duration and increasing intensity of illumination in the forenoon
and that the continued rise in temperature (within the tonic range)
and of the illumination is accompanied by a retardation or a
shrinkage in the afternoon.

If we consider the known possibilities in the way of change of
volume attention would naturally be turned first to water-loss.

20 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Thus it might be supposed that the transpiration loss might reach
an amount in the afternoon which would result in a condition
analogous to wilting. Extensive measurements, however, have
shown that the maximum transpiration of these cacti within the
ranges of temperature 60-80° F. occurs during the night period
and that it comes down to a minimum during the forenoon at
about the time elongation begins to accelerate, and that it does
not rise materially until the end of the daylight period.

That the water-balance is actually decreased at night and
increased by day has been found by Mrs. E. B. Shreve, who
says of a cylindropuntia,! “‘It was found, under conditions of
average transpiration, such as occur in the greenhouse in summer,
that the water intake at night is less than the outgo, while during
the day the intake is greater than or at least equal to the outgo.
. . . An examination of the water-content of stems from plants
in the open and from the greenhouse showed that the highest
water-content is at 5 P.M. after the close of a bright day, and the
lowest just before daylight the next morning, with an intermediate
amount at noon.”’

Next there is the swelling capacity of the material of the joints
to be considered, with especial relation to the decreasing acidity.
It has been well established by the work of Spoehr, Richards,” and
Long that the acidity of the sap of these cactus joints decreases
steadily throughout the day and reaches its minimum at a varying
time late in the afternoon—about two hours after the rate of
growth manifests such a remarkable decrease. According to
Long’s results,’ the hydratation capacity of separated living
sections zucreases with the decrease of the acidity during the day,
being at its greatest at 5:30 P.M. It is evident therefore that
growth elongations do not follow a course parallel to the capacity
for distention, whether this be caused by swelling (hydratation)
or osmosis and resultant turgidity. The rate of growth is at a
minimum or approaching it at a time when the capacity for the
tissues for taking up water is greatest, and when they actually
contain the highest proportion. Growth in these cacti therefore

1 Rep. Dept. Bot. Research, Carnegie Inst. of Washington, 98, 99. I915.

2 Richards, H. M. Acidity and gas interchange in cacti. Publ. Carnegie Inst. of
Washington, no. 209. 1915.

3 Long, E. R. Growth and colloid hydratation in cacti. Bot. Gaz. 59: 491-497.
1915.

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 20

is not primarily determined by water-conditions as affected by
light either directly, or indirectly by variations of the acidity.
Irreversible changes in form and size are intimately and primarily
dependent upon the amount and availability of the substances
which for lack of a more definitive term may be designated as
“building material,”’ and upon its use by respiratory action, as is
well evidenced by the fact that the process sustains an intimate
relation to temperature, so that great variations in the rate are
induced by temperature changes so small as 2 or 3 degrees F.
The facts to be taken into account justify the assumption that the
actual building material is derived from accumulated food in a
hydrolized condition for example, the velocity of the chemical
changes depending directly upon the temperature.

This assumption harmonizes with the repeated observation
that growth at the higher temperatures proceeds at rates which
soon fall off. If growth took place at a rate governed by the
adduction of plastic material no such abrupt acceleration would
be possible, while as a matter of fact the rate rises suddenly after
a mode similar to the increase in reaction velocities.

Accelerations in rate of growth may be capable of interpretation
upon this basis but reaction velocity alone as governed by temper-
ature does not afford an adequate explanation of the slackening
and cessation of growth under favorable temperature conditions.

If reaction velocity may not be held to account for a decrease
in rate, attention would naturally be turned next to the size of
the supply of material and its availability for construction pur-
poses.

The analyses of Richards, Spoehr, and Long show that owing to
the type of respiration prevalent in these plants, organic acids
accumulate in the cells during the night to a concentration of
N/20 to N/ro, and their disintegration begins with the dawn and
continues throughout the day so that these substances are present
in minimum quantity by 4 P.M. The breaking down of these
acids includes a web of processes not capable of ready description,
but which does not yield substances capable of being used as
building material by the plant.

On the other hand, these acids are the partially oxidized waste

‘For recent measurements, see Lehenbauer, P. A. Growth of maize seedlings in.
relation to temperature. Physiological Researches 1: 247-288. 1914.

22 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

products of incomplete respiration, and their presence operates
to prevent the respiration and use of the sugars as a source of
energy and as building material. The slow growth at night may
therefore be attributed mainly to high acidity impeding respira-
tion and the higher rate of water-loss would also tend to lessen
the possibilities of increase in length and thickness.

The disintegrating action of light on these acids would at some
time toward midday bring the acidity down to concentration
where its impeding effect on respiration would be largely cancelled
and growth would then go on at a rapidly accelerating rate until
the supply of accumulating sugars was used up. Such exhaustion
of the food-material might occur at any time, but in the cacti
generally comes at Tucson two or three hours after midday, after
which time construction would be largely from sugars diffusing
directly from the photosynthetic tracts. The general features
of the daily course of growth show some precession with the ad-
vance of the seasons and the higher temperature and light maxima
at Tucson. The auxographs of Opuntia discata made at Carmel
under equable conditions also harmonize with the conclusions
given above.

The above explanation seems to account in an adequate manner
for the irreversible changes taking place in the growing plant,
whether illustrated by the growing bud or by the large joint in
its second year and designated as ‘‘mature’’ though still capable
of some growth. It is evident that coincident with growth and
extending throughout the active existence of the stem a series of
reversible changes in size takes place. This is most noticeably
exemplified by the case of Opuntia Blakeana No. 13, which had
been subjected to light rays of wave length below .52 mu for four
months before growth began. This plant showed extremely rapid
accelerations of growth in the forenoon and abrupt slackenings
at midday, which soon ran into shrinkages in length as if the
hydratation capacity had been altered, following the failure of
the supply of building material (FIG. 4).

This superposition of reversible and irreversible changes makes
our problem complex, but by no means insoluble. Furthermore,
it is reasonably certain that the two types of change ensue in the
thin leaf of wheat and in stems as well as in the cacti used in our
experiments, this material, however, offering phenomena in which
the phases are thrown into high relief.

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 23

It will be best to take up this phase of the matter at the time
of day when growth has come down to a low rate in the afternoon.

If it be assumed that a slackening does ensue by reason of the
practical exhaustion of the reserve supply of material it would
then be seen at once that construction might proceed only at the
expense of photosynthetic products diffusing directly from the
chlorophyllous layer to the enlarging tracts. The disproportion
of the growing mass to the chlorophyll layer in a cactus joint is
so great that it might readily be seen that growth may not be
supported for any extended period or to any great extent at the
expense of coincident photosynthesis. It has long been known that
rapidly extending organs such as leaves may not be built up by
material derived from their own reducing processes.

The enlargement of a joint having been carried through the
earlier part of the day by actual construction and continued late
in the afternoon by increased swelling power of the deacidified
tissues, would decrease and come to zero with the falling tempera-
ture of evening, and this effect may even be carried so far that
the capacity of the colloids might be reduced below the amount
acquired at the high afternoon temperatures and some water might
be actually extruded. So much for the direct temperature effects.
The indirect effects may be quite as large or important. The
absence of light and the failure of its disintegrating effects, to-
gether with the low temperature, would result in an increased
accumulation of acids reaching a maximum at daybreak, and this
increase would also lessen water-holding capacity and osmotic
pressure with the result that all forms of distensive action would
be lessened, cancelled or reversed, tending to check elongation
or to produce actual shortening. This ready yielding of water
resultant from the above action would, it seems, facilitate water-
loss to some extent, and that it does so is suggested by the apparent
coincidence of low hydratation capacity and high transpiration
rate. It may be well to emphasize the fact that a joint of a cac-
tus, a simple stem, or the still more rudimentary Phycomyces
sporangiophores are not homogeneous as to chemical composition
or simple as to mechanical qualities. The agents affecting hydra-
tation may not cause identical effects in cell-wall, in protoplast,
and in accessory slimes or mucilages. When such dissimilarly
reacting elements are mechanically bound together as in the stem,
the resultant change in volume may not be easily analyzed.

24 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

In recapitulation it is to be said that the auxographic record of
a plant is a resultant of its reversible and irreversible changes in
form.

The permanent changes in the cactus dependent largely on its
type of respiration take place in the day time when the accumu-
lated acids are disintegrated by the action of light, and growth
continues at the expense of the available sugars until the balance
or supply is reduced to a minimum. Reversible changes in form
rest upon water-holding capacity and the distensive action of
osmotic and hydration pressure. Temporary enlargements cumu-
late with decreasing acidity and decreases or shrinkages follow
falling temperatures and heightened acidity, being coincident in
some cases with maximum transpiration. With this interpreta-
tion’of the auxographic record accepted, it is now possible to pro-
ceed with a general summary of the relation of temperature and
light to the processes under discussion. The facts already pre-
sented tend to show that temperature influences the diffusion of
food-material at a low simple ratio, that food-formation, hydro-
lysis, and the formation of building material take place under
van’t Hoff’s law, and as temperature also affects osmotic pressure,
permeability, and hydratation capacity, it is the dominating
agency in determining the course, rate, and consequently the
final amount of growth. It may have supra-optimal, as well as
minimum effects.

Light, especially the shorter wave-lengths, exerts a neutralizing
or coagulatory action on many of the colloids of the protoplast,
but as such radiations have the least penetrating power, this
action is most marked in the minute organisms, or in those with
translucent membranes or outer integuments. It is in accord
with these facts that the action of enzymes may be retarded by
light of certain wave-length and intensity, and also that stems
developing in the illumination of a mercury vapor arc lamp show
grotesque departures from the. normal form. There seems to be
a marked specificity of the wave-length upon the relative develop-
ment of various tracts, but these morphogenic effects may be
dealt with in another paper. How far ‘permeability’? as de-
pendent upon the relations of disperse phase and disperse medium
of protoplasm may be affected by light is not yet clear. It is
clear however that the disintegration of clogging or smothering

MACDOUGAL: MECHANISM AND CONDITIONS OF GROWTH 25

acids which retard respiration and growth and lessen hydratation
capacity is a process which may affect the rate and amount of
growth in a very important manner.

Since these various effects may be widely variant with the
mechanical structure and composition of the plant there is the
amplest confirmation of my own generalization made fourteen
years since that the ‘‘action of light upon growth is not invariable.”’
The most recent confirmation of this conclusion is that of Blaauw,
who finds important differences in the “ photo-growth reactions ”’
of the sporangiophores of Phycomyces and of hypocotyls of Helz-
anthus. The considerations presented in the foregoing paper
would make a similarity of response between two organs of such
unlike structure highly improbable.

The more important suggestions, inferences, and conclusions
arising from the work described above may be briefly re-stated as
follows:

I. The joints or segments of platyopuntias accomplish nearly all
their total enlargement during sixty to one hundred days of the
initial season in the Tucson climate. Enlargement and secondary
growth may take place as determined by branching and environic
factors, in succeeding seasons.

2. The changes in volume of joints in the second or succeeding
seasons include daily reversible alterations amounting to 1/250 of
the total length. :

3. Reversible enlargement begins in mid-forenoon and continues
until afternoon, when contraction ensues and with various modifi-
cations may continue until the following morning, daily.

4. Reversible daily elongations of 6 mm. were recorded and irre-
versible growth elongations of ten to twenty times this amount
were recorded.

5. Elongation takes place during the daylight period, accom-
panied by decreasing acidity and lessened transpiration. The
maximum rate occurs about mid-day. Decrease in rate takes place
after mid-day, while the air temperature is still of optimal inten-
sity and the plant has the highest water content.

6. Reversible changes in mature joints synchronize with growth
of young joints, but the extent to which the reversible changes
enter into or accompany growth has not yet been determined.

7. The general features of the daily growth record suggest that

26 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

enlargement takes place after smothering or clogging acids have
been broken down and that it ceases when the supply of ‘‘ building
material’ is reduced to a minimum.

8. The action of light on growth has been considered only with
reference to its disintegrating effects on acids, and as affecting
transpiration and air-temperature. The direct action of light on
protoplasts and on body temperatures will be discussed in a later
paper.

Explanation of plate 1

Group of auxographs recording variations in volume of Opuntia discata. A joint of
this plant growing as a water culture at the left. Desert Laboratory.

VIVOSIG VILNOdQg AO

HNWNATOA NI SNOILVINVA DNIGUOOAA SHAVADOXNAY AO dnOutr)

I @ALV1d “[A ANNIOA

NAduV*)

‘LOG “A °N ‘Way

—

ARE TETRACENTRON, TROCHODENDRON, AND
DRIMYS SPECIALIZED OR PRIMITIVE TYPES?

W. P. THOMPSON and I. W. BAILEY

University of Saskatchewan Bussey Institution, Harvard University

(WITH PLATES 2-4)

The presence of vessels in the xylem of Angiosperms and their
absence in that of the Gymnosperms is one of the striking
differences between these two great groups of plants. The taxono-
mic significance of the absence of vessels in Gymnosperms is likely
to be emphasized by the work of Lignier and Tison upon Wel-
witschia, and that of Thompson upon Gnetum, which indicates
that the Gnetales belong in the former rather than in the later
group. This raises the question, are there, among living Angio-
sperms, forms that have retained the primitive, Gymnosperm
vesselless type of structure?

Among the Ranales there are four well-established genera, .
Tetracentron, Trochodendron, Drimys, and Zygogynum, that, owing
to the simplicity of their xylem, have been compared with the
Conifers. In 1842 Goeppert noted the absence of vessels in the
xylem of Drimys, and his observation has since been confirmed
by a number of botanists, notably by Solereder and Van Tieghem.
Absence of vessels has also been recorded in Tetracentron, Trocho-
dendron, and Zygogynum by Eichler, Harms, Van Tieghem,
Solereder, and others. Opposed to the observations of these
investigators are the statements of Parmentier, that vessels occur
in Tvrochodendron and two species of Drimys. However, it has
subsequently been shown by Van Tieghem that Parmentier’s so-
called Drimys Muellert and D. vascularis were wrongly identified,
and undoubtedly do not belong in the genus Drimys.

More recently, Holden! has advanced the idea that the Magnoli-
aceae are forms that have become specialized through reduction,
and, therefore, are not primitive as has been considered probable by
a number of botanists and geologists.

‘Holden, R. Reduction and reversion in North American Salicales. Ann. Bot. 26:
I7ie 1912.

28 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The evidence, advanced in favor of this view, may be briefly
summarized as follows: Diffuse! wood-parenchyma is primitive,
since it occurs in many Gymnosperms and in the Casuarinaceae,
Fagaceae, Betulaceae, Juglandaceae, and Rosaceae. Vasicentric?
wood-parenchyma is a derived and more recent type, since it
occurs in the highest Angiosperms, the Oleaceae, Ulmaceae,
Leguminosae, Compositae, etc. In the Salicaceae and Mag-
noliaceae the parenchyma is usually terminal,’ but may be vasi-
centric in roots, young stems, and traumatic tissue. Interpreted
in the light of the ‘‘laws of recapitulation, reversion, and retention,”’
these facts show terminal wood-parenchyma to have been derived
from vasicentric. Therefore, the Salicaceae and Magnoliaceae
are specialized families that have originated by “‘reduction”’ from
advanced types of Angiosperms.

There are, however, important objections to this type of reason-
ing. Even if it be admitted that laws of recapitulation, reversion,
and retention can be formulated, it is extremely difficult to apply
them logically in phylogenetic discussions, since frequently no
reliable evidence is available to show whether a given character
in a given region is cenogenetic or truly palingenetic. This would
be very likely to be the case in dealing with parenchyma, cells
that function in storage and other physiological processes, and
are particularly sensitive to the effects of environment. Further-
more, it is by no means certain that, because a selected character
is ‘‘progressive” or ‘‘regressive,”’ a group of plants, the sums of
all characters, are moving in a similar direction. Thus, even if
it be granted that the simple flowers of the Amentiferae are
primitive (not reduced, as is held to be the case by many botan-
ists), and that the Magnoliaceae formerly possessed vasicentric
wood-parenchyma, it does not necessarily follow that all charac-
ters in the former group are primitive and that Tetracentron and
Drimys once possessed vessels and have lost them.

In view of these facts, the writers decided to study the Mag-
noliaceae and allied families in the endeavor to secure evidence
that might indicate whether these families have become specialized
through reduction or have retained a number of truly primitive
characters. In the following pages are summarized the results

1 Scattered among the tracheids or fiber tracheids.

2 Clustered about the vessels.
’ Confined to the end of the year’s growth.

THOMPSON AND BAILEY: TETRACENTRON, ETC. 29

of our observations upon the xylem of Tetracentron, Trochodendron,
and Drimys.

FIG. I is a photomicrograph of a transverse section of a two
year old stem of Ginkgo biloba L., and illustrates the typical
vesselless xylem of Gymnosperms, which is in marked contrast to
that of the Angiosperms, shown in FIG. 5, a transverse section of a
young stem of Schizandra chinensis Koch. This difference in
xylem structure is clearly illustrated in FIGS. 6 and 10, more
highly magnified transverse sections of Pinus palustris Mill. and
Swietenia Mahagoni Jacq.

FIG. 4 is a photomicrograph of a transverse section of a young
stem of Tetracentron sinense Oliver. The xylem of the central
cylinder and leaf traces is composed of radial rows of tracheids,
and vessels are entirely absent. Similar xylem, which is even
more typically coniferous, is shown in FIG. 2, a cross section of a
young root of the same species.

Fic. 3 illustrates the characteristically coniferous structure of
a seven year old stem of Tvrochodendron aralioides Sieb. & Zucc.
and FIG. 7 shows, under higher magnification, part of an annual
ring of the mature wood of this species. The differentiation of the
xylem into thin-walled ‘‘spring’’ tracheids and_ thick-walled
“summer” tracheids closely resembles that of many Conifers
(compare FIG. 6).

The entire absence of vessels in Tetracentron and Trochodendron,
in regions! that are supposed to be conservative of ancestral
characters, is clearly illustrated in FIGs. 2, 3, 4, 8, 11, 12. In
fact, the writers have been unable to find vessels or vestiges of
vessels in Tetracentron, Trochodendron, Drimys Winteri Forst.,
D. colorata Raoul, and D. axillaris Forst.

Not only are vessels absent in the xylem of these plants, but the
tracheids are typically coniferous in form, structure, and general
arrangement. Thus the bordered pits, as in the case of the
Gymnosperms, vary considerably in form and arrangement.
Scattered circular pits, the commonest coniferous type, occur in
the thick-walled tracheids of the summerwood of Tetracentron
and Tvochodendron, and in many of the tracheids of Drimys.
In the large thin-walled spring tracheids of the former genera
and in the tracheids of certain species of Drimys the bordered pits

1 Root, seedling, young stem, node, leaf, etc.

30 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

are crowded and much elongated (FIG. 14) resembling those which
occur in a number of extinct Conifers, e. g., Xenoxylon latiporosum
(Cram.) Gothan. Multiseriate pitting of the araucarian type of
arrangement occurs in Drimys axillaris and D. colorata, particularly
in the wood of the roots. Araucarian pitting also occurs in Tetra-
centron, in large, short tracheids that are to be found just below
the nodes. These tracheids (FIGs. 15 and 16) unlike the majority
of the tracheids, are abundantly pitted on their tangential as
well as their radial walls, and appear to function in facilitating a
rapid radial flow of water to the ‘‘entering”’ traces of the leaves
and rootlets.

Particularly significant, however, is the distribution of wood-
parenchyma in Tetracentron, Trochodendron, and Drimys. In the
first two genera and in Drimys Winteri it is diffuse. In Tetra-
centron and Trochodendron the parenchyma is abundant and
scattered throughout the thick-walled tracheids of the summer-
wood (FIGs. 7 and 13), whereas in Drimys Winteri it is usually
much reduced in amount. In Drimys colorata (FIG. 9) and D.
axillaris diffuse parenchyma with transitions to terminal and
banded types occurs in the stem and root.

If these facts are interpreted from the point of view of the so-
called laws of recapitulation, reversion, and retention, and Holden’s
hypothesis in regard to the taxonomic and phylogenetic significance
of the distribution of wood-parenchyma, it is evident that Tetra-
centron, Trochodendron, and Drimys must be considered to be
primitive types of Angiosperms, since they possess diffuse paren-
chyma and do not show vestiges of vessels in the root, seedling,
node, leaf, and other supposedly conservative regions.

There seems to be no evidence, therefore, to indicate that
Tetracentron, Trochodendron, and Drimys once possessed vessels
and have lost them. In fact, all the evidence at hand seems to
indicate that these genera have retained a number of ancestral
Gymnosperm characters. As will be shown in a subsequent
paper, the Magnoliaceae and allied families are extremely variable
in their external and internal characters, and show numerous
transitions from apparently primitive to advanced and _ highly
specialized types of structures. This is true of the flower, leaf,
node, xylem, phloem, cortex, etc.. It appears, accordingly, to be
highly improbable that the members of this group are forms that

THOMPSON AND BAILEY: TETRACENTRON, ETC. aI

have been “‘reduced” from advanced and more complex types of
Angiosperms.
SUMMARY AND CONCLUSIONS

Vessels are entirely absent in the secondary xylem of Tetracentron,
Trochodendron, Drimys colorata, D. axillaris, and D. Wintert.

Vestiges of vessels do not occur in the root, seedling, young
stem, node, petiole, traumatic tissue, and other regions that have
been considered to be retentive of ancestral characters.

The form, structure, and arrangement of the tracheids of the
xylem closely resembles that of the Gymnosperms and _ there
seems to be no valid reason for not considering the three genera
primitive as far as their xylem structure is concerned.

The wood-parenchyma is diffuse in Tetracentron, Trochodendron,
and Drimys Wintert. In D. colorata and D. axillaris it shows
transitions from diffuse to banded and terminal.

The distribution of parenchyma in these three genera makes
it seem improbable that the terminal parenchyma of the Mag-
noliaceae originated through reduction from the vasicentric con-
dition.

There appears to be no reliable evidence to indicate that the
Magnoliaceae and allied families are forms that have become highly
specialized through reduction from advanced types of Angiosperms.

In conclusion the writers wish to express to Mr. E. H. Wilson
their sincere thanks for material of Trochodendron aralioides, and
to Professors A. J. Eames and E. W. Sinnott for material of
Drimys colorata and D. axillaris.

Explanation of plates 2-4

Fic. 1. Ginkgo biloba, transverse section of two year old stem, X 13.
Fic. 2. Tetracentron sinense, transverse section of four year old root, X 18.
Fic. 3. Trochodendron aralioides, transverse section of seven year old stem, X I1.
Fic. 4. Tetracentron sinense, transverse section through nodal region of a young
stem, X 23.

Fic. 5. Schizandra chinensis, transverse section of young stem, X 16.

Fic. 6. Pinus palustris, transverse section of mature wood, X 50.

Fic. 7. Trochodendron aralioides, transverse section of mature wood, X 40.

Fic. 8. Tvrochodendron aralioides, transverse section of seedling stem, X 60,

Fic. 9. Drimys colorata, transverse section of stem, X I10.

Fic. 10. Swietenia Mahagoni, transverse section of mature wood, X 30.

Fic. 11. Tetracentron sinense, transverse section of petiole, X 20.

Fic. 12. Trochodendron aralioides, transverse section at base of leaf, & 25.

32 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Fic. 13. Trochodendron aralioides, longitudinal radial section through summer-
wood, showing diffuse parenchyma, X 300.

Fic. 14. Trochodendron aralioides, longitudinal radial section through the spring-
wood and a small portion of the summer-wood, X 250.

Fic. 15. Tetracentron sinense, longitudinal tangential section of stem, showing
lateral leaf-trace and subtending tracheids, X 45.

Fic. 16. Tetracentron sinense, longitudinal tangential section through the short
tracheids below entering leaf-trace, 100.

Fic. 17. Tetracentron sinense, transverse section of phloem, showing two com-
panion cells, X 600.

PLATE

Wall

VOLUME

Bor. GARD

eM.

rem ees,

ay,
mnie

: =
ee

F5
FITZ

BARI
ae See at
ie

TETRACENTRON, ETC,

NEE

AND BAILE

THOMPSON

Mem. N. Y. Bor. GARDEN VOLUME VI, PLATE 3

68,

re?

it Part
Sees.

KY
fis
E

pS.
2a;5's's
Saat:

THOMPSON AND BAILEY: TETRACENTRON, ETC.

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 4

> ~; :

_~
Ye 9. ee

BS
.
SS
>
+
Se
Ns:

cE;
3:

tcc

THOMPSON AND BAILEY: TETRACENTRON, ETC.

DIRECTING FACTORS IN THE TEACHING OF
BOTANY

ARTHUR H. CHIVERS

Dartmouth College

In studying the program for this anniversary it has occurred
to me that the subject I have chosen may seem somewhat out of
place in these meetings, since it savors of pedagogy, and offers no
indication of research into the field of botany. It is my intention,
however, to avoid an extended philosophical discussion, to which
my subject might easily lead, and to speak as briefly as possible
of the problems which have impressed me very deeply during my
career as a teacher of college botany, and of certain possible factors
which may serve as guides in the solution of these problems. And
I have ventured this with greater courage since I believe that they
are problems, in the nature of real dangers, which concern us all,
whether we are at work in the direction and maintenance of a
botanical garden, or in the teaching of botany in our public
schools, colleges, and universities, or in the various branches of
applied botany.

The greatest problem which endangers botany today is the
tendency to commercialize its product. We hear a great deal of
talk to the effect that this is an extremely practical age in which
we are living. If any one doubts this statement let him teach
in an American college for a sufficient length of time to learn the
attitude of the typical undergraduate student. Nowhere do we
feel the tremendous pressure away from the theoretical and toward
the utilitarian more than in our colleges, and especially is this true
in those institutions which are able to attract students into con-
tinuous courses of study through well-equipped affiliated schools
of a graduate nature. The results obtained in the botanical
department of one of our well-known New England colleges
during the last nine years may be cited as evidence for the truth
of my statement. During this period more than twenty-five

+ a3

34 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

hundred men completed the beginning course in botany. Of
those who continued the work in the higher courses by far the
largest number entered schools of sanitary engineering, agriculture,
landscape architecture, and forestry, while those contented to
continue in purely botanical work were few indeed. It is probably
not far from the truth to say that 99 per cent. of the men who com-
pleted the work of the department during those nine years repre-
sented a commercialized product.

From this eagerness of the undergraduate to turn botanical
training into dollars and cents has come a constant pressure to
shift our standard, and to revise our courses, introducing the
practical as we chose to call it, and thus making our courses inter-
esting. Much of our college work, therefore, has become an
hotchpotch of commercial, and a smattering of foundational,
botany.

As a guiding factor to this tendency I would make an appeal
for a strong and vigorous training in scientific botany in our
colleges. During the last few years, for reasons already indi-
cated, I have experienced a strong and growing pressure to intro-
duce more and more work of a practical nature into the beginning
courses, but thus far at least I have persistently held to my idea
of what a foundational course ought to be, namely; a thorough
training in the morphology of as many representatives as possible
from the great groups of plants, together with a limited discussion
of their economic importance and their physiology. There is no
more excellent road for the beginner to a good knowledge of the
seed plants than the complete mastery of such a text as Gray’s
Structural Botany, followed by a thorough drill in analysis.

Let no one suppose that I am inclined to discourage the prospec-
tive landscape architect, or the scientific agriculturalist, or the
sanitary engineer, or that I do not appreciate the splendid work
which the various branches of applied botany have accomplished
in recent years. But I do insist that men so trained are not in
any way to be classified as botanists, that their work is not botany,
and that the science must be protected against the tremendous
pressure of the college student who is all too willing to plunge
directly into commercial botany, before any adequate foundation
has been laid.

The second problem to which botanists should devote greater

CHIVERS: DIRECTING FACTORS IN TEACHING OF BOTANY 35

attention is the teaching in our public schools. Too long the
theory has been held by those responsible for such work, that
any teacher not otherwise fully occupied should be capable of
handling the botany. The high school of one of our well-known
New England cities recently handed over the botany and zoology
to a classmate of mine who, during his college course, had received
no training in these sciences. His inquiries regarding the best
method for preparing himself, in two months, to teach these
subjects, were to me no less than pathetic. I have no doubt that
on inspection we might find many teachers explaining the anatomy
of the dandelion head as that of a single flower, and the columella
of bread mold as arising from a cross wall, which, by a process of
bulging, arrives at its final position in the sporangium.

That the teaching of botany of the present day is of a better
character than formerly we are all willing to admit, but there is
still some opportunity for improvement in some of our schools,
and great need for improvement in others. Greater care and
wisdom must be exercised in the appointment of teachers, and
just as far as possible those should be chosen who not only have
mastered the elements of botany, but have, by virtue of a broad
and deep training, an appreciation for more of the subject than
the mere minimum requirement of the class room.

The third problem which botany has been obliged to face in
the last few years is that of nature study. Every one must be
aware that the science has suffered at the hands of those who
have pleased to popularize botany at any cost, and at times even
to sacrifice truth. As a result the ugly but somewhat merited
name of nature-faker has arisen. Teachers of the general public
and of students in our public schools have deceived themselves
in the thought that knowledge is to be acquired by play, not work;
that the child who makes a conventionalized drawing of a butter-
fly is mastering a lesson in zoology, when in reality he is receiving
instruction in art or free-hand drawing; that the boys and girls who
plant beet seeds in the school garden are acquiring botanical
knowledge at the same time that they are receiving an elementary
lesson in agriculture.

I believe the botanical garden and museum, if wisely directed
and carefully arranged, may have a strong correcting influence
upon those who tend to misinterpret, wilfully or otherwise, natural

36 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

laws. Nature if left to itself provides for us a botanical garden
but with a very awkward arrangement. She seldom classifies,
points out or directs. People look with satisfaction on a host of
varied plants of which such a natural garden is made up, but
with enjoyment only. No information is offered and little or no
accurate knowledge is obtained. You who are able to present
to the general public such an extraordinary garden, in which the
visitors young and old alike are made acquainted with a most
remarkable collection of plants, should consider yourselves as
foremost among the teachers of botany, and your effort represents
no small directing factor in the dissemination of accurate informa-
tion about plants.

In passing I feel that I must call the attention of those con-
cerned to the fact that many of my students have spoken with
peculiar interest of their visits to the New York botanical and
zoological gardens. To be sure, weird plants and animals have
often been described to me—products of a fading memory and
active imagination—but they are none the less indicative of the
real interest excited in the visitor.

Finally, the methods employed in, and the conditions attendant
upon, graduate instruction and research present real problems,
and, in order that we may properly train the interested student
in advanced work so that we may have a steady procession of
competent botanists, and thus assure ourselves of the permanency
of the science, I believe we must turn more attention toward these
problems. I have time only to mention them here.

The graduate student is peculiarly sensitive to the conditions
attendant upon his work. A spirit of harmony among the mem-
bers of the department in which he labors inspires him with con-
fidence and enthusiasm, while on the other hand the evil effects of
contention and ultra-individualism are sooner or later to be
reflected in the graduate product.

There is need for a greater spirit of codperation among investi-
gators. We are too prone to look with pity from our field of
activity over to those who may be working as fertile a soil but with
different results.

There is need also for more thorough organization in botanical
research. Probably no one of us has escaped the experience of
reading articles from the pen of another author, which contain

CHIVERS: DIRECTING FACTORS IN TEACHING OF BOTANY 37

results identical with our own. Two have devoted their attention
to one problem. The time of one has been almost or entirely
wasted, and his work has been discounted. There is no doubt
that some of this confusion may be assigned to plagiarism, but
by far the greater part is due to a lack of intelligent organization
among researchers. Many of us have come to look with suspicion
upon our neighbor, and to conceal our product until we are entirely
certain that no man can borrow it.. Of what advantage it would
be to the science if each and every person engaged in botanical
research could have access to some common source of information
which should indicate the field of activities of the individual.
Then theft would be in the nature of an inexcusable misdemeanor,
and our attitude one toward another would rapidly change.

In concluding I may say that I am convinced that botany is
on trial at the present time in our educational system. It is a
comparatively young subject and has not as yet arrived at a
well-developed stature. Whether or not it will succeed is open
to serious question. We are told by some that botany will
prosper in so far as it is able to show its relation to the various
branches of industry. On the contrary I believe it will fail if
this be our shibboleth. The success of any subject cannot be
measured by the number of dollars and cents it can earn.

We have seen in recent years the decline of the study of Greek
and Latin, the reason most frequently given being that these
subjects have had no relation to the practical affairs of life. This
fallen position I venture to say is not permanent, and if we will
look into the future beyond this money-getting age we shall find
Greek and Latin restored to their proper position in our educa-
tional system. The restoration will be not on account of their
commercial value, but their importance per se.

It seems highly possible that botany may experience a similar
downfall unless those who have the interests of the science at
heart are willing to devote time and attention sufficient to guide
its progress. I believe the most potent guiding factors are those
which I have already attempted to point out: intelligent and ac-
curate instruction in our public schools; well-equipped botanical
gardens and museums; strong courses in foundational botany in
our colleges; a hearty spirit of codperation in our graduate depart-
ments; thorough organization in the field of research.

MY? 9) ~
u/hns, apr eda ir fa

hag
ie "Veen >

. afiMal?

i. ate tees
oT]

, hae
bh P.

Or hope We a 1 ay

He ial

“4

le
a

4
Pos4

SEGREGATION OF GENERA IN
LENTIBULARIACEAE

JoHN HENDLEY BARNHART

The New York Botanical Garden

The true bladderworts seem to have been overlooked by the
earlier botanists. All are small herbs; the European ones are
aquatics (a sadly neglected class of plants); and none are of the
slightest economic importance. Their discovery may be placed
with much definiteness in the last quarter of the sixteenth century,
for the species now. known as Utricularia vulgaris was described
and illustrated in the German edition of Lobel’s herbal, in 1581,
although it was not mentioned in the Latin edition published
five years earlier, in 1576. It may be remarked in passing that
Lobel’s crude wood-cut of 1581 is an excellent habit-sketch of the
plant; better, in fact, than any known to me in the numerous
elaborately illustrated works of the three following: centuries.
Six years later, in 1587, was published the name Lentibularia of
Gesner, derived from the lentil-like bladders overlooked by Lobel.

During the next century and a half the genus received scant
attention. A second European species, now known as Utricularia
minor, was distinguished, and Linnaeus, at the end of this period,
in 1737, changed the name of the genus to Utricularia; but in
1753, when he first used uniformly binary names, he recognized
only seven species. These agreed in having two stamens, a
single pistil, a two-parted calyx, a gamopetalous corolla with a
palate and spur, a one-celled ovary and capsule, and a free-central
placenta. And from that day to this, nearly every botanical
taxonomist has referred to Utricularia all plants possessing the
characters just mentioned, no matter how diverse they might be
in other respects nor how incongruous the result.

When I began to devote particular attention to this group of
plants, some years ago, it was soon manifest to me that their
classification was in the utmost confusion. Herbarium material

40 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

is often fragmentary, and no real progress was made until it was
discovered that certain of the more persistent structures could
be clearly correlated with the more delicate ones; so that, for
instance, it became possible in the absence of corollas to identify
material which without such correlation was not determinable.
In my arrangement of these plants I have emphasized what might
be termed ‘‘vegetative’’ parts of the inflorescence, but this is
because the characters drawn from these are readily demon-
strable, while correlated characters drawn from the flowers and
fruit are just as striking but more difficult to utilize in the study
of herbarium material. The characteristic corolla-forms, too, are
complicated, and often when the type is recognizable at a glance,
verbal description proves very elusive, and can not be succinct.

If my efforts shall aid in bringing order out of the present
chaos, it makes little difference to me what rank, whether generic
or subgeneric, is accorded to the groups I have come to recognize
as natural ones. For me the current genus Utricularia comprises
more than a dozen perfectly well-defined genera; but my aim is
to show that the groups exist in nature, not to quarrel with anyone
about what they shall be called.

A few words may not be out of place concerning those genera of
Lentibulariaceae that have hitherto been distinguished from
‘Utricularia. The most unrelated of these is Pinguicula. The
European species of the two genera are so different in appearance
that their affinity does not seem to have been recognized until
they were brought together in the Linnaean artificial system; then
it became evident that the characters possessed by them in com-
mon were not purely accidental, but of a fundamental nature.
Extension of our knowledge of the species of the world, however,
has in so far broken down the distinctions between Pinguicula
and the rest of the family, that I know of only two characters that
can be depended upon to distinguish this genus from the others.
One of these, purely vegetative, is the possession of true roots,
not otherwise known in the Lentibulariaceae; in the other genera,
however, other organs, sometimes leaves, sometimes stems, mimic
roots so successfully that it is not always easy to prove that they
are not what they seem. ‘The other definite character of Pingut-
cula, while it is found.in the inflorescence, does not reside in either
the flower or the fruit, but in the fact that the scapes are always

BARNHART: GENERA IN LENTIBULARIACEAE 4I

one-flowered (except in the rare cases of forking) and are truly
simple, being quite devoid of bracts; while in the other genera
the compound nature of the scape is always indicated by the pres-
ence of at least one bract, even when there is only a single flower.

The species of Pinguicula are remarkably uniform in habit.
Four very distinct types of corolla are to be found, and their
recognition furnishes an unquestionably natural method for the
arrangement of the species; for the present, however, even the
iconoclastic treatment here adopted leaves the genus Pinguicula
undisturbed.

The genus Genlisea differs from Utricularia as commonly
accepted in having the calyx 5-lobed instead of 2-lobed. Each
plant bears leaves of three kinds: ordinary foliage-leaves, root-
like subterranean ones, and ascidia of a peculiar type entirely
different from any of the bladders found in other genera.

Polypompholyx is the name that has been most commonly
applied to a small Australian genus characterized by four calyx-
lobes. .Two of these are antero-posterior, and are undoubtedly
true calyx-lobes; the two others are lateral and internal, and
more or less petaloid, and should perhaps be regarded morpho-
logically rather as specialized appendages of the calyx than as
true lobes. The genus is here called Cosmiza, a prior name applied
by Rafinesque to one of its species, although he knew nothing of
the peculiar calyx which furnishes the most distinctive generic
character.

The genus Biovularia is based upon a minute plant collected
many years ago in Cuba by Charles Wright, and is characterized
by two ovules, only one maturing, instead of the usually numerous
ovules and seeds of other Lentibulariaceae. It is an instance,
it is true, of extreme reduction, and may well be recognized as a
valid genus; but its relationship is extremely close with certain
species of the genus Ufricularia as here restricted, and it is far
less entitled to recognition than any of the other segregates here
distinguished. :

After excluding Pinguicula, Genlisea, Cosmiza, and Biovularia,
there is left in the family a vast assemblage of heterogeneous
elements hitherto retained in a single genus, Utricularia, which
it is here proposed to dismember. The collective genus may be
distinguished from the others by the combination of the following

42 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

characters: a compound (bracteate) inflorescence, several or usually
numerous ovules and seeds, and a persistent 2-parted calyx, so
deeply parted that the lobes are often referred to in descriptive
works as sepals. In all other characters, such as habit, foliage,
inflorescence, corollas, anthers, fruits, and seeds, the utmost
diversity prevails.

In segregation, the most useful characters are to be derived
from those structures which may be termed collectively the
vegetative appendages of the scape, all of them reduced foliar
organs, and may be distinguished as scales, bracts, and bractlets.
Of these, the bracts alone are invariably present, and of these
there is sometimes only one. Each pedicel is axillary to a bract,
“although when there is only a single flower its pedicel commonly
appears like a prolongation of the main axis of the scape, and the
rudimentary tip of the latter looks as if it were opposite to the
single bract.

The bracts may be either basifixed or basisolute. In the latter
case the bract is produced below the point of insertion into a
free lobe, more or less similar to and sometimes almost as large
as the portion above the point of insertion. At first sight this
character, so striking and not known to me outside of this family
of plants,’ would appear to be of primary importance in any scheme
of classification; but the Lentibulariaceae appear to have de-
veloped three very distinct types of basisolute bracts, and I have
come to regard the structure of the bract as less fundamental than
the presence or absence of bractlets.

In one type of basisolute bracts the free base is relatively short,
and may be compared to an auriculate base with the auricles
meeting below and fused along the line of contact; this type
occurs in Meloneura, Pelidnia, and Pleiochasia, and basisolute
bractlets always accompany the bracts. In the second type the
bracts are almost exactly peltate, the point of insertion being near
the middle; it occurs in Avesicaria and Setiscapella, and there are
no bractlets. In the third type the free portion consists of a
more or less membranous outgrowth, of irregular shape, extending
downward like an apron from the transverse line of insertion of
the bract; this occurs only in Vesiculina, and while it appears to

1A very similar structure has been described as occurring in Litanthus, a South
African genus of Liliaceae.

BARNHART: GENERA IN LENTIBULARIACEAE 43

be uniformly present in some species and absent in others, there
are species in which the free basal portion may be developed or
not, even in the case of two bracts on the same scape. It is
evident, therefore, that this third type of free base is of little
taxonomic significance.

The bractlets, when present, are always two to each pedicel,
opposite to each other, and lateral with respect to the median
bract. In Avanella they are borne distinctly above the base of
the very short pedicel, but distinctly below the calyx, and simulate
a pair of lateral exterior sepals. In all the other genera in which
they occur they are at the base of the pedicel. In most cases
they are inserted just above the bract, and more or less enfolded
by its base; but in at least one genus they are inserted on the
same line with the bract and are commonly more or less coherent
with it. There results a single three-lobed bract, but the bract-
lets always manifest their presence as distinct lateral lobes, and I
have never experienced any difficulty in deciding whether a bract
was actually without bractlets or had bractlets adnate to it.

Below the lowest bract the scape may be naked, that is, wholly
destitute of foliar organs, or may bear appendages for which the
word ‘‘scale’’ is in use, and is ordinarily appropriate. In some
cases the scales resemble the bracts so closely that one might
suppose them to be merely bracts in whose axils the pedicels had
failed to develop, but frequently there is a marked contrast
between the bracts and the scales. For instance, in Avanella
the bracts are basifixed while some or all of the scales are peltate.
In many species of Utricularia the so-called scales are developed
into large hollow floats, verticillate or subverticillate; indeed, these
conspicuous organs suggest themselves at once as a possible basis
for generic segregation. A study of the species bearing them
shows, however, that they differ from each other more widely than
from some of the species without floats, and if the ampulla-bearing
species are to be separated from Utricularia, a philosophic treat-
ment will require that they be distributed into several genera
rather than kept in one.

The calyx-lobes are usually nearly equal, the most marked in-
equality occurring in Meloneura, where the upper lobe is much
larger and is adnate to the base of the ovary. In texture they are
commonly herbaceous, but may be scarious, foliaceous, or even

44 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

petaloid. They may be but slightly enlarged and spreading
under the capsule or appressed to it, or markedly accrescent and
completely enclosing it, or even extending far beyond it like a
pair of valves.

The corolla is always strongly two-lipped, and spurred or rarely
only saccate at the base of the lower lip, but otherwise shows great
diversity. Each genus possesses its own characteristic type of
corolla, easily recognized at a glance when one has become familiar
with it, but sometimes difficult to define in words. The palate is
very different in different genera; two-lobed in some, nearly
hemispheric in others, helmet-shaped in Stomoisia; in Calpidisca
the limb is strongly reflexed from the aperture of the spur, the
palate consisting of a more or less thickened and sometimes
toothed ring along the line of reflexion; in Vesiculina the palate
is a prominent and divergently two-lobed sac involving essentially
the whole of the two lateral lobes of the lower lip; in Lecticula the
palate is nearly obsolete and the corolla is almost that of Pingut-
cula.

One of the noteworthy family characters commonly assigned to
the Lentibulariaceae is the possession of one-celled anthers. It is
probably true that the anthers are never two-celled with the cells
collateral, as is commonly the case in related plants; but through-
out the group with bractlets, the anthers are always more or less
strongly transversely constricted and consequently partially if
not completely vertically two-celled. This anther-structure de-
serves special study, particularly from the standpoint of its
developmental history. So, too, does the very peculiar anther-
structure of a small group of South American species, here referred
provisionally to Calpidisca, but probably worthy of generic rank
when better understood. In these, there is developed at the
summit of the filament a broad horseshoe-shaped membrane,
called for want of a better term a ‘‘connective,’’ bearing on its
inner edge two anther-cells, or perhaps a single strongly con-
stricted one.

The ovary, placenta, and stigma are very similar throughout
the family. So also is the capsule, although the method of
dehiscence may prove of some value in classification when known
for all species. The seeds present great variations, but these are
chiefly in the form and markings of the outermost seed-coat.

BARNHART: GENERA IN LENTIBULARIACEAE 45

Seed-characters have been made use of in so far as present know!-
edge permits, in the classification here proposed; but no genus
has been based exclusively, or even primarily, upon seed-charac-
ters, for these differ too strikingly in the case of some plants
evidently very closely related. As an example may be mentioned
the genus Meloneura, where one species has the seeds with a tuft
of simple hairs at each end, while those of the other species bear
scattered ‘‘glochidiate’’ (anchor-shaped) hairs, giving the seed
an appearance much like the statoblast of the fresh-water bryozoan
Cristatella.

In Small’s “Flora of Miami’’ and in the second edition of
Britton & Brown’s “Illustrated flora,’ both published in 1913,
my views upon generic segregation in this family were presented
to the botanical public as clearly as the limited scope of those
works would permit; but those views were not based upon a
study of North American species only, and it has seemed desirable
to place on record at least an outline of my more or less tentative
scheme of classification for the entire family. I have therefore
prepared the present discussion, and append diagnoses of each of
the sixteen genera I am now prepared to recognize, with brief
notes upon each genus, and a generic key.

CONSPECTUS: LENTIBULARTACEARUM
LENTIBULARIACEAE

Herbae annuae vel perennes, aquaticae vel terrestres, plerumque
hydrophilae. Folia alterna vel conferta vel rosulata, integra vel
dissecta, saepe radiciformia, interdum nulla. Inflorescentia sca-
posa, raro ramosa. Flores solitarii vel racemosi, interdum sub-
spicati, monoclini, zygomorphi. Calyx inferior, gamosepalus,
2—5-lobatus, persistens. Corolla hypogyna, gamopetala, antice
calcarata; limbus interdum subaequaliter 5-lobatus, sed saepissime
valde 2-labiatus; labium superius vero ex 2, inferius ex 3 lobis
coalitis formatum. Androecium staminibus 2 distinctis ad basin
corollae tubi insertis; filamenta plerumque arcuata, saepe praeterea
contorta; antherae uniloculares. Gynoecium ovario solitario uni-
loculare superiore; placenta libera centralis e basi enata; ovula
plerumque numerosa raro tantummodo 2; stylus plerumque
brevis crassusque, saepe subobsoletus; stigma valde bilabiatum,

46 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

labio anteriore lamelliforme, posteriore multo minore vel obsoleto.
Fructus capsularis, plerumque multiseminatus, irregulariter dehis-
cens vel valvatus vel indehiscens. Semina exendospermica;
embryo saepissime haud plane differentiatus.

1. Pinguicula L. Sp. Pl. 17. 1753. Herbae scaposae terrestres,
radicibus fibrosis. Folia rosulata; ascidia nulla. Scapus nudus,
uniflorus, circinatus. Calyx 5-lobatus, plus minus 2-labiatus;
labium superius 3-lobatum, inferius 2-lobatum. Corolla 5-lobata,
plus minus 2-labiata; labium superius 2-lobatum, inferius 3-
lobatum; tubus infra saccatus atque in calcar nectariferum con-
tractus. Antherae subglobosae. Capsula bivalvata. Semina nu-
merosa, oblonga, reticulata.

1.1 PINGUICULA subg. Isocopa. P. pumila Michx. Plant, half natural size.

2. PINGUICULA subg. PrlonopHyLLuM. P. vulgaris L. Plant, half natural size.

3. PINGUICULA subg. ORCHEOSANTHUS. P. caudata Schlecht. Plant, half natura
size.

4. PINGUICULA subg. TeMNocERAS. P. crenatiloba A. DC. a. Plant, half natural
size. 6. Flower, X 33.

Species typica, Pinguicula vulgaris L.

About 30 species, widely distributed throughout the northern
hemisphere, especially in America, and ranging southward along
the Andes to Patagonia.

1 All of the figures used to illustrate this paper are from drawings made several
years ago under my direction by Mr. Auguste Francois Théodore Victor Mariolle,
botanical artist for the university of Marseilles, 1892-1901, and for the New York
Botanical Garden, 1901-11.

BARNHART: GENERA IN LENTIBULARIACEAE 47

Four marked corolla-types may serve to distinguish as many
subgenera, or perhaps genera. Of these, the most distinct is
Temnoceras.

A. IsoLospA (Raf. pro gen.). Corollae lobi subaequales et
subaequaliter divergentes; calcar abrupte contractum et cum
tubo angulum validum formans.

B. PionopHyLLUM A.DC. Corollae limbus obliquus; lobi 2
superiores erectiores et plus minus coaliti, 3 inferiores explanati
et plus minus coaliti; tubus in calcar gradatim transiens.

C. ORCHEOSANTHUS A.DC. Corolla profunde 5-partita itaque
tubo subnullo; calcar pendens, lineare.

D. TEMNOCERAS (subgen. nov.). Corolla profunde bilabiata;
labium superius bidentatum, inferius divergente trilobatum; calcar
subcylindricum.

Isoloba comprises 4 species in the southeastern United States,
and about 6 in tropical America; there is only one in the Old World,
the little-known P. lusitanica L. The subgenus Brandonzia differs
only by its yellow corollas, and seems unworthy of taxonomic
recognition. Some of the species of Jsoloba have a prominent
acicular or even clavate palate, included in the throat, but in other
species the palate is much less distinct, while in some it is essen-
tially obsolete.

Pionophyllum comprises about I5 species, mostly European,
some of them ranging to the mountains of central Asia and northern
Africa, or to the northern parts of North America; while a few
are found in tropical America, and one as far south as Patagonia.

Orcheosanthus includes about 6 species, apparently, but future
study may show that the number is less, or that the fragmentary
material now preserved in herbaria represents a much larger
number. The range of variation is enormous, but how much is
seasonal, how much individual, and how much of taxonomic
importance, is at present mere guesswork. The group is wholly
confined to Mexico.

Temnoceras is based upon a single described species, a small
one of Mexico and Central America, Pinguicula crenatiloba.
Probably it will eventually be segregated into several species, but
the material now available is insufficient to accomplish this in a
satisfactory manner. The corolla-sinus is so deep that it extends
beyond the corolla-base and the lower lip is connected with the
upper one only by the spur; hence the name, which signifies
cleft spur.

48 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

2. Genlisea St. Hil. Voy. Distr. Diam. 2: 428. 1833. Herbae
scaposae terrestres, radicibus veris nullis. Folia suprema aeria,
rosulata, laminis expansis, infima subterranea, radiciformia, inter-
media ascidia formantia. Ascidia pedunculata, bullata, rostrata
tubo cylindrico, laminis 2 divergentibus contortis terminato, intus
elaborate armata. Scapus squamatus, bracteatus, uniflorus vel
pluriflorus; squamae et bracteae consimiles, basifixae; bracteolae
ad basin petioli 2, basifixae. Calyx 5-partitus; lobi subaequales,
sub capsula patuli. Corolla 2-labiata; labium superius subinte-
grum, inferius 3-lobatum. Antherae subglobosae vel oblongae.
Capsula globosa, saepe manifeste circumscissa.

Species typica, Genlisea aurea St. Hil.

5. GENLISEA. G. filiformis St. Hil. a. Plant, half natural size. 6. Scale, X 33-
c. Bract and bractlets, X 33. d. Flower, X 2. e. Corolla, X 2.

6. CosmizA. C. multifida (R. Br.) Barnh. a. Plant, half natural size. b. Base of
plant, X 23. c. Corolla, X 23. d. Fruit, X 33.

7. ARANELLA. A. fimbriata (H.B.K.) Barnh. a, }. Plants, half natural size.
c. Scale, X 8. d. Flower, with corolla and stamens removed, X 4. e. Bract, bract-
lets, and calyx, X 8.

About 15 species, of which 3 are African, I occurs only in Cuba
(where it has never been collected since its discovery by Charles
Wright many years ago), and the remainder are South American
(Brazil and Guiana).

In a few species (including the type species) the corolla is

BARNHART: GENERA IN LENTIBULARIACEAE 49

xanthic, in most itis cyanic. The spur is either conic or cylindric,
acute or obtuse; it is usually parallel with the lower lip, but in
one or two species is pendent.

3. Cosmiza Raf. Fl. Tellur. 4: 110. 1838. (Polypompholyx
Lehm. F 1844; Tetralobus DC. Mr 1844). Herbae scaposae
terrestres, radicibus veris nullis. Folia suprema aeria, rosulata,
laminis expansis, infima subterranea, radiciformia, intermedia
ascidia formantia. Ascidia pedunculata, bullata, erostrata. Sca-
pus esquamatus, bracteatus, uniflorus vel pluriflorus; bracteae
basifixae, minutae; bracteolae 2, consimiles. Calyx 4-partitus,
vel forsitan potius 2-partitus cum 2 appendiculis lateralibus in-
terioribus sepaliformibus, sub capsula patulus. Corolla profunde
2-labiata; labium superius parvum, inferius amplum, valde a
calcaris apertura reflexum; calcar conicum. Antherae_ subdis-
coideae. Capsula globosa.

Species typica, Cosmiza multifida comb. nov. (Utricularia multt-
jfida R. Br.; Cosmiza coccinea Raf.).

This curious genus is limited to western and southern Australia
and Tasmania. Australian botanists recognize only 2 species;
but the synonymy is large, and if there are actually only 2 valid
species they are both astonishingly variable. Careful field-study
is much needed; in default of this, I would estimate the probable
number of valid species represented in herbaria as 5 or 6.

4. Aranella Barnh. in Small, Fl. Miami 171. 1913. Herbae
scaposae terrestres, radicibus veris nullis. Folia rosulata, linearia,
saepe fugacia; ascidia nulla (?). Scapus squamatus, bracteatus,
uniflorus vel pluriflorus; squamae scariosae, fimbriatae, plerumque
peltatae; bracteae consimiles, sed basifixae; bracteolae 2, valde
majores, fimbriatae, supra basin pedicelli brevis et prope florem,
calyci lobos 2 laterales exteriores simulantes. Calyx genuinus
2-partitus; lobi fimbriati. Corolla valde 2-labiata; labii utrique
parvi; calcar conicum, cum labio inferiore parallellum. Antherae
sublobatae. Capsula subglobosa.

Species typica, Aranella fimbriata (H. B. K.) Barnh. (Utricularia
jimbriata H. B. K.).

This genus is monotypic, the single described species widely
distributed in tropical and subtropical America. In size, number
of flowers, and number and cutting of the scales, it is variable,
and it may be possible to recognize eventually several species.
By the blunder of a careless worker nearly 80 years ago, this plant
was erroneously referred to the very different genus here called

50 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Cosmiza; the error has been perpetuated in German botanical
literature, and even in Engler & Prantl’s Naturlichen Pflanzen-
familien, in 1893, the calyx and bracts of this species (as Poly-
pompholyx laciniata) are figured to illustrate the 4-parted calyx
of the Australian genus.

5. Meloneura Raf. Fl. Tellur. 4: 109. 1838. (Diurospermum
Edgew. 1848; Utricularia § Phyllaria S. Kurz. 1874.) Herbae
scaposae terrestres, stolonibus foliatis a basi scapi radiantibus,
radicibus veris nullis. Folia difformia, alia aeria laminis expansis,
alia subterranea, radiciformia et ascidiifera. Scapus esquamatus,
bracteatus, I—5-florus; bracteae basisolutae; bracteolae 2, con-
similes. Calyx 2-partitus; lobus superior multo major, ejus basi
ad basin ovarii adnata, inferior maturitate reflexus. Corolla
cyanica, valde 2-labiata; labium superius minimum, inferius
amplum, subplanum; palatum tantum convexitas; calcar tenue,
pendens. Antherae bilobatae. Capsula globosa. Semina ap-
pendiculata.

Species typica, Meloneura striatula comb. nov. (Utricularia
striatula Smith; Meloneura purpurea Raf.).

A small genus of about 6 species, confined to the tropics of the
Old World. One of the most distinct of the genera here recog-
nized; indeed, a synthetic type of mind is required to refer these
plants to Utricularia.

6. Pelidniagen.nov. (?Mezonula Raf. 1838.) Herbaescaposae
terrestres, ramulis brevibus radiciformibus et stolonibus tenuibus
foliatis a basi scapi radiantibus, radicibus veris nullis. Folia
difformia, alia aeria, rosulata, laminis expansis, alia subterranea,
radiciformia, ascidiifera. Ascidia utriculiformia, cum proboscide
unica plana glandulare. Scapus simplex vel saepe ramosus,
squamatus (vel in specie unica esquamatus?), bracteatus, I-
multiflorus; squamae mediofixae, extremo utroque acutae; bracteae
basisolutae; bracteolae consimiles sed minores. Calyx 2-partitus;
lobi herbacei, concavi, subaequales, sub capsula patuli. Corolla
cyanica, siccatione nigricans, 2-labiata; labium superius parvum,
inferius magno latius, valde a basi calcaris reflexum; calcar prope
basim late conicum, ad labium inferius non approximatum. An-
therae bilobatae. Capsula subglobosa, stylo persistente rostrata,
longitudine fissuris dehiscens, valvulorum extremitatibus semper
conjunctis. Semina polygonalia, reticulata.

Species typica, Pelidnia caerulea comb. nov. (Utricularia
caerulea L.).

Unfortunately, it is essential, in typifying this genus by U.
caerulea, to explain what is intended, as that name was applied

BARNHART: GENERA IN LENTIBULARIACEAE il

by Linnaeus to three different species, of which only one belongs
to the present genus. These three species were as follows:

1. A plant in Hermann’s herbarium, from Ceylon, apparently
the only actual specimen of U. caerulea ever seen by Linnaeus
before 1753. The specimen is still in existence, at the British
Museum (Nat. Hist.), and is here accepted as the type of the
Linnaean species, and of the present genus. This species has
been most generally known as U. racemosa Wall.

8. MELONEURA. WM. striatula (Sm.) Barnh. a,b. Plants, half natural size. C.
Bract and bractlets, X 8. d. Corolla, X 34. e. Fruit, x 33.

g. PELIDNIA. P. caerulea (L..) Barnh: <a,°b, ¢. Plants, half natural size. d. Scale,
X 32. ¢. Bract and bractlets, x 33. f. Flower, x 32.

10. PLEIOCHASIA. P. dichotoma (Labill.) Barnh. a. Plant, half natural size.
b. Bracts and bractlets, x 4.

2. A plant illustrated by Rheede, and confused with the pre-
ceding by Linnaeus, who cited Rheede’s illustration under U.

52 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ©

caerulea in 1753. This species is commonly and correctly known
as U. reticulata Smith; in the present treatment a Stomozisia.

3. A plant collected in India by Koenig, and placed by Linnaeus
in his herbarium to represent U. caerulea. It is the only specimen
of U. caerulea in the Linnaean herbarium, but it was not collected
until long after 1753, so can not by any possibility be regarded
as the type of the species. It is entirely different from both of
the preceding, although belonging in Stomoisia as here defined.
When Oliver monographed the Indian species of Utricularia, in
1859, he deliberately selected this Linnaean herbarium specimen
as the type of U. caerulea. He knew that it was not the original
U. caerulea of 1753, but believed that it represented a species
otherwise nameless, so instead of proposing a new name he quite
unwarrantably limited the Linnaean name to the wrong plant,
and as ‘‘U. caerulea L.”’ the species has been known ever since;
owing, in part, to the weight of Oliver’s “authority,” and in part
to the fact that no critical monographer has since reviewed the
Indian species. The oldest name of this species, overlooked both by
Oliver and the ‘‘ Index kewensis,”’ is Utricularia parviflora Buchan-
an, published by Smith in 1808, in his remarks upon the three
plants confused by Linnaeus under U. caerulea, at the same time
that he published U. reticulata! Smith discussed the whole
problem fully and wisely, and solved it correctly; it remained
for one of his fellow-countrymen, 50 years later, to go over the
ground independently and come to an erroneous decision that
introduced a regrettable element of confusion, and has resulted
in the misinterpretation of the Linnaean name for another half
century.

About 15 species of Pelidnia have been described, all from trop-
ical Asia and Australia; another, apparently not yet described or
named, occurs in tropical Africa. Most if not all of the species turn
blue-black in drying, and this has suggested the name Pelidnia,
from a Greek adjective signifying livid. Meionula of Rafinesque
was based upon U. minutissima Vahl, a doubtful species, probably
belonging to the genus Pelidnia as here defined, but it has seemed
better to give the genus a new name than to use for it one of
doubtful applicability.

7. Pleiochasia (Kam.) gen. nov. (Utricularia § Pleiochasia
Kam. 1893.) Herbae scaposae terrestres, radicibus veris nullis.

BARNHART: GENERA IN LENTIBULARIACEAE 53

Folia suprema aeria, rosulata, laminis expansis, infima subterranea,
radiciformia, intermedia etiam radiciformia, sed ascidiifera. As-
cidia compresso-ovoidea, margine dorsale in rostro terminante,
margine ventrale carinata. Scapus esquamatus, bracteatus, 1-4-
florus; bracteae oppositae vel verticillatae, basisolutae; bracteolae
2, consimiles. Calyx 2-partitus; lobi herbacei, concavi, subae-
quales, capsulam amplectentes sed non excedentes. Corolla
cyanica, valde 2-labiata; labium superius parvum, inferius am-
plum, expansum, planum vel parum reflexum; palatum parvum,
dentatum; calcar cylindricum obtusum. Capsula subglobosa, stylo
persistente brevirostrata.

Species typica, Pleiochasia dichotoma comb. nov. (Utricularia
dichotoma Labill.).

This genus, as here defined, comprises about 20 species, all
natives of Australia or New Zealand. It is undoubtedly a natural
group, but contains rather diverse elements; so much so that
Kamienski, when he proposed the section Pleiochasia, proposed
another section (Macroceras) here provisionally combined with it.
Most of the species are poorly represented in European and
American herbaria, and a careful study of the group might result
in the segregation of other genera from this one.

8. Orchyllium gen. nov. Herbae scaposae epiphyticae vel ter-
restres, ramulis brevibus radiciformibus et stolonibus foliatis a basi
scapi radiantibus, radicibus veris nullis. Folia difformia, alia
aeria, laminis expansis, alia subterranea, radiciformia, ascidiifera.
Ascidia minuta, ovoidea, ore prope basin, saepe cum projectionibus
duobus pediculum utrimque praeterientibus. Scapus squamatus,
bracteatus, 1-multiflorus; squamae plures, basifixae, saepe foli-
aceae; bracteae basifixae, saepe subfoliaceae; bracteolae consimiles.
Calyx 2-partitus; lobi plani, ad basin saepe truncati vel cordati,
tenuiter venosi, virides vel plus minus petaloidei, accrescente val-
vati et conjuncte adpressi et capsulam includentes. Corolla cyanica,
valde 2-labiata; labium superius amplum, subplanum, inferius
amplum, plerumque carinatum in lineam mediam; calcar ad basin
saccatum, distaliter tenuius, saepe sursum curvatum. Antherae
valde bilobatae.

Species typica, Orchyllium alpinum comb. nov. (Utricularia
alpina Jacq.).

This genus comprises about 10 or 12 species, several of them
among the largest in the family, natives of the American tropics.
Owing to their epiphytic habit and orchid-like appearance (whence
the name Orchyllium), they are often grown with orchids, and have

54 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

been repeatedly introduced into cultivation; yet no one seems to
have given critical study even to these cultivated plants.

The African analogues of Orchyllium are confined to the moun-
tains of the mainland and islands of the gulf of Guinea; two species,
Utricularia Mannii Oliver and U. bryophila Ridley, have been
described, and both are recognized in the ‘Flora of tropical
Africa,’’ but they are probably not distinct. All the material of
both so-called species in the herbaria of the world could probably
be mounted on a single sheet of standard size without over-
lapping. Enough is known of this group to indicate a valid genus,
but not enough to characterize it properly; for the present it is
referred here, but no attempt has been made to include it in the
characterization of the genus Orchyllium.

9. Stomoisia Raf. Fl. Tellur. 4: 108. 1838. (? Trixapias Raf.
1838; ? Askofake Raf. 1838; Neltpbus Raf. 1838; Enskide Raf.
1838; Personula Raf. 1838.) Herbae scaposae terrestres, ramulis
brevibus radiciformibus et stolonibus tenerrimis foliatis a basi scapi
radiantibus, radicibus veris nullis. Folia difformia, alia erecta et
viridia, linearia vel sublinearia, alia subterranea et radiciformia,
ascidiifera. Ascidia minuta, valde reducta, rostrata. Scapus
erectus vel flexuosus vel tortilis, squamatus, bracteatus, I—multi-
florus; squamae basifixae; bracteae basifixae; bracteolae consimiles
sed angustiores interdum filiformes. Calyx 2-partitus; lobi tenues,
venosi, superior plerumque major, capsulam arcte amplectentes,
saepe accrescente valvati. Corolla xanthica vel cyanica, profunde
2-labiata; labium superius distincte unguiculatum, inferius gale-
atum, cum margine plus minus expanso; palatum praeter galeam
nullum; calcar conicum, pendens. Antherae bilobatae. Capsula
subglobosa, stylo persistente rostrata, calycis lobis arcte inclusa.
Semina subglobosa vel prismatica, areolata vel reticulata.

Species typica, Stomoisia cornuta (Michx.) Raf. (Utricularia
cornuta Michx.).

This genus, of about 50 or more species, is widely distributed in
southern Asia, in Africa and Australia, and in eastern North and
South America; it is lacking in Europe, northern Asia, and through-
out the Andean region. With the exception of Utricularia and
perhaps Calpidisca, it is the largest genus of the family. It is
strikingly characteristic in habit, and usually readily recognizable
at a glance. Most of the species have yellow corollas, strongly
laterally compressed, and the galeate lower lip is a prominent
feature in all.

BARNHART: GENERA IN LENTIBULARIACEAE 55

10. Calpidisca gen. nov. MHerbae scaposae terrestres, ramulis
brevibus radiciformibus et stolonibus tenerrimis foliatis a basi
scapi radiantibus, radicibus veris nullis. Folia difformia, alia
erecta et viridia, alia subterranea et radiciformia, ascidiifera.
Ascidia urceolata, margine plus minus bilabiato et fimbriato.

II. ORCHYLLIUM. O. alpinum (Jacq.) Barnh. Plant, half natural size.

12. Stomorsta. S. cornuta (Michx.) Raf. a. Plant, half natural size. 6. Bract,
bractlets, and calyx, X 14. c. Flower, X 2. d. Bladder, X 10.

13. CALprpiscA. C. denticulata (Benj.) Barnh. a, 6. Plants, half natural size.
c. Flower, X 33. d. Fruit, X 33. e. Bladders, X Io.

Scapus interdum ramosus, squamatus, bracteatus, I—multiflorus;
squamae basifixae; bracteae basifixae; bracteolae consimiles, saepe

56 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

ad bracteam adnatae, itaque bracteam tripartitam vel trifidam
vel divergente tridentatum formantes. Calyx 2-partitus; lobi
concavi, ad capsulam non adpressi. Corolla cyanica, profunde
2-labiata, marcescens et persistens; labium superius exunguicu-
latum, inferius cum limbo a margine calcaris oris abrupte reflexo;
palatum, margine crasso calcaris oris excepto, nullum; calcar cum
limbo parallelum vel breve et saccatum. Antherae bilobatae.
Capsula globosa, stylo persistente rostrata.

Species typica, Calpidisca capensis comb. nov. (Utricularia
capensis Spr.)

There are about 60 species of this genus, mostly confined to
tropical regions and extratropical South Africa. In many of the
species the leaves and bladders are evanescent, disappearing before
the flowers are developed; indeed, in some of the species the
leaves and bladders are quite unknown. In all species in which
the bladders are known, they are distinctly urceolate, and the
name Calpidisca is derived from two Greek words meaning urn
and disc. A considerable proportion of the described species,
especially the American ones, have been collected only once or
twice, and the group needs much critical study. This is par-
ticularly true of several Brazilian species with hippocrepiform
connectives, otherwise more or less intermediate between Cal-
pidisca and Orchyllium, and doubtless eventually deserving generic
segregation.

The type species and several related ones were beautifully
figured in the 28th volume of ‘‘Hooker’s Icones plantarum”’
(pl. 2793-2707); the illustration presented herewith is of a Mexi-
can species, Calpidisca denticulata comb. nov. (Utricularia denti-
culata Benj.).

11. Avesicaria (Kam.) gen. nov. (Utricularia § Avesicaria
Kam. 1893.) Herbae scaposae aquaticae, ad rupes in aquo
fluitante per tenacula radiciformia adhaerentes, radicibus veris
nullis. Scapus squamatus, bracteatus, 2—multiflorus; squamae
peltatae, saepe cum ramis tenuibus natantibus axillaribus, folia
tenuiter dissecta ferentibus; bracteae peltatae; bracteolae nullae.
Calyx 2-partitus; lobi concavi, basin capsulae amplectentes.
Corolla valde 2-labiata; palatum semilunare, ad basin labii inferii;
calcar saccatum. Placenta hemisphaerica, superficiei anteriore
convexa ovulifera. Capsula subglobosa, stylo persistente apicu-
lata.

Species typica, Avesicaria neottioides comb. nov. (Utricularia
neottioides St. Hil. & Girard).

BARNHART: GENERA IN LENTIBULARIACEAE 57

Several species constitute this genus, all in Brazil, except one in
tropical Africa. Its habit is the most noteworthy characteristic
separating it from Setiscapella, although the corolla and placenta
are very different, if the published descriptions are to be trusted.

14. AVESICARIA. A.sp.1 Plant, half natural size.

15. SETISCAPELLA. S. subulata (L.) Barnh. a,b. Plants, half natural size. c.
Scale, X 4. d. Bract, X 4. e. Corolla, x 4.

16. Lecticuta. L. resupinata (B. D. Greene) Barnh. a. Plant, half natural size.
b. Bract, X 4. c. Flower, X 13.

17. BrovuLartaA. B. olivacea (Wright) Kam. a, 0. Plants, xX 13. c. Base of
scape, showing bracts and buds, X 10. d. Corolla, split open on one side, X 8.

12. Setiscapella Barnh. in Small, Fl. Miami 170. 26 Ap 1913;
in Britt. & Brown, Ill. Fl. ed. 2. 3: 230. 7 Je 1913. Herbae
scaposae terrestres, ramulis brevibus radiciformibus a basi scapi
radiantibus, radicibus veris nullis. Folia difformia, alia erecta

1 The species illustrated is in various herbaria under the manuscript name Utricularia
Glaziouana Kam., and has been mentioned in print as U. Glazioviana Warm. (Mém.
Soc. Bot. Fr. 3: 512), but I am not aware that any description of it has been published.

58 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

et viridia, saepissime evanescentia, alia subterranea et radici-
formia, ascidiifera. Ascidia minuta, apice 2-cornuta. Scapus
squamatus, bracteatus, I—multiflorus, saepissime maturitate an-
fractus; squamae et bracteae peltatae, scariosae; bracteolae nullae.
Calyx 2-partitus; lobi scariosi, valde longitudinaliter pluri-costati
sub capsula patuli vel basin capsulae amplectentes. Corolla
xanthica, valde 2-labiata; labium superius subplanum amplum,
inferius amplum, plerumque valde divergenterque lobatum; pala-
tum saepissime prominens et 2-lobatum; calcar ad basin conicum,
distaliter tenue, vel omnino saccatum. Antherae subglobosae.
Capsula globosa, stylo persistente apiculata. Semina prismatica,
reticulata.

Species typica, Setiscapella subulata (L.) Barnh. (Utricularia
subulata L.).

Of the dozen species comprising this genus, nearly all are
American, but one occurs in Africa, and at least two in the Hima-
layas. Its wiry, zig-zag scapes, peltate scales and bracts, and
scarious calyx-lobes are very characteristic. In most of the
species leaves and bladders are rarely seen.

13. Lecticula Barnh. in Small, Fl. Miami 170. 26 Ap 1913; in
Britt. & Brown, Ill. Fl. ed. 2. 3: 230. 7 Je 1913. Herbae scapo-
sae, ramulis radiciformibus foliatis normaliter submersis, radicibus
veris nullis. Folia alterna, saepissime 3-partita; lobus medius
erectus; lobi laterales capillares radiciformesque, ascidiiferi. As-
cidia minuta, rostrata. Scapus semper 1I-florus, pedicello con
scapo continuo; squamae verae nullae; bractea solitaria, basifixa,
squamam simulans amplexicaulis tubularisque, margine libero
truncato, plus minus 2-inciso; bracteolae nullae. Calyx 2-partitus;
lobi concavi, herbacei, ad capsulam adpressi. Corolla valde 2-
labiata; labii subintegri; palatum tantum convexitas; calcar sub-
conicum, obtusum. Antherae subglobosae. Capsula globosa.

Species typica, Lecticula resupinata (B. D. Greene) Barnh.
(Utricularia resupinata B. D. Greene).

Besides the type species, which occurs locally throughout the
eastern parts of Canada and the United States, only one other
has been described, Lecticula Spruceana comb. noy. (Utricularia
Spruceana Benth.), a native of eastern Brazil.

14. Biovularia Kam. Zap. Novoross. Obtsch. Est. 15': 204.
1890. Herbae minutae aquaticae. Folia alterna, capillariter
partita, ascidiifera. Ascidia birostrata. Scapus esquamatus,
bracteatus, 1~3-florus; bractea infima ad caulem proxima; bracteae
basifixae; bracteolae nullae. Calyx 2-lobatus; lobi subaequales.

BARNHART: GENERA IN LENTIBULARIACEAE

Corolla xanthica, hyalina, valde 2-labiata; labia integra; pala-
tum tantum convexitas; calcar saccatum. Antherae subglobosae.
Ovarium 2-ovulatum. Capsula (achenium) globosa, I-seminata,

indehiscens.

Species typica, Biovularia olivacea (Wright) Kam. (Utricularia

olivacea Wright).

The minute plants upon which Kamienski based this genus were
collected in Cuba by Charles Wright many years ago.

“oN be
4
| a Ab
S\N
SIGS @ > < / :
SHES A ER AUS AL BU uy, Ba
ay SEEN Se SS hy \WK Sy EZ Ra aty J
: : BEN ely
ASR NY
le? awed ae ‘S\ Wy
NeW at RN
t PAWN AS My Y
Mee
ig
WO
SW
SVL
ay

= . : ‘ Nw
ei. \Ss SS MH
tae \ =

18. UTRICULARIA. U.macrorhiza LeConte. Plant, one third natural size.

species has not been rediscovered in Cuba, but that since described
from Brazil by Warming as Utricularia minima is either identical
or very closely related. There are few smaller flowering plants.

The African species called Biovularia cymbantha by Kamienski
has nothing to do with this genus; it is a true Utricularia.

60 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

15. Utricularia L. Sp. Pl. 18. 1753... (Lentibularia Hill, 1756;
Xananthes Raf. 1838; Hamulia Raf. 1838; Lepiactis Raf.
1838; Megozipa Raf. 1838; Trilobulina Raf. 1838; Plesisa Raf.
1838; Plectoma Raf. 1838.) Herbae aquaticae, caulibus sub-
mersis foliosis, radicibus nullis. Folia alterna, dissecta, interdum
radiciformia, sessilia et profunde 2-8-partita, itaque simulate

7 4

20 | l

19. Urricutarta. U. macrorhiza LeConte. a. Scape, with flowers, half natural
size. 6. Scape, with fruit, half natural size.

20. Urricutarta. U. pumila Walt. Plant, half natural size.

21. UrricuLtarta. U. minor L. Plant, half natural size.

opposita vel verticillata; segmenti dichotome vel pinnate dis-
secti, aliquot vel omnes ascidiiferi. Ascidia 2-rostrata, rostris saepe
setiformibus et plus minus dissectis. Scapus squamatus vel esqua-
matus, I—multiflorus; squamae alternae, basifixae, vel interdum
subverticillatae vel verticillatae et ampulliformae; bracteae basi-
fixae, interdum auriculatae; bracteolae nullae. Calyx 2-partitus;
lobi concavi, herbacei. Corolla valde 2-labiata; palatum saepis-
sime prominens, 2-lobatum; calcar subconicum vel saccatum.

BARNHART: GENERA IN LENTIBULARIACEAE 61

Antherae subglobosae. Capsula globosa. Semina plus minus
peltata, margine alata vel non alata.

Species typica, Utricularia vulgaris L.

In the present revision about 75 species are left in Utricularia,
and the genus as here defined is of world-wide distribution, one or
more species being found in almost every region where quiet fresh-
water conditions occur, except in certain oceanic islands. Six or
eight subgenera might be distinguished, and some of these even-

22. UTRICULARIA. U. hydrocarpa Vahl. a. Plant, half natural size. 6. Flower,
‘with bract,. 033... c. Fruit, X 33.

23. UTRIcULARIA. U. inflata Walt. Plant, one fourth natural size.

24. VESICULINA subg. Hyprion. V. cucullata (St. Hil.) Barnh. a. Plant, half
natural size. 6. Corolla, X 23. c. Bladder, X 8.

tually will deserve recognition as genera. The most noteworthy,
perhaps, is Akentra Benj., with two species, one in tropical America,
the other in tropical Africa; it is not spurless, as supposed by the
author of the name, but enough is known of it to show the incon-
gruity of its position in Utricularia. The other ampulla-bearing
species represent several good subgenera, if not genera; and the
long-styled, red-flowered species of tropical America may deserve
generic recognition. But the treatment of these groups is deferred
until another time.

62 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ;

16. Vesiculina Raf. Fl. Tellur. 4: 109. 1838. Herbae aquati-
cae, caulibus submersis, verticillate ramosis, ramis verticillate vel
opposite decompositis. Folia vera nulla. Ascidia terminalia
ad ramulos, ore nuda vel cum solitaria media pubescente
proboscide. Scapus esquamatus, bracteatus, 1—4-florus; brac-
teae basifixae vel simulate basisolutae; bracteolae nullae. Calyx

25. VESICULINA subgen. PEMPHIGINA. V. purpurea (Walt.) Raf. a. Plant, half
natural size. 6. Corolla, X 2. c. Bladder, xX 8.

2-partitus; lobi concavi, herbacei. Corolla cyanica, valde 2-
labiata; labium superius non lobatum, inferius 3-lobatum, lobis
lateralibus saccatis et palatum prominentem 2-lobatum formanti-
bus, lobo medio plano, inconspicuo. Antherae subglobosae.
Capsula globosa. Semina tuberculata.

Species typica, Vesiculina purpurea (Walt.) Raf. (Vesiculina
saccata Raf.; Utricularia saccata Le Conte; .U. purpurea Walt.).

Superficially bearing a close resemblance to Utricularia, this
group of species is really very distinct. The verticillate branches,
terminal bladders, and prominent palate involving both lateral
lobes of the lower lip of the corolla, are peculiarities not found
elsewhere in the family. Two subgenera may be recognized, as
follows:

BARNHART: GENERA IN LENTIBULARIACEAE 63

A. PEMPHIGINA subgen. nov. Corollae labia lata; ascidii os
nudum.

B. Hyprion subgen. nov. Corollae labia angusta; ascidii os
proboscidiferum.

The genus, of about 8 species, is known certainly from the New
World only; but it is not unlikely that Utricularia tubulata F.
Muell., of Australia, will be found to belong here.

Vesiculina, as published by Rafinesque, was a very unnatural
grouping of diverse elements, and it is only by accepting the
first species named by him as the type of his genus that his name
can be made use of here. Pemphigina is the typical subgenus,
with the same type species as Vesiculina; the type of the subgenus
Hydrion is Vesiculina cucullata comb. nov. (Utricularia cucullata

St. Hil.).

GENERA EXCLUDENDA

MIcRANTHEMUM Michx. was considered by St. Hilaire & Girard
(1838) to be intermediate between Lentibulariaceae and Scrophu-
lariaceae. No one has ever definitely referred it to the former
family, and it is now universally placed in the latter.

BENJAMINIA Mart. (Quinquelobus Benj.) was proposed in 1847 as
a new genus of Lentibulariaceae. It was short-lived, however, for
a year and a half later Bentham called attention (Lond. Jour. Bot.
7: 567) to the fact that it was a mixture of three genera belonging
to two families, and that no portion of the mixture belonged in
the Lentibulariaceae. The type species is probably referable to
Myriophyllum.

ByBLIs Salisb. was referred to the Droseraceae when first de-
scribed (1808), and left there by all subsequent authors for nearly
acentury. In 1901, F. X. Lang published a study of the Drose-
raceae, definitely excluding Byblis from that family, and suggesting
(owing to a similarity of certain epidermal appendages to those of
Pinguicula!) a possible relationship to Lentibulariaceae. Follow-
ing up this suggestion, Engler, in the third edition of his ‘‘ Syllabus ”
(1903) and in succeeding editions, has definitely referred Byblis to
Lentibulariaceae, creating for it a subfamily Byblidoideae, differ-
ing from the rest of the family in all its essential characters. The
genus appears to me to be as closely related to twenty or more
other families as to Lentibulariaceae; it is probably worthy of
recognition as the type of a distinct family, related (as suggested by
Diels, in 1906, in his monograph of the Droseraceae for Engler’s
‘‘Pflanzenreich’’) to the Pittosporaceae, and very far indeed re-
moved from the Lentibulariaceae.

CLAVIS ANALYTICA GENERUM LENTIBULARIACEARUM

Scapus ebracteatus; id est, inflorescentia simplex.
Scapus bracteatus; id est, inflorescentia composita.
Calyx 5-partitus.
Calyx 4-partitus.
Calyx 2-partitus.
Bracteclae 2, interdum plus minus cum bractea coalitae.
Bracteolae supra basin pedicelli, sepala lateralia ex-
teriores simulantes.
Bracteolae ad basin pedicelli.

Calycis lobi valde inaequales, superior major et
ad ovarium adnatus; bracteae et bracteolae
basisolutae.

Calycis lobi subaequales, liberi.

Bracteae et bracteolae basisolutae.

Bracteae alternae; squamae plures.

Bracteae oppositae vel verticillatae;

squamae nullae.
Bracteae et bracteolae basifixae.

Calycis lobi scariosi vel foliosi vel peta-
loidei, capsulam amplectentes;
ascidii ovoidei, rostrati.

Corollae labia subplana; palatum
prominens.

Corollae labium inferius galeatum;
palatum praeter galeam nullum.

Calycis lobi herbacei, capsulam non

amplectentes; corollae labium inferius
a margine calcaris oris abrupte re-
flexum; ascidii urceolati, plus minus
bilabiati.
Bracteolae nullae.
Corollae labium inferius cum lobis lateralibus non
saccatis vel nullis; rami alterni.
Bracteae squamaeque basisolutae vel peltatae.
Plantae aquaticae, ad rupes per tenacula
adhaerentes; placenta hemisphaerica.
Plantae terrestres; placenta subglobosa.
Bracteae basifixae; squamae basifixae vel nullae.
Bracteae tubulares; flos solitarius.
Bracteae planae vel concavae; flores saepis-
sime plures.
Ovula 2; semen I.
Ovula et semina pluria, saepissime
numerosa.
Corollae labium inferius cum lobis lateralibus saccatis;
rami oppositi vel verticillati.

10.

It.
12.

14.

15.

16.

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

PINGUICULA,

. GENLISEA.

COSsMIZA,

ARANELLA.

. MELONEURA.

PELIDNIA.

PLEIOCHASIA.

. ORCHYLLIUM.

. STOMOISIA.

CALPIDISCA.

AVESICARIA.
SETISCAPELLA.

LECTICULA.

BIOVULARIA.

UTRICULARIA.

VESICULINA.

OBSERVATIONS ON THE FLORA OF MAMMOTH
CAVE, KENTUCKY!

RICHARD ELLSWORTH CALL
DeWitt Clinton High School, New York City

In presenting these notes it is desired that they be considered
only a preliminary account of the plants of the great underground
world of Kentucky.

Packard, Putnam, and Hubbard, and later Eigenmann, who has
almost compelled us to believe that the blind fishes really see,
have well presented the animal side of the Cavern’s life. Your
relator has added some twenty additional species, mostly new,
described by specialists and to be found in the accompanying -
bibliography.’

Thanks to the painstaking interest of Dr. Roland Thaxter, his
careful study of the more difficult cryptogamic material collected
by me has added very much to our knowledge of cave forms.

Mammoth Cave underlies some 2,500 square acres of region and
the avenues that have been mapped extend over a distance of more
than 160 miles. This great distance is disposed in three vertical
series or layers, determined by the drainage levels of former
geological times. From the surface to a depth of some 225 feet
below it these connecting avenues occur. Its greatest depth
is determined by the present level of the Green River on the left
bank of which the cave is situated. The depth of the canon of
Green River marks the extreme depth of the cave.

It is, of course, to be fully understood that the total absence of
light precludes the possibility of chemic or actinic rays, and there-
fore all plant forms that possess chloroplasts are absent. The
flora is entirely saprophytic.

1 Abstract.

2 Call, R. Ellsworth. Note on the flora of Mammoth Cave, Kentucky. Jour.
Cincinnati Soc. Nat. Hist. 19: 79-80. Mr 1897.

Call, R. Ellsworth. Some notes on the flora and fauna of Mammoth Cave. Am.
Naturalist 31: 377-392. pl. ro-rz. My 1897.

Hovey, Horace C., & Call, Ellsworth R. The Mammoth Cave of Kentucky.
8vo, cloth, Louisville, 1897. John P. Morton & Co. A completely revised and better
illustrated edition appeared in 1912.

Hovey, Horace C., & Call, Richard Ellsworth. Bibliographie chronologique and
analytique de Mammoth Cave, Kentucky (Etats-Unis d’ Amérique). Spelunca
Bulletin et Mémoires de la Société de Spéléologie g: 191-237. Jl 1914.

6 65

66 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The distribution of the plant forms is exceedingly interesting.
It seems to be determined by the accidents of visitation. These
may be classified somewhat as following: (a) Visitors carrying
spores on clothing or on staffs and other impedimenta. (0b) By
the very few cave insects that travel widely, such as Anophthalmus.
(c) By the bats, which enter by the hundreds of thousands in
the late fall for hibernation purposes. (d) By the migrations of
the blind rat, Neotoma.

The first of these causes relates only to the distribution along
such avenues as are exhibited to visitors and is, therefore, of very
definite application. The others are all of indefinite operation,
may be continuous or discontinuous and are by no means constant.
It is well to keep these facts in mind as aiding to explain certain
fitful seasons of abundance or scarcity. All but two of the plants,
Mucor Mucedo and Laboulbenia subterranea have been found only
along the paths frequented by sight-seers. This Mucor occurs
wherever there is sufficient moisture and food supply. The second
form has been found thus far only on dead Anophthalmz, the blind
cave beetle. This is a most instructive fact and seems to justify
the conclusion that prior to the advent of man the cave was
practically devoid of plant life.

There are no representatives of the rusts, smuts, and mildews
among the forms discovered. These forms are entirely parasitic
on the higher forms of plants, the chlorophyll-bearing species.
No plant containing a single chloroplast has been discovered over
a study period of some five years. Diatoms alone have been
discovered in the plankton of Echo River and the Dead Sea. Nor
did the microscope reveal a single pyrenoid in the only diatom
represented—a transparent Navicula for which I have not found
a specific name. Many specimens were examined.

The underground rivers and smaller streams are fed by “‘sinks”’
or depressions of sometimes very great extent. They are caused
by the solution of the underlying St. Louis oolitic limestone and
the falling in of the superposed Chester sandstone—which together
constitute the simple geology of the region. These sinks are
mentioned thus particularly because, (a) In the waters that pass
through them to the cave many fungus spores must enter, and
(b) It would seem to explain the presence of Navicula in the
plankton.

At the several lunching stations food in abundance occurs on

CALL: OBSERVATIONS ON FLORA OF MAMMOTH CAVE 67

the rejectamenta which is often covered with certain low forms of
saprophytic plants. No less than six forms, distributed in as
many genera, are found in Washington Hall alone—the usual
luncheon stations for parties on the Long Route. These occur
indifferently on fragments of ham, chicken bones, and beef, while
the plant-using varieties are found on the fragments of bread and
other cereal products. For many years past the cave rats and
certain insects visit this section, attracted by the richness of the
food supply; this has caused this particular locality to become a
center of distribution for these plant forms. But, it is to be
noted, without exception all are plants of the outer world and
none are distinctively of cavernicolous origin. The introduction
by means of lunch baskets, clothing, staffs, timbers, etc., is too
obvious to need mention.

Briefly stated, the following conclusions have been reached
regarding the Cave’s flora. (a) Only two forms are to be regarded
as strictly cavernicolous. They are particularized below. (0)
Many are curiously modified both in habit and appearance by
peculiar conditions of environment, though the conditions are
very stable. (c) There are no seasonal or sporadic exhibitions of
plant life. The uniform temperature, of about 54 degrees F. and
the abundant supply of moisture are stable conditions: to these
the plant life is now well adjusted. (d) All the plants except
Coprinus micaceus, Fomes applanatus, and Rhizomorpha molinaris
are microscopic. (e) All are saprophytes, two being sarcophytes.

The following annotated list comprises all that is known of the
species inhabiting the cave. The list includes 13 genera and 15
species.

COPRINUS MICACEUS Bull.

River Hall and on the shore of the Dead Sea only. Groups
of several individuals have been taken along River Hall, near
the boat landing, and at the Cascades near the River Styx.
A new fly, Limosina stygia Coq. was discovered by the author
in a cluster taken on the River Styx. The toadstool is very
often found deliquesced.

FOMES APPLANATUS Pers.

Found in the Labyrinth, attached to old timbers and curiously
modified into cylindrical and ram’s-horn-like objects, some of
them more than ten inches in length. Introduced from with-
out the cave.

68 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

RHIZOMORPHA MOLINARIS Pers.

In the Mammoth Dome, on old timbers. A very peculiarly
modified species, some specimens being many-branched, others
cylindrical, and often ten inches in length. A large mass of
these plants on being accidentally shaken exhibited brilliant
phosphoresence.

CYATHUS VERNICOSUS (Bull.) DC.

A “bird’s nest”? fungus common on old timbers in the Mam-
moth Dome has been identified as being this cosmopolitan form.
It appears to be a poorly developed visitor from the outer
world.

Mucor Mucepo L. ;

Growing abundantly and sometimes covering areas of thirty
square feet and hanging in great festoons at the Steeps of
Time, River. Hall, and on the timbers around the Bottomless Pit.

MICROASCUS LONGIROSTRIS Zukal.

On rejectamenta in Washington Hall and also in Audubon
Avenue.

ZASMIDIUM CELLARE Fr.

At the top of the Corkscrew, in the Main Cave, on the head
of an old barrel, which it entirely covered with a dense brown
coating. Probably introduced from without, with the host.

GYMNOASCUS SETOSUS Eidam.

On sticks, bread, etc., in Washington Hall. This locality is the

Cave’s dining room.
SPOROTRICHUM DENSUM Link.
SPOROTRICHUM FLAVISSIMUM Link.

Both species occurred on dead beetles (Anophthalmus) in
Washington Hall.

LABOULBENIA SUBTERRANEA Thaxter.

Found only on dead Anophthalmt, particularly in the neigh-
borhood of Annette’s Dome.

LABOULBENIA sp.

Numerous specimens on the dung of bats in Audubon Ave.

and Rafinesque Hall.
COEMANSIA sp.
PAPULOSPORA sp.
BOUDIERA sp.

The paucity of material precludes any specific reference of
these three forms.

OBSERVATIONS ON INHERITANCE OF SEX-RATIOS
IN MERCURIALIS ANNUA

CECIL YAMPOLSKY

Columbia University

The discovery of the sex-chromosomes (so-called) in animals
has led to a wide acceptance of the doctrine that sex is inherited
in the ordinary Mendelian fashion. Using the Mendelian ter-
minology, one or the other of the two sexes is heterozygous for
the sex factor. Assuming that the male is heterozygous for the
sex factor, a female results from the union of any egg with a
female sperm; a male results from the union of any egg with a
male sperm. If the female is heterozygous for the sex factor a
female results from the union of a female egg with any sperm;
a male results from the union of a male egg with any sperm.
The question as to when sex is determined receives its answer
under the above hypothesis. Haecker’s classification of the time
when sex may be determined—progamy, syngamy, or epigamy—
resolves itself into one group, namely, syngamy.

So far, cytological evidence for the existence of a hetero- or
sex-chromosome in dioecious plants is lacking and the assumption
that one or the other of the sexes in dioecious plants produces two
kinds of germ cells is based only on indirect evidence in experi-
mental breeding. Correns and Bateson working almost simul-
taneously on Bryonia dioica and Bryonia alba, two species of the
genus Bryonia, the former of which is dioecious, the latter monoe-
cious and both of which cross readily, arrived at opposite con-
clusions. Correns concludes that it is the male of Bryonia dioica
that has two kinds of pollen, male and female, while Bateson
concludes that the female of Bryonia dioica bears two kinds of
eggs, male and female. The following are the results of the
crossings of Bryonia dioica with Bryonia alba which Correns and
Bateson secured:

70 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

B. alba selfed = all 8

B. dioica 9 X B. alba S = Fy, all females.

B. alba 2 X B. dioica # = Fi 50% males + 50% females.
B. dioica 9 X B. dioica 7 = 50% males + 50% females.

The hybrids produced are sterile.
Correns’s interpretation of his results is represented as follows:

B. dioica 9 has gametic constitution 9 9

B. dioica & 4 ® 2 & male dominant.
B. alba Q ae dé ia 8
B. alba J a 6 a 8

Bateson’s objection to the above schematic representation of
Correns is that it ignores entirely any degree of maleness in the
pollen of Bryonia alba in contrast to the dominance of maleness
in B. dioica male.

Bateson’s interpretation of his results is represented as follows:

B. dioica 9 has egg cells 2 and &
B. dioica & “ pollenall of
B. alba has egg cells @ and o and pollen all 9°

Strasburger, following Noll, has proposed the conception that
in dioecious plants the female has egg cells with only female
tendencies. The male gametes are of two strengths—strong and
weak. The assumption is made that the weaker of the two kinds
of male gametes in fertilization is weaker than the female gamete
and hence a female plant results; the fertilization of the egg of a
female plant by a strong male gamete results in a male plant.
Strasburger arrived at the above conclusions from an extended
study on dioecious forms. His conceptions were strengthened by
the behavior of his cultures of male and female plants of Mer-
curialis annua. ‘The interesting observations of Kruger’s in 1908
who reports that his so-called parthenogenetically produced seeds
on female plants of Mercurialis annua, upon germination produced
only female plants, were a confirmation of Strasburger’s earlier
observations on the same form. The further confirmation of
these results by Bitter in 1909, who reports that the seed of his
self-fertilized female plants of Mercurialis annua produced 723
female and 21 male plants left no room for doubt as to the behavior
of these female plants.

YAMPOLSKY: INHERITANCE OF SEX-RATIOS IN MERCURIALIS 71

Mercurialis annua, an annual weed, is described as occurring
in three forms—female, male, and hermaphrodite. Some female
plants, it has been established, produce a few male flowers and
are self-fertile. Some male plants occasionally produce a few
female flowers and they are self-fertile. The pollen from a male
plant upon a female produces seeds readily and in abundance.
The interesting observations recorded show that the seeds from
the selfed females produce exclusively or almost exclusively
female offspring; the seeds from selfed male plants produce ex-
clusively male plants (Strasburger); the seeds from the cross
pollinated plants produce approximately a fifty to fifty ratio of
males and females. Mercurialis then records the _ so-called
gametic constitution of its sexual cells directly in self fertilization.
The male cannot be regarded as heterozygous for sex in Correns’s
words since the offspring produced from its selfed seed are only
males, nor can the female be heterozygous for sex as Bateson
assumes since the offspring produced from selfed seed are only
females. Strasburger assumes that in the case of the approxi-
mately half and half production of males and females in the cross-
pollinated plants of Mercurialis annua it is the male plant that
determines the result. He interprets the phenomena of seed from
selfed female plants which give rise to females and seeds from
selfed male plants that give rise to male plants as evidence of
the well-known breeding fact that “like tends to beget like.”’

The present work was begun in February, 1914, and this com-
munication deals primarily with female cultures of Mercurialis
annua. A single vigorously growing female plant had produced
in January, 1914, 42 seeds. By April, 1914, the plant had pro-
duced 24 more seeds. The first lot of seeds was sown, 36 germi-
nated, and 36 plants were raised to maturity, all of which were
females. The second lot of seeds gave 14 plants, all of which
were females. Records of all these plants have been kept and
at the present time offspring up to the fifth generation have
been secured. I have made the following grouping of the plants
under my observation:

No. seeds
produced No. plants
I. Mothetplant<ac\.55 7 ha. Se 66 50 Fy
DL. Pi pdidesee es cae kro aly oe. fa 5. 60: 979 197 Fe
1 Vd PYRE ine) 2 ct A a 79+? 53 Fs
DVaU Bi) epee ted ea sees 367 118 Fy

Vie a eee aes ee Not counted Fs

Va MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

A total of 1491 seeds were sown, and they produced 418 plants,
all of which were females. The relatively low percentage of
germination of seed in Mercurialis annua is present in all cultures
of males, females, and hermaphrodites and cross-pollinated seed.
The seeds upon ripening are often lost because of the sudden burst-
ing of the seed capsule and the discharge of the seeds from them.
To prevent such loss the seeds were collected before they became
too ripe. Many of the seeds did not mature, these later proving
to be unviable. The fluctuation in the number of seeds produced
by the separate females presents a wide variation. Some plants
have produced as low as one seed, whereas one of the females has
produced 230 seeds. Twelve females produced noéseeds.

My first male plants were secured from the Brooklyn Botanic
Garden in November, 1914. Twelve plants in all were placed
among an equal number of females and permitted to cross freely.
Seeds set very profusely and several thousands were collected.

In May, 1915, the above seeds were sown in the experimental
plot of The New York Botanical Garden. Both male and female
plants in about equal numbers were produced. Over 700 male
plants were labelled and watched throughout the summer and
fall. The seeds from them are now being grown and the results
will be reported later. The males in general produce relatively
few seeds as compared with the females and more striking still
is the fact that less than 10 percent of all the males produced
any seed at all.

The results so far secured confirm Strasburger’s and bring out
very strongly the fact that there is a decided difference in the
seed production of such isolated individual plants. Strasburger
only indirectly called attention to the fact by giving the numbers
of seeds produced by each of his plants. The maximum number
produced by females under my observation was 230 seeds; the
maximum number produced by a male plant under my observation
Was 47 seeds.

In the January, 1916, ‘‘ Proceedings of the National Academy
of Sciences’? Goldschmidt reports in a preliminary paper upon
the sex-ratio in crosses between European and Japanese races
of Gypsy moths (Lymantria dispar). He gets various gradation
in his sexes unlike the well-known gynandromorphs. His indi-
viduals do not represent a mixture of the characters of the two

YAMPOLSKY: INHERITANCE OF SEX-RATIOS IN MERCURIALIS 73
sexes but a definite point between the extremes of femaleness and
maleness. He gets females which show feathered antennae of
medium size (feathered antennae are a male character), but which
are otherwise normal in appearance except that they produce
fewer eggs which are fertilized normally. He gets females which
have gone a step further towards maleness in the appearance
of male wing pigmentation and so on progressively until a female
becomes a male. With the increasing tendency towards maleness
there is a loss in the power of the female to lay eggs and examina-
tion reveals the transition of ovaries into testes.

In his male cultures he has secured stages in transition beginning
with a pure male up toa 75 percent female, while in his female
cultures he has secured what he calls ‘‘female males,” which can
be regarded as the limit of the male extreme. Goldschmidt
proposes the term “‘intersexes”’ for these individuals. Any one
of the above individuals, Goldschmidt claims, can be secured at
will by crossing certain strains.

The striking parallelism in the behavior of Goldschmidt’s
cultures of females and my cultures of females in Mercurialis
annua is significant. Potentially Goldschmidt’s female “inter-
sexes’’ may be regarded as functional. It is merely a matter of
environment that prevents their functioning. The females of
Mercurialis are self-fertile and produce seed. The female plant
that produces one seed on self-fertilization is more a female than
the one that produces 230 seeds upon self-fertilization. The female
cultures of Mercurialis annua may be regarded as exhibiting transi-
tion stages from femaleness towards maleness.

Correns’s work on gynodioecious plants is interesting in the above
connection. Plantago lanceolata exhibits various gradations in
forms between the hermaphrodite and female. Correns finds'
that the stronger the female tendency is present in a female plant
the weaker will be the influence of the hermaphrodite upon that
plant when they are crossed. The offspring resulting from his
cross will be females in over 90 percent of the plants. If, how-
ever, the female plant used tends in the direction of the herma-
phrodite, that is to say, it produces a few anthers, the hermaphro-
dite will influence the offspring so that there will be a dimunition
in the number of females and an increase in the number of herma-
phrodites.

74 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

Correns and Bateson’s results on Bryonia dioica and B. alba .

in the light of their interpretations would establish that one or
the other of the sexes of Bryonia dioica has two kinds of gametes.
The work on Mercurialis annua appears to negative the above as-
sumptions. Mercurialis does this by recording its own so-called
gametic constitution in the selfed males and selfed females.

The present work was begun in February, 1914, under the
direction of Professor R. A. Harper.

TRIASSIC PLANTS FROM SONORA, MEXICO, IN-
CLUDING A NEOCALAMITES NOT PREVIOUSLY
REPORTED FROM NORTH AMERICA

EpwWIN W. HUMPHREYS
The New York Botanical Garden

(WITH PLATE 5)

The collection on which this article is based is a very small one
in regard to the number of both specimens and species. Inas-
much, however, as our knowledge of the Triassic flora of North
America is comparatively limited, and as the collection contains
at least one well-defined species which apparently has not been
heretofore reported from North America and others whose range
it extends, it is of some interest. It was made a number of years
ago by Mr. Benjamin F. Hill in the Santa Clara Coal Field, Sonora,
Mexico, and was presented to The New York Botanical Garden
by Professor James F. Kemp.

Although many of the specimens are very fragmentary and the
identification of these is more or less unsatisfactory and incom-
plete, they are on the whole well preserved in a hard bluish-gray
shale and there seems to be every indication that more extensive
collecting in this region would add much to our knowledge of the
flora that flourished in North America during Triassic time.

At least two other collections of Triassic plants from this same
general region have been described: the one by Newberry,! from
Abiquiu, New Mexico, and Los Bronces and the Yaki River in
Sonora, Mexico; the other by Fontaine and Knowlton? from
Abiquiu, New Mexico. As indicated later, some of the plants of
the collection under discussion are apparently the same as those

1 Report of the exploring expedition from Santa Fé, New Mexico, to the junction
of the Grand and Green rivers of the Great Colorado of the West, in 1859, under the
command of Capt. J. N. Macomb: with a geological report by Prof. J. S. Newberry,

geologist of the expedition. Washington, 1876. (Fossil Plants, pp. 141-148. pl. 4-8.)
2 Proc. U. S. Nat. Mus. 13: 281-285. pl. 22-26. 1890.

76 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

described by the authors mentioned. The following are the
species:

PTERIDOPHYTA

Order FILICALES

PECOPTERIS BULLATA Bunbury, Quart. Jour. Geol. Soc. London,
3: 281. pl. 17. f.\Ffa, TOPE. 1847

Mertensides bullatus (Bunbury) Fontaine, Mon. U. S. Geol.
Sutv. 6:35. 21..25..f. 2-53 pb. 10. f ig ep ine PL. 16.) . ieee
Di TO. f.2.. Tos:

This species is by far the most numerous of the forms in the
collection. It is well preserved and there is no doubt as to its
being identical with that recorded by Newberry from Sonora,
Mexico. The specimens show both sterile and fertile fronds.
Fontaine considers Bunbury’s species as belonging to his genus
Mertensides but as the specimen in hand agrees perfectly with
that figured by Bunbury and by Newberry, while its agreement
with the genus Mertensides does not seem to be so close, the name
used by Bunbury is here retained.

ASTEROCARPUS FALCATUS (Emmons) Fontaine; Ward, Twentieth
Ann. Rep. U.S. Geol. Surveszaszep.. 22. f. 3. 1900
Pecopteris falcatus Emmons, Geol. Rep. Midland Counties,
IN 3227 5 AL Ao FA. 1856
Though well characterized only a single pinnule represents this
species.

ASTEROCARPUS VIRGINIENSIS Fontaine, Mon. U. S. Geol. Surv.
6:41. pb, 10. f:.2-55 PLO eis Pl. 21. f.. Fy epee
f.. 45 35 Ph. 23. J. eee J 1; 2. 88S
This species is well represented in the collection. Though the
finer nervation is not so well preserved as one might wish, the
outline and the coarser nervation leave little to be desired.

MACROTAENIOPTERIS sp.?
This is a very fragmentary specimen, and for this reason it is
not considered advisable to attempt to identify it specifically.
It is, however, closely related to Macrotaeniopteris magnifolia

HUMPHREYS: TRIASSIC PLANTS FROM SONORA, MEXICO 77

(Rogers) Schimper, which has been reported from Sonora, Mexico,
by Newberry.
Order EQUISETALES

NEOCALAMITES CARRERE! (Zeiller) Halle, Kgl. Svensk. Vet.-Akad.
Handl. 43: 6. 1908

Schizoneura Carreret Zeiller, Fl. Foss. des Gites de Charbon du
Vonkuners 71430 pl. 30..f.-1; 2; pli 37. f. 1; pl. 38: f. 1-8: 1903.

This specimen though somewhat smaller is apparently identical
with that figured by Zeiller on pl. 37. f. r. So far as the writer
is aware this species has not heretofore been reported from North
America.

SPERMATOPERY TA

Order CYCADALES

ZAMITES POWELLII Fontaine; Fontaine & Knowlton, Proc. U. S.
Nat. Mus. 13: 284. pls. 25, 26. 1890

While not as complete as might be desired, there is enough
of the plant preserved to show its identity with Fontaine’s species
from Abiquiu, New Mexico.

OTOZAMITES Macomsit Newberry (?), Rep. Macomb Expl. Exped.
Pate fe 132 Pl. Oss. 5, 50s L670

This identification can hardly be used as the basis of any

conclusions in regard to the geology or paleobotany of the horizon

in which the specimen was found as it is too fragmentary to per-

mit of much more than an exceedingly provisional identification.

ZAMITES (OTOZAMITES ?) sp.?

The remains of this plant are inso fragmentary a condition that
assignment to any particular species is precluded.

CYCADEOMYELON (?) sp.?

The fragment included in this genus is so poorly preserved
that it would not be worthy of notice were it not for the fact
that it represents a distinct plant differing from any of the others
in the collection.

78 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Order CONIFERALES

PALISSYA sp.?

This fragment of what appears to be the remains of a leafy
coniferous branch resembles very closely forms referred to the
above genus and to Walchia. As the greater resemblance is,
however, to the former, it is here included therein.

Explanation of plate 5

Neocalamites Carrerei (Zeiller) Halle; from Santa Clara Coal Field, Sonora, Mexico.
Natural size.

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 5

NEOCALAMITES CARREREI (ZEILLER) HALLE

A WHITE-CEDAR SWAMP AT MERRICK, LONG
ISLAND, AND ITS SIGNIFICANCE!

NORMAN TAYLOR

Brooklyn Botanic Garden
(WITH PLATES 6—I0)

The white cedar (Chamaecyparis thyoides) is sufficiently scarce
near New York City to make a grove of several hundred acres a
spot of peculiar interest. About twenty-five miles from the City,
at Merrick, on the south shore of Long Island, there is a cedar
swamp more than a mile long and varying in width from a few
yards to nearly half a mile. The same swamp has been noted by
Miss Mulford (12), Nichols (14), Bicknell (15), and Harper (13).

The general range of the species as given in the manuals is
(doubtfully indigenous in Nova Scotia) from southern Maine
south along the coast to western Mississippi. All of the stations
for it on Long Island are on the coastal plain except those near
Riverhead, where it is found between the Harbor Hill and Ronkon-
koma moraines. These stations near Riverhead are mostly
scattered trees, there being no grove of any considerable area.
Not only is this cedar swamp at Merrick the largest on Long
Island, but so far as the general distribution of the species is
concerned, it is the extreme northern outpost on the coastal plain
of any considerable grove, the other cedar swamps on the island
being much smaller. For this reason the occurrence of Chamaecy-
paris at Merrick and its behavior is of special interest. Chamaecy-
paris thyoides occurs in the area of which New York is the center,
either on the coastal plain, or in the glaciated region, not in the
intervening territory (7, 11, 19, 22, 24). In the glaciated area
it is scattered through southern and eastern Connecticut, northern
New Jersey and in Westchester, Putnam, and Orange counties on
the mainland of New York, and is nearly always found in glacial
pot-holes, or morainal depressions. On the coastal plain it is

1Brooklyn Botanic Garden Contributions No. 14.
79

8O MEMOIRS OF THE NEW YORK BOTANICAL GARDEN —

usually found along slow-moving streams in typically swampy
areas. But there are many such areas on the coastal plain of
Long Island where the species might be expected, notably near
Babylon (16) and along the Connecticut (Carman’s) River from
Yaphank to South Haven. But it has never been found at these
and several other likely localities. Just what the factors con-
trolling the appearance of the species on Long Island are, it is
impossible to say.

The swamp at Merrick stretches from about three quarters of a
mile north of the Long Island Railroad, along the banks of a
stream to the salt marshes, which are about three quarters of a
mile south of the railroad. The best present development of the
swamp is at the northern end, on the property of Harold Bunker,
Esq., who has carefully protected the existing grove. <A good-
sized pond, caused by the damming of the stream about a hundred
years ago, divides this northern part of the cedar swamp. All
of the region now occupied by the pond was once covered by white
cedar trees, submerged stumps of which may still be seen in the
clear water. PLATE 6 shows the present general aspect of the
region, and PLATES 7 and 8 the upper ends of the pond and
the growth of cedars beyond. These trees mark the northern
limit of the grove. To the southward the swamp has suffered
much from fire and from the pumping operations of the City, a
reservoir having been made just north of the railroad, thereby
clearing the trees from this area. To the south of the railroad
the cedar trees stretch uninterruptedly to the salt marshes near
which there is a conspicuous fringe of dying and dead trees.

One of the most characteristic plants of the undergrowth in
white-cedar swamps is Rhododendron maximum (19, 22), and,
in the south, Magnolia. Neither of these are found in the swamp
at Merrick, and indeed the character of the undergrowth there is
such that several interesting problems are suggested by a study
of the floristic content of the whole swamp.

The commonest tree, besides the Chamaecyparis, is Acer caro-
linianum, if this be nota mere formof A. rubrum. Morescattered,
and much less common are Nyssa sylvatica, Quercus rubra, and
strangely enough, Sassafras, which is very plentiful in the dry
reaches of the adjacent coastal plain scrub, but seems perfectly
at home also in the deep shade of this moist forest. See PLATE
9 for general aspect of the interior of the swamp.

TAYLOR: WHITE-CEDAR SWAMP AT MERRICK, LONG ISLAND 8I

But it is the character and composition of the undergrowth
that is of chief interest. With Rhododendron and Magnolia
lacking, the dominant undergrowth is as follows:

Woopy PLANTS

Clethra alnifolia Aronta arbutifolia
Gaylussacia frondosa Nemopanthus mucronata
Alnus rugosa Ilex laevigata

Azalea nudiflora Ilex glabra

Azalea viscosa Ilex verticullata

Benzoin aestivale Vaccinium atrococcum
Hamamelts virginiana Vaccinium atlanticum
Viburnum dentatum (rare) Rubus hispidus
Eubotrys racemosa Vitis aestivalis
Toxicodendron Vernix (rare) Toxicodendron radicans
Sambucus canadensis Smilax rotundifolia
Aronia atropurpurea Parthenocissus quinquefolia

HERBACEOUS PLANTS

Dryopterts simulata Viola pallens
Woodwardia areolata Viola papilionacea
Woodwardia virginica! Trientalis americana
Spathyema foetida Panicularia obtusa
Arisaema triphyllum Lilium canadense
Carex Collinsit? Vagnera racemosa
Carex Howet Triadenum virginicum
Untfolium canadense Mitchella repens

The list is doubtless not complete but it serves as a guide to
the most characteristic and commonest species in the swamp,
which seems to have reached its climax or ultimate development,
there being practically no open places in it, and being apparently
farthest removed from the open-water, initial stages of white-
cedar swamps described from near Woods Hole (9).

The odd feature of this aggregation of plants is that a compara-
tively cool habitat, many degrees cooler than the hot coastal
gravels of the adjacent region, is here conditioned by the stream,
and by three southern trees that are much nearer their northern

1 The three ferns reported by Mrs. Britton and Miss Mulford (12).

2 Carices kindly determined by Mr. K. K. Mackenzie.

82 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

than their southern limits. The shade and consequent coolness
are mostly caused by the dominant Chamaecyparis, and the
slightly less common Acer carolinianum and Nyssa, all of which
are here near their northern limits, two of them being known only
from Maine, the other from southern Massachusetts, southward.

An analysis of the woody undergrowth shows the same char-
acteristic. Seventy-six per cent of the shrubs and vines at the
Merrick swamp are of southern rather than northern affinities.
Similar figures for the cedar swamps in Connecticut (22) show
68 per cent of the woody plants as southern and in the pine-barrens
77 per cent (19). How accurately these figures represent the
dropping out of southern woody species as we come northward
no one can say, but at least they indicate the general tendency of
the white cedar to be associated with typically southern woody
plants and to lose some of these, but not many, as it occurs
northward. We have then a cool, almost coniferous-bog condi-
tion of the north, on a hot coastal plain, caused mostly by southern
trees and shrubs, all of which are much nearer their northern edges
of distribution than their southern.

This raises at once the question as to what is the character of
the herbaceous vegetation occurring in the swamp. An analysis
of the above list shows that 77 per cent of the herbaceous vege-
tation is northern rather than southern. Similar figures from
Connecticut show about 70 per cent of northern herbs. We have
in this a really remarkable condition, some of which may be due
to historical factors. Here, in a locally cool region, we find
an aggregation of northern herbs vastly in excess of the percentage
of such herbs in the surrounding region and their occurrence
conditioned by the shade provided by predominately southern
woody plants.

The mixture of these northern and southern elements in one
swamp, which is, as shown above, not peculiar in this respect,
is an excellent, if rather concentrated example of the distribution
of the Long Island flora generally. The great majority of species
on the coastal plain are southern, many of them reaching their
northern distribution outposts on the island. Along the morainal
ridge and north of it, however, the species are more northern in
character. More or less of a tension zone exists between these
two elements. But in this cedar swamp there is no evidence of a

TAYLOR: WHITE-CEDAR SWAMP AT MERRICK, LONG ISLAND 83

tension zone, for here, crowded in a small area, are two groups of
species, three quarters of the woody plants of which are southern
and three quarters of the herbaceous plants northern.

The conviction that these cool-atmosphere, typically northern
herbaceous species are found in the cedar swamp merely because
the environment is favorable and not as the result of some far
reaching, almost catastrophic agency, seems inevitable. That
the large percentage of herbs should be northern and that an
equally large percentage of woody plants should be southern,
does no violence either to the theory of Sinnott and Bailey as to
the origin of herbaceous angiosperms, or to the observed ratios
of growth-forms as worked out by Raunkiaer. The chief sig-
nificance would seem to lie in the fact that the occurrence of these
northern herbs at this point, and probably at other shaded swamps
on the island, is conditioned by a group of southern woody species,
which have failed to bring with them from the south the herbs
with which they are there associated. And just because these
southern woody plants have created a favorable habitat we find
in their shade a growth of northern herbs, which, needing such
conditions, are likely to occur there and nowhere else. This
looks like a commonplace way of accounting for the mingling of
two such diametrically opposed elements in the same swamp, but
Chamaecyparis swamps further south seem to indicate that the
southerly range of a number of northern herbs is conditioned by
the occurrence of these swamps. Upon this conception the
distribution of the tree is of less significance than is the fact that
its occurrence postulates conditions favorable for the growth of
herbs that would not be there if the Chamaecyparis was lacking.
And the white cedar does, to a peculiar degree, make unusual
conditions on the coastal plain, the dense cool shade being in
such marked contrast to the surrounding region.

THE WHITE CEDAR AND THE SALT MARSHES AT MERRICK

Near the lower end of the cedar swamp, the trees begin to
thin out, both as to frequency of occurrence and size, and im-
mediately facing the salt marsh there is a large area made up of
dying or wholly dead Chamaecyparis trees. See PLATE 10.
Facing these is the salt marsh, which is nearly two miles wide.
There is one good-sized tidal stream in it having near its upper

84 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

limit, which is near the dead cedar trees, a rise and fall of about
18 inches. Occasional special high tides flood the lower stretches
of the cedar swamp and it is this that kills off the cedar. For
this tree is not a salt tolerant, while Nyssa and Quercus stellata,
inveterate inhabitants of the edges of most Long Island salt
marshes, flourish among the dead evergreens.

It has recently been suggested by a geologist (23) that if along
the edges of salt marshes there were to be found a well-marked
zone of vegetation that seemed to be putting up a losing fight
against sea water, it would be excellent evidence that coastal sub-
sidence was well marked in the region. The reasoning seems to
be sound, especially for trees that are not good salt tolerants. It is
unlikely that such trees would become established if the amount
of salt water had in the past been unfavorable, but once having
reached maturity in a given situation, the question of the cause
of their death seems to force on one the necessity of accounting
for the obviously recent encroachment of the salt water. Such
seems to be the case at Merrick as PLATE 10 shows.

Local conditions here made it easy to study the probable de-
velopment of the whole salt marsh. Extending out into the
marsh, just west of the area below the cedar swamp, is a long
promontory of higher land that reaches for nearly a mile towards
the bay. This lobe of drier land maintains a flora much like that
of the upland region of the coastal plain, except that the red
cedar, Juniperus virginiana, is the dominant tree. With scattered
plants of Quercus stellata, Acer carolinianum in lower parts,
Myrica carolinensis, Rhus copallina, a Vaccinium or two, and
Rosa carolina, the bushes often tangled all together by Smuzlax
glauca, we pass by easy and rapid stages through thickets of
Baccharis and Iva to the open salt marsh which is quite bare of
woody vegetation. All these types may be found within twenty-
five feet of one another. The surface evidence of coastal sub-
sidence here is not convincing, for while this edge of the lobe of
higher land is much nearer the bay, no fringe of dead or dying
plants is to be found as in the case of the white cedar. The reason
too is obvious, as all the species above mentioned as inhabiting
the edges of the drier land, are good salt tolerants and not likely
to be affected by occasional inundations of sea water.

It is unnecessary to review here all the pros and cons of the

TAYLOR: WHITE-CEDAR SWAMP AT MERRICK, LONG ISLAND 85

question of coastal subsidence, ancient and modern. That there
has been such, both ancient and recent, seems quite clear not
only on the evidence of older writers (1, 2, 3, 4, 18, 20, 21) but
on evidence collected at pits dug in the marsh at Merrick in
1915. If the whole region has been sinking we should expect to
find vegetable remains indicating a different type of flora on the
area now overlaid by the marsh. And if these vegetable remains
are not fossilized the presumption is that they are all postglacial
and not to be confused with glacial or interglacial material (10).
Such vegetable remains would seem like mute evidence of sub-
sidence. With these points in mind, four pits were dug in the
marsh situated as follows:

I. Nearly two miles from the white-cedar trees, the surface
vegetation on the marsh where the pit was dug being made up of,
Spartina cynosuroides

Spartina patens

Distichlis spicata

Salicornia europaea
which should be evidence enough that it is near the outpost
of salt-marsh vegetation. It is within a few hundred yards
of the bay. The first two feet of digging was through solid turf
of Spartina cynosuroides, and its roots. At three feet and five
feet partly decomposed remains of the same grass, all enveloped
in foul-smelling black ooze, was found. It was not possible to
get down lower than this, the digger being unable to get footing
as the water rose. All of the remains here point to the region
having been salt marsh far back in the history of the region.
This is what we should expect, for if the region has been sinking,
presumably this seaward edge would show merely a repetition of
previously existing salt-marsh flora, which is exactly what our
evidence points to. Just how far back it has been in this con-
dition it is impossible to say, as guesses have varied from a few
inches to a foot or more a century as normal subsidence (1, 5, 18).

II. About 100 yards seaward of the extremity of the lobe of

higher land. Surface vegetation at the point w here the pit was
dug consisted mostly of the following:

Limonium carolinianum Salicornia europaea
Solidago sempervirens Plantago major halophila
Tissa marina Plantago maritima

Juncus Gerardi

86 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

For the first 18 inches the turf formed an exclusive and very
tough mat, just beneath which were found a large quantity of
clam shells, emphatically not a kitchen midden. These have
been identified as Venus mercenaria which is ‘‘common in shallow
water on muddy bottoms in the bays and estuaries about Long
Island.’"! Below the clam shells apparently pure beach sand and
gravel were found with very few traces of vegetable remains.
Here the inference that we have to do merely with a recently
sunken beach whose clam strewn shore has been covered by
‘“‘salt hay’’ seems clear enough.

III. Within one half mile of the edge of the cedar swamp and
about 100 feet from the tidal stream, which seems from the
general configuration of the land to have always been the natural
drainage of the stream now flowing through the cedar swamp.
The surface of the ground where the pit was dug was covered prin-
cipally by the following:

Spartina patens Atriplex hastata
Distichlis spicata Agalinis maritima
Plantago maritima Limonium carolinianum
Sabbatia stellaris Solidago sempervirens

For the first 18 inches, as in the other pits, the turf was nearly
exclusive, but below we find an entirely new condition indicated.
Large quantities of twigs, sticks, wood, bark, leaves, half a hickory
nut, and other remains indicating vegetation decidedly not of
the salt-marsh type were abundant, mixed with fine clean sand
and gravel. There is an almost startling change between the
salt marsh surface and this evidently upland vegetation, now
buried. None of the remains could be definitely identified as
those of Chamaecyparts.

IV. Surface covering the same as at the third pit, except for the
addition of Sanguisorba canadensis and a few other swamp plants.
This station is just outside the zone of dead cedar trees (see
PLATE 10) and the character of the remains practically the same as
in III, except that definitely identifiable Chamaecyparis remains
are fairly common.

What can all this point to but the gradual dying out of the cedar
and its replacement by salt marsh? The phenomenon has been
mentioned so many times before that there seems hardly any

1 Kindly identified for me by Mr. G. P. Engelhardt of the Brooklyn Museum.

TAYLOR: WHITE-CEDAR SWAMP AT MERRICK, LONG ISLAND 87

warrant for bringing it up again (17). In the case of the seaward
end of the marsh we find merely a repetition of what has probably
been always salt marsh. Nearer the present cedar swamp we
find evidences of buried cedars, now more than two miles from
the bay, and covered by typical salt-marsh flora. In the inter-
vening region off the line of the probable drainage of the old
fresh-water stream, now tidal, we find remains of a vegetation
almost exactly like that now found on the lobe of drier land that
extends out into the marsh. Here, again, this is now covered
exclusively by typical salt-marsh- flora.

The evidence of costal subsidence thus seems entirely conclusive.
While no new facts in connection with that controversy have been
stated, with the possible exception of the record of the dead zone
of cedar trees, it is surely of significance to find such evidence so
far back from any barrier beach or other possible regulator of
exceptional tides, which has been suggested as a possible alterna-
tive to recent subsidence.

The cedar swamp at Merrick, then, is of interest (a@) because
it is probably the most northerly grove on the coastal plain of
anything like that size; (b) the character of its undergrowth;
(c) the evidence of coastal subsidence suggested near the transi-
tion between the grove and open salt marsh, by the large number
of dead and dying trees.

BIBLIOGRAPHY

1. Cook, G. H. On a subsidence of the land on the seacoast of New
Jersey and Long Island. Am. Jour. Sci. II. 24: 341-355. 1857.
Geology of the county of Cape May (N. J.), 62 and 39.

iS)

1857.

3. Lewis, E., Jr. Evidences of coast depression along the shores of
Long Island. Am. Nat. 2: 334-336. 1868.

Ups and downs of the Long Island coast. Pop. Sci.
Monthly 10: 434-446. 1877.

5. Shaler, N. S. Sea-coast swamps of the eastern United States.
Ann. Rep. U.S. Geol. Surv. 6: 359-398. 1884.

6. Hollick, A. Plant distribution as a factor in the interpretation of
geological phenomena, with special reference to Long Island and
vicinity. Trans. N. Y. Acad. Sci. 12: 189-202. 1893.

7. Gifford, J. Distribution of the white cedar in New Jersey. Gard.
& Forest 9: 63. 1896.

88 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

8. Knowlton, F. H. Catalog of Cretaceous and Tertiary plants of
North America. Bull. U.S. Geol. Surv. 152:——. 1898.

9. Shaw, C. H. The development of vegetation in the morainal de-
pressions of the vicinity of Woods Hole. Bot. Gaz. 33: 437. 1902.

10. Berry, E. W. Paleobotanical notes. Bot. Gaz. 39: 232. 1905.

11. Harper, R. M. The coastal plain plants of New England, their
history and distribution. Rhodora 7: 69-80. 1905; 8: 27-30. 1906.

12. (Anon.) Field meetings of the Torrey Club. (May 30, 1906.)
Torreya 6: 130. 1906.

13. Harper, R. M. A Long Island cedar swamp. Torreya 7: 198-200.
1907.

14. Nichols, J. T. New station for Chamaecyparis on Long Island,
New York. Rhodorag: 74. 1907.

15. Bicknell, E. P. The white cedar in western Long Island. Torreya
8:27, 28. - 1908.

16. Harper, R.M. The pine-barrens of Babylon and Islip, Long Island.
Torreya 8: 1-9. 1908.

17. Bartlett, H.H. The submarine Chamaecyparis bog at Woods Hole,
Massachusetts. Rhodora 11: 221-235. 1909.

18. Davis, C. A. & Bastin, E.S. Peat deposits of Maine. Bull. U.S.
Geol. Surv. 376: 19, 20. 1909.

19. Stone, W. Plants of southern New Jersey with special reference
to the flora of the pine-barrens. Ann. Rep. N. J. State Mus.
FOTO?°70,; 1512) LOT2:

20. Clarke, J. M. [Review of D. W. Johnson’s] Fixité de la cdéte
atlantique de l’Amérique du Nord. Science II. 38: 26. 1913.

21. Johnson, D. W. Botanical phenomena and the problem of recent
coastal subsidence. Bot. Gaz. 56: 449-468. 1913.

22. Nichols, G. E. Vegetation of Connecticut. Torreya 13: 89-112.
1913. Bull. Torrey Club 42: 169-217. 1915.

23. Fuller, M. L. Geology of Long Island, New York. Prof. Paper
U. S. Geol.-Surv. 82: 212-216. I914.

24. Taylor, N. Flora of the vicinity of New York: A contribution to
plant geography. Mem. N. Y. Bot. Gard. 5: 4, 11, 74 and pl. 6.

IQI5.
Explanation of plates 6-10

PLATES 6-8

Bunker’s Pond, Merrick, Long Island, New York, showing upper end of white-cedar
swamp.
PLATE 9

Interior of white-cedar swamp below Bunker’s Pond, Merrick, Long Island, New York.
PLATE 10

Contact of white-cedar swamp and salt marsh, Merrick, Long Island, New York.

dWVYMS UVGaAI-ALIHM HO GNA AAddN ONIMOHS ‘GNWIST DNO7T ‘MOINNAPY ‘GNOd S YaNNng

onamp tpn acca, Sree ee Ss x“ x “te 4 See een

‘. hs 6, RS pate as kewnteneiae a a a Teas

Q ALV1d ‘TA AWNIOA NAGUV‘) “LOG “A 'N ‘WNATY

=
ere |

Se ee wo i ee

Tie eee

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE

BUNKER’S POND, MERRICK, LONG ISLAND, SHOWING UPPER END OF WHITE-CEDAR SWAMP

PLATE

alr,

VOLUMI

GARDEN

Bot.

EM.

BUNKER’SyPOND, MERRICK, LONG ISLAND, SHOWING UPPE

DAR SWAMP

C1;

ND OF WHITE

“

VI,

VOLUME

GARDEN

DIVien NG Ss Oe

POND, MERRICK, LONG ISLAND

R'S

®)

BELOW BUN

WHITE-CEDAR

ZRIOR OF

INTE

GNVIS] DNOYT ‘MOIYA] ‘HSUYVN LivSs GNV dNVMS UVGHO-ALIHM AO LOVINO )

Ol ALVId ‘JA AWAIOA NaGUVS “LOG “A 'N ‘WAIN

7 .
1 -* ' tbe .
> *
. °
>
* 1 1]
e f
xe ;
ie . ad . ’ ,
. :
© i "

_ < ‘ “
ys
ie, es .
- _ a ~*
4 .
— »
& : -
a
ints ; a *
~* +
» ie -ine :
' /
r 4 <
¢ bs » P :
% ¥
% . »
- a Bw iy i -

INHERITABLE VARIATIONS IN THE YELLOW
DAISY (RUDBECKIA HIRTA)!

ALBERT F. BLAKESLEE

Station for Experimental Evolution

Variations in the following characters have been found in the
wild yellow daisy: absence of rays and their presence in rather
definite numbers from 8 to 30 and to perfectly double forms;
width of rays; diameter of head from 1 to 5% inches; color of rays
from pale straw color to deep orange; relative intensity of color in
inner half of ray forming a lighter or darker ring; different in-
tensities of mahogany color at base of ray on upper side; mahogany
on under side of ray; constriction of ray at tip, at middle, or at
base—those constricted at tip, either rolled in or rolled out to
give the ‘‘cactus’’ type seen in dahlias—those constricted at
base without change in color or characterized by lighter color or
by presence of black pigment on constricted areas; transformation
of rays into tubes giving ‘‘quilled’’ type; the position of rays,
bending upward, horizontal, reflexed, straight or variously twisted;
the shape and size of disk; the color of disk from yellowish green
through several grades of purple to almost black; vegetative
characters such as height, branching, size and shape of leaf,
fasciations, etc.

Evidence from the distribution of the variants in nature and
from their reappearance in sowings from open-pollinated heads
shows that most, if not all, these variations are inherited. The
basal splash of mahogany on the ray seems to be inherited as a
simple Mendelian dominant, while another red blotching is in-
herited as a recessive. Other characters are being investigated.

1 Abstract. The paper was illustrated by living specimens.

aa [Ps D
_ 4
© ‘ : on
fy : i £ a oT a
} ’ : ara Ae
eT aioe Ml 2 tis” See a ®
aw't-3 4 . vw “2 i rye ys
>... VU EOP A AW SCRAP ESe
a y + j 7 ge ¥ ag : * ; } y -
/ \ SSP RUA for Ad oer
} : Dee. 5< ok, , = a es
r wae mre Pio Lee ae F 1 | J ae ad
7 ey 3 Pat al)
ta ie ' siteHie MU: Ls ieret 8 4 4 i svaae, fe
S sue - f 4 . 7 : ue
i ae : . ’
: ‘ ye avt, ~
ioe ae Pee eIWinaeelt a hrotl ig ody: Gt sent: i
7 : , % ry > 5 Pe ? “ ‘
oN Me i ary ade wt}? hen iy OOM TF beer 0 4 ay 4 val agi cp ay
1 ee j ni ek a 2) , ee: |
J oye ‘vag AD Gk, a Mwy i sreiici yee hyena iit a _
: et aw ane. eur ;
cee ( — \. - Vidi q Fe ead WY ' va, H ro “El? oe i fel Bey it ;
“a 4 7 - a ' ad 4 aa '
4-% le cs YiyRariy sve + tet ha: aT Oe CRTC Pe ee
A Me Mie Pheri hy ey 7 TORE? te atte - Dy Ae Va 7a
$1 : STM OR IEE MOE ye De is iit Sieur
a | pri Ss BAT" Beal ve ‘ a iv) ven
i s iS Lb 4 wir “ie “ye : eisai, oH Pie as
‘ iy te é ,!
“vorr’s sores &D cpt ct ‘ mitt #7. 4a.
ta ult te Tag pectin eet ed ‘ere ih Sota tae
ae -
7 j 4 ¢ ( itd / 4 Waet iyi. ter" Ady
. : cH he A i eek! 4 A
. ‘ a ria ‘ A» d Cr e479 yi at ee wa ‘9
¢ : as .*
1} . : i Arey 4 uc. a3 vi 9
F J '
r) ' > ' “GE FT; Z arta to) bibs
> , 5
ae ' ,
. ¥ %
let,
RSE }
wz} ,
a eer" }
' b ont
Je re a . # ; . }
s} Ky : r a
‘
| —
ae
“4 7
.
BPE ee Seeks
é gee Wee ital Cr el

ON THE NATURE OF TYPES IN PEDIASTRUM

R. A. HARPER

Columbia University

The Pediastrum group has been perhaps as much as any other
in the plant kingdom the subject of divergent judgments as to
the number and characterization of its species. Its sharp de-
limitation from all other genera by the form and life history of
the colony and the obvious subdivisions which are suggested by
the lobing of the cells were early recognized, but the wide range
of variation in cell proportions, number, and arrangement in the
colonies, has led to the most diverse opinions as to the number
of species which should be recognized. Nitardy’s (6) summary of
the literature brings out very adequately these divergent views
as to what should constitute specific characters in the group.

Pediastrum is also interesting as a type in which the beginnings
of cell differentiation in a coenobic colony are clearly shown. In
the common species, P. Boryanum, the cells of the outer series are
each provided with a pair of conspicuous spine-like lobes. In
some other species the difference between the cells is less marked.
We have thus before us incipient stages of differentiation in
structure and an approach to a typical metaphytic habit.

As Meyen (3) observed, the specific organization of the colonies
of Pediastrum, as shown in the arrangement of its cells, is most
mathematically definite in general plan but shows: an almost
infinite degree of fluctuating variation in its details. As noted
by Naegeli, (4 and 5), Al. Braun (1) and others, the most common
form of the 16-celled colony of P. Boryanum shows one cell in the
center with five cells around it and ten in the outer circle. The
cells are really as nearly as possible in groups of three, which
is the most compact arrangement they can assume. At all
points of contact, we find three walls converging to a point as in
a typical foam structure with one layer of vesicles. Less com-
monly, as Naegeli and Braun also observed, there is a central
group of 4, 5 or 6 cells with 12, I1 or 10 cells respectively in the

Q2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

outer series, still other arrangements are also found. Braun
notes more specifically the possible variations in the inner group,
which, however, need not concern us here.

In my study of the colonies of Pediastrum all the measurements
of angles, arcs, etc., were made on photomicrographs such as are
reproduced in the figures. The photographs were from four to
ten cm. in diameter in the material here discussed. The magni-
fications are given in connection with the figures. In some cases
the original print as taken was enlarged by rephotographing it in
order to make it easier to measure the angles. This was done in
the case of both FIGUREs Ia and 2a.

The difficulties in the way of measuring the angles in such
small figures are, of course, very great. A transparent xylonite
protractor with radi from the center marking the angles of 120°
was used and the angles were read by laying on a ruler. All
three angles about a point of intersection of the cell walls were
read with a single placing of the protractor so that the sum of
the angles about such a point was always made 360°, a result
which, of course, would not be achieved if the protractor was
placed anew for each of the angles to be measured. No claim
can be made for great accuracy in the measurements. The
breadth and frequently the vagueness in the outline of the cell
walls in the photographs precluded the possibility of getting a
high degree of consistency in the measurements even when re-
peated many times. There is no question, however, that much
more accurate results can be obtained by measuring photographs
than by attempting to measure the angles directly on the organism
under the microscope. And the data obtained are certainly con-
vincing on the general point that where, as is so regularly the
case in the 16-celled colonies, the cells in their contacts form groups
of three, the angles of intersection of their walls fluctuate about
120° with deviations which correlate directly with the number of
cells in the colony, their inherited form, etc. The measurement
of the angle which each cell of the colony subtends could be made
with greater accuracy.

The colonies of Pediastrum tend to conform to the principle of
least surfaces both in the shape of their cells and in the form of
the group as a whole. Each cell tends to become as nearly
spherical as is consistent with its inherited form tendencies and

HARPER: NATURE OF TYPES IN PEDIASTRUM 93

its adhesion to the adjacent cells. The colony as a whole also
tends to become as nearly circular in outline as is possible with
the number of cells of which it is composed and their individually
inherited forms. That is, the cells are arranged as compactly
as possible under the given conditions.

That the organization of the colony is in conformity with the
principle of least surfaces is obvious from inspection and can be
illustrated statistically as will be shown more fully elsewhere.
The common arrangement of the cells in each case approximates
that of the most nearly corresponding one of the series of groups
of circles consisting of 7, 19, 37, 61, etc., which may be called the
least surface groups. In such groups the circles are in concentric
series and as compactly placed as possible. The diameters of
such groups form the series 3, 5, 7, 9, II, etc., and each successively
larger group differs from the last by one additional peripheral
series, the numbers of circles in the successive peripheral series
being 6, 12, 18, 24, etc.

The 16-celled colony, for example, is nearest to the group of
nineteen circles which consists of series of six and twelve concen-
trically placed about a central circle, while the colony of Pedi-
astrum consists of five and ten cells concentrically placed about a
central cell.

In view of the deeply lobed and highly irregular contours of
the cells in most species of Pediastrum, it seems perhaps quite
contrary to fact to speak of them as illustrating the principle of
least surfaces. Still, there can be no doubt that this adult form
of the cells, their anomogeneity, as Rhumbler (7) would call it,
does not prevent their grouping and the angles of intersection of
their walls when in contact from showing a marked tendency to
approximate a least surface configuration.

The lobed form produces in many species intercellular spaces
bounded by curves re-entering the cell bodies and is a very char-
acteristic structural feature of the cells, but it is not in conflict
with the general tendency of the colony to assume a rounded or
slightly oval form. I have already noted elsewhere (2) that
there can be no question that this lobed form is inherited by the
cells as individuals since it is assumed by cells which are practically
free from tissue continuity and the ordinary environmental ad-
hesions to which they are subjected in the colonies.

g4 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

It is to be remembered also that, as was observed by the early
students of the group, each cell starts its development as a rounded
or slightly ovoid ciliated swarmspore and that the organization
of the colony is achieved by the cells while they have this form.
So far as their surface tension relations are concerned they behave
as mere viscid droplets of jelly-like material, both in the form
which they assume and the form relations into which they enter
with each other. The colony as it first appears in the vesicle
from the mother cell is a plate of rounded or ovoid bodies. The
more or less lobed form of the cells is wholly a result of their
growth; though it appears immediately on the cessation of the
swarming movement or even before movement has entirely ceased,
so that very young colonies are quite exact miniatures of the
mature ones.

The swarmspores are practically globular or oval plastic bodies
and the problem of their combination to form a flat plate in which
they shall have the characteristic arrangement found in the adult
colony is essentially that of combining sixteen such units into a

Fic. ta. Pediastrum Boryanum, sixteen-celled colony, X about 600. The origina]
enlarged about one half in reproduction.

b. Diagram showing the cell relations in such a colony. Dimensions obtained by
averaging the corresponding sides and angles right and left of the axis m—n, except in
case of the angles marked by an asterisk in the table, page 98. The dimensions of
the cells in the diagram were measured on a photographic enlargement about twice the
diameter of figure a. The diagram has beenreduced about one fourth in reproduction.

HARPER: NATURE OF TYPES IN .PEDIASTRUM 95

figure as nearly as possible like the more stable least surface
configuration which can be formed with nineteen such units.
The adhesion between the walls of the different cells acts in the
case of the whole colony quite as the molecular forces are sup-
posed to operate in producing surface tension.

We may take the 16-celled colony of P. Boryanum, which is
commonly figured in textbooks, to illustrate the principles of
organization common to the whole group. For convenience we
may number the series of cells in the colony from the center
outward. The central region of the colony may, as noted, show a
central group of three or four cells or a single cell. We may
number this central group or single cell 1, the next outer series 2,
etc. We may also number the cells beginning with the central
one, as shown in FIGURE 1). As there are in this case twice as
many cells in the outer series as in the next inner series (5), and
the cells are equal in size, it follows that two of the outer cells
subtend in general the same arc as one cell of the inner series, that
is, 72°. Five of the outer third series stand radially outward
from the five cells of the second or inner series and five cells are
inserted with their middle points opposite the points of contact
between the cell walls of the second series.

In the common type of this species three cell walls meet at a
point throughout the whole colony. The alternate cells of the
outer series 3 are in contact with three or four cells respectively.
The cells of series 2 are each surrounded by six cells and the
central pentagonal cell by five cells.

Each cell of series 2 shows a slight re-entering angle on its
peripheral surface, indicating its tendency to become bilobed
like the peripheral cells. The central cell also shows such a re-
entering angle whose vertex is on a straight line through the
center of the colony and the surface of contact of cells 2 and 6.
It is obvious that the colony is bilaterally rather than radially
symmetrical with this line for its axis of symmetry.

If the cells were spherical in shape, and were nineteen instead
of sixteen in number, we should get the simple configuration of a
least surface group which represents the maximum of compactness
and stability. In a colony of sixteen instead of nineteen cells
which as in Pediastrum arises as a group of free-swimming swarm-
spores it is obvious that only the most favorable conditions with

96 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the least possible disturbance in the swarming period will permit
the achievement of anything like a symmetrical arrangement.
I have already (2) indicated the method by which the configuration
of the colonies is determined and shall describe elsewhere the
stages in their development with the evidence that the two-lobed
form of the cells is a character which is inherited by the cells and
comes to expression in some degree at least quite independently
of their position in the colony.

We are concerned now with the question as to the relation of
this more or less symmetrical organization of the colonies as we
find them to the physical principles illustrated in the formation
of least surface groups. It is obvious that the visible space rela-
tions of the cells to each other and to the organization of the whole
are simple and easily ascertainable. A drawing which represents
as far as possible a full expression of the tendencies which can be
discovered in the actual colonies is shown in FIGURE 10.

I have aimed in this diagram to eliminate all the irregularities
in position, size of cells, angles, etc., seen in the actual colony.
We can approximate such an ideal figure by taking the average of
the corresponding lines and angles right and left of the median axis
as they are found in a specimen selected for its regularity. The
dimensions of the lines and angles in this figure are obtained by
averaging those in the colony shown in FIGURE Id.

The fluctuations in any particular dimension vary rather
symmetrically about a mode common to the whole group and to
a considerable degree balance each other. Figures of aberrant
individuals and statistical data as to the fluctuating variability
in the group will be published elsewhere.

As was noted by Braun (1) the least surface grouping to which
the sixteen-celled colony tends to conform is that of nineteen
circles forming two series concentric about a central circle. If
these circles are flattened against each other we have the familiar
honeycomb configuration in which all boundaries meet in threes
and each included angle is 120°.

The conspicuous feature of the sixteen-celled group is that while
showing a concentric arrangement of the cells it is also bilaterally
symmetrical, its axis bisecting cells 1, 4, 7, and 12 and passing
through the surface of contact of cells 2 and 6. Except for the
slight reéntering angle on the side toward cell 4 the central cell is a
pentagon bounded by the bases of the five cells of series 2.

HARPER: NATURE OF TYPES IN PEDIASTRUM Q7

The three angles about the points of intersection of the contact
surfaces of each group of three cells tend to equal 120° each, but
with marked deviations owing to the number and inherited form
of the cells. For example, the interior angles of the central cell
at points g? and g® are smaller than the adjacent interior angles
of cells 3, 4, and 5. This is due to the tendency in the central
cell to assume a two-lobed form and for the same reason the
interior angles of cell 4 at these same points g? and g® are respec-
tively larger than the adjacent angles of cells 3 and 5. The exact
value of such differences cannot be determined without a knowl-
edge of the strength of the tendency in the cells toward the bi-
lobed form. I have made the values of the three angles 87.2°,
134° and 138° respectively by taking the average of the corre-
sponding pairs as the bilateral symmetry of the colony requires.

Correlated with this tendency of the cells to become bi-lobed the
interior angles of cells 2, 3, 4, 5, and 6 at the points d, d', d’, etc.,
are smaller than the adjacent angles of cells 7, 8, 9, 10, etc., the
differences here being about 20°.

In the diagram the lobed form of the outer surfaces of the
cells is merely sketched in free-hand. These cells represent
most nearly the inherited form tendencies of the individual since
from their peripheral position they have the largest proportion
of free surface and the fullest opportunity to bring to expression
those inherited tendencies which are not dependent upon contact
with or pressure from adjacent cells. The lobes of these peri-
pheral cells are longer but even in P. Boryanum the cells of series 2
and the central cell show clearly enough the tendency to the bi-
lobed form. The influence of internal environment in modifying
inherited form is especially well illustrated in such a case as this.

The dimensions of the cells and their interior angles in the photo-
graph and in the diagram are given in the following table. In each
case the sides and angles are taken in order beginning on the axis
of the colony. The most marked asymmetry in this colony is in
the region of cell 4, especially about the point e*? and I have given
arbitrary values to certain angles such as will conform to the re-
quirements of the general radial symmetry of the colony. The
four cases in which these arbitrary values have been assigned are
indicated by asterisks in the table. The area of cell 5 in optical
section as shown in the photograph is greater than that of cell 4,

98 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

but I have made cell 4 larger in the diagram. It is of course only
in very regular colonies that the averages of the single right and
left pairs of angles and sides will give a figure approximating the
typical surface tension configuration.

SIXTEEN-CELLED COLONY OF PEDIASTRUM BORYANUM

Interior angles and sides of cells
Central cell 1.

In colony. In diagram.
Angles:
1g = TLE?
igi! = 113.5° + 15g48 = 102.5° = 216° + 2= 108°
d'g%48 = 81° + a4g98 = 03.5° = 174.5 +2 = S72"
Sides
i= 9.5mm. + 7° = 10.5 mm. = 20 + 2 = IO mm.
@ = 9.25 mm. + 7 = 8.75 mm. = 18 + 2 = 9 mm.
Cells 2-6.
Angles:
kgi8 = 121° + kgt = 128° = 249° + 2 = 124.5°
igik! = 125° + kigit = 121° + ag*k*t = 129° +
Hgtkt = 129° = 504° + 4 = 126°
gk? = 136° + ek? = 132° = 268° + 2 = 134°
Bok? = 142° + 493k? = 134° = 276° + 2 = 138°

o'ek = 115° + oek = 108.5° + olelk! = 109.5° +
oe!k! = 106° + ovetkt = 119° + o8etk! = 109°
= 667° +6 = Litg

Re203 = 120° + Re20! = 95° = 215° + 2 = 107
k2e20! = 108° + ke%05 = 116° = 224° + 2 = 112°* 120°

odp = 109° + old'p! = 113° + o'd*p? = 102° +
old'p’ = 97° + o8d8p’ = 107° + o8d*p® = 109° +
o'd*p? = 100° + o8d*p§ = 112° = 849° + 8 106°
o'd'p! = 104° + o'd5p5 = 114° = 218 + 2 = 109* 100°
Sides:
k = 8mm. + 2! = 9 mm. + FR? = 6.5 mm. +
Rk? = 8.5 mm. + k* = 8mm. = 40.0 + 5 = 8 mm.

o = 7.5mm. + o! = 6mm. + o? = 6.5 mm. +
o} = 7mm. + of = 7mm. + 0 = 4mm. +

§6= 8mm.+ 0’ = 7 mm. + 0° = 7 mm. +

9 = 6mm. = 66 + 10 = 6.6 mm.

HARPER: NATURE OF TYPES IN PEDIASTRUM 99

Cells 7-16.
Angles:
o'e¢o = 136.5° + oleld? = 144.5° +
o'eto® = 132° = 413° +3 = 137°

o'e?ot = 132° + oe8o® = 149 = 281° + 2 = 140% 133°
ody = 125° + o'd'y! = 127° + o'd?y? = 127° +

o'd'r? = 134° + 08d’? = 125° + 8'PY =

224 h== 7008-6 — 126°

pdr = 126° + pld'r! = 120° + ped’r? = 131° +
pid'r? = 129° + prd’r8 = 128° + pid? =

129° = 763° +6= 127°

pdr’ = 122° + ped'r’ = 125° = 247° +2 = 1243

Cor = 138° + oe = 123°°= 261, = 2.= 130°
o'd'r! = 120° + o'd’r? = 126° = 246° + 2 = 123°*

mee

pid'r! = 136° + pid'r’ = 120° = 256 + 2 = 128°

Sides:
r= 9gmm.+7=9.5 mm. + 7? = 9mm. +
P= 8.5mm. + 7 = 8.5 mm.+ 7? = 9.5 mm. +
Y= 8.5mm. +77 = 7mm.+ 72 = 9mm. +
, Omnia — O75 1-10 8.7 mm.

Similarly, FIGURE 2b may be considered as representing the type
of cell configuration found most commonly in the eight-celled
colonies of P. Boryanum (FIG. 2a). The eight-celled, like the six-
teen-celled group, is in unstable equilibrium, owing to the number
of its cells (eight instead of seven). A group of seven spheres, six
around a central one, gives a much higher degree of compactness
and a more stable intercellular equilibrium than can be achieved
in a plate made of eight spheres. There is a considerable tendency
for one of the cells to slip out of the concentric system. In the
colony represented in FIGURE 2c, two of the cells are so displaced.

The grouping of the cells in such an eight-celled colony shows a
fine series of adjustments between mutual pressure, adhesion,
surface tension and the inherited form tendencies of the cells in a
system which is numerically disharmonic from the standpoint of
the principle of least surfaces.

In the more typical colonies, such as the one shown 1n FIGURE 2a,
the outer series of six cells forms in reality three pairs of spatially

100 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

similar figures, 6 and 3, 5 and 8, 4 and 7, but with their sides in
the same order. They can be conformably superimposed if they are
first rotated through 180° on the median axis of the colony, which
is a line de through the surfaces of contact between cells 6 and 7
and 3 and 4, and then again rotated through 180° on an axis at
right angles to this median axis of the colony.

Fic. 2a. Pediastrum Boryanum, eight-celled colony, X about 750. Original print
enlarged about one half in reproduction.

b. Diagram showing the symmetry relations in sucha colony. The dimensions of
the cells were measured on a photographic enlargement about twice the diameter of
figure a, and the average was taken of the corresponding sides and angles about the
axes de and fg. The diagram has been reduced about one fourth in reproduction.

c. Irregular eight-celled colony of the same species. Two cells not in concentric
order. XX about 750.

If the colony is split along its median axis and one half rotated
through 180° on a median line, cutting the axis at right angles,
it wili be bilaterally symmetrical, so far as its outer series of cells
is concerned, though its general radial symmetry will have been
much disturbed and the two inner cells are divided unequally.
These two central cells are in their outlines equal polygons and

HARPER: NATURE OF TYPES IN PEDIASTRUM IOI

with their corresponding sides in the same order. If the colony
is divided along the line fg, which is in the surface of contact of
the central cells, and one half is rotated through 180° on a median
line at right angles to the line fg, the two céntral cells form a
bilaterally symmetrical figure but two of the outer cells are divided
unequally.

The area of each of the central cells 1 and 2, as seen in the
figure, appears smaller than that of those in the peripheral series.
It is quite possible, however, that the central cells are propor-
tionally thicker than the peripheral cells. It is not easy to get
exact evidence by measurement as to the thickness of the colonies
at different levels as seen in edge view. The cell bodies appear,
however, to thin out toward the margin of the colony.

These two examples may suffice to illustrate the possibility of
recognizing what may perhaps be regarded as biological form
types of a group of related but fluctuatingly variable individuals.
The configurations shown in the diagrams (FIGs. 1) and 20) repre-
sent only the eight- and sixteen-celled colonies. The species has
8, 16, 32, 64, and even 128-celled colonies and for each different
number of cells the configuration presents new problems of equi-
librium and surface tension relations.

The configurations shown in these diagrams are, so far as my
observation goes, strictly ideal and while the form relations in-
volved are relatively simple as compared with the complexity
found in the higher plants it is certainly doubtful whether such
perfect regularity and equality of corresponding spatial elements
(lines and angles) could ever be a common occurrence in nature.

Such a figure does not, of course, represent the average indi-
vidual of a population, judged by degree of deviation from perfect
regularity. All these form elements, lines and angles, fluctuate
rather symmetrically about their modes and these modes are
approximately the line and angular dimensions of the perfectly
regular colony. It is the exceptional rather than the average
individual that approximates simultaneously in all elements this
standard of perfect symmetry. The average individual will nat-
urally fall below the specially favored one in its approach to an
ideal standard, determined in terms of the surface tension rela-
tions here involved.

While these figures, so far as form relations and cell arrange-
ment are concerned, may be considered as form types of sixteen-

102 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

and eight-celled colonies of P. Boryanum, such form relations
cannot, of course, be taken as giving any full expression of the
constitution of a true biological type for the species. Such a
type must represent many other characteristics of function and
life history. It is interesting, however, to note that the form of
the cells and their arrangement in more or less regular concentric
series which results in a plate-shaped colony have been regarded
by the critical students of the genus from the earliest times as
the most reliable diagnostic characteristics both for the genus
and the species, the form of the colonies and the arrangement
of the cells being the basis of the genus and the inherited form of
the cells the basis for the delimitation of species. The configura-
tion in such a diagram represents the form the most vigorous
individuals tend to assume when placed under the most favorable
environmental conditions and such a type represents the maximum
potentialities of the germ plasm of an individual or group under
such conditions. The determination of such types makes it
possible to distinguish the morphogenetic value of the specific
organization of an individual or group as contrasted with the
effects of environmental influence.

It may seem that in characterizing such a schematized con-
figuration as the type of a whole series of endlessly fluctuating
individuals there is a return to the vagaries of the ideal morphology
of the beginning of the last century and it cannot be questioned
that the evidence that the organization of the Pediastrum colonies
is determined by fundamental principles whose perfect and com-
plete expression is conceivable but is rarely if ever realized justifies
in some degree the recognition of predeterminable and ideal types
of structure. It is to be remembered, however, that the organiza-
tion here involved is based on the physical properties of the
substances concerned rather than any such abstractions as the
principle of perfecting metamorphoses or even of predetermined
harmonies.

Such types, of course, have little to do in many cases with the
so-called nomenclatorial and historical types recognized in rules
of nomenclature. It may, of course, be even a matter of accident
whether the first specimens of a species that are discovered will
happen to be biologically typical of the group to which they belong,
and it is conceivable that with rigid adherence to a doctrine of

HARPER: NATURE OF TYPES IN PEDIASTRUM 103

historical types the nomenclatorial grouping might remain perma-
nently at variance with a natural classification. It is to be re-
membered, however, that the careful student of to-day always
endeavors to arrange all available material in groups, based on
conceptions of phylogenetic types. So far as is possible he selects
as typical those specimens which illustrate most perfectly the
fundamental characters of the group for which they are to stand
in the type relation. The aim of any student of a group of genera
or species is to determine what are the natural types and his work
is likely to be lasting or ephemeral in direct proportion to his
success judged by this standard.

The possibility of discovering biological form types for the
bewilderingly complex individuals and groups found among the
higher plants may well seem too remote a possibility to have any
practical significance, even if such types can be conceived as
having any specific reality. The statement that every individual
is equally normal in the sense that it as much as any other is the
product of its environment plus its inherited constitutional
characteristics is even taken to mean that every individual is
equally typical of the “interbreeding group of blood relatives”’
to which it belongs.

The types set up by breeders of domesticated animals are arti-
ficially determined and may or may not coincide with what is natural
forthe race. Types determined by anthropometrical measurements
give very exact pictures of the dimensional characteristics of a pop-
ulation but are not, directly at least, referable to biological prin-
ciples of organization further than as they illustrate general tend-
encies to harmonies and adaptations in structure and functions.

What I have suggested as to the possibility of recognizing the
form type of a semi-coenobe like Pediastrum is much more ob-
viously true in the case of such simple filamentous coenobes as we
find in the free floating species of Spirogyra and other representa-
tives of the Conjugatae. Here the principle of organization of
the colony is of the simplest. We have merely a sort of cellular
metamerism, the exactly similar units being repeated ine tail
indeterminate series. The oblong cylindrical cell form is trans-
mitted directly in cell division and the axis of cell growth regularly
persists through sexual cell fusion, zygospore formation, and
germination. The arrangement of the cells is determined simply

104 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

by the repeated divisions of the cells at right angles to the axis of
the cylinder. The form type of such a coenobe is simply a cylinder
made up of segments of dimensions characteristic for the species
and inherited as qualities of the cells rather than of the colonies
as wholes. The disharmony between the numbers produced by
repeated cell bipartitions and those required to form stable surface
tension figures in one plant does not exist in the case of such
simple cylindrical types as are most of the Conjugatae.

I have described in the present paper only the organization
of the eight- and sixteen-celled colonies of P. Boryanum with
the object of suggesting the bearing of the data on the general
question of types. The real nature of this organization, both
cellular and intercellular, becomes clearer from a study of the
method of development and especially the variations in type of
both cells and colonies as found in the entire genus. Further
observations on these points, as already noted, will be published
elsewhere.

INDEX OF REFERENCES

1. Braun, A. Algarum unicellularium genera nova et minus cognita.
Lipsiae. 1855.

. Harper, R. A. Morphogenesis in Pediastrum. Science II. 37: 385.
7 Mr ToT.

3. Meyen, F. J. Beobachtungen iiber einige niedere Algenformen.
Nova Acta Acad. Caes. Leop.-Carol. 14: 771. 1828.

. Nageli, C. Gattungen einzelliger Algen. Ziirich. 1849.

Die neuern Algensysteme. Ziirich. 1847.

. Nitardy, E. Zur Synonomie von Pediastrum. Beih. Bot. Cen-
tralbl>.327: Tir. or.

. Rhumbler, L. Der Aggregatzustand und die physikalischen Be-
sonderheiten des lebenden Zellinhaltes. Zeits. Allg. Physiol.
I? 2790-388. “1902.

“NI

NOTES ON SOME MARINE ALGAE FROM’ THE
VICINITY OF BEAUFORT, NORTH CAROLINA!

MARSHALL AVERY HOWE and WILLIAM Dana Hoyt

The New York Botanical Garden Washington and Lee University

(WITH PLATES II-I5)

Most of the algae with which the present paper is concerned
were obtained by Mr. Lewis Radcliffe of the U. S. Bureau of
Fisheries through dredging operations on August II, 1914, in
“1314 to 14 fathoms”’ of water on a reef about 23 miles off shore
from Beaufort, North Carolina. Previous dredgings here under
the direction of the Bureau of Fisheries had shown this submerged
reef to be the northern limit, so far as known, of certain tropical
and subtropical algae, such as Udotea cyathiformis. The present col-
lection, though small, is of special interest inasmuch as it contains
two species that had previously been known from Europe only and
seven species that appear tous to be new. Some fragments of Dzc-
tyota dichotoma that were brought up by the dredge were particularly
remarkable for the number of small epiphytes and endophytes that
they bore.

Type specimens of the species described as new will be de-
posited in the U. S. National Herbarium; cotypes are in the
herbaria of The New York Botanical Garden and of W. D. Hoyt.
Other species of algae from the submerged reef and from the
Beaufort region in general will be described or enumerated in a
more extended paper soon to be published by the junior author.

Microchaete nana sp. nov.

Stratum inconspicuous, submicroscopic; filaments loosely gre-
garious, mostly 100-200 yp long, 5.5—-9.0 uw in diameter, curved near
base or near middle, often arcuate-flexuous, mostly decumbent
or ascending, occasionally prostrate or suberect, very slightly
attenuate towards apex; vagina very thin, delicate, hyaline,
scarcely visible; trichomata light olivaceous (?), 5.0-8.3 @ in

1This paper is published with the permission of the U. S. Commissioner of Fish and

Fisheries. :
105

106 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN —

diameter, slightly constricted at the septa towards apex, scarcely
so below; cells 1-3 (mostly I.5-2) times as broad as long, the
apical broadly dome-shaped or subhemispheric; heterocysts sub-
spheric or ovoid, basilar, rarely double, 5.0—6.6 uw in diameter, or
sometimes 8.34 long; spores unknown. [PLATE 12, FIGURES
I2-17.|

On Dictyota dichotoma, dredged ‘‘in 1314-14 fathoms,” Lewzs
Radcliffe, August II, 1914; accompanied by Streblonema soli-
tarium, Elachistea stellulata, Phaeostroma pusillum, Acrochaetium
affine, etc.

It was at first suspected that this plant might prove to be
identifiable with Microchaete purpurea J. Schmidt,! described as
an epiphyte on species of Fucus dredged near the Danish island
of Laess in the Kattegat, but a comparison with type material
of this species kindly furnished by Dr. F. Bgrgesen of Copenhagen
showed important differences. The trichomata of Mzcrochaete
nana are shorter than those of M. purpurea and are 5.0-8.3 pw in
diameter vs. 3-5y in M. purpurea; the filaments are loosely
gregarious and are mostly decumbent or ascending, while those
of M. purpurea form densely congested, suberect, wick-like clusters,
which in turn form on the surface of its host subdendroid or fucoid
figures, slightly suggestive of certain forms of frost-crystals on a
window-pane; the vaginae of the filaments of M. nana are thinner,
more delicate and less perceptible, though our material of M. nana
is formalin-preserved, while that of M. purpurea is dried, which
may account for a certain amount of the difference in this respect;
the color of the trichomata of M. nana is, perhaps, not well pre-
served, but it would seem to be a light olivaceous rather than the
red-purple of M. purpurea. Possibly Microchaete vitiensis Aske-
nasy, described from islands in the Pacific Ocean, is a nearer rela-
tive. From description alone, M. vitiensis would appear to have
erect and longer filaments (‘‘filis millimetrum vix attingentibus’’)
with thicker sheaths, which finally become ocreate.

Derbesia turbinata sp. nov.

Olive-green and nitent when dry, more or less repent, apparently
forming straggling mats 8-9 cm. broad (or high?), the basal parts
sometimes here and there resolved into cysts; filaments 15-95 pu
(mostly 38-53 “) in diameter, sparingly branched, the branching

1 Bot. Tidsskr. 22: 379, 412. 1899.

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. 107

subdichotomous or more often lateral, the lateral branches usually
without a basal septum, the others with or without one or two
septa above the dichotomy; chloroplasts at first orbicular, elliptic,
or ovate, 5-7 uw in diameter, later irregularly confluent and fusi-
form; sporangia turbinate, broadly obconic-obovoid, broadly
pyriform, or pestle-shaped, 112-182 yu long (excl. stalk), 104-156 u
broad, mostly about as broad as long, the apex subtruncate, the
outline commonly somewhat obdeltoid; pedicel mostly 14-32 u
(rarely 70 uw) long, 15-21 w broad, the pedicel cell usually about
18-21 w high and broad, or sometimes broader than high (10 pu
X 21 uw); spores immature. [PLATE II, FIGURES I0~-16.|

Dredged in 134-14 fathoms of water on reef about 23 miles off
shore from Beaufort, North Carolina, Lewis Radcliffe, August 11,
1914, in company with Cladophora sp.

In most of our material of Derbesia turbinata the chloroplasts
are more or less decolorate and disorganized and they show
numerous and conspicuous brownish violet pyrenoids. It is
probable that in the younger stages the plant may be of a bright
green rather than an olive-green color. Many of the sporangia
show no pedicel cell, but such sporangia as a rule are smaller and
evidently younger than those that are subtended by a stalk cell
and we are inclined to the opinion that this cell is a regular and
normal part of the stalk of the mature sporangium.

Derbesia turbinata seems to be distinguishable from the previ-
ously described species of the genus by its turbinate or very
broadly pyriform sporangia, the maximum width of which is
commonly about the same as their length, though sometimes a
little less and sometimes even greater. The pedicel is usually
very short, mostly 144—% as long as the sporangium, though, in
occasionally occurring pestle-like structures, the length of the
pedicel may approach that of the sporangium itself. Among the
hitherto described species, Derbesia turbinata is perhaps _ best
compared with D. repens Crouan, known to us only from descrip-
tions and the Crouans’ published figures. But D. repens is repre-
sented as having an obovoid or pyriform sporangium which is
twice as long as broad and the enlarged detailed figure of a prac-
tically mature sporangium shows no pedicel cell. D. repens is
apparently a smaller plant and an epiphyte.

Derbesia vaucheriaeformis (Harv.) J. Ag. was described from
Key West, Florida, from sterile material, but the sporangia borne

108 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

by southern New England plants that have been taken to be
identical with it are very different in form and size from those of
this Beaufort plant. Sterile specimens of D. vaucheriaeformis
collected by Harvey at Key West differ from D. turbinata in their
yellowish green color, less nitent facies, manifestly erect and
densely tufted habit, consistently dichotomous branching, and
smaller more polygonal chloroplasts.

STREBLONEMA SOLITARIUM (Sauv.) De-Toni, Syll. Alg. 3: 576.
1895.
Ectocarpus solitarius Sauv. Jour. de Bot. 6: 97, 126. pl. 3. f. 24-27.

1892.

On Dictyota dichotoma, dredged ‘‘in 134%-14 fathoms,” Lewzs
Radcliffe, August 11, 1914; accompanied by Elachistea stellulata,
Phaeostroma pusillum, Acrochaetium affine, etc. This species was
originally described as an endo-epiphyte of Dictyota dichotoma,
Dictyopteris |Neurocarpus| polypodioides, and Taonia Atomaria
from near Le Croisic on the western coast of France. In the
Dictyota, in France, it is commonly associated with Elachistea
stellulata, as is also the case in North Carolina. Both the Stredlo-
nema and the Elachistea have inconspicuous endophytic vegetative
filaments that make their way extensively in or near the cell
walls of their host. The cortex of the host (in this formalin-
preserved material from North Carolina) is so transparent that
by focusing into and through it with the compound microscope
one may follow the course of the interior filaments in a tolerably
satisfactory manner. These filaments, in the case of the Streblo-
nema, are found chiefly in the plane of juncture of cortex and
medulla, but they often penetrate the medulla and sometimes
reach the opposite cortex. They commonly follow the vertical
and longitudinal walls so closely that they are not readily obvious
on a casual examination. ‘The filaments may seem to anastomose
occasionally, but this is perhaps an optical illusion due to the
close crossing of filaments in slightly different planes. The
exterior part of the plant in its simplest conditions consists simply
of a single sessile plurilocular sporangium, or the sporangium
may be terminal on a simple few-celled exterior filament, or, in
better-developed conditions, the exterior filament, remaining
simple or subsimple, may attain a length of 750» and may bear

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. 109

one, two, or three short-stalked lateral sporangia. The exterior
filaments are I10.5-15.5 u in diameter and their cells are mostly
2-4 times as long as broad, though often much shorter at the
base of a terminal hair. The interior filaments have about the
same diameter as the exterior. The plurilocular sporangia are
40 — 78u X 14-36 yu. Since its discovery in France, Streblonema
solitarium has been reported from southern England and Ireland,!
but, so far as we know, has not hitherto been recognized as Ameri-
can. It is, however, to be expected wherever its host occurs.

Phaeostroma pusillum sp. nov.

Thallus irregular in outline or suborbicular, 0.3-0.8 mm. in
diameter, the component closely repent filaments and_ their
numerous curved or sinuous branches forming a moderately
compact, more or less pseudoparenchymatous unistratose mem-
brane, its margins commonly irregularly lobed or showing discrete
filaments, such filaments with frequent subdivaricate, often
recurved or incurved, occasionally pseudo-anastomosing branches;
vegetative cells subcylindric or more often curved or of irregular
diameter, mostly 10-I16y X 5-I0u, usually 1.5-2.0 times as
long as broad; chromatophores suborbicular, irregularly discoid,
or somewhat baculiform, commonly more or less fused, numerous
and crowded, occasionally substellate-conglobate, or less numerous
and somewhat reticulately disposed; hairs occasional, 8-10 w in
diameter, showing at the base 4-6 short cells (5-10 uw long); pluri-
locular and unilocular sporangia on separate individuals; unilocular
sporangia (I) scattered or aggregated, obovoid or subglobose,
8-16 w in diameter, sessile, or, (2) by subdivision and proliferation
of the fundamental cell and by coalescence, forming elevated
submoriform sori 16-48 yw in diameter, the ultimate sporangia then
smaller, mostly 5-8 in diameter, and often more angular;
microspores about I.5 uw in diameter; plurilocular sporangia scat-
tered and solitary or loosely gregarious, ovoid, ellipsoid, sub-
spheric, or subconic, sessile, suberect, 22-27 uw X 15-18 uw, about
7-9 loculi measuring the length of the sporangium and 4 or 5 its
maximum width. [PLATE II, FIGURES I-9.|

On Dictyota dichotoma and stolons of Campanularian hydroids
thereto attached, dredged in 1314-14 fathoms of water on reef
about 23 miles off shore from Beaufort, North Carolina, August
II, 1914, by Lewis Radcliffe. One of us (W. D. Hoyt) has ob-
served it also on Spyridia sp., collected at the same time and
place.

1 Batters, Cat. Brit. Mar. Alg. 30. 1902.

‘

I1o MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The Phaeostroma grows associated with Elachistea stellulata,
Streblonema solitarium, Acrochaetium affine, etc. It seems to
prefer to border the closely repent stolons of the hydroid and it
sometimes covers the stolons themselves. Most of the plants
bear the unilocular sporangia; those with plurilocular sporangia
are rare. Some of the plants with unilocular sporangia seem to
show all gradations between the isolated scattered sessile sporangia
(Fic. 6) and those that are aggregated on an elevated submori-
form sorus (Fic. 9), and we believe that this variation in the mode
of occurrence of the sporangia has no particular morphological or
physiological significance. The elevated sori observed have been
few in number and we have not ventured to sacrifice them in an
attempt to make a vertical section through them, but we infer
that the sterile pseudoparenchyma forming the base of the sorus
is more than one cell thick. Elsewhere, the thallus is manifestly
unistratose.

Of the four species that have been hitherto proposed for the
genus Phaeostroma the present plant seems most closely allied
to the type of the genus, P. pustulosum Kuckuck, which occurs
on the leaves of Zostera and on various algae in northern Europe
and Greenland. From this, however, as figured and described
by Kuckuck,! P. pusillum appears to differ amply in the smaller
thallus, which remains unistratose in sterile parts, in the series
of very short cells at the bases of the hairs, in the more regular,
more ovoid, more ectocarpoid, less tuberiform, less aggregated
plurilocular sporangia, and in the smaller (5-16 4 vs. 25-40 »)
unilocular sporangia, which sometimes occur in elevated sub-
moriform sori. So far as we are aware, the genus Phaeostroma
has not previously been reported from the American continent.

ELACHISTEA STELLULATA (Harv.) Griff.; Aresch. Linnaea 17: 261.
bl..0. f. 4. 1843: Harv, Phyc. Brigg 201. “T8465,
Sauv. Jour. de Bot. 6: 6. pl. 7.7. 2,2. 1892

Conferva stellulata Harv. Man. Brit. Alg. 132. 1841.
Phycophila stellulata Kutz. Sp. Alg. 541. 1849.
Myriactis stellulata Batters, Jour. Bot. 30: 173, 174. 1892.
On and in Dictyota dichotoma, “in 134-14 fathoms” of water,
Lewis Radcliffe, August 11, 1914; associated with Streblonema
1 Bot. Zeit. 53: 182-187. pl. 7. 1895.

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. III

solitarium, Acrochaetium affine, Phaeostroma pusillum, Microchaete
nana, etc.

The exterior parts of this interesting little endo-epiphyte form
subhemispheric or oblong cushions 125-300 uw in diameter. The
cushions include numerous plurilocular sporangia but we have
seen only two or three unilocular sporangia, while in the European
plant, so far as we are acquainted with it, the unilocular sporangia
seem to be much more frequent.1. The North Carolina plant
seems to differ furthermore from the European in the smaller
cushions, in the smaller diameter of its shorter filaments, and in
having the sterile filaments, except their hairs, of about the same
length as the plurilocular sporangia instead of conspicuously
overtopping them. However, our plant has so many points in
common with the European endo-epiphyte on the same host that
we do not feel justified at present in considering it anything other
than a small form of that species. A section of the cushion does
not show the large colorless cells described and figured by Harvey
as belonging to its basal part, but we do not find such in European
specimens that we have examined; the exterior filaments spring
from a small endophytic cushion made up of cells that are scarcely
or not at all larger than those of the filaments, much as figured for
this species by Sauvageau.

In the North Carolina plant, the vegetative filaments of the
cushion are mostly 50-85 » long and 7-9 uw in diameter; many of
the shorter terminate in a hair 10-12 in diameter and often
reaching a length of 400 yu. The plurilocular sporangia are fusi-
form or filiform, mostly 30-50 uw long and 5.5-8.0 w in diameter;
many of them consist of a single series of loculi, but more of them
are two loculi broad except at base and apex, and rarely one may
show three loculi across the middle. The endophytic filaments
are of about the size of the epiphytic or a little stouter; they seem

1 According to Batters, loc. cit., the ‘‘paranemata with short articulations,’’ de-
scribed and figured by Harvey, are the plurilocular sporangia, as are also, in part at
least, the filaments figured by Areschoug. It seems to us probable that the plant
figured by Kiitzing (Tab. Phyc. 8: 1. pl. z. f. zr. 1858) under the name Phycophila
stellulata is not Elachistea stellulata (Harv.) Griff. The host, as figured by him, does not
look like Dictyota dichotoma, the sterile filaments differ from those of £. stellulata in
being conspicuously inflated near the middle, and the plurilocular sporangia are appar-
ently more elongate and filiform. We find plurilocular sporangia abundant in speci-

mens from Clare Island, Ireland, collected by A. D. Cotton, while in Crouan, Alg. Mar.
Finistére z and Desmaziére, Pl. Crypt. Fr. 1818, we have noted only unilocular sporangia.

L112 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

to prefer to follow the intercellular cavities between the cortex
and medulla; they are sometimes closely associated with the
endophytic filaments of the Streblonema solitarium, but may be
distinguished by their smaller diameter and shorter cells.

Elachistea stellulata was first described from southern England
but has since been reported also from France and from Ireland.
Its presence in American waters has not hitherto been noted, so
far as we know.

Erythrocladia recondita sp. nov.

Endophytic or pseudo-epiphytic, creeping in the superficial cell
walls of other algae; thallus consisting at first of free irregularly
radiating and irregularly branching filaments, soon becoming
more or less pseudoparenchymatous (essentially monostromatic)
in central parts, at length irregularly suborbicular and attaining a
diameter of 0.2-1.5 mm., or sometimes apparently broader through
confluence; ramification lateral or subdichotomous, the lateral
branches, especially in the younger plants, often divaricate; cells
(protoplasts) varied and irregular in form, in surface view mostly
oblong, quadrate, ovate, or panduriform, often curved, forked,
or irregularly I- or 2-lobed, 8-25 uw long, 3-12 » broad; pyrenoids
I—4 (usually I or 2), commonly 2.0-3.5 » broad and conspicuous;
monoecious; spermatia ovoid, 2—4 uw in diameter, exserted or sub-
exserted by slender stalks about I uw broad; carpogonia furnished
with a beak or trichogyne exserted about 4—8 yw; sporocarps forming
a single carpospore (or rarely 2), these ovoid, oblong, or irregular,
mostly 8-19 u in maximum diameter; non-sexual spores unknown.
[PLATE I2, FIGURES I-5; PLATE I3, FIGURE I.|

In the superficial cell walls of Dzctyota dichotoma, Beaufort,
N. C., W. D. Hoyt, September 7, 1906 (type)—associated with
Acrochaetium Hoytii; also on September 14, 1906, in smaller
quantity and less well developed; also in Dictyota dichotoma and

other algae and in stolons of hydroids, ‘in 1314-14 fathoms,”’
on reef 23 miles from Beaufort, Lewis Radcliffe, August 11, 1914.

In its earlier stages of development, Erythrocladia recondita
bears some resemblance to £. irregularis Rosenvinge,' described
from Danish waters on Polysiphonia urceolata, but it differs from
that species in being larger in all its parts (thallus finally 0.2—-1.5
mm. vs. 100u broad; cells 8-25 mu X 3-I2u vs. 7-II p X 3.5-
5.0 w), in its more conspicuous pyrenoids, and in its sexual mode

1 Kgl. Danske Vidensk. Selsk. Skrift. VII. 7: 72. f. 11, 12. 1909.

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. I13

of reproduction. We have hesitated long before deciding whether
to refer this North Carolina plant to the genus Colaconema of
Batters, the genus Erythrocladia of Rosenvinge, or to establish
for it a new genus, differing from both of the named genera in its
sexual method of reproduction. One of us (M. A. Howe) has
recently! expressed the opinion that Colaconema,’ or its type species,
C. Bonnematsoniae, is ‘“‘a close relative of Acrochaetium, near
which it was finally placed by Batters.’’ However, a reéxamina-
tion of a considerable number of specimens of Colaconema Bonne-
matsoniae, with special attention to the position and development
of the spores, convinces us that Colaconema is very closely allied
to Erythrotrichia and Erythrocladia, as has been suspected by
Rosenvinge. The ‘“‘monosporangia’’ of C. Bonnematsoniae are
mostly terminal on short branches and when their ‘“cup-like”’
base is not particularly well developed they may bear a superficial
resemblance to monosporangia of an Acrochaetium, but typically
the ‘‘sporangia’’ are subtended by a cup-like base, which may
embrace the sporangium or spore to its middle. And the spores
are not always terminal. They may be cut out from the side of
the terminal cell or from the side (often obliquely near the distal
end) of an ordinary or scarcely differentiated intercalary cell.
In origin and form their resemblance to the spores of Erythrotrichia
and Erythrocladia is most marked. Colaconema was described as
“living in the cell-walls of various algae,’ while Erythrocladia was
described as an epiphyte. But in specimens of £. irregularts,
the type of the genus Erythrocladia, which we owe to the courtesy
of Dr. Rosenvinge, its describer, the plant is clearly immersed
in the outer walls of its host, Polystphonia urceolata. In mode of
reproduction and in habit of life. there appears to be little differ-
ence between the type of Colaconema and the type of Erythrocladia.
However, in the type of Colaconema, the thallus is loosely fila-
mentous, with no observable tendency to radiate from any one
point as a center and no tendency to form a pseudoparenchyma;
the filaments are chiefly, but not wholly, confined to the outer
walls of the superficial cells of its host; these filaments or their

1 Mem. Torrey Club 15: 83. 1914.

2 Batters, Jour. Bot. 34:8. Ja1896. The homonymous genus Colaconema Schmitz,
in Eng. & Prantl, Nat. Pflanzenfam. 12: 452. 1907, has been renamed Colacopsis by
De-Toni, Syll. Alg. 4: 1170. 1903.

II4 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

branches may also penetrate to the inner cells of the cortex or
subcortex, so that the plant is not so completely confined to one
plane as is the case with the species that have been referred to
Erythrocladia. \n Colaconema (?) reticulatum Batters (loc. cit.)
endophytic in Desmarestia Dudresnayi, the vegetative conditions
are more as in Erythrocladia, but C. (?) reticulatum is not the
type species of Colaconema. ‘These considerations have led us to
prefer the generic name Erythrocladia' for our plant. Although
sexual reproduction has not hitherto been attributed to Erythro-
cladia, it would hardly seem that this character alone should be
considered sufficient ground for proposing a new generic group;
at least, so long as Erythrotrichia is allowed to hold a species
(E. carnea) in which non-sexual reproduction only is known and
another (/. obscura) in which both sexual and non-sexual modes
of reproduction have been described.

As to color of living or freshly collected specimens of Erythro-
cladia recondita, we can say little, as our material has been either
preserved in fluids or dried. To the best of our belief, however,
its color is a dilute or bluish olivaceous. This endophyte attracts
little or no attention when the surface of its host is being examined
microscopically in ordinary ways, but as soon as iodine (potassium-
iodide solution) is applied, it is differentiated with remarkable
distinctness. The protoplasts of the Erythrocladia take up the
iodine stain, becoming a purplish or bluish black, while the cells
of its host are scarcely affected. The carpospores and carpogonia
in particular have a special affinity for this stain and sometimes
they alone will be colored. We have found iodine a most valuable
reagent for differentiating small epiphytes and endophytes,
especially when they belong to the Rhodophyceae and inhabit
Phaeophyceae or Chlorophyceae. When both host and parasite
are Rhodophyceous, this reagent is not so effective, as both may
react in about the same way, but even in such cases, there are
often differences in color reaction that help to define the epiphyte
or endophyte. Preparations thus stained may be mounted in
glycerine or glycerine-jelly and preserved for considerable periods
of time, but, in our experience, the iodine staining is not perma-

1 The genus Neevea Batters (Jour. Bot. 38: 373. pl. 414. f. 18-22. 1900), endozoic
in Flustra foliacea, has been compared with Erythrocladia by Svedelius (Eng. & Prantl,

Nat. Pflanzenfam. 12: Nachtrage 196. 1911), but from Batters’ description and figures,
Neevea would appear to us to be more nearly allied to Goniotrichum.

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. II15

nent. Specimens, however, that have been mounted in glycerine
or glycerine-jelly may be washed off with water and restained
with iodine at any time.

Erythrocladia vagabunda sp. nov.

Endophytic or pseudo-epiphytic, creeping in the superficial cell
walls of other algae; thallus consisting chiefly of irregularly
branching, uniaxially elongate or irregularly radiating filaments,
finally spreading over areas 0.75-2.25 mm. long or broad, often
anastomosing ,or pseudo-anastomosing, and commonly forming
here and there small irregular pseudoparenchymatous patches
mostly 2-6 cells broad; ramification mostly lateral, rarely subdi-
chotomous, often divaricate or rectangular; cells (protoplasts)
for the most part irregularly oblong in surface view, often curved
or I- or 2-lobed, 9-40 u long, 6.5-15 uw broad; pyrenoids 1-4 (usually
I or 2), 2-3 broad; monoecious (?); sporocarps forming single
carpospores (rarely 2?), these ovoid, oblong, or irregular, mostly
12-25 u in maximum diameter; non-sexual spores unknown.
[PLATE 12, FIGURES 6—I1; PLATE 13, FIGURE 2.]

In the superficial cell walls of Dictyota dichotoma, dredged ‘‘in
1314-14 fathoms,” Lewis Radcliffe, August 11, 1914; associated
with Acrochaetium affine, Microchaete nana, Elachistea stellulata,
Streblonema solitarium, Erythrocladia recondita, etc.

Erythrocladia vagabunda is evidently a close ally of E. recondita,
but appears to differ in its straggling, obviously filamentous
habit, in its more rectangular branching, in its forming pseudo-
parenchyma, if at all, in small irregular scattered patches instead
of in a single central area, and in having cells of nearly twice the
average diameter of those of E. recondita. It was our first im-
pression that it might be considered a variety of E. recondita,
connected perhaps with its deep water habitat, but we finally
observed that it was associated, without intergrading, with a
more minute, smaller-celled endophyte, the free filaments of which
radiate from a pseudoparenchymatous center. This smaller plant
we take to be the true E. recondita, very slightly modified by its
deeper habitat. When iodine is applied, the protoplasts of this
smaller plant take a darker blue-black or violet-black color than
do those of the larger E. vagabunda. The two plants are shown
side by side and more or less intertangled in our photograph.

With the more limited material at our disposal, we have not
been able to demonstrate the sexuality of E. vagabunda so satis-

I16 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

factorily as in the case of E. recondita, but from the general simi-
larity of the supposed carpogonia and sporocarps to those of
E. recondita we feel no doubt as to its existence. In two instances,
we have seen a supposed spermatium resting on the general
surface above a supposed carpogonium. We have not observed
any carpogonium beak or trichogyne and think it must be only
slightly developed, if present at all.

The partly endophytic base of Acrochaetium affine, which some-
times develops short endophytic filaments or rhizoids, is occa-
sionally found in such close contact with Erythrocladia vagabunda
that it requires careful observation to satisfy one’s self that the
two things are not in organic continuity. The iodine stain, how-
ever, is an effective help in differentiating the two, the protoplasts
of the Acrochaetium reacting with a reddish brown rather than a
violet coloration.

Acrochaetium infestans sp. nov.

Endo- and epizoic, minute; interior filaments tortuous, intri-
cate, serpentine, or labyrinthine, mostly 2.0-5.5 » in diameter,
thin-walled, the branching very irregular, lateral, subdichotomous,
or very rarely opposite, commonly divaricate from near the middle
of a cell, the branches often subcircinately reflexed or inflexed, the
interior cells mostly 12-60 w long, 3-18 times as long as broad,
commonly curved or contorted and of irregular or fluctuating
diameter, the terminal cells of branches often enlarged, subhamate,
irregularly clavate, or subdivaricately forking, sometimes attaining
a diameter of 7-8 p, or, rarely, interior filaments forming a sort
of pseudoparenchyma, with irregular cells sometimes 10-13 yu
broad; chromatophore small, substellate or irregularly discoid,
near the center of the cell or subparietal, showing a single pyrenoid;
sporangiiferous filaments external, up to 90m high (or 2304,
including hairs), the simpler consisting of a single pedicel cell
bearing 1-3 sporangia (or, very rarely, the exserted sporangium
sessile on an endozoic filament), the larger showing I-9 short,
1-3-celled, rarely secund branches, the cells 4.5-6.5 » in diameter,
I-2 times as long as broad; hairs commonly present on the larger
external filaments, flexuous and attaining a length of 125-170 yp;
sporangia terminal or lateral, solitary, binate, or ternate, ovoid
or ellipsoid, 10-14 p X 6.0-8.5 yw. [PLATE 14.|

In and on the stalks, stolons, and less commonly hydranths of
small campanularian hydroids (perhaps representing more than
one genus) attached to Dictyota dichotoma and other algae, dredged

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N: C. I 17

in 1344-14 fathoms of water on reef about 23 miles off shore from
Beaufort, North Carolina, August 11, 1914, by Lewis Radcliffe.
The endozoic parts are embedded principally in the inner layers
of the perisarc of the stalks, stolons, and occasionally the hyd-
ranths.

Acrochaetium infestans doubtless finds its nearest ally in Chan-
transta endozoica Darbish. (Ber. Deutsch. Bot. Ges. 17: 13-17.
pl. I. 1899), originally described as occurring in a bryozoan,
Alcyonidium gelatinosum, on the southern coast of Ireland, and
since reported also from Denmark by Rosenvinge (Kgl. Danske
Vidensk. Selsk. Skrift. VII. 7: 128. 1909). From this species,
as described and figured by Darbishire, Acrochaetium infestans
appears to differ in having the diameter of both immersed and
exserted filaments averaging about one half as great, in the much
more tortuous, more irregularly branched interior filaments, the
more curved and irregular cells of which are actually, on the
average, two or three times as long, and relatively to their width,
four to six times as long, as in the European species. The spor- °
angia of Chantransia endozoica, as figured by Darbishire, are only
slightly broader than the subtending sterile cells; in A. infestans,
the mature sporangia are nearly twice as broad as the subtending
cells. Darbishire noticed one possible hair in his C. endozoica,
but was not sure that it really belonged to the organism in question.
In Acrochaetium infestans, the larger exserted filaments commonly
show hairs of remarkable length.

Acrochaetium infestans is associated with various mostly smaller
algae that penetrate the hydrozoan little if at all. The more
common and conspicuous of these are Acrochaetium affine and a
closely adherent filamentous blue-green (Phormidium sp.?), the
latter with trichomata 0.75-1.5 4 in diameter and cells mostly
I-2 (34-3) times as long as broad. The interior parts of the
Acrochaetium infestans are, in our formalin-preserved material at
least, so nearly colorless, and the plant in general is so small that
it might easily escape observation if one did not happen to empha-
size its existence through the use of differential stains. By
applying iodine (potassium-iodide solution) the little plant is
thrown into bold relief, its protoplasts becoming violet-red or
brownish crimson, while its host becomes a light yellowish
brown.

118 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Acrochaetium affine sp. nov.

Epiphytic, 1.0-3.5 mm. high, from a large persistent basal cell
(spore), this subglobose or ellipsoid, mostly 14-26 w in diameter,
finally becoming subpyriform and 20-33 » high through the de-
velopment of a subcylindric obtuse or truncate foot penetrating
the host for about 10-24 4, the basal cell remaining simple or
occasionally developing one or more smaller accessory cells, or
sometimes sending out short creeping, often more or less immersed,
filaments 2-5 cells long, these very rarely forming a small imperfect
basal disc, the secondary basal cells often sending up erect fila-
ments; erect primary filaments I-4 (usually 2 or 3) from the
primary basal cell, 6-14 u in diameter, often subdichotomous or
subtrichotomous at the distal end of the first cell, erect filaments
from secondary basal cells 1-4 (when present), commonly more
slender, 4-8 » in diameter, all filaments somewhat rigid below,
becoming flexuous above, rather sparingly and irregularly branched,
the ramification subdichotomous or distinctly lateral, ultimate
branches 3.0-5.5 u in diameter, mostly elongate-virgate; terminal
hairs often present, but rather inconspicuous; cells of filaments
cylindric, firm-walled, mostly 3—9 times as long as broad; chromato-
phore parietal, usually thin and inconspicuous, single or fragmented,
pyrenoid lateral; monoecious; antheridia usually close to the pro-
carp, lateral or latero-terminal, solitary or in groups of 2 or 3;
cystocarps (frequent) mostly 3-8-spored, carpospores 13-26 yu
< 8-18 4; sporangia (uncommon) monosporous, occurring on
sexual plants (sometimes at least), lateral on one-celled pedicels,
lateral and sessile, or sometimes terminal on main branches,
18-27 uw X 10-18 yw. [PLATE 15.]

On Dictyota dichotoma, dredged “‘in 1314-14 fathoms,” Lewzs
Radcliffe, August 11, 1914; accompanied by Mucrochaete nana,
Streblonema solitarium, Elachistea stellulata, Phaeostroma pusillum,
Erythrocladia vagabunda, E. recondita, etc.

Acrochaetium affine is related to A. Hoytii Collins,’ described
as an epiphyte on Dictyota dichotoma from the Beaufort region, to
A. unipes Berg.,? described as an epiphyte on Dictyota linearts
from St. Croix, and to A. robustum Berg.,® described as an epiphyte
on Sargassum vulgare from St. Thomas. It seems possible that a
carefully conducted series of cultural experiments, with a repro-
duction, if practicable, of the natural growth conditions of these
four alleged species, might be able to show that all four represent

1 Rhodora 10: 134. 1908.

2 Mar. Alg. Danish West Indies 2: 35. 1915.

3 Loc. cit. 40.

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, ING Ge ty nO

conditions of a single polymorphous species. However, such
experiments would be difficult to carry out and what they might
prove is at the present time purely conjectural. The facts remain
that our plant, taken as a whole, differs in several particulars
from any one of the three plants named, and that, apart from the
priority of Acrochaettum Hoyti and the apparent identity of the
hosts of A. Hoytit and A. affine, there seems to be no compelling
reason for the association of our plant with any one of the three
names mentioned rather than with any other of the three. Under
these circumstances it seems justifiable to give our plant a new
specific name, which, like most new specific names, is a tentative
one at best.

From Acrochaetium Hoyti, A. affine differs in its larger size
(1.0-3.5 mm. vs. 0.3-1.3 mm. tall), in its sparing and irregular
ramification with branches mostly long and flexuous (A. Hoytiz
commonly has numerous short, mostly 1—5-celled branches and
branchlets, sometimes springing from nearly every cell of the
main axes, often once or twice compounded in a similar fashion
and arranged in a corymbose-secund manner), in the usually
greater diameter of the primary filaments (6-I4 mu vs. 5-74),
in the relatively longer more cylindric cells (mostly 3-9 vs. 2-4
diameters long), in the usually more imbedded primary basal
cell, in the occasional formation of secondary basal cells, which
now and then are so numerous as to constitute a small basal disc,
in the larger (18-27 » X 10-18 m vs. II-I5 mu X 5-6yu) and in-
frequent sporangia, and in the relatively abundant cystocarps.
The cystocarps of A. Hoytit were not observed by Mr. Collins.
We have seen a very few cystocarps in A. Hoytiw, but have not
seen antheridia or procarps. The sporangia of A. Hoytw were
described as on one-celled pedicels, but we find them often sessile
also.

From Acrochaetium untpes, which we know only from Dr.
Bgrgesen’s description and figures, A. affine would appear to differ
in having in mature conditions, except in rare cases, 2—4 erect
primary filaments. These are commonly subdichotomous or
subtrichotomous close to the base, so that at first sight the effect
of having 4-12 primary filaments is produced, while A. unipes
has a single erect primary filament with apparently only lateral
branching. No secondary basal cells are attributed to A. untpes.

I20 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Sporangia are the only form of reproductive organs described for
A. unipes and these would appear to be more uniformly uniseriate
or secund than we have observed them to be in A. affine.

From Acrochaetium robustum, which also we know only from
Dr. Bérgesen’s description and figures, A. affine would appear to
differ in being a taller plant (I-3.5 mm. vs. I mm. or less), in having
usually a single basal cell instead of a basal disc and in the larger
sporangia (18-27 4 X 10-18 vs. 12-16u XI1p). No cysto-
carps are known in A. robustum, but the sporangia are abundant.

Intermingled with the undoubted Acrochaetium affine we have
seen a few plants with a filamentous or rhizomatous endophytic
base, the original spore not differentiated and the basal filaments
apparently creeping within the outer cell walls of its host and
sending up erect external filaments here and there. We are
inclined to believe that they represent a condition of the plant
described above as A. affine, but not being wholly convinced as
to their identity, we have endeavored not to include them in
writing our diagnosis of this species. If they really represent a
form of A. affine, they would indicate a greater range of vari-
ability in the basal parts of an Acrochaetium than recent writers
on this genus have assumed to be possible. If our material
includes two species, it is possible that our figures 5 and 14, which
seem to show scarcely enlarged original basal cells, are to be re-
ferred to the species that we are leaving undetermined. Our
figure 14, by the way, is rather suggestive of Bérgesen’s figure
(loc. cit. 51. f. 53) of the basal part of his Acrochaetium Hypneae.
In the matter of endophytic basal filaments, care must be taken,
in the case of A. affine, not to confuse the base of this plant with
the filaments of the endophytic Erythrocladia vagabunda and
E. recondita, with both of which it is often very closely associated.
Young few-celled filaments of FE. recondita, in particular, often
closely encircle the partly endophytic bases of the Acrochaetium
and might easily be taken to be a part of it. On staining with
iodine, however, the protoplasts of the Acrochaetium become a
reddish brown, while those of the Erythrocladia become violet-
purple or almost black.

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. I2I

Explanation of plates 11-15

PLATE II

1-9. Phaeostroma pusillum

1. Margin of thallus, ‘showing discrete repent filaments, plurilocular sporangia,
hair, etc.

2. Enlarged detail, showing immature plurilocular sporangium, chromatophores, etc.

3. A mature plurilocular sporangium in obliquely longitudinal view.

4. A mature plurilocular sporangium viewed from above (end view).

5. Margin of thallus (more compact than that shown in Fig. 1), with unilocular
sporangia. A sorus at a and the beginning of a sorus at b.

6. Enlarged detail of thallus, showing chromatophores and unilocular sporangia
as seen from above.

7. A young unilocular sporangium, viewed from above.

8. The beginning of a sorus, viewed from above.

9. A mature sorus of unilocular sporangia, viewed from above.

Figures 1 and 5 are enlarged 245 diameters; 3 and 4, 670 diameters; 2, 6, and 7-9,
1040 diameters.

10-16. Derbesia turbinata

10. Apex of thallus, showing a young lateral branch.

11. Lateral branching, or ‘‘unequal dichotomy.”

12. A dichotomy of thallus.

13-16. Usual forms of sporangia. Fig. 13 shows a short pedicel cell; 15, a longer
one; in 14 and 16, no septa have appeared.

Figures 10-12 are enlarged 81 diameters; 13-16, 162 diameters.

PLATE 12

1-5. Erythrocladia recondita

1. Portion of thallus near margin, viewed from above, showing outlines of proto-
plasts and of pyrenoids and also outlines of the cortical cells of its host.

2 and 3. Portions of cross sections of the endophyte and its host, showing the more
or less exserted spermatia (spm) and the immersed vegetative cells.

4. Portion of a cross section, showing a carpogonium with exserted trichogyne.

5. Portion of pseudoparenchymatous thallus, viewed from above, showing proto-
plasts of vegetative cells, spermatia (spm), carpogonium (cpg), and sporocarps (spcp ).

Figures are all enlarged 670 diameters.

6-11. Erythrocladia vagabunda

6. Portion of thallus, viewed from above, showing outlines of protoplasts and pyre-
noids and also outlines of the cortical cells of its host. The cells, here enlarged 415
diameters, appear of about the same size as those of E. recondita when enlarged 670
diameters (Fig. 1).

7. Portion of thallus, showing three vegetative cells, six sporocarps (spc), and five
cavities from which carpospores have been discharged.

8 and g. Portions of thalli, showing vegetative cells and sporocarps (spcp).

10. A single carpospore lying on the surface of its host, in the outer walls of which
it is already partially immersed.

11. A young filament (four-celled stage), viewed from above.

Figures 6, 8, 9, and 11 are enlarged 415 diameters; 7 and 10, 670 diameters.

122 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

12-17. Muicrochaete nana

12. A young filament, prostrate but beginning to turn upward at apex. In this
figure and the next the thickness and distinctness of the vagina are somewhat exag-
gerated.

13. An older and normally curved filament, showing two basal heterocysts, a rare
or occasional character.

14. An unusually straight, apparently mature, filament.

15. Another filament with a curve of a frequent form near base.

16. Apex of filament shown in Fig. 15.

17. Base of filament shown in Fig. 15.

Figures 14 and 15 are enlarged 245 diameters; 12, 13, 16, and 17, 670 diameters.

PLATE 13

1. Erythrocladia recondita. A photograph of the endophyte, made after staining with
iodine. The larger darker cells are sporocarps. Enlarged 160 diameters.

2. Erythrocladia vagabunda. A photograph of the endophyte, made after staining
with iodine. Some of the larger cells are sporocarps. A small colony of E. recondita,
staining more deeply and having smaller cells, is shown near B at the lower right-hand
corner, where it is more or less intertangled with the E. vagabunda. Enlarged 160
diameters.

PLATE 14
Acrochaetium infestans

I. Endozoic filaments of the usual form, with two short exserted filaments. In the
endozoic parts the outlines of protoplasts only (for the most part) are indicated, the
cell walls being almost invisible.

2. An exserted sporangium sessile on an interior filament.

3- An exserted filament of three cells, one of which is a sporangium and another of
which is probably an immature sporangium.

4. An exterior filament, with short branches, short hairs, and a single lateral spor-
angium.

5. A single typical cell of an interior filament, showing chromatophore, pyrenoid,
etc. :

6. Exterior filaments, showing sporangia in terminal clusters of three, and also one
lateral sporangium.

7 and 11. Short exterior filaments.

8. A branched exterior filament, showing lateral and terminal sporangia. One of
the emptied lateral sporangia is apparently being refilled or regenerated from the sup-
porting vegetative cell.

g. A short exterior filament, showing regeneration of a terminal sporangium.

10. Part of a plant, showing mode of branching and tortuous course of a part of an
interior filament, etc.

12. An unusually long exterior filament, showing long hairs and short secund branch-
lets (solitary or geminate).

Figure 5 is enlarged 1,040 diameters; the others, 670 diameters.

PLATE 15
Acrochaetium affine

1. A spore attached to margin of the Dictyota thallus.
2. A spore that has developed a small accessory repent basal cell and is also be-
ginning to send up an erect filament.

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE II

I-9. PHAEOSTROMA PUSILLUM Howe & Hoyt

10-16. DERBESIA TURBINATA Howe & Hoyt

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 12

I-5. ERYTHROCLADIA RECONDITA Howe & Hoyt

6-11. ERYTHROCLADIA VAGABUNDA Howe & Hoyt
12-17. MIcROCHAETE NANA Howe & Hoyt

Mem. N. Y. Bot. GAnDEN VOLUME VI, PLATE 13

| he
ah ee

{ ERYTHROCLADIA RECONDITA Howe & Hoyt
2. ERYTHROCLADIA VAGABUNDA Howe & Hoyt

N. Y. Bot. GARDEN

Mem.

SES

ZO ~

Sass

HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N.C. 123

3. Base of a mature plant, showing simple basal cell and two erect filaments, each
of which branches from its lowest cell.

4. Base of a similar, though larger plant, with four primary erect filaments, each
branched at its base. A small cystocarp at a.

-5. Base of a plant showing a scarcely enlarged basal cell, short repent basal fila-
ments, and a single erect filament which has two branches from its lowest cell.

6. A vertical section through the base of a plant, showing a few small accessory
cells that partly cover the primary basal cell.

7. Base of a plant showing accessory basal cells and three coarse and three slender
erect filaments, none of which branches from its lowest cell.

8. Base of a plant with accessory basal cells, and erect filaments of various sizes.

g. Base of a plant that has developed a small imperfect basal disc, with the original
spore manifest.

10. Optical section of the margin of the Dictyota thallus, showing base of young plant
with a single immersed basal cell and a single erect filament.

11. Optical section of the base of a plant, showing subpyriform semi-immersed
primary basal cell and several superficial smaller secondary cells, some of which send
up erect filaments.

12. Section through the margin of the Dictyota thallus, showing single subpyriform
basal cell with penetrating foot.

13. Base of a detached plant showing primary basal cell, its penetrating foot, three
erect filaments, and two small accessory basal cells.

14. Section of margin of the Dictyota thallus, showing four basal cells of approxi-
mately equal size that are more or less endophytic. The partly overlying cortical cells
of the Dictyota are for the most part disintegrated, but this may have been accomplished
by agencies other than the Acrochaetium.

15. A sporangium terminal on a main branch.

16. Sessile lateral sporangia.

17. A sporangium on a one-celled pedicel.

18. Procarp and antheridia.

19. An older procarp with no obvious antheridia in its vicinity,

20. A cystocarp.

21. A typical cell from one of the coarser filaments, showing chromatophores and
parietal pyrenoid.

22. A typical cell from one of the more slender filaments.

Figures 1-17 are enlarged 415 diameters; 18-22, 670 diameters.

* Te Fee Unst La
SORE Peed tbh rie:
«3 pattce Seu sive
erage} pense it aan. Ay

He Wire vente 4 Sih) Aware
¢

heats 1s Ven

> . 7) > >
Opie Sh hay cee fet tikes PDS TL. |
aioe of ee rus [shee Be
4 s és -t a ‘ Ear he

* UE tv fee sa TG ey Rida icbatRe
feo: 991 GE's an cite al hadi deo ea
Ahan ike -s - Bs tte Saal CORN ieee
er zs cork be ive AA mR: —e vite

. a, Jae hes r
a) me x = &s; fs :

+4 j cent ne, i tcate

; Tibet. e . ; as ¥ = €, ese PE ge

s : niger, 12 pe
=
ia
1
rie
e
i as

SOMATIC AND REDUCTION DIVISIONS IN
CERTAIN SPECIES OF DROSERA

MICHAEL LEVINE

Columbia University
(WITH PLATES 16-19)

Rosenberg’s work on the cytology of the so-called natural
hybrid Drosera obovata has raised some of the most interesting
points so far presented in the study of the chromosomes in hybrid-
ization. According to Rosenberg (’03, ’04, ’09) Drosera longi-
folia has forty chromosomes in the somatic cells, which fuse in the
pollen mother-cell and embryo sac mother-cell and form twenty
bivalent chromosomes. In Drosera rotundifolia he finds only
twenty somatic chromosomes and ten bivalent chromosomes in
the germ cells. He reports that these chromosomes are large
and readily distinguishable from those in D. longifolia. In D.
obovata, which has been considered a natural hybrid between
D. longifolia and D. rotundifolia, he finds that there are invariably
thirty heteromorphic chromosomes in each somatic cell, while in
the pollen mother-cell or embryo sac mother-cell there are ten
double chromosomes and ten single ones. Rosenberg claims that
D. obovata received twenty chromosomes from D. longifolia and
ten from D. rotundifolia. The pairing of the homologous parent
chromosomes results in the formation of two kinds, namely single
ones and double ones. In the heterotypic division of D. obovata
the ten double chromosomes separate, ten dyads going to each
pole. Rosenberg finds that the ten single ones are distributed
unevenly to the poles so that some nuclei receive as many as
eighteen chromosomes while others receive only twelve. Not infre-
quently one or more of the single chromosomes are left on the
spindle. Inthe second division the nuclei may receive from thirteen
to sixteen chromosomes each, while the belated chromosomes form
dwarf nuclei which eventually disintegrate or form dwarf pollen
grains. All the pollen in the hybrid is sterile.

125

126 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The appearance of lagging or belated chromosomes has been
described for a great number of species and the phenomenon is
associated with varying degrees of abnormality in the general
behavior of the cells in which it occurs. Whether in the case of
D. obovata such bodies are really chromosomes is certainly a
question and my studies, to be described below, furnish some
interesting suggestions in this connection.

- Strasburger (’82) and later Juel (?97) have observed undoubted

chromosomes on the spindles after the completion of the reduc-
tion divisions of the pollen mother-cells in Hemerocallis fulva.
Strasburger and Juel both observed that these belated chromo-
somes become surrounded by nuclear membranes and form dwarf
nuclei and later dwarf pollen grains. Juel emphasizes the fact
that every chromatic mass can become an individual cell and
later divide. It must be remembered that already Wimmel (’50)
for Fuchsia, Hofmeister (’?48, ’61) for Passiflora caerulea and
Iris pumila, Tangl (?82) for Hemerocallis fulva, Wille (?86) for
twenty-three species of different flowering plants had found that
a number of pollen grains less and greater than four may arise
from a single pollen mother-cell by failure of the daughter pollen
mother-cells to divide or by subsequent division of the cells of
the tetrad. These views were later shared by Miss Lyon (’98) for
Euphorbia corollata and Fullmer (’?99) for Hemerocallis fulva.
Beer (’01) confirmed Juel’s conclusions. He re-investigated
Wimmel’s results on Fuchsia and found that some chromosomes
lag behind on the spindle after the first division and finally give
rise to dwarf nuclei. Less frequently these chromosomes fail to
become nuclei and then they rapidly disintegrate.

Latour (’08) in his study of the development of pollen of
Agave attenuata noticed groups of chromosome-like bodies in the
cytoplasm and on the spindle in the first division of the pollen
mother-cell. These bodies look in all respects like chromosomes.
Each body soon becomes enveloped in a’ nuclear membrane and
may then disintegrate, or several of them may unite to form a
larger nucleus or they may join the body of the main nucleus.

Interesting abnormalities in division of the male germ cells
have likewise been observed in a number of hybrids. The anoma-
lies seem to be closely related to the appearance of chromosome-
like bodies. Juel (’00) investigated the cytology of the hybrid

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 127

Syringa rothomagensis and its parents \S. vulgaris and S. persica.
He found that the reduction divisions in the hybrid were abnormal.
Invariably chromatin or chromosome-like bodies appear in the
cytoplasm during division stages. These bodies take the chroma-
tin stain and become invested with a nuclear membrane. The
origin of these bodies is not clear. Juel believes that these bodies
arise from the amitotic division of the nuclei of pollen mother-
cells which disintegrate. Juel holds that the sterility of pollen
is due to the abnormality of the tetrad division. Tischler in his
interesting papers (’05, ’06, ’08, ’10) on the causes of the sterility
of pollen in hybrid plants finds that in Rzbes Gordonianum the
chromosomes are irregularly distributed in the first division of
the pollen mother-cells so that more than two daughter nuclei
are formed. In sterile Bryonia hybrids and in three varieties
of Musa sapientum he described similar conditions. In the
former case he believes that the abnormality in the first and
second divisions of the pollen mother-cells is similar to that in
Hemerocallis fulva (Juel, ’97). In Potentilla similar conditions
appear, yet in both Bryonia and Potentilla normal pollen is also
found. It is of interest to note that in the three varieties of
banana, Dole, Radjah Siam, and Kladi, there are eight, sixteen
and twenty-four chromosomes respectively.

Gates (’07) in a study of hybrids between Oenothera lata
and O. Lamarckiana described and figured chromatic bodies in
the cytoplasm of the pollen mother-cells during division. He
observed the complete sterility of certain anthers of a flower and
associated this condition with the appearance of these bodies.
In a later paper (?14) Gates and Thomas reported their work on
Oenothera lata and O. semilata. Here they found 15 chromosomes in
the somatic divisions and that while in the pollen mother-cell the
extra chromosome behaved differently—it most frequently was
left behind on the spindle. Gates believes that the union and
segregation of chromosomes tends to be in two numerically equal
groups.

Geerts (’09, ?11) in a cross between Oenothera lata and O. gigas
found in the hybrid a condition similar to that observed by
Rosenberg in D. obovata. The male gametes have fourteen
chromosomes and the female gametes have seven chromosomes
and the hybrid twenty-one, in two sets, seven and fourteen. In

128 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the equatorial plate stages of the heterotypic division Geerts
claims to recognize seven double and seven single chromosomes.
The double chromosomes divide and go to their respective poles,
while four of the single chromosomes may go to one pole and
three to the other. Not infrequently one or more of the single
chromosomes fail to reach the poles and are left on the spindle.
In the second division the three or four single chromosomes may
divide but more commonly they disintegrate. Here again a
_ chromosome may be left on the spindle and form a dwarf nucleus.
Still, Geerts reports that pollen grains with ten or eleven chromo-
somes are not uncommon. Geerts regards his results as in perfect
accord with that of Rosenberg on Drosera obovata and as opposed
to those of Gates (?09) on the same hybrid. In both heterotypic
and homoeotypic divisions of male cells of Oenothera gigas, Davis
(711) found chromosomes that fail to reach the poles and form
supernumerary nuclei.

It is plain that the cases of chromosomes which fail to reach
the poles are not confined to hybrids with parents having the
unequal number of chromosomes.

In the cases so far considered there is a question as to whether
the bodies appearing in the spindle in early telophase are really
chromosomes. It is well known, however, that other deeply
staining bodies may be found on the spindle in both the reduction
and somatic divisions. Zimmerman (’93, ’94) reported the ap-
pearance of bodies on the spindle and in the cytoplasm which in
appearance and staining reaction agreed in all essentials with
the nucleoli of the resting nuclei. Zimmerman believed that
these bodies came from the nucleolus as a result of its disinte-
gration during karyokinesis and called them extranuclear nucle-
oles. He held further that these bodies go into the daughter
nuclei and fuse to form a new nucleole—a view subsequent in-
vestigation has not confirmed. Allen (’05) in Lilium canadense
described and figured extranuclear nucleoles in the prophases of
the pollen mother-cells. These bodies he claimed disappeared
by the time spindles were formed. They reappeared and later
were numerous in the equatorial plate stage. Gregory (’05)
studied similar bodies in the fertile variety of the sweet pea,
Emily Henderson. He found that the nucleolus fragments and
spherical bodies, three to four in number, appear in the cytoplasm

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA_ 129

when the nuclear membrane disappears. The fate of these bodies
he was unable to determine.

Beer (712) reported that he found in the cytoplasm of Crepis
taraxactfolia and C. virens a number of deeply stained granules
which he refers to as chromatic droplets. In Matricaria Chamo-
milla similar bodies appear a short time after the heterotelophase.
Beer believes these bodies are derived from portions of the nucle-
olus which have passed through the nuclear membrane. Similar
phenomena have been described by Farmer and Digby (’10) for
Polypodium vulgare. Many have claimed that chromatin may be
extruded and appear as deeply staining bodies in the cytoplasm.
Some claim for these bodies very important functions in the activi-
ties of the cell, others maintain that they are mere artifacts.
Digby (’09, ’10, ’12, ’14) in the study of spermatogenesis of
Galtonia candicans, Crepis taraxactfolia, and Primula kewensis found
that during synapsis part of the nuclear network or nucleolar
substance passes through the nuclear membrane and forms a
rounded or finger-like projection on the surface of the nucleus
and may finally pass into the cytoplasm of the adjacent cell.
These extruded masses become separated from the parent nucleus
and become surrounded by a clear hyaline area and then take on
the outward appearance of a nucleus; but later they disappear.
Similar observations were made by Rosenberg (’09) for Drosera
longifolia and Crepis virens. He claims that these extrusion
substances are nothing more than the results of poor fixation.
Koernicke (’01) claimed that these bodies indicate that the
anther is in an abnormal condition at the time of fixation. Gates
(711) in his study of Oenothera gigas and O. biennis described the
escape of chromatin from the nucleus of the pollen mother-cell
into the adjacent cells. His figures correspond with those of
Miss Digby. Carruthers (?11) claimed to find similar extrusion
substances from the nuclei in the young asci of Helvella crispa.
West and Lechmere (’15) described what they called budding of
the nuclei in the pollen mother-cells of Lilium candidum. They
claim that the nucleolus takes no part in the formation of these
nuclear protuberances and that these bodies are normal and may
represent the discharge of waste products of the cell.

In studying the chromosome number and reduction divisions
with a view to determining whether wild hybrids exist also in

130 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

America I was struck by the appearance, in a great number of
sections, of chromosome-like bodies on the spindle and in the
cytoplasm of the pollen mother-cells during the late telophases
of both the first and second divisions. These bodies in their
general characteristics resemble the belated chromosomes de-
scribed and figured by Strasburger, Juel, Tischler, and others.
These bodies were especially well shown in Drosera rotundzfolia.
Studies were also made of Drosera intermedia Hayne, D. filiformis,
D. binata, and D. longifolia. Numerous plants of the first three
species mentioned were collected in the bogs at Lakehurst, N. J.
during the summers of 1913—14—15. Flowers of all sizes were
fixed in a number of fixing solutions such as Carnoy’s, Bouin’s,
Merkel’s, and Flemming’s mixtures. The best results were ob-
tained with Flemming’s medium fixative. Flowers of D. binata
were obtained from plants cultivated at the New York Botanical
Garden. Similar fixing solutions were used on these flowers.
My material of D. longifolia,! of which I had relatively few plants,
was kindly sent to me by Professor John Davidson from Vancouver
Island. Its identification is unquestionable as shown by com-
parison with critically determined material in The New York
Botanical Garden. The flowers were sent to me already fixed in
Carnoy’s, Merkel’s, and Flemming’s solutions. Living material
available for identification purposes was also sent. A number
of stains were used but Flemming’s triple stain gave the best
figures.

The nuclear phenomena are so much alike in the species studied
that I shall treat of them collectively except where special mention
is necessary. To make more certain the interpretation of my
observations on the reduction divisions I have also studied the
somatic divisions in the ovary and stamens.

Somatic divisions —The vegetative cells of the flower as well
as the young archesporial cells are very favorable for study though
the nuclei are not large. In the resting state the nuclear material
is made up of a fine linin network with a number of minute but
sharply defined chromatic bodies (Fic. 1). These bodies are

1 Through the kindness of Professor N. Wille, who sent me herbarium specimens of
the Norwegian Drosera longifolia and D. intermedia Hayne, I was able to study and

compare these two species with our American forms. I find these species quite distinct
and readily separable, as maintained by Dr. N. L. Britton (’07).

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 131

undoubtedly like the prochromosomes of Rosenberg (’04) and
Overton (’05). With careful study their number can be fixed
at about twenty. In the case of D. longifolia, which is the species:
of special interest in view of Rosenberg’s contention that its so-
matic chromosome number is forty, I have been unable so far by
a study of the prochromosomes in the somatic cells to verify his
conclusion. In my preparations, however, the prochromosomes
were favorably shown in onlya few cells. |The prochromosomes stain
sharply with gentian-violet but other smaller granules which stain
faintly are also present. Thenucleolestainsarubyred. Not infre-
quently one can find a cell with two or three nucleoles. The cyto-
plasm stains a faint orange. In the cells of the anther wall the
cytoplasm is not at all dense and anumber of large vacuoles appear,
while in the immature pollen mother-cell the cytoplasm is densely
granular with few or no visible vacuoles. The prochromosomes
appear to spin out and forma spireme which fills the entire cavity of
the nucleus. The band isnarrow and seems to becontinuous. The
nucleole disappears, the spireme segments and twenty more or
less angular chromosomes can be counted before a bipolar spindle
can be recognized. In this stage also I had relatively little
material of D. longifolia and considerable difficulty was encoun-
tered in making a definite count. The nuclear membrane
disappears and the chromosomes are seen in equatorial plate
stage (Fic. 2). The spindles are like those described by Rosen-
berg (°99) for Drosera rotundifolia—some may be pointed while
others are broad-poled. In the early telophases of the somatic
divisions a rudimentary cell plate (Fics. 5, 6) is developed but the
incipient stages of the process were not observed. ‘The fibers at
the center of the spindle shorten as shown by Strasburger (’82),
Timberlake (’?00) and others. New fibers also appear which make
the spindle seem to bulge out until the diameter of the spindle
reaches across the width of the cell (Fics. 6-7). At the same
time the nuclear masses seem to approach each other (FIG. 6).
The cell plate continues to grow peripherally until it forms a
diaphragm cutting the cell in two (Fic. 8). In the later telophases
the chromosomes begin to anastomose and there seem to be lines
of flowage of material from each chromosome. The stain is taken
more deeply at the center of the mass while its intensity decreases
as the distance from the center increases. The flowage progresses

132 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

steadily until the chromosomes remain only as small granules in a
fine reticulated structure. In the case of the last premeiotic
division as described it may be clearly seen that the chromosomes
form the prochromosomes of the pollen mother-cells as Rosenberg
(709), Digby (?10), and others have claimed.

Reduction divisions —The pollen mother-cells were studied in
D. rotundifolia, D. intermedia, and D. filiformis. In my material
of D. longifolia the pollen grains were already mature so that the
divisions forming the embryo sac alone were available for chromo-
some counts.

D. filiformts is most favorable for the study of the pollen mother-
cells on account of the somewhat larger cells. The germ cell
nuclei are all provided with a single large nucleole and in it one
invariably finds one or more large vacuoles as shown by Martins
Mano (’05), Nichols (’01), and Digby (’08). These vacuoles
afford no evidence that chromatin is budding off from the nucleole
as suggested by Nichols, although in all species studied small
globular bodies may occasionally be seen lying in contact with
the nucleole as figured by Rosenberg (’09). The nucleole gen-
erally occupies a peripheral position in the nucleus and the prochro-
mosomes (FIG. 15) are scattered in a fine linin network. These
bodies are slightly elongated or rod-like granules which generally
lie in pairs in the periphery of the nucleus. The prochromosomes
are readily distinguishable from the other granular substances
which appear in the nucleus at this time by their deep gentian-
violet stain and their compact homogeneous consistency. By
close study there may be found all stages in the transformation
of the prochromosomes to form the leptoneme spireme. The
process is similar to that shown by Overton (’05) for Calycanthus
floridus. Two fine thread-like bands are formed, the leptoneme
spireme (FIGs. 26, 27, 28) as figured by Berghs (’05) for D. rotundt-
folia and later by Rosenberg (’09). The mature leptoneme spireme
can be clearly seen to be made up of two thin, parallel bands of a
homogeneous structure. In some stages these threads seem to
have fused and a single continuous spireme band appears (FIG. 16).
Occasionally this fused band may have a beaded appearance, as
shown by Rosenberg, Overton, and Allen. In this condition
there is no evidence of its bivalent nature. It is quite apparent
from the above that the pairing of the prochromosomes is to be
side by side.

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 133

By slow changes the spireme begins to contract and move toward
the periphery of the nucleus and the synaptic stage is formed.
All stages may be found in this contraction of the spireme. An-
thers in the same flower are found in different stages other than
synapsis. I cannot agree with Lawson (’11) that the synaptic
knot is not an active contraction of the chromatin thread. The
coils of the spireme can be readily traced in the early stages but as
the knot becomes smaller and smaller the difficulty is increased
but at no time is it impossible to trace the individual coils (F1Gs.
17-18). The nucleole is generally enclosed in the meshes of the
synaptic knot; that also helps to make the winding of the band
more difficult to follow.

As the chromatin mass emerges from the synaptic knot there
is a simultaneous shortening of the spireme and the pachyneme
spireme is formed. Drosera filiformis is particularly favorable
material for the study of this stage (see F1Gs. 29a, 290). When
the pachyneme is fully developed it may be seen to consist of a
number of loops which are evenly distributed through the nuclear
cavity. The band is homogeneous and while it occasionally shows
signs of a beaded structure it is as a rule very smooth. The
chromatin material of the spireme next seems to accumulate in
certain areas (FiG. 30) leaving clear spaces in the band between
them. This stage is followed by further contraction and thicken-
ing and finally the breaking of the spireme into a number of seg-
ments. as shown in Fic. 31. In Fics. 19, 32a, 6, c, we have the
representation of nuclei in diakinesis. The ten bivalent chromo-
somes are peripherally distributed. They are somewhat angular
and approximately all the same size. Occasionally the chromo-
somes appear quadripartite (Fic. 9). In the embryo sac mother-
cell of Drosera longifolia I have been able to observe the breaking
up of the pachyneme (Fics. 40a, 0) spireme. The cells are
large and the nuclei in sections 5 uy thick may be cut twice.
I have been unable at this stage also to determine the number of
chromosomes but I hope that in the coming summer with more
material this question can be definitely settled.

The nucleole in this stage stains a vivid ruby red and a number
of vacuolar areas are visible. The nucleole has in no way changed
except that it has increased in size. I must agree with Martins
Mano (’05) that there is no evidence here for the contention of

134 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Wager (’04), Gregory (’05), Nichols (’08), Darling (’09), and
others that the nucleole by budding forms chromosomes or
chromosome material. Fine fibers appear in close proximity to
the nucleus. I have not, however, found a definite felted zone.
In some sections there is only the faintest indication of fibers
present as shown in Fic. 32a, 6, c. I have not traced the pro-
gressive development of the spindle. The spindles in the first
division are larger but otherwise are like those of the somatic
divisions. The chromosomes form a very evenly arranged equa-
torial plate stage. FIG. 11 represents a polar view of a spindle
and ten chromosomes can be counted. The chromosomes are
quite angular and a definite longitudinal cleft divides the tetrads
into dyads (FIGs. 10, 20, 33). At this time no abnormalities
appear either in the cytoplasm or on the spindles. There is no
indication of extranuclear nucleoles or portions of displaced
chromosomes. FIG. I2 represents the dyads approaching their
respective poles. Each chromosome appears longitudinally split,
undoubtedly in preparation for the second division. After the
chromosomes have reached the poles the central spindle persists
in many cases and show all the peculiarities described by Went
(787) and Timberlake (’00). It is not uncommon, however, to
find radial fibers coming from the chromosome groups (FIG. 23)
and forming an irregular aster. Chromosome-like bodies now
make their appearance in the cytoplasm and on the spindle fibers.
I have observed them in Drosera rotundifolia, D. intermedia, and
D. filiformis and only during the division phases. In color, size,
and shape they remind one, however, of the belated chromosomes
of Strasburger (’82), Juel (?00), or the unpaired chromosomes of
the Drosera hybrid of Rosenberg (’04, ’09) and the Oenothera
hybrid of Geerts (’09). They bear perhaps an even greater
resemblance to the nucleole and look like the figures of extra-
nuclear nucleoles of Zimmerman (’93) and more recently Allen
(705) for Lilium. The size of these bodies varies; while some
of them are about the diameter of the chromosomes others are
smaller. They are spherical in shape but have a tendency to
become angular. By their staining reaction it is difficult to
determine whether they resemble more the chromosomes or the
nucleole. By a careful study of a great number of these stages
I am convinced that these bodies take a nucleolar stain. The

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 135

position of these bodies on the spindle, very close to the newly
formed nuclei, resembles that of the belated chromosomes shown
by Strasburger, Juel, Tischler, Beer, Gates, Davis, and others.
It is not at all probable that these bodies are chromosomes.
Their number is large in some cells and they show no tendency
to form central spindles or diminutive nuclei. One can count
from nine to ten chromosomes in the daughter nuclei at this
stage and as many as four equally large bodies lying in the spindle
(FIG. 23) in the same cell. It seems quite improbable also that
these bodies have a nucleolar origin. Their number and conse-
quently their volume is far greater than that of the nucleoli (see
Fics. 13, 34). Yet in the homogeneity of their substance and
their color with the triple stain they resemble nucleoles. That
they are precipitation products formed in fixation is also quite
out of the question. They appear in all three species mentioned
above with all the different fixative and staining methods used.
These bodies as a rule disintegrate shortly after the first division
but they may be left in the cytoplasm until the completion of the
second division, when the entire protoplast disintegrates. No
evidence appears that these bodies are present at any stage in the
second division earlier than the late telophase.

In the second or homoeotypic division the spindles (Fic. 14)
are considerably smaller and are variously situated with respect
to each other. The poles are usually single-pointed and the
spindles in general are like those of the heterotypic division.
The chromosomes are equally distributed on the spindle in the
equatorial plate stage. In the early anaphase as shown in FIG. 14
they have split lengthwise and are beginning to move apart. The
attachment of the mantle fibers is almost in the middle of the
chromosome, so that U-, V- and L-shaped figures result. Although
these chromosomes are small, in polar view twenty monads may
be clearly seen.

While the majority of pollen mother-cells in anthers at a slightly
older stage show three nuclei a considerable number appear with
two and four. It is quite evident that in pollen cells with three
or four nuclei simultaneous division or quadripartition of the pollen
mother-cell must follow. In the case where three nuclei alone
are visible the fourth nucleus lies either in the plane above or
below, forming a tetrahedron, each nucleus situated at one of the

136 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

apices. In the case where four nuclei are visible (FIG. 25) no
tetrahedron is formed; the nuclei lying opposite each other form
a pair and one pair usually lies at a slightly higher plane than
the other. Where two nuclei alone are visible in a pollen mother-
cell this may be due to the fact that the four-nucleated pollen
mother-cell is so situated as to expose only two nuclei. It is
likewise possible, although not so common, that the two nuclei
are the results of cell division after the heterotypic division followed
by nuclear division. From such figures it is accordingly clear
that successive division or bipartition of the pollen mother-cell takes
place as described below.

In the late telophase of the second, as in the first division,
chromosome-like bodies appear on the spindle fibers and in the
cytoplasm. In Fic. 24 three nuclei appear in a cell with their
spindle fibers. One of the nuclei is intact while the other two
are cut through in sectioning.

On the spindle fibers three bodies appear like those seen in the
first division (see F1G. 23). In this figure in the complete nucleus
there are unquestionably ten more or less spherical chromosomes,
while in the preceding sections of the same cell ten chromosomes
likewise appear in the other nuclei. In a slightly older stage, as
shown in FIG. 25, of Drosera filiformis, two large bodies are seen
on one of the central spindles with a number of smaller ones
distributed through the cytoplasm. In another section of a late
telophase stage of the homoeotypic division shown in FIG. 35 I
found cytoplasmic bodies which stain faintly and were promiscu- °
ously scattered through the cytoplasm and on the spindle. In
practically all cases where chromosome-like bodies appear, ten
distinct chromosomes may also be clearly seen. What the sub-
sequent history of these bodies is after the second division I have
been unable to learn. It is quite clear that they do not form
extra nuclei or dwarf nuclei as shown by Rosenberg, Tischler,
Juel, Gates, and others. It is not wholly impossible, as held by
Juel and Tischler, that these bodies may be the forerunners of
abnormalities which eventually lead to the disintegration of the
pollen mother-cell, but I have been unable to prove this. The
formation of the normal pollen grains follows. The nuclei are
reconstructed as they are after the heterotypic division. The
central spindle fibers do not disappear but remain as prominent

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 137

as they were in the early anaphase stages. Radiating fibers
extending in all directions appear about each of the four nuclei.
Cell division.—It is well known now (Guignard, ’15) that the divi-
sion of the pollen mother-cell both in monocotyledons and dicoty-
ledons may be either by successive division or bipartition or by sim-
ultaneous division or quadripartition. In Drosera rotundifolia, D.
filiformis, and D. intermedia, both types of division were observed
‘as intimated above. While it may be said that the predominant
method is by quadripartition (FIGs. 36, 37), successive bipartition of
the pollen mother-cell also appears. Cell divisions may follow at
once in the heterotypic division. As mentioned above, the
central spindle apparently remains unchanged but a cell wall is
formed. The nuclei now divide again and this is followed by cell
division so that four serially arranged pollen cells are formed
(Fic. 38). For quadripartition no cell wall is formed after the
first nuclear division. The nuclei divide again and after recon-
struction in the presence of both central and radiating spindle
fibers cell walls are formed simultaneously, cutting the cytoplasm
into four approximately equal parts.
While successive stages of development of the cell wall through
a cell plate have been observed in the somatic divisions as men-
tioned above, no indication is found of the presence of a cell plate
in the divisions of the pollen germ cells. Farr (’16) finds that in
Nicotiana and certain other dicotyledons quadripartition is the
rule and that it is accomplished by furrow rather than a cell plate.
The mother-cell wall in these cases is markedly thickened and
fills the constriction furrow during the division. I have seen these
preparations and the appearances are different from that in Drosera.
Cannon (’?03) and Samuelsson (?14) hold that cell division of the
pollen mother-cell is brought about by the constriction of the
cytoplasm as in the division in animal cells. If furrows are
present in Drosera they must be extremely narrow like those
shown in the slime moulds by Harper (’00, ’14), which proceed
from the periphery to the center of the cytoplasm (FIGs. 36, 37, 39)-
As suggested above, certain pollen mother-cells disintegrate.
The process of disintegration is comparable to that described by
Tischler (’06) for Bryonia and Syringa hybrid pollen. After
completion of the homoeotypic division the reconstructed nuclei
lose their nuclear membranes and the nuclear content and cyto-

138 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

plasm soon appear to be stretched. The chromatin and nuclear
substances now dissolve and impart their staining properties to
the entire cell contents. This is followed by a complete disor-
ganization of the cell contents. The pollen grains may have
formed mature walls before their cytoplasmic content disinte-
grates so that a considerable number of empty pollen grains have
been found in Drosera longifolia, D. binata, D. rotundifolia, D.
intermedia, and D. filiformis. There is considerable danger of con-
fusing these disintegration stages with badly fixed or over-stained
cells.

The pollen grain—The pollen grains of the Droseraceae are
unlike those of most species of plants in that the four pollen
tetrads remain permanently united. While the fact is of common
knowledge no adequate figures of these tetrad grains have been
published. Drude (?91) figures the pollen grains of Drosera rotundt-
folia. He shows four pollen grains arranged in a tetrahedron and
the outer surface of each grain thickly covered with spines. Drude
also shows a number of tubules which arise from the angle formed
by two adjacent pollen grains in the tetrad. He holds that these
tubules are pollen tubes and are formed after the pollen reaches
the stigma. Only one or two of them are functional and grow
out to penetrate the style. Drude does not show the structure
of the pollen grain in section nor does he describe the origin or the
exact position of the tubules. Diels (?06) accepted these observa-
tions although he apparently never studied these tetrads himself.
Rosenberg (?99) has also studied the pollen grains of Drosera
rotundifolia. He also refers to these tubules as pollen tubes but
correctly observes that they are formed before the pollen is dis-
charged from the anther. He characterizes them later (’09) as
pollen tube anlage which appear in great numbers as a crown sur-
rounding the (base) external contact edges of the pollen grain.
Rosenberg gives a number of text figures of sections of pollen
grains; they are all inadequate and in some respects inaccurate.
He gives no description of the origin of the tubule, though it
appears from some of his figures that these tubules arise from the
apex of the tetrahedral pollen grain.

The material of Drosera longifolia sent to me by. Professor
John Davidson and of Drosera binata which I obtained at The New
York Botanical Garden was very favorable for the study of the

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 139

fully developed pollen tetrads. My studies were made on paraffin
sections and on tetrads mounted 72 foto in glycerine to which a
few drops of glacial acetic acid were added. The pollen grains in
all the species I studied are arranged most commonly in tetra-
hedral form as were the nuclei in each of the pollen mother-cells
just before cell division. Each tetrahedron of course shows three
of the grains in one plane, while the fourth is hidden by them.
All the contact walls of course intersect at an angle of 120°. Be-
tween each two adjacent pollen grains a double row of projecting
tubules may be seen, one row coming from each grain. These
have been described by Drude as young pollen tubes. In my
opinion they are to be regarded as highly specialized germ pores
as will be further discussed below. In another less common type
found in the Droseras the pollen grains are arranged in pairs; a
line through the center of one pair lying at right angles to a similar
line through the other pair, and in a different plane. This arrange-
ment of the grains is shown in Fic. 42. A similar arrangement
of the grains has been figured by Andrews (’05) for Epigaea repens
L. The rows of tubules are also present with the grains in this
arrangement. So far as I can find, this particular type of germ
pore is peculiar to the Droseras and it is certainly worthy of
more careful study than has yet been given to it.

Each surface of the four grains in a tetrahedron is triangular
with one side more or less convex, which forms the base of the
grain. The other three lateral faces are contact surfaces by which
the pollen grain is joined to its neighbor in the tetrad. The exine
of the external convex surface of each grain is thickly covered with
short, almost tubercular spines as shown by Rosenberg (709).
The tips of the spines are occasionally ellipsoidal or lance-shaped.
The exine of the contact walls of the grains is somewhat thinner
than that of the external surface. On the inner surfaces of the
contact walls are found the so-called ‘‘tubules’’ which constitute
as already noted the most peculiar characteristics of the pollen
grain of the Droseraceae. They arise at the time when the thicken-
ing of the wall is going on and constitute in effect a diverging series
of channels or tubules lying on the inner surface of each of the
three contact walls of a grain. As shown in TEXT-FIGURE I,
they take their origin near the inner angle of each contact wall,
that is, near the apex of the tetrahedral pollen grain, considering

140 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the outer curved surface as the base. These channels are separ-
ated from each other laterally (TEXT-FIGURE 2) by what are in
effect thick ridges on the inner surface of the contact wall of the
grain. Channels are thus formed which are roofed over against
the mass of the grain. There are approximately from 12 to 15 such
channels to each pollen grain. These so formed tubules are some-
ONG:
C7 Ne
y ie |

Fic. 1. Longitudinal section through the apex Fic. 2. Cross-section of a pollen
of a pollen grain, showing the origin of the grain with its spherical base removed,
tubules. showing a diverging series of tubules.

what flattened against the pollen grain, as shown by comparing
TEXT-FIGURES land 2. They are more or less club-shaped, tapering
slightly toward the apex of the pollen grain and expanding and
separating from each other at their exposed ends. The tubules
have a much thinner coat than the walls of the pollen grain and
in many instances exceedingly delicate spinules can be observed
on their surface. The structure of a pollen grain of the Droser-
aceae may be compared to some extent to that of an Arcella.
The pore in the flat surface of the Protozoan serves as an out-
let for the pseudopods. In the case of the pollen grain the pro-
toplasm streams out through what seems to be a pore (TEXT-
FIGURE 2) formed by the inner walls of the tubules and enters the
mouths of the twelve to fifteen channels as shown in a median
section of a pollen grain in FIG. 41.

The question as to the function of these tubules has not as yet
been fully determined by me. While Drude and Rosenberg believe
they are pollen tubes no adequate evidence has yet been offered.
It appears from observations of early stages that they are formed
at the time the walls of the pollen grain are thickened and lead
me to the belief that they are germ pores comparable to those
found in such families as the Ericaceae, GEnotheraceae, and others.

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA I4I

In the cross and median sections of the pollen grains studied
I have been able to make further studies on the chromosome
number in the nuclear divisions here. Nuclear divisions in the
pollen grains of Drosera obovata have been described and figured
by Rosenberg (’09) and my observations in general are in perfect
accord with his. The pollen grain nucleus divides and two
smaller cells are formed, as shown in Fic. 41. I have studied
these divisions very carefully in Drosera longifolia and find that
the first division of the nucleus results in two equal nuclei. One
of these divides again and two smaller nuclei are formed. Cell
division follows and the daughter cells lie embedded in the
cytoplasm of the pollen grain. While I have not been able
to count the chromosomes on the spindle in these divisions, the
nuclei of these small cells show prochromosomes. So far I have
been unable to count twenty prochromosomes as maintained by
Rosenberg for this species. In view of these observations it is
quite apparent, as observed above, that further work must be
done on this interesting species. It is hoped that cultivated
material now growing in our greenhouses as well as fresh field
material will be available during the coming summer, so that
the reduction divisions in the pollen mother-cells of Drosera longi-
folia can be studied and the two species, D. longifolia and D.
rotundifolia, can be crossed in an effort to obtain the so-called
wild hybrid D. obovata.

I wish to mention here my indebtedness to Professor John
Davidson for supplying me with material of Drosera longifolia
and for his kind interest in the progress of my work. I also wish
to thank Professor N. Wille for sending me his herbarium speci-
mens of the Norwegian Drosera longifolia and D. intermedia.
To Professor R. A. Harper I wish to extend my sincerest thanks
for his kindly criticisms and helpful suggestions.

SUMMARY

1. The somatic cell division is brought about by the formation
of a cell plate similar to that described by Strasburger, Went,
and Timberlake for Monocotyledons and Gymnosperms.

2. The chromosomes of the last premeiotic division form the
prochromosomes of the pollen mother-cells, of which there are
ten pairs distributed over the linin network on the periphery of

142 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the nucleus. Ten bivalent chromosomes may be counted in
diakinesis and in the equatorial plate stage.

3. During the late telophase in the first division chromosome-
like bodies appear in the cytoplasm and on the spindle of pollen
mother-cells. The chromosome-like bodies resemble in general
the belated chromosomes in size, shape, and structure but on
closer examination they are found to be more like extranuclear
nucleoles.

4. Similar bodies appear in the late telophase of the second
division. That these bodies are the same as those seen in the
first division is hardly possible, for no chromosome-like bodies
have been observed at any other stage than in the telophases of
the first and second divisions.

5. The fate of the chromosome-like bodies is undetermined.
It is possible that they become dissolved in the cytoplasm after
the completion of each division. Perhaps these bodies are the
forerunners of abnormalities which bring about the disintegration
of the cell. Sterile pollen grains appear.

5. Cell division of the pollen mother-cell is by bipartition or
successive division and quadripartition or simultaneous division.
In either case no cell plates have been observed. Cell division
may possibly take place by constriction as in the case of the
animal cells. The constriction furrows must be extremely narrow
in the species of Drosera, like those described in the slime moulds.

LITERATURE CITED

1905. Allen, C. E. Nuclear division in the pollen mother-cells of
Lilium canadense. Ann. Bot. 19: 189-258. pl. 6-9.

1905. Andrews, J. M. Die Anatomie von Epigaea repens L. Beih.
Bot. Centralbl. 191: 314-320. pl. 6-8.

1901. Beer, R. The supernumerary pollen-grains of Fuchsia. Ann.
Bot. 21: 305—307.

1912. Beer, R. Studies in spore development. II. On the structure
and division of the nuclei in the Compositae. Ann. Bot. 26:
705-726. pl. 66, 67.

1905. Berghs, J. La formation des chromosomes hétérotypiques dans
la sporogénése végétale. La Cellule 22: 141-160. pl. 1, 2.

1907. Britton, N. L. Manual of the flora of the Northern United
States and Canada.

1903. Cannon, W. A. Studies in plant hybrids. The spermatogenesis
of hybrid cotton. Bull. Torrey Club 30: 133-196. pl. 7-10.

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 143

IQII.

1909.

IQII.

1906.

1909.

I9IO.
1912.

1914.
1891.

IQIO.

1899.

1907.

1909.

IQII.

1914.

1909.

IQII.

Carruthers, D. Contributions to the cytology of Helvella crispa.
Ann. Bot. 25: 243-252. pl. 18, 19.

Darling, C. A. Sex in dioecious plants. Bull. Torrey Club 36:
177-199. pl. 12-14.

Davis, B. M. Cytological studies on Oenothera, II. A com-
parison of the reduction divisions of Oenothera Lamarckiana
and O. gigas. Ann. Bot. 25: 941-974. pl. 71-73.

Diels, L. Droseraceae. In Engler, A., Das Pflanzenreich eget
I-132.

Digby, L. Observations on ‘‘chromatin bodies” and their rela-
tion to the nucleolus in Galtonia candicans Decsne. Ann.
Bot. 23: 491-5302. pl. 3, 34.

Digby, L. The somatic, premeiotic and meiotic nuclear divisions
of Galtonia candicans. Ann. Bot. 24: 727-757. pl. 59-63.
Digby, L. The cytology of Primula kewensis and of related

Primula hybrids. Ann. Bot. 26: 357-388. pl. 41-44.

Digby, L. A critical study of the cytology of Crepis virens,
Archiv. Zellforsch. 12: 97-146. pl. 8-10.

Drude, O. Droseraceae. In Engler & Prantl, Die Naturlichen
Pflanzenfamilien. 37: 261-272.

Farmer, J.B., & Digby, L. On the cytological features exhibited
by certain varietal and hybrid ferns. Ann. Bot. 24: 191-212.
pl. 16-18.

Fullmer, E. L. The development of the microsporangia and
microspores of Hemerocallis fulva. Bot. Gaz. 28: 81-88.
pin zs 8

Gates, R. R. Pollen development in hybrids of Oenothera lata
x O. Lamarckiana and its relation to mutation. Bot. Gaz.
43: 81-116. pl. 2-4.

Gates, R. R. The behavior of the chromosomes in Oenothera
lata X O. gigas. Bot. Gaz. 48: 179-199. pl. 12-14.

Gates, R. R. Pollen formation in Oenothera gigas. Ann. Bot.
257: 909-940. pl. 67-70.

Gates, R. R., & Thomas, N. A cytological study of Oenothera
mut. lata and O. mut. semilata in relation to mutation. Quart.
Jour. Mic. Sci. 59: 523-571. pl. 35-37-

Geerts, J. M. Beitrage zur Kenntnis der Cytologie und der
partiellen Sterilitat von Oneothera Lamarckiana. Rec. Trav.
Bot. Néerland. 5: 93-206. pl. 5-22.

Geerts, J. M. Cytologische Untersuchungen einiger Bastarde
von Oenothera gigas. Ber. Deutsch. Bot. Ges. 29: 160-168.
pl. 8.

144

1905.

IQI5.
1900.
1914.
1848.

1861.

1897.

1900.
I9OI.

1908.

IQII.
1898.

1905.

1908.

1905.

1899.
1903.

1904.

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Gregory, R. P. The abortive development of the pollen in
certain sweet peas, Lathyrus odoratus. Proc. Cambridge Phil.
Soc. 13: 148-157. pl. 1, 2.

Guignard, M. Sur la formation du pollen. C. R. Acad. Sci.
Paris 160: 428-433.

Harper, R. A. Cell and nuclear division in Fuligo varians.
Bot. Gaz. 30: 217-251. pl. 14.

Harper, R. A. Cleavage in Didymium melanospermum (Pers.)
Macbr. Am. Jour. Bot. 1: 127-144. pl. 11, 12.

Hofmeister, W. Ueber die Entwickelung des Pollens. Bot.
Zeit. 6: 649-656. pl. 6.

Hofmeister, W. Neue Beitrage zur Kenntnis der Embryo-
bildung der Phanerogamen. Abh. Math.-Phys. Cl. K. Sachs.
Ges. Wiss. 5: 631-760. pl. 1-25.

Juel, H. O. Die Kernteilungen in den Pollenmutterzellen von
Hemerocallis fulua und die bei denselben auftretenden Un-
regelmiassigkeiten. Jahrb. Wiss. Bot. 30: 205-226. pl. 6-8.

Juel,H.O. Beitrage zur Kenntnis der Tetradentheilung. Jahrb.
Wiss. Bot. 35: 626-660. pl. 15, 16.

Koernicke, M. Ueber Ortsverinderung von Zellkernen. Sitz.
Ber. Niederrhein. Ges. Nat. u. Heilkunde zu Bonn, I-12.

Lary de Latour, E. de. Sur des particularités cytologiques du
développement des cellules-méres du pollen de |’ A gave attenuata.
C. R. Acad. Sci. Paris 146: 833-836.

Lawson, A. A. The phase of the nucleus known as synapsis.
Trans. Roy. Soc. Edinburgh 47: 591-604. pl. 1, 2.

Lyon, F. M. A contribution to the life history of Euphorbia
corollata. Bot. Gaz. 25: 418-426. pl. 22-24.

Martins Mano, T. Nucléole et chromosomes dans le méristéme
radiculaire de Solanum tuberosum et Phaseolus vulgaris. La
Cellule 22: 57-77. pl. 1-4.

Nichols, M. L. The development of the pollen of Sarracenia.
Bot. Gaz. 45: 31-37. pl. 5.

Overton, J. B. Ueber Reduktionsteilung in den Pollenmutter-
zellen einiger Dikotylen. Jahrb. Wiss. Bot. 42: 121-153.
pl. 6, 7.

Rosenberg, O. Physiologisch-cytologische Untersuchungen iiber
Drosera rotundifolia L. 1-126. pl. 1-2. Upsala.

Rosenberg, O. Das Verhalten der Chromosomen in einer
hybriden Pflanze. Ber. Deutsch. Bot. Ges. 21: 110-119. pl. 7.

Rosenberg, O. Ueber die Tetradenteilung eines Drosera-
Bastardes. Ber. Deutsch. Bot. Ges. 22: 47-53. pl. 4.

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA TA5

1909.

I9QT4.

1882.

}

Rosenberg, O. Cytologische und morphologische Studien an
Drosera longifolia X rotundifolia. K. Sv. Vet.-Akad. Hand.’
43: 3-63. pl. 1-4.

Samuelsson, G. Ueber die Pollenentwicklung von Anona und
Aristolochia und ihre systematische Bedeutung. Sv. Bot.
Tidskr..8: 181-189.

Strasburger, E. Ueber den Teilungsvorgang der Zellkerne und
des Verhaltniss der Kerntheilung zur Zelltheilung. Arch.
Micr. Anat. 21: 476-590. pl. 25-27.

Tangl, E. Die Kerne und Zelltheilungen bei der Bildung des
Pollen von Hemerocallis fulua. Denksch. K. Akad. Wiss.
Wien. Math.-Nat. KI. 45: 65-86. 1. 7-4.

Timberlake, H. G. The development and function of the cell
plate in higher plants. Bot. Gaz. 30: 73-99, 154-170. pl. 8, 9.

Tischler, G. Ueber die Entwicklung des Pollens und der Tape-
tenzellen bei Ribes Hybriden. Jahrb. Wiss. Bot. 42: 545-
579. pl. 15.

Tischler, G. Ueber die Entwicklung der Sexualorgane bei
einem sterilen Bryonia-Bastard. Ber. Deutsch. Bot. Ges. 24:
83-06. pl. 7.

Tischler, G. Zellstudien an sterilen Bastardpflanzen Arch.
Zellforsch. 1: 33-151.

Tischler, G. Untersuchungen iiber die Entwicklung des
Bananen-Pollens. Arch. Zellforsch. 5: 622-670. pl. 30, 31.

Wager, H. The nucleolus and nuclear division in the root apex
of Phaseolus. Ann. Bot. 18: 30-55. pl. 5.

Went, F. Beobachtungen iiber Kern- und Zelltheilung. Ber.
Deutsch. Bot. Ges. 5: 247-258. pl. 11.

West, C., & Lechmere, A. E. On the chromatin extrusion in
pollen mother-cells of Lilium candidum L. Ann. Bot. 29:
285-201. pl. 15.

Wille, N. Ueber die Entwicklungsgeschichte der Pollenkérner
der Angiospermen und das Wachstum der Membran durch
Intussusception. Krist. Vid. Selsk. Forh. 5: 1-71. pl. 1-3.

Wimmel, T. Zur Entwicklungsgeschichte des Pollens. Bot.
Zeit. 8: 225-235, 241-248, 265-270, 289-294, 313-321.

Zimmerman, A. Beitrage zur Morphologie und Physiologie der
Pflanzenzelle. Tiibingen.

Zimmerman, A. Ueber das Verhalten der Nucleolen wahrend
der Karyokinese. Bot. Centralbl. 57: 303-305.

146 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Explanation of plates

All the figures were drawn with the aid of a camera lucida from preparations stained
with Flemming’s triple stain. Leitz 1/16 objective and ocular 4 were used in making
the outlines but ocular 3 with the draw tube extended 15.2 cm. was used in drawing the
cytoplasmic and nuclear details.

PLATE 16
Drosera intermedia Hayne

Fic. 1. Resting stage of an immature pollen mother-cell, 2,666.

Fic. 2. Polar view of an equatorial plate stage of the premeiotic division of a
pollen mother-cell, X 2,700.

Fic. 3. Late anaphase of a somatic division, X 2,700.

Fic. 4. Similar stage, showing the chromosomes very distinctly in young pollen
mother-cell, 2,700.

Fic. 5. Beginning of a cell plate in the division of a vegetative cell, X 2,700.

Fic. 6. A slightly older stage, X 2,700.

Fic. 7. Cell plate in the premeiotic division of a pollen mother-cell, % 2,700.

Fic. 8. Completion of the cell plate in the division of a vegetative cell, X 2,700
Fic. 9. Diakinesis, showing bipartite and quadripartite chromosomes, X 2,666.
Fic. 10. Equatorial plate stage of the heterotypic division of a pollen mother-

cell, X 2,666.
Fic. 11. Polar view of an equatorial plate stage in the heterotypic division, X 2,666.
Fic. 12. Anaphase stage of a pollen mother-cell in the heterotypic division, X 2,666-
Fic. 13. Interkinesis, showing the chromosome-like bodies scattered in the cyto-
plasm and on the spindle fibers, X 2,666.
Fic. 14. Early anaphase stage of the homoeotypic division, X 2,666.

PLATE 17

Drosera rotundifolia (magnification, 2,666 diameters)
Fic. 15. Resting nucleus of a pollen mother-cell, showing paired prochromosomes.
Fic. 16. Leptoneme spireme, showing a single beaded structure.
Fic. 17. Early stage in synapsis.
Fic. 18.’ Same as Fig. 17, showing a somewhat later stage.
Fic. 19. Early stage in diakinesis.
Fic. 20. Equatorial plate stage of the first division.
Fic. 21. Polar view of an early anaphase stage.
Fic. 22. Late anaphase stage of the first division.
Fic. 23. Interkinesis, showing chromosome-like bodies in the cytoplasm and on

the spindle fibers.
Fic. 24. Reconstruction stage after the homoeotypic division, showing chromosome

like bodies on the spindle fibers.

Drosera filiformis
Fic. 25. Reconstruction stages after the homoeotypic division, showing chromo-

some-like bodies.
PLATE 18

Drosera filiformis
Fic. 26. Leptoneme spireme, showing the double thread-like chromatin bands,

2 125;
Fic. 27. Leptoneme spireme, showing the beaded structure of the chromatin bands,

X 2,125.

Meo. N. Y. Bot. GARDEN VoLuUME VI, PLATE 16

> I
6 aire a arte,
k d .
} . 2 at ee.
; tk had .
\3 A. yy a4 f g / ee
Wee * ard C ’
‘ So fej a S
Tak on ‘ re ]
\ r Tica ka /
eo \
e oy @
s ‘ ‘ iad f
i eg 4 2
¥ an} ey . e
& re | y j fa, o \
<a” Pa ey \
Lo at / ®
y | ca w* } 6
/ A | " d is
v 4 a >

a - >)
/ a
/ ae | ;
Been, sees
>
oo,
bay (| ie
Jon. ~.
|
5 %
: ) ho ee
<a c vy ; yt. iS oe — : ae
re ay ey ae c) f ohh aN
= ; i [> fT \
Yi = 3 J j ; v7 \

(
ay, a j
CA ie ' ;
6
j
a 10
ee 4
— \ ey
Ld . : 4
j

ne : hs aK Ay | | e

3 71

HELIOTYPE CO., BOSTON

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA

Meo. N. Y. Bor. GARDEN VOLUME VI, PLATE 17

B=
: 7
*
v '
j vA
° Jn, ~
Po ae
wis a4)
¥
15
; w 6G LF

HELIOTYPE CO., BOSTON

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA

a 2 foe ee , Ree ba a Coa |e © i:

Meo. N. Y. Bor. GARDEN VoLtumME VI, PLATE 158

HELIOTYPE CO., BCSTON

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA

«
, > a
- - - *
7 =
-
«h
as \ ’ ' 5
ry ~" é
7 ; a 7
7 > #5 : < “
- ° 7 . eS
‘wy Ys
7 ir © hee 4, ¥
7 i 7? OT
O
: '

e i -
“9 - = *)
'
LJ - “ -
a a y : a -
- *
: s 7 es
) = 7
: a =
P — : « ‘ ® =
- ?
= n i - , J
df @ ‘.
=- ot é s ' “
= 7 b :
- ‘ fu ,
» .
= ‘ ad r a ws .
= | . » ‘ b .
. s Ae
-
7, : 7
=
. - :
. - : .

Mem. N. Y, Bot. GARDEN VoLuME VI, PLATE 19

HELIOTYPE CO., BOSTON

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA

LEVINE: SOMATIC AND REDUCTION DIVISIONS IN DROSERA 147

Fic. 28. Later stage, showing fusion of thread-like chromatin bands has begun
25125;

Fic. 29. a. Sections of a cell, showing a pachyneme spireme. 0}. X 2,125.

Fic. 30. Early stages in the segmentation of the pachyneme spireme, X 2,125.

Fic. 31. Segmentation of the pachyneme spireme nearly completed, X 2,125.

Fic. 32. a, b, c. Sections of a cell in diakinesis, X 2,666.

Fic. 33. Equatorial plate stage, X 2,666.

PLATE 19
Drosera filiformis

Fic. 34. Interkinesis, showing the chromosome-like bodies in the cytoplasm and
on the spindle fibers, X 2,125.

Fic. 35. Homoeotypic division in the early telophase, showing faintly stained
chromatin-like bodies, X 2,125.

Fic. 36. Pollen mother-cell divided, showing three cells and their nuclei in one
plane.

Fic. 37. Pollen mother-cell divides, showing all four nuclei. A pair of opposite
nuclei lying in a different plane from that of the other.

Fic. 38. Pollen mother-cell divides, showing four serially arranged pollen cells.

Fic. 39. Pollen tetrad in process of exine formation.

Drosera longifolia
Fic. 40. a, b. Sections of an embryo sac mother-cell, X 2,700.
Fic. 41. Section of pollen grain, X 2,700.
Fic. 42. Pollen tetrad in which pollen grains are arranged in pairs, a row of germ
spores surrounding each pollen grain, X 2,700.

7
. | o
> .
9. ai }
- : ; 3 ;
« “a Rie "
td &.
re
: |
4 : a
eee ‘

ey th oe oF 7a" : t ‘/

SELF, CLOSE, AND CROSS FERTILIZATION OF
BEETS

Harry B. SHAW
Federal Horticultural Board, U. S. Department of Agriculture

(WITH PLATE 20)

The writer distinguishes three types of fertilization, namely,
(1) self fertilization, meaning that effected by pollen of the self-
same flower; (2) close fertilization, referring to that effected by
the pollen of one flower upon any other flower of the same plant;
(3) cross fertilization, that effected between the flowers of any
two plants.

The protandrous character of the beet flower was demonstrated
by Darwin and Rimpau. Although apparently the present
methods of beet breeding have largely been based on the evidence
of Darwin and Briem as to the susceptibility of the beet to close
fertilization, the published data of these writers are not conclusive
on this point. For the purpose of creating and continuing pure
lines of sugar beets it has been the practice to isolate individual
beets by inclosing each selected plant in a small tent of white
fabric during the blooming period. (PLATE 1.) In more recent
practice several plants are inclosed in each tent, cross pollination
taking place among the inclosed plants.

Samples of the fabric used by several well-known German beet-
seed growers were obtained. The most closely woven of these
is very similar to that used in the writer’s experiments. (FIG. 1, c.)
Under such tents, single beets showed a fertilization of about 23
per cent, on the average. A somewhat greater percentage of
fertilization has been obtained by European writers under their
isolation tents.

Although the mechanism and sequence of beet bloom appear
to be especially favorable for close fertilization, it became doubt-
ful to the writer whether beets really are susceptible to close
fertilization; it also became almost a matter of certainty that the

149

150 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

above-described isolation tents do not prevent cross pollination.
Separate flowering stems isolated with paper bags generally re-
mained completely sterile, though occasionally a few flowers pro-
duced seed. ‘Thrips can readily pass through the meshes of any of
the above-mentioned fabrics, carrying beet pollen with them. The

Fic. 1. Sketch of a single mesh, greatly enlarged, of three samples of fabric used
by German beet seed growers to isolate seed beets to prevent cross pollination. The
dot in each mesh represents a beet pollen grain enlarged to the same extent. (C) repre-
senis also the fabric used by the writer.

writer has recently shown that wind-borne pollen sifts through
the tops of tents made of LL sheeting, of 64 threads to the inch,
this being the most closely woven fabric used. It is much more
closely woven than most of the fabrics used by European beet
breeders. .

Apparently the only available method of isolating beets under
normal conditions is to plant individual mother beets so remote
from each other as to prevent cross pollination by wind or insects,
A wind varying from 15 to 30 miles an hour will carry beet pollen
over fields of alfalfa to a distance of 400 feet, but the writer was
unable to discover any pollen at twice that distance. To be safe
from cross pollination by insects a distance of probably two miles
is necessary. In early experiments to isolate beets by distance it
was not found possible to plant beets two miles away from each
other and from garden beets grown by farmers. However this
was possible at Jerome, Idaho, in 1913. In the early spring of
that year a seed beet was planted at each of eight farms separated
from each other by at least two miles, in a locality where it was

SHAW: FERTILIZATION OF BEETS I5I

known that no other beets were grown. The highest percentage
of seed produced among these plants was 2.29; several of the
plants remained entirely sterile, although otherwise their growth
was normal.

After ascertaining that beet pollen can be preserved for a
considerable time, experiments involving hand pollination and
isolation with paper bags were carried out to determine con-
clusively whether the protandrous character of the beet flower
might be overcome by separately preserving the pollen of indi-
vidual flowers, collected when the anthers dehisced, and applying
the pollen to the appropriate flowers when the respective stigmata
had become receptive. -This was done with several hundred
flowers on numerous beets. All flowers thus self-pollinated
remained sterile. |

In addition, various types of close pollination were made, the
work being distributed among many plants. For example: The
pollen taken from flowers on one spike was applied to the receptive
stigmata of other flowers on the same spike. Of these flowers
2.63 per cent were fertilized and produced seed; in addition, the
carpels of 5.23 per cent of the flowers enlarged without forming
seed.

The application of pollen from flowers on one spike to the
stigmata of flowers on another spike on the same stem resulted
in an average fertilization of 5.23 per cent, and a carpel stimu-
lation of 5.8 per cent.

The transfer of pollen from flowers of one stem to the stigmata
of flowers on another stem of the same plant resulted in the
fertilization of 8.54 per cent of those flowers and the carpel
stimulation of 3.47 per cent.

Per cent of | Per cent of carpels

fertilization stimulated
1. Self pollination: pollen to stigma of same flower... 0.00 0.00_
2. Close pollination: pollen of one flower to stigma
of another flower on same spike...,........... 2.63 5.26
3. Close pollination: similar to No. 2, but with
ietopahidteye Mts) ath iter eet pe TR A i a 2.70 1.43

4. Close pollination: pollen of flower on one spike

to stigma of flower on another spike of same

LASNT tT clove tic eRe G: Gie'o OIC soi tio Ree CREE ERAN ae ean 5.23 5.80
5. Close pollination: pollen of flower on one stem

to stigma of flower on another stem of same

Pia eee eRe et oe eco ea rckgaesea tae 8.54 3.47
6. Close pollination: of plants isolated by distance... 0.00 to 2.29
7. Croce. Polat OG Miner AS er. fa ala» slsiiicies elec ce ss 100.00 possible.

152 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

When pollination is effected between two beets, although of
the same progeny, the percentage of fertilization appears to be
limited only by the refinement of the technic. These results are
tabulated above.

No microscopic examination has yet been made to ascertain the
behavior of the pollen tubes under the various conditions men-
tioned. No explanation or hypothesis is ventured at this time
to account for the different responses observed on an individual
beet. It is probable that minute biochemical differences exist,
which increase in magnitude as the physical intimacy or relation-
ship decreases. Other experiments have shown that the various
buds on the crown of a seed beet behave as separate individuals,
and that each bud on one beet may assume a different morpho-
logical development from the others in response to modifications
in environmental factors.

Explanation of plate 20
A plat of seed beets in full bloom at the experiment station, Ogden, Utah, showing
isolation tents of various sizes. It was found that wind-borne pollen can sift through
these tents and cross-pollinate the protected seed beets.

HVIQ) ‘NaG90 ‘SINAL NOILWIOSI GNV SLaHda GAAS

Oc F 7Ic 5 g Ne
OZ ALWId ‘JA ANWNIOA Naduvy “Log “A "N ‘Wa]

PRESENT STATUS OF THE PROBLEM OF THE
EFFECT OF RADIUM RAYS ON PLANT LIFE*

C. STUART GAGER

Brooklyn Botanic Garden

The discovery of radioactivity during the last decade of the
nineteenth century at once raised the interesting question, not
“‘will it act as a stimulus to plant life,’’ but ‘‘in what manner, and
to what extent will it affect the various life functions?’’ Experi-
mental inquiry established conclusions that any physiologist might
have formulated a priori. As with any other form of energy to
which plants are normally adjusted—vz., heat, light, gravitation,
electricity, oxidation, and other chemical actions—radioactivity,
within certain limits of intensity, favorably affects any physio-
logical process, causing an acceleration of it up to a certain point—
the optimum; beyond that point the stimulus is too great, and
the attempts at response result in retarded or unregulated func-
tioning, disorganization, disease, and death.

In volume III of the Memoirs of The New York Botanical
Garden, ‘‘Effects of the rays of radium on plants,’’ published in
December, 1908, this was experimentally demonstrated for
practically all the processes of plant life—germination, growth,
respiration, irritability, cell-division, synthesis of carbohydrates,
fermentation, and others.

Since that publication, several workers—chiefly in Europe—
have, from time to time, issued papers of various length, on the
effects of radium-rays on plants; but a careful reading of nearly,
if not all, of the literature has failed to disclose any real addition
to our knowledge of the subject since 1908. Other plant material
has been used, and results have perhaps, in some cases, been
stated in more accurate quantitative terms; but the net results of
all investigations may still be accurately summed up by the
brief statement that sufficed in 1908, viz., The rays of radium

* Brooklyn Botanic Garden Contributions No. 15.

153

154 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

act as a stimulus to plants; up to an optimum point the response
is an acceleration of function, but beyond the optimum the
response is a depression of function, culminating under certain
conditions in complete arrest of physiological activity, or in the
death of the tissue or organism.

Among those who have contributed to the literature of this
subject since 1908, may be mentioned Crochetelle (1913), Doumer
(1912), Fabre (1910-11), Molisch (1912-13), Petit (1913), Petit
& Ancelin (1913), Stoklasa (1912-14), and Vacher (1913). It is
significent to note that in characteristic European fashion, prac-
tically all of the papers published on the continent contain no
reference to the Memoir of the New York Botanical Garden,
though in a few rare instances a short ‘“‘popular”’ paper by the
author of that Memoir is cited.

Results of chemical study of very considerable significance in
connection with the subject of photosynthesis, were presented by
Stoklasa, Sebor, and Zdobnicky, in 1911 and 1913. These experi-
ments! deal with the synthesis of sugars from CO, and nascent
hydrogen, in the presence of K.CO;, under the influence of radium
rays. Formaldehyde polymerized in the presence of potassium
carbonate is stated to result in the formation of reducing sugars.
A hexose and pentoses were positively noted, but no ketoses.
This work has not been confirmed by other investigators. Since
radioactivity is a constant and universal factor of plant environ-
ment the hypothesis that it may be concerned in the baffling
process of photosynthesis is, to say the least, very attractive,
and worthy of painstaking investigation. But the writer is
inclined to believe that radioactivity is not involved as a normal
factor in photosynthesis, even though it may, under certain con-
ditions, favor the artificial synthesis of carbohydrates.

In connection with experiments, now in progress, on the use
of radium-rays in medicine, and especially in the treatment of
cancer and tumors, it is of the utmost importance to keep in mind
that under certain conditions of exposure the malignant growth
may be accelerated rather than retarded; but experiments with
plants as well as with animals show that embryonic tissue is much
more sensitive than mature tissue to radium-rays, and therefore

1 Biochem. Zeitsch. 30: 433-456. 1911. Compt. Rend. Acad. Sci. Paris 156:
646-648. 1913.

GAGER: EFFECT OF RADIUM RAYS ON PLANT LIFE LS5

more easily killed. If cancerous tissue is of embryonic nature, as
seems not improbable, then it should be possible to treat it with
success by exposure to the rays of any radioactive substance,
if the proper strength of the radiation and the suitable conditions
of exposure are accurately ascertained; otherwise more harm than
good may result.

Among a rather large number of investigations on this subject
may be mentioned that of Wood and Prime,! as one of the more
recent. These investigators found that 155 mgm. of radium
bromide, screened with I mm. of aluminum or with 0.8 mm. of
brass, and only about 1.5 mm. distant from beating embryonal
heart-tissue, does not kill it in 3 hrs., and does not stop the growth
of connective tissue cells. The same exposure, however, does
prevent the growth of Jensen rat-sarcoma, and inhibits, but does
not wholly prevent, the growth of the Flexner rat-sarcoma.
These observations are rightly held by the authors to emphasize
the danger of generalizing from a limited number of experiments.

One of the members of the Pennsylvania Commission on the
Chestnut Blight consulted the writer some time ago on the probable
efficacy of a solution of some radium-salt injected into the circu-
lation of the tree. Recalling that the fungus causing the chestnut
blight is largely confined to the cambium-layer, and also recalling
that the cambium is embryonic tissue, it is obvious that the in-
jection into a tree of any radioactive substance in sufficient quan-
tity to kill the fungal hyphae would also kill the cambium. The
cure would be more fatal than the disease.

That a form of energy shown to be capable, under favorable
conditions, of doubling the rate of growth of plants, might have
great agricultural possibilities is a very alluring proposition, and
was early subjected to experimental test. An exhaustive review
of the literature is not essential here, but a few investigations
may be noted.

Studies by Fabre? indicate that the presence of radium bromide
in the soil retarded the germination and development of Linum
catharticum.

In 1912 Ewart*® using a radioactive mineral, known experi-

1 Proc. Soc. Exp. Biol. Med. 11: 140-142. 20 My 1914.

2 Compt. Rend. Soc. Biol. Paris 70: 419-420. IgII.
3 Jour. Dept. Agr. Victoria 10: 417-421.

156 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

mentally to accelerate the germination of cereals, found that
when it was applied ‘‘as a manure’”’ to wheat there is first a
stimulation, followed ‘‘on prolonged contact,’’ by an injurious
effect. Ewart’s conclusion was that the radioactive mineral
does not appear to have any direct agricultural value, at least so
far as wheat is concerned.

Stoklasa! exposed cultures of several nitrifying and denitrifying
bacteria in nutrient solutions to the emanation from pitchblend,
and from his results drew the inference that radioactivity exerts
a considerable influence upon the general circulation of nitrogen,
and is therefore important in connection with the fertility of the
soil.

Malpeaux? studied the effect of a material ‘‘said to be radioac-
tive,” on the growth of potatoes, sugar-beets, oats, turnips, and
rye. While the exposed plants were thought to be darker green
than the controls, and to have been slightly stimulated, the yields
were not appreciably greater than where an ordinary fertilizer
was used. An increase in the percentage of sugar in the beets
was thought to be due to the influence of the rays.

In the same year Truffant* studied the effect of growing various
legumes in soils containing radium bromide, but also rich in
nitrogenous and other mineral fertilizers. He reported that the
larger the content of the radioactive substance, the smaller was
the yield. Experiments with chrysanthemums grown in pots
led to the conclusion that radioactive minerals in the soil, both
soluble and insoluble, and especially the black oxide of uranium,
may produce favorable results, but that radioactive residues from
commercial factories may contain such deleterious substances as the
salts of barium and sulphuric acid in injurious amounts. Experi-
ments with spinach grown in the field gave no decisive results.

Studies by Rusby! of the effect on crops of a substance claimed
by the Standard Chemical Company, of Pittsburgh, Pa., to be
radioactive led him to the conclusion that the substance, applied
as a manure, caused a substantial increase in the crop yield of
potatoes, radishes, celery, beans, cucumbers, tomatoes, egg plant,
carrots, beets, spinach, peas, pumpkins, cabbage, squash, clover,

1 Compt. Rend. Acad. Sci. Paris 157: 879-882. 1913.

2 Vie Agr. et Rur. 3: 289-293. 1914.

3 Jardinage, May, 1914. Agr. News, Barbados 13: 215. 1914.

4 Jour. N. Y. Bot. Gard. 16; 1-23. Ja 1915.

GAGER: EFFECT OF RADIUM RAYS ON PLANT LIFE iS Wi

peppers, corn, muskmelons, and other vegetables. The radio-
active fertilizer was applied to four plots of 100 sq. ft. each in
amounts of 25, 50, 100, and 200 lbs. respectively. The author
concludes (p. 15) that, “The amount of radium required for the
greatest results differed with different crops. In five cases 200
Ibs. per 100 sq. ft. gave the best results, in eight cases 100 lbs.,

in five cases 50 lbs., and in eleven cases 25 lbs.’’ ‘‘Families of
plants,’ the author says, ‘showed the same varying suscepti-
bility.” Thus, plants producing underground crops, such as

turnips and radishes, gave results analogous to those given by
plants with aboveground crops, such as cauliflower, cabbage, and
mustard. This statement is of considerable interest in view of the
fact, disclosed by laboratory experiments, and recorded by several
investigators, that tissues with chlorophyll react to radium-rays
differently from tissues without chlorophyll.

Rusby states (p. 21) that, ‘The relative effects on the upper and
lower portions of a sloping plot have not been uniform. Of ten
rows of celery so planted, plants on the lower rows are nearly
twice as large as plants on the upper ones, and the transition is
gradual and nearly equable. <A possible explanation of this,”’
says the author, “‘is by assuming that in case of a hard rain, with
surface drainage, the emanations! in the water in the soil would
quickly diffuse through the surface water and be carried down-
ward.”’

In this possible explanation two facts are overlooked: 1. That
freshly fallen rain water is radioactive, and produces physio-
logical stimulation to plants, as was demonstrated by experi-
ments recorded in the Botanical Garden Memoir above cited. The
mere accumulation of this water in relatively larger quantities near
the lower portions of a slope might cause differential conditions
of radioactive energy, and therefore differential results.

2. The possibility that the differential results may be attributed
solely to the excessive moisture at the lower portions of a drained
slope. The plants involved were celery, and celery is well known
to thrive in trenches, where there is, of course, more moisture
than on a drained surface. The gradual transition in size is

1 There is only one emanation (a radioactive gas) given off by radium. The author

here doubtless means to refer to the ions (streams of which constitute the @ and # rays
of radioactive substances), as well as to the radioactive gas or emanation.

158 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

what one could expect under such conditions, regardless of the
presence of a radioactive substance in the soil. In discussing
his mutation experiments, deVries has called attention to the
necessity of extreme care in securing an equable distribution of
moisture, and to the fact that the common slight irregularities
in the surface of the soil in seed-pans may cause marked differences
in the rate of growth of seedlings. |

If the application of minute traces of radioactive substances
to the soil can produce an increase of yield, the fact would be of
very great scientific as well as economic importance, more especi-
ally if, as Rusby states (p. 21) ‘‘The beneficial effects continue
over successive crops, perhaps for many years,’’ while ‘‘The
largest amount required by any crop would cost less than the
increased market value of such crop the first year.’’ The author
well says (p. 21) that radium is not a plant food, and that the
necessity of fertilizer is but little decreased by its use. But
that “‘The fertility of unused ground will spontaneously increase
at a much greater rate when treated by radium,” is not self evi-
dent from any facts that have been obtained by observation or
experiment, though it ought not to be difficult to refute or to
confirm it experimentally.

‘But let us analyze the situation a little more thoroughly. The
second chapter of the Garden Memoir reviewed a large literature,
covering 149 titles, showing that radioactivity is normally a factor
of plant environment; that freshly fallen rain and snow, soil,
common rocks, soil-air, and, in fact, practically every kind and
form of matter is more or less radioactive. The magazine adver-
tisements of the radioactive compound employed by Rusby
recommend that one pound will fertilize 50 sq. ft. of soil. The
compound is claimed to contain 0.05—0.08 microgram (5 to 8 X 1075
gram) per pound. Now fifty square feet of ordinary top soil has
been found by experiment to contain approximately two mil-
lionths (5 & 107’) grams of radium. In other words the use of
the radioactive fertilizer according to the directions of its manu-
facturers would increase the radioactivity of the soil by only one
tenth of the normal amount.

Ross! has also called attention to the fact that ‘‘the radium
present, on an average, in an acre-foot of soil, is about 100 times

1U.S. Dept. Agr. Bull. 149: 13. 11 D 1914.

GAGER: EFFECT OF RADIUM RAYS ON PLANT LIFE 159

greater than is contained in the quantity of radioactive manure
commonly recommended for application to an acre.”’

Ramsay! has recently calculated that in order to double the
amount of radioactive gas (emanation) in the soil ‘‘one must use
about 75 milligrams of radium per acre at a cost of $7,500.” This
amount is somewhat more than the possible increase in value of
any crop per acre, however stimulated, yet a less amount of
emanation would quite certainly be too weak to produce any
appreciable physiological effect.

Hopkins and Sachs? carried on extensive and careful experi-
ments for two years with the radioactive fertilizer prepared by
the Standard Chemical Company, of Pittsburgh (the same
preparation that was used by Dean Rusby). Their final con-
clusion is as follows:

“Thus from the two years’ work we have six trustworthy
average results with corn, three ‘for’ and three ‘against’ radium,
and we have eighteen averages with soy beans, nine ‘for’ and
nine ‘against’ radium. In all of these trials the average vari-
ation from the checks is so slight and so evenly distributed ‘for’
and ‘against,’ as to lead only to the conclusion that radium
applied at a cost of $1, $10 or $100 per acre has produced no
effect upon the crop yields either the first or the second season.”’

The authors further point to the fact that to apply the radio-
active preparation to the soil in the amounts recommended by
Fabre would, at present market values, cost nearly $59,000 per
acre. To say the least, the results of various investigators seem
rather conflicting.

About two years ago the writer was presented with ten pounds
of a “‘radioactive”’ fertilizer, called B.D.R., by representatives of
the Radium Bank (Banque du Radium), of Paris, and was re-
quested to test its virtues for agriculture: Numerous experiments
were carried out, some closely following the directions given by
the representatives of the Radium Bank, and some according to
suggestions obtained from three years of experience in testing the
effects of radioactivity on plants. It is not necessary here to go
into details, but only to state that the net results of the tests were
absolutely negative.

1Science II. 42: 219. I915.
2 Science II. 41: 732-735. I915.

160 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Experiments by Lipman and Blair! with the same compound
gave entirely negative results; and Stevens? from experiments
also with the same compound, found that growth was accelerated
only when as much as 214 per cent of the compound was applied
to a soil. To employ it in agriculture in this proportion would
take about 25 tons to the acre, which would cost the farmer,
per acre, about $5,000.

In reviewing the literature, it is remarkable to note that in
a’most no instances was the so-called radioactive fertilizer tested
to see if it was really radioactive, and to what extent; nor was
it analyzed chemically to ascertain what elements of plant ‘‘food”’
it might contain. Without making these tests it is folly to
attempt to draw any inferences as to the value of radioactive
substances in practical agriculture.

From a large number of experiments on crop plants, Berthault,
Brétigniére, and Berthault® concluded that better results were
obtained by combining radioactive substances with standard
fertilizers. None of the results obtained by these authors were
considered as due to the known presence of certain chemical
compounds which stimulate plant growth; but all results were
attributed to radioactivity, notwithstanding the authors’ frank
statement that, when the compound they used was tested, not a
trace of radioactivity could be detected.

The evidence here briefly reviewed would seem to justify the
broad inference that, although radioactivity may act as a stimulus
to plant growth, our present knowledge of the cost of radium,
and of its physiological effects, affords little, if any, ground for
expectation that it possesses any value for practical agriculture.

1 New Jersey Agr. Exp. Sta. Bull. 269. My 29, 1914.

2 Stevens Indicator, April, 1914, p. 150.
*Vie Agr. et Rur. 2: 241. 1913.

ENDEMISM AS A CRITERION OF ANTIQUITY
AMONG PLANTS

EDMUND W. SINNOTT

Connecticut Agricultural College

Those species, genera, or families of plants which are restricted
in their distribution to a particular region, and which from this
circumstance are termed “endemic” in that region, have frequently
been regarded as constituting the most ancient element in its
flora. A discussion of the extent to which this characteristic of
endemism may be used as a safe criterion of antiquity, particularly
when we are dealing with plants belonging to different growth
forms, is the purpose of the present paper.

An ecological analysis of the endemic elements in the floras of
various regions throughout the world provides us with some sug-
gestive facts which bear on this problem, for such an analysis
shows that the important endemic types in the north temperate
zone are radically different from those in the south temperate zone.
The writer has compiled a list of the genera of dicotyledons which
have 95 per cent or more of their species confined to Canada, the
United States, and northern Mexico, and which may therefore
fairly be said to be ‘‘endemic’’ in temperate North America.
These genera comprise over 2,200 species, of which only 235, or
slightly over Io per cent, are trees or shrubs. In the non-endemic
portion of the flora of this region, on the contrary, approximately
25 per cent of the species are woody plants, over twice as large a
proportion as in the endemic. An analysis of the essentially
endemic genera of Europe and adjacent temperate Asia and
Africa reveals a similar preponderance of herbs here as compared
with the non-endemic types.

In the southern hemisphere, however, precisely the reverse is
true. In Australia, for example, 83 per cent (3,347 out of 4,024)
of the species of the endemic genera are trees or shrubs, but only
37 per cent (623 out of 1,687) of the species of the non-endemic

12 161

162 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

genera are plants of this sort. In New Zealand 65 per cent (206
species out of 315) of the endemic element is woody, but only
42 per cent of the species of the non-endemic element. In Pata-
gonia and Fuegia, trees and shrubs comprise 52 per cent (347 out
of 667) of the species of those genera which are practically con-
fined to this region and which may fairly be called ‘‘endemic”’
in it, as opposed to 13 per cent (120 out of 920) of the species of
the non-endemic genera. The same fact is observable in South
Africa, where 70 per cent (3,296 out of 4,686) of the species of
the ‘‘endemic’”’ genera are woody, but only 42 per cent (1,369
out of 3,298) of the species of the non-endemic types.

In the north temperate land area, therefore, the endemic
(presumably most ancient) element in the flora has a decidedly
higher proportion of herbs than does the non-endemic element,
whereas in the southern hemisphere, it has a decidedly higher
proportion of woody plants. Does this indicate that herbs are in
general a more ancient type of vegetation than trees and shrubs
in the former area but a less ancient one in the latter? Such a
conclusion is opposed to the evidence recently brought forward
from various botanical fields! in support of the view that the
herbaceous type has invariably been derived from an earlier vege-
tation which was prevailingly woody, and the writer believes that
the explanation of the preponderance of herbs in the endemic
flora of the north temperate zone lies not in the antiquity of this
growth type but rather in the high degree of rapidity with which
plants belonging to it may undergo evolutionary change.

We must first of all distinguish clearly between two main types
of endemic plants: on the one hand, the isolated and localized
survivors of once much more widely spread types, which we may
call ‘‘relict’? endemics; and on the other hand, those plants which
owe their endemism to the fact that they have never spread
beyond the actual region of their evolutionary origin, and which
may there be named “indigenous’’ endemics. A list of the
endemic genera of any large area, arranged according to natural
relationships, is usually easy to divide into these two categories,
for genera which stand well apart from the rest, without near
relatives, are doubtless isolated survivors of once much more

1 Sinnott, E. W., & Bailey, I. W. The origin and dispersal of herbaceous Angio-
sperms. Ann. Bot. 28: 547-600. O 1914.

SINNOTT: ENDEMISM AS A CRITERION OF ANTIQUITY 163

common forms; while those which occur in definite groups, all
the members of which are closely related to one another, evidently
represent locally developed types, each group of genera the
nucleus for a new subfamily.

An analysis of the genera essentially endemic in temperate
North America reveals the fact that practically all the woody
types occurring in it are apparently “‘relict’’ endemics. Carya,
Planera, Maclura, Asimina, Umbellularia, Sassafras, Dirca, Calyco-
carpum, Robinia, Ptelea, Nemopanthus, Ceanothus, Garrya, Sym-
phoricarpos and many other shrub and tree genera exist without
very near relatives in North America, and the conclusion that they
are representatives of a flora at one time much more widely
distributed is strikingly confirmed by fossil evidence, which -
shows that species of many of them flourished in Europe or
Asia during Cretaceous or Tertiary time. That most of these
forms are indeed relicts, and may therefore claim a relatively
high degree of antiquity, seems certain.

We have observed, however, that the great bulk of North
American endemic genera are herbaceous in habit. There are a
number of herbaceous genera, for the ,most part poor in species,
among the relict endemics; but it is well worthy of note that these
are the decided exceptions, for the great majority of endemic
herbaceous genera are not distributed thus scatteringly through
the various families but occur in definite groups the members of
which are closely related to one another. Examples of such
grouping are: Stanleya, Thelypodium, and their allies; Lesquerella
and its allies; and Leavenworthia and its allies among the Cruci-
ferae: Eriogonum and its allies among the Polygonaceae: Sarra-
cenia and Darlingtonia among the Sarraceniaceae: Heuchera and
its allies among the Saxifragaceae: Zizia and its allies among the
Umbelliferae: Pterospora and its allies among the Ericaceae:
Cryptanthe and its allies among the Borraginaceae: A gastache
and its allies among the Labiatae: Pentstemon and its allies;
and Castilleja, Orthocarpus, and their allies among the Scrophu-
lariaceae: Brickellia and its allies; Solidago, Bigelovia, and their
allies; Townsendia, Sericocarpus, and their allies; Silphiwm and
its allies; Rudbeckia and its allies; Madia, Hemizonia, and their
allies; Baeria, Eriophyllum, Hymenopappus and their allies;
Microserts, Krigia, and their allies and Lygodesmia, Troximon, and

164 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

their allies among the Compositae; and a great number of others.
There are over seventy of these groups among the Dicotyledons
alone. The only woody genera which display such a segregation
are Cercocarpus and its allies, which comprise the subfamily Cer-
cocarpeae of the Rosaceae, and number only a very few species.

A similar constitution of the endemic flora may be observed in
Europe where, centering in the Mediterranean region, there are
scores of endemic herbaceous genera almost all of which fall into
sharply marked groups of closely related forms. ‘This is par-
ticularly noticeable among the Cruciferae, Leguminosae, Um-
belliferae, and Compositae.

These two great arrays of what we have called ‘indigenous’
endemic genera in North America and Europe seem to have their
centers of dispersal in the western and southwestern United States
and northern Mexico on the one hand, and in the Mediterranean
region on the other. That they are confined almost entirely each
to its own side of the ocean; that both are composed of groups of
closely related genera, very many of which are rich in species;
and that each constitutes a dominant and successful element in
the flora of its own region, all suggest that such endemic types
have either actually had their origin, or have at least undergone
the greater part of their development and dispersal since a free
exchange of plants between Europe and North America was dis-
continued, presumably somewhere about the middle of the
Tertiary. Had they been as common and widespread before that
time as today, they would in all probability be represented now
on both sides of the Atlantic, as are so many genera.

We may feel justified in concluding, therefore, that the ‘“‘relict”’
and the ‘‘indigenous’’ endemics in the north temperate zone do
indeed differ considerably in the degree of their antiquity; the
former representing decidedly ancient types, which may be held
to correspond to the ancient endemic genera of other regions, but
the latter seeming to have arisen in much more recent times.
The significant fact in the whole matter is that, with very few
exceptions, the iudigenous endemics are composed entirely of
herbaceous forms. In this wholesale development of new generic
types, why should not trees and shrubs have taken the place which
their abundance as species and individuals would seem to warrant?
Why have not our local varieties and species of woody forms,

’

SINNOTT: ENDEMISM AS A CRITERION OF ANTIQUITY 165

which we believe to have arisen for the most part since the isola-
tion of America from Europe, been extended much further and
developed into new genera?

The explanation of the whole matter apparently lies in the fact
that herbs, because of the brevity of their life cycle, are subject
to much more rapid evolutionary change than are most woody
plants. Given an equal degree of mutability, a species which has
a hundred generations a century, as does an annual herb, will
accumulate changes much more quickly, and will thus become
altered in type much sooner, than will a species having only three
or four, as do many trees, or even fifteen or twenty, as do the
more rapidly maturing shrubs.

Other things being equal, therefore, the herbaceous element
in any flora is the one which is quickest to change and which is
always the first to show the effects of isolation by developing
local types. North America and Europe, which have not long
been separated from one another, will consequently show many
‘‘indigenous”’ endemic genera which are herbs, but few or none
which are trees or shrubs.

The fact that herbs are so rare among the endemic types of
the great land masses of the south temperate zone, as we noted
above, is excellent evidence that the herbaceous element in the
vegetation of these regions has but recently appeared. Had
herbs been a prominent part of the flora there as long as they have
in the north, it is hard to believe that they would not likewise
have given rise to an endemic element very numerous in genera
and species.

In any discussion of endemism and its usefulness in determining
the comparative antiquity of the various portions of a flora, one
should therefore make a clear distinction not only between “‘relict”’
endemics, which from their nature are among the older members
of the flora, and ‘‘indigenous’’ endemics, which may or may not
be so; but in addition, and more particularly, between endemic
woody plants and endemic herbs. The former, from the extreme
slowness with which they tend to become altered in type, may be
generally counted upon as the most ancient floral element. Herbs
are subject to such rapid evolutionary change that endemic types
developed among them cannot well be compared as to antiquity
with those appearing among trees or shrubs.

166 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

This great difference in the rapidity with which plants undergo
evolutionary development, depending on the growth type to
which they conform, is therefore a fundamental consideration in
any discussion of endemism.

SUMMARY

1. The endemic elements in the floras of the south temperate
zone are preponderantly woody; those of the north temperate zone,
preponderantly herbaceous.

2. A distinction should be drawn between ‘‘relict’’ endemics,
which are survivors of a once more widely spread flora and there-
fore of relatively high antiquity, and ‘“‘indigenous’”’ endemics, which
are of local development and therefore less ancient.

3. In the endemic floras of Europe and temperate North America
almost all tree and shrub genera are relicts. The great majority of
endemic herbaceous types, on the other hand, are apparently of in-
digenous origin and have presumably arisen or become widespread
since a free exchange of plants between Europe and America was
discontinued.

4. The predominance of herbs among indigenous endemic types
is explained as due to the great rapidity with which plants be-
longing to this growth form may undergo evolutionary develop-
ment, owing to the extreme brevity of their life cycle.

A BOTANICAL TRIP TO NORTH WALES IN JUNE

ARTHUR H. GRAVES

Connecticut College for Women

After a winter’s work in the botanical laboratory of the Royal
College of Science and Technology, London, I was glad to accept
an invitation to join the faculty and students of the department
ina trip to North Wales—a regular annual event in their curriculum.

Leaving London early, June 4, we arrived at Llanberis, Wales,
at about sundown, in the heart of the mountain region and the
end of our railroad journey. From Llanberis it was a stage drive
of about five miles to our hotel, most appropriately named the
Gorphwyspha—which is Welsh for House of Rest—situated at
the head of the pass leading down into the Llanberis valley.
On either side, steep, apparently barren mountains rose above us;
and from our inn we could see the highest of them all, the giant
Snowdon, rising to an altitude of 3,750 feet, overtopping a host
of smaller peaks. Compared with our Rockies, or even our South-
ern Appalachians and White Mountains, this is no great elevation,
and yet it must be remembered that the region is so close to the
sea that this height is practically all sheer ascent.

These Welsh mountains, with their bare, sharp peaks, narrow
ridges, and treeless slopes are most unlike our Southern Appa-
lachians with their rounded contours and forested slopes. One
could almost believe he were in the heart of the Alps if it were
not for the lack of perennial snows and glaciers.

Although the geology of the region has not been fully worked
out, its main features are evident. The whole region, originally
submerged, was then overlaid with a stratum of Ordovician lime-
stone, which was subsequently more or less altered by igneous
intrusions. At present most of the limestone has been either
eroded or mingled with lava, felstones, and dikes of greenstones.
Consequently we find rocks containing various proportions of
lime, while Cambrian shales and slates also occur at the lower
altitudes. In general, the acid igneous rocks support little plant

167

168 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

growth, while the areas containing limestone are well watered
and rich in vegetation.

Our excursions through this region covered a period of five days,
and under the guidance of our leader, Professor J. B. Farmer,
an Alpine climber of note, the plant collecting, interspersed with
mountain climbing, proved a most delightful combination.

Fic. 1. Some of the party in front of the inn, ready for a day’s work; Professor J.
B. Farmer at the center of the group.

Certainly the region is not one which an inexperienced botanist
would pick out for collecting. As the eye traverses the mountain
slopes, from their green valleys to their bleak, bare summits,
the utter lack of a tree flora lends a peculiarly barren aspect to the
vegetation (FIGS. 2 and 3). A closer inspection, however, gained
during our ascent of these very slopes, reveals the fact that this ap-
parent sterility does not extend to herbaceous plants. Especially is
this true if one happens to follow alead in which a fair proportion of
limestone is mingled. Here one may come upon a bright pink
carpet of Silene acaulis L. the moss campion, or the crimson
Saxifraga oppositifolia L.; or the polygonaceous Oxyria digyna
(L.) Hill, the mountain sorrel, and the yellow-flowered Sedum

GRAVES: A BOTANICAL TRIP TO NORTH WALES 169

roseum (L.) Scop., the roseroot, with its thick, odorous rootstocks,
may nod alluringly from some rocky cleft. If he is fortunate, the
climber may also find himself on a rocky shelf, where perhaps the
brilliant yellow English cowslip, Primula veris L. and the red
campion, Lychnis dioica L. await him with a blaze of glorious color.
He may find intermingled with them also, plants of the handsome
yellow globe-flower, Trollius europaeus L. These last three, how-

Fic. 2. View of Snowdon (the further sharp peak), and part of the Snowdon
range, showing the rugged character of the country.

ever, are not exclusively mountain species like the former. Thalic-
trum alpinum L., the mountain meadow rue, and the little white
Arenaria verna L., the vernal sandwort, are apt to occur nearby
in the grass of the high mountain meadows.

One large boulder, impregnated with a fair proportion of cal-
careous rock, deserves especial notice for the richness of plant
species it supported, and it was the more striking when compared
with the poverty of the greenstones and felstones in the immediate
neighborhood. On this rock, which we explored carefully, were
found Solidago Virgaurea L., the only goldenrod of which Britain
can boast (many of our species are cultivated in their gardens),

170 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Rubus saxatilis L., Antennaria dioica (L.) Gaertn., Pimpinella
Saxifraga L., a small species of Hieracium, Galium boreale L.,
Campanula rotundifolia L., Asplenium viride Huds., and A.
Trichomanes L., Silene acaulis L., and last, but perhaps the most
attractive, the beautiful creamy white Dryas octopetala L., the
mountain avens.

Other calcicolous species occurring here, many of them low-
land and woodland forms, or even maritime, are Oxalis Acetosella
L., Anemone nemorosa L. and Armeria vulgaris Willd. Of the
ferns, Allosorus crispus Bernh., Phegopteris polypodioides Fee,
P. Dryopteris (L.) Fée, Cystopteris fragilis (L.) Bernh., and
Hymenophyllum Wilsoni Hooker, are most abundant. The green
spleenwort, a very characteristic limestone plant, has already been
mentioned.

Although we have designated the region as treeless, it would be
hardly just to overlook an occasional specimen of Pyrus Aucuparia
(L.) Ehrh., the mountain ash. When sheltered in some rocky
nook, this grew to fair proportions, but in exposed locations was
quite stunted. The low juniper, Juniperus communis L. var.
montana Ait. too, on the lofty summits where it was abundant,
hugged the earth so closely as to appear little more than a carpet.
Salix herbacea L. also might be mentioned in this connection,
although no one could possibly call it a tree. We found it high up
on the summit of one of the peaks, perhaps 3,000 feet above
sea level. Not a sign of other vegetation was in sight, and care-
ful search was necessary to locate even this plant. Its rootstocks
held firmly down by flat stones, here and there, as if the hazard
was great, it raised itself only very slightly from its surroundings.
I collected one specimen about an inch high, bearing a staminate
catkin. On the particular summit in question, the winds were so
powerful that all the small flat stones with which the area was
covered had sunk into hollows made underneath them by the
gales. The whole summit, then, resembled a mosaic, so neatly
had the stones been thus fitted together.

Three plants which never occurred in limestone soils, but
formed a most exclusive society of their own, were Calluna vul-
garis (L.) Hull, Juniperus communis L. var. montana Ait., and
Vaccinium Myrtillus L. As far as I could see, no intruder ever
ventured into this community save Empetrum nigrum L. This

GRAVES: A BOTANICAL TRIP TO NORTH WALES WAL

combination held full sway near the tops of some of the peaks, or
above about 2,000 feet altitude. Higher up they too disappeared,
and the willow mentioned above was the sole member of the
phanerogamous vegetation.

Fic. 3. A lake in the Nant Ffrancon Valley.

A gorgeous sight awaited us in one of the mountain tarns, where
the cosmopolitan marsh marigold, Caltha palustris L., flourished
with all the lavish richness of golden yellow color which American
plant lovers know so well. In this same little lake, Jsoetes lacustris
L., Lobelia Dortmanna L., the latter of which I had collected the
year before in a Connecticut pond, Littorella lacustris L., and
Ranunculus Flammula L. grew in abundance. In other tarns,
Menyanthes trifoliata L. was found to be plentiful.

One of the rarest plants in Britain, Lloydia serotina (L.) Sweet,
was found high up in a narrow gorge. This is a small liliaceous
plant with morphological characters closely resembling those of
the tulip, but with a spreading perianth. It bears a single small
white flower, with the perianth segments showing longitudinal
reddish lines. Known in Britain only in some of the highest
Welsh mountains, it also inhabits the high mountain ranges of

My? MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Europe, the Caucasus region, and the alpine and arctic regions of
North America.

A frequent plant, worthy of mention, was the insectivorous
Pinguicula vulgaris L., also native with us from New Brunswick
to Quebec, to Minnesota and far north.

Everywhere in the grassy meadows and slopes at the foot of
the mountains Potentilla Tormentilla Sibth. was in evidence. It
occupies much the same place in the flora as our cinquefoils,
Potentilla canadensis L. and P. pumila Poir., and has a similar
appearance, but it has only four petals. In the boggy spots in
these meadows could be seen another insectivorous plant, also
native with us, Drosera rotundifolia L. With it often grew
Saxtfraga stellaris L. and Chrysosplenium oppositifolium L., the
latter under much the same conditions as our golden saxifrage,
Chrysosplenium americanum Schw.

I must not fail to add our own Myrica Gale L., which, also
indigenous there, was quite at home beside a meadow brook.

The mosses and liverworts are especially numerous, also the
algae, but fungi were scarce. Over thirty species of liverworts
were collected, and among the mosses was Oeditpodium Griffithianum
(Dicks.) Schwaegr. For a long time this was believed to be the
only plant peculiar to the British Isles, until it was discovered in
Norway, and it has since been found in Greenland and Alaska.

Perhaps one of the things which impressed me most through-
out the whole trip was the comparatively large number of in-
digenous plants which are also native in North America, for not
only those just mentioned, but many of the others named above
are reckoned among our indigenous plants. The generally ac-
cepted belief in a closer relation or a connection between Europe
and America in former geologic times was thus brought home to
me more forcibly than ever before; for what could be more con-
vincing evidence than to find such plants as the marsh marigold,
the low juniper, and the sweet gale, thrifty and important members
of the native flora!

NORTH AMERICAN SPECIES OF ALLODUS:

G.R., ORTON
Pennsylvania State College

INTRODUCTION

The genus Allodus Arth. of the Uredinales is a group of para-
sitic fungi having pleomorphic spore-forms and so far as is known
all species of the genus are autoecious.

The most conspicuous character of the genus is the frequent
close association of aecia and telia on the same plant parts and
the absence of distinct uredinia. These characters are identical
with those of Uromycopsis (Schrot.) Arth., a genus exactly parallel
with Allodus.

The failure to produce uredinia makes the aecial stage of
particular interest from the taxonomic and cytologic standpoint.
The cultural studies which have been made with species of this
genus are substantiated by the taxonomic studies.

The descriptive matter herein given is as brief as possible
without leaving out essentials. These descriptions together with
the analytic key should enable the collector and mycologist to
determine the species belonging to this genus, provided the speci-
mens bear more than one stage of the rust. The presence of
uredinia (2. e., uredinial sori, not necessarily urediniospores) at
once throws a rust out of this genus while the grouping of the telia
is quite distinct from that in the short cycle genus Dasyspora.

1 Contributions from the Department of Botany, Pennsylvania State College, No. 6.

This paper is the result of investigations started in the Botanical Laboratory of
the Purdue University Agricultural Experiment Station while the author was connected
with that institution. Uponhis removal to The Pennsylvania State College that part
of the Arthur Herbarium dealing with the subject matter was very generously loaned
for the continuation of this study. The writer is indebted to the officers and botanical
staffs of these institutions, who have so generously aided him.

To Dr. J. C. Arthur, who has aided the writer in many ways, especial acknowledg-
ment is made. To Dr. F. D. Kern the writer is greatly indebted for advice along
special lines. Acknowledgment is made also to Dr. H. D. House for the determination
of host plants of the genus Ipomoea.

173

174 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

COMPARISONS WITH OTHER RUST GENERA

The relationship of Allodus to other genera of the tribe Dicae-
omae is a most interesting subject. In many cases there are
species properly referred to Dicaeoma and Dasyspora which are
more closely related to species of Allodus than they are to any
species in their respective genera. A good example of this sort of
relationship is afforded by A. effusa on Viola lobata. ‘There is an
undescribed rust collected on Viola ocellata from the Rocky
Mountains, the teliospores of which are like the former species,
yet the rust has a full life cycle and is referred to the genus Dicae-
oma. Another undescribed rust collected at Dunsmuir, Cali-
fornia, on Viola lobata possesses only pycnia and telia and the
teliospores are almost identical with A. effusa. Another example
of the same kind of relationship, is found on Brodiaea, and
other examples undoubtedly exist. Here we have what to all
appearances seems to be three very closely related species or
forms of one species, yet each is placed in aseparate genus. To the
phanerogamic taxonomist such a separation is most confusing and
would be considered the height of inconsistency, for it fails to
show what a well co-ordinated classification should, namely—a
well-defined arrangement of species, families, etc., to show their
true relationship to each other and to other groups. It must be
conceded, however, that with the fungi, taxonomists are working
on a different basis from those who work with flowering plants
and animals. While in the fungi the term “‘species’’ may repre-
sent in a psychological way just as definite a thing as it does to
taxonomists of higher organisms, yet in reality the existing rela-
tionship is entirely different. Only among individuals where
interbreeding of distinct lines of descent exists, do true species
occur and therefore in the parasitic fungi the term species has an
entirely different interpretation. From this standpoint it would
seem to be unimportant whether a classification of such a group as
the rusts shows all real relationships so long as the result is a
clearer exposition of the nature and life histories of the organisms
dealt with.

So far as comparisons have been made there is no apparent
close relationship between species in the genera Allodus and
Bullaria. A careful comparative study of these two genera is
much needed.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS Bz

The genus Uromycopsis is exactly parallel with Allodus. They
differ in no way except in the number of cells in the teliospore.

Exceedingly complex questions arise as to the relation and inter-
relation of the eight genera in the tribe Dicaeomae. If the classi-
fication of the rusts proposed by Arthur has accomplished nothing
more, it has certainly opened up the whole subject from a new
standpoint and presented the rusts in such a manner that many
of these more difficult problems can be investigated more clearly
than ever before.

GENETIC RELATIONSHIP

Kern? has pointed out that it appears more probable to sup-
pose that the short cycle (Dasyspora) forms of rusts have been
evolved at one step from the long cycle (Dicaeoma) forms by
dropping out the intermediate spore forms. Olive® on the other
hand thinks that the long cycle forms have been evolved from the
short cycle forms by a process of amplification.

The writer’s work on Allodus and his study of this genus and
the other genera of the tribe Dicaeomae indicates that some
species of Allodus hold an intermediate position between Dicaeoma
and Dasyspora and that in some cases the transition between the
two extremes has been gradual rather than abrupt. It seems most
logical to accept the view that Allodus has been evolved from
autoecious species of Dicaeoma and that some species of Dasyspora
have in turn originated from species of Allodus. The remark-
able similarity of certain species‘of rusts in these three genera upon
the same or closely related hosts, indicate such a condition as
outlined above. Further prima facie evidence of such evolutionary
tendencies is found in certain species of Allodus where occasional
urediniospores occur in the telia. These urediniospores are in
every detail like the urediniospores of its correlated species of
Dicaeoma.

Bullaria appears to have developed from Dicaeoma in a manner
parallel with Allodus. It seems possible that certain meteoro-

1 Arthur, J. C. Eine auf die Struktur und Entwicklungsgeschichte begriindete
Klassifikation der Uredineen. Résult. Sci. Congr. Bot. Vienne 331-348. 1906.
2Kern, F. D. The genetic relationship of parasites. Am. Jour. Bot. 2: TEG—tate
1915.
3 Olive, E. W. Origin of heteroecism in the rusts. Phytopathology 1: 139-148.
IQII.

176 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

logical conditions are closely bound up with the evolution of
Allodus and Bullaria.

Host RELATIONSHIPS

A tabular presentation of the host orders and families of Allodus
is given below.

Class Order Family No. Species
Monocotyledoneae:........ Graminales;;.. kisser Gramineae... .......!. odes I
Bailiales: -\ 2.2. 6 eee PMISAEPAR. cg. oh a ote y cn to ae I
Liliaceae...... 5
Dicotyledoneae...........: Chenopodiales, .:..2.. 5: Ponkulacaceae. >. ...:.: 2% te. I
Ranales..4......35aeeeren Ranunculaceae............. 3
Berberidaceae. 2... . 62s a6 I
Papaverales.;45.ce eee SeMIGeKaes \ns)cKl os wis olesueed: I
Hy pericales... s.c-eeeeee: Witte] e221 5 Ae ons, I
Miyntalessc- eee eres Onagraceae: 0 ha. Peace I
Usmibellales: Staseena20 = AMAMMACEAL. .,. sig i ke 8
Primulalessasieereee <: : Erimulaceaes.. 5 «05 ska eke I
Gentianales ease. ... .Gentianaceae.« ..0i... sale I
Polemoniales»...........Convolvulaceae............ 6
Polemioniacede..... «23/5: tsa 2
Labiatae@sciekintes Ges oe 2
Solanaceaete so 4s ae ee I
Scrophulariaceae........... 2
Rubles eee ees. ss Rubiaceaey.s. ces ota 2
WValerianalesiim-e... 6. -: Valerianaceaesns... 22. ose I
Campanulales,.........-Ambfosiaeeae: os. I
Compositdeseenm see eee 5
Motalinumber. specieSa-amiacirreene oe eee 47

The most interesting point in connection with the host rela-
tionships is the absence of the order Rosales.

LIFE HISTORY

The genus Allodus was founded on Puccinia Podophylli Schw.,
a common rust in the United States east of the Mississippi River.
This species according to Olive! possesses perennial mycelia of
both gametophytic and sporophytic generations which inter-
mingle more or less constantly throughout the young host. Later,
independent sporophytic mycelia arising evidently from aecio-
spore infection, give rise to telia of the scattered type.

1Olive, E. W. The intermingling of perennial sporophytic and gametophytic
generations in Puccinia Podophylli, P. obtegens and Uromyces Glycyrrhizae. Ann. Myc
II: 297-311. 1913.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS D7,

This intermingling of mycelia of both generations is not known
definitely to occur in any other species of Allodus and so can
hardly be regarded as typical. Whether this species forms
secondary aecia has not been proved. What little cultural data
is at hand indicates that secondary aecia may or may not
occur in the genus and the taxonomic studies bear out this
statement.

The species in the genus appear to be quite variable in life
history. A. claytoniata has been cultured by Dr. F. D. Fromme
in the laboratory at Columbia University. His unpublished
results show that aeciospores from primary aecia, when sown
give rise to telia of the scattered type. The taxonomic studies
on this species corroborate his results.

Bubak! studied A. ambigua, a rust occurring in Galium A parine
in Europe and North America. He found that primary aecia
were followed by secondary aecia.

Treboux? has more recently checked up Bubak’s studies on
A. ambigua and found them to be correct. These results are in
accordance with those of Dietel? who cultured Uromyces Behenis
(DC.) Unger and Uromyces Scrophulariae (DC.) Fuckel, two species
to be referred to the genus Uromycopsis, which has the same life
cycle as Allodus. In both species in question he found that
secondary aecia followed primary aecia.

Although the number of cultures are limited they indicate
two distinct life histories. In one case primary aeciospores give
rise to telia of the scattered type. In the other case primary
aecia are followed by secondary aecia which in turn give rise to
telia formed around the secondary aecia and from the same
mycelium, or telia of the scattered type may be formed but
whether these last arise from primary or secondary aeciospore
infection is not known.

Other variations occur, such as evident perennial gametophytic
mycelium which appears to exist in A. consimilis, A. Douglasit,
A. Giliae, A. Chamaesarachae, A. intermixta, and A. Batesiana.

Cultural studies must be made to determine the nature of the

1 Bubak, Fr. O rezich, které cizopasi na nékterych Rubiaceich. Sitz.-ber. Bohm.
Ges. Wiss. 189878: 1-23. 1898. Reviewed in Zeitschr. Pfl.-Kr. 9: 116. 1899.

2 Treboux, 0. Ann. Mye.10: 305.) I912.

3 Dietel, P. Uber Rostpilze mit niederholter Aecidien-bildung. Flora 81: 394-404.
1895.

95 i,

178 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

sporophytic mycelium in these cases. It is probable that cases
similar to A. Podophylli will eventually be found.

Aecia (secondary) unaccompanied by pycnia were found in
twenty-four species and undoubtedly occur in other species, were
their history known. This brings up the question of the status
-of the aecium as a distinct unalterable phase in the life history
of certain rusts which lack uredinia.

It has generally been supposed that urediniospores were the
only repeating spores in the rusts. The occurrence of repeating
aeciospores in Allodus and Uromycopsis indicate that, while
morphologically they are aecidioid, functionally they may be
repeating spores.

All species of the genus are autoecious with one possible ex-
ception, A. graminella, a condition which may be said to be
typical of rusts with a shortened life cycle. The only known
exceptions are afforded by the genera Calyptospora and Gymno-
sporangium, both of which, with the single exception of Gymno-
sporangium nootkatense, lack uredinia also in their life cycle.

GENERIC DESCRIPTION

ALLODUS Arth. Résult. Sci. Congr. Bot. Vienne 345. 1906.

Cycle of development includes pycnia, aecia, and telia with
distinct alternating phases; autoecious. Pycnia and other sori
subepidermal.

Pycnia deep-seated, usually globoid or flask-shaped, with
ostiolar filaments.

Aecia erumpent, cupulate or cylindrical, of two sorts, primary
and secondary; the primary aecia sometimes giving rise to second-
ary aecia unaccompanied by pycnia; the secondary aecia fre-
quently followed by the telia. Peridium colorless, dehiscent by
apical rupture, the margin lacerate or erose, erect, spreading
or recurved. Aeciospores catenulate, globoid or ellipsoid, often
angular; the wall colorless or nearly so, verrucose.

Telia erumpent or long covered by the epidermis, arising either
around or from within the secondary aecia and later independently;
or arising at first independently from infection by aeciospores
from the primary aecia. ‘Teliospores free, pedicelled, two-celled;
the wall colored, firm, smooth or verrucosely sculptured.

Urediniospores rarely found in the telia.

Type species, Puccinia Podophylli Schw., on Podophyllum
peltatum L.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS

ANALYTICAL KEY
Teliospores spinulose. ie
Teliospores beset with long slender spines.
Teliospores coarsely tuberculate.
Teliospores less than 40 yu long.
Apex not more than 5 u thick.
Apex up to 7 p» thick.
Teliospores more than 40 yp long.
Apex not more than 5 yu thick.
Apex 6-12 yw thick.
Aeciospore wall 3 » or more thick.
Aeciospore wall less than 3 uw thick.

Aeciospore wall coarsely verrucose.

Aeciospore wall finely verrucose.

Aeciospores 16-22 by 19-26 yp.
Aeciospores 19-28 by 24-34 um.

Apex 12-19 p thick.
Teliospores finely verrucose.
Apex less than 3 » thick.
Teliospores not over 30 yu long.
Teliospores 30-40 yu long.
Ruptured epidermis conspicuous.

Telia rupturing epidermis to form a con-

spicuous ostiole.

Telia not rupturing epidermis as above.

Ruptured epidermis not conspicuous.
Apex 3-5 » thick.
Teliospore wall 1.5-2 p thick. .
Teliospores not constricted at septum.
Teliospores constricted at septum.

Teliospores conspicuously verrucose, especi-

ally at apex.

Teliospores very inconspicuously verrucose.

Teliospore wall 2.5-3.5 u thick.
Apex 5-8 yu thick.
Teliospore wall 1.5-2 uw thick.
Teliospore wall 2-3 p thick.
Pedicel normally placed, very short.
Pedicel placed at septum.
Pedicel normally placed, long.
Teliospore wall 3-4 u thick.
Teliospores striately verrucose.
Apex not thickened.
Teliospore wall 1-1.5 u thick.
Teliospore wall 2 » thick.
Teliospore wall 2-2.5 u thick.
Apex thickened up to 5 u.
Teliospore wall 3-3.5 u thick.
Apex 12-23 p thick.
Teliospores smooth.

42.

23.

20.
28. .

AS AS PS

AS AR PS

. Podophylli.

. asperior.
. rufescens.

. Carnegiana.
. opulenta.

. superflua,

. crassipes.

. megalospora.
. nocticolor.

. Chamaesarachae.

. intermixta,
. Erigeniae.
. lacerata,

. pagana,

. Calochorti.
. Palmert.
. effusa.

. claytoniata.

. Giliae.

. vertisepta.

. Musenit.

. Bouvardiae.

> subangulata.
. Moreniana.
. Jonesit,

. Lindrothii.
. msignis.

180 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Teliospore wall, I-1.5 u or less.
Teliospores small, less than 35 u long.
Apex rarely thickened up to 3 un. 47. A. subcircinata.
Apex 5-7 u thick. 44. A. tenuis.
Teliospores of medium size, averaging 35-45 u long.
Apex less than 74 thick, telia permanently

covered. 10. A. opposita.
Apex 6-10 u thick, telia tardily naked. 40. A. ambigua.
Apex 7-12 yu thick, telia rather early naked. 45. A. gnaphaliata.
Teliospores large, more than 45 pv long.
Apex 3-5 p thick. g. A. gigantispora.
Apex 5-8 u thick, 46. A. Desmanthodit.
Apex 7-16 pu thick. 43. A. Batesiana.

Teliospore wall 1.5—2.5 u thick.
Teliospores small, not usually more than 40 p long.
Apex 5-7 pv thick. 19. A. microica.
Apex 7-10 p thick. 13. A. consimilis.
Teliospores of medium size, not over 60 u long.
Apex not thickened.

Telia rather long covered by epidermis. 24. A. melanconioides.
Telia early naked. 25. A. Swertiae.

Apex 7-12 p thick. i
Teliospores slender, 15-21 » in width. 15. A. Ludwigiae.

Teliospores broader, up to 26 p in width.
Teliospore pedicel colorless or nearly so. 41. A. commutata.

Teliospore pedicel chestnut-brown. 32. A. Douglasit.
Teliospores large, 45-80 py long. 11. A. areolata.
Teliospore wall 3-5 yp thick.
Teliospore wall not over 3.5 « thick (on Gramineae). 1. A. graminella.

Teliospore wall up to 5 u thick.
Teliospore pedicel persistent, stout (on Am-

miaceae). 16. A. imperspicua.
Teliospore pedicel fugaceous, fragile (on La-
biateae), 34. A. mellifera.
Teliospore wall 5-7 u thick. 7. A. Dichelostemmae.

1. ALLODUS GRAMINELLA (Speg.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Aecidium graminellum Speg. Anal. Soc. Ci. Argent. 12: 77.
1881.
Puccinia graminella D. & H. Erythea 3: 80. 1895.

Aecia epiphyllous, scattered, often along the veins; aeciospores
20-25 by 20-30 uw; wall 3-4 yu thick.

Telia epiphyllous, scattered or crowded about the aecia, often
lineally confluent along the veins, early naked, ruptured epidermis
conspicuous, pulverulent; teliospores broadly ellipsoid, 22-28 by
35-55 vw, rounded at both ends; wall dark chestnut-brown, 3-5 u
thick, the apex 7-9 uw thick, smooth; pedicel colorless, rather stout,
up to 100 p long.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 181

On Gramineae:
Stipa eminens Cav.
TYPE LOCALITY: Buenos Aires, Argentina, on Stipa sp.
DISTRIBUTION: California; also in South America.
Exsiccati: Ell. & Ev. N. Am. Fungi 3350; Arth. & Holw. Ured.
29a; Ell. & Ev. Fungi Columb. S64.

2. Allodus pagana (Arth.) comb. nov.

Puccinia pagana Arth. Bull. Torrey Club 28: 372. Ig11.

Aecia unknown.

Telia amphigenous, scattered, oval, tardily naked, somewhat
pulverulent, ruptured epidermis disappearing at maturity; teli-
ospores oval to fusiform, 18-23 by 27-35 u, not constricted at
septum; wall cinnamon-brown, 1.5—2 u thick, thickened at apex,
up to 3 or 4.4, sometimes with pale papillae, very inconspicuously
verrucose; pedicel colorless, fragile, half the length of spore or less.
On Alliaceae:

[?] Allcwm reticulatum Don.
TYPE LOCALITY: Dead Lake, Pikes Peak, Colorado, on Allium
reticulatum.
DISTRIBUTION: Known only from type locality.
ExsiIccaTI: Clements, Crypt. Form. Colo. r4r.

The host collection in the Arthur Herbarium is fragmentary.
This species of rust is placed in Allodus chiefly because pycnia
and uredinia are lacking in the collection.

3. ALLoDUS CaLocHorRTI (Peck) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Puccinia Calochorti Peck, Bot. Gaz. 6: 228. I88I.
Puccinta anachoreta Ell. & Hark. Bull. Calif. Acad. Sci. 1: 14.

1884.

Puccinia Holwayi Diet. Hedwigia 32: 29. 1893.
Dicaeoma anachoreticum Kuntze, Rev. Gen. 3°: 467. 18098.
Dicaeoma Holwayi Kuntze, Rev. Gen. 3°: 469. 1898.

Aecia hypophyllous, in oval groups; aeciospores 16-23 by
19-26 u; wall 1.5-2 uw thick.

Telia chiefly hypophyllous, gregarious or scattered, soon naked,
pulverulent, dark chestnut-brown, ruptured epidermis conspicu-
ous; teliospores broadly ellipsoid, 19-29 by 29-42 yw; wall chestnut-
brown, 1.5-2.5 uw thick, thickened at apex 3-5 u, rather promi-
nently verrucose above; pedicel colorless, half the length of spore.

182 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Urediniospores occur rather frequently in the telia, being most
abundant on C. Gunnisonii and C. longebarbatus, broadly ellipsoid,
21-26 by 26-31 uw; wall light golden brown, 2—2.5 u thick, sparsely
and finely echinulate, the pores indistinct, 5 or 6, scattered.

On Alliaceae:

Allium sp. Calochortus albus Dougl., C. elegans Pursh, -C.
flavus Schult., C. Gunnisoni S. Wats., C. longebarbatus Dougl.,
C, nudus S.-Wats. and C. Nuttallu T. & G.

TYPE LOCALITY: Utah, on Calochortus Nutiallit.

DISTRIBUTION: Nebraska to Washington and Mexico.

ExsiccaTi: Ell. & Ev. Fungi Columb. 1953; Barth. N. Am.
Ured. 127, 533, 622; Clements, Crypt. Form. Colo. 549; Garrett,
Fungi Utah. go.

4. Allodus Moreniana (D. & T.) comb. nov.
Puccinia Moreniana Dudley & Thompson, Jour. Myc. 10: 53.

1904.

Aecia unknown.

Telia chiefly hypophyllous, scattered or sometimes grouped,
oval to oblong, tardily naked, ruptured epidermis conspicuous,
dark cinnamon-brown; teliospores oblong-elliptical, 20-24 by
33-50 uw, cells equal in size and shape; wall light cinnamon-brown,
uniformly about 2 y thick, inconspicuously marked with longi-
tudinal rows of fine papillae; pedicel colorless, about the length of
spore.

On Liliaceae:
Dipterostemon capitatus (Benth.) Rydb. (Brodiaea capitata
Benth.)
TyPE LOCALITY: Old Cement Mill, Searsville Lake, San Mateo
County, California, on Brodiaea capitata.
DISTRIBUTION: Known only from the type locality.
Note.—Puccinia nodosa E. & H. occurs in the type collection
of A. Moreniana. ‘The portion of this type in the Arthur herbar-
ium is fragmentary but it has the appearance of an Allodus.

5. Allodus Carnegiana (Arth.) comb. nov.
Puccinia Carnegiana Arth. Bull. Torrey Club 42: 587. 1915.
Aecia amphigenous, gregarious, in roundish or oval groups;
aeciospores 23-27 by 24-34 mu; wall 2-3 uw thick.
Telia amphigenous, scattered or arising about or within the
secondary aecia, oval or oblong, rupturing by a longitudinal

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 183

slit, tardily naked, blackish; teliospores ellipsoid or oblong,
27-34. by 42-58 uw; wall blackish when mature, 2.5-3.5 uw thick,
rarely thickened at apex up to 54, coarsely and prominently
tuberculate; pedicel colorless, up to the length of spore.

Urediniospores occurring rather commonly in the telia, broadly
‘ellipsoid, 27-35 by 32-424; wall golden yellow to cinnamon-
brown, about I—I.5 u thick, finely verrucose, echinulate, the pores
12-15.scattered.

On Liliaceae:
Dipterostemon pauciflorus (Torr.) Rydb. (Brodiaea capitata
pauciflora Torr.) |
TYPE LOCALITY: Tumamoc Hill, on grounds of the Desert Botanical
Laboratory of the Carnegie Institution of Washington, Tucson,
Arizona, on Dzipterostemon pauciflorus. (Altitude 2,700 ft.,
February 26, 1914, no. 5801.)
DISTRIBUTION: Known only from Tumamoc Hill, Tucson, Arizona.
Note.—Puccinia nodosa E. & H. a long cycle rust on Diptero-
stemon capitatus (Benth.) Rydb. from Southern California and
Puccinia tumamocensis Arthur, on Dzpterostemon ‘paucziflorus,
collected from the same locality and at the same time as Allodus
Carnegiana, possess teliospores remarkably like those of the last-
named species.

6. Allodus subangulata (Holw.) comb. nov.

Puccima subangulata Holw. N. Am. Ured. 1: 25. 1905.

Aecia amphigenous, crowded in small orbicular groups; aecio-
spores 19-25 by 24—30 wu; wall 2—2.5 uw thick.

Telia amphigenous, scattered, oblong, tardily naked, chestnut-
brown, ruptured epidermis conspicuous; teliospores broadly ellip-
soid, angular, 20-30 by 35-40 yu, cells often unequal in size and
shape; wall dark cinnamon-brown, uniformly I-1.5 yw thick, finely
rugose, with a few prominent longitudinal ridges; pedicel color-
less, rarely as long as the spore.

On Liliaceae:
Hookera pulchella Salisb. (Brodiaea congesta Smith, Dichelo-
stemma congestum Kunth.)
TYPE LOCALITY: State of Washington, on Brodiaea congesta.
DISTRIBUTION: Northwestern United States.

7. Allodus Dichelostemmae (D. & H.) comb. nov.

Puccinia Dichelostemmae Diet. & Holw. Erythea 3: 78. 1895.
Aecia not known.

184 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Telia amphigenous, scattered or sometimes confluent, oval to
linear, tardily naked, dark chestnut to chocolate-brown, ruptured
epidermis conspicuous; teliospores very broadly ellipsoid, 38-45
by 43-58 4; wall dark chestnut-brown, uniformly 5-7 uw thick,
smooth; pedicel colorless, usually deciduous, often laterally at-
tached, up to 100 yu long.

On Liliaceae:
Hookera pulchella Salisb. (Brodiaea congesta Smith, Dichelo-
stemma congestum Kunth.)
TYPE LocALity: Bingen, West Klickitat Co., Washington, on

Dichelostemma congestum.

DISTRIBUTION: Washington and Oregon.
ExsiccaTI: Barth. N. Am. Ured. 239, 1541.

Note.—A. subangulata frequently occurs together with A.

Dichelostemmae on the same host.

8. ALLODUS CLAYTONIATA (Schw.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Caeoma (Aecidium) claytoniatum Schw. Trans. Am. Phil. Soc. II.

4: 294. 1832.

Puccinia Mariae-Wilsont G. W. Clinton, Bull. Buffalo Soc. Nat.

Sin GOs (18732:

Dicaeoma claytoniatum Kuntze, Rev. Gen. 3°: 466. 1808.
Puccinia claytoniata Peck, Bull. N. Y. State Mus. 6: 226. 1899.

Aecia amphigenous, regularly scattered, often over large areas
and covering entire leaf and petiole; aeciospores 13-21 by 18-23 y;
wall 1-1.5 pw thick.

Telia chiefly hypophyllous, often thickly scattered, sometimes
confluent, small, roundish, tardily naked, cinnamon-brown, pul-
vinate, ruptured epidermis noticeable, teliospores elliptical to
terete, sometimes angular, 18-27 by 30-48 uw; wall light cinna-
mon-brown, 1.5-2 u thick, apex often thickened up to 7 by a
hyaline papilla, evenly and finely verrucose; pedicel colorless,
short.

On Portulacaceae:

Claytonia asarifolia Bong. (Montia asarifolia Howell), Clay-
tonia caroliniana Michx., Claytonia siberica L. (Montia siberica
Howell), and Claytonia virginica L.

TYPE LOCALITY: New York, on Claytonia virginica.
DIsTRIBUTION: New England to W. Virginia and the Pacific
Coast.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 185

ExsiccaTi: Ell. & Ev. Fungi Columb. 875; Shear, N. Y. Fungi
73, 131; Seym. & Earle, Econ. Fungi Suppl. B 27; Kellerm.
Ohio Fungi 22, 72; Garrett, Fungi Utah. 67; Sydow, Ured.
323, 1915, 1320, Barta. N. Am. Ured. 20, 133, 424, 425, 538, 833;
Ellis, N. Am. Fungi ror7, 1027; Rab. Fungi Eur. 2909; Roum.
Fungi Gall. 3414.

Note.—An undescribed Dasyspora on Claytonia megarrhiza from

Colorado has teliospores indistinguishable from those of A.

claytontata.

g. ALLODUS GIGANTISPORA (Bubak) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Puccinia gigantispora Bubak, Sitz.-ber. Bohm. Ges. Wiss. 1901:

G, \/190n:

Aecia hypophyllous, occasionally caulicolous, on yellowish or
reddish spots, roundish or elongated on veins; aeciospores 16-23
by 19-26 u; wall about 1.5 uw thick.

Telia amphigenous, gregarious, arising about the secondary
aecia or later scattered, small, long covered by the epidermis;
teliospores cylindrical or linear, obtuse or truncate above, nar-
rowed below, lower cell often twice the length of the upper, 13-19
by 45-87 wu; wall 1-1.5 w thick, smooth, or with one to three longi-
tudinal ridges, apex 3-12 u thick, usually darker; pedicel con-
colorous with lower part of spore, short.

On Ranunculaceae:
Anemone cylindrica A. Gray, A. globosa Nutt., and A. nar-

cisstflora L.

TypPE LocaLity: Livingston, Montana, on Anemone patens var.

Nuttalliana, error for A. globosa. (Seymour, September 6, 1884.)
DISTRIBUTION: Assiniboia to British Columbia and Colorado.
Exsiccati: Barth. Fungi Columb. 4058; Barth. N. Am. Ured.

632, 633.

Note.—This species is separated from Puccinia deBaryana
Thuem. by its lack of stroma surrounding the telia. Dasyspora
Anemones-virginianae (Schw.) Arth. is frequently found on the
same host with these two species and also with heteroecious aecia
belonging to Dicaeoma Clematidis (DC.) Arth.

10. Allodus opposita sp. nov.

Aecia seen of secondary form only, hypophyllous, gregarious
on discolored spots; small, cupulate; aeciospores subgloboid,
14-18 by 18-24 uw; wall 1-1.5 uw thick, finely verrucose.

186 MEMOIRS OF THE NEW YORK BOTANICAL ‘GARDEN

Telia chiefly epiphyllous, opposite the aecia, flat, spreading,
black, very long covered by the epidermis; teliospores cylindrical,
13-19 by 32-50, truncate or narrowed above; wall chestnut-
brown, I-1.5 » thick, smooth, apex thickened up to 7 u; pedicel
golden, short.

On Ranunculaceae:
Anemone globosa Nutt. .

TYPE LOCALITY: Sulphur Springs, Colorado, on Anemone globosa

(Clements, Crypt. Form. Colo. 563. July 19, 1907).
DISTRIBUTION: Known only from the type locality.
Exsiccati: Clements, Crypt. Form. Colo. 563.

The species differs from Puccinia japonica Diet. in having
larger aeciospores and thicker-walled peridial cells.

II. ALLODUS AREOLATA (D. & H.) Arth. Result. Sci. Congr. Bot.
Vienne 345. 1906

Puccinia areolata Diet. & Holw. Bot. Gaz. 19: 304. 1894.

Dicaeoma areolatum Kuntze, Rev. Gen. 3°: 467. 18098.

Aecia hypophyllous, in loose groups on yellowish spots, some-
times annular, circular or oval in outline; aeciospores 18-24 by
21-26 pw; wall about I yp thick, minutely verrucose.

Telia hypophyllous, gregarious on orbicular spots, small,
circular, often in annular groups, early naked, chocolate-brown,
ruptured epidermis noticeable; teliospores oblong to clavate, rarely
elliptical, 20-32 by 45-80 uw; wall chestnut-brown, 1.5-2 yu thick,
smooth or minutely rugose, the pores covered with a pale umbo
making the wall 7-9 uw thick; pedicel colorless, fragile, rarely as
long as spore.

Urediniospores occasionally found in the telia.

On Ranunculaceae:
Caltha biflora DC.
TyPE LOCALITY: Skamania Co., Washington, on Caltha biflora
(Suksdorf 318, August 12, 1886).
DISTRIBUTION: Known only from Washington.

12. ALLopUS PopopHYLLI (Schw.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Aecidium Podophylli Schw. Schr. Nat. Ges. Leipzig 1: 66. 1822.

Puccinia Podophylli Schw. Schr. Nat. Ges. Leipzig 1: 72. 1822.

Puccinia aculeata Link, in Willd. Sp. Pl. 6: 79. 1825.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 187

Puccinia Podophylli Link, in Willd. Sp. Pl. 6?: 79. 1825.
Puccinia aurea Spreng. Syst. Veg. 4: 568. 1827.
Caeoma (Aecidium) podophyllatum Schw. Trans. Am. Phil. Soc.

Lae 2035) hea.

Puccinia aculeata Schw. Trans. Am. Phil. Soc. II. 4: 296. 1832.
Dicaeoma Podophylli Kuntze, Rev. Gen. 3°: 470. 1898.

Aecia chiefly hypophyllous, closely gregarious on yellowish
spots, sometimes over large areas; aeciospores 18-24 by I9-29 nu;
wall about I uw thick, minutely verrucose.

Telia amphigenous and caulicolous, small, round, often gre-
garious in more or less orbicular areas on yellowish spots, tardily
naked, chocolate-brown; teliospores clavate to elliptical, 19-26
by 40-55 uw; wall chestnut-brown, uniformly 1.5—2 yw thick, spar-
ingly beset with spines about 7 uw long; pedicel golden yellow,
rarely half length of spore.

On Berberidaceae:
Podophyllum peltatum L.

TYPE LOCALITY: North Carolina, on Podophyllum |peltatum|.

DISTRIBUTION: New York to Minnesota and southward to the
Gulf of Mexico.

EXsICcATI: Rab.-Wint. Fungi Eur. 2977, 2912; Ellis, N. Am.
Fungi 257, 258; Seym. & Earle, Econ. Fungi 253; Thuem.
Myc. Univ. 547, 626;'Vesterg. Micr. Rar. Sel. 783; Roum.
Fungi Gall. 2429; Sydow, Ured. 76, 1318, 1378, 2127; Kellerm.
Ohio Fungi 73, 55; Barth. Fungi Columb. 2267, 3365, 3462,
3566, 3858, 3960, 4158, 4760; Barth. N. Am. Ured. 163, 256,
257, 403, 655, 959; Rav. Fungi Am. 482, 720.

13. Allodus consimilis (E. & E.) comb. nov.

Puccima consimilis Ell. & Ev. Jour. Myc. 6: 120. -1891.
Dicaeoma consimile Kuntze, Rev. Gen. 3*: 468. 18098.

Aecia hypophyllous, apparently arising from a perennial
mycelium, distributed rather evenly over the entire surface of
leaves; aeciospores 16-20 by 20-28 yu; wall about 1.5 u thick,
appearing smooth when wet.

Telia hypophyllous, arising from around or within the aecia,
circular, pulvinate; teliospores broadly ellipsoid, 16-22 by 31-37 u;
wall 1.5-2 4 thick, dark cinnamon-brown, smooth, apex 7-10 yu
thick, rounded; pedicel colorless, up to the length of spore, fuga-
cious.

188 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

On Cruciferae:

Sisymbrium lintfolium (Nutt.) T. & G.
TyPE LocALity: Helena, Montana, on Sisymbrium linifolium

(Kelsey, May 19, 1889, 54).

DISTRIBUTION: Known only from Helena, Montana.

Note.—The life history of this species is uncertain, as the evi-
dent perennial aecia are accompanied by pycnia and telia, making
a complicated condition. Culture work with this species must be
carried out before its life history can be known with certainty.
Most specimens referred to this species belong either to Puccinia
Holboellui (Hornem.) Rostr. or Aecidium monoicum Peck.

14. ALLODUS EFFUSA (D. & H.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Puccinia effusa Diet. & Holw. Erythea 3: 81. 1895.

Aecia amphigenous, in rather loose groups often scattered over
large portions of the leaf or along the petiole, more rarely annular,
circular; aeciospores 16-23 by 19-30; wall 1-1.5 u thick, very
inconspicuously verrucose.

Telia amphigenous, chiefly arising in or around the aecia, early
naked, dark chocolate-brown; teliospores broadly ellipsoid to
oblong, 20-30 by 32-51 uw; usually rounded at both ends; wall
chestnut to light chocolate-brown, 2.5-3 thick, moderately
verrucose above, nearly smooth below, the apex rarely thickened
up to 5 u; pedicel colorless, rarely the length of spore.

Urediniospores occurring sparingly in the telia, golden yellow,
21-26 by 27-35 uw, moderately echinulate; wall 3-3.5 » thick, the
pores 2, opposite, usually equatorial.

On Violaceae:
Viola lobata Benth. and V. praemorsa Doug}.
TYPE LocALity: Dunsmuir, California, on Viola lobata. (Holway,
May 30, 1894.)
DISTRIBUTION: Washington to Northern California.
EXsICccATI: Sydow, Ured. 2371; Barth. N. Am. Ured. 1438.
Note.—An undescribed Dicaeoma on Viola ocellata, and a Dasy-
spora, also undescribed, on Viola lobata from Dunsmuir, California,
are evidently correlated species. Dicaeoma Violae differs in
having thinner-walled and usually lighter-colored teliospores.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 189

15. Allodus Ludwigiae (E. & E.) comb. nov.

Aecidium Ludwigiae Ell. & Ev. Proc. Acad. Sci. Phil. 1893: 135.

1893.

Puccinia Nesaeae Ell. & Ev. Bull. Torrey Club 22: 363. 1895.

(Not Aecidium Nesaeae Ger. Bull. Torrey Club 4: 47. 1873.)
Dicaeoma Nesaeae Kuntze, Rev. Gen. 3°: 469. 1808.

Allodus Nesaeae Arth. Résult. Sci. Congr. Bot. Vienne 345. 1906.
Puccinia Ludwigiae Holway, N. Am. Ured. 1: 72. 1907. (Not

P. Ludwigiae Tepper, Bot. Centralb. 43:6. 1890.)

Aecia hypophyllous, in dense groups, often raised, rarely annu-
lar, on reddish spots, small, circular; aeciospores 13-19 by 15-
21 u; wall 1-1.5q thick, very minutely verrucose, appearing
smooth in water. |

Telia chiefly hypophyllous, inconspicuous, arising at first in
and later around the aecia, uncovered, compact, dark cinnamon-
brown; teliospores oblong to cylindrical or terete, 15-21 by
35-58 wu; wall cinnamon-brown, 1.5-2y thick, smooth, apex
7-12 w thick, slightly paler; pedicel slightly tinted, sometimes as
long as the spore.

On Onagraceae:

Ludwigia alternifolia L., L. glandulosa Walt., L. hirtella
Raf., L. polycarpaS. & P., L. sphaerocarpa Ell., L. virgata Michx.,
and L. palustris Ell.

TYPE LOCALITY: Ellendale, Sussex County, Delaware, on Ludwigia
sphaerocarpa (Commons, September 1, 1892).

DISTRIBUTION: Delaware to Iowa and to Florida and Louisiana.
Note.—The teliaare rarely collected; here described on L. poly-

carpa from Jowa and Missouri.

16. Allodus imperspicua (Syd.) comb. nov.

Puccimia imperspicua Sydow, Monog. Ured. 1: 361. 1902.

Aecia seen caulicolous only, gregarious, in oblong groups I-5
mm. long; aeciospores 19-23 by 21-27 uw; wall about fr uw thick.

Telia amphigenous, caulicolous, scattered or occasionally con-
fluent, roundish, early naked, pulvinate, chocolate-brown to
blackish; teliospores broadly ellipsoid, 24-34 by 34-51 uw; wall
light chocolate-brown, 3-5 u thick, the apex 7-10 p thick, smooth;
pedicel colorless, up to 100 yu long.

On Ammiaceae:
Arracacia multifida:S. Wats.

I9O MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

TyPE LOCALITY: Rio Hondo, Mexico, on Arracacia multifida
(Pringle, May 9, 1891).

DISTRIBUTION: South Central Mexico.

ExsiccaTI: Ell. & Ev. Fungi Columb. 2060.

17; ALLODUS JONESII (Peck) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Puccinia Jonesit Peck, Bot. Gaz. 6: 226. 1881.

Puccinia Cymoptert D. & H. Bot. Gaz. 18: 233. 1893.

Dicaeoma Cymoptert Kuntze, Rev. Gen. 3°: 468. 18098.

Dicaeoma Jones Kuntze, Rev. Gen. 3°: 469. 1898.

Aecidium Leptotaeniae Lindr. Medd. Stockh. Hogsk. Bot. Inst.

4)°Ss 1908;

Puccinia Traversiana Syd. Monog. Ured. 1: 889. 1904.

Aecia chiefly hypophyllous, caulicolous, gregarious in roundish
to oblong groups on yellowish spots; aeciospores 16-23 by 18-26 u;
wall 1-1.5 uw thick, finely verrucose.

Aecia amphigenous and caulicolous, scattered when foliicolous,
often confluent on the stems, tardily naked, chocolate-brown to
blackish; teliospores broadly ellipsoid to oblong, 18-24 by 29-43 u;
wall dark cinnamon to chestnut-brown, 2-2.5 u thick, usually
uniform, very minutely punctate to conspicuously verrucose, the
tubercles usually arranged in longitudinal striations; pedicel
colorless, deciduous, rarely the length of spore.

On Ammuaceae:

Aulospermum Betheli Osterh., A. purpureum (S. Wats.) C. &R.
(Cymopterus purpureus S. Wats.), Cogswellia foeniculacea (Nutt.)
C. & R. (Peucedanum foeniculaceum Nutt., Lomatium foenicu-
laceum C. & R.), C. Grayi C. & R. (Peucedanum Grayi C. & R.,
Lomatium Grayi C. & R.), C. macrocarpa (Nutt.) Jones (Peuce-
danum macrocarpum Nutt., Lomatium macrocarpum C. & R.),
C. nevadensis (S. Wats.) Jones (Peucedanum nevadensis S.
Wats.), C. orientalis (C. & R.) Jones (Peucedanum nudicaule
Nutt., Lomatium orientale C. & R.), C. platycarpa (Torr.)
Jones (Peucedanum simplex Nutt., Lomatium platycarpum
C. & R.), C. Suksdorfii (S. Wats.) Jones (Peucedanum Suks-
dorfit S. Wats., Lomatium Suksdorfi C. & R.), C. triternata
(Pursh) Jones (Peucedanum triternatum Nutt., Lomatium triter-
natum C. & R.), Cymopterus acaulis (Pursh) Rydb., C. Fendlert
A. Gray, Cynomarathrum Eastwood C. & R., Leptotaenia

ORTON: NORTH AMERICAN SPECIES OF ALLODUS IOI

Eatonii C. & R., L. multifida Nutt. (Ferula multifida A. Gray).
L. purpurea (S. Wats.) C. & R. (Ferula purpurea S. Wats.),
Musineon divaricatum (Pursh) C..& R., M. Hookeri (T. & G.)
Nutt. (M. trachyspermum Nutt.), Phellopterus montanus Nutt.
(Cymopterus montanus T. & G.), Pteryxia calcarea (Jones)
C. & R., and P. terebinthina (Hook.) C. & R. (Cymopterus
terebinthinus T. & G.).

TypE LocALIty: Utah, on Ferula multifida and Peucedanum
simplex (Jones, May and June).

DISTRIBUTION: Alberta to California and east to Kansas and
Nebraska.

ExsiccatTi: Carleton, Ured. Am. 3; Ell. & Ev. N. Am...Fungi
1448, 1856, 3581; Ell. & Ev. Fungi Columb. 1298, 1460, 19066,
1967, 2063; Barth. Fungi Columb. 3846; Sydow, Ured. 624,
1929, 1930; Clements, Crypt. Form. Colo. 567; Garrett, Fungi
Utah. 5,6, 7, 8; Barth. N. Am. Ured. 1055, 1056, 1146, 1236, 1550.
Note.—This species shows a wide variation in surface markings

of teliospores on different hosts. On Musineon divaricatum great

variation in this character is noticed on spores from one sorus.

18. Allodus Erigeniae sp. nov.

Aecia amphigenous, caulicolous, gregarious, or scattered, cupu-
late or short-cylindrical, 0.2-0.4 mm. in diameter; peridium color-
less, margin incurved; peridial cells rhomboidal in longitudinal
section, 21-23 by 29-45, the outer wall finely striate, 5-7 u
thick, the inner wall evenly and prominently lacerate-verrucose,
5-7 wu thick; aeciospores 16-21 by 19-264; wall I-1.5 u thick,
finely verrucose.

Telia chiefly hypophyllous, caulicolous, scattered, roundish to
oval, 0.3-1 mm. long, rather early naked, ruptured epidermis
conspicuous, pulverulent, dark cinnamon-brown; teliospores
broadly ellipsoid to oblong, 20-24 by 24-40 y, slightly constricted
at septum; wall cinnamon-brown, uniformly 1.5-2 » thick, finely
and inconspicuously verrucose; pedicel colorless, short, fragile.

On Ammiaceae:
Erigenia bulbosa (Michx.) Nutt.
Tyre LocALity: London, Ontario, on Erigenia bulbosa (Dearness,
May 1892).
DISTRIBUTION: Ontario to Ohio.
ExsiccaTi: Ellis, N. Am. Fungi rogo 0b.

192 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

19. Allodus microica (Ell.) comb. nov.

Puccinia microica Ellis, Jour. Myc. 7: 274. 1893.
Dicaeoma microicum Kuntze, Rev. Gen. 3°: 469. 1898.

Aecia hypophyllous, gregarious, in roundish or oval groups;
aeciospores. globoid, 14-19 w in diameter; wall 1-1.5 yu thick,
minutely verrucose.

Telia chiefly hypophyllous, caulicolous, crowded in and about
the aecia or arising independently, rupturing by an apical pore,
frequently in circular groups, cinnamon-brown; teliospores terete,
13-19 by 27-42 yu; wall light cinnamon-brown, about 2 yu thick,
smooth, the apical pores covered with hyaline papillae, making
the wall 5-7 u thick; pedicel colorless, rarely as long as the spore.
On Ammuaceae:

Deringa canadensis (L.) Kuntze (Cryptotaenta canadensis

Cis.) C2)!

TYPE LOCALITY: Garrett Park, Maryland, on Sanicula (?) error

for Deringa canadensis (Southworth, May 1890).

DISTRIBUTION: Maryland to Iowa.

Note.—Puccinia Cryptotaeniae Peck is probably a correlated

Dasyspora form. It has teliospores very similar to this species.

20. Allodus Lindrothii (Syd.) comb. nov.
Puccinia Lindrothii Sydow; Lindr. Acta. Soc. Faun. et Fl. Fenn.

22% B22), 1902.
Puccinia sphalerocondra Lindr. Acta. Soc. Faun. et Fl. Fenn.
22. 63. T902.

Aecia chiefly hypophyllous, caulicolous, gregarious, in roundish
or oblong groups; aeciospores 18-24 by 23-32; wall 1.5-2y
thick, finely verrucose.

Telia chiefly hypophyllous, caulicolous, scattered, rarely con-
fluent, rather early naked, ruptured epidermis conspicuous,
chocolate-brown; teliospores broadly ellipsoid to oblong, 18-26
by 29-42 u; wall chestnut-brown, 3-3.5 u thick, the apex rarely
thickened up to 5, evenly covered with longitudinal rows of
small tubercles; pedicel colorless, rarely as long as the spore.

On Ammiaceae:

Drudeophytum Hartwegii (A. Gray) C. & R. (Velaea Hart-
wegit C. & R., Arracacia Hartwegit S. Wats.), and Velaea arguta
(T. & G.) C. & R. (Deweya arguta T. & G.).

Type Loca.ity: Berkeley, California on Arracacia Hartwegit
(Blasdale, April 23 and May 3, 1894).

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 193

DistRIBUTION: Known only from California.
Exsiccati: Sydow, Ured. 877, 878; Rab.-Wint.-Paz. Fungi Eur.
4o22; Barth. N. Am. Ured. 349, 1250.

21. Allodus asperior (E. & E.) comb. nov.

Puccinia asperior Ell. & Ev. Bull. Washb. Lab. 1: 3. 1884.
Dicaeoma asperius Kuntze, Rev. Gen. 3°: 468. 1898.

Puccinia oregonensis Earle, Bull. N. Y. Bot. Gard. 273402),1902:
Allodus oregonensis Arth. Résult. Sci. Congr. Bot. Vienne 345.

1906.

Aecia hypophyllous, caulicolous, usually in large groups, often
covering the entire surface of leaflets and considerable portions
of the stems and petioles; aeciospores 18-22 by 20-29 u; wall 1.5-
2 p thick, finely verrucose.

Telia hypophyllous, caulicolous, scattered or in small groups,
often confluent, rather long covered by the epidermis, chocolate-
brown; teliospores broadly ellipsoid to oblong, 21-26 by 29-40 p;
wall chestnut-brown, 2.5-3.5 u thick, the apex rarely thickened
up to 5, coarsely and sparsely tuberculate; pedicel colorless,
rarely as long as the spore.

On Ammuaceae:
Leptotaenia dissecta Nutt. (Ferula dissoluta S. Wats.).

TypE LOCALITY: Klickitat Co., Washington, on Ferula dissoluta

(June, 1883).
DISTRIBUTION: Pacific Coast regions of the United States.
Exsiccati: Barth. N. Am. Ured. 1279.

Note-—Puccinia oregonensis was originally described as on
Sanicula. The host is Leptotaenia.

59. Allodus Musenii (E. & E.) comb. nov.

Puccinia Musenii Ell. & Ev. Bull. Torrey Club 27: 61. 1900.
Puccinia Seymourii Lindr. Med. Stockh. Hoégsk. Bot. Inst. 4°: 4.
1QOI.

Aecia unknown.

Telia amphigenous, caulicolous, scattered or confluent in large
groups, long covered by the epidermis, black; teliospores broadly
ellipsoid, 18-25 by 29-42 wu; wall dark chestnut to chocolate-brown,
2-3 wp thick, the apex 4-7 yu thick, conspicuously but finely verru-
cose, especially at apex; pedicel colorless, usually deciduous,
rarely 3 or 4 times the length of the spore.

194 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

On Ammiaceae:

Musineon |Musenium] tenuifolium Nutt., Pseudocymopterus
anisatus (A. Gray) C. & R., P. btpinnatus (S. Wats.) C. & R.,
and Oreoxts humilis Raf.

TYPE LOCALITY: Freezeout Hills, Wyoming, on Musineon tenui-
folium (Nelson, 4491, July 10, 1898).

DISTRIBUTION: Montana to Colorado and Nebraska.

ExsiccaTI: Clements, Crypt. Form. Colo. 139; Barth. N. Am.
Ured. 50.
Note.—The teliospore wall gelatinizes and the spores swell to

twice their normal size when heated in lactic acid.

23. Allodus lacerata sp. nov.

Aecia hypophyllous, caulicolous, gregarious on yellowish spots,
frequently in two rows when cn the veins; peridium white, margin
deeply and conspicuously lacerate; peridial cells rhombic to
rhomboidal in longitudinal section, 21-26 by 20-37 u, the outer
wall 4-5 u thick, smooth, the inner wall 5-7 u thick, lacerate-
verrucose; aeciospores 16-19 by 18-23 uw; wall 1-1.5 u thick, finely
verrucose.

Telia amphigenous, scattered, small, circular, early naked,
chestnut-brown, ruptured epidermis not conspicuous; teliospores
broadly ellipsoid, 23-26 by 32-37 u, constricted at septum; wall
dark cinnamon-brown, uniformly 1.5-2 4 thick, very minutely
verrucose; pedicel colorless, half the length of spore or less.

On Ammiuaceae:
Sanicula marilandica L.
TYPE LOCALITY: Palmer Lake, Colorado, on Sanicula marilandica
(Bethel, August I, 1903).
DISTRIBUTION: Colorado to Canada.
Note.—Puccinia Saniculae Grev. is a Dicaeoma correlated with
this species.

24. ALLODUS MELANCONIOIDES (E. & H.) Arth. Résult Sci. Congr.
Bot. Vienne 345. 1906

Puccinia melanconioides Ell. & Hark. Bull. Calif. Acad. Sci. 1: 27.
1884.

Dicaeoma melanconioides Kuntze, Rev. Gen. 3°: 469. 1898.
Aecia amphigenous, gregarious, annular; aeciospores 15-18 by

22-24 uw; wall about 1.5 uw thick, finely verrucose.
Telia amphigenous, scattered, rather long covered by the epi-

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 195

dermis; teliospores broadly ellipsoid 19-29 by 31-49 uw; wall light
chestnut-brown, uniformly 2-2.5 u thick, smooth; pedicel short,
colorless.
On Primulaceae:
Dodecatheon cruciatum Greene, Dodecatheon latifolium (Hook.)
Piper (D. Hendersonit A. Gray).
Typr LocaLity: Antioch, California, on Dodecatheon ‘‘ Meadia,”’
error for D. latifolium.
DISTRIBUTION: Pacific slope.
Exsiccati: Barth. N. Am. Ured. 155.
Note.—An undescribed correlated Dicaeoma occurs on the narrow-
leaved species of Dodecatheon.

25. Allodus Swertiae (Wint.) comb. nov.

Aecidium Swertiae Opiz,Seznam Rostlin 111. 1852. [Hyponym. ]
Puccinia Swertiae Wint. Rab.. Krypt. Fl. 1: 205. 1881.
Dicaeoma Swertiae Kuntze, Rev, Gen. 3°: 470. 1898.

Aecia amphigenous, gregarious; aeciospores 16-22 by 21-29 yu;
wall 1-1.5 » thick, light golden, finely verrucose, the pores rather
distinct, scattered.

Telia amphigenous, scattered, chestnut-brown, rather early
naked; teliospores broadly ellipsoid, 20-27 by 33-43 4; wall light
chestnut-brown, uniformly about 2 u thick, smooth; pedicel color-
less, short.

Urediniospores occasionally found in the telia of European
specimens.

On Gentianaceae:
Swertia perennis L., S. palustris A. Nels., and S. scopulina

Greene.

TypE LOCALITY: Bohemia on Swertva sp.
Distrinution: Rocky Mountain Region; also in Europe.
Exsiccati: Clements, Crypt. Form. Colo. 144.

26. Allodus opulenta (Speg.) comb. nov.

Puccinia opulenta Speg. Anal. Soc. Ci. Argent. 9: 170. 1880.
Aecidium Ipomoeae Speg. Anal. Soc. Ci. Argent. 9: 173. 1880.
Dicaeoma opulentum Kuntze, Rev. Gen. 3°: 469. 1898.

Aecia of primary form hypophyllous, sparsely gregarious, aecia
of secondary form amphigenous, gregarious, frequently along the
veins: aeciospores 18-24 by 21-31 mw; wall 3-3.5 thick, verrucose.

Telia amphigenous, usually surrounding the secondary aecia,

196 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

frequently confluent, forming large sori, light chocolate-brown,
rather early naked; teliospores ellipsoid, 24-35 by 45-70 uw, dark
chestnut-brown; wall 3.5-4 » thick, rather coarsely and sparsely
verrucose, the apex 10-13 uy thick, with a semi-hyaline umbo;
pedicel tinted next to the spore, up to 135 u long.
On Convolvulaceae:
Exogonitum arenarium Choisy (Ipomoea arenaria Steud.,
I. Steudeli Millsp.).
TyPE LocALITy: Boca del Riachuelo, Argentina, on Ipomoea
acuminata (Spegazzini, 1880).
DISTRIBUTION: West Indies; also in South America.
ExsiccaATI: Barth. N. Am. Ured. 429.
Note.—This species is readily separated from the other species
of Allodus occurring on Ipomoea by the uniformly thick-walled
aeciospores.

27. ALLODUS CRASSIPES (B. & C.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Puccinia crassipes Berk. & Curt. Grev. 3: 54. 1874.
Puccinia Ipomoeae Cooke; Lagerh. Tromso Mus. Aarsheft. 17: 61.
1895.
Dicaeoma crassipes Kuntze, Rev. Gen. 33: 468. 1898.
Dicaeoma Ipomoeae Kuntze, Rev. Gen. 3°: 469. 1898.

Aecia chiefly hypophyllous, often gregarious over the entire
leaf, aeciospores 16-22 by 19-26y; wall I-1.5 yu thick, finely
verrucose.

Telia amphigenous, surrounding the aecia, gregarious and often
confluent to form large sori, early naked, dark chocolate-brown;
teliospores broadly ellipsoid, 24-32 by 39-61 w; wall 3-4 u thick,
dark chestnut to chocolate-brown, moderately to sparsely and
rather coarsely verrucose, the apex 6-94 thick with a broad
semi-hyaline umbo; pedicel stout, tinted next to the spore, up to
100 u long.

On Convolvulaceae:

Ipomoea cathartica Poir. (I. acuminata (Vahl) R. & S.,
Phabartis cathartica Choisy), I. purga (Wender.) Hayne (J.
Jalapa Nutt. & Coxe), I. purpurea (L.) Roth, J. tiliacea (Willd.)
Choisy (I. fastigiata Sweet), I. trichocarpa Ell. (I. carolina
Pursh, J. commutata R. & S., I. caroliniana Pursh), J. triloba L.

TYPE LOCALITY: Santee Canal, South Carolina, on Ipomoea tricho-
carpa.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 197

DISTRIBUTION: Florida to Mexico and the West Indies; also
probably in South America.

ExsiccaTi: Barth. Fungi Columb. 2456; Rav. Fungi Am. 702.
Note—Aecidium Ipomoeae-panduranae Schw., and Aecidium

convolvulatum Link, are species of Albugo according to notes in

the Arthur Herbarium.

28. Allodus insignis (Holw.) comb. nov.
Puccinia insignis Holw. Ann. Myc. 2: 392. 1904.

Aecia of secondary form epiphyllous, occurring singly or in
groups of two or three on rather large yellow spots; aeciospores
not seen owing to lateness of collection.

Telia chiefly epiphyllous, in annular groups surrounding the
aecia, dark chocolate-brown, small, pulvinate, rupturing at apex
to form a characteristic ostiole; teliospores ellipsoid, 25-31 by
52-69 uw, usually narrowed above; wall dark chestnut to chocolate-
brown, 3-3.5 u thick, moderately and very inconspicuously verru-
cose-striate, the apex 12-23 u thick, narrowed to form a semi-
hyaline apiculus, slightly rugose at base; pedicel colorless, up to
85 uw long.

On Convolvulaceae:
Ipomoea Wolcottiana Rose.
TYPE LOCALITY: Cuernavaca, Mexico, on Ipomoea sp., now deter-

mined as I. Wolcottiana (Holway, September 25, 1895).
DISTRIBUTION: Known only from the type locality.

29. Allodus nocticolor (Holw.) comb. nov.
Puccinia nocticolor Holw. Ann. Myc. 2: 391. 1904.

Aecia chiefly hypophyllous, in groups over nearly the entire
leaf; aeciospores 19-24 by 24-29 uw; wall 2-3 y thick, thickened
above 5-8 yu, very finely verrucose.

Telia chiefly epiphyllous, in confluent groups opposite or about
the aecia, early naked, blackish; teliospores terete to fusiform,
26-32 by 51-71 pw; wall dark chocolate-brown, 3-4 u thick, coarsely
and sparsely verrucose, the apex 12-19 thick, nearly con-
colorous; pedicel up to 160 uw long, tinted close to the spore, fre-
quently swollen below to twice the average diameter.

On Convolvulaceae:

Ipomoea fistulosa Mart. and Ipomoea intrapilosa Rose.
TYPE LOCALITY: Cuernavaca, Mexico, on Ipomoea intrapilosa.
DISTRIBUTION: Mexico.

ExsiccaTI: Barth. N. Am. Ured. 1461.

198 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

30. Allodus superflua (Holw.) comb. nov.

Puccinia superflua Holw. Ann. Myc. 2: 392. 1904.

Aecia hypophyllous, the secondary form occurring singly or in
groups; aeciospores 16-19 by 21-26 yu; wall 2—2.5 uw thick, coarsely
verrucose.

Telia chiefly epiphyllous, scattered, singly or in small groups
over entire leaf, pulvinate, dark chocolate-brown, ruptured epi-
dermis conspicuous; teliospores 25-32 by 46-64 u, broadly ellip-
soid; wall 3.5-4 uw thick, dark chestnut to chocolate-brown, rather
coarsely and sparsely tuberculate, the apex 8-12 w thick, nearly
concolorous; pedicel light brown next to spore, up to 90 p long,
uniform.

On Convolvulaceae:
Ipomoea arborescens (H. & B.) G. Don.
TYPE LOCALITY: Iguala, State of Guerrero, Mexico on Ipomoea
murucoides, error for I. arborescens.
DISTRIBUTION: Known only from the type locality.

31. Allodus megalospora sp. nov.

Aecia chiefly hypophyllous, gregarious or occurring singly,
distributed over the entire leaf, opposite the telia; aeciospores
19-28 by 24-34 mu; wall I-2 pw thick, finely verrucose.

Telia chiefly epiphyllous, occurring singly or in groups, often
confluent to form large pulverulent sori, often on the veins opposite
the aecia, early naked, dark chocolate-brown, ruptured epidermis
soon becoming inconspicuous; teliospores ellipsoid, 24-33 by
48-71 w; wall 4-5 uw thick, chocolate-brown, coarsely tuberculate,
the apex 7—12 » thick, nearly concolorous; pedicel tinted next to
spore, stout, up to I15 p long.

On Convolvulaceae:
Ipomoea arborescens (H. & B.) Don, I. carolina L. (not J.

carolina Pursh), I. intrapilosa Rose, and I. murucoides R. & S.
TYPE LOCALITY: Oaxaca, Mexico, on Ipomoea murucoides.
DISTRIBUTION: Mexico and the West Indies.

ExsIccaTI: Sydow, Ured. 2036; Barth. N. Am. Ured. 429.

32. Allodus Douglasii (Ellis & Ev.) comb. nov.
Puccinia Douglasiit Ell. & Ev. Proc. Acad. Phil. 1893: 152. 1893.
Dicaeoma Douglasii Kuntze, Rev. Gen. 3°: 468. 1898.
Puccinia Richardsoni Sydow, Monog. Ured. 1: 317. 1902.
Aecia hypophyllous, covering the leaves, apparently from a
perennial mycelium; aeciospores 13-19 by 17-21 yw; wall I-1.5 4
thick, finely verrucose.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 199

Telia hypophyllous, usually in linear series along each side of
the midrib, circular, pulvinate, dark chestnut-brown; teliospores
ellipsoid to subpyriform, 16-24 by 35-60 uw; wall 2-2.5 u thick, light
chestnut-brown, smooth, the apex 8-12 p thick, concolorous; pedi-
cel concolorous, rather stout, up to 55 u long.

On Polemoniaceae:

_ Phlox alyssifolia Greene, P. depressa (A. Nels.) Rydb., P. dia-
pensioides Rydb., P. diffusa Hook., P. Douglasii Hook., and P.
subulata L.

TypE LOCALITY: Detroit, Utah, on Phlox Douglasit.
DISTRIBUTION: New Jersey to Washington, and New Mexico.
Exsiccati: Ell. & Ev. N. Am. Fungi 2991; Ell. & Ev. Fungi.

Columb. 1466; Barth. N. Am. Ured. 54.

33. Allodus Giliae (Peck) comb. nov.

Aecidium Giliae Peck, Bot. Gaz. 4: 230. 1879.

Puccinia plumbaria Peck, Bot. Gaz. 6: 238. 1881.

Puccinia Wilcoxiana Thuem. Myc. Univ. 2032, 1881.

Puccinia plumbaria phlogina Ellis, N. Am. Fungi 1044. 1883.
[Hyponym]

Aecidium Wilcoxianum Thuem. Myc. Univ. 2226. 1884. [Hy-
ponym|

Aecidium Cerastii Wint. Hedwigia 24: 179. 1885.

Aecidium Phlogis Peck; Arth. Bull. Iowa Agr. Coll. 1884: 167.
1885. [Hyponym]

Puccinia fragilis Tracy & Gall. Jour. Myc. 4:20. 1888.

Puccinia arabicola Ell. & Ev. Jour. Myc. 6: 119. 1891.

Aecidium Phlogis Ell. & Ev. Bull. Torrey Club 24: 284. 1897.

Puccinia Purpusii P. Henn. Hedwigia 37: 270. 1898.

Dicaeoma arabicola Kuntze, Rev. Gen. 3°: 467. 1898.

Dicaeoma fragile Kuntze, Rev. Gen. 33: 468. 1898.

Dicaeoma plumbarium \untze, Rev. Gen. 33: 470. 1898.

Allodus plumbaria Arthur, Résult. Sci. Congr. Bot. Vienne 345.

Puccinia giliicola P. Henn. Hedwigia 37: 270. 1898.
Aecia hypophyllous, usually covering the entire leaf, apparently

perennial; aeciospores 13-19 by 14-22 uy; wall about I p thick.
Telia chiefly hypophyllous, caulicolous, scattered, rather long

covered by the epidermis; teliospores broadly ellipsoid, 19-25 by

31-45 m; wall 2-2.5 4 thick, light chestnut-brown, finely and

closely verrucose, the apex 4-7 4 thick; pedicel colorless, short.

200 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

On Polemoniaceae:

Leptodactylon californicum H. & A. (Gilia californica Benth.),
L. Nuttall (A. Gray) Rydb. (Gilia Nuttallit A. Gray), Linanthus
ciliatus (Benth.) Greene (Gilia ciliata Benth.), Microsteris gracilis
(Dougl.) Greene (Collomia gracilis Dougl., Gilia gracilis Hook.),
M. humilis Greene, M. micrantha (Kell.) Greene, Phlox divaricata
L., P. longifolia Nutt., P. multiflora A. Nels., P. speciosa Pursh,
and P. Stansburyit (Torr.) Heller.

TYPE LOCALITY: Alta, Wasatch Mts., Utah, on Gila Nuttall
(Jones, August, alt. 8,000 ft.).

DISTRIBUTION: Ontario to Washington and south to California
and lowa.

ExsIccaTI: Ell. N. Am. Fungi zog4, 1432; Ell. & Ev. N. Am.
Fungi 1831, 3552; Ell. & Ev. Fungi Columb. 763, 1861, 1970;
Rab.-Wint. Fungi Eur. 3519; Roum. Fungi Gall. 3926, 5213;
Thuem. Myc. Univ. 2032, 2226; Sydow, Ured. 1212, 1527,
1030, 1037, 1038, 1030; Gametti Puno Uta 7) 2, 3, 37, see
Barth. Fungi Columb. 3857, 4761; Barth. N. Am. Ured. 162,
254, 255, 300, 1302; Rabebazg. Pune Eur, 2227.
Note.—Several of the species listed in the synonymy were

described on erroneously determined hosts.

34. ALLODUS MELLIFERA (D. & H.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Puccinia mellifera Diet. & Holw. Erythea 1: 25. 1893.

Aecia chiefly hypophyllous, singly or in small groups over a
large portion of leaves; aeciospores 19-22 by 22-31 yu; wall light
cinnamon-brown, 3-4 p thick, often appearing thicker, very finely
verrucose, the pores visible, scattered.

Telia amphigenous, caulicolous, scattered, early naked; telio-
spores broadly ellipsoid to obovoid, 25-31 by 40-47 uw; wall 3-5 pu
thick, chestnut-brown, smooth, the apex 7—9 u thick, concolorous;
pedicel colorless, fragile, up to 110 uw long.

On Labiatae:
Audibertia grandiflora Benth. (Salvia spathacea Greene),

A. incana Benth., and A. stachyoides Benth. (Salvia mellifera

Greene).

TYPE LOCALITY: Pasadena, California, on Salvia mellifera.
DISTRIBUTION: California to Nevada and Mexico.
EXsICCATI: Barth. N. Am. Ured. 457.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 201

35. ALLODUS VERTISEPTA (Tracy & Gall.) Arth. Résult. Sci. Congr.
Bot. Vienne 345. 1906

Puccinia vertisepta Tracy & Gall. Jour. Myc. 4: 21. 1888.
Diorchidium Tracyt De-Toni, in Sacc. Syll. Fung. 7: 736. 1888.

Aecia chiefly hypophyllous, gregarious on circular, discolored
spots; aeciospores broadly ellipsoid to pyriform; 17—20 by 28—40 yu;
wall 2-2.5 uw thick, rather prominently and moderately verrucose,
thickened at apex and base about equally, 5-9 u, golden.

Telia chiefly epiphyllous, scattered, early naked, ruptured
epidermis not conspicuous; teliospores subgloboid when seen with
both cells in view, broadly ellipsoid with only one cell in view;
wall dark chestnut to chocolate-brown, 2.5-3 4 thick, finely
verrucose, the apex 6-7 yu thick, hyaline at the tip; pedicel colorless,
attached at septum, up to 50 u long.

On Labiatae:

Salvia ballotaeflora Benth. and S. Sessez Benth.
TYPE LOCALITY: New Mexico on Salvia ballotaeflora.
DISTRIBUTION: New Mexico to Mexico.

ExsiccaTi: Barth. N. Am. Ured. 275, 875.

Note.—The so-called uredo are really aecia, according to a note
in the Arthur Herbarium by Holway, who has examined the
original specimen at the Mo. Bot. Garden.

36. ALLODUS CHAMAESARACHAE (Syd.) Arth. Result. Sci. Congr.
Bot. Vienne 345. 1906
Puccima Chamaesarachae Sydow, Monog. Ured. 1: 263. 1902.

Aecia hypophyllous, gregarious, covering nearly the entire
surface of leaves and dwarfing the plants; aeciospores 16-19 by
20-25 mw; wall 1.5-2 uw thick, finely verrucose.

Telia chiefly hypophyllous, within or among the secondary
aecia, sometimes confluent; teliospores broadly ellipsoid, 17-20
by 25-31 »; wall about 2 wu thick, light chestnut-brown, very finely
verrucose, the apex very slightly thickened, about 3 4; pedicel
colorless, short.

On Solanaceae:
Chamaesaracha nana A. Gray.
TYPE LOCALITY: California, on Chamaesaracha nana.
DISTRIBUTION: California and Nevada.
ExsiccaTi: Ellis, N. Am. Fungi 1476; Barth. Fungi Columb.

38540; Barth. N. Am. Ured. 229.

Note.—All collections from Truckee are from California; not
from Nevada as the data on packets appear to show.

202 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

37. ALLODUS PALMERI (D. & H.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Puccinia Palmeri Diet. & Holw. Erythea 7:98. 1899.

Aecia chiefly hypophyllous, scattered or in annular groups;
aeciospores 17-20 by 19-29 yu; wall 1.5-2 pw thick, golden.

Telia amphigenous, scattered among the secondary aecia, pul-
vinate, ruptured epidermis conspicuous; teliospores broadly ellip-
soid, 17-25 by 31-43 uw; wall 1.5—2 w thick, dark cinnamon-brown,
minutely verrucose, appearing smooth when wet, the apex 3-5 yu
thick; pedicel light golden, short.

On Scrophulariaceae:

Pentstemon chionophilus Greene, P. confertus Dougl., P.
Harbouru A. Gray, P. Menziesit Hook., P. Newberryi A. Gray,
P. ovatus Dougl., P. pinetorum Piper, and P. humilis Nutt.

Type Locality: Lake Tahoe, California, on Pentstemon confertus.
DISTRIBUTION: Washington to Colorado and Nevada.
ExsiccaTi: Barth. N. Am. Ured. 1463.

38. ALLODUS RUFESCENS (D. & H.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Puccinia rufescens Diet. & Holw. Bot. Gaz. 18: 253. 1893.
Dicaeoma rufescens Kuntze, Rev. Gen. 3°: 470. 1898.
Aecia amphigenous, singly or in groups, scattered over entire
leaf; aeciospores 17-23 by 20-29 uw; wall 1-1.5 uw thick, yellow.
Telia amphigenous, occurring around and among the secondary
aecia, rather large, ruptured epidermis not conspicuous; telio-
spores broadly ellipsoid, 19-26 by 29-42y4; wall 2-34 thick,
light cinnamon-brown, coarsely verrucose, the apex thickened
up to 7 u; pedicel colorless, short.
On Scrophulariaceae:
Pedicularis canadensis L., P. centranthera A. Gray, and P.
semtbarbatus A. Gray.
TypE Loca.Lity: King’s River Canon, California, on Pedicularis
semtbarbatus (Holway, July 15, 1892).
DISTRIBUTION: Colorado to California.
ExsiccaTi: Sydow, Ured. 781; Barth, N.. Am. Ured. _ 7267;
Clements, Crypt. Form. Colo. 576.

39: Allodus Bouvardiae (Griff.) comb. nov.

Puccinia Bouvardiae Griff. Bull. Torrey Club 29: 297. 1902.
Aecia hypophyllous, gregarious; aeciospores 19-23 by 23-26 u;
wall I-1.5 w thick, finely verrucose.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 203

Telia chiefly epiphyllous, scattered, pulvinate, ruptured epi-
dermis not conspicuous; teliospores broadly ellipsoid, 26-29 by
35-45 uw; wall 3-4 » thick, chestnut-brown, finely verrucose, the
apex up to 7 uw thick, with a hyaline umbo; pedicel colorless, up to
100 pu long, slightly roughened below.

On Rubiaceae:
Bouvardia triphylla Salisb.
TYPE LOCALITY: Santa Catalina Mts., Arizona, on Bouvardia
triphylla.
DISTRIBUTION: Known only from Arizona.
ExsiccaTi: Griff. W. Am. Fungi 394.

40. ALLODUS AMBIGUA (A. & S.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Aecidium Galit ambiguum A. & S. Consp. Fung. 116. 1805.
Puccinia difformis Kunze, Myk. Hefte 1: 71. 1817.
Puccinia ambigua Lagerh.; Bubak, Sitz.-ber. Bohm. Ges. Wiss.

1898": 14. 1808.

Aecia hypophyllous, grouped on reddish-brown spots; aecio-
spores 14-19 by 17-22 u; wall about 1 yw thick, finely and distinctly
verrucose.

Telia hypophyllous and caulicolous, arising from around the
secondary aecia or scattered, rather long covered by the epidermis,
cinereous; teliospores ellipsoid 14-22 by 31-434; wall light
chestnut-brown, about I w thick, smooth, the apex 6-10 uw thick;
pedicel slightly tinted, up to the length of spore.

On Rubiaceae:
Galium A parine L.
TYPE LOCALITY: Germany, on Galium A parine.
DISTRIBUTION: Ohio to British Columbia and California; also in
Europe.
ExXsIccaATI: Sydow, Ured. 2259; Brenckle, Fungi Dakot. 50;
Barth. N. Am. Ured. 1426.

41. ALLODUS COMMUTATA (Syd.) Arth. Résult. Sci. Congr. Bot.
- Vienne 345. 1906
Puccinia commutata Sydow, Monog. Ured. 1: 201. 1902.

Aecia hypophyllous, gregarious or scattered over leaf, often
on large yellow spots; aeciospores 12-19 by 16-21 uw; wall I-1.5 wu
thick, finely verrucose.

Telia amphigenous, caulicolous, around the secondary aecia,

204 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

circular, rupturing at the apex to form a characteristic ostiole;
teliospores ellipsoid, 20-26 by 39-59 u; wall 1.5-2m thick, dark
cinnamon-brown, the apex 7-9u thick, with a semi-hyaline
umbo; pedicel slightly tinted next to the spore, short.
On Valerianaceae:
Valeriana acutiloba Rydb., V. edulis Nutt., V. occidentalis
Heller, and V. sztchensis Bong. |
TyPeE LocALity: Europe, on Valeriana officinalis.
DISTRIBUTION: British Columbia to New Mexico; also in Europe.
ExsiccatTi: Ell. & Ev. N. Am. Fungi 2277; Barth. N. Am. Ured.
231.

42. ALLODUS INTERMIXTA (Peck) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906

Puccinia intermixta Peck, Bot. Gaz. 4: 218. 1879.

Aecidium intermixtum Peck, Bot. Gaz. 4: 231. 1879.

Dicaeoma intermixtum Kuntze, Rev. Gen. 3°: 469. 1898.

Aecia amphigenous, over entire leaf, apparently from a peren-
nial mycelium: aeciospores, 17-22 by 22-28 uw; wall about 1.5 yu
thick, finely verrucose.

Telia amphigenous, scattered among the aecia, epidermis
rupturing at apex to form a conspicuous ostiole; teliospores
broadly ellipsoid, 20-25 by 31-37 wu; wall 1.5-2 w thick, cinnamon-
brown, very finely verrucose, the apex very slightly thickened to
3 uw; pedicel colorless, short.

On Ambrosiaceae:

Iva axillaris Pursh.
TYPE LOCALITY: Green River, Wyoming, on Iva axillaris.
DISTRIBUTION: South Dakota to Washington and New Mexico.
ExsiccaTi: Ell. & Ev. N. Am. Fungi 2239, 2252a, 2405; Barth.

Fungi Columb. 3761, 3845; Griff. W. Am. Fungi 290; Garrett,

Fungi Utah. 163; Barth. N. Am. Ured. 747, 748, 1454; Ell. &

Ev. Fungi Columb. 63.

43. ALLopus BaATEsIANA Arth. Résult. Sci, Congr. Bot. Vienne
345. 1906
Puccinia Batesiana Arth. Bull. Torrey Club 28: 661. 1901.
Aecia hypophyllous, gregarious or scattered, often on dis-
colored spots; aeciospores, 16-20 by 22-26 uw; wall about I p thick.
Telia chiefly hypophyllous, gregarious, or scattered, often
arising about the aecia, long covered by the epidermis, blackish,

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 205

surrounded in the sori by a well-developed dark brown stroma,
teliospores terete, sometimes truncate above, 15-19 by 45-58 #;
wall about 1 » thick, cinnamon-brown, smooth, the apex 7-16 u
thick; pedicel tinted, short.

On Compositae:

Helicopsis helianthoides (L.) Sweet and H. scabra Dunal.
TypE LocALity: Long Pine, Nebraska, on Helicopsis scabra.
DistRiBuTION: Nebraska, lowa, Minnesota and Delaware.
Exsiccati: Ell. & Ev. Fungi Columb. 1463; Griff. W. Am. Fungi

322; Barth. Fungi Columb. 414r; Barth. N. Am. Ured. 125, 929.

44. ALLODUS TENUIS (Schw.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Caeoma (Aecidium) tenue Schw. Trans. Am. Phil. Soc. IT. 4: 293.
1832.
Puccinia tenuis Burr. Bot. Gaz. 9: 188. 1884.
Dicaeoma tenue Kuntze, Rev. Gen. 3°: 470. 1898.

Aecia hypophyllous, in annular groups on discolored areas or
scattered in small groups over the leaf; aeciospores 11-14 by
12-17 yw; wall about I yu thick, finely verrucose.

Telia chiefly hypophyllous, intermixed with the secondary
scattered aecia, long covered by the epidermis, surrounded in the
sori by a well-developed brown stroma, teliospores fusoid to
cylindrical, 11-14 by 26-34 #; wall cinnamon-brown, about I u
thick, smooth, the apex 5-7 # thick; pedicel concolorous, short.
On Compositae:

Eupatorium urticaefolium Reich. (E. ageratoides L. f.)
Typr LocaLity: Bethlehem, Pennsylvania, on Eupatorium ager-
atoides.
DISTRIBUTION: Vermont to West Virginia, Minnesota, and Iowa.
ExsiccaTi: Ell. N. Am. Fungi 1420, 1838; EIl. Give IN: Am
Fungi 2810; Rab.-Paz. Fungi Eur. 4741; Barth. N. Am. Ured. 65.

45. ALLODUS GNAPHALIATA (Schw.) Arth. Résult. Sci. Congr. Bot.
Vienne 345. 1906
Aecidium gnaphaliatum Schw. Trans. Am. Phil. Soc. Il. 4: 292.
1832.
Puccinia investita Schw. Trans. Am. Phil. Soc. il. 4: 206.. 1932.
Dicaeoma investitum Kuntze, Rev. Gen. 3°: 469. 1898.

Aecia hypophyllous, opposite conspicuous yellow areas on the
leaf, gregarious; aeciospores 17-23 by 20-29 #; wall 1.5-2 p thick,
rather conspicuously verrucose.

206 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Telia hypophyllous, scattered, rather tardily naked; teliospores
clavate to pyriform, 17-25 by 36-53 u; wall dark chestnut-brown,
I-1.5 w thick, smooth, the apex 7—12 yp thick; pedicel light golden,
rarely as long as the spore.

On Compositae:

Gnaphalium californicum DC., G. decurrens Ives, G. lepto-
phyllum DC., G. leucocephalum A. Gray, G. margaritaceum L.,
G. obtusifolium L. (G. polycephalum Michx.), G. oxyphyllum DC.,
and G. semiamplexicaule DC.

TYPE LocaLity: Bethlehem, Pennsylvania, on Gnaphalium poly-
cephalum.

DISTRIBUTION: United States and Mexico.

ExsiccaTi: Ell. & Ev. Fungi Columb. 1285, 1764; Sydow, Ured.

1773; Barth. N. Am. Ured. 549; Ell. & Ev. N. Am, Fungi 3569.

46. ALLopUuS DEsMANTHODII (D. & H.) Arth. Résult. Sci. Congr.
Bot. Vienne 345. 1906
Puccima Desmanthodii Diet. & Holw. Bot. Gaz. 31: 334. Igo01.

Aecia amphigenous, gregarious; aeciospores 14-19 by 17-20 u;
wall 1-1.5 uw thick, with fine deciduous, verrucose markings.

Telia chiefly hypophyllous, gregarious over large areas, usually
surrounding the aecia, long covered by the epidermis, surrounded
in the sori by a dark brown stroma; teliospores terete to cylindrical,
12-16 by 45-61 uw; wall cinnamon-brown, I-1.5 » thick, smooth,
the apex 5-8 » thick; pedicel concolorous, up to the length of
spore.

On Compositae:
Desmanthodium fruticosum Greenm. and D. ovatum Benth.
TYPE LOCALITY: Oaxaca, Mexico, on Desmanthodium ovatum.
(Holway, 3665, Oct. 18, 1899.)
DISTRIBUTION: Mexico.
ExXsIccATI: Barth. N. Am. Ured. 234, 1540.

47. ALLODUS SUBCIRCINATA (E. & E.) Arth. Résult. Sci. Congr.
Bot. Vienne 345. 1906
Puccima subcircinata Ell. & Ev. Jour. Myc. 3:56. 1887.
Dicaeoma subcircinatum Kuntze, Rev. Gen. 3°: 470. 1898.
Aecia hypophyllous, annular, or in small groups on conspicu-
ous yellow areas of the leaf; aeciospores 16-19 by 17-20 uw; wall
I-1.5 uw thick, finely verrucose.

ORTON: NORTH AMERICAN SPECIES OF ALLODUS 207

Telia chiefly hypophyllous, surrounding the secondary aecia
or scattered, sometimes confluent to form large sori, rupturing at
the apex to form a conspicuous ostiole; teliospores broadly ellip-
soid, 15-21 by 25-32; wall chestnut-brown about 1.5 uw thick,
smooth, the apex sometimes thickened to 3 uy; pedicel colorless,
rarely as long as the spore.

On Compositae:
Senecio atriapiculatus Rydb., S. crassulus A. Gray, S. dispar

A. Nels., S. hydrophilus Nutt., S. hydrophilus pacificus Greene,

S. integerrimus Nutt., S. lugens Rich., S. taraxacoides (A. Gray)

Greene, and S. triangularis Hook.

TYPE Locality: Mt. Paddo, Washington, on Senecio triangularts.

(Suksdorf, Aug. 1885.)

DISTRIBUTION: Nebraska to California and British Columbia.
Bxsrecati: Bln & Ey No Am. Fungi 7870; Ele-& Ev. Funes

Columb. 1459; Sydow, Ured. 782, 1943; Garrett, Fungi Utah.

29, 106; Barth. Fungi Columb. 4468; Barth. N. Am. Fungi

Weyl, 1372.

Note.—This species is distinguished from Allodus Senecionis
(Lib.) Arth. by the slightly smaller aeciospores and the scarcely
thickened apex of the teliospores, without the hyaline umbo.
A. Senecionis is not known to occur in North America.

INDEX TO SPECIES

Aecidium
Cerasti, 199
claytoniatum, 184
convolvulatum, 197
Galii ambiguum, 203
Giliae, 199
gnaphaliatum, 205
graminellum, 180
intermixtum, 204
Ipomoeae, 195

Ipomoeae-panduranae, 197 .

Leptotaeniae, 190
Ludwigiae, 189
monoicum, 188
Nesaeae, 189
Phlogis, 199
Podophylli, 186
podophyllatum, 187
Swertiae, 195
tenue, 205
Wilcoxianum, 199

Allodus
ambigua, 177, 203
areolata, 186
asperior, 193

Batesiana, 177, 204
Bouvardiae, 202
Calochorti, 181
Carnegiana, 182, 183
Chamaesarachae, 177, 201
claytoniata, 177, 184, 185
commutata, 203
consimilis, 177, 187
crassipes, 196
Desmanthodii, 206
Dichelostemmae, 183
Douglasii, 177, 198
effusa, 188
Erigeniae, 191.
gigantispora, 185
Giliae, 177, 199
gnaphaliata, 205
graminella, 178, 180
imperspicua, 189
insignis, 197
intermixta, 177, 204
Jonesii, 190

lacerata, 194
Lindrothi, 192
Ludwigiae, 189
megalospora, 198
melanconioides, 194

mellifera, 200
microica, 192
Moreniana, 182
Musenii, 193
Nesaeae, 189
nocticolor, 197
opposita, 185
opulenta, 195
oregonensis, 193
pagana, I81
Palmeri, 202
plumbaria, 199
Podo, ny li, 178, 186
rufescens, 202
subangulata, 183
subcircinata, 206
superflua, 198
Senecionis, 207
Swertiae, 195
tenuis, 205
vertisepta, 200

Caeoma

claytoniatum, 184
podophyllatum, 187
tenue, 205

208

Dasyspora

Anemones-virginianae, 185

Dicaeoma
anachoreticum, I81
arabicola, 199
areolatum, 186
asperius, 193
claytoniatum, 184
Clematidis, 185
consimile, 187
crassipes, 196
Cymopteri, 190
Douglasii, 198
fragile, 199
Holwayi, 181
intermixtum, 204
investitum, 205
Ipomoeae, 196
Jonesii, 190
melanconioides, 194
microicum, 192
Nesaeae, 189
opulentum, 195
plumbarium, 199
Podophylli, 187
rufescens, 202
subcircinatum, 206
Swertiae, 195
tenue, 205
Violae, 188

Diorchidium
Tracyi 201

Allium, 181, 182
Anemone, 185, 186
Arracacia, 189, ‘190, 192
Audibertia, 200
Aulospermum, I90
Bouvardia, 203
Brodiaea, 182, 183, 184
Calochortus, 182
Caltha, 186
Chamaesaracha, 201
Claytonia, 184, 185
Cogswellia, 190
Collomia, 199
Cryptotaenia, 192
Cymopterus, 190, 191
Cynomarathrum, 190
Deringa, 192
Desmanthodium, 206
Deweya, 192
Dichelostemma, 183, 184
Dipterostemon, 182, 183

MEMOIRS OF THE NEW

Puccinia

ambigua, 203
anachoreta, 181
arabicola, 199
areolata, 186
asperior, 193
aurea, 187
Batesiana, 204
Bouvardiae, 202
Calochorti, 181
Carnegiana, 182

Chamaesarachae, 201

claytoniata, 184
commutata, 203
consimilis, 187
crassipes, 196

Cryptotaeniae, 192

Cymopteri, 190
deBaryana, 185

Desmanthodii, 206
Dichelostemmae, 183

difformis, 203
effusa, 188
fragilis, 199

gigantispora, 185

gillicola, 199
graminella, 180
Holboelli, 188
Holwayi, 181
imperspicua, 189
insignis, 197
intermixta, 204
investita, 205
Ipomoeae, 196
japonica, 186

Dodecatheon, 195
Drudeophytum, 192
Erigenia, 191
Eupatorium, 205
Exogonium, 196
Ferula, 191, 193
Galium, 203

Gilia, 199, 200
Gnaphalium, 206
Helicopsis, 205
Hookera, 183, 184
Ipomoea, 196, 197, 198
Iva, 204
Leptodactvlon, 199
Leptotaenia, 190, 191, 193
Linanthus, 200
Lomatium, 190
Ludwigia, 189
Microsteris, 199, 200
Montia, 184

aculeata, 186, 187

YORK BOTANICAL GARDEN

Jonesii, 190
Lindrothii, 192
Ludwigiae, 189
Mariae-Wilsoni, 184
melanconioides, 194
mellifera, 200
microica, 192
Moreniana, 182
Musenii, 193
Nesaeae, 189
nocticolor, 197
nodosa, 182, 183
opulenta, 195
oregonensis, 193
pagana, 181
Palmeri, 202
plumbaria, 199

plumbaria phlogina, 199
Podophylli, 176, 178, 186,

187
Purpusil, 199
Richardsonii, 198
rufescens, 202
Saniculae, 194
Seymourii, 193
sphalerocondra, 192
subangulata, 183, 184
subcircinata, 206
superflua, 198
Swertiae, 195
tenuis, 205
Traversiana, 190
tumamocensis, 183
vertisepta, 200
Wilcoxiana, 199

INDEX TO HOST GENERA

Musineon, 191, 194
Oreoxis, 194
Pedicularis,202 .«
Pentstemon, 202
Peucedanum, 190, I9I
Phabartis, 196
Phellopterus, 191
Phlox, 199, 200
Podophyllum, 187
Pseudocymopterus, 194
Pteryxia, 191

Salvia, 200, 201
Sanicula, 192, 193, 194
Senecio, 207

. Sisymbrium, 188

Stipa, 181
Swertia, 195
Valeriana, 204
Velaea, 192
Viola, 174, 188

THE DEVELOPMENT OF LEPIOTA CRISTATA AND
L. SEMINUDA

GEo. F. ATKINSON

Cornell University
(WITH PLATES 21-26)

INTRODUCTION

The development of the fruit body in the Agaricaceae, with
special reference to the differentiation and organization of the
principal parts, has been studied in comparatively few forms.
Approximately sixty species representing some twenty genera
have been examined. More than three fourths of these species
were studied during a comparatively early period, from 1842 to
1889, when the methods of technique employed were less satis-
factory than at the present time. Consequently many of the
species studied during that period were more or less imperfectly
examined. During the last decade less than a dozen species have
been studied. Owing to progress in technique, this study has been
correspondingly intensified and more satisfactory results have
been obtained.

The unfolding of the parts of the fruit body, after their organiza-
tion in the young basidiocarp, has been studied in a large number
of species. But this phase of the work relates almost wholly to
macroscopic observations on the gross morphology. These studies
of the grosser features in development cover a period of about
one hundred years, beginning early in the nineteenth century, when
the science of mycology began to emerge from its mystic age.
These morphological features have been the chief elements on
which all our taxonomic systems of- the fungi have been based.
We continue to shuffle them into new patterns, or dies, for the
rearrangement of present, or the manufacture of new genera,
without a clear understanding, in many instances, of their real
taxonomic significance.

A study of the origin, differentiation, and organization of the

15 209

210 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

parts of the basidiocarp in the Agaricaceae is essential to a clear
understanding of their taxonomic value. There is needed a study
of development of many more species representing all the principal
genera and their subdivisions, as well as some of the lesser ones,
before we shall be in a position safely to make any generalizations
in regard to the prevalence of any mode of origin or development
of the principal parts of the fruit body, or of their relative taxono-
mic importance. These studies on the development of Lepzota
cristata and L. seminuda are offered as a further contribution to
this subject. They deal chiefly with the origin, differentiation,
and organization of the pileus, stem, lamellae, and veil, in the young
primordial basidiocarps. The origin of the primordial basidio-
carp, and the nuclear phenomena in the ontogenetic cycle, while
exceedingly interesting and important problems, do not appear,
so far as we know at present, to be closely correlated with the
differentiation of the parts in the primordial fruit body.

LEPIOTA CRISTATA

Material.—Lepiota cristata is a small plant, usually about 4-6
cm. high, with a pileus 1-2.5 cm. broad, and the stem 2-4 mm.
thick. The general color is whitish, the pileus being adorned with
numerous dark, fibrous, more or less erect scales formed by the
laceration of its upper surface, more crowded over the center, thus
giving the plant a cristate appearance. It occurs singly, or more
frequently in troops; rarely are the plants so closely clustered that
two or three may be joined at the base. It grows on the ground
in woods and open places from spring until autumn. The material
for this study was collected, fixed in chromacetic and imbedded
in paraffin by Miss Gertrude Douglass during the summer of 1914.
The plants were gathered chiefly along Cascadilla Creek by a path
in a grove of mixed hemlock spruce and hard timber, mainly oak;
some also from a similar grove by a path along Fall Creek, the
two streams bordering the Cornell University Campus on the
south and north sides. Where the plants occur in troops there is
usually an abundance of the ‘‘spawn”’ in the soil and individuals
in all stages of development are to be found. In such cases, the
spawn often continues to produce fresh individuals for a period
of one to several weeks. This succession of individuals distributed
on the spawn, when weather conditions are favorable, assures the

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA Zila

normal organization and development of the young basidiocarps.
The material was sectioned, and stained with fuchsin, by the
writer.

Differentiation of pileus and stem fundaments.—The youngest
basidiocarps examined were rather long-ovate in form, I mm.
long by 0.5 mm. in diameter (FIG. 1). At this stage there is no
differentiation into pileus and stem primordia. But the young
fruit body is slightly differentiated into a basal area of a more
compact texture, oval in form, the rounded apex extending into
the upper area of looser texture which fits over it somewhat like
a mitrate calyptra, the elements of the two areas merging along
the border zone. The basal area takes the stain more deeply,
the hyphae are rather intricately interwoven, while those of the
upper region extend more or less in a longitudinal direction. In
the mitriform area the general direction of the hyphae is also
longitudinal, but they are more or less interwoven. Those over
the apex, or crown, are thus more or less perpendicular to the
surface, while those on the lateral face below the crown are parallel
with the surface.

The basal portion of the young fruit body is the ‘‘foot,’’ the
basal part of the stem, corresponding to the bulb. From the
apex of this the stem fundament arises endogenously by new
growth of hyphal branches upward and by interstitial elongation.
This new growth area progresses toward and partly into the
mitriform area above, where it begins to expand laterally, forming
the pileus primordium. Stem and pileus primordia at this stage
form an internal area somewhat sheaf-shaped in outline as shown
in FIGURE 2. The mitriform area at this stage belongs chiefly
to the blematogen, but the boundary between blematogen and
pileus primordium is very indefinite. The blematogen also
extends down on the stem fundament. The hyphae of the
blematogen layer above and on the flanks of the pileus fundament
are radial and somewhat interwoven, but are more nearly parallel
in their arrangement than in younger stages represented by
FIGURE I.

Origin and development of the hymenophore primordium.—The
pileus primordium continues to enlarge by radial growth and by
the origin of new hyphal branches. On the lower marginal
periphery numerous new hyphal branches arise, extending laterally

lee MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

and somewhat downward, at an oblique angle from the stem axis.
These branches at first are more or less isolated, are slender,
and make their way through the loose mesh of the ground tissue.
As they increase in number they become more or less crowded,
and parallel. This internal annular zone of new growth is the
primordium of the hymenophore and pileus margin (FIGS. 3-6).
The hyphae are rich in protoplasm and stain deeply in contrast
to the hyphae of the ground tissue and of the pileus and stem
fundaments. In median longitudinal section of the young
basidiocarps, the hymenophore fundament appears as two sym-
metrically disposed deeply stained areas near the margin of the
pileus above the weakly developed annular cavity as shown in
FIGURE 3. Its character is more clearly seen in longitudinal
“‘tangential’’ sections.

FIGURE 4 is from a “‘tangential’’ section of the same basidio-
carp, parallel with the stem axis and through the hymenophore
primordium. The light area is the weak annular cavity with
shreds of the ground tissue extending across the cavity. The
slender hyphae above the cavity are those of the hymenophore
primordium. They are parallel, but not very crowded, their ends
do not form an even lower surface, but their different lengths and
loose arrangement indicate a fimbriate condition of the hymeno-
phore primordium. FIGURE 6 is from a similar section of another
basidiocarp. The annular cavity is not so well formed, but the
character of the hymenophore primordium is well shown. FIGURE
5 is from a section of the same basidiocarp (as represented in
FIGURE 6), also “tangential,’’ butit runs through the stem surface
in the angle at the.junction of pileus and stem. The hymenophore
is therefore not continuous in this section, but is shown as two
broad deeply stained areas one on either side of the central pileus
tissue.

Origin of the general annular gill cavity—The rapid increase
in the elements of the hymenophore, and their increase in diameter
as the primordial stage of the hymenophore changes to the palisade
stage, together with the centrifugal and epinastic growth of the
pileus margin,! produces a tension on the ground tissue below

‘For a full discussion of the organization and development of the hymenophore

and its relation to the annular cavity see Atkinson, Geo. F. Morphology and develop-
ment of Agaricus Rodmani. Proc. Am. Phil. Soc. 54: 309-343. pl. 9-13. 1915.

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA 2s

which ruptures it and forms an internal, annular cavity below
the hymenophore primordium. Since the lamellae are later
formed in this cavity, as downward projecting salients, it is known
as the general annular prelamellar (or gill) cavity. In Lepiota
cristata this cavity is not proportionately so large as in Lepiota
seminuda described later in this paper. It is weak in the FIGURES
3 to 6, but as the palisade area is organized and the gill salients
begin to form the annular cavity is more pronounced. It is as
broad as the area between the stem and margin of the pileus,
but not very deep, as shown in FIGURES 7-17. The epinastic
growth of the margin of the pileus lifts the veil up to some extent,
thus narrowing the cavity, but in the cases observed the veil is
not crowded against the margin of the lamellae, as sometimes
occurs in the species of the genus Agaricus (Atkinson, ’15). It
may very likely occur in certain individuals of Lepiota cristata.

Origin of the lamellae—The growth of the pileus margin is
centrifugal. The extension of the hymenophore primordium,
developed on its under surface is therefore also centrifugal, the
older stages being next the stem and the younger ones next the
margin of the pileus. As the primordium of the hymenophore
ages, the hyphae increase in number by new branches crowding
in between the older ones. The hyphae also increase in diameter,
becoming parallel and closely packed side by side. Their free
ends also come to reach the same level, thus forming an even
palisade layer. This begins next the stem and proceeds in a
centrifugal manner toward the margin of the pileus, the primordial
condition of the hymenophore gradually becoming changed into
the palisade condition.

The lamellae arise as downward growing radial salients of the
level palisade. These salients begin next the stem and progress
centrifugally toward the margin of the pileus (for details of this
process see Atkinson, ’15). FiGuURES 7-12 show the origin of
the lamellae in one fruit body. The sections from which the
photographs were made were selected from a series of sections
passing from the middle of the pileus toward its margin. FIGURE
7 is a median longitudinal section, and is therefore nearly or quite
parallel with the lamellae. At the left side of the figure the
section passes parallel with and through the lamellae, while on
the right it passes in a slightly oblique direction. FIGURE 8 is

214 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

from a section on one side of the central axis of the stem. At the
left a gill salient is shown cut obliquely, while at the right the
section is from between two adjacent lamellae. In FIGURE 9 the
section is ‘‘tangential’’ and not far from the angle of the junction
of stem and pileus; since the lamellae are free from the stem, no
salients are present over the middle area of this section, but on
either side a few salients are shown which are cut nearly, but not
quite in a transverse direction, since they radiate outward from
near the stem. In FIGURE 10, still farther away from the stem, a
few very low salients are present over the middle area which are
cut transversely, while the lamellae on either side, farther from the
stem, are cut obliquely, those nearer the pileus margin more so than
those toward the stem. In FIGURE II, from a section a little
farther from the stem, the gill salients over the middle area are
stronger and still more so in FIGURE 12. ‘The salients (FIGs.
It and 12) show but a slight downward extension of the level
palisade area. Here are the extreme “‘posterior’’ ends of the
lamellae, which remain as very low and more or less rudimentary
salients. From the extreme “posterior” ends of the lamellae they
increase rapidly in breadth for the mature lamellae are broader
at some distance from the end and then round off behind (next the
stem). The middle salients in FIGURES II and 12, at this distance
from the stem, are arrested in growth immediately, or very soon
after their downward extension from the level palisade.

FIGURES 13-16 are from a similar series of sections of another
basidiocarp. FIGURE 15 is from a “‘tangential’’ section the middle
area of which passes through the sterile area between the stem and
posterior ends of the lamellae. For sake of clearness it may be
mentioned that in typical species of Lepiota the lamellae are free
from the stem, so that there is a circular sterile area of the pileus
between the stem and lamellae, which is of greater or lesser extent
in different species. FIGURE 16 is from a section nearer the margin
of the pileus.

Organization of the blematogen and its union with the pileus
fundament.—In very young basidiocarps, as represented in
FIGURES I and 2, the character of the blematogen has been de-
scribed above. Over the crown of the young basidiocarp and
external to the pileus fundament it consists of slender hyphae
3-6 w in diameter. They extend in a longitudinal direction in

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA Tey

the apex of the primordial basidiocarp, i. e., parallel with the axis
of the stem. They are radial or perpendicular to the upper and
lateral surface of the young pileus primordium after its appear-
ance. While the general direction is radial, the hyphae are more
or less flexuous! and somewhat interwoven. This tissue is loose,
since there are rather conspicuous interhyphal spaces. Lateral
to the stem fundament the hyphae of the blematogen are nearly
or quite parallel to the stem axis, 7. e., they are not radial, or
perpendicular to the surface of the basidiocarp, while they are
radial or perpendicular over the pileus fundament.

As the fruit bodies become older the blematogen becomes
more definitely organized into a compact palisade layer of hyphae
over the pileus and extending a short distance below the margin.
Lower down on the surface of the stem the hyphae remain nearly
or quite parallel with the stem surface. In FIGURES 3 and 5 the
more compact nature of the blematogen layer is manifest. It is
still better shown in FIGURES 7-14 and in FIGURE 17. Here it
forms a distinct layer which can be seen to extend some distance
below the margin of the pileus, but is not so distinct far down
over the stem as it is in Lepiota clypeolaria (see Atkinson, 714).
The radial character of the outer portion of the blematogen is
well shown in FIGURE 17. These radial hyphae are 5-10 in
diameter and 30-40 p long, but in mature specimens the dimensions
are greater. These radial hyphae spring from a thin zone of
pseudoparenchyma, similar to that in Lepiota clypeolaria (loc. cit.),
but not so well marked.

As the pileus primordium increases in growth it becomes
firmly united with the inner zone of the blematogen, so that the
latter becomes concrete with the surface of the pileus, and the
outer surface of the blematogen becomes the surface or ‘“‘cuticle,”’
of the mature pileus as usually understood.

The marginal or partial veil.—The marginal, or partial, veil,
as in species of Agaricus, Lepiota clypeolaria and Armillaria mellea
described by the writer (714, ’15) consists partly of a section of
the blematogen, and partly of ground tissue extending between
the margin of the pileus primordium and the stem, the ground

1 For a discussion of the blematogen and its relation to the volva in Amanita and

Amanitopsis, and to the universal veil in Lepiota clypeolaria, and certain species of
Agaricus, see Atkinson, ’14 and "15.

216 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

tissue undergoing considerable increase during development.
Some growth from the pileus margin is incorporated with it.

LEPIOTA SEMINUDA

Material.—Lepiota seminuda is a very pretty, pure white,
rather small plant, 1-4 or 5 cm. high as it usually occurs in the
vicinity of Ithaca, N. Y. It grows in troops on decaying leaves
and small twigs or branches. It is covered with a loose powdery,
or mealy, substance of globose or broadly elliptical cells from the
blematogen. The partial veil is very frail, and usually clings to
the margin of the expanded pileus, so that the mature plants are
usually exannulate. The slender stem is usually devoid of an
annulus, or has a delicate and fugacious one. Lacking a collar,
it is literally decolleté, and may be said to be seminude. ‘The
material for this study was collected during the summer of 1914,
in Cascadilla Woods on the campus of Cornell University, where
it has been found during a number of past years. The plants
were very numerous, thickly scattered over the leaves and decaying
twigs in a moist thicket, so that all stages from minute plants in
the earliest stages of the differentiation of pileus and stem funda-
ments to maturity were available. They were fixed in chrom-
acetic fluid, and the smaller specimens, as in the case of those of
Lepiota cristata, were lightly stained in toto with eosin, so that
their orientation in the paraffin could be readily seen. The
sections were stained with fuchsin.

The pileus and stem primordia.—The youngest basidiocarp
studied was approximately 0.5 mm. long by 0.25 mm. in diameter.
A median longitudinal section is shown in FIGURE 18. The young
pileus and stem primordia are already organized within the ground
tissue and are enveloped by the blematogen of loose texture.
From the appearance of the sections of this young basidiocarp, I
am inclined to think that the young stem fundament is organized
first and that the pileus is organized later by progressive new
growth in the ground tissue from the stem apex, so that a sheaf-
like structure is formed surrounded by the blematogen: at least
the primordial areas of both stem and pileus are outlined prior to
the organization of the hymenophore fundament.

Organization of the hymenophore primordium.—The hymeno-
phore primordium, as in Lepiota cristata, arises as an internal

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA ALF

annular zone of new growth on the lower side of the margin of the
pileus fundament and is well shown in FIGURE 19. This figure is
from a longitudinal, and nearly median, section of a young basidio-
carp. The hyphae of the hymenophore primordium extend out-
ward and downward at an angle of about 45° from the axis of
the stem. By the introduction of numerous new branches this
internal annular zone of new growth is already quite compact
and takes a deep stain on account of the abundant protoplasm in
the young hyphae. But the lower surface of the hymenophore
primordium is still uneven and more or less frazzled or fimbriate,
since the slender tapering hyphae in their growth through the
ground tissue beneath have not reached the same level and are
less crowded because of their tapering form. This is well shown
in FIGURES 21 and 22, which are from more highly magnified
photomicrographs of the hymenophore and adjacent tissue at
the left side of FIGURE 19.

Even at this young stage the margin of the pileus fundament
and of the hymenophore shows epinastic growth. The trans-
section of the hymenophore presents a slightly arched form,
convex above, concave below. At the extreme left of the hymeno-
phore fundament in FIGURES 21 and 22, the hyphae are more
loosely associated, since this portion of the hymenophore is the
younger. This rapid increase in the elements of the hymenophore
primordium over that of the ground tissue below produces a
pressure which exerts a tension on the loose ground tissue and it
is gradually torn apart, forming the general annular, prelamellar
cavity. A very early stage ‘n the formation of this cavity is
shown in FIGURES 19-22. FIGURE 20 is from a section through
one side of the annular hymenophore primordium parallel with a
tangent to its surface and also parallel with the axis of the stem.
The uneven, ragged lower surface of the hymenophore at this
stage is shown, as well as the early stage of the gill cavity with
isolated hyphae or slender loose strands extending across the
weak cavity.

Organization of the level palisade.—Since growth of the pileus
margin and of the hymenophore primordium is centrifugal, the
older stage of the hymenophore is next the stem. It is in this
region that the primordial stage of the hymenophore first passes
over into the level palisade stage by increase in the number of the

218 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

hyphal branches, by their increase in diameter, and by the free
ends of the hyphae reaching the same level. This stage is well
shown in FIGURES 23 and 24 from a slightly older basidiocarp.
The general plane of the under surface of the hymenophore rises
at a strong oblique angle from the stem, but epinasty of the pileus
is curving the margin downwards. In FIGURE 24 the axis of the
stem is at the right. The palisade condition of the older portion
of the hymenophore, 7. e., the portion at the right, near the stem,
is well shown. The free ends of the hyphae now register and
form an even, or ‘“‘level,’’ surface. The younger portion, at the
extreme left, is still in the primordial stage as shown by the more
slender hyphae and the unregistered position of their free ends.

FIGURE 25 is from a ‘‘tangential’”’ section of the same basidio-
carp. This palisade stage of the hymenophore is shown over the
middle area which is not far from the stem, while on either side,
farther away from the stem, the hymenophore is still in the pri-
mordial stage. In older! basidiocarps, represented by “‘tangen-
tial’’ sections in FIGURES 27-31, the level palisade is shown to be
well established prior to the origin of the gill salients. [FIGURE 26
is from the same fruit body, but is from a median longitudinal
section, and thus being parallel with the direction of the young
lamellae, one cannot determine with certainty whether or not
the fundaments of the lamellae have begun their appearance.
None are evident on one side of the basidiocarp shown in FIGURES
27 and 28, nor on the left side of FIGURES 29 and 30 from the
opposite side.

The annular prelamellar cavity—The general annular, pre-
lamellar cavity is large and well formed in Lepiota seminuda before
the lamellae begin their development. The formation of the
cavity begins early by tension on the ground tissue underneath
the expanding hymenophore primordium. It rapidly enlarges
with increased growth of the hymenophore and pileus, so that on
transsection it is circular or elongate, as shown in FIGURES 23, 26,
and 32, or broadly elliptical in ‘‘tangential’’ section, as in FIGURES
25,2728, 30,,andrgl,

Origin of the lamellae——Since the prelamellar cavity attains
such a large size in comparison with the small size of the fruit body,

1 For a full description and method of interpretation of sections of the basidiocarp,

with the aid of diagrams, see Atkinson, Morphology and development of Agaricus
Rodmani. Proc. Am. Phil. Soc. 54: 309-343. pl. 9-13. 1915.

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA 219

the origin of the lamellae is very clear. Another feature which
adds to the clear and easy interpretation of the origin of the lamellae
is found in the broad and distant primary salients, as well as in the
proportionally broad sterile zone between the gills and stem.
The lamellae arise as downward growing salients of the level
palisade area of the hymenophore. In the basidiocarp repre-
sented in FIGURES 27-31, very slight but broad salients had begun
to form on one side, while on the other side the hymenophore was
still in the level palisade stage. In FIGURES 27 and 28 there is
no evidence of the downward folding or growth of the palisade
layer to form the young lamellae. On the other side of the
hymenophore, shown in FIGURES 30 and 31, there are slight, but
distant downward folds of the palisade area. In FIGURE 29
there is scarcely any evidence of such downward growth, unless
it be at the right hand in the middle of the arched hymenophore.
This longitudinal section just passes through the surface of the
stem at the angle of junction of the pileus and stem. FIGURE 30
is from a section farther from the stem, with slightly greater
magnification. At the right there is a single broad salient, much
more marked than the very slight fold at its posterior end shown
in FIGURE 26. FIGURE 31 is from a section still farther from the
stem. Here are shown four broad salients, the strong one at the
right being a section of the same gill fundament as the one in
FIGURE 30. ‘The other three are much lower salients and repre-
sent the earliest downward growth of the level palisade to form
the gill salients.

FIGURES 32-36 represent sections of a slightly older basidio-
carp, selected from a series passing from the middle of the stem
and pileus to the margin of the pileus, all parallel with the axis of
the stem. FIGURE 33 at some distance from the stem shows four
strong salients, and one low one of a secondary gill at the left.
At the extreme right and left the hymenophore is still in the
primordial stage. FIGURE 34 is stil] nearer the margin of the
pileus, where the two low salients are younger stages of the two
middle ones shown in FIGURE 33. FIGURE 35 is still nearer the
margin of the pileus and these two salients are still younger and
lower, while in FIGURE 36, yet nearer the pileus margin, there is
only a very slight suggestion of two low and broad folds of the
level palisade. On either side the hymenophore is still in the
primordial stage.

220 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Organization of the stem.—The stem fundament represented
in FIGURE 18 is quite homogeneous, consisting of slender longi-
tudinal hyphae, nearly parallel, but more or less interwoven. The
tissue at the base, perhaps not strictly belonging to the stem
proper, but forming the foot, is somewhat more dense. As the
plants age the stems become slightly differentiated. | The core of
the stem does not keep pace in growth with the rather thick
external cylindrical portion. Asa result the stem becomes hollow.
This probably is partly due to a lesser growth of the center, but
perhaps is to be attributed chiefly to the rapid growth of the
exterior, thus producing a tension which tears the core apart,
first leaving it in a more or less shredded condition, until finally
it becomes hollow. Except for a thin external layer the hyphae
of the stem increase greatly in size, come to lie strictly parallel,
and the protoplasm in the stout cylindrical cells becomes attenuate.
A thin external layer is made up of more slender cells rich in
protoplasm. This layer stains more deeply and is well shown in
FIGURES 26, 27, 29, and 32. The parallel hyphae of the stem
continue up to the junction of the stem and pileus. Near the
apex of the stem the cells become shorter, but are still parallel.
The transition to the pileus trama is rather abrupt, shown by
the looser texture of the pileus trama and the strongly interwoven
hyphae. The hyphae in the periphery of the stem apex curve
rather abruptly into the lower surface of the pileus trama adjacent
to the hymenophore, a thin zone of which has a denser texture
than the main part of the pileus trama.

The blematogen.—The blematogen consists of a rather thick
zone of radiating hyphae, quite distinct from an early stage.
When the pileus fundament is first organized the limits between
pileus and the blematogen layer are very indefinite. But as the
hymenophore and pileus margin are organized the limits are more
clearly discerned. Later as the surface of the pileus becomes
better outlined the limits between blematogen and pileus are
quite clear. The cells of the blematogen layer become very large
and globose or subglobose. The hyphae become strongly con-
stricted at the septa, and very likely the middle lamellae become
weakened so that the cells readily separate. These loose cells
form the ‘‘powder” or ‘‘meal,’’ which makes so conspicuous a
covering on the pileus and stem. The blematogen therefore

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA 221

crumbles and with light friction is easily removed down to the
surface of the pileus. But since no definite pileus surface layer is
organized as in certain species of Coprinus as in C. micaceus, C.
radians, etc., the pileus does not become smooth by desquamation
as it does in those species. The distinction between blematogen
and pileus and stem is well shown in FIGURES 23, 26-28, 32, and 33.
In FIGURES 26-28 it has cracked away from the pileus leaving the
surface of the latter rough from fragments of the blematogen or
‘universal veil,’’ which are still concrete with the pileus surface.

The partial veil—The partial veil, as in Lepiota cristata, con-
sists of a short section of the blematogen, and of the ground
tissue between the margin of the pileus and the surface of the
stem. This ground tissue forms a thin zone in comparison with
the thick zone of the blematogen. In FIGURE 37 it is about one-
third the thickness of the blematogen, but a large portion of the
latter has crumbled away. The proportion is better shown in
FIGURE 23, where the ground tissue is about one-fourth to one-fifth
of the blematogen, but the limit between the two elements is not
definitely drawn. At and just below the apex of the stem the
thickness of the ground tissue of the partial veil is much greater.

PRIMARY DIFFERENTIATION OF BASIDIOCARP

In the species of Agaricaceae with endogenous origin of the
hymenophore, there appear thus far to have been described three
types of differentiation of pileus, stem, and hymenophore funda-
ments in the primordium of the young basidiocarp.

1. The pileus area or primordium, is outlined first, as repre-
sented by Hypholoma sublateritium and H. fasciculare (Miss Allen,
706; Beer, °11), Amanita rubescens (deBary, ’66, ’84, ’87),
Amanitopsis vaginata (Atkinson, ’714). This type was observed
by Fayod (’89, p. 279). The pileus primordium he called the
“couche piléogéne.’’ He arrived at the conclusion that this type
prevailed in the Agaricaceae.

2. The hymenophore primordium is outlined first. This type
is represented by Agaricus campestris (Atkinson, ’06), Agaricus
arvensis (Atkinson, °14), Agaricus Rodmani (Atkinson, ’15),
Armillaria mellea (Atkinson, 714), and Stropharia ambigua (Zeller,
14),

3. The stem fundament is outlined first, followed by the pro-

222 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

gressive differentiation of the pileus area from its apex, followed
by the differentiation of the hymenophore fundament, represented
by Lepiota cristata and L. seminuda.

A similar type is presented in the development of Rozites
gongylophora according to the account by A. Moller (’93, p. 70),
who describes also the presence of an outer envelope (homologous
with the blematogen) and an inner envelope (which forms the
partial veil proper). His description of the origin of the hymeno-
phore primordium, the palisade stage, the origin of the general
annular prelamellar cavity, as well as the origin of the gills by
downward growing radial processes of the palisade stage, is in
entire harmony with the account given here of the procedure in
Lepiota cristata and L. seminuda. The morphology of Rozites
gongylophora is that of a typical Lepiota and the spores examined
in water are white, although the spore mass is bright ochre color.

In some of these species the precedence in the differentiation
of one or another part of the fruit body seems to vary to some ex-
tent. In Agaricus arvensis it appears that the pileus area may be
differentiated simultaneously with the hymenophore primordium,
and in Lepiota clypeolaria it would appear that the stem and
pileus fundaments may be differentiated simultaneously or possibly
in some cases the stem primordium may precede that of the
pileus.

Another type is described by Fischer (’09) in Armillaria
mucida. He states that the pileus is differentiated first by the
appearance of a palisade layer of radial hyphae at the apex of the
basidiocarp primordium, and underneath the very thin “uni-
versal veil’’ (?protoblem). The organization of the palisade
progresses down the sides and then inward over the under surface
of the pileus, there forming the palisade stage of the hymenophore.
This type is so unusual that its confirmation would seem desirable.
It may be pointed out, however, that some species of the agarics,
notably some species in the genus Marasmius, have similar
cystidia in the hymenium and surface of the pileus, which suggests
a possible close relation in the origin of these surfaces. From the
account given by Fischer it would seem that the “universal
veil’? which he describes is a protoblem and that the blematogen
is absent, since the pileus surface and hymenophore primordium
are continuous. ‘Thus, leaving the protoblem out of account, the

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA 223

origin of the hymenophore would be similar to the method in
certain gymnocarp forms.
SUMMARY

1. In Lepiota cristata the stem fundament is first organized in
the base of the young basidiocarp. The pileus fundament is
later organized by progressive growth and differentiation from
the stem apex, the stem and pileus fundaments together forming
a sheaf-like internal area enveloped by ground tissue and the
blematogen. The organization of the stem and pileus funda-
ments in Lepiota seminuda is probably similar, for the fundament
of the two forms a similar internal sheaf-like area.

2. The hymenophore primordium in both species arises by
numerous branches rich in protoplasm, extending outward and
downward from the lower outer margin of the pileus primordium.
The pileus margin is also organized in connection with the hymeno-
phore fundament. . Together they form an internal, annular zone
of new growth. Continued marginal growth by the origin of
new elements extends the hymenophore and pileus margin in a
centrifugal direction.

3. The primordial stage of the hymenophore is characterized
by parallel slender hyphae whose general direction of growth is
downward, but it becomes arched by epinastic growth of the pileus.
In the primordial stage of the hymenophore the lower surface is
loose and velvety, or fimbriate, and the free ends of the hyphae
lack register, z. e., they show an unequal reach. The primordial
stage passes to the level palisade stage of the hymenophore by
increase in number and thickness of the hyphal branches, and by
the register of their free ends, so that a compact even under surface
is formed. This begins next the stem and progresses in a centrif-
ugal direction toward the margin of the pileus.

4. The lamellae arise as downward growing radial salients of
the level palisade. The gill salients begin on the older portions
of the hymenophore palisade and proceed in a centrifugal direction
toward the margin of the pileus. Thus, at an intermediate stage
of development of the young basidiocarp, three stages of hymeno-
phore development are present, the primordial zone next the
pileus margin, preceded by the level palisade zone, and this by
the zone of young gill salients next the stem. These progress in a
centrifugal direction until the primordial stage is transformed into
the level palisade and the latter into the gill salients.

224 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

5. A general, annular, prelamellar cavity is present in both
species. The ground tissue beneath the young annular hymeno-
phore zone lags behind the latter in growth and the tension
thus arising tears the ground tissue apart, forming a general
annular cavity into which the gill salients extend. It is distinct
in both species, but very large in L. seminuda in comparison with
the size of the basidiocarp.

6. The blematogen (‘‘universal veil”’ p. p. of Fries and other
writers) is prominent in both species, but more striking in Lepiota
seminuda than in L. cristata. In the latter species, in the young
stage, it consists of radiating, slender, more or less flexuous hyphae
over the pileus area, and of longitudinal hyphae parallel with the
stem axis, below the pileus area. As the pileus is organized and
becomes concrete with the blematogen, the latter over the pileus
and for a short distance below the pileus margin, becomes organ-
ized into a definite duplex layer, the outer zone consisting of a
compact palisade of cylindrical hyphae, the inner forming a thin
zone of small-celled pseudoparenchyma. With the expansion of
the pileus the blematogen layer over the pileus becomes torn into
more or less erect fibrous scales, giving the pileus a cristate appear-
ance. In Lepiota seminuda the radial hyphae forming the blema-
togen become transformed into chains of globose or subglobose
cells which easily fall apart, giving a mealy or powdery appearance
to the basidiocarps. The blematogen thus crumbles easily and
with slight friction may nearly all be rubbed off the pileus, leaving
only fragments of it attached to the pileus surface. But it does
not become separated from the pileus by a cleavage layer as the
volva of the Amanitae is, nor does complete desquamation take
place by the formation of a well-defined outer pileus layer as in
certain species of Coprinus.

BIBLIOGRAPHY

1906. Allen, C. L. The development of some species of Hypholoma.
Ann. Myc. 4: 387-394. pl. 5-7. 1906.

1906. Atkinson, G. F. The development of Agaricus campestris.
Bot. Gaz. 42: 241-264. pf, 7-12. 1906.

1914. The development*of Agaricus arvensis and A. comtulus.
Am. Jour. Bot. 553-22, $f Gym 1914.
1914. The development of Armillaria mellea. Myc. Centralb.

4: I13-121. $l, 7, 2. 1914,

1914.
IQT4.
1914.
IQI5.
1859.
1866.
1884.
1887.
TOUT.
TO77.
1889.

1909.

1856.

1860.

1861.

ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA 225

Homology of the universal veil in Agaricus. Myc.

Centralb. 5: 13-19. pl. 1-3. I914.

The development of Lepiota clypeolaria. Ann. Myc.

12: 346-356. pl. 13-16. 1914.

The development of Amanitopsis vaginata. Ann.

Niyc..12:200-362.-)). 77-10. “1914.

. Morphology and development of Agaricus Rodmant.
Proc. Am. Phil. Soc. 54: 309-343. pl. 7-13. 8S diagrams. 1915.

Bary, A.de. Zur Kenntniss einiger Agaricinen. Bot. Zeit. 17:
385-388 ; 393-398; 401-404. pl. 13. 1859.

Morphologie und Physiologie der Pilze, Flechten und

Myxomyceten. Leipzig, 1866.

Vergleichende Morphologie und Biologie der Pilze,

Mycetozoen und Bacterien. 1884.

Comparative morphology and biology of the fungi,
mycetozoa and bacteria. Oxford, 1887.

Beer, R. Notes on the development of the carpophore of some
Agaricaceae. Ann. Bot. 257: 683-689. pl. 52. I9I1I.

Brefeld, O. Botanische Untersuchungen iiber Schimmelpilze 3:
1-226. pl. r-1r. 1877.

Fayod, V. Prodrome d’une histoire naturelle des Agaricinées.
Ann. sci. Nat. Bot. VIl.g: 181-411. pi..6; 7, 1880.

Fischer, C. C. E. On the development of the fructification of
Armillaria mucida Schrad. Ann. Bot. 23: 503-507. pl. 35.
1909.

Hoffmann, H. Die Pollinarien und Spermatien von Agaricus.
Bot. Zeit. 14: 137-148; 153-163. pl. 5.. 1856.

Beitrage zur Entwickelungsgeschichte und Anatomie

der Agaricinen. Bot. Zeit. 18: 389-395; 397-404. pl. 13, 14.

1860.

Icones analyticae fungorum. Abbildungen und Be-
schreibungen von Pilzen mit besonderer Riicksicht auf Anatomie
und Entwickelungsgeschichte, I-105. pl. I-24. 1861.

Levine, M. The origin and development of the lamellae in
Coprinus micaceus. Am. Jour. Bot. 1: 343-356. pl. 39, 40.
1914.

Moller, A. Die Pilzgarten einiger siidamerikanischer Ameisen.
Bot. Mittheil. Tropen 6: 1-127. pl. 1-7. 1893.

Zeller, S. M. The development of Stropharia ambigua. Myco-
logia 6: 139-145. pl. 124, 125. I914.

226 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Explanation of plates 21-26

(Photographs by the author)
PLATE 21
Lepiota cristata, various forms from the vicinity of Ithaca, N. Y.

PLATE 22

Lepiota seminuda. Upper group from Cascadilla Woods, Campus, Cornell Uni-
versity (No. 5351 Cornell Univ. Herb.). Middle group, part of same magnified nearly
two times, showing the mealy stem and pileus. Lower group from a spruce forest in
the Jura Mountains, France, near Pontarlier.

PLATES 23-26

The magnifications of the photomicrographs are as follows: Fig. 38; 25 diameters.
Figs. 13, 14, 15, 16; 30 diameters. Figs. 7, 8, 9, 10, II, 12; 35 diameters. Fig. 32;
42 diameters. Fig. 23; 50 diameters. Figs. I, 2, 3, 5, 17; 60 diameters. Figs. 26, 27,
28, 29, 31, 33, 34, 35, 36; 65 diameters. Figs. 18, 19; 80 diameters. Fig. 33; 100
diameters. Figs. 20, 25; 130 diameters. Fig. 11; 150 diameters. Figs. 4, 6; 160 dia-
meters. Fig. 21; 200 diameters. Fig. 24; 320 diameters. Fig. 22; 500 diameters.

PLATES 23 AND 24. Lepiota cristata

Fic. 1. (No. 18.) A median longitudinal section of a young basidiocarp with
fundament of stem, as darker interior area.

Fic. 2. (No. 16.) Median longitudinal section. Fundament of stem and pileus
enveloped by ground tissue, and blematogen as an external zone.

Fic. 3. (No. 5/2-1.) Median longitudinal section. Primordium of hymenophore
as two darker staining internal areas symmetrically disposed on either side above early
stage of the annular cavity appearing as two light areas. The pileus is further organized
and concrete with the blematogen, which shows as a lighter external zone.

Fic. 4. (No. 5/2.) “Longitudinal ‘‘tangential’’ section of same basidiocarp, passing
through the hymenophore primordium and annular prelamellar cavity. Note the
slender, loosely arranged hyphae of the hymenophore primordium projecting down into
the gill cavity.

Fic. 5. (No. 9/1.) Longitudinal ‘‘tangential’’ section of another basidiocarp,
just passing out from the stem. Note the densely staining sections of the hymenophore
on either side and the early stage of the gill cavity below.

Fic. 6. (No. 1-2.) Longitudinal “‘tangential’’ section of another basidiocarp pass-
ing through one side of the hymenophore primordium, which is the dark transverse
area, the slender hyphae growing down into the loose ground tissue below. The latter
is beginning to tear apart, forming a very early stage of the gill cavity.

Fic. 7. (No. 6/2-1.) Median longitudinal section of older basidiocarp. The
young lamellae are cut nearly in a parallel direction. The blematogen shows distinctly
on the right hand side over the pileus and extending down past the pileus margin and
on the outside of the partial veil proper, the latter formed of ground tissue and some
growth from pileus margin.

Fic. 8. (No. 6/1-1.) Same basidiocarp, but section slightly ‘‘tangential’’ and
through one side of the stem. Blematogen and partial veil proper, as in Fig. 7. On the
left a gill cut obliquely; on the right the section passes between two gills.

Fics. 9-12. Four longitudinal ‘‘tangential’’ sections of the same _basidiocarp
selected from a series showing origin of lamellae as downward growing salients into the
general annular gill cavity.

ATKINSON : LEPIOTA CRISTATA AND L. SEMINUDA 22.7

Fics. 13 and 14. (No. 28.) Sections of another basidiocarp, 13 median, 14 slightly
“tangential.”

Fics. 15 and 16. “Tangential” sections of the same basidiocarp.

Fic. 17. (No. 29.) Portion of median longitudinal section of a nearly mature
basidiocarp (stem at right), showing marign of pileus, which is very strongly epinastic-
Blematogen concrete with the surface of the pileus proper, showing distinctly over
margin of pileus and extending down over the ground tissue which forms the partial

veil proper between margin of the pileus and stem.

PLATES 25 AND 26. Lepiota seminuda

Fic. 18. (No. 7.) Median longitudinal section, showing primordium of stem
and pileus surrounded by ground tissue, and blematogen on the outside.

Fic. 19. (No. 10.) Median longitudinal section of a slightly older basidiocarp,
showing transsections of the hymenophore primordium on either side with beginning
general annular prelamellar cavity below. Note arched section of pileus primordium
between the transsections of hymenophore primordium, the loose ground tissue above,
and the blematogen of globular cells as an external envelope of pileus and extending
far down over the stem. The ground tissue below pileus margin and hymenophore
primordium is the fundament of the partial veil proper which is covered externally by
a section of the blematogen.

Fic. 20. (No. 19.) Longitudinal ‘tangential’? section of another basidiocarp,
passing through one side of the annular hymenophore primordium and the beginning
annular gill cavity.

Fics. 21 and 22. More highly magnified photomicrographs of the left side of
figure 19, showing hymenophore primordium in transsection, the ground tissue below,
and the blematogen outside at the left.

Fic. 23. (No. 11-1.) Median longitudinal section of a slightly older basidiocarp.
Pileus further organized; primordial stage of the hymenophore next the stem has changed
to the palisade stage, prelamellar cavity is well formed, blematogen appears as a very
distinct external layer.

Fic. 24. More highly magnified photomicrograph of the left side of figure 23
(stem axis, not shown, is at the right), palisade stage of hymenophore at right, pri-
mordial stage, and margin of pileus at left, blematogen to the extreme left, the external
portion not shown, partial veil proper between blematogen and gill cavity below pileus
margin and primordial stage of hymenophore.

Fic. 25. ‘‘Tangential’” section of same basidiocarp, passing through one side of
annular hymenophore and gill cavity. Hymenophore above cavity, palisade stage in
the middle and primordial stage on either side.

Fics. 26-31. Longitudinal median and “tangential” sections of a basidiocarp in
which the palisade stage of the hymenophore is just passing into the stage of the gill
salients. Fig. 26 shows the large prelamellar gill cavity in transsection; the stem is
well organized with an external layer of more slender hyphae richer in protoplasm which
stains dark; the blematogen has separated from the pileus here and also in figures 27
and 28. Fig. 27 ‘‘tangential”’ and a little beyond the stem. The hymenophore shows
no evidence of gill salients. Fig. 28 nearer margin of the pileus, no gill salients on this
side of the hymenophore. Figs. 29-31 are from tangential sections of the other side of
the pileus; fig. 29 is just in the surface of the stem at the angle of junction of stem and
pileus, no gill salients shown near the stem since there is a sterile zone between the
posterior ends of the gills and stem; toward the margin of the pileus in the upper part
of the arched hymenophore there is the slightest evidence of a young gill salient; fig. 30,

228 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the slight gill salient is stronger as this is farther from the stem; fig. 31, farther from
the stem and four very slight gill salients are seen, the one at the right is the same one
as shown in fig. 30, but is lower since it is nearer the margin of the pileus and younger,

Fics. 32-36. (No. 9.) Similar series of sections from a slightly older basidiocarp
in which the gill salients are better organized near the stem where they are older, suc-
cessively lower and younger toward the margin of the pileus where in figure 36 there is
but the slightest evidence of the palisade stage thrown into two salients, with the primor-
dial stage of the hymenophore shown on either side at the extreme margin of the pileus.

Fic. 38. (No. 20.) ‘‘Tangential’’ section through pileus and hymenophore about
midway between stem and margin of pileus in a nearly mature basidiocarp.

Fic. 37. (No. 17/2.) From one side of a nearly median longitudinal section of
another basidiocarp showing margin of the pileus and the blematogen to the right.
Below the margin of the pileus is the ground tissue forming the partial veil proper with
a section of the blematogen outside and concrete with it.

Mem. N. Y. Bor. GARDEN VOLUME VWI, PLATE 21

LEPIOTA CRISTATA

os
PV es ew et ap ae 44?
*

-
q ,
ae
b Sate a * >»*
Pe) an v= a. oe
oe a = :
i. : :
ra.
--4 Z ~
ay, * %
toe i
= 7 i
25 * ‘
% *
7 cs es :
25.0 pe head
_ >
as , ¥ ws
+). 2-8 Se nae Ores
a ’
Sage. hale r ba
» Oy vim
“4 * - a
i =
* 1) q . =. s
re
pee - ave
Rae. te :
— 2 $ ' > *
Po ras .
‘ :
~ ‘
*)
4 , - -
"s be ts ee z 4
*. a 3 *
=
EOY,/ Pa} , ~
ee ae :
y - ie
r< a y
to “ - -
-
tale? % 5) =a
¥ ~
er
. ohm
P = / - Y
| “3
«=
~~ = - -
bet! a > i a
a Se
J me yy =
ie ice Pa te ae ~.
= - > -
pe : a 2
~ ) me =
boy
b) J . ee " ~ 4
> . <
r -
<< ;
-- - I
' ms _¢ .
f = a ed 4
- ~ ~ >
bd -
ba ei = - xr
- us
ra a: e at tf
7,5 4
ioe 4
i"
ty. 4 = ”
.
“i < a5
° . 7
ies
& 7 _—y
Pike ¥ ee
ne ta” P =
ee a
i--
yr .
: - a4
H ~— bo . a
soars t P
bia” > & bs 2
’ ri
io -
- Peete oe.
‘ Cea a
4 7 , ’ Fie 4
“ “
2 ’ * oe as
2 bh Id a
. i) y - .
: wae * 4
« < ae ,
fine iA > 1” iy
* a4 4 Bas
h ~ S 4 it pie eg as
t: “ei be 7 7
_ ¥ han)
rt a. . ’ bed oa i
2 a is > s
re > i ~~ eos ‘
4 eee eG

F oe
+ aa

cS
oe"

* .

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 22

21-T-! bieTa Semihuda

LEPIOTA SEMINUDA

Mem. N. Y. Bor. GARDEN VOLUME VI, PLATE 23

on tae

Phe
ee) r
as

LEPIOTA CRISTATA

VOLUME VI, PLATE 24

Mem. N. Y. Bot. GARDEN

LEPIOTA CRISTATA

to
On

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE

LEPIOTA SEMINUDA

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 26

30 ~as
ay

» Fe ay R

LEPIOTA SEMINUDA

A TETRACOTYLEDONOUS RACE OF PHASEOLUS
VULGARIS

J. ARTHUR HARRIS

Station for Experimental Evolution

I. INTRODUCTORY REMARKS

The practical utility of cotyledon number in schemes of classi-
fication has been the cause of great emphasis being tacitly laid
upon the constancy and fundamental significance of this character.

The tenability of such a position has been considered by various
writers. In part this has been quite incidental to a discussion
of the homology of the cotyledon, as, for example, in the paper by
Lyon! and in some of the older morphological literature to which
reference may be obtained from papers cited below. In larger
measure the discussion has centered directly on the problem of the
origin of the monocotyledons. Sargant in 1902? and again in
1903° contributed extensive data from seedling stages to the prob-
lem. At about the same time my interest in the questions was
aroused by anomalous seedlings of Pachira of the Malvaceae’ and
in an early discussion® I outlined some of the chief problems
requiring investigation. More recently Coulter and Land® and
Coulter’ have discussed the subject upon the basis of embryo-
logical evidence.

These papers deal primarily with the problem of monocotyledony

1Lyon, M.E. The phylogeny of the cotyledon. Postelsia 1: 57-86. 1902.

2 Sargant, E. The origin of the seed-leaf in monocotyledons. New Phytologist 1:
107-113. Ig02.

3Sargant, E. A theory of the origin of the monocotyledons founded on the structure
of their seedlings. Ann. Bot. 17: I-92. pl. 1-8. 1903.

4 Harris, J. Arthur. The germination of Pachira, with a note on the names of two
species. Trans. Acad. Sci. St. Louis 13: 203-209. pl. Q-II. 1903.

5 Harris, J. Arthur. The importance of investigations of seedling stages. Science
II. 22: 184-186. 1905.

6 Coulter, J. M.,& Land, W. J. G. The origin of monocotyledony. Bot. Gaz. 57:
509-519. pl. 25-29. 1914.

7 Coulter, J. M. The origin of monocotyledony. Ann. Mo. Bot. Gard. 2: 175-183.
1915. [Illust.] i

229

230 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

and dicotyledony, although the question of the origin of cotyledons
in excess of two is not left altogether out of account.

In the literature of experimental breeding both an increase in
the number of cotyledons in dicotyledonous plants and a decrease
(in the form of syncotyledony) has been discussed, chiefly in the
universally known work of de Vries. The purpose of the present

‘ contribution to our knowledge of the subject is to give the history

and a brief characterization of an apparently fixed polycotyle-
donous:race of the common garden bean.

II. ORIGIN OF RACE

In the autumn of 1907 I secured in Athens County, southeastern
Ohio, a series of 160 individually harvested plants of this so-called
navy or white soup beans. These have been grown for various
purposes since that time in pedigreed but unguarded experimental
cultures. The history of the first four generations 1907, 1908,
1909, and 1910 has been given elsewhere,’ and many physiological
and morphological characteristics and interrelationships of this
group of plants have been expressed quantitatively in a series of
papers? dealing with this among other varieties of beans.

In 1911 a large quantity of seed from the 1909 culture grown
in southeastern Ohio was planted at Cold Spring Harbor for the
purpose of investigating certain points that have no relevancy in
this place. In the spring of 1912 the seed grown in I9II was
germinated by lines to determine the number and type of seedling
abnormalities. Altogether records of the characteristics of 238,015 _
seedlings were made. Of these 4,286 were recorded as in some
degree abnormal, and were placed (with the exception of 30 plants
which were discarded), in the field with 5,098 normals from the
same parent plants for future propagation. Nine of these ab-
normal plants—designated by their field numbers in the 1912
column of Table I—were distinguished by producing exclusively
abnormal offspring, 85 in all, in 1913. These form the recognized
beginning of the race here described.

Three of the 1912 plants produced but a single viable offspring

1 Harris, J. Arthur. A first study of the influence of the starvation of the ascendants
upon the characteristics of the descendants. Am. Nat. 46: 313-343, 656-674. f. I-II.

1912.
2 See a bibliography in Am. Jour. Bot. 1: 410-411. 1915.

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 231

seedling in 1913. Two of these died before maturity. Thus the
experiment was reduced to the progeny of seven plants none of which
have since been lost, although the death rate in germination is.
high, and a considerable proportion of the 1913 plants died before
maturity or were killed by frost.

TABLE I
eee eed ee Offspring plants aN patecnaiiee 1a Offspring plants Z ne
ber, 1912 ber, 1912 |
1913 IQI4 IgI5 1913 IQI4 IQI5
222K 38 II4 2,426 5,782 at — —
5,570 9 62 2079 7,026 12 90 1,365
5,831 5 14 106 4,434 Lap a oa
5,802 7 31 594 5,349 2 5 55
5,764 7 45 ij. || aieen| aL a LL |
Motalataa 85 260) ||)" 7,602

The seven pedigrees gave a total of 361 abnormal offspring?
in 1914 and of 7,602 in I915.°

In 1912 there was no reason to distinguish-the 9 seedlings which
gave rise to the race here under consideration from any other of
the 4,286 abnormal ones secured in the germination of the 238,015
plants. They were quite naturally described by means of the
same schedule as the other plants. Because of the great variation
in the structural characteristics of bean seedlings, the classes of
these descriptive schedules were necessarily of a very general and
comprehensive nature. Had it been possible to foresee that
these plants would be particularly interesting because of their
progeny, each one would of course have been described and
figured in detail.

According to the records of the schedule employed, only one of
the plants has a normal axis (Class I). Six were described as
slightly broadened (Class II) and two as very greatly broadened
or fasciated (Class III).

In only a single case are the cotyledons described as normal in
number and insertion. In one seedling they were unrecorded.
In four seedlings they were three and in two cases four in number.

1 Died in 1913.

2 In addition to these three were three of questionable character and seven apparently
morphologically normal plants, which will be discussed below.

3 The actual number of plants in 1915 was somewhat higher, but because of the

pressure of other experimental work in the spring the sand in the seed pans could not
be worked over for plants which had died at an early stage in germination.

232 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

In three instances there were one or more axillary shoots from the
cotyledons.

“Tn all plantlets the primordial leaves were highly abnormal in
insertion, form, or number.

In 1913 and 1914 numerous plants were available for compara-
tive study, and extensive descriptive notes were drawn up. Since,
taken as a whole, these showed the same general characteristics
as the 1915 series, which is described quantitatively below, it
seems unnecessary to present details concerning them.

As noted above, there were in the 1914 culture seven plants de-
scribed as morphologically essentially normal. Three of these had
purple hypocotyls, indicating accidental hybridization with some
variety with pigmented seed-coats. Four of these plants died,
three produced offspring. Two of these three were purple-stemmed
seedlings which produced dark-coated seeds. These were clearly
hybrids due to vicinism. The third plant, with a green hypocotyl,
produced white seeds which gave only normal plants in 1915.
Possibly this was due to the accidental introduction of a normal
seed. The line is being continued.

In 1915 there were 2 plants among the 1,202 studied in detail
which had the normal number of both cotyledons and primordial
leaves. A few other plants of the same kind occurred among the
6,400 plants which were not described so minutely. These
numerically normal plants generally have other features of leaf
form or texture which indicate that they belong to the race.
Some of these individuals will be bred further. In the meantime,
I consider them as merely the extremes of a highly variable series.
Their presence seems to me at present to qualify in no degree the
conclusion that the race is fully constant.

The first question concerning this tetracotyledonous race that
the reader would like to have decided is the nature of its origin.

While it was secured at the very beginning of a selection experi-
ment, it can not possibly be regarded as produced or built up by
selection. It was merely isolated. It wasisolated simultaneously
in seven, and probably in nine,! individuals. The records show

that all of these nine slants belong to_a single line, the produce of

plant 139 of 1907.
SSS eee eae

' The four offspring seedlings of plants 5,782 and 4,434 died without producing seed.
Their progeny could not, therefore, be adequately tested.

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 233

Concerning the structure of the seedling of the 1907 plant, or
of that of its six F; (1908) and six F, (1909) descendants, nothing
is actually known. The seeds were planted directly into the
field. Seedling characters were not studied until 1912.

It seems highly probable that these seven or nine seeds were
produced by a single plant of the 1911 culture. It does not seem
profitable to consider the various points at which the fundamental
variation may have occurred. ‘That the race originated some time
between 1907 and I9QII inclusive is clear from the fact that a
relatively normal strain of plants from the same line of plants is
at present under cultivation at the Station for Experimental
Evolution.

In the 1912 germinations, line 139 gave a total of 4,375 seed-
lings of which 4,239 were normal and 136 (including the 9 plants
the offspring of which are here considered) were abnormal. Of
the 4,375 seedlings studied in 1912 a series of 71 abnormal (exclud-
ing the g here especially under consideration) and 79 normal
individuals were grown to maturity and produced a total of 1,621
offspring seedlings in 1913. All these progenies were relatively
normal, containing a total of only 45 abnormal plants or 2.78
per cent, as compared with sensibly 100 per cent in the so-called
tetracotyledonous race.

Thus the origin of this race of plants has all the characteristics

\or a de Vriesian mutation.

III. QUANTITATIVE CHARACTERIZATION OF THE RACE

The precision of a quantitative description of the race is limited
by technical difficulties in counting in the case of the discrete
variates and by the possibility of personal equation in the case
of the characters which must be described in arbitrary categories.

Because of the pressure of other experiments and the difficulties
of classifying plants with such a high degree of abnormality the
description of the 1915 germinations of these lines was necessarily
incomplete. To have expressed adequately the characteristics of
several thousands of plants of such complexity of structure would
have required many weeks’ work, and in the present state of our
knowledge of the morphology of the bean seedling would have
been of doubtful value.

I have therefore limited myself to a detailed study of a portion
of the material only.

‘A eet

234 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

As a test of our ability to determine the characteristics con-
sistently, we classified two lots of seedlings which should within
the limits of the probable error of random sampling be the same
except for differences due to age. One of these is designated as
more mature series and the other as the less mature series. The
closeness of agreement between the constants for these two series
should furnish some measure of the accuracy with which the plants
can be classified. The results of these determinations are given
in the tables below.

Axis

The axis may be either round and slender throughout or con-
siderably broadened or even divided.

Four classes, designated by Roman numerals, have been recog-
nized: : |

I. Normal; terete, simple and slender throughout.

II. Epicotyl or sometimes both epicotyl and hypocotyl slightly
broadened or fasciated.

III. Epicotyl or both epicotyl and hypocotyl much broadened
or fasciated.

VI. Division of the epicotyl into two or more branches. This
refers exclusively to divisions occurring below primordial leaves,
not to the formation of two terminal buds beyond them, since it was
not always possible to make out this point.

In the classification of the stem much trouble was given by
axillary shoots from the cotyledons. Because of the scatter of the
cotyledons and the occasional occurrence of leaves interspersed
among the cotyledons, it was not always possible to decide whether
an apparently branched axis represented a true dichotomy or the
development of axillary buds. peice a

With respect to this character the individuals in the series are
distributed as follows:

Less mature series | More mature series Both series
Character of axis! ry a = tie
Frequency Per cent Per cent Frequency Frequency Per cent
PN ormalln. o/c 0, e052 sis go 20.93 42.88 230 al 4q2r 35.03
II. Slightly fasciated....| 206 47:91 | 18.78 °|) Ve eee 29.20
III. Greatly fasciated.... 20 4.65 4.66 | 36 | 56 4.66
VI. More or less divided 114 26.51 33.68 260 374 Site

1 The terms used are explained in greater detail in the text.

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 235

The results of the two determinations are in fair agreement
except for Classes I-and II. It is exceedingly difficult to avoid
personal equation in distinguishing between these two classes.
I attribute the wide differences in percentage frequencies to this
cause.

The fact that less than 5 per cent of the seedlings have axes
which are described as much broadened or fasciated, taken in con-
nection with the uncertainty of the division between the normal
and the slightly broadened axis, indicates that the increase in the
number of cotyledons and primordial leaves is not fundamentally
due to fasciation. It appears rather to be attributable (when any
modification of the stem is involved) to division of the axis or to
the production of axillary shoots from the cotyledons. To this
point I shall return below.

Cotyledons
While the race has been called tetracotyledonous, the number of
cotyledons is really highly variable, as is shown by the totals of .
TABLES IT and III, and graphically in DIAGRAM I.

APAN SILI; I
COTYLEDONS AND LEAVES IN LESS MATURE SERIES
Leaves

I 2 3 4 5 6 | 7 8 9 10 II 12 Totals

o| 2 —| 1 Be |) 4 a6. A I I r|/—)—|— 19

Ss 3 Sasi ae2aeesos 27) 05. | WSO ea | fom ah any

= 4 3 D7 340 | BO |) 40") 255) 23 ee oe 2) lea 233

2| 5 I I 3 Ti oy 2 I 3 I = | == 36

O| 6 a a em tl || a | htt 3

Totalsi..3)) 6) Ww20aie67- 10g 78 | 56). 41 -|\-29 | UGH eg 3 I 430

TABLE III
COTYLEDONS AND LEAVES IN MORE MATURE SERIES
Leaves

I 2 3 4 5 6 7 8 9 Io II 12 14 | Totals
a | 2 == fn 6 3 2 I 1 ered Sepa dace |W cacy are ed ea 14
Oe aS J 13 | 44) 59| 47] 21/ 13 7 4 arf Me ix, Maman esate
@| 4 An, | PSA WOO a2 78 200") 72) +32 | 24 | 13 Ov 5.4) —— fr, | S01
5: Pa eee oneMeBN 2) tog Wa ag Wea | eee logy
o| +6 = | = | I 2‘ — 2 i | 6
=) 77 a | ce ry | — S| — yr I
| Totals. 5 48 | 1341195 | 160] 102! 51 | 36 | 17 aE 7 I I 772

236 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The most of the cotyledons are large and typical in form but
occasionally those which are small and scale-like are observed.
They may be inserted in a regular whorl or widely scattered along
the axis. Nevertheless the counting of the number of cotyledons
can, I think, be carried out with reasonable accuracy.!

pelmaieste || |_| a eat ara
“65
pam |i| | |

maple sh

humber of Cotyledons

— *—* More Matvre Series

- —0=Less Natvre Series

CIS &

KR
vy
i

ge Fre

PS
—
Percents

DIAGRAM I. Frequency distribution of number of cotyledons per plant.

The tables and graphs show that in samples of the present size
the range is from two tosevencotyledons. There is a distinct mode
k ee ‘ wee r . . .
in both samples upon four cotyledons. The distributions are de-

‘In a few cases we determined the number of cotyledons from the number of scars,
but in only a few.

( rN

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 237

cidedly asymmetrical, the mode lying above the mean. There
seems no obvious advantage in fitting theoretical curves to these
observed frequency distributions, at least until wider series of data
grown under experimentally controlled conditions are available.
The variation constants for number of cotyledons are as follows.

Mean Standard deviation | Na
Less matnrs Genes... sec we ost Ss: 3.686 + .023 "| 0.716 +.017 | 19.43 + .46
Moreumature Series. ccf. 50 ce 32755 22 -O15,_|/ @.616-E .011 16.40 + .29
DEKE Geiss ee hittegs Non os heg-neeeus ead ere .069 + .028 OFLOO}=— O20) ||) 93.0292: 255
More and less mature combined..... 3.730 + .013 | .654 + .090 17.54 = .25

Thus there is an average of about three and seven tenths coty-
ledons per plant, with an absolute variation as measured by the
standard deviation of about seven tenths of a cotyledon, or seven-
teen to eighteen per cent.

The question of the relationship between the character of the
axis and the number of cotyledons can not be discussed in detail
here. The accompanying table shows the average number of
cotyledons for each type of axis.

Mean number of cotyledons

Class of axis |
Both series

Less mature series More mature series

|
iN pOrcing yal | Seleanenel anc dene eageen ra ce 3.63 3.70 3.69
MBL te chastise ear ies 3.70 3.74 | B72
a eee 3.80 3.83 | 3.82
MING re PSE See 3.68 3.82 3.78
Loe: ee 3.69 Ber 373

It is clear that there is no intimate_dependence of cotyledon
number ber upon the structure of the stem. If the comparison be
reduced to that between plants with axes normal or only slightly
broadened! and those with axes much broadened or divided, the
results are:

Average number of cotyledons
Class of axis zy
Less mature series More mature series | Both series
land TIS.) 322). Se ee eee 3.68 | Baril 3.70
Ill and(VD) idoiks neh ee ae a 3.70 3.82 3.79
Totals). 0 A.3, eee ee 3.69 | 3.76 3.73

1 The combination of these two classes seems to be necessary because of the difficulty
of distinguishing sharply between them.

238 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

These differences are very slight indeed. Such results indicate
very clearly that the increase in the number of cotyledons over
the normal which characterizes this race is not fundamentally due
to a broadening of the axis.

The accompanying table shows that about fifty per cent of the
plants are recorded as having produced shoots from the axils of
the cotyledons.

Less mature series More mature series | Both series
| Frequency) Percent | Percent Frequency | Frequency | Per cent
| }
With axillary shoots..... 227° |. 5276=") “4G.85 362 | 589 49.00
Without axillary shoots ..| 203 | 47.21 | 53.11 ALON. | Ole ah Ske ao

It is interesting to note that a higher proportion of the plants
are recorded as producing axillary shoots in the less mature series
than in the more mature series. The difference is probably due
merely to the errors of random sampling, but the fact that the
axillary shoots are not more abundant in the more mature series
indicates that they are not structures of late development.

Primordial leaves

The following conditions present real obstacles to the deter-
mination of the number of primordial leaves with a high degree of
precision.

(a) When the seedlings are very young all the primordial leaves
are not fully expanded, and there is consequently some technical
difficulty in determining the true number. (6) When the plants
have grown to a considerable size shoots are apt to have developed
from the axils of the cotyledons which by this time may have
fallen. It is exceedingly difficult, as pointed out above, to dis-
tinguish between these axillary shoots and the longitudinal or lat-
eral division of the stem. This is especially true if the cotyledons
have fallen. Since the earlier leaves on the axillary shoots are
apt to be simple, they would, if included, increase the number of
primordial leaves. (c) It seems quite probable that some of
the axillary shoots have started development during the matura-
tion of the seed. Since it is impossible to distinguish between
these axillary shoots and branches of the stem originating other-
wise, primordial leaves found on them should be counted in.

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 239

Thus there is really very great difficulty in determining which
simple leaves should be counted as belonging to the primordial
ones. What one would like to do would be to include only these
which were laid down in the seed. This we tried to do.

i ae Number of Primordial Leaves

= fore Matvre Series

o—°= Less Mature Series

DIAGRAM 2. Frequency distribution of number of primordial leaves per plant.

The distribution of the number of leaves per plant is given in
the totals of TABLES II and III and represented graphically in
DIAGRAM 2.

Inspection of the totals. of the tables shows that number of
leaves has a far wider range of variation than number of coty-
ledons. In both cases the greatest frequency falls upon four. In
both cases the distributions are decidedly asymmetrical. In the
case of the leaves, however, the mean falls above the mode—in

240 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

fact is greater than the mode by almost one unit—whereas in the
cotyledons the average was less than the modal class.
The variation constants are as follows:

Coefficient of

Mean Standard deviation | variation
Less mature series. ...\..2..,.2-2...) 4.9092 =e 005 1.991 + .046 | 39.89 + 1.05
More mature series................ 4.852 + .047 1.933 + .033 | 39.84 + 0.79
Bifierencen se. See Gar ele sie eres .139 + .080 .058 + .057 (O5¢==al-an
More and less mature combined Ey he 4.902 + .038 1.955 + .027 | 39.88 + 0.63

The samples do not differ significantly in any constant.
Comparing-the constants for number of cotyledons and leaves
on the basis of the total materials I find the following constants:

ebasteats for cotyledons' Constants for leaves Difference in constants
IMIG Eh Macc reise, s)6 3-730) a= 01g 4.902 + .038 1.172 + .040
Sy Be ae tao - cero eee (654 = 090° | Pr:gs55 =e 2027 1.301 + .094
CO ree See ee 17.54 +£0.25 | 39.88 +£0.63 | 22.34 + 0.68

Thus the mean number of leaves is about 31.4 per cent higher
than the mean number of cotyledons, the absolute variation in
leaf number is about 200 per cent greater and the relative varia-
tion as measured by the coefficient of variation is over twice as
great as in the case of cotyledon number.

The number of leaves per plant is in some degree related to
the character of the axis. Examined in the crudest manner
possible,’ by determining the average number of leaves produced
by plants with different types of axis, I find the following results:

Average number of primordial leaves

Class of axis

Less mature series More mature series Both series
Normal 4.07 4.34 4.29
De ae 4.74 4.48 4.64
WE Saar iec es te ek Vie eae 5.65 4.36 4.82
NO i Ais sor tot waste. 6.05 5.77 5.86

Thus an increase in the number of primordial leaves is associ-
ated with a broadening or division of the axis. This increase is
distinctly greater than in the case of the cotyledons.

1 With a more careful classification of the structure of the axis it will be profitable to
apply correlation formulae to the problem.

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 241

If the plants be thrown into two groups only, as was done
above in the examination of cotyledon number, the results are:

Average n umber of eeuinrorual leaves
Class of axis

Less eS series | {More mature series | Both series
I arid Te weer cece 4.54 4.39 | 4.44
Pikand\ Wate eee eee wnte 5.99 5.60 | 5.72
Ota Stee ie tars. sarees ete | 4.99 | 4.85 | 4.90

The differences are far larger than in the case of the cotyledons,
but the mean number of leaves on plants with normal or but
slightly broadened axes is so high that the results fully substantiate
the conclusions drawn above, that the approximate doubling in
the number of cotyledonary and foliar organs is not fundamentally
due to a broadening of the axis.

If the seedlings be classified without regard to the structure of
the axis into those with and those without axillary shoots, the
results show that in both less and more mature series the plants
with the axillary shoots have a higher number of primordial
leaves. Thus:

Mean leayes in plants Mean leaves in plants iff
without axillary shoots with axillary shoots Difference
Less mature series. ... 2... 4.507 + .083 5-423 + .094 .Q16 + .125
More mature series........ 4.746 + .064 4.972 + .069 .226 + .094
Mitherencenac sok, we oe -239 = .105 ight SE ay

This is quite what one would expect from the fact that the simple
leaves of axillary shoots which seemed to have developed in the
seed were counted in the number of primordial leaves. The con-
stants show, however, that the difference is not large, amounting
on the average to less than a leaf in the two series considered.

The fact that the excess in number of primordial leaves in
plants with axillary shoots is greater in the less mature than in the
more mature series, shows that there can be no considerable error
introduced by the counting of simple leaves of late development.

With respect of size, form, and structure the leaves vary enorm-
ously. They range from those which are minute to those which
are far larger than the primordial leaves of normal plants. Length,

242 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN -

breadth, and form of base and apex are extremely variable. Gen-
erally the leaves were moderately plane, but in some instances
they were highly irregular, with revolute margins.

In some, but not numerous, instances filiform filaments occupy
the positions of primordial leaves, and have been counted as such.

Monophyllous obliquely infundibuliform ascidia are abundant. ©
In the less mature series 2.42 per cent of the leaves and in the
more mature series 2.38 per cent of the leaves are thus modified.
This is extremely abundant as compared with any other strain of
Phaseolus vulgaris with which I have had experience.

The various combinations of cotyledons and primordial leaves
per seedling are shown by the double entry TABLEs II and III.
the totals of which have already served in the discussions of coty-
ledon and leaf number. Here the entries in the body of the
table show the frequency of occurrence of plants with the number
of cotyledons indicated at the left and the number of primordial
leaves designated in the upper margin.

From these tables the degree of correlation between the number
of cotyledons and the number of primordial leaves can be at once
determined. ‘The results are:

For less mature series, f = 117 = .032
For more mature series, 7” = .157 + .024
For both series combined, r = .139 + .O19

Since perfect correlation is numerically represented by a coef-
ficient of unity, it is clear that the degree of interdependence
between cotyledon number and primordial leaf number is very
slight. This result may come as something of a surprise to genet-
icists who have stated that the correlation between the two is
perfect.

The actual relationship between the two variates can be clearly
brought out by calculating equations to smooth the mean number
of cotyledons associated with different numbers of primordial
leaves and the mean number of primordial leaves associated with
different numbers of cotyledons. ‘They are:

For less mature series—

HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 243

For more mature series—
Ll = 3.004 + .492 ¢
C = 3.513 + .o501
For both series combined—
P= 3.356 + .414 ¢
¢ = 3.502 + .0461
The second term of the equation shows that for each deviation
of one cotyledon from the mean number of cotyledons there is a
deviation of about four tenths of a leaf from the mean number of
leaves. For each deviation of one leaf from the mean number
there is associated a mean deviation of only about five hundredths
of a cotyledon.
These lines are shown graphically with the empirical means
in DIAGRAM 3. ‘The agreement between the observed and the
smoothed frequencies is not very close.1
At present it seems undesirable to attempt a closer statistical
analysis of the data. Such would better be reserved until wider
and more precisely recorded series of observations on plants grown
under more closely controlled conditions are available.

IV. RECAPITULATION

The teratological race of Phaseolus vulgaris described in the
preceding pages has proved constant with exceptions which may
probably be disregarded for three offspring generations. These
comprise 85,371 and 7,602 individuals respectively. A limited
test of the fourth offspring generation has indicated perfect
constancy.

The race appeared in a ‘‘pure line’”’ of beans derived from a
single parent plant grown in 1907. It was isolated in seven and
probably in nine individuals grown in 1912 from mass culture
seed harvested in 1911. All the circumstances of its origin are
characteristic of de Vriesian mutation.

While Tetracotyledonous has been selected as the most convenient
single descriptive term, the race is differentiated from the normal

1 A part of the discrepancy is, however, apparent rather than real. Thus the aberrant
means for cotyledon number for plants with 12 and 14 leaves are based upon a single
seedling each. Plants with 6 and 7 cotyledons are but 10 of the 1,202 individuals.

The very aberrant average for leaf number associated with 6 cotyledons in the less
mature series is based upon 3 individuals only.

244 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN —

bean seedling in numerous characters. The axis may be broadened
or divided, The cotyledons are highly variable in number and
insertion. Axillary shoots from the cotyledons are abundant.
The primordial leaves are most variable in number and form.
Foliar ascidia are frequent.

BERBERS PME ee :
ecahae! rae o—=Myre Matvre Series

1s —

S
Ri
=
S
sw
a
Q
S

Sived Await ceeeee
he é a
ye Login ad caer el

DIAGRAM 3. Interrelationship of number of cotyledons and number of primordial
leaves per plant.

Both cotyledons and primordial leaves have a modal frequency
of four, but are highly variable in number. The cotyledons range
from 2 to 7 and the primordial leaves from I to 14 in the samples
studied in detail. The cotyledons have a mean number of about
3.70, with a variability of about 17.5 per cent. The primordial
leaves have a mean of about 4.90, with a variability of nearly
40.0 per cent. Thus the primordial leaves are more variable in
number than the cotyledons.

The correlation between number of cotyledons and number of
leaves is low.

JAPANESE SPECIES OF GYMNOSPORANGIUM*

FRANK D. KERN
Pennsylvania State College

Several years ago, while preparing an account of all the known
species of Gymnosporangium,' the writer’s attention was especially
attracted to the species reported from Japan. It did not seem at
all likely that the specimens and meager culture data then available
from that country adequately represented the genus as it probably
existed there. Since that time the publication of several new
species, based upon Japanese material, together with some addi-
tional culture data has materially added to our information.
Mycologists and plant pathologists in America also have an in-
terest in these forms because of the fact that they are likely to
be introduced into this country on nursery stock, such instances
having already occurred.”

The best-known Japanese species is G. japonicum described by
Sydow in 1899 [Hedwigia 38: 141(Beibl.)]._ This appears on gradual
fusiform enlargements of the stems of Juniperus chinensis. In
1900 M. Shirai reported successful cultures between this form and
Roestelia koreaensis on Pyrus sinensis (Zeitschr. Pflanzenkr. 10: 1)-
The correctness of this cultural result has not been questioned
by the various writers who have had occasion to refer to it,
until the recent work of Ito (Tokyo Bot. Mag. 27: 221. 1913).
This investigator in May, 1913, made cultures from a stem-
inhabiting form on Juniperus chinensis, which was without doubt
G. japonicum, on Pyrus sinensis, P. Malus, Amelanchier astatica,
and Pourthiaea villosa. If this were related to Roestelia koreaensts,
which was described on Pyrus sp., positive results should have
been expected upon one or both of the species of Pyrus, but such

* Contributions from the Department of Botany, Pennsylvania State College, No. 7.

1 Part II. A biologic and taxonomic study of the genus Gymnosporangium. Bull.
N. Y. Bot. Garden 7: 424-476. IgII.

2 Clinton, G. P. Ann. Rep. Conn. Agr. Exp. Sta. 1912: 350. 1913. Kern, F. D.
Loc. cit., p. 461. Jackson, H.S. Jour. Agr. Research 5: 1003-1009. I916.

245

246 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

was not the case. After seventeen days yellow spots were ob-
served upon the Pourthiaea and in five weeks aecia had developed,
while the other three species remained uninfected. While at
first this seems to be at variance with the previous results of
Shirai, it is comparatively easy to trace out the error in the work
of the latter. He had present on his culture material both a
stem and a leaf form. It can be said now without doubt that the
leaf-inhabiting form was responsible for his culture on Pyrus
sinensis. Not appreciating the possibility that he was dealing
with two species, a misinterpretation of his results was a very
natural outcome. The Roestelia produced on Pourthiaea by Ito
is undoubtedly the one which was described by Henning in 1894
as R. Photiniae (Hedwigia 33: 231) and later referred to Gymno-
sporangium by the writer (Kern, loc. cit. 443). Accordingly,
G. japonicum, the stem form, is to be considered genetically re-
lated to R. Photiniae and not to R. koreaensis. In 1912, Sydow
described an aecial stage on Cydonia vulgaris from Japan as G.
spiniferum (Ann. Myc. 10: 78). It seems likely in the absence
of cultures that this should be regarded as a synonym of G. Pho-
tiniae. The small pale aeciospores agree perfectly. The peridial
cells agree well as to size and thickness of walls; the spines may
be somewhat coarser and longer in G. spiniferum but they do
not differ essentially. The peridium is longer and more robust in
G. Photiniae on Pourthiaea but none of the species which occur on
the leaves of Cydonia seem to be as robust on it as on the other
hosts. This is very noticeable in G. Nidus-avis, a North American
species, which occurs on Amelanchier and Cydonia. The revised
synonomy and host list for this species would now be as follows:

GYMNOSPORANGIUM PHOTINIAE (P. Henn.) Kern, Bull. N. Y. Bot.
Garden 7: 443. I9QII
Roestelia Photiniae P. Henn. Hedwigia 33: 231. 1894.
Gymnosporangium japonicum Sydow, Hedwigia 38: 141 (Beibl.).
1899.
Gymnosporangium spiniferum Sydow, Ann. Myc. 10: 78. 1912.
I. Aecia, with spiniferous peridial cells, on Cydonia vulgaris (L.)
Pers. and Pourthiaea villosa (Thunb.) Dec. (Photinia villosa Dec.,
Photinia laevis DC..).
III. Telia, with spores 48-66 » long, on the woody twigs and
branches of Juniperus chinensis L.

KERN: JAPANESE SPECIES OF GYMNOSPORANGIUM 247

The suggestion in the foregoing paragraph that a leaf-inhabiting
form on J. chinensis was responsible for Shirai’s culture on Pyrus
sinensis makes it necessary to dispose of that form in some way.
When the writer prepared his monograph there were no Japanese
species described on the leaves or green branches of Juniperus
with the possible exception of G. asiaticum Miyabe (Bot. Mag.
Tokyo 17: 34. 1903). This was described in the Japanese
language and so far as the writer could make out was not suf-
ficiently characterized to establish the name. It carries with it
the information that the Gymnosporangium is on the leaves of
Juniperus chinensis, Pyrus sinensis, and Cydonia vulgaris. So
far as the general nature of the telia and the aecial connections
are concerned, the observations of Miyabe and the work of Shirai
agree. This situation is further strengthened by culture work of
Hara in 1913 (Bot. Mag. Tokyo 27: 348). There seems little
doub¢ that. the aecia with which we are dealing here are all refer-
able to R. koreaensis P. Henn. As to the identity of the telial
phase and a proper name for it, the solution is notsoeasy. If we
regard G. asiaticum as a hyponym we find the next name which
has been proposed for a leaf-inhabiting Japanese form is G.
Haraeanum (Sydow (Ann. Myc. 10: 405. 1912). In the original
publication, Sydow made no mention of an aecial connection but
in a very clear and comprehensive review of the whole matter
Ito (Bot. Mag. Tokyo 28: 220-223) has shown that the leaf forms
described by Shirai, Hara, and Sydow are identical and without
doubt belong with R. koreaensis on Pyrus sinensis. In 1914
Long! founded a* new species, Gymnosporangium chinense, on
specimens of Juniperus chinensis which were imported from Japan
by the Elm City Nursery, Westville, Connecticut, and which were
brought to the attention of mycologists and pathologists by
Clinton. This same importation of junipers had on them a stem
form which has been identified without doubt as G. Photiniae
(G. japonicum). Long recognized that this new species on the
leaves and green twigs of Juniperus chinensis was very closely
related to G. Haraeanum on the same host and originally from the
same general locality. He concluded, however, that the two were
distinct, stating that ‘‘they differ in certain fundamental micro-
scopic characters.’”’ The chief difference which he points out is
the position of the germ pores in the colorless thin-walled telio-

1Long, W. H. Jour. Agr. Research 1: 354. 1914.

248 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

spores. Clinton! in a later discussion fails to find the difference
in the location of the pores and on the whole ‘‘sees no real reason
for considering Long’s species as distinct.”” After an examination
of the specimens and a consideration of the whole matter the writer
agrees with Clinton that the grounds are insufficient for the
separation of a new species according to Long. The writer would
further disagree with Long’s intimation that a character such as
the location of germ pores in the colorless thin-walled teliospores
is a fundamental character. If one were attempting to draw a
fine distinction between the specimens from Japan and those
collected in Connecticut the presence of large numbers of thick-
walled (2.5-3 uw) teliospores in the former as compared with one
moderately thick-walled (1-1.5 uw) in the latter is more noticeable
than any other point. This is probably due to the fact that the ©
Connecticut specimens are somewhat less mature. It has been
known for a long time that the same telial sorus in the genus
Gymnosporangium may contain two sorts of spores, thick-walled
ones and lighter colored thinner-walled ones. Long has attempted
to establish a third type intermediate between the two extremes.
This simply supports the idea that the thick- and thin-walled
spores do not represent two types but simply two extremes with
gradations existing between them. Referring again to the germ-
pores, it may be said that their location in the teliospores of this
genus is variable. There is a marked tendency for the pores in
both cells of two-celled spores to be near the septum but in the
uppermost cell there may be one at the apex with or without any
at or near the septum. It is entirely probable that the thinner-
walled spores may have a tendency toward terminal pores in the
apical cell when the thick-walled spores may show the usual
arrangement at the septum. It seems improbable that such a
tendency could be sufficiently marked to use it even as a minor
specific character. Accordingly, the full synonymy for the form
on the leaves and green stems of Juniperus chinensis would be as
follows:

GYMNOSPORANGIUM KOREAENSE (P. Henn.) Jackson, Jour. Agr.
Research 5: 1006. 1916.
Roestelia koreaensis P. Henn. Warb. Monsunia 1: 5. 1900.

1Clinton, G. P. Ann. Rep. Conn. Agr. Exp. Sta. for 1914 (Report of the Botanist
for 1913): 15, 16. I914.

KERN: JAPANESE SPECIES OF GYMNOSPORANGIUM 249

Tremella koreaensis Arth. Proc. Indiana Acad. Sci. 1900: 136.
Igo.

Gymnosporangium asiaticum Miyabe, Bot. Mag. Tokyo 177: 34.
1903. [Hyponym]

Gymnosporangium Haraeanum Sydow; H. & P. Sydow, Ann. Myc.
1:0: 405. 9x2.

Gymnosporangium chinense [‘‘ts’’| Long, Jour. Agr. Research 1:
354. 1914.
I. Aecia with rugose peridial cells, on Cydonia vulgaris (L.)

Pers., Cydonia japonica (Thunb.) Pers., and Pyrus sinensis Lindl.

III. Telia with spores 35-50 u long, on the leaves and green
twigs of Juniperus chinensis L.

Ito in the paper already cited remarks that if we accept names
according to priority G. japonicum would become G. Photiniae
and G. Haraeanum would be changed to G. koreaense. He states,
however, that he is retaining the old names. An interesting
problem in nomenclature is presented by such provisional trans-
fers. There are other similar cases on record.

In the account of the genus Gymnosporangium in the North
American Flora, vol. 7, the species G. japonicum was included as
no. 21, p. 201, and the error of associating R. koreaensis was
continued there. The species was included because it was known
to have been imported into America.!. Every effort was made to
stamp it out and it probably did not become established. There
is the same basis for including G. koreaense in such a descriptive
account.2 It should be inserted among the forms appearing on
leaves or leafy twigs. It might well follow G. fraternum, from
which it could be separated by the teliospores being not or only
occasionally thickened at the apex, whereas they are uniformly
thicker above in G. fraternum.

Having determined that there is a caulicolous form, G. Pho-
tiniae, on Juniperus chinensis with aecia on Pourthiaea and
Cydonia, and a foliicolous form, G. koreaense, on the same host

1Since this paper was prepared two other importations of this species have come to
the attention of the writer, one collected by F. N. Rhodes, Seattle, Washington, im-
ported from Yokohama, Japan, the other collected by J. W. Hotson on the campus of
the University of Washington, Seattle, Wash., both in May, 1915.

2 Recently (Feb. 28, 1916) Professor H. S. Jackson has reported in the Journal of
Agricultural Research (5: 1003-1009) the complete establishment of this species in
Oregon, and has referred to incomplete evidence of its establishment in California.

250 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

with aecia on Pyrus and Cydonia, we apparently have not yet
exhausted the possibilities with regard to Juniperus chinensis.
There appears to be another caulicolous form on this host which
is connected with aecia on various species of Malus, viz. Gymno-
sporangium Yamadae Miyabe. Miyabe uses this name in a
Japanese report of the Sapparo Botanical Society (Bot. Mag.
Tokyo 17°: 34). With some assistance the writer makes out that
this occurs on the ‘‘stout part” of the stem of Juniperus chinensis
with aecia on the leaves of Malus (Pyrus) Malus, Malus (Pyrus)
spectabilis, and Malus (Pyrus) Toringo. Through the kindness of
Dr. H. Sydow the writer has secured a specimen of the aecia on
Malus spectabilis. The peridial cells are verruculose with small
oval papillae, being quite unlike the spiniferous ones of G. Photiniae
or the rugose ones of G. koreaense. The chestnut-brown aecio-
spores are also very unlike the yellow ones of R. Photiniae, which
without doubt belongs to a caulicolous form on J. chinensis.
Believing that the Roestelia represented a good species the writer
used the name G. Yamadae, in his monographic account (Bull.
N. Y. Bot. Garden 7: 446. 1911), giving credit to Miyabe.
A full description of the aecial stage was given but the telia were
said to be unknown. To that we can now add what should have
been included then, that the telia are said to be on the stems of
Juniperus chinensis but that is all the information which we have.

Pourthiaea villosa also has another aecial stage upon it which
is extremely interesting. This one is not Roestelia-like but has
short cupulate peridia. In structure and habit this form which
Sydow named Aecidium Pourthiaeae is so much like the North
American species, G. Blasdaleanum, that the writer has tenta-
tively referred it to that species. Our G. Blasdaleanum, which
is coming to be of considerable importance,! has been culturally
connected to a telial form on the incense cedar, Heyderia decurrens
(generally referred to as Libocedrus decurrens). While there has
been no report from Japan of a similar telial form, and even
though Heyderia decurrens does not occur there, the fact that

1See Jackson, H. S. A new pomaceous rust of economic importance, Gymnospor-
angium Blasdaleanum. Phytopathology 4: 261-270. 1914. And O’Gara, P. J. The
Pacific Coast cedar rust of the apple, pear, quince and related pome fruits caused by
Gymnosporangium Blasdaleanum. Tech. Bull. No. 2, Office of Pathologist and Local
U.S. Weather Bureau Station for Rogue River Valley, 1913.

KERN: JAPANESE SPECIES OF GYMNOSPORANGIUM 251

another species of Heyderta is known in the Orient makes the
suggestion worthy of consideration. Altogether there have been
three aecidioid aecia described on pomaceous hosts. These are
interesting because the host relation calls for a Gymnosporangium
connection, whereas the structure would not appear to do since
most Gymnosporangium species produce roestelioid aecia. There
can, however, be no question about the connection of G. Blas-
daleanum, which possibly includes the Japanese form, with
aecidioid forms on various Pomaceae. The third form is Aeczdium
Sorbt Arth., from the northern Pacific Coast region of North
America. Several years ago the writer! predicted the relationship
of this with Uredo nootkatensis Trelease on Chamaecyparts nootka-
tensis. At that time such a prediction was quite novel since it
was not certain that the Uredo nootkatensis represented a Gymno-
sporangium. Since that time Arthur? has reported the discovery
of telia in this form.

There is also additional field evidence that it is related to
Aecidium Sorbt as predicted. This is an especially interesting
species since it is the only one in which uredinia are known to
occur. It is suggested that the additional spore-stage, together
with cupulate aecia and foliicolous telia, may indicate a primitive
condition of this type of rust. Species occurring on the branches
producing fusiform swellings or gall-like outgrowths and related
to aecia with peridia grown out in a roestelioid fashion would be
later and more specialized developments. In connection with
such developments repeating (uredinial) stages have dropped out
of the life-cycle according to such a view.

Reference has been found to only one other species of Gymno-
sporangium from Japan. Its standing or nomenclature appar-
ently has not become involved and a brief mention will be suf-
ficient. The first reference is to the occurrence of aecia on Pyrus
Miyaber by Miyabe in 1903 (Bot. Mag. Tokyo 17?: 35). He used
the name Roestelia solitaria but so far as I am able to interpret
there was not sufficient description to establish this name. Dietel
in the same year proposed the name R. solenoides. Several

1 Prediction of relationships among some parasitic fungi. Science II. 31: 833.
1910.

2 A Gymnosporangium with repeating spores. Phytopathology 4: 408. 1914 (ab-
stract). Am. Jour. Bot. 3: 40-46. 1916.

252 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

years later Yamada and Miyabe! reported successful cultures
showing the relationship between this Roestelia and a caulicolous
telial form on Chamaecyparis pisifera, to which they applied
the name Gymnosporangium Miyabei. If we accept the oldest
valid name even though it was first applied to the aecial stage, the
name of the species is Gymnosporangium solenoides (Diet.) Kern,
(Bull. N. Y. Bot. Gard. 7: 450. 1911). The aecial hosts belong
to the genus Sorbus. Aside from Pyrus Miyabet Sarg., which
is the same as Sorbus alnifolia K. Koch, Sorbus Aria Crantz also
is reported as a host.

1 Eine neue Gymnosporangiumart. Bot. Mag. Tokyo 32: 21-28. 1908.

CYTOKINESIS OF THE POLLEN-MOTHER-CELLS
OF CERTAIN DICOTYLEDONS

CLIFFORD HARRISON FARR

Columbia University
(WITH PLATES 27-29)

1. TABLE COR. CONTENTS

Ere MAMIE COMLENES™ cn 2 wie Aa see MN ee ca Se err ees Ae ky ak Bk O53
PARE View, Gite HiteL@eliress) s O8 A erate Akt ue G GN But chat Phe hehe al, 253
GC nibivisioiy Dy GOlniml ates & kek i omit ee alk Ae A ao Oh ie Ms Nt ee sags 253

Dee vlommesisng Ge alG AG.) .0: saga RAen a Ale echo eee eh ee Se eS 8 tm 258

Gt CORO SIMeSIS ip GMe AULD has... ane eRe se ae eee ee) ECR 260

CIC ViGkinests inthe amimials, Jie aye eee hs ake LUE LER Ae ah eyes 261

EPH eOries (Oreo ll=GiVIStO Mss. os srs NLR See sloay aa oct a day Ga eaes bik caches 263

fe Lermunclary Of CelladiviSlON . .. 2c eeeMe Aor Giese La es wks 8h cdal's 264

7. QUAdripaLuicion in erymlOwaIms. <a cee tse allt ee ete oa ew A DA eens 265

ba Oviadripaiiition invgyimnes perinsi mest ee x ale wee Potkre He AAR Ee, Oo oc 268

4,, Polten-tormation inimonocotyledonsx rhs.) cs os si alagwns macd ou neee 269

PU Oulen=tor mation i GicOtyledOns.. sweees «ganic als eee ook Ae od Bre

DE iver cha) MMCEDOOS: /iteihG cs cack « ape sana ant eM teala ramet cee, aa, is ws 284
[Ve Observations on living mother-cells. | s..c. fees aoe dc) Pe hawt s eee eo 285
MlSeuMGNICM lens eat et taka’ See SS tart Ne ton eae hte 285

IEEE Go ARR RY- op eon RRR EMME CBI a 5 Sor Retort OF ets CHa ee eee 285

INTC Otiamaetc tema git neeere tone sx ser op RRR es ee peck ace eed ena nerete yeas a os 285

V.. Thickening of the mother-walls in Nicotang.. 0 5..2.0000 0. nee bee ees 290
Vic ihe centrabsoindles imiNiseiend ... REL ober ede aa 293
VII. Constriction furrows and nuclear migration in Nécotiana.................. 295
Wn Other dicatyledums <i. oe ees. .t sy Terie ae cay nina Path ast ilagiia's wood 301
Pe POISE ONIGIT aon eaters arate rain Oke CA COA mee nas ee, ke eB 303

Similarity of animals and plants in cell-division.
Quadripartition in dicotyledons, monocotyledons, etc.
Conclusions based upon literature.
Possibility of electrically charged cell-membranes.
The mother-wall and cell-division.
An hypothesis as to the physical chemistry of cell-plates.
BOMB eEAEMOR GIL CUA Se ice Read LE SRE Lit et he kh Bhs koa 'n ead soe BN 318

II. REVIEW OF THE LITERATURE
a. Division by cell-plate

Since the notable observations of Strasburger (67a) in 1875
on the existence of the so-called cell-plate as a stage in the cyto-
, 253

254 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

kinesis of higher plants, the assumption has become general that
such a structure is universally present in angiosperms, gymno-
sperms, ferns, and bryophytes. Strasburger already in 1875 dis-
cussed the formation of the plate by fusion of thickenings on the
central spindle-fibers, its splitting to form the boundaries of the
daughter-cells, and the secretion of the cellulose wall or walls
between the new daughter-cell boundaries. Strasburger’s views
have been critically confirmed and enlarged by Treub for the
orchids, Mottier for the mother-cells of the lily, Hof for the root-
tips of Ephedra, Pteris, and Vicia, Nemec for Allium, and Timber-
lake for the root-tips of Allium and for the pollen mother-cells of
the larch. In addition to this critical work there has appeared
in the literature a vast number of more or less casual statements
corroborating this interpretation with regard to the cells of
various representatives of nearly all groups of the higher plants.
Apparently in only one instance has a serious attempt been made
to question the universal occurrence of cell-plate formation in
the cytokinesis of higher plants, namely, the work of Baranetsky
(4) in 1880 which has not been recognized as presenting such an
exception to this rule, doubtless chiefly because it does not
furnish the positive proof of how division may be accomplished
without a cell-plate.

On the other hand, it has been just as carefully established that
the animal cell divides without the formation of a cell-plate in the
equator of the central spindle. Flemming’s attempt to homologize
the ‘‘zwischenkorper”’ of certain animal cells with the cell-plate
of plants has not been generally accepted. The ‘‘zwischenkorper”’
has not been shown to play any part in the formation of the new
plasma membranes, whereas this is recognized as a large part of
the function and activity of the cell-plate.

Treub (75a) in 1878 presented the first careful observations of
cell-division in living material. His findings, in general, agree
with those of Strasburger; but in Epipactis, he reports, the daugh-
ter nuclei travel from one side of the cel to the other, while the
-cell-plate is being laid down progressively between them. He
believed, however, that the cell-plate was of cytoplasmic origin.

In 1887 Went (79) for the first time presented the idea that the
fibers in the center of the spindle disappear during the growth of
the cell-plate. Mottier (44a) in 1897 confirmed Strasburger’s ob-

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 255
servations, using as material the mother-cells of Lilium fixed in
Flemming’s solutions and stained with the safranin, gentian-violet,
and orange G combination. It must be remembered that Stras-
burger’s initial work was done on alcoholic material. Mottier
studied the process following the heterotypic nuclear division and
found that there is ‘‘eine auffallende Verdickung der Faden”’ in
the equatorial region. The mother-cell-wall is shown in his figures
to thicken meanwhile to about one twentieth of the diameter of
the cell. Strasburger (67g), from his study of Lzlium and Alstroe-
meria, found that it is the fibers in the center of the spindle in
which the equatorial swellings first occur. The elements com-
posing the plate are pulled out and become extremely thin in the
middle; and as soon as they break a middle layer appears between
them. These equatorial swellings he had (67f) previously desig-
nated by the name, ‘“Dermatosomen”’; but this term has not
been extensively used since then. Hof (30) in 1898 stated that
the cell-plate formation is accompanied by the shortening of the
fibers of the central spindle, but showed no drawings to support
this view. Wager (78) more recently has figured cell-plates in
the root-tips of Phaseolus. Davis (11) concluded that the fibers
involved in the formation of the cell-plates of the spore-mother-
cells of Anthoceros are not those of the central spindle which re-
mained from karyokinesis; but that they are newly organized in
the cytoplasm after the disappearance of the latter. Mottier (440)
in 1900 modified his former opinion as to the origin of the cell-plate
in Lilium,-and after a study of Dictyota makes the following state-
ment: ‘‘ That the cell-plate in the higher plants is formed by a lateral
union or fusion of the thickened connecting fibers may be seriously
questioned, for in some cases these fibers do not thicken very appre-
ciably in the equatorial region, nor do they lie sufficiently close to
one another to enable the slightly thickened middle parts to meet
and fuse . . . the conclusion seems justifiable, that the cell-plate is
formed by a homogeneous plasma which is conveyed to the cell-
plate region and deposited there by the connecting fibers.” He
presents no new drawings of Lilium in support of this interpretation.

The most extensive and satisfactory study of cell-plate forma-
tion in the higher plants in recent years is that of Timberlake
(73) on the pollen-mother-cells of the larch and the root-tips of
the onion. The author found that the two types of cells are very

256 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

similar in their procedure in cell-plate formation; he notes, how-
ever, a number of differences which evidently seemed to him of
minor importance, but in the light of the following discussion ap-
pear to be by no means insignificant. His drawings and photo-
graphs present the only adequate attempt since Strasburger’s
“Zellbildung und Zelltheilung”’ to arrange a sequence of stages in
the formation of the cell-plate. The figures of cell-plates by others
are mostly isolated and introduced merely incidentally.

In the onion root-tip Timberlake describes the process in less
detail than in Larix. He believes that new connecting fibers are
formed at the periphery of the spindle, both in the early stages of
spindle enlargement and during cell-plate formation. Except for
the violet-stained fibers the cytoplasm is homogeneous and with-
out granules. The first indication of equatorial differentiation
is in the appearance of an orange-staining zone in that region.
With the triple stain this zone stains like the young cell-wall,
but it does not take ruthenium red or iron-haematoxylin, so that
it is probably of different constitution, though Timberlake be-
lieves it is of carbohydrate nature. : He likens it to the orange
zone in Saprolegnia, and the neutral zone in Fucus. ‘The spindle
fibers become apparently thinner in this orange zone, prior to the
appearance of the cell-plate elements, which the writer describes
as ‘‘thickenings of the spindle-fibers”’ or ‘swelling on the fiber.”’
He is unable to find evidence of any movement of cytoplasmic
granules toward the equator to form the cell-plate, as suggested
by Treub. The cell-plate elements are found sometimes to
appear before re-organization of the daughter nuclei.

In the larch the central spindle-fibers are found not to multiply
by longitudinal division in the early stages of spindle enlarge-
ment, as Strasburger holds. But their apparent increase in
number is due to their separation, after being aggregated in
bundles by pressure of the chromosomes as they move to the poles.
The equatorial thickenings on the fibers are much more pro-
nounced than in the onion root-tip. In addition to them there
are granules which are blue with Flemming’s triple stain, and are
variously distributed within the cell during the anaphases and
telophases, sometimes ‘‘in rows and sometimes sticking to the
connecting fibers.”’ The central spindle-fibers at first thicken
near the nuclei, giving the same appearance as the fibers of the

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS hy

onion, which are attenuated at the equator. The fibers of the
larch then become of uniform diameter, and lastly thicken at the
equator, giving rise to swellings. The process continues until
the fibers begin to disappear near the nuclei, that is, shorten.
“All of the fibers that form cell-plate elements are completely
used up in the growth of the cell-plate.” The swellings enlarge,
come in contact, and fuse. They do not split before fusing. The
central spindle grows peripherally, that is, centrifugally by the
addition of fibers. The cell-plate splits in the center and the new
wall is secreted (fig. 21). There are thus three processes going
on: cell-plate formation, plasma membrane formation, and wall
formation. In the larch they are all shown to take place centrif-
ugally, and Strasburger (67a) figured the same condition in
Anthericum after the heterotypic division. Timberlake believes
that the wall formation may occur by the secretion of an unstain-
able solution, perhaps a carbohydrate, between the two plasma
membranes. The phenomenon of the separation of the two
plasma membranes is discussed in some detail. Of the process
he says: “It is hard to conceive of a layer of protoplasm becoming
differentiated into two separate layers similar in all apparent
respects to each other.”

Studies in physical chemistry since the date of Timberlake’s
paper, especially in the behavior of colloids, should throw con- }
siderable light upon these processes of cell-division. The well-|
known fact of the crystalloid nature of cell-walls and starch grains
made it seem likely that the cell-plate is not of this nature, but
is more probably colloidal; and its being visible, both in living |
and fixed material, would indicate that it is probably a suspensoid.
Though probably colloidal, it is not very different either physi-
cally or chemically from the rest of the cytoplasm, or a surface |
boundary would form between them, such as delimits the nucleus;
in other words, the cell-plate differs from the plasma membranes
to which it gives rise, in that it is apparently permeable to sub-
stances in the cytoplasm indiscriminately.

A number of interesting variations from the typical procedure
are noted by Timberlake in larch. ‘‘Whether the mother-cell
divides into four cells which form the pollen grains by successive
or simultaneous division depends upon the number of spindle-
fibers existing in connection with the first nuclear division. If

258 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

there are enough fibers to form a cell-plate completely across the
cell, successive division results; while if the cell-plate does not
reach across the cell it is absorbed into the rest of the protoplasm
and the final division takes place simultaneously after the second
nuclear division.”” As noted later, Juel (35a) and Tangl (70)
have found similar incipient cell-plates in the pollen mother-cells
of Hemerocallis. Though, in the latter, they may not extend
from one side of the mother-cell to the other, they seem to reach
a condition of maturity as far as they do develop, and remain
suspended in the cytoplasm, not being absorbed, as Timberlake
reports for the larch.

b. Cytokinesis tn the algae

The algae display a considerable range of variation in their
method of cell-division. Strasburger was disposed to regard a
number of them as having cell-division by means of a cell-plate;
but the evidence, so far presented, is by no means conclusive that
the division is as it has been found in the higher plants. However,
McAllister (45) in his study of so simple a form as Tetraspora
found a great similarity to the typical seed-plant habit of division.

The cytokinesis of Oedogonium has been much studied but
without clear results. Strasburger (67a) claims that after the
nucleus divides in the center of the cell, something like a cell-
plate, consisting among other things of a series of black dots is
formed. Tuttle (77) and Wisselingh (83) have since confirmed
Strasburger’s observations as to the presence of an equatorial
differentiation between the daughter nuclei. In the cell-division
of Spirogyra there exists a somewhat greater departure from the
cell-plate type. Strasburger (67a) early described the centripetal
development of a cross-wall in the form of a girdle at the equator
of the cylindrical cell. The girdle grows by the deposition of
material on its inner edge where starch granules accumulate. The
existence of true central spindle fibers running between the two
daughter nuclei is still doubtful. In Cladophora we have an in-
stance of division of a multinucleate cell without even the sem-
blance of a cell-plate. This was first observed by von Mohl (43a)
in his famous pioneer work upon the origin of the cell. In 1854
Pringsheim (53) reported the finding of a thin division wall before
the centripetal ingrowth is completed; but about twenty years

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 259

later Strasburger (67a) worked out the details more carefully.
There is a ring-like girdle of cell-wall material which grows cen-
tripetally across the middle of thecell. Asin Spirogyra the ring is
margined by a circle of dense protoplasm. In Ulothrix the same
author (67a) presents an example of a uninucleate cell which after
karyokinesis forms its cross wall entirely centripetally. There is -
no doubt an excellent field for research on the cell-division of these
filamentous green algae.

In the brown algae several instances have been reported of a
division of the protoplast simultaneously across the equator of
the cell. This perhaps should not be taken to mean that the cell-
division takes place suddenly, but rather that at any one moment
the process is at the same stage of development in all parts of the
equatorial plane. Strasburger (67k) and more recently Swingle
(68) have investigated the process in Sphacelaria. Swingle finds
that cell-division is first indicated by the transverse arrangement
of the alveoli in the equatorial plane between the daughter nuclei.
A number of granules may appear in this region, and presently a
fine line is noticed forming a bridge across the entire cell, or some-
times only across a part. A cellulose wall then appears. The
author is unable to relate this to the spindle fibers which are con-
sidered insufficient in number, and do not multiply during the
processes just described. It is concluded that the process is not
dependent upon the activity of the kinoplasm, but, nevertheless,
may be under the control of the nuclei.

Mottier (446) found a similar manner of cell-division in Dictyota.
Neither Swingle nor Mottier present in figures any stages in the
development of the partition. They each give one figure, and
supplement this by description. While the latter is valuable, it
cannot replace an accurate reproduction of the evidence at hand.
Until some one presents an adequate series of stages of the process
we must continue to regard their evidence as not entirely con-
vincing. In fact it may even be questioned as to whether we
should apply the term cell-plate to these various sorts of forma- .
tions in the lower plants; it seems desirable rather to restrict
the term to that perfectly definite sort of structure that Timber-
lake and others have described, and which seems to be so prevalent
in the higher plants.

Farmer and Williams (18a + 6) have studied the division of

260 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the protoplasm in the oogonia of Fucus, where there are eight
nuclei, each of which becomes separated at the same time from
the others by plasma membranes; that is, there are no divisions
of the cytoplasm during the three preceding nuclear divisions.
They describe the process as beginning by the elongation of the
eight nuclei and the development of polar radiations. The divi-
sion planes themselves are marked by the accumulation of granules
which are repelled equally from all nuclei. These granules fuse
into plates which divide the protoplast into its eight respective
parts. The authors refer to the process as due to a repulsion of
material from the nuclei, but it may as well be considered an ordi-
nary diffusion of material away from the nuclei. Itis then essenti-
ally like the cell-plate formation in higher plants, except that a
central spindle is absent. It will be noted that this is also an
instance of simultaneous partition as in Sphacelaria and Dictyota.

Fucus is not the only alga in which the division of a protoplast into
more than two parts has been studied. Strasburger (67a) noticed
the quadripartition of the zygospore of Craterospermum |Mougeotia],
by ring-shaped primordia of the cross-walls, that is, by infolding and
constriction in a centripetal manner. A more lucid description
was given by Berthold (6) in 1886 of tetraspore formation in the
red alga, Chylocladia. Here we have the partition into four
spores which are tetrahedrally arranged by ‘“‘sechs dement-
sprechend orientirte Membranleisten welche, wie bei Spirogyra,
allmahlich von der Zellperipherie nach innen vordringen.’’ No
cell-plate is involved in the process. Unfortunately no figures of
the cells in division are given.

c. Cytokinesis in the fungi.

Division by cleavage furrows without the formation of a cell-
plate is the common method among the fungi, as Harper has
shown in many forms. There is the simple bipartition of a
two-nucleate cell, as in the conidiophores of the Erysipheae (28a)
the more complex “ progressive cleavage’’ of the multinucleate spor-
anges, and also of the Mucorineae, etc. (28c). Careful study and
search has revealed no evidence of the formation of a partition
plane or cell-plate in advance of the cleavage furrow, the only differ-
entiation which takes place, being in certain cases the appearance
of a clearer hyaline zone, instead of a dense protoplasm, just in

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 261

front of the furrow. In the case of Synchytrium, Harper (28c)
suggests that there are two processes involved in cleavage. ‘‘If
in Synchytrium the nuclei are centers for the formation of kino-
plasm, and it proceeds outward from them by diffusion in all
directions till it reaches the plasma membrane; this will be corre-
spondingly increased in thickness, and if the mass be decreasing
in volume by loss of water and tending to split up like a mass of
drying starch, the membrane might perhaps press into the furrows
thus formed, so as to become the surface layer of the forming
segments.”

In the Myxomycetes (28f), Harper finds further evidence of the
correlation of loss of water with cell-division. In Didymium cell-
division is accompanied by an extrusion of cell-sap, ‘‘which is
initiated and controlled by changes in the spore-plasm.”’ The
writer suggests that “If we add to this conception of the nucleus
as a center of water retention the further conception, suggested
by its relation to cell-plate formation in the higher plants and the
ascus, that it is a center for the production of plasma membrane
materials, we have two factors which would work in harmony to
bring about the process of progressive cleavage described, since
the diffusion outward from the nucleus of substances to be used
in forming the plasma membrane would again tend to cause the
cleavage planes to pass midway between any given pair of nuclei.”
In his work on Fuligo (28d) the same author found that while
the cleavage furrows cut midway between two nuclei, the process
has no relation to the orientation of the preceding nuclear division
figures.

d. Cytokinesis in animals

In the animal kingdom there is considerable variation in the
process of cytokinesis, though it hardly displays as wide a range
of types as the plant kingdom. In the typical case the cell be-
comes ellipsoidal and there is a tendency for the two halves, each
containing one nucleus and one centrosome, to round up, which
is accomplished by a constriction furrow. This is particularly
true of some of the small eggs, as those of worms. On the other
hand, some eggs with large yolk, as those of the frog, retain their
general spherical form, and the furrow is more in the nature of a
line of dehiscence. Terni (71) has recently published figures which
show that amphibian cells may divide either by a broad curved

262 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN .

furrow (fig. 26), or a sharp furrow (fig. 25), or a broad furrow with
a sharp angle (fig. 40).

How widespread in the animal kingdom this very simple type
of cell-division may be is not entirely clear. Such cells as eggs
which occur free in the medium, lend themselves much more
readily to cell-division studies than do cells of tissues, such as
cartilage, muscle, etc. They are also of greater interest from a
reproductive standpoint, and hence it is no wonder that most of
our knowledge of animal cell-division is based upon the observa-
tion of such cells. In the minds of many zodlogists there has
not been an adequate distinction between the processes of nuclear
and cell-division. Rabl in 1885 published his paper entitled
“Ueber Zelltheilung’” (54), which devotes only two paragraphs
to cell-division proper, and over 100 pages to karyokinesis. This
simply serves to indicate the place of secondary interest to which
cytokinesis had been relegated.

None the less, a vast amount of effort has been expended in
attempting to find some equivalent in animal cells of Strasburger’s
beautiful and clean-cut figures of cell-division in the higher plants.
Hofmann (31) in 1898 published an excellent review of the litera-
ture bearing on the existence of a cell-plate in animals, and adds
some interesting observations on hydroids and Limax. He
deliberately chose animal cells which were imbedded in a matrix
having a high coefficient of viscosity and a low coefficient of
elasticity, so that the external conditions would closely simulate
those of most plants. There can be no doubt that he found
equatorial differentiations, as had Flemming and others before
him; but whether these should be considered homologous to the
cell-plate of the higher plants is not entirely certain. Unfortu-
nately, his preference for the iron-haematoxylin stain makes com-
parison with the leading botanical investigations difficult. No
orange zone is reported such as Timberlake found in the onion.
Only one figure of Limax and one of Trutta show an inflated spindle;
whereas many figures of all species studied present an hourglass-
shaped spindle. There are only a few cases noted of granules
fusing to form a plate, in most instances the granules remaining
quite distinguishable. Several cases show a large globular
zwischenkorper; and none show a centrifugal splitting of the
plate. The present tendency among reputable zodlogists is to

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 263

avoid the attempt to harmonize the cell-plate in plants with
any equatorial differentiation in animal cells; and it seems ad-
visable, at least, to use the term “‘zwischenkorper’”’ or ‘‘diasteme”’
for such structures in animals, reserving the word ‘“‘cell-plate”’
for the higher plants only.

e. Theories of cell-division

Very numerous theories of cell-division and related phenomena
have been offered. Perhaps most students have believed that it
is an expression of the working of the architectural mechanism of
the cell. One school believes that there is a radiating system of
organic rays about the centrosome. To this belong: Van Beneden,
Boveri, Flemming, Hertwig, Solger, Zimmermann, Heidenhain,
and Kostanecki. Von Fick (27) takes exception to this in that
it does not take account of the surface relations; and Rhumbler
assumes that cell-division is brought about by a combination of
surface forces and those of the internal mechanism.

A number of investigators have attempted to place the study on
a physico-chemical basis by proposing what have been referred to
as the dynamic theories of cell-division. Gallardo (22) reviews
the literature up to 1902. Fol in 1873 suggested that the achro-
matic figure resembles the arrangement of iron filings over a
magnet. Soon afterwards Strasburger referred to the resemblance
of the spindle to a magnetic field as a peculiar coincidence. A
number of workers modeled fields of force to represent mitotic
figures in various kinds of media; Giard in 1876 in liquids; Faraday
with sulphate of quinine crystals in spirits of turpentine; Gueblard
with copper and lead acetates; and Butschli with gelatin. Errera
in 1880 discredited the belief that there are electrical phenomena
at work in the cell by experiments with cells of Tvradescantia
dividing in the field of a powerful magnet. He interpreted cell-
division as a hydrodynamic process. Fick in 1897 made the sug-
gestion that macroscopic models cannot reproduce microscopic
phenomena, since capillarity and other molecular forces are at
work in the one but not in the other. Prenant contends that
there are two forces: a traction or centripetal force; and a com-
pression or a centrifugal force. Meves discredits the idea of the
fibers as representing lines of force on the ground that they often
cross; but Wilson affirmed that ‘‘the crossing of rays is not neces-

264 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

sarily fatal to the assumption of dynamic centers.’’ Gallardo
attempts to show how the tilting of the spindle may cause an
apparent crossing of fibers which really do not cross. The trained
cytologist will, however, hardly accept this as proof that there is
no crossing of fibers in the cell. Wilson objects to the dynamic
interpretation on the ground that it cannot explain the tripolar
figures. Hartog (29) has made, perhaps, the most careful
attempt to correlate the kinoplasmic fibers with lines of force.
He concludes that they are the result of a force which is “analogous
to magnetism, and still more to statical electricity.’’ Their
behavior is due to their relative conductivity: the fibers, mem-
branes, and chromosomes being of high conductivity.

Still more recently, interesting studies on the chemical changes
in the cell incident to cell-division have appeared. Robertson
(55) suggests that cholin is formed as a by-product about the
daughter nuclei, and diffuses in all directions, hence reaching its
maximum concentration in the equatorial plane. This causes a
diminution in surface tension along the equator and hence the two
hemispheres round up against each other. That the cleavage fur-
row is due to decreased surface tension is also held by Loeb and
Lillie; but McClendon and Biutschli contend that it is due to
increased surface tension at the equator, which brings about a
constriction in that region. McClendon (46) has performed
many unique experiments in support of his view; these have been
otherwise interpreted by Robertson, and the latter has devised ex-
periments to demonstrate the opposite contention; with the result
that there is still a question as to which condition does exist.

f. Terminology of cell-division

In spore-mother-cells each nuclear division may be at once
followed by cell-division, or cell-division may take place after the
four nuclei have been formed. There has been some confusion
in the terminology here. Strasburger referred to the latter process
at first by the term ‘‘simultan’’ (67a), and later (67f) by the
word ‘‘Viertheilung.’”’ The same writer refers to the process of
partition in Fucus and Sphacelaria as simultaneous, as opposed
to progressive. It seems that this term simultaneous shouid be
restricted to the type of cell-division in these brown algae, meaning
that the process of division is at the same stage of development

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 265

in all parts of the division plane. In referring to the two types
of division characteristic of spore-mother-cells, Guignard (26c)
calls them ‘‘bipartition successive’’ and ‘“quadripartition simul-
tanée.”’ I shall refer to them as simply bipartition and quadri-
partition respectively.

There is also some confusion as to the use of the word “tetrad.”
Farmer and many zodlogists have applied it to certain chromo-
somes in diakinesis, while it has also been used by others to refer
to the four spores resulting from a single mother cell. The latter
use, no doubt, grew out of the fact that these four spores are
frequently tetrahedrally arranged; and consequently there comes
the question as to whether four spores arranged in a monoplanal
rectangle or a rhomb should also be called a tetrad. In view of
this confusion and inasmuch as ‘“‘the four spores” is generally
understood as referring to the product of a single mother-cell,
+t seems more reasonable to restrict the term tetrad solely to the
chromosomes.

One more instance of confused terminology might be noted in
this connection. The terms, ‘“‘phragmoplast”’ and ‘‘cell-plate,”’
are used to refer to the same thing. The former is of more common
occurrence in the older literature, and its use has been resumed
recently by Ernst and Schmidt (15) and others. Inasmuch as
the structure in question is transitional, and during its existence
the cell is constantly undergoing transformation, it would seem to
possess little similarity to such permanent cell-organs as the.
plastids. Since the term, ‘‘phragmoplast,”’ suggests such a rela-
tionship, it should probably be abandoned, and the term “‘cell-
plate” alone be retained.

g. Quadripartition in cryptogams

As noted above, the phenomenon of quadripartition occurs in the
algae in the germination of the zygospore of Craterospermum [Mou-
geotia| and in the formation of the tetraspores of Chylocladia and
other red algae. Quadripartition has been reported in a number of
instances for the bryophytes. Strasburger was the first to do
this (67a), when in Pellia he reported a tetrahedral lobing of the
mother-cell, and division by cell-plates following. In the same
form Farmer has reported both bipartition (16c) and quadri-
partition (16d) by cell-plates with the nuclei tetrahedrally ar-

266 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

ranged. In Aneura [Riccardia] (17), Farmer and Moore describe
a transformation of the mother wall into a quadrilobed structure
during reduction. After the heterotypic karyokinesis a wall is
formed across the interzonal fibers; after the homoeotypic division
the respective lobes are delimited from each other at the center
of the original cell, by walls which take up the same position as
do soap bubble films when placed in boxes of corresponding form.
Ultimately fresh walls are formed around the content of each cell,
and the spores separate by the solution of the original walls.
Earlier (16a) Farmer had described quadripartition into four
tetrahedrally arranged spores in Pallavicinia and Aneura as
taking place only partially by cell-plates, ‘‘the cell-walls at their
inner angles grow into the cell-cavity,’’ and the spores finally
become separated by the appearance of membranes. In Fossom-
bronia and Plagiochasma, he is uncertain as to the relation of cell-
plates to cell-division. He has also reported (16d) quadripartition
by cell-plates in Fegatella [Conocephalum], in which they are in the
form of a rhomb, with five connecting spindles instead of six. In
all his work Farmer has omitted reference to the mother-cell-wall
and fails to show it in most of his drawings.

The conditions which obtain in Anthoceros have been more
extensively studied and by more investigators. Von Mohl (430)
first described the division by ‘‘auf der innern Seite der Zell-
wandung hervorsprossende Leisten . . . spater gegen die Mitte der
-Zelle zusammenwachsen und sich daselbst vereinigen’’ (pp. 282,
283). Schlacht (62) later (fig. 46) indicated centripetal develop-
ment of a cell-wall after the cleavage of the content (fig. 41).
Hofmeister (32b) found the same procedure and studied it by
plasmolyzing the cell-content and observing the projection of
the new walls centripetally. He adds the interesting observation
that the mother-wall swells during the process of division.
Strasburger (67a) in the publication in which he established
the predominance of cell-plates in the cell-division of higher
plants by multiplying the cases of its occurrence, reports that
Anthoceros has in its spore formation a tetrahedral quadriparti-
tion by cell-plates, followed by a rounding up process. The
most recent work upon this genus is that of Davis (11). He
agrees that the quadripartition is tetrahedral, but notes that the
fibers crossing the division-planes are not parallel, but assume

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 267

varying courses and may anastomose. These he believes are
not the spindle fibers but rather that they have arisen after the
spindle, resulting from the homoeotypic karyokinesis, has dis-
appeared. In this case the cell-walls are formed in the cyto-
plasm without reference to the fibers. His figure 26 indicates
the development of a cell-plate from the center of the tetranucleate
mother-cell outward in three (in all, six) directions toward the
mother-wall. This should be described then as neither a centri-
petal nor a centrifugal development, for the latter terms should
be used with respect to the individual spindles, and not to the
cell as a whole; it might better be referred to as progressive from
one side of the spindle to the other, such as Treub noted in his
study of the orchids. In view of the following study it is evident
that further investigation of cell-division in the mother-cells of
Anthoceros should be undertaken.

The mosses have scarcely been studied at all in this respect.
Sachs on page 13 of his textbook (59) reports tetrahedral quadri-
partition in the spore-formation of Funaria. Hofmeister (326)
shows that the mother-wall of Phascum swells to eight times its
original thickness, and the cell doubles its diameter during the
reduction divisions.

In the ferns several cases of quadripartition have been reported.
Calkins (9) describes such in Pteris, where division occurs tetra-
hedrally and by cell-plates, but no figures are given of the process.
In Osmunda a similar instance is given by Smith (G5). » Elere:the
tetrahedral arrangement of the nuclei is said to be brought about
by a rotation of the spindles and chromosome aggregates during
the homoeotypic karyokinesis, the heterotypic spindle having
meanwhile broken down into a granular mass. In Botrychiwm
Stevens (66) describes a similar dense equatorial plate of cyto-
plasm following the heterotypic spindle. In this species the
nuclei at the time of quadripartition may be arranged either in a
tetrad ora rhomb. The division is by cell-plates and the mother
cell-wall is not shown to thicken during the process. In Polypo-
dium, Russow (58) described successive bipartition, the mother-
cell-wall swelling in water.

Among the fern allies there is a considerable range of variation
in the cytokinesis incident to spore formation. For Equisetum
Russow (58) reported tetrahedral quadripartition, the division of

268 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the protoplasm beginning at the center of the mother-cell and
proceeding outward. Hofmeister (32), however, noted that
there was successive bipartition and that a plate of granules, or
sometimes a ring of granules at the equator preceded the centrip-
etal development of the partition wall. Strasburger (67a),
describing the same species, says that there are irregular masses
of material heaped up in the equatorial plane. He describes the
division as quadripartition by cell-plates, the position of the nuclei
being either tetrahedral or monoplanal. The mother-cell-wall is
reported to swell when placed in a glycerine solution. His figures
(67b) are not entirely convincing that there is a plate and not a
row of granules across the equator, and they do not demonstrate
a centrifugal partition. In Psilotum he (67a) also shows an equa-
torial accumulation of material at the time of the two successive
divisions. In the same form Hofmeister (325) reports monoplanal
quadripartition and mentions a girdle of granules about the equator
““ohne dass das Auftreten einer solchen Scheidewand vorausginge.”’
In Jsoetes Strasburger (67a) reports tetrahedral quadripartition
by cell-plates, the fibers crossing and swelling at the equator.
In Marsilea Russow (58) reported tetrahedral quadripartition;
and more recently Strasburger (677) has published quite an ex-
tensive paper on Marsilea in which he reports quadripartition in
both the macrospore and microspore formation. His figures show
both a monoplanal and a tetrahedral arrangement of the nuclei
in the metaphases of the homoeotypic division. The microspore-
mother-wall is shown in the figures to be thickened, but no thick-
enings of the fibers are shown. Strasburger (67d) has also re-
ported quadripartition in Lycopodium.

h. Quadripartition in gymnosperms

In the cycads also the mother-wall thickens during the reduction
divisions. In this group, however, division into spores is accom-
plished by two successive bipartitions. The nuclei may lie either
in one plane or in a tetrad, as described by Juranyi (36) for Cerato-
zamia. His figures of the first division show constriction fur-
rows accompanied by thickening of the mother-wall. Stages in
the second division are not figured. Treub found rather obscure
cell-plates in the first division of Zamia (75d).

In the larch, as noted above, Timberlake has reported both

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 269

quadripartition and bipartition (73), with a predominance of the
latter. Harper (28d) asserts that in the former cases the materials
of the spindles of the heterotypic division may be used in the
homoeotypic nuclear divisions. Hofmeister (32) reported centrip-
etal division of the cytoplasm in the spore formation of certain
_ Abietineae, but this has never been confirmed. He also notes
the absence of a cell-plate and the swelling of the mother-cell-wall
in the divisions in Pinus.

1. Pollen-formation in monocotyledons

In the monocotyledons a considerable number of instances of
quadripartition have been reported. Mottier (44c) shows it
in his figure of the embryo-sac of Helleborus, where the nuclei
are arranged in a rhomb, with five spindles and upon each a cell-
plate. The same investigator gives an interesting figure from the
embryo-sac of Lilium. The four nuclei at the micropylar end of
the sac may be arranged either in one plane or tetrahedrally, the
latter condition being shown in the drawing. Cell-plates are
formed between each pair of nuclei, and also one on the fibers
which extend from the egg into the cytoplasm of the embryo-sac.
This is one of the few instances of cell-plate formation on fibers
which do not run between nuclei. Others are the embryo-sac of
Ephedra studied by Strasburger, and the embryo development of
Picea as shown by Hutchinson (33) in his figure 41.

The strong tendency to believe that all cell-division in the higher
plants proceeds according to the classic type of Strasburger’s
central spindle and cell-plate formation has been noted. None-
the-less the literature contains some indications that in many
cases of quadripartition the process may be a furrowing from the
surface inward, quite as in the animal and many lower plant cells.
Berthold (6) in 1886 wrote (p.217): ‘‘ Beidersimultanen Viertheilung
der Pollenmutterzellen scheinen bemerkenswerthe Besonderheiten
nicht aufzutreten. Die neue Zellplatten bilden sich hier entweder
wie gewohnlich bei den hoheren Pflanzen und auch in den Spore-
mutterzellen von Anthoceros und Isoetes zuerst frei im Zellraum,
um erst nachtraglich an die alte Membran sich anzusetzen, oder
aber sie dringen von dieser aus, Cladophora und Spirogyra ent-
sprechend, gegen das Zellinnere vor, wie oben schon erwahnt, in
Form dicker, plumper Leisten.”’

270 *MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Of cell-division in the pollen-mother-cells of the higher plants
von Mohl (43c) as early as 1851 made the following remark: “ Eine
eigenthimliche Bildungsweise, welche die Theilung der Zellen
und die freie Zellbildung verbindet, zeigen die Pollenkorner und
die Sporen der hoheren Kryptogamen. Die Mutterzelle der-
selben theilt sich nach vorausgegangener Entwickelung von vier,
aus der Theilung eines einzigen Kernes hervorgehenden Zellen-
kernen und gleichzeitiger Resorption desjenigen Kernes, welcher
zu ihrer Entstehung Veranlassung gegeben hat, durch Einfaltung
ihres Primordialschlauches und allmahlige Ausbildung von Scheide-
wanden (derenes je nach der relativen Lage der Zellenkerne vier oder
sechs sind) in vier Abtheilungen (Naegeli’s Specialmutterzellen)
oder sie theilt sich zuerst in zwei Abtheilungen, welche sich wieder
in je zwei Kammern (Naegeli’s Specialmutterzellen zweiten
Grades) abtheilen. Hofmeister (32a) in 1861 attempted to
distinguish between the monocotyledons and dicotyledons on the
ground that the cell-plate in the former is progressively formed
from one side of the cell to the other, whereas in the latter, ac-
cording to von Mohl’s observations on the Malvaceae, it develops |
centripetally. At the same time he reported that quadripartition
occurred in Naias major and in two species of Iris. Later (320)
he placed pollen-mother-cells of Jris in water and found that in
one-half hour the mother-wall becomes thickened and the proto-
plast divides by constriction furrows. Dippel in 1869 distin-
guished between the monocotyledons and dicotyledons on the
basis of bipartition and quadripartition in the pollen-mother-cells
respectively; and Samuelson (60) and others have more recently
reiterated this view, noting such exceptions as Nymphaea and
Asclepias.

Guignard has been most active in accumulating evidence that
quadripartition occurs in monocotyledons. He first found it in
orchids (26a) where cell-plates are formed from a series of granules,
and stain a pale violet with haematoxylin. He shows only one
figure of the process, and in this the four nuclei lie in one plane
and granules but no plates are present in the equators. On the
other hand, Hofmeister’s (32a) figures of bipartition in WNeottia
ovata and Orchis Morio indicate incipient constriction, but are
unaccompanied by description. Guignard (26c) very recently
has published a note giving a list of monocotyledons in which he

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 271

has observed quadripartition. This includes three species of
Aloe, four of Iris, two of Sisyrinchium, three of Ixia, two of
Antholyza, and one each of Freesia, Haworthia, Monbretia, Gasteria,
and Apicra. He also refers to the literature on the occurrence of
quadripartition in monocotyledons and bipartition in the pollen-
mother-cells of dicotyledons. He cites as cases of the former the
work of Strasburger on two species of Asphodelus, and of Tangl,
Strasburger, and Juel on Hemerocallis, besides referring to his
own study of orchids, in all of which, except Cypripedium, he found
quadripartition. As presenting cases of bipartition in _pollen-
formation of dicotyledons he mentions the following papers:
Strasburger on Ceratophyllum; Ernst and Schmidt on Rafflesia;
Strasburger, Frye, and Gager on Asclepias; and Frye and Blodgett
on Apocynum. Asshowing intermediate types of partition he refers
to the work of Samuelsson on Anona and Aristolochia, to his own
observations on Magnolia, and to those of Andrews on Magnolia
and Liriodendron. Guignard has not yet published his study of
the cytology of the process, but notes the tetrahedral arrangement
in Sisyrinchium, and the thickening on the inner surface of the
mother-wall at the point of insertion of the partition. The paper
very clearly establishes the situation as to quadripartition in the
flowering plants.

Hofmeister (32) in 1867 showed that division in the pollen-
mother-cells of Tradescantia occurs by cell-plate formation. And
Baranetsky (4) has since confirmed this. Miyake (42) shows a
figure (152) of what should probably be interpreted as a cell-
plate in this form; and the nuclei lie far apart at the time of
its formation. In Allium also he figures a cell-plate after
the heterotypic karyokinesis with the nuclei far apart. He also
reports a cell-plate following the same division in Galtonia.
Strasburger (67a) had previously shown that two successive bi-
partitions by cell-plates occur in Fritillaria, Lilium, Allium, and
Anthericum. His figure of the last-named form shows very well
the centrifugal splitting of the cell-plate and the centrifugal
formation of the new wall between the new plasma membranes.
In Allium he claims, as Wimmel (82) had previously figured,
that the mother-wall enlarges and that the cell-plate after the
heterotypic karyokinesis may be accompanied by a constriction,
“ein ringformiges Beginnen dieser Zellwand an der Wand der

272 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Mutterzelle.”” Tschistiakoff (76) says of Epilobium that the
division is by constriction of the plasma membrane, the cell-wall
being formed from the periphery inward and from the center out-
ward; that is, a combination of centripetal and centrifugal wall-
formation (p. 82).

No careful and complete study of the sequence of stages has been
given for any one of these plants. In most instances the evidence
consists of an isolated drawing without a description, or a state-
ment with neither description nor drawing to substantiate it.
Lilium has perhaps been studied more than any other form. In
addition to Strasburger’s early work, Farmer (160) in 1895 affirmed
that a cell-plate was present after the heterotypic karyokinesis,
as did Mottier (44a) a year later. Allen (1a) in 1905 published a
figure of a cell-plate in the heterotypic division and says that the
same occurs in the homoeotypic mitosis. The nuclei are shown to
be far apart during cell-plate formation. Schaffner (61a) a year later
also published asingledrawing of acell-plate in the heterotypic divis-
ion. In his textbook Sachs (59) shows successive bipartition in
Funkia, ‘‘a lamella of the cell-wall completely divides the mother-
cell. . . . The place where the wall of the mother-cell and the partt-
tion-wall meet soon becomes thicker, and the two daughter-cells here
become rounded off.’’ Wiegand (80) shows a figure of a cell-
plate after the heterotypic karyokinesis of Potamogeton, the peri-
pheral portion of which is without spindle fibers. Of Convallaria
he says, ‘‘A strong nuclear plate follows the division resulting in a
cross wall separating the cell into two hemispherical parts.”’
There may be some question as to whether this is the correct use
of the term, nuclear plate. Duggar (140) gives one figure of a cell-
plate in the heterotypic division of Symplocarpus, and a similar
one of Peltandra. For Trillium Atkinson (3) gives two figures of
cell-plates in the heterotypic division. In like manner Schaffner
(61d) treats Agave. For Galtonia Miss Digby (13a) shows a
thickened mother-wall and a cell-plate in her figure 72.’ In
figure 81 she shows the homoeotypic division occurring apparently
after cytokinesis had taken place in the first division; but in
figure 79 there is no indication that cell division had occurred
previous to the second division. No discussion of this appears
in her paper. Tangl (70) in 1882 reported quadripartition with
four cell-plates accompanied by an invagination of the mother-

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 273

wall in Hemerocallis, but the same year Strasburger (67c) pub-
lished the statement that the cell-wall is constructed after the
first division in this form. Juel (35a) in 1897 presented a long
paper in which he showed that the cell-plates after the heterotypic
karyokinesis in Hemerocallis are incompletely developed and
remain suspended in the cytoplasm. The same writer later (35d)
reported ephemeral cell-plates in Carex after both the heterotypic
and_homoeotypic karyokineses. _ In Zea Mays s Kuwada (37) has
reported that after the heterotypic karyokinesis the mother-cell
occasionally constricts without the formation of a cell-plate
(text-fig. 2); this he associates with a subsequent amitosis and the
frequent abortion of the pollen. He found the peculiar constric-
tion in only two preparations. In Musa Tischler (74d) describes
(p. 637) the daughter cells afterthe heterotypic nuclear division as
“durch Plasmamembranen voneinander abgegrenzt.’’ The
daughter-cells re-divide several times in various planes, forming
either a row, a sphere, a square, a rhomb, etc.

j. Pollen-formation in dicotyledons

The evidence regarding the formation of cell-plates in the pollen-
mother-cells of dicotyledons is even more variable and fragmentary,
though the authors’ statements are frequently very positive.
Naegeli (47) in 1842 was the first to publish on this point. For
Oenothera he shows a figure of tetrahedral quadripartition, in
which the mother-cell-wall is thickened. He figures a similar
condition for Cucurbita Pepo and Bryonia, in the latter case
showing an evident constriction. He describes the process only
briefly, ‘‘auf der innern Oberflache der Membran sechs_ vor-
springende Leisten; dann pl6étzlich die Bildung von Scheidewanden,
die sich in Centrum berthren.’’ He believes, however, that the
dividing layers are of the nature of cell-plates and not ingrowths
of the cell-wall, as he attempted to show by plasmolysis.

In 1850 Wimmel (82) confirmed the observation of Naegeli on
Oenothera and added studies on two or three other genera. In
Convolvulus he found that the division is accomplished by a fur-
rowing and shows a figure of the process. The mother-wall is
considerably thickened. In Momordica Elaterium he found a
successive division, and figures the mother-wall here also as some-
what thickened. In Althaea rosea he figures a division by cell-

274 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN~™

plate with the mother-wall somewhat thickened. Three years
later von Mohl (43c) published figures of spore formation in the
same plant which indicate a division by constriction sometimes
accompanied by a cell-plate and sometimes not.

In 1854 Pringsheim (53) prompted by the work of von Mohl,
to whom he refers in his preface, presented a study of bipartition
and quadripartition in pollen-formation. On page 54 he describes
the thickening of the mother-cell-wall by regular layers as in
collenchyma formation. In Althaea there is a quadripartition,
either monoplanal or tetrahedral, which appears first as ‘‘Tren-
nungslinien.’’ Division, he says, is, however, accomplished by
the ingrowth of the mother-wall, as in the Conferveae. In figure 4,
plate IV, there is represented a monoplanal square, with aridge on
the inner surface of each of the four sides of the mother-wall,
and a square area in the center. He does not adequately describe
this central square. From the following study it will be seen
that it is not unlikely that the central square represents a mass of
mother-wall material which has followed the constriction furrows
toward the center of the tetranucleate cell. In 1865 Rosanoff (56)
published a couple of figures, 24 and 25, of Acacia paradoxa in
which are shown successive bipartition, the second division of
which is accomplished by constriction, and invagination of the
mother-wall at right angles to the first division and beginning
first along the periphery on the mother-wall and only after a time
becoming apparent on the division wall of the heterotypic mitosis.
The author does not discuss the process.

Hofmeister (320) in 1867 included in his book on the “ Pflanzen-
zelle’’ certain studies of pollen-formation which have not been
followed up by later investigators and seem to have been quite
forgotten in the recent tendency to ascribe all division of plant
cells to the activity of a cell-plate. However, in the light of the
following study and of much evidence which has up to the present
remained quite isolated, it seems just to attribute to Hofmeister
priority in grasping the real situation as to the pollen formation
of dicotyledons. Not only did Hofmeister study Althaea rosea,
which had received so much attention previously, but he also
worked on the Cucurbitaceae and the Passifloreae, in addition to
certain monocotyledons and Anthoceros. In the dicotyledons he
reported a centripetal quadripartition and figured it in Passi-

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS PAG:

flora. In addition to observing the living material, means were
used for studying the wall and protoplast separately. He
dissolved the wall by means of sulphuric acid or copper-oxy-
ammonia, whereupon he could see the constriction furrows in the
plasma membrane independent of the cell-wall. On the other
hand he plasmolyzed the cell-content and in this way assured him-
self that the ridges upon the inner surface of the cell-wall grow
centripetally to cut the protoplast into the daughter-cells. As
noted above, in Jris he induced division by causing the mother-
wall to swell in water, but he does not report the repetition of
this for any dicotyledons, though he did induce the cell-walls to
swell. On page 71 he states that the gelatinization of the cell-
wall permits the enlargement of the protoplast. If, however, the
inner layers only swell, the cell-content is compressed. In addi-
tion to quadripartition he also reports bipartition by cell-plate in
Passiflora.

Seven years later Sachs (59) presented a whole series of figures
of quadripartition in the pollen-formation of Tropaeolum minus.
These are evidently drawn from living material and show various
conditions of shrinkage and collapse of the protoplast, which, as
will be shown later, do occur in material crushed out under the
cover-glass. The drawings show very well the thickened wall,
and the centripetal formation of the cross-walls. In his discussion
Sachs does not agree exactly with the interpretation of Hofmeister
and conceives of quadripartition being brought about by absorp-
tion of the heterotypic cell-plate and the reconstruction of it in
addition to the formation of other cell-plates after the homoeotypic
karyokinesis. He says that quadripartition in Tropaeolum occurs
by the ingrowth of the mother-cell-wall at its junction with the
cell-plates. He, however, does not support this contention by
drawings.

Strasburger followed the next year with his famous work on the
formation of cell-plates (67a + 6) in a great many plants, in
which he included drawings of what he interpreted as cell-plates
in the pollen-formation of Tropaeolum majus. This is the most
complete series of stages in division of the pollen-mother-cells of
any dicotyledon that Strasburger has ever published, his other
studies presenting merely single drawings. A careful survey of
these drawings of Tvopaeolum reveal apparently swellings of the

276 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

spindle fibers at the equator, but the evidence that these form a
plate is by no means convincing. When it is remembered that
this material was fixed in alcohol, and that Strasburger repeatedly
expressed his opinion that the pollen-mother-cells of dicotyledons
were very unfavorable material for study, there arises a grave
doubt as to whether we are justified in accepting these drawings
as final proof of the existence of true cell-plate formation in this
species. In his discussion he recognizes an ‘‘Einschnurung”’ of
the mother-cell, and a thickening of the wall at the equator in the
form of a ridge.

On division in the pollen-formation of other dicotyledons,
Strasburger gives a few fragmentary remarks. He noted quadri-
partition in Cucumis, Delphinium, Aconitum, Glaucium, Althaea,
and Bryonia, but gives no figures or descriptions of the process.
In his paper on Asclepias (67h) in 1901, Strasburger showed a
peculiar condition, where successive bipartition of the pollen-
mother-cells results in a row of four cells. The mother-wall is
not thickened, in fact it is scarcely discernible in the drawing.
His only descriptions of the division processes are that they are
by cell-plates. The following year he published (672) his Cerato-
phyllum paper, in which he includes no description of cell-division
but only one figure, number 46. The mother-cells appear to be
closely packed, and to have very thin walls. A partition appar-
ently results from the heterotypic mitosis. The second division
may be either monoplanal or tetrahedral.

A few papers have given rather good evidence of the existence
of cell-plates in the mother-cells of dicotyledons. Ernst and
Schmidt (15) recently found successive bipartition by means of
cell-plates in Rafflesia. It is stated that the nuclei may be arranged
either monoplanally or tetrahedrally. Frye and Blodgett (21)
in 1905 also reported successive bipartition in the pollen-mother-
cells of Apocynum. They do not discuss the details of the process,
but show that it may result in the four spores being arranged
tetrahedrally or monoplanally in a square, rhomb, pyramid, or
row. In the drawing of the monoplanal square they suggest the
existence of a cell-plate, following the homoeotypic karyokinesis.
The mother-wall is not shown to be thickened.

In 1907 Lubimenko and Maige (40) described a peculiar division
in Nymphaea in which a cell-plate is formed after the heterotypic

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS akg |

karyokinesis, but disappears before cell-division is accomplished.
Their figures indicate a tetrahedral quadripartition; but in only one
figure, 54, is acell-plate indicated, and this after the second nuclear
division. The mother-wall in the drawing is about one twenty-
second of the diameter of the cell. During exine formation the
mother-cell-wall is shown to be much thicker. They explain (p.
450) their omission to figure a series of stages in the cell-plate
formation after the homoeotypic division as due to a condensation
of the cytoplasm about the nucleus, and the formation of a cell-
plate so quickly that the different stages could not be found.

The pollen-formation of Magnolia has been investigated by sev-
eral; and apparently it is of another intermediate type. Guignard
(26d) found that the heterotypic spindle enlarges by the forma-
tion of new fibers. Before it reaches the plasma membrane the
fibers become very conspicuous and stain heavily in the equatorial
region. A granular plate is not shown to appear in the center, but
the fibers are grouped together, leaving clear spaces between them.
Soon a ridge appears on the inner surface of the mother-cell-wall,
which in optical section resembles a wedge projecting toward the
center of the cell. This furrow he likens to those in the cell-
division of Cladophora and Spirogyra. The invaginating ring is
heavier than in the latter, and the fibers do not thicken enough to
account for its ingrowth. As the ring advances the spindle fibers
on either side disappear. It does not regularly at this time con-
tinue its growth until cytoplasmic division is complete, but stops
when the depth of the furrow is about equal to the breadth of
the isthmus or protoplasmic bridge remaining between the two
halves of the mother-cell. In a few cases the division is
said to be complete. The fibers are reformed across the isthmus
after the homoeotypic division, and the cytokinesis previously
begun is completed usually slightly before the daughter-cells
divide. The second division is said to begin like the first, but is
more rapid and continues without interruption. He shows no
figures of these later stages, which, in fact, constitute the crucial
point in establishing the nature of this division. This work was
succeeded in 1901 by that of Andrews (2). In the title of his
paper he includes both Magnolia and Liriodendron, and he does
not indicate in his drawings from which plants they were taken.
He agrees in most particulars with Guignard, except that he

278 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

states that the first division is completed by the formation of a
cell-plate across the isthmus. ‘‘The formation of the cell-plate of
the second mitosis is about in the same way”’ (p. 139). His figures
show constrictions of the protoplast, but in no case do they indicate
the semblance of a cell-plate. The most recent work on Magnolia
is that of Maneval (41). He makes no reference to the work of
Guignard, but says that the division is simultaneous, while his
figures are not entirely in harmony with this interpretation.

In 1914 also there appeared the paper of Samuelsson on
Anona and Aristolochia (60) in which he attempts to establish a
relationship between rhonocotyledons and dicotyledons on the
basis of the occurrence of both bipartition and quadripartition of
the pollen-mother-cells in these forms. In Aristolochia he reports
successive bipartition, resulting in a monoplanal square or a pyra-
midal arrangement of the spores. In Anona he figures a mono-
planal square in which the mother-cell-wall is in thickness about
one fourteenth of the diameter of the cell. As Guignard found in
Magnolia, he reports for Anona that in the telophases of the
heterotypic mitosis the division of the cytoplasm begins as an
equatorial constriction on the periphery of the cell, which is
completed after the homoeotypic karyokinesis. The cytokinesis
after the homoeotypic karyokinesis is said to agree completely
with the first. He does not refer to a cell-plate in any connection
throughout the whole paper. He gives no description of his
drawings, which appear to be very poorly reproduced. Shibata
and Miyake (63) present a similar case in Houttwynia, which they
consider as associated with the abortion of pollen in that form.

It thus appears that there are a number of dicotyledons which
display a type of cell division of the pollen-mother-cells which has
been regarded as intermediate between true bipartition and true
quadripartition. It is generally recognized, however, that the ma-
jority of dicotyledons form their microspores by a quadripartition
of the mother-cells; but the details of this process of quadriparti-
tion have not been accurately determined, and the data in the
literature regarding it is not entirely consistent. Some papers as
noted below give evidence of the existence of cell-plates in this
cytokinesis, while others indicate that it may be accomplished by
furrowing.

In 1898 Lawson (38) published in the Proceedings of the Cali-

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 279

fornia Academy of Sciences a figure, 24, of Cobaea which shows a
pollen-mother-cell after the homoeotypic karyokinesis with the four
nuclei tetrahedrally disposed and not appressed to the plasma
membrane, though cytoplasmic division has not yet occurred.
The spindles are inflated and the mother-wall is about one thirtieth
of the diameter of the cell. There is a concavity of the plasma
membrane on one side of the mother-cell, a convexity on another,
and the third side is flattened. ‘‘ Cell-plates are now formed in the
usual way’’ (p.178). Two years later there (8) appeared in the same
journal a paper by Miss Byxbee on Lavatera. Her figure 24, also
of a mother-cell, has four nuclei arranged in a monoplanal rhomb also
with the suggestion of five spindles between them. The mother-
cell-wall is here about one twenty-second of the diameter of the
cell, and there is no indication of the division of the cytoplasm
either by cell-plates or by furrows. Here also the statement is
made that ‘‘cell-plates are formed later on’’ (p. 69). This is the
only reference to cytokinesis in the paper. It is evident that the
statements as to cell-plates in both Cobaea and Lavatera must be
regarded as quite unreliable.

Tischler has reported a number of instances of quadripartition
in pollen-formation, but has never described the details of the
process. In 1906 in connection with his study of sterile Bryonia
hybrids (74a), he gives a figure, number 7, of a mother-cell in
which quadripartition would no doubt occur. But he does not
refer to it in the text, nor does the drawing show the mother-cell-
wall. In the same year in his study of Rzbes hybrids (740), he
presents two figures indicating quadripartition, one tetrahedral,
the other rhomboidal. In 1908 in further work along this line,
he gives a number of similar figures (74c). Number 14 shows
the mother-wall thickened to about one fourteenth of the diameter
of the cell in Mirabilis. Number 19 indicates that bipartition
has occurred after the heterotypic division, the mother-wall
being about one twentieth of the diameter of the cell. In figure 71
he shows a tetranucleate cell of Potentilla, with the mother-wall
thickened to one tenth the diameter of the cell. Figures 99 and
100 show a like condition in Syringa. Of Mirabilis he writes (p.
44), ‘In nicht wenigen Fallen gelingt aber die Ausbildung der Zell-
platte nicht mehr: wir erhalten vierkernige Zellen.’’ This con-
stitutes the only evidence which he gives of having seen cell-plates

280 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

in any of these forms. Of Syringa, Juel (355) states that there
is quadripartition by cell-plates, but gives no figures to show it.
In the same way Duggar (14a) refers to Bignonia, but his figures
do not show cell-plates.

In his paper on reduction in the pollen-mother-cells of dicoty-
ledons, Overton (51) presents a figure of Podophyllum, number 70,
which indicates cell-plate formation after the heterotypic division.
The mother-wall is not shown, and the division is not discussed
in the paper. Mottier (44a) in his paper on the same subject,
based also on Podophyllum, shows that cell-division does not always
occur after the heterotypic division. He gives two figures after
the homoeotypic karyokinesis with the four nuclei arranged in a
rhomb, with five spindles connecting them. No cell-plates are
shown. By four figures of late stages of the heterotypic division
he shows that the spindle fibers of that division disappear in the
center and are replaced by a granular plate. In his text he says
only, “‘ Die Zellplatte wird in der fir Lilium zuvor beschriebenen
Weise angelegt.”” We must conclude that in Podophyllum an
ephemeral cell-plate is formed after the heterotypic division,
but the division after the homoeotypic karyokinesis should be
further studied.

Wille (81) in 1886 presented a paper on the formation of the
wall of the pollen grains of 22 different plants, in which are inci-
dentally introduced a number of observations of interest in the
present study. He devotes especial attention to the thickening
of the mother-wall, which he contends is by intussusception, but
gives no evidence that anything more than a swelling or gelatiniza-
tion actually occurs. The thickened wall is said to be made
up of “‘wasserarme und wasserreiche Schichten,’’ as Naegeli
and Strasburger held for starch grains. Though both mono-
cotyledons and dicotyledons were studied, he considers divi-
sion of the pollen-mother-cell as taking place in all cases by suc-
cessive bipartition by cell-plates. At the end of this paper Wille
reports a number of instances of the formation of pollen grains
in other than groups of four, the irregularities ranging from one
to fourteen in different species. He also described lobed micro-
spores as occurring along with the normal globular forms.

It appears that in no instance is the evidence conclusive that
quadripartition of the pollen-mother-cells of any dicotyledon “is

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 281

effected by means of cell-plates. That some dicotyledons form
their microspores by two successive divisions with cell-plate forma-
tion, can scarcely be doubted, as is shown in Asclepias, Cerato-
phyllum, Apocynum, and Rafflesia. But it is generally recognized
that the majority of pollen-mother-cells of dicotyledons do not
divide in this way. The best evidence of quadripartition by cell-
plate is that of Strasburger in his work on the alcoholic material
of Tropaeolum, which has been shown above to be not beyond
question. On the other hand there is some evidence that cleavage
furrows may be involved in the process. The work of Naegeli,
Wimmel, von Mohl, Sachs, and Hofmeister suggest it, though
such early work should not be taken as by any means final. Guig-
nard and Samuelsson directly affirm it in Magnolia and Anona
respectively.

There is also a considerable list of additional papers which in
one way or another indicate that furrowing may be involved in
the division of the pollen-mother-cells. As early as 1880 Bar-
anetsky (4) in addition to confirming Strasburger’s observations
on successive bipartition by cell-plates in the pollen-mother-cells
of Tradescantia, studied this stage in four different dicotyledons.
He shows two figures of Hesperis matronalis with incipient furrows
along the equator. He does not describe them, but says, ‘‘Stras-
burger gibt an, dass ‘in allen Fallen’ der Theilung der secundaren
Kerne die Bildung einer Zellplatte zwischen ihnen vorausgeht.
Bei den von mir tberhaupt beobachteten Dicotylen: Pisum sativum,
Lathyrus odoratus, Hesperis matronalis, Ipomaea tricolor, konnte
ich diese Angabe nicht bestatigt finden.”’

Ishikawa (34) in his figure, number 11, of Dahlia shows a pollen-
mother-cell in which four nuclei are tetrahedrally arranged. They
do not lie near the plasma membrane, but spindles are shown ex-
tending between them without the slightest indication of a cell-
plate. At the equator on one side there is a concavity, and the
other two sides are flattened. No mother-wall is shown, and the
paper contains no discussion of the process.

Osawa (500) shows several figures of division of the cytoplasm
in the pollen-mother-cells of Taraxacum. Figure 22 is of a pollen-
mother-cell with four nuclei tetrahedrally arranged; no mother-
wall is shown. The spindle fibers are thickened at the middle
throughout about one half their length. One side of the cell is

282 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

concave, and two flattened; no cell-plate is shown. In the text he
only says ‘‘ the cell-walls are formed between these four nuclei, pro-
ducing the normal tetrad.’”’ Figure 55 shows an instance of biparti-
tion of the pollen-mother-cell. In Daphne he (50a) shows a marked
furrow on two sides of the mother-cell, which is about to undergo
tetrahedral quadripartition. There are also indications of cell-
plates here. The mother-wall is about one ninth of the diameter
of the cell. ;

Rosenberg (57a) shows a schematic drawing, text figure III.,
of successive bipartition in Hieracitum venosum. In text figure V.
he hasa tetranucleate mother-cell which is rectangular, and without
a thickened wall. Hesays (p. 149), ‘‘ The following division stages
correspond with, for instance, those of Tanacetum or Taraxacum,
and the development of the pollen cells does not offer anything
extraordinary.’’ In no instance does he show a cell-plate. Of
Drosera he shows several figures of quadripartition. Figure 22
(57b) shows the four nuclei in one plane in the form of a rhomb,
with four spindles of equal size, and a fifth small spindle between
the two opposite nuclei which are in closest proximity. No
indication of a cell-plate is shown. Figure 21 shows a similar
stage with tetrahedral arrangement of the nuclei. In figure 2 the
mother-wall is shown much thickened and a cleavage furrow is
beginning in the equator at the metaphase of the homeotypic
division. Nocell-plates are likewise shown here. During thecourse
of my investigation on Nicotiana and other forms described below,
Levine (39) in his studies on the germ cells of Drosera observed
both bipartition and quadripartition in which the mother-cell-wall
is much thinner and more angular, as in Asclepias, Ceratophyllum,
etc. His figures show no broad constriction furrow, and at the
stage when partition has apparently just been completed, the
appearance is as if the mother-cell had divided by cell-plate forma-
tion. Drosera is one of the plants in which the four pollen grains
thus formed. never separate. Whether this has anything to do
with the mode of cytokinesis in microspore formation is a problem
for further investigation.

In her study of Parnassia Miss Pace (52) presents a figure, 54,
which shows tetrahedral quadripartition with the invagination of
the thickened mother-wall along the equators. Fibers are shown
crossing the equator, but there is no indication of a cell-plate.

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 283

The paper contains no discussion of this peculiar situation. Shoe-
maker (64) in Hamamelis shows tetrahedral quadripartition with
an incipient furrow in figure 31. The mother-wall is much thick-
ened, and no cell-plate is indicated. Miss Fraser (20) in her
figure 31 of Vzcza indicates tetrahedral quadripartition; spindles
are shown, but no cell-plates; the plasma membranes are rather
indistinct, but there are indications of equatorial cleavage furrows.
Miss Digby (130) in her figure, 42, of Primula indicates tetrahedral
quadripartition with broad furrows on both sides, which are,
however, not exactly equatorial. No cell-plates are shown. In
figure 67 the mother-wall is shown to be greatly thickened after
the division is complete. She writes, ‘‘The cytoplasm between
the nuclei constricts,’’ but she makes no reference to the presence
or absence of a cell-plate. Miss Nichols (49) reports tetrahedral
quadripartition, in which the cytoplasm ‘“constricts.’’ Her
figure 39 shows such a condition, but there are only two, nuclei
shown. Gregory (25) figures for Lathyrus a constriction of the
protoplast after the heterotypic division. This he states is
accompanied by amitosis and is related to sterility of pollen. He
evidently regards it as abnormal, as he says that in the fertile
pollen the division is ‘“‘of the usual type.’’ Cannon (10) in his
paper on hybrid cotton shows quadripartition in figure 14. In
figure 16 he shows division taking place between two nuclei by a
broad cleavage furrow; no fibers or cell-plate are shown in the
cytoplasm. Of the process he says, ‘“‘Indentations appear in the
periphery of the cytoplasm and midway between the nuclei, which
deepen into constrictions, and finally accomplish the separation
of the nuclei and the formation of the tetrads.’’ He, however,
does not discuss the existence of a cell-plate.

The figure which best indicates quadripartition by cleavage
furrows is that of Beer (50) on Crepis; unfortunately this is un-
accompanied by description. He reports quadripartition in
Matricaria Chamomilla and Crepis taraxacifolia. Three figures of
the latter and one of the former indicate this. In Crepzs the
mother-cell-wall is slightly thickened, and the nuclei are appressed
to the plasma membrane before the cleavage furrow is well de-
veloped. No cell-plate is shown; but figures 57 and 58 show a
constriction at different stages of development. The relation of
the mother-wall to the furrow is not shown. ‘Tahara (69) in his

284 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

figure 9 shows that the mother-wall in Crepis is about one four-
teenth of the diameter of the cell, just before quadripartition
occurs. In Ipomoea Beer (5a) shows the mother-wall very much
thickened after the homoeotypic division. He says that this
wall gives a reaction to tests for callose and pectose, but does not
discuss the cytokinesis. In Oenothera he says the mother-wall
dissolves in I per cent NaOH only after about 24 hours. It is
not soluble in strong phosphoric acid. It stains with Bismarck
brown, methylene blue, and fuchsin. He therefore concludes it
is a modified form of callose or pectose. He says of division that
‘‘Septa are developed which form an extension of the mucilaginous
mother-cell-wall.’’ Gates (23), however, diagrams a cell-plate in
his figure 47, though he does not discuss the process in his paper
on Oenothera.
II]. MATERIAL AND METHODS

The greater part of the work here reported has been done upon
the pollen-mother-cells of Nicotiana Tabacum. In addition ob-
servations were made for comparison upon the pollen-mother-cells
of Primula sinensis, Tropaeolum majus, Ambrosia artemisiaefolia,
Chrysanthemum frutescens, and Helianthus annuus. The root-
tips of the last-named were also studied and compared with the
root-tips of the onion and the pollen-mother-cells of Larix and
Lilium.

Both living and fixed preparations of the pollen-mother-cells
were studied. With the exception of the Ambrosia material, the
flowers were collected from individuals growing in the Columbia
University greenhouse. In most cases the stamens were fixed
individually to insure good penetration of the reagents; however,
in the Compositae it was found more practicable to treat the entire
flower.

The material was fixed in Flemming’s chromic-acetic-osmic solu-
tions in the weak, medium, and strong proportions. The following
reagents were also employed: Merkel’s; picro-formol; Wilson’s
sublimate acetic; and Benda’s solution. The strong Flemming’s_
formula was found to be the most satisfactory, and had incidentally
the additional advantage of being the same reagent which Timber-
lake and Mottier used, thus affording means of more direct com-
parison. The same might be said of Flemming’s triple stain.
While iron-haematoxylin was also used, it contributed little of
value to the study.

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 285

Sections were made for the most part five microns thick. In
some instances, however, it was found advisable to cut them only
three or four microns thick so as to remove all of the superficial
material from median sections of the dividing mother-cell.

To Professor R. A. Harper, under whose supervision this study
was pursued, are due many thanks for his valuable suggestions and
criticism, which are deeply appreciated.

IV. OBSERVATIONS ON LIVING MOTHER-CELLS

The study of living material is without doubt a very valuable
method in cytological research. So far as the more obvious facts
of cell division are concerned, such studies give unimpeachable
data, as is evidenced by the accuracy and suggestiveness of the
studies of such early cytologists as Naegell, Pringsheim, and
Hofmeister. Lundegardh and others are certainly pursuing a
wise course in devoting a large amount of attention to the living
cells.

The chief difficulty in the study of living cells lies in the fact
that they can be retained in their normal condition for so short
a time. In this respect the students of animal cells are more
fortunate, since body-fluids may be used to keep the cells alive
almost indefinitely. The pollen-mother-cells of the larch are found
to break down within ten or twelve minutes after crushing out the
content of the anther into tap water. Even before this time has
expired, and often almost immediately, the nucleus appears to
enlarge, doubtless due to a decrease in the osmotic pressure of the
medium. The introduction of a trace of weak alkali was found to
prolong the period of normal appearance to between fifteen and
eighteen minutes. The pollen-mother-cells of Tropaeolum, Chry-
santhemum, Helianthus, and Nicotiana were studied in the living
condition. This was attempted with Primula; but here the
mother-cells were apparently bound together so firmly that the
entire content of the pollen-sac remains intact during the process
of crushing out, and to separate the cells would involve so much
abuse of the protoplast as to make the results of no value. In
the other dicotyledons noted, the mother-cells readily wash out
separately from the anther as soon as itis cut. In these forms the
protoplast retains its natural appearance longer than in the larch.
This may perhaps be attributed to the enormously thickened

286 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN >

mother-wall. The relative thickness is all the more striking
when it is remembered that the mother-cells of the larch have a
diameter two or three times that of these dicotyledons. The
thickness of the mother-wall in the larch is usually less than one
tenth of the diameter of the protoplast; whereas in the other forms
it is usually more than one third of the diameter of the protoplast.

In the larch the mother-cells seem to pass through the reduction
divisions in about forty-eight hours. The wall thickens slightly
during the first division; but those of adjacent cells do not cohere,
and they separate readily. The various stages in the divisions
can be quite easily identified. The nuclei, chromosomes, and
very often the spindle fibers are plainly distinguishable. One
of the very evident features is the centrifugally forming cell-
plate. The cell-plate can be progressively followed from its
incipiency as a little streak in the equator, until it reaches the
plasma membrane upon either side. It is frequently attached to
the plasma membrane upon one side, while it is as yet incom-
pletely developed upon the other. There is no evidence that the
plasma membrane proceeds inward either in the form of a con-
cavity or a sharp furrow to meet the cell-plate, the division of
the cytoplasm being apparently entirely a function of the latter.
However, after the cell-plate is complete, a sharp furrow does
appear at its juncture with the plasma membrane of the mother-
cell. The formation of this furrow has been referred to by Stras-
burger as a rounding-up process. Just what is its relation to cell-
division is not entirely clear. In the entire process of cell-division
in the broadest sense of the word, there are involved at least four
distinct processes: the division of the nucleus, the formation of the
cell-plate, the formation of the new plasma membranes, and the
formation of the new cross-wall.

In Nicotiana the presynaptic mother-cells (FIG. 1) are angular in
form, the lateral walls being rectilinear in section, and scarcely, if at
all, thickened more than are those of the ordinary vegetative cells.
The corners, however, are thickened so as to appear in section
somewhat like those in collenchyma tissues, though no signs of
laminations, such as Pringsheim reported, can be found either in
the living or fixed material. The mother-cells when teased out
in a drop of water may be seen at this stage to be rarely isodia-
metric, but are usually longer in one dimension than in the others.

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 207

During synapsis the more or less sharp angles become rounded off,
so that the cell approaches more nearly to an ellipsoid or ovoid
form. At the same time the mother-wall may be seen in crushed-
out material to have developed a considerable thickening at either
end of the cell. It is frequently noticeable that the mother-wall is
flattened on one side parallel to the longitudinal dimension. This
flattening may even be so marked that the central optical section
appears triangular, or the apex of the triangle may be truncated.
When two cells lie contiguous to each other, their flattened faces,
which represent the bases of such triangles, are often seen in living
material to lie appressed to each other (FIG. 4); and it is at least
suggested that this line of contiguity may mark the plane of the
last preceding mitosis. Pairs of mother-cells, in which the proto-
plasts have completely divided into the microspores, may even
be found in this relation (FIG. 14), the mother-wall retaining its
original form.

The nucleus is seen to undergo progressive enlargement during
the stages of presynapsis and of synapsis proper. Lubimenko and
Maige (40) believe that this is carried to the point of bursting of
the nuclear membrane. No evidence of the latter phenomenon
was observed in the present study. Sometimes the nucleus would
swell and burst, thereupon completely collapsing, but this was
thought to be due to the abnormal medium in which the cells had
been placed.

The wall continues to thicken during synapsis, and upon the
advent of diakinesis (FIG. 2) it is thicker on all sides, but is still
more markedly so at either end. The nature of the process of
thickening of the cell-wall will be discussed under the observations
on fixed material. The heterotypic spindle may lie either in the
longitudinal axis of the mother-cell (FIG. 21), or transverse to it
(FIG. 3). As the homoeotypic division takes place (FIG. 4) the
wall becomes quite uniformily thickened on all sides. The
homoeotypic spindles are frequently at right angles to each other,
though they may be at a much smaller angle. After the re-
organization of the daughter nuclei there appear occasionally in
the living material a few central spindle fibers; though these are
difficult to make out. One instance (FIG. 4) was found in which
quite a definite row of granules might be seen in the plane midway
between the nuclei. The whole cytoplasm, of course, appears

288 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

very granular in the living material, and it could‘not be determined
whether the granules in question had any specific relation to divi-
sion. The failure to find further evidence of these granules after
studying a great number of living cells, makes one doubt their
relation to cell-division. That such rows of granules might appear
in any part of the cell is indicated by the evidence from fixed
material presented below.

After the homoeotypic mitosis the protoplast assumes a spheri-
cal form within the cell-wall, which conforms to the protoplast on
its inner surface, but which may have an outer surface of various
forms. It would appear that the mother-cell-wall is of such
viscosity as to yield to the pressure due to the cell-turgor, but
that is has too high a coefficient of viscosity readily to assume a
spherical form itself when freely suspended in water. As Hof-
meister suggests, there may be a difference in the viscosity of the
inner and outer layers of the wall, so that the one takes the form
of the enclosed protoplast, while the other retains some of the
effects of the external pressure under which it existed within the
pollen-chamber. In other words, the outer portion of the cell-
wall has an elasticity which operates against its external form
being permanently changed by the application of transitory
pressure.

When the daughter nuclei become completely re-organized they
withdraw as far as possible from each other in the cell, usually as-
suming a tetrahedral arrangement. Soon the cell-cavity becomes
lobed (FIG. 5). It seems that this is not the consequence of the
protrusion of the plasma membrane in the region of each nucleus,
as Farmer and Moore (17) described for similar cells of Aneura;
but it appears rather that it is due to furrowing of the plasma
membrane along the plane midway between each pair of nuclei.
The first indication of the furrowing is to be found in the flatten-
ing of the protoplast on four sides, each of which is parallel to the
plane of three nuclei, so that the entire protoplast assumes the form
of a tetrahedron, the nuclei lying near the corners. A depression
appears in the center of each flattened surface, and the depression
of each face is connected with that of each of the others by a
furrow which bisects the edge of the tetrahedron across which it
passes. ‘These furrows may either take the form of a broad con-
cavity with smooth curves, equaling in width about one half of

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 289

the length of one edge of the tetrahedron, as is shown on the upper
side of FIGURE 6; or they may be more abrupt, as indicated on
the lower side of the same drawing. In no case was the inner edge
of the furrow found to be sharp. In cells in which the protoplast
has collapsed and shrunken into a smaller ball, the wall retains
the form which it had at the time that the collapse occurred
(FIG. 7). In such cases the appearance is as of ridges on the inner
surface of the mother-cell-wall. The presence of these ridges in
the fresh living material and their persistence, after plasmolysis
has drawn the turgid protoplasm away, demonstrates that they are
in no sense artifacts, or related to plasmolysis in any way, but
that they actually occur in the division of the cell.

The furrowing of the plasma membrane and the simultaneous
invagination of the mother-wall take place more rapidly at certain
places than at others. It is evident that if there are four nuclei
arranged tetrahedrally and equidistant from each other within a
sphere, there will be four points upon the surface of that sphere
which are equidistant from each of three of the nuclei. These
points are the centers of the faces of the tetrahedron above de-
scribed. By the transformation of the sphere into the tetrahedron
the plasma membrane has been brought closer to the nuclear
membrane. At these four points above mentioned on the plasma
membrane the constriction of the mother-cell continues to
proceed more rapidly than elsewhere. Thus there are formed
four projections of the inner surface of the cell-wall which are
equidistant from each other, one being in the center of each
face of the tetrahedron, and which are connected with each other
by a ridge of less magnitude. These projections, or invaginations,
continue to elongate toward the center of the “cell, and conse-
quently in the direction of the fourth nucleus, keeping at all
times equidistant from the three nuclei. As a result the four
projections meet in the center of the tetranucleate cell, and fusion
of their tips occurs (FIG. 8). Thus there are organized four
protoplasmic masses each with a single nucleus and connected
with each of the other four by an isthmus of cytoplasm, at first
quite broad. It is evident that there would be six such isthmuses,
not more than three of which would show in any one optical
section.

Apparently each isthmus constricts independently of the others.

290 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~-

Many stages may be found showing different degrees of this con-
striction (FIGS. 9, 10, 12). The daughter-cells are not at first
spherical. This may be related to the resistance of the thick
mother-wall to transformation of form, or to the unequal rates at
which the isthmuses narrow (FIG. 11). Upon the completion of
the division each of the four cells is separated from each of the
other three by a lateral wall which is thicker in its periphery and
thinner at its center. Its form persists even after the protoplasts
undergo plasmolysis (FIG. 13). Since in living cells the protoplast
completely fills the space enclosed by the cell-wall, it will be seen that
the daughter-cell is not perfectly spherical, but rather has in section
the form of an ellipsoid. Such a condition is shown to the right in
FIGURE 14. To the left, however, are cells which have proceeded
a step farther and have approached the spherical form. Later
(FIG. 15) the cells become exact spheres. This last change is
accompanied by their enlargement and a decrease in thickness of
the mother-cell-wall. The latter may involve a dissolution of
the inner portion of the cell-wall. The entire cell does not retain
its initial outline at this time, but assumes more nearly that of a
tetrahedron; the division of the single spherical protoplast into
four spherical protoplasts and the growth of the later has involved
a considerable increase in the total volume, which has doubtless
led to a stretching of the outer portion of the mother-wall. As
the exine of the spores appears this mother-wall becomes thinner
and thinner and finally disappears entirely.

From a study of the living material it has been shown that
normally the mother-cell of Nicotiana thickens its walls during
synapsis and the heterotypic karyokinesis, that no division of the
cytoplasm occurs after the latter, but that the homoeotypic karyo-
kinesis takes place almost immediately and is followed by a divi-
sion of the tetranucleate cell into four uninucleate spores. This
division involves a furrowing of the protoplast in the planes mid-
way between the nuclei. It is not possible in the living material
to determine the relation of cell to cell within the tissue, nor to
study critically the details of the process of division.

V. THICKENING OF THE MOTHER-WALLS
In the fixed material it is found, as noted above, that the
mother-wall begins to thicken during synapsis, commencing first

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 291

at the corners, especially at the ends of the cell (F1G. 20). It is
here thickened to a maximum degree of 1.4 microns, though the
greater part of the thickened portion is about 1.05 microns in
thickness. The mother-cells are arranged in the pollen chamber
in general in two plates, lying side by side. The individual cells
are usually elongated transversely to these plates, so that the
one end of each mother-cell abuts upon the tapetal layer and the
other upon the intercellular spaces between the two plates. It is
as if the mother-cells mutually compressed each other, causing
this modification of form, and permitting the thickening of the
wall at first only at the points of least pressure.

In diakinesis the mother-wall is much more thickened. It may
even reach a maximum of 7 microns, which is nearly as thick as it
ever becomes. Usually, however, the thickened portion of the
cell-wall in diakinesis has a maximum of about 4.2 microns, and
its average thickness is about 2.8 to 3.5 microns. It is usually
thickened throughout about one half of its area. In the early
anaphases of the homoeotypic division the ends of the mother-
cell are thickened to from 4 to 6 microns, and the lateral faces
about 2 microns. The thickest portion of the wall at this time
comprises about three fourths of its area. In the late telophases,
however, the entire wall becomes almost uniformly thickened, so
that it becomes difficult to determine the original longitudinal
axis of the cell (FIGS. 24, 25). After re-organization of the daughter
nuclei the wall appears thickened all around (FIG. 26), but there
are variations in the degree of thickening which are not uniformly
distributed. From the way the cells fit together in the pollen
chamber it seems reasonable to conclude that the variations in
thickness are related to the association of the mother-cells and
their mutual pressure, etc., rather than to the composition of the
mother-wall.

The absence of lamination or other visible differentiation in
the mother-cell-wall indicates that the thickening process is not a
growth by intussusception or apposition, but merely a swelling or
gelatinization of the secondary strata of the mother-cell-wall.
The wall appears perfectly homogeneous and stains a deep orange.
A survey of the substances which stain orange in the cytoplasm
leads one to the conclusion that they are often transitional forms
of carbohydrates. Denniston (12) found an orange zone about

292 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

the starch grains and attributed such a constitution to it. The
orange zone which Timberlake found preceding the advent of the
cell-plate is very likely composed of carbohydrate which was
perhaps in the process of polymerization from a soluble sugar of
low molecular weight through the less soluble dextrins, etc. and
ultimately into cellulose. The orange-staining bodies in the
cytoplasm of so many plant cells may possibly also be carbohy-
drate material of varying degrees of polymerization.

The history of the mother-cell-wall also indicates that during
reduction it may be passing through transitional stages leading
ultimately to its dissolution and disintegration. In most plant
cells the mother-cell-wall persists after mitosis and becomes a
part of the cell-wall of each daughter cell. The wall of the pollen-
mother-cell, however, like that of other spore-bearing structures
disappears as an entity, while the walls of the daughter cells
are constructed entirely anew within the mother-cell. As has
been shown above, the mother-wall beginning at the time of
synapsis continues to thicken to a marked degree during the re-
duction divisions, and finally dissolves. It seems hardly possible
that this thickening of the mother-cell-wall can be in the nature
of growth, such as doubtless does occur in the formation of so
permanent a structure as the exine, for example. Chemically
considered this thickening of the mother-wall is probably in the
nature of a colloidal swelling or hydration. Fischer (19) has
recently attempted to demonstrate that hydration is not a stage
in the process of solution as it has usually been considered. Though
it may be that solution is not an absolutely necessary consequence
of hydration, it is still true that very often, if not usually, solution
does follow hydration. There is at least this much of a sequence in
these cases; and solution involves a greater increase in colloidal dis-
persity than does hydration. It, therefore, does not seem illogical
to conclude that the thickening of this mother-cell-wall is in the
nature of an increase in colloidal dispersity of the substance of the
wall, which process continues, and ultimately leads to such extreme
dispersity that an entire dissolution of the mother-wall ensues. In
addition to the cases of thickening of the mother-wall noted in the
table below, Wille figures (81) this condition in 14 dicotyledons.

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 293

VI. THE CENTRAL SPINDLES

After the heterotypic karyokinesis the central spindle persists
connecting the two daughter nuclei (FIG. 21). Fibers may be
found running apparently the entire distance from one nucleus
to the other; they are attenuated near their ends, giving the
appearance of their being thickened throughout about one half
or two thirds of their length in the central region. Careful
examination, however, leads one to conclude that the fibers do
not pull away from the nuclei. Scattered about in the cytoplasm
are a few red-stained bodies, three of which are shown in the
drawing. The hyaline area about each is probably an optical
illusion due to diffraction. Comparison of this stage with a similar
one in the dividing cells of the onion root-tip reveals the fact that
in the latter the spindle fibers are somewhat more thickened
throughout one half of their length in the central portion, and a
very distinct orange zone and cell-plate have already begun to
form in the equatorial region of the spindle. In the mother-
cells of Nicotiana, however, no orange zone appears across the
equator, and no blue-stained plate is developed. The fibers
(FIG. 22) continue to become more arched, as the mother-cell
approaches more and more the spherical form, and the rather
rudimentary spindle takes on a more inflated aspect. The peri-
pheral cytoplasm perhaps appears to be now more fibrillar; fibers
run out from the nucleus in all directions to the plasma membrane
and frequently cross along the surface of the spindle. There is
no evidence that these crossing fibers become transformed into
peripheral spindle fibers. In the later stages the fibers of the
central spindle proper seem not infrequently to cross each other,
whereas earlier (FIG. 21) such a condition was quite exceptional.
It is difficult to state how this is brought about. There are
apparently, however, many more fibers present in the cytoplasm
in the later stages than immediately after the heterotypic karyo-
kinesis.

The longitudinal axes of the homoeotypic spindles, as was
observed from the study of living material, are frequently at
right angles to each other (FIG. 23). By the time the metaphases
of the second division have been reached, the heterotypic spindle
has entirely disappeared. The cytoplasm presents a densely
granular structure with evidence neither of alveoli nor of fibers;

294 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the only kinoplasm present is the very distinct fibers of the spindles.
The granules appear to be aggregated into more or less spherical
groups (FIG. 24), which give almost a flocculent appearance to the
cytoplasm. In addition there are scattered about many red-
stained granules, which are about one eighth of the diameter of
the chromosomes and have no special arrangement.

In the mother-cells of Nicotiana, when the daughter nuclei
have become fully organized (FIG. 26), there is found a spindle
between each pair of nuclei, that is, there are six spindles. These
spindles are indistinguishable from each other, in other words it
is not possible to tell either from the nuclei or from the spindles
which of the four nuclei are sister nuclei. There must be then a
disappearance of the homoeotypic spindles and the organization
of six new spindles from the cytoplasm, or the former persist and
there are organized four new spindles which are indistinguishable
from them. As far as could be determined, the latter is the pro-
cedure in this form (FIGS. 24, 25).

Before the nuclear membranes are formed, the six spindles have
become organized and are indistinguishable. The individual
fibers are straight and parallel, the spindles not taking on the
inflated appearance until about the time of the formation of the
nuclear membranes. At first the fibers appear rather attenuate
at their ends, as in the homoeotypic division; but very soon (FIG.
26) they are quite uniform throughout, at least there is no zonal
differentiation. The fibers run from each nucleus to the others
and to the plasma membrane as well. Were it not for the arching
of the peripheral fibers of the spindle, it would almost seem as
if the fibers radiate in all directions from the nuclei, and that the
spindle is more or less an incidental and unavoidable consequence.
It seems quite likely, however, that the spindle should be recog-
nized as a special structure, though the other fibers, as far as the
evidence goes, are of similar composition and character. In
FIGURES 26, 27, and 28 the attempt was made to show all the fibers
in the section, which was five microns in thickness, by changing
the focus progressively during the course of making the drawing.
A similar method was employed by Allen (16) in his paper on Poly-
trichum. It will be seen that the fibers are attached to the nuclei
more or less in bunches or tufts; from a single tuft there may
proceed fibers both to the plasma membrane and to one or more

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 295

nuclei. They rarely, if ever, run parallel or to the same region
on another membrane. Quite regularly these tufts of fibers seem
to be attached to the nuclear membrane just above the chromatic
mass resulting from the transformation of a chromosome. These
chromatic masses are practically all peripherally placed in the
nucleus. It has been several times suggested that the material
of the fibers is of nuclear origin, and this would indicate that the
chromatin may have something to do with their formation or
secretion from the nucleus.

VII. THE CONSTRICTION FURROWS AND NUCLEAR MIGRATION

In the tetranucleate pollen-mother-cell we have a condition
which offers peculiar advantages for studies in nuclear migration,
especially inasmuch as when first formed the nuclei are closely
appressed to the plasma membrane (FIG. 26), whereas after spore-
formation they lie in almost the exact center of the daughter cells.
(FIG. 37). I have studied quite carefully the origin of the tetra-
hedral arrangement of the nuclei. It is by all means the pre-
vailing arrangement in Nicotiana. In the examination of prac-
tically all of the hundreds of mother-cells in a single stamen, only
four could be found which departed from this perceptibly, and
none of these had a perfectly monoplanal disposition. The origin
of the tetrahedral arrangement can not be attributed to the homoe-
otypic spindles, being from the first at right angles to each other.
Probably in somewhat less than 50 per cent. of the mother-cells
are they exactly at an angle of 90° during the anaphases. More
often they have an inclination of from 45° to 60°. However,
when the chromosomes have reached the poles, the four aggre-
gates which they compose are found to be almost invariably equi-
distant, tetrahedrally arranged, and appressed to the plasma mem-
brane (FIG. 25). It is thus just before nuclear re-organization
that the tetrahedral arrangement is finally determined. Giesen-
hagen (24) has written extensively on the orientation of spindles
and division planes, attributing them largely to the polarity of the
mother-nucleus.

As noted, the cell was at first perfectly spherical, but soon the sides
parallel with the spindles appear flattened (FIG. 27), the whole cell
thus becoming a tetrahedron with each of its four faces lying over a
group of three nuclei and parallel to the spindles between them.

296 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

At the middle of some of the spindle fibers at this stage there
appear to be thickenings, but these little masses may also be found
apparently unassociated with fibers. Occasionally one or two
fibers nearer the center of the mother-cell may be found with a
dense granular mass near its middle point. Such sporadic appear-
ances are doubtless responsible for the statements by many
authors that the division is of the ordinary cell-plate type; but
there is no evidence that the fibers shorten at this time or at
any time in the process of division. They are never seen to pull
away from the nuclei and no plate or similar structure across the
equator of the spindle is formed. The fixed material shows no
plasmolysis in these stages, and the red, blue, and orange stains
were well balanced. No difficulties in technique, such as Stras-
burger reports having encountered in the dicotyledons he studied,
were here experienced. In a number of instances rows of granules
were found; but these are as frequently, if not more often, located
in other parts of the cell than the equatorial planes. Such a one
may be seen in the upper left-hand corner of FIGURE 27, in the
lower right-hand corner of FIGURE 28, in FIGURE 30, and in the
lower left-hand corner of FIGURE 32. They are probably in most
cases the result of chance distribution of granules, and only in
three instances, FIGURES 27, 39, and 31, can they be considered
as having any relation to cell-division. The last-named figure
presents the nearest approach to a cell-plate which could be found.
It might be argued that these rows of granules in various positions
between the nuclei are composed of material which is diffusing
from the nuclei to the plane of division, but no accumulation of
such material in that plane in the form of a plate could be found.

A slight depression or concavity appears almost immediately
(FIG. 27) in the plasma membrane at the equatorial plane of the
spindle. At first it is rather abrupt, though the exact center of
the concavity is always a smooth curve and never a sharp edge.
Soon, however, this broadens into a wide smooth curve (FIG. 28),
giving the mother-cell a lobed appearance. Spindle fibers may
run to the plasma membrane in the region of the furrow, but
there seems to be no tendency for them to be oriented thereupon
any more than upon other points along the membrane. The
spindles seem at this time to take on a little more definite organiza-
tion. Not so many fibers are found crossing each other, and the

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 297

individual spindles seem to be pressed together along the line
where they are in contact, each. one being thus quite definitely
delimited. This results in many instances in the appearance of a
triradiate figure composed of bundles of fibers (FIG. 28).

As the furrow deepens to the level of the outer margins of the
nearest two nuclei it again becomes somewhat sharper. Mean-
while the nuclei slowly draw away from the plasma membrane
eee 29). The two edges of the furrow approximate an angle of
go° with each other, but the edge of the furrow is always rounded
(FIG. 30). By this time the spindle has almost lost its inflated
appearance. The peripheral fibers are no longer arched, as in the
earlier stages.

The question as to the relation of the furrowing to the growth
of the plasma membrane is a difficult one. It seems certain that
growth of this membrane must take place at some time during the
process of cell-division. It is not easy to determine whether the
fibers are pushed before the invading membrane in the equatorial
plane, as in animal cells, or whether the middle portions of the
fibers as they successively come in contact with the invading mem-
brane become absorbed in it, the remainder of the fiber between
either nucleus and the new membrane persisting as radiating fibers.
Such a transformation of fibers into plasma membrane would
resemble that described by Harper (280) for free cell formation
in the ascus. The existence of such radiating fibers from the
nucleus to the plasma membrane of the furrows may be found
in all later stages of the division process (FIGS. 30-36). It seems
not improbable that in Nicotiana also the spindle fibers are in
part transformed into the plasma membrane. It is not, however,
by any means proven that this is the only source of new plasma
membrane material; but it is not surprising to find that here as
well as in the cases where the cell-plate is the precursor of the
plasma membrane, we may have the origin of that membrane from
the fibers (kinoplasm) of the cell. As evidence accumulates it
seems more and more likely that this kinoplasmic material arises
from the region of the nucleus; this is then only further evidence
that the material of the plasma membrane has its primary origin
in the nucleus of the cell. The presence of radiating fibers from
all sides of the nucleus to the plasma membrane, not only during
division but as well in the young microspores both those of dico-

298 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

tyledons and of the larch, where in the latter case the division is
by a cell-plate, makes the above interpretation possible whether
it be assumed that the membrane grows by intussusception or
apposition. There is no reason for presuming that the radiating
fibers may not contribute to the growth of the plasma membrane
as well as do the spindle fibers.

Considering the tetranucleate cell with the constriction furrows
(FIG. 30) as a whole, it will be noted that inasmuch as there are
six spindles, no two of which are parallel, there will be six furrows. '
Three of these furrows come together above each point of con-
tiguity of three spindles. In other words, there are four points
on the surface of the mother-cell at each of which three furrows
meet. These points are the centers of the four faces of the tetra-
hedron. Each of these points of intersection is equidistant
from the three nuclei, the mutual spindles of which are bisected
by these furrows. Since the median line of each furrow is the
arc of a circle which is smaller than a great circle of the tetra-
nucleate cell, the points of deepest depression of these furrows are
at their points of intersection, consequently there are four pro-
jections of the plasma membrane into the protoplast. Since the
mother-cell-wall conforms to the plasma membrane exactly, the
condition might be described as four equidistant invaginations
of the mother-wall, each of which is connected with the others
by a ridge upon the inner surface of the wall. These projections
proceed gradually toward the center of the cell, keeping equidistant
from the three nearest nuclei, and growing toward the fourth.
It is thus apparent that these four projections finally meet in the
center of the tetranucleate cell, before the furrows have com-
pleted the division in the equator of each spindle (r1G. 32).

The first indication of the growth of these projections toward
the center of the mother-cell is in the straightening of the spindle
fibers noted above (FIG. 30). This straightening results in the
fibers pulling away, from the center of the mother-cell, leaving a
space which is triangular in section, but is really pyramidal, in
the center of the cell. The eccentric position of the projection
of the mother-wall shown in FIGURE 31 is not typical, and is
doubtless due to the failure to cut all three spindles in the median
plane, the one on the lower right side being cut near the periphery
of the spindle. FIGURE 32 gives the typical condition. The

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 299

projection of the mother-wall is triangular in section, the angles
which are, however, never sharp, representing the edges of the
furrows as they cut into the equator of the spindles. FIGURE 33
shows a section cut through the center of one of the nuclei of the
mother-cell and tangential to two others, showing the projection
of the mother-wall extending in to the center of the cell where it
has fused with those from the three other directions.

By the fusion of the four projections of the mother-wall at the
center of the mother-cell the latter is divided into four uninucleate
protoplasmic masses, each connected with the other three by a
broad isthmus of cytoplasm through which spindle fibers continue
to pass. The furrows continue to deepen, as before, and the pro-
jection of the mother-wall enlarges transversely so that there is a
constriction of the isthmus between each pair of daughter cells.

While these processes are going on, there is simultaneously a
migration of the nuclei away from the plasma membrane (FIGs.
28-37); until at the end of the division the nucleus occupies the
central position in the daughter cell. The conditioning factors
in such migration have, of course, not yet been determined with
certainty; it is, however, interesting to note that should the nuclei
be thought of as bearing electric charges of like sign, they would
behave as described: namely, assume a tetrahedral disposition
before cell-division. And if further we think of the plasma mem-
brane as bearing an electrical charge of sign unlike to that of the
nuclei, the nuclei would ultimately move to a central position in
the daughter cells, in other words to the position of equilibrium,
considering that they bear charges unlike that of the plasma
membrane.

The tetrahedral arrangement of the nuclei, and consequently
of the microspores, seems to be the prevalent disposition among
dicotyledons and, in fact, among all of the higher plants, especially
those in which quadripartition has been found. Below is given a
table, showing certain data on this point given in the literature.
Of the forms studied in this investigation the predominant dis-
position in all is tetrahedral, though Chrysanthemum shows a
greater diversity in this respect than any of the other species
It will be seen that out of 50 forms of bryophytes, pterido-
phytes, and spermatophytes which have been studied in this
respect, 40 are reported to have the tetrahedral arrangement; in

300 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

only 19 have the nuclei been noted in the form of a rhomb
or square; four forms occasionally show pyramids, and in three is
found the arrangement in a single row. Of 42 forms which have
quadripartition, 37 have the tetrahedral and 11 the rhomboidal
or rectangular arrangement; none of these are reported to have
the nuclei or spores arranged in a pyramid or row. It will thus
be seen that the tetrahedral arrangement is by far the predominant,
and the arrangement of the cells in pyramids or rows the most rare.
The rhomboidal and rectangular disposition occupy intermediate
relations, but the data have not been accurately enough recorded to
determine which of these later is the more frequent. Hofmeister,
Berthold, and Errera early contributed observations on the adjust-
ment of the plasma membrane to Plateau’s law of minimal surface;
and Thompson (72) has recently called attention to this work, ex-
pressing the relation that (p. 424) ‘‘ina complex system of films . . .
three partition-walls and no more meet at a crest, at equal angles.”’
Harper (28e) in his study of Gonium colonies has laid particular
stress upon the tendency of cells to group themselves in threes.
He finds a tendency in the four-celled stage to shift from a rect-
angular monoplanal arrangement to that of a rhomb, wherein
two of the cells opposite each other are closer together than the
other pair, but in the older colonies the central four cells usually
take the arrangement of a perfect square partly on account of the
tension from the peripheral cells of the colony. This tension may
be the consequence of the tendency for the peripheral cells to form
groups of three with the central cells. The law of least surfaces
certainly applies also to these mother-cells in quadripartition.
It is evident that in the pyramidal arrangement of four spores in
one plane there is one group of three, in the rhomboidal there are two
groups of three, and in the tetrahedral there are four groups of
three. It is apparent that if a surface be described about four
spheres of equal size in such a way that it is tangential to the
surface of the included spheres which are in contact with it, the
extent of this described surface will vary with the arrangement
of those spheres in the following descending order: linear, pyra-
midal, rectangular, rhomboidal, and tetrahedral. If then the
mother-cell-wall is exerting a force of compression upon the four
spores and the latter adhere closely together, we would expect
to find the tetrahedral arrangement of the spores to be the

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 301

most common. This is, of course, what we have observed
above. But it should be remembered that the tetrahedral
arrangement has been shown in Nicotiana to be determined,
not during the division of the mother-cell, but previously near the
close of the nuclear divisions. It is quite probable then that the
restraining tension of the wall has very little to do with initiating
the tetrahedral arrangement, though it may play a large part in the
maintenance of such orientation. It is quite possible, as noted,
that the appearance of the tetrahedral arrangement is to be
attributed to a mutual repulsion between the daughter nuclei, and
an attraction between them and the plasma membranes. It may
be also that the movements of the plasma membrane in forming
the furrow during cell-division, as described above, are in part
at least an expression of this same force of attraction between it
and the nuclei.

Each isthmus of the single mother-cell does not necessarily
constrict at the same rate as the others (FIGS. 34, 35, 36). The
division may, in fact, be entirely completed between two nuclei,
before the isthmus between others has fairly begun to narrow.
As the division proceeds the two sides of the same furrow come to
lie more nearly parallel (FIG. 35), resulting in each of the daughter
cells approaching more nearly to the spherical form. It is quite
likely that this narrowing of the furrow is, in fact, to be attri-
buted to the surface tension of the daughter cells. The portion
of the surface of mother-cell over each nucleus, however, retains
the form of an arc with a longer radius, indicating that the
mother-wall is quite resistant to the rounding up process.

As division is completed, there is quite a definite system of
radiating fibers in the cytoplasm (FIG. 36), running from the
nuclear membrane to the plasma membrane and quite evenly
distributed over the latter. Finally, however, the cytoplasm
returns to the reticular appearance which it bore at the beginning
of synapsis (FIG. 37), and the spores lie imbedded in the mother-
cell-wall as a sort of matrix while the spore-coats are being de-
veloped.

VIII. OTHER DICOTYLEDONS

In the five other dicotyledons studied, the process of cyto-
kinesis in the pollen-mother-cells was found to agree in all general
particulars, as far as studied, with that in Nicotiana. In view of

302 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

this fact, together with the large amount of collateral evidence
presented in the review of the literature given, it seems quite
probable that in a majority if not in all of the dicotyledons in
which quadripartition of the pollen-mother-cells occurs, there is
a division of the cytoplasm by constriction furrows, as above
described for Nicotiana, without the development of a true cell-
plate.

In Helianthus there is a greater number of blue-stained granules
irregularly distributed throughout the cell at about the time of
the beginning of the invagination of the mother-wall. They
also frequently appear to be in chains, but these may lie either in
or out of the equatorial plane. No evidence was found of these
granules being arranged in the form of a plate. The same thick-
ening of the wall occurs as in Nicotiana.

In Chrysanthemum frutescens a large number of irregularities
occur as to number of pollen-grains formed from a single mother-
cell. There sometimes appears to be only one, no division of the
mother-nucleus taking place. In other cases, two, three, four, or
five nuclei may be present and as many spores may be formed,
respectively. When five are present they may all lie in one plane
with one nucleus in the center and the other four at equal distances
about it. In such cases there are eight spindles. The tetrahedral
arrangement is, on the whole, less frequent in Chrysanthemum
than in Nicotiana. ‘The size of the respective nuclei in the mother-
cell also varies. Sometimes it appears as if a nucleus was organized
from a single chromosome, and several instances of very small
pollen-grains have suggested that these might be later stages of
such an aberrant development as Juel found was the case in
Hemerocallis. A study of nuclear division in Chrysanthemum
would doubtless lead to interesting results. The cell-division of
the pollen-mother-cells appears to be as described above for
Nicotiana. This last statement may also be made for the other
member of the Compositae that was studied, namely Ambrosia
artemisitfolia.

The author is able to confirm the statement of Miss Digby that
constriction occurs in Primula. No evidence of a cell-plate was
found. The isthmus between the nuclei in the later stages takes
the form of a narrow neck, the daughter cells being farther
apart than in Nicotiana. With regard to Tropaeolum, mother-

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 303

cells were found which confirmed the figures of Strasburger with
respect to the row of granules in the equatorial plane; but rarely,
if ever, were they as prominent as his drawings show them, and
they are arranged in chains and not in a plate. Furthermore,
other mother-cells were found which contained no such chain of
granules, or, if one was present, it lay in another part of the cell.
The hourglass-like figures which appear in Primula were also
noted in Tropaeolum. No evidence of a true cell-plate was found.

There is in these pollen-mother-cells no indication of a centrif-
ugally formed continuous cell-plate such as is so conspicuous in
the pollen-mother-cells of the lily and the larch and in vegeta-
tive cells of the higher plants. The central spindle is poorly
developed and there is no shortening of its fibers. But the fact
that we have here, as in cell-plate formation, the close association
of the fibers with the formation of the plasma membrane, points
to the importance of the study of these structures in their relation
to the phenomena of cell-division.

Further studies are contemplated, involving a wide range of
species and extending to the nuclear phenomena incident to
quadripartition.

IX. DiIscussIoN

The existence of a form of division by furrowing in certain cells
of the higher plants suggests the possibility of ultimately harmon-
izing the usual division by cell-plates in these forms with the
division by so-called constriction in the higher animals. As
noted above, there are in the lower plants and animals also types
of cell-division more or less intermediate between these two
extremes; and it seems highly probable that the processes involved
in these essential phenomena of cellular reproduction are deter-
mined by the fundamental physico-chemical properties of the
complex colloidal protoplasmic mass. The fact that in many cases
of quadripartition, as described above, there is a gelatinization of
the cell-wall just prior to the division of the cell by furrows indi-
cates that the cell-wall may be an important factor in controlling
such form changes as occur in division by furrows. This only
emphasizes the contention that botanists have no right to con-
sider the protoplast alone as the cell. The growing and dividing
cell of the higher plants should be thought of as a unit comprised
both of protoplast and cell-wall. It is certainly a striking fact

304. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

that these pollen-mother-cells whose walls become a gelatinous
matrix, like that present in so many animal cells, especially eggs,
and whose protoplasts assume a spherical form like the egg cells of
many animals, divide in a fashion quite analogous to that of the
latter: namely, by a centripetal furrowing of the cytoplasm with-
out the formation of a cell-plate.

The occurrence of the various types of division of the spore-
mother-cells of the higher plants, as shown by the data thus far
accumulated in the literature, is indicated in the following table.
It must constantly be remembered that much of it is introduced
incidentally to other investigations and is based on fragmentary
evidence. With this in mind the evidence as to quadripartition,
arrangement of spores, and thickening of the wall, presented by
the early cytologists, who had these things definitely in mind, are
quite as dependable as the isolated statements of more recent
workers.

Cell division in mother-cells

PLANT ARRANGEMENT PaArTITION Division BY AUTHOR MOoTHER-WALL
Aneura tetrahedral _ bi- cell-plates Farmer & Moore
. quadri- te s Farmer
Pellia - bi- iS 4 ey thick
a se quadri- i i Strasburger
Fegatella rhomb “ rk + Farmer
Pallavicinia tetrahedral * io fa
Anthoceros x 43 furrowing Hofmeister
- : - cell-plates Strasburger
s 2 - (?) Davis
Funaria 2 3 Sachs
Pteris “ - cell-plates Calkins
Osmunda - Es - a Smith
Botrychium re * : _ Stevens thin
i monoplanal a ie ss . .
Polypodium “ Russow
Equisetum tetrahedral quadri- Russow
a bi- furrowing Hofmeister
* tetrahedral quadri- cell-plates Strasburger thick
: monoplanal + # y a: =.
Psilotum bi- ¥ s %
FS monoplanal furrowing Hofmeister
Isoetes tetrahedral quadri- cell-plates Strasburger thick
Marsilea - rs (?) - he
“: monoplanal be (?) SS i
Ceratozamia * bi- furrow. Juranyi ss
cell-plates
zs tetrahedral “ furrow. " «

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS

PLANT ARRANGEMENT PARTITION DIVISION BY
cell-plates
Zamia st i cell-plates
a: monoplanal ‘“ : x
Pinus
Larix tetrahedral _ bi- cell-plates
o a quadri- a
a monoplanal _ bi- “ “
Monocotyledons
Allium bi- cell-plates
Tradescantia se z
Fritillaria, Lilium, - a
Anthericum a zu 4
Funkia ‘ . ‘
Potamogeton, - oo US
Convallaria ms s
Symplocarpus, sf ie as
Peltandra 2 # am
Trillium a . %
Agave * . ?
Zea a furrowing
Musa tetrahedral ‘“ (?)
ao rhomb, row, (?)
se square, etc. . ‘ (2)
Neottia - no cell-plates
Orchis y ie bs =
Cypripedium s
Epilobium cell-plates and
furrowing
Carex cell-plates
Hemerocallis incomplete ‘ ss
Naias quadri-
Tris furrowing
Orchids monoplanal > cell-plates
Sisyrinchium tetrahedral “
Aloe, Ixia, Freesia, *
A picra 7
Monbretia, Gasteria,
Haworthia y
Asphodelus .
Epipactis bi- cell-plates
Potamogeton pyramid
Dicotyledons
Asclepias row bi- cell-plates
Ceratophyllum tetrahedral ‘“ s -
e monoplanal ‘“ a :
Rafflesia tetrahedral ‘“ bi e
“ monoplanal ‘ - e

AUTHOR

Treub
Hofmeister
Timberlake

“ec

Pringsheim
Hofmeister
Strasburger
Sachs
Wiegand

Duggar

Atkinson
Schaffner
Kuwada
Tischler

“ie

Hofmeister

“cc

Guignard

Tschistiakoff
Juel

Hofmeister

“ec

Guignard

Strasburger
Wille

Strasburger

“ic
“ce

Ernst & Schmidt

ae 4é

395

MOTHER-WALL

thick

medium

306

PLANT
A pocynum

Passiflora
Taraxacum
Hieracium
Momordica
Mirabilis
Aristolochia
Acacia

Lathyrus
Nymphaea

Podophyllum

Syringa
Bignonia
Lavatera
Cobaea
Cucumis

Cucurbita, Bryonia

Oenothera

Althaea

Tropaeolum

Ribes

Hesperis, Pisum
Lathyrus, Ipomoea

Dahlia
Drosera

FHieracium
Daphne
Taraxacum
Convoloulus
Houttuynia
Passiflora
Vicia
Primula

row, pyra-

mid, square

rhomb,
tetrahedral

square,
pyramid

tetrahedral
rhomb

rhomb
tetrahedral
tetrahedral

tetrahedral

tetrahedral
square
tetrahedral

tetrahedral
tetrahedral,
rhomb

tetrahedral
rhomb,
tetrahedral
monoplanal
tetrahedral

tetrahedral

ARRANGEMENT PARTITION DIVISION

quadri-

cell-plates
(?)
(?)

no cell-plates

furrowing

(?) cell-plates

ae ae

(?)
cell-plates
(?)
furrowing
cell-plates at
times

cell-plates
(?)

(?)

cell-plates

cell-plates and

furrowing
furrowing

no cell-plates

ae ae ae

furrowing

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN™

AUTHOR

Frye & Blodgett

ae ae

Hofmeister
Osawa
Rosenberg
Wimmel
Tischler

thick

Samuelsson
Rosanoff

Gregory

Lubimenko & Maige
Mottier
Juel
Duggar
Byxbee
Lawson thin
Strasburger
Naegeli
Gates
Naegeli
Beer

von Mohl
Wimmel
Pringsheim

ae ae

Strasburger

Sachs

(see above) thick
Tischler

Baranetzky

Ishakawa

Rosenberg thick
a thin
Osawa

Wimmel thick

Shibata & Miyake

Hofmeister thick
Fraser
Digby thick

(see above)

MorTHER-WALL

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 307

PLANE ARRANGEMENT ParTITION Division BY AUTHOR MOoTHER-WALL
Sarracenia re y Nichols
Gossypium s is Cannon
Crepis tetrahedral 7. Beer thick
Hamamelis By a i Shoemaker
Parnassia * "4 a Pace -
Nicotiana rhomb,

tetrahedral s “ (see above) 4
Chrysanthemum tetrahedral - - _ is Hs
Ambrosia ce fe * 7‘ *
Helianthus = ‘ ia “ FS

It will thus be seen that quadripartition has been reported in,
at least, 32 dicotyledons, 11 monocotyledons, I gymnosperm,
6 ferns, I moss, and 5 liverworts. _ Bipartition in the spore-mother-
cells has also been reported in each of these groups, except the
mosses; but only 12 cases are noted in dicotyledons, and 18 in
monocotyledons. Quadripartition by cell-plate formation has
been reported most abundantly in the liverworts, due largely to
the work of Farmer, and in the ferns. Nine cases have been re-
ported among the dicotyledons; they are: in Oenothera by Gates,
in Podophyllum by Mottier, in Syringa by Juel, in Lavatera by
Byxbee, in Cobaea by Lawson, in Bignonia by Duggar, in Althaea
by von Mohl and by Wimmel, and in Cucumis and Tropaeolum by
Strasburger. The statements by the writers of some of these
papers as to the presence of a cell-plate have been seriously brought
into question by more recent work on the same plants. The
other papers give no figures which in any way demonstrate the
presence of a cell-plate in these divisions. Their evidence consists
entirely of statements without confirmatory description or figures,
and in view of my results on Nicotiana can not be accepted as
final evidence. On the other hand, there is more or less evidence
that quadripartition occurs by furrowing and without a cell-
plate in 21 dicotyledons. In 18 dicotyledons quadripartition is
reported as accompanied by a thickening of the mother-wall.
In none of these has a cell-plate been demonstrated beyond doubt.
In fact, no case has been proven in any plant, so far as the present
survey of the literature goes, in which quadripartition by cell-
plates has been found in a cell with a greatly thickened mother-
wall. The nearest approach to this is given in Strasburger’s

1 The data in the last column are based upon the authors’ drawings respectively,
measuring from the outer boundary of the cell wall to the protoplast.

308 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

study of Equisetum and Jsoetes, done at the same time as that on
Tropaeolum, and presenting the same evidence, which in the light
of the observations recorded above, must be regarded as doubtful.

We are forced to conclude with Guignard then, as against Dippel,
Samuelsson, and others, that quadripartition and bipartition may
occur in either monocotyledons or dicotyledons. Furthermore,
there is no doubt that cell-plates occur in the bipartition of the
pollen-mother-cells as well as the vegetative cells in both mono-
cotyledons and dicotyledons. We have seen that the wall of the
pollen-mother-cell may be thickened in members of either one of
these groups. So that there seems to be no evidence that these
two groups of flowering plants differ in general in any way in
their mode of microspore formation.

Since so little is known of the dynamics of cell-activities of
any kind it is very difficult even to attack the question as to
what physico-chemical processes are involved in cell-division.
However, it is to be hoped that the discovery of a closer relation
between the two diverse types of cell-division: that by furrowing,
characteristic chiefly of animal cells, and that by cell-plate, com-
mon to higher plants, will help to bring to view a new standpoint
from which the physiological processes of cell-division may be
more effectively studied.

The almost infinite complexity of protoplasm has been so often
emphasized that it need not be further mentioned here. In
addition to the great variety of chemical compounds in the cell,
these exist in all sorts of physical states. There are’ particles in
suspension, and substances in true solution; and between these
two extremes there are substances in all possible degrees of dis-
persity, including suspensoids and emulsoids, making up the col-
loidal mass of protoplasm. Not only is there an almost infinite
complexity, but the material is in a constant state of flux.

In describing above my observations on the migration of nuclei,
it was suggested that the nuclei move about in the mother-cell
as if they all bore electrical charges of like sign while the plasma
membrane bore charges of opposite sign. The location of elec-
trical charges on the membranes of the cell seems quite probable
from the standpoint of recent developments in physical chemistry.
According to the Gibbs-Thomson principle, there is a tendency
for substances to accumulate upon surfaces. It is practically

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 309

certain that the ions of many inorganic salts are to be found within
the cell, and these are known to have a relatively high speed of
diffusion, and hence might be thought of as accumulating upon
the membranes of the cell. If, as there is some evidence to indi-
cate, the plasma membrane is colloidal and if it may be. inferred
that the same is true of the nuclear membrane, this colloidal
condition would serve to increase very much the amount of ionic
material which might be adsorbed upon the membranes. It is
not difficult then to see how great numbers of ions might accumu-
late there, and if they are of like sign they would give to that
membrane an electric charge.

If, for example, the nuclear sap were markedly acid and the
cytoplasm be markedly alkaline, there will accumulate upon the
plasma membrane charges of one sign, while upon the nuclear
membrane there will accumulate predominately charges of the
opposite sign. It seems thus possible from a physico-chemical
standpoint that such membranes may have acquired opposite
charges. But for the purpose of this discussion, it makes no
difference how these membranes may have received their charges;
it is simply proposed to show that they, at least at certain stages,
behave as if so charged.

As noted above, the nuclei of like charge would repel each other
and hence take up a tetrahedral arrangement within the cell.
The charges upon the plasma membrane and nuclear membranes
would not necessarily be neutralized by contact of the membranes
since the ions are adsorbed.

The mutual repulsion of the nuclei and their attraction for the
plasma membrane opposed by the repulsion between different
areas of the plasma membrane will tend to transform the perfect
sphere into a tetrahedron with four equal triangular faces, each
parallel to the plane of three of the nuclei. Now the center of
each of these triangular faces will be attracted equally by each of
these three nuclei and also to some degree by the fourth. The
resultant of these four forces will tend to draw this point toward
this fourth nucleus; and the latter will exert relatively more force
of attraction upon this point than any one of the other three nuclei;
for, though it is farther away, it is working in the direction along
which the point will move. This portion of the plasma membrane
will tend to move toward the fourth nucleus, that is, toward the

310 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

center of the cell, and there will thus be formed an invagination
or projection of the plasma membrane from the center of each of
its triangular faces toward the center of the cell. Now let the
accompanying diagram represent the cell at the stage just described:

TEXT-FIGURE I. Diagram of mother-cell before division.

Let a, b, c, and d be the four nuclei, and let e be a point on the
plasma membrane equidistant from a, b, and c. The cell is shown
in its three dimensions, and these must be kept in mind during
the discussion. Two of the four nuclei, a@ and c, are on either side
of the plane of the diagram. Let xy be a plane tangential to the
plasma membrane at the point e, and let x be the point of inter-
section of the perpendicular dropped from 6 to the plane xy. By
actual measurement of the cells, ed is about 16 microns, cb is 14
microns, and xb is 7 microns. Now if there is an attraction be-
tween each of the nuclei and the point e, this point would tend to
move along the line ed. Let EB represent the force exerted by b
to draw e along the line ed. Then the force exerted by a and c
respectively would also be equal to EB; therefore the total force
exerted by the three nuclei, a, 6, and c will be 3EBB. LetniB
represent the force exerted by 6. The force exerted by a and c
respectively will also be EB. Now the angle xeb may be shown
geometrically to be one-half of a right angle. Therefore the
resultant of the forces exerted by the three nuclei, a, b, and c,
will be about 2EB. Now ed is less than 2e), and therefore, since
the force is inversely proportional to the square of the distance,

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS Suita

the actual force exerted by d would be less than HB. As e ap-
proaches d this force would be much greater, whereas the force
resulting from the attraction of a, 6, and c would diminish. The
resultant of forces in the early part of the process would be about
3EB. But ina binucleate cell the resultant of forces which would
operate to draw the plasma membrane along the equatorial plane
would be the sum of the attracting forces of only two nuclei, each
in such a relation as b toe. It thus appears that the resultant of
forces in a binucleate cell would be less than those in a tetra-
nucleate cell.

When the furrow is formed, the nucleus is more nearly enveloped
by the plasma membrane and hence the position of equilibrium,
on the basis of the electrical charges postulated above, would
be nearer the center of the lobes. And when constriction is com-
plete we should find the nucleus in the exact center of the daughter
cell. It is to be borne in mind, of course, that the furrows as they
come nearer and nearer together, being of like sign will repel each
other. Also the opposite surfaces of the same furrow as it grows
deeper and deeper will more and more repel each other. The
problem almost immediately becomes too complex for analysis
in the present condition of our knowledge as to the actual distri-
bution of the ions in the cell solutions and on its membranes. |
have merely endeavored to point out certain possibilities as to the
distribution of the forces concerned in initiating cell-division by
the process of constriction. While it is not contended that these
electrical charges are the only factors in the division of the cells,
yet it is interesting to note that both the nuclear and plasma mem-
branes behave in the initial stages of division as if so charged.

It is quite likely that the thickened mother-wall exerts no un-
evenly distributed force of compression upon the protoplast while
in the spherical form. The tetrahedral arrangement of the spores
has been shown to have originated in the migration of the nuclei
when the mother-cell was spherical in form, hence it is not neces-
sary to postulate the cell-wall as the determining factor in the
accomodation to least surfaces, which is effected by the tetra-
hedral arrangement. Furthermore, the surface tension of the
protoplast may be well thought to operate to bring about this
result. The mother-wall seems to behave as if it were a plastic,
more or less gelatinous, substance with some elasticity, so that it

312 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ©

would offer little or no resistance to changes in form of the cell
within. The mother-cell then as soon as the mutual pressure of
other cells is removed, assumes the form of least surface, doubtless
due to cell-turgor and surface tension.

It seems entirely probable that the cellulose wall of the typical
plant cell exerts much more opposition to changes in the form of
the protoplast, and has a restraining effect against an increase in
volume. But whether the typical cell-wall of plants has a high
or low degree of elasticity, we must conclude that these mother-
cells with their spherical form and loose arrangement in the pollen-
chamber are free to undergo such changes in volume and form as
their internal constitution will favor. The pollen-mother-cell
thus approaches the condition which is found in the egg cells of
many animals, and it is quite suggestive that we should here find a
mode of cell- Sinem quite like that in the latter. Whether we
shall be able to explain this division in plants on the basis of surface
tension, as Robertson and McClendon have attempted in animal
cells, is perhaps a question. But it is clear that such factors as
surface tension, osmosis, and electrostatic equilibrium are in-
volved and their relation to the process must be considered.

It may be that this close approach in the quadripartition of
pollen-mother-cells to the animal type of cell-division may throw
some light on the nature of the cell-plate. It is possible that in
all cell-divisions, animal and plant alike, there are fundamental
conditions tending to cell-plate formation, and that in the majority
of the cells of higher plants alone do we have the full complement
of factors necessary for the expression of these conditions in the
form of a visible structure. The ability of these pollen-mother-
cells to enlarge to a point of equilibrium between osmotic pressure
and surface tension may present conditions favorable for the
process of anatonose, as Errera termed it, in which soluble sub-
stances are formed in the equatorial plane. In the ordinary
tissue cells of the higher plants, the retentive cell-wall and adjacent
cells may make such enlargement impossible'so that katatonose oc-
curs and a coagulation or precipitation of a compound organic salt,
takes place in the region of the equator. ‘The relation of the spin-
dle fibers to cell-plate formation, and the relation of the former to
the nuclei, favors the idea that the cell-plate is primarily of nuclear
origin. It is not unthinkable that in all cases complex or simple

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 313

unsatisfied soluble ions may diffuse outward in all directions from

the nuclei, possibly streaming along the paths in the colloidal

protoplasm marked by the fibers. The ions from different nuclei
would meet in an equatorial plane and might, if conditions admit,
form an undissolved compound. If, however, the cell was able
to admit water and increase in volume in response to the increased
osmotic pressure, these salts might remain at a concentration
below the saturation point and hence not precipitate. May it
not be that such a condition exists in these mother-cells, which
are able to increase their volume considerably? On this in-
terpretation there would be in these mother-cells an invisible
cell-plate of soluble material, and the relation of division by
furrows to that of the ordinary type of higher plants becomes more
comprehensible.

X. LITERATURE CITED

1. Allen,C.E. (a) Ann. Bot. 19: 189-256. 1905. (0) Arch. Zellforsch.
Oo: 121-185... 1912.

2. Andrews, F. M. Beih. Bot. Centralbl. 11: 134-142. 1902.

3. Atkinson, G. F. Bot. Gaz. 28: 1-26. 1899.

4. Baranetzky, J. Bot. Zeit. 38: 241, 265, 281. 1880.

Bepeer, R. (@) Ann. Bot. 25: 199-214. xoir. (0): Ann. Bot. 26:
705-720. TOI2.

6. Berthold, J. Protoplasmamechanik. Leipzig. 1886.

7. Boveri, Th. Zool. Jahrb. 14: 630-653. Igol.

8. Byxbee, E.S. Proc. California Acad. Sci. Bot. III. 2: 63-82. 1900.

9. Calkins, G. N. Bull. Torrey Club 24: 101-115. 1897.

10. Cannon, W. A. Bull. Torrey Club 30: 133-172. 1903.

11. Davis, B. M. Bot. Gaz. 28: 89-109. 1899.

12. Denniston, R. H. Trans. Wisconsin Acad. Sci. 15: 664-708. D
1907. .

13. Dighyee, a) Aun. Bot. 24° 727-757. ror1o. (6) Ann.’ Bot. 26:
357-388. I9I12.

14. Duggar,B.M. (a) Bull. Torrey Club 26: 89-105. 1899. (0) Bot.
Gaz. 29: 81-97. 1900.

15. Ernst, A., & Schmidt, E. Ann. Jard. Bot. Buitenzorg II. 12: 1-64.
1913.

16. Farmer, J. B. (a) Ann. Bot. 8: 35-52. 1894. (6) Flora 80: 56—
67. 1895. (c) Ann. Bot. 9: 363, 364. 1895. (d) Ann. Bot. 9:
469-523. 1895.

17. Farmer, J. B., & Moore, J. E. S. Quart. Jour. Mic. Soc. 48:
489-557- 1905.

314 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

18. Farmer, J. B., & Williams, J. L. (a) Phil. Trans. Roy. Soc. London
B. 190: 623-645. 1896. (b) Ann. Bot. 10: 479-487. 1896.

19. Fischer, M. H. Science II. 42: 223-226. 1915.

20. Fraser, H.C.I. Ann. Bot. 28: 633-642. 1914.

21. Frye, T. C., & Blodgett, E.B. Bot. Gaz. 40: 49-53. 1905.

22. Gallardo, A. Interpretacién dinamica de la divisién celular. Buenos
Aires, 1902.

23. Gates, R. R. Bot. Gaz. 43: 81-115. 1907.

24. Giesenhagen, K. Zelltheilung im Pflanzenreiche. I-91. 1905.

25; Gregory, R. P. Proc. Camb: Phil. Soe:-13: 148:

26. Guignard, M. (a) Ann. Sci. Nat. VI. 14: 26-45. 1882. (6) Ann.
Ser. eMac VIEL» 6: 177-220. ‘F89755 xc): Compt: Rend: 160;
428-433. I915. |

27. Gurwitsch, A. Morphologie und Biologie der Zelle. 437 pp.
Jena. 1904.

28. Harper, R. A. (a) Jahrb. Wiss. Bot. 29: 655-685. 1896. (bd)
Jahrb. Wiss. Bot. 30: 249-284. 1896. (c) Ann. Bot. 13: 467-
525. goog. (¢d) Bot. Gaz. 30: 217-251.) 19004, (é), Trans. Ame:
Micro. Soc. 31: 65-82. 1912. (f) Am. Jour. Bot. 1: 127-144.
IQT4.

29. Hartog, M. Proc. Roy. Soc. London. B. 76: 548-567. 1905.

30. Hof, A.C. Bot. Centralbl. 76: 65—, 113—, 221-227. 1808.

31. Hofmann, R. W. Zeit. Wiss. Zool. 63: 379-432. 1898.

2. Hofmeister, W. (a) Abh. math.-phys. Cl. K. Sachs. Ges. Wiss. 2:
636. 1861. (6) Lehre von der Pflanzenzelle. Leipzig. 1867.

33. Hutchinson, A. H. Bot. Gaz. 59: 287-300. 1915.

34. Ishikawa, M. Bot. Mag. Tokyo. 25: 1-8. IogII.

35. Juel, H.O. (a) Jahrb. Wiss. Bot. 30: 205-226. 1897. (6) Jahrb.
Wiss. Bot. 35: 626-659. 1900.

36. Juranyi, L. (Ref.) Bot. Centralbl. 12: 213-216. 1882.

37. Kuwada, Y. Bot. Mag. Tokyo. 25: 163-181. I9gII.

38. Lawson, A. A. Proc. California Acad. Sci. Bot. III. 1: 168-188.
1898.

39. Levine, M. Mem. N. Y. Bot. Garden 6: 125-147. . 1916.

40. Lubimenko, W., & Maige, A. Rev. Gén. Bot. 19: 401, 433, 474, 505.
1907.

41. Maneval, W. E. Bot. Gaz. 57: 1-31. 1914.

2. Miyake, K. Jahrb. Wiss. Bot. 42: 83-120. 1905.

43. Mohl, H. von. (a) Diss. 1835, umgearbeitet in den Vermischten
Schriften. 1845. (b) Linnaea 13: 274-290. 1839. (c) Grund-
ziige der Anatomie und Physiologie der vegetabilischen Zelle.
1851.

44.

68.
69.

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 315

Mottier, D. M. (a) Jahrb. Wiss. Bot. 30: 169-204. 1897. (bd)
Ann. Bot. 14: 163-192. 1900. . (c) Jahrl. Wiss. Bot. 31: 125-
158. 1897.

. McAllister, F. Ann. Bot. 27: 681-695. 1913.
. McClendon, J. F. Jour. Phys. 27: 240-275. IgIo.
. Naegeli, K. Zur Entwickelungsgeschichte des Pollens. Ziirich,

1842.

. Nemec, B. Jahrb. Wiss. Bot. 33: 313-336. 1899.
. Nichols, M. L.: Bot. Gaz. 45: 31-37. 1908.
/ Osawa, J.. (a) Jour. Coll. Agr. Imp. Univ. Tokyo 4: 237-264.

rors. (b) Aceh. Zelltorseh. s102.450-469. | 1913.

. Overton, J. B. Jahrb. Wiss. Bot. 42: 121-153. 1906.

; Pace, I. Bot.,Gaz: 54: 306—329.. -1912.

. Pringsheim, N. Pflanzenzelle. Berlin, 1854.

. Rabl, C. Jahrb. Morph. 10: 214-330. 1885.

. Robertson, T. H. Arch. Entw. Mech. Org. 32: 308-313. I9II.

. Rosanoff, S. Jahrb. Wiss. Bot. 4: 441-450. 1865.

. Rosenbeg, O. (a). Bot. Tidssk. 28: 143-170. 1907. (0) Ber.

Deutsch. Bot. Ges. 21: I10-II9. 1903.

. Russow, E. Mem. Petersb. Acad. VII. 19: 1-205. 1872.

. Sachs, J. Lehrbuch der Botanik. 1874.

. Samuelsson, G. Sv. Bot. Tidsk. 8: 181-189. 1914.

. Schdffner, J. H. (a) Bot. Gaz. 41: 183-190. 1906. (0) Bot.

Gaz. 47: 198-211. 1909.

. Schlacht, H. Bot. Zeit. 8: 457—, 473-, 489—. 1850.

. Shibata, K., & Miyake, K. Bot. Mag. Tokyo 22: (281)—(316). 1908.
. Shoemaker, D. N. Bot. Gaz. 39: 248-266. 1905.

- Smith, R. W. Bot. Gaz. 30: 361-377. 1900.

. Stevens, W. C. Ann. Bot. 19: 465-474. 1905.

. Strasburger, E. (a) Ueber Zellbildung und Zelltheilung. Jena,

1875. (b) La formation et la division des cellules. Jena,
1876. (c) Ueber den Theilungsvorgang der Zellkerne und das
Verhaltniss der Kerntheilung zur Zelltheilung. Bonn, 1882.
(d) Ueber den Bau und das Wachstum der Zellhaute. Jena,
1882. (e) Arch. Mik. Anat. 23: 3-62. 1884. (f) Hist. Beit.
1-4-2505 sfeso. (2) Jahrb. Wiss. Bot. 31: 511-598. . 1898.
(h) Ber. Deutsch. Bot. Gesell. 19: 450-461. I9go01. (2) Jahrb.
Wiss. Bot.-37+ 477-526...1902.. (j) Flora.g97: 123-191. \: 1907.
(k) Hist. Beitr. 4: 49-158. 1892.

Swingle, W. T. Jahrb. Wiss. Bot. 30: 297-350. 1897.

Tahara, M. Bot. Mag. Tokyo 24: 23-27. I9gI0.

70. Tangl, M. Denksch. K. Akad. Wiss. Wien 45: 73-. 1882.

6 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

. Terni, T. Arch. Zellforsch. 12: 1-96. 1914.

. Thompson, D’A. W. Science II. 34: 417-428. I9II.

. Timberlake, H. G. Bot. Gaz. 30: 73-99; 154-170. 1900.

. Tischler, G. (a) Ber. Deutsch. Bot. Ges. 24: 83-96. 1906. (0)

Jahrb. Wiss. Bot. 42: 545-578. 1906. (c) Arch. Zellforsch. 1: 33-
151. 1908. (d) Arch. Zellforsch. 5: 622-670. I9I10.

. Treub, M. (a) Verh. K. Akad. Wetensch. Amsterdam 19: 1-34.

1878. (b) Ann. Jard. Bot. Buitenzorg 2: 32-53. 1885.

76. Tschistiakofi, J. Bot. Zeit. 33: 1-, 17-, 33-,8I-, 97-1329) gaa
1875.

771 atG, &. se OU. tap. Zool. 9: 143-157. I9I0.

78. Wager, H. Ann. Bot. 18: 29-55. 1904.

79. Went, F.C. Ber. Deutsch. Bot. Ges. 5: 247-258. 1887.

80. Wiegand, K. M. Bot. Gaz. 28: 328-359. 1899.

81. Wille, N. Forh. Vidensk.-Selsk. Christiania, no. 5. 1886.

82. Wimmel, T. Bot. Zeit. 8: 225-, 241-, 265-, 289-, 313. 1850.

83. Wisselingh, C. van. Beih. Bot. Centralbl. 23: 137-156. 1908.

XI. Explanation of plates 27-29

The accompanying drawings were made with a Leitz one-sixteenth objective, Apert.

1.32, and ocular, number 3, with a tube length of 15. The cells are magnified about
1000 times in figures I to 19 inclusive, which are of living cells of Nicotiana. The fixed
cells of Nicotiana, figures 20 to 37 inclusive, were drawn about 1875 times their actual
size.

. Mother-cell in presynapsis.

. Diakinesis, wall thickened.

. Equatorial plate stage of heterotypic karyokinesis.

Anaphase and telophase of homoeotypic mitosis.

Furrows which divide mother-cell just appearing.

Similar stage, showing large intercellular spaces.

. Similar stage, with content plasmolysized to show ridges on wall.

. Furrows well developed, and having invaded the center of the cell.
. Isthmus becoming quite narrow.

. Another cell in similar stage.

. Isthmus having become very narrow.

. Similar stage.

. Division complete, cell plasmolyzed to show form ot cross-wall.

. Division complete, spores changing from an elliptical to a spherical form.
. Spores become perfect spheres, mother-wall becomes thinner.

. Four spores of unequal size, within the mother-wall.

. Three spores of equal size within the mother-wall.

. Two large and one small spore within the mother-wall.

. Two spores within the mother-wall.

. Synapsis, showing wall thickened at ends of cell, and middle lamella.
. After heterotypic karyokinesis, ends of fibers attenuated.

. A little later, spindle inflated, wall thickening.

-S = SO Ot
PwWNH OUD ODNAKHLWDND H

no -+ -— = SS
ou on AY

No oN
N=

Mem. N. Y. Bot. GARDEN
ot ae

aa
T.

EAs
=< = «
06)

fo.
‘e,

UME VI, PLATE 27
ve
<4

@
806 4

Ari ee

VOLUME VI, PLATE 28

N. Y. Bor. GARDEN

Mem.

HELIOTYPE CO., BOSTON

CYTOKINESIS OF POLLEN-MOTHER-CELLS

FARR:

Meo. N. Y. Bot. GARDEN VoLuME VI, PLATE 29

HELIOTYPE CO., BOSTON

FARR: CyYTOKINESIS OF POLLEN-MOTHER-CELLS

d :
@ - ‘fs is - .f .) a b
; Pen Me er : 4

A
7
-
.
{

FARR: CYTOKINESIS OF POLLEN-MOTHER-CELLS 317
23. Anaphase of homoeotypic, spindles nearly at right angles, cytoplasm not shown.
24. Early telophase, cytoplasm granular, wall uniformly thickened.

25. A little later, cell spherical, spindles appearing, peripheral cytoplasm not shown.

26. Nuclei organized, cytoplasm fibrous, wall much thickened, surface only of upper
nucleus shown.

27.. First indication of cell-division, upper nucleus not shown in central section.

28. Sides of mother-wall becoming concave, spindles distinct.

29. Furrows deepen, nuclei draw away from the membrane.

30. Spindle fibers straighten, and draw away from the center of the cell.

31. Furrows become more abrupt.

32. Projections of the mother-wall reach the center of the cell, all three nuclei shown
in central section.

33. Tangential to two nuclei, showing the invagination of the cell-wall.

34. Unequal narrowing of isthmuses.

35. Furrows sharpen, and daughter cells begin to round up.

36. Division complete at one isthmus, before the others.

37. Spores distinct and imbedded in the thickened mother-wall, cytoplasm alveolar.

» .
:
x _—
“J —
a
£i:
Py
. . : - .
‘es
‘ : f ¥
. s - y a
7 € ciel -
re =,
be! ——
je ee ps
“a yed -
. wes
# : Se ‘ ey
a ron fs
eS . i : nan :
2 y aca
CR eee he Re Og le a i ee hae bs oo ay

PLANT ECOLOGY AND THE NEW SOIL FERTILITY

Cuas. B. LIPMAN

University of California

The writer of this brief statement begs the indulgence of his
auditors and requests consideration by them of his suggestion for
employing the methods of modern soils science in the study of
problems of plant ecology. It has been demonstrated beyond
cavil that no royal road is available which leads to the solution
of the problems of plant nutrition under field conditions and to
that of a control of all the factors necessary to proper plant growth
which are controllable. Moreover, empiricism has proved itself
woefully inadequate to cope with the problem in the face of one
of the most complex situations which confront the investigator
in any branch of scientific activity. It appears to be high time
therefore that methods be adopted in plant ecological investiga-
tions which are based on sound principles obtained from investi-
gations in the pure sciences. The methods of attack employed
by the modern soils scientist it seems to me are admirably adapted
to such study since they have resulted from an attempt to escape,
in soils science, from the empirical and haphazard, and are now
forging ahead systematically with one factor in view at a time,
in the development of a new and more justifiable view-point in
soil and plant studies.

Until now the criteria employed in the study of the so-called
plant associations have been few and their raison d’étre ofttimes a
questionable one. From the standpoint of the soil, moreover,
scarcely any criteria have been developed which might serve us
in judging of the conditions instrumental in causing the establish-
ment of flora through secular selection. To be sure, some atten-
tion has been paid to the reaction of the soil as affecting the nature
of the flora and studies have been made which bear on the part
played by the plants with nitrogen fixing powers in establishing
through encouragement or competition certain recognized plant
associations. Unfortunately, however, the question of a soil’s

319

320 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

reaction has been accorded so much weight in these considerations
that natural floras have been classified in accordance with their
dependence on or antipathy for lime. In the case of the study
of the influence of the nitrogen-fixing powers of plants, on the
other hand, and their effects in the premises, a mere beginning
has been made. Such attempts therefore as have been made to
correlate natural floras with the soil conditions upon which they
are produced, have on the whole been obstacles rather than aids
to progress.

It is well known to all of you that plant physiology has been
making great strides in its campaign against the unknown in
plant nutrition. Some of you may also be aware that the more
modern soils scientists employing the results of plant physiology
and those of physical and colloid chemistry have been able to
shed much light on certain hitherto mysterious manifestations in
plant growth and plant diseases. Their methods have consisted
in studying the effect not only of the qualitative nature, but
also of the balance between components and the total concen-
tration of the nutrient solution. Moreover, they have gained
some insight into the processes whereby colloids are enabled to
affect the foregoing factors very markedly as well as to affect the
available water supply. In addition, they have learned to study
the specific requirements of plants for forms of plant food materials
and these investigations have already yielded and will continue
to yield data of great moment in our approach to a more definite
knowledge of plant requirements and hence of the role played by
soil conditions in the establishment of floras. In illustration of
these remarks, I may call your attention to the studies of Hutchin-
son and Miller and of Schreiner and his associates on the influence
of the form of nitrogen best suited to the nutrition of certain
plants, to Skene’s work on the reaction of peat soils in relation to
characteristic floras there, and to the experiments of Stiles, Totting-
ham, Shive, McCall, Gile and others on the concentration of the
nutrient solution and its effect on plant growth.

A consideration of such studies, and I have only adverted to a
few of them here, must impress the student of plants and soils
with their momentous significance for the future of our knowledge
of plant biology both pure and applied. Particularly for the
subject immediately under consideration it would appear to the

_ LIPMAN: PLANT ECOLOGY AND SOIL FERTILITY 321

writer to be of the greatest importance in studies of any given
natural flora like the chapparal formation on the Pacific coast,
for example, that we know something regarding the following
factors in their relationships with the plants in question.

1. The proper qualitative nature of the soil solution.

. The proper balance between the components thereof.

. The proper concentration of the soil solution.

_ The proper form of nitrogen for the plants.

_ The influence of quantity and quality of organic matter.
The proper basicity or acidity for the plant.

_ The mutual influence of plants growing together on their
welfare.

Studies on these subjects now being made by the modern special-
ist in soil fertility on cultivated plants and by some plant physi-
ologists in general can therefore render great aid to the phyto-
geographer and plant ecologist in the solution of problems which
cannot fail to interest all biologists.

It is therefore hoped that many codperative experiments may be
established between the plant ecologist and the soils scientist in
all parts of this country and elsewhere. Such cooperation will
surely redound to the benefit of all the branches of study concerned
and to the investigators individually who may be involved in them.

Anup wn

“J

CHEMOTROPIC REACTIONS IN RHIZOPUS
NIGRICANS

ARTHUR H. GRAVES

Connecticut College for Women

The question of the behavior of fungal hyphae in relation to
chemotropic stimuli has for some time been a rather weak ele-
ment in the groundwork of our knowledge of the physiology of the
fungi. Miyoshi,! who was the first one to carry on any con-
siderable investigation of the subject, tested a large number of
chemical substances for their power of inducing chemotropic
reactions in fungal hyphae. Asa result of this work he declared
that many of the substances exerted a positive stimulus, causing
the hyphae to grow toward the diffusion centers, others a nega-
tive stimulus, so that the hyphae turned away, while still others
seemed to produce no effect. Without going into Miyoshi’s
work more in detail here, the main thing for us to observe is his
conclusion that chemical substances do cause reactions, expressed
in more or less marked growth curvatures.

The work was taken up again by Clark’ in 1902, and later in
1906 by Fulton.’ The most significant thing about their investi-
gations was the fact that although using his same methods, they
were utterly unable to confirm Miyoshi’s conclusions. Growth
curvatures of the hyphae were indeed observed, but apparently
not as a result of the stimulus of the substances tested. Among
his control experiments, Miyoshi had injected leaves with pure
water, sowing spores on the leaf surface. No turning of the
hyphae through the stomata resulted in this case, although the
turning had been marked when the leaf was injected with, e. g.,
cane sugar solutions. Clark injected leaves with various con-
centrations of copper, cobalt salts, etc., and found that in this

1 Miyoshi, M. Ueber Chemotropismus der Pilze. Bot. Zeit. 52: 1-28. 1894.

2 Clark, J. F. On the toxic properties of some copper compounds with special

reference to Bordeaux mixture. Bot. Gaz. 33: 26-48. 1902.
3 Fulton, H. R. Chemotropism of fungi. Bot. Gaz. 41: 81-108. 1906.

323

324 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

case the germ tubes near the stomata curved towards and grew
directly into them. But he obtained a similar result with leaves
injected with pure water only. In experiments in which he used
perforated mica plates, he found that the germ tubes near the
perforation always “grew toward the opening tf it communicated
with a layer of medium in which no spores had been placed.” A\l-
though he had no occasion to follow out this line of work experi-
mentally, he advanced the hypothesis that Rhizopus is ‘‘markedly
negatively chemotactic to some secretion of its own mycelium, and this
negative chemotropism ts much greater than any positive chemotropism
at may have for food substances or oxygen.”

Also, in Miyoshi’s control experiments, in which he used per-
forated membranes, he claimed that when the layers of medium
were of the same nature on both sides of the membrane, the spores
being sown in one of the layers, no turning towards the other
layer resulted. On the other hand, Fulton, after using essentially
similar methods, announced as follows: ‘“‘AJll of the fungi tested
show a tendency to turn from a region in which hyphae of the same
kind are growing, toward one destitute of hyphae, or in which the
hyphae are less abundant... . This may be regarded as a negative
reaction to stimuli from chemical substances which owe their origin
in some way to the growing fungus.”

Miyoshi’s conclusions have in general been accepted by recent
writers of textbooks on plant physiology. The late Professor
Barnes! described Miyoshi’s results, but also wrote significantly
as follows: “Very striking reactions to chemical compounds of
many sorts have been ascribed to the hyphae of fungi and to
pollen tubes. Chemotropism of the latter may be maintained
still as it has not been seriously impeached; but that of fungus
hyphae has been brought under suspicion by the latest researches,
and may be either established or disproved by further study.”

The present paper is a short review of work which was carried
on at the Laboratory of Plant Physiology and Pathology, Im-
perial College of Science and Technology, London, under the
direction of Professor V. H. Blackman, in the hope of deciding
between the views of Clark and Fulton on the one hand and those
of Miyoshi on the other.

1 Coulter, J. M., Barnes, C. R., & Cowles, H.C. A textbook of botany for colleges
and universities I: 473-474. 1910.

GRAVES: CHEMOTROPIC REACTIONS IN RHIZOPUS 325

Although Rhizopus nigricans Ehrenb. was the species mainly
worked with, Botrytis cinerea Pers. and Penicillium No. 24 Thom!
were also used, and there is evidence at hand that the results given
for Rhizopus are applicable to them also.

In work of this sort the methods are all-important, especially the
method of estimating the intensity of the chemotropic reaction as
expressed in the directions assumed by the hyphae. The method
finally adopted for this, as well as an account of all of the technique,
will be published later: it will suffice to say here that the method is
based on the doctrine of chances; 1. e., considering a large number
of hyphae, if all external conditions are equal, as many hyphae
should turn in one direction as another. Any deviation will
indicate a reaction to a disturbing force.

For making the preparations, the perforated mica plates were
adopted which were used by Miyoshi and also by Fulton and Clark,
with the holes, however, spaced farther apart; as preliminary
experimental work had shown that with the holes nearer together
the diffusion was fairly rapid. The perforated plates separated
two layers of medium, and various combinations of spores and
chemical substances in these two layers were tried, as will be
shown later. As to the external conditions under which the
experiments were carried on, all inequalities of moisture content
in the medium and in the surrounding atmosphere were as far as
possible eliminated, and the preparations were incubated in a
dark chamber at a constant temperature.

Experiments with the “staling substance.’’—Very early in the
work, while testing various percentages of sugar and glucose, I
obtained a complete confirmation of the results of Clark and of
Fulton in that the hyphae always turned towards the sporeless
layer, whether it contained sugar or not. The more hyphae
present, the stronger was the turning. If the spores were sown
in both layers, no turning resulted in either layer, or it was not
nearly as pronounced. According to the hypothesis of Fulton
and Clark, above stated, this phenomenon was probably due to a
negative chemotropic reaction to some substance excreted by the
mycelium of the fungus itself.

In order to prove this hypothesis, the problem was now to

1Thom, C. Cultural studies of species of Penicillium. U.S. Dept. Agr. Bur. An.
Ind. Bull. 118. 1g9t0.

326 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

obtain, if possible, this substance, which we may for convenience
call the ‘‘staling substance,’’ free from mycelium; and determine
whether, if incorporated in a sporeless layer, it would repel the
hyphae from growing into that layer.

It was found impossible to grow the fungus luxuriantly enough
in sugar solutions (probably on account of the lack of nitrogen)
to produce an adequate amount of the staling substance. But
turnip juice, pressed from autoclaved white turnips, was finally tried
with excellent results. Previously sterilized flasks containing
this, and inoculated with Rhizopus spores, produced a luxuriant
growth ina few days. After about a month, the juice was poured
off and freed of any spores and mycelium by centrifuging. The
staled juice had a sour, malt-like odor, and showed an acid reac-
tion to litmus. By adding this juice to the agar for the sporeless
layer, and using the fresh juice for the layer with spores, no turning
of the hyphae resulted. In previous experiments where fresh
instead of stale juice had been used, but with the other conditions
the same, the turning had invariably been practically 100 per cent
(cf. C of TABLE I.). Furthermore, by evaporating the staled juice
under reduced pressure at laboratory temperature to one half
volume, or double strength, the hyphae were caused actually to
turn away from the vicinity of the holes.

The theory that the hyphae excrete some substance or sub-
stances which produce a negatively chemotropic effect, is there-
fore fully proved, and the chief evidence may be summarized as
follows:

1. According to the strength of concentration of the staling
substance, the hyphae show no turning toward, or may turn away
from, a layer containing this.

2. When an approximately equal amount of mycelium occurs
in two layers, each composed of the same medium, no turning
from one layer to the other results.

3. The hyphae always show a marked turning from the medium
in which they are growing to a medium without hyphae, provided
the latter does not contain their staling substance or other nega-
tively chemotropic substances.

Experiments with fresh turnip juwice.—After the existence and
nature of the negative chemotropism was settled, it was easier
to search for a possible positive chemotropism. For, without

GRAVES: CHEMOTROPIC REACTIONS IN RHIZOPUS Gay,

going into detail, it was clear from the fact that the hyphae are
continually producing a staling substance, that the number of
spores and the length of the hyphae must be taken into account
in experimental work on positive chemotropism. In the ex-
periments with agar with fresh turnip juice added, the first
definite indication of a positive chemotropism—working, it is
true, side by side with the negative chemotropism—was obtained.
The hyphae grew much more vigorously in the turnip juice medium
than in sugar media. They did not in all cases grow faster: the
chief difference consisted in the thickness of the germ tubes, which
were twice or three times as thick as when grown in glucose or
cane sugar agar. Probably on account of this healthier develop-
ment they reacted much better to chemotropic influences than
when grown in the sugars.

Combinations of spores and medium were tried with results such
as shown in the following table. The arrangement of films and
spores in each combination—the latter denoted by a large letter—
is shown in the first column. Here the mica plate is represented
by the short line separating the two films, with their composition
and the location of spores in them as stated.

TABLE |
Nature of preparation Amount of reaction
Plain agar
A = 60-90%
Turnip-juice agar Rote
-++ spores
B | Turnip-juice agar ; 100%
| Plain agar (noticeable ten diameters
+ spores ; from hole)
Cc | Turnip-juice agar ; 100%
Turnip-juice agar (noticeable three diameters
spores | from hole)

The turning toward the holes in B and C was most remarkable,
but in A was not nearly so pronounced. The only difference
between B and C lay in the distance from the hole at which the
turning became noticeable, in the same period of time. In C, the
reaction was apparent at a distance of from three to four diameters
of the hole, counting from its margin. But in B, the turning
could be observed as far as ten diameters from the hole. In B

328 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

and C the turning in all cases was 100 per cent., while in A it
varied from 60 to 90 per cent.

In C, since the turnip juice was everywhere of practically the
same concentration, the only force exerted must be due to the
staling substances produced by the hyphae, i. e., a negative chemo-
tropic force. In B, however, where we have the most marked
turning of all, we can fairly assert that the turnip-juice agar in
the sporeless layer is the cause of the additional stimulus, and
exerts, therefore, a positive chemotropic stimulus; in other words,
in this case the positive and negative forces are working together.
This is borne out by the condition in A, where in the lower layer
the positive chemotropic force is working against the negative
chemotropic force, with the resulting decrease in the percentage
of hyphae reacting.

Since the existence of a positive chemotropic stimulus was thus
established, the next point was to determine the relative strengths
of the two stimuli. In the above experiments, the hyphae had
been allowed to grow to a considerable length, none being under
300 pw, and it was reasoned that with long hyphae the negative
chemotropic stimulus would be much greater than with short
ones. On the other hand, the positive chemotropic force should
be exerted just as strongly on short hyphae as on long ones. In
view of this, younger stages were examined, with results such as
set forth in the following table. The arrangement of data is as
in TABLE I.

a
PaBLeE II
Per cent of reaction | Per cent of ul Per cent of iS Total no. of
Nature of preparation at 63% hrs. from | action at 7% action at 8, hyphae ex-
sowing | hrs, from sow- | hrs, from ‘amined
} ing | sowing

Plain agar

A Turnip-juice agar 5 oF 28) 0 Seis 468
+ spores |
per Turnip-juice agar
3 Plain agar + spores 98 + 99 + 94 593
Turnip-juice agar |
D -++ spores — 13 — 8 = BOn 1025
nx? | Plain agar + spores + 17 + 38 + 46
Turnip-juice agar
~ -++ spores — 6.7
| ——
Turnip-juice agar 1228
-++ spores 3 a 6 Feil

1+ and — signs indicate positive and negative chemotropic reaction respectively.
2? Examined at 7 and 7% hours after sowing.

GRAVES: CHEMOTROPIC REACTIONS IN RHIZOPUS 329

The combinations in A and B correspond to those in TABLE 1, but
D and E are new.

E represents the control, for here conditions were made as
much alike as possible in both upper and lower layers. The turnip
juice being everywhere practically the same in concentration,
no positive chemotropic force is acting. If the number and
length of the hyphae were also equal in both films, the turning
on both sides should be no more pronounced in one direction than
another. But it is practically impossible to prepare films of
exactly the same spore number per unit of volume, and it is
reasonable to assume that the more mycelium in a given prepara-
tion, the more staling substance will be given off by the hyphae.
This is doubtless one of the factors which will influence the final
percentages in this case. Another factor is the personal error in
estimation. In spite of this, however, the method is accurate to
within 10 per cent, as shown by tests to be published later.

The results in A and B correspond with the same combinations
in the older preparations described above, and the same observa-
tions apply here. In A, as would be expected in the young stage
where the hyphae are very short—averaging 40m here in 634
hours—the effect of the negative chemotropic stimulus is slight.
Later, in 714 and 8 hours, when the hyphae are longer and more
staling substance has been given off, the percentage of turning
toward the spore-free layer is gradually increased; and as we
have seen in the older preparations described above, may become
ultimately about 100 per cent. In B, we have of course the
positive and negative chemotropic forces working together, which
accounts for the pronounced reaction.

A consideration of D now bears out our interpretation of A
and B. For since both films here contain spores, the amount of
staling substance is more or less equalized throughout the prepara-
tion, and the force of the negative chemotropic stimulus is there-
fore practically eliminated. Any reaction which occurs should
be due to a positive chemotropism, and as the tables show, there
is considerable turning from the plain agar to the turnip juice
agar. This last experiment is the one which gives the final
clinching evidence for positive chemotropism.

On the basis of these results we can get some approximate idea of
the relative intensity of the positive and negative chemotropic

330 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

stimuli. Our knowledge of the relation between individual varia-
tion in sensitiveness of the germ tubes and the intensity of the
acting stimulus is of course very vague. However, it seems safe to
assume that in general a larger percentage of turning means a
stronger stimulus.

If, then, we denote by n the strength of the stimulus causing
negative chemotropism and by /p that causing positive chemo-
tropism, we have in A of the above table, using the per cent of
reaction in the oldest preparations, n — p = 43; whereas in B we
have n+ p= 94, taking the oldest preparations here also.
Since the hyphae in these two corresponding cases were approxi-
mately equal in length, and the number of spores in the films
was about the same, a comparison is legitimate. By eliminating
the p’s we have then, 2” = 137, or m = 68.5: p will then be 25.5.
In other words, under the special conditions of this experiment,
the positive chemotropic stimulus exerted by the turnip juice is a
little more than one third as strong as the negative chemotropic
stimulus exerted by the staling substances of the hyphae them-
selves.

Similar experiments were carried on with cane sugar and glucose.
Briefly, the results of these showed a slight positive reaction to
the sugar or glucose, but so small as to be hardly above the per-
centage of error. The invariable uniformity with which it ap-
peared, however, is good evidence for the validity of the result.
A full account of these experiments, as well as other points, will be
left for later publication.

SUMMARY

1. Conclusive evidence has been obtained to substantiate the
hypothesis put forward by Fulton and by Clark that many fungi
exhibit a negative chemotropism toward their own metabolic
products (staling substances).

2. Positive chemotropism towards such substances as turnip
juice, cane sugar and glucose, also exists, but under ordinary
conditions of growth, the effect is very much less than that of the
negative chemotropism mentioned above.

3. The substances present in turnip juice exert a much stronger
positive chemotropic effect than, e. g., 10 per cent cane sugar,
which suggests that plant juices in general may evoke a fairly
high positive chemotropic response.

GRAVES: CHEMOTROPIC REACTIONS IN RHIZOPUS 331

4. It is probable that the distribution of a parasitic fungus in
its host is due not so much to positive chemotropic stimuli as to
the dominant negative chemotropism towards its own staling
products.

In conclusion, I would like to express my great indebtedness to
Professor V. H. Blackman, of the Imperial College of Science and
Technology, London, who made this work possible by his invalu-
able assistance and unstinted advice.

SELF- AND CROSS-POLLINATIONS IN CICHORIUM
INTYBUS WITH REFERENCE TO STERILITY

As BuiStourT
New York Botanical Garden

(WITH PLATE 30)

TABLE OF CONTENTS

ENTRODUCLIONS cer nersccperot nce Ore ot ebaPet telcos eee oe ane Cris erasrahel Sacer mea: d Sicevehate “Wa anche 334
DISCUSSION OF LITERATURE BEARING ON PHYSIOLOGICAL INCOMPATIBILITY....... 339
MIRTAONS.OF. STU NIN “CHICORN 5 552 a:0 «ci ceennaye chs Gare hole nue bisa it adaeaie torn ca 361
RESULTS: OF TBE EXPERIMENTAL “STUDIBS. od, .oliet s hue ig ces hoc od oi fee cio aetna s.6 364
Phenomena of self-compatibility and self-incompatibility................... 364
Self-sterility and self-fertility among plants of the F; generation......... 368
Self-sterility and self-fertility in F: progenies derived from seed of self-
WEEE Eso EVI GS i wepner sy tees a! ove. taht deem eR NREETS Chay Maes ke re ele atepee a a7
Self-fertility and self-sterility among plants of the F3 generation, etc..... 374.
Summary ofthe. yy. Fo-and Fs:generationsite ss ssh. tiv. dike es 378
Self-sterility and self-fertility in the variety “improved red-leaved
KL CEs TIGR IO er Ea eee Om tree eS, Ai Ee meee gy Sea gee te 382
Self-sterility in hybrids between a wild white-flowered plant and a plant
of the “improved stripedzleaf’” variety lac claw os tocn e's lft che ae 383
Phenomena of physiological inter-incompatibility and compatibility.......... 384
Results of crosses involving A and various of its progeny............... 384
Results of crosses between (A XC) plants and the parents.............. 387
Results of crossing (A X £3) plants and the parents.................... 389
Results of cross-pollination involving (A X £22) hybrids................ 301
Results of cross-pollination involving the variety ‘‘improved red-leaved
A eR AIO ts RD ERO he CIR PE epoca o © bop Rey Oe ame Shay ce Cae 393
General\sumunary of all cross-pollinations. 1. elas soot ee cee ee ss 395
GENERAL O ‘POTENTIALAFERTILITY IN GHICORY):! 10. Hdetthl ond 6 bole de ea ee oe 396
OBSERVATIONS ON EFFICIENCY. OF OPEN POLLINATIONS.........2.20eceeeeeecees 397
OMHERGIN VE SII GAMIONS pera Wea sy siecnrcs oc alah oy srs, a5 a eecenavere a at atara eae Py eeatne a sia caters 401
DD ESCUSSION ase cete ret taes tear omy RENT e oa Renan Aetrex ntach Meera cunic o tee erie Sees Sie 402
(Generales oe ihe eel ye ete ee ee RR eA Cee RES crs te cea 402
Special phases of the phenomena of sterility and fertility................... 408
The relation of cross-incompatibility to self-incompatibility............. 408
The sporadic and fluctuating nature of sterility resulting from physi-
Gloricalanconipatibiliiy--. wert ck Cok se Ree wicca sje Ste os es cues 409
The relation of incompatibilities giving sterility to cell organization...... 412

Relation of vegetative vigor and fertility to inbreeding and cross-breeding 416
Relation of sterility from physiological incompatibility to vegetative
Witor dan plod tetiOn Ol SCk OFSATIS.). 2.220500 cadence ssw obs s be nae es 422

Joo

334 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN-

The contrast between sterility from physiological incompatibility and

Sterility TrOM MO DOLGNCE.. a5 Fok cs ee ee es oo dp ke ee 423
Significance of serum incompatibilities, etc.............+..-eee see eeees 428

The phenomena of:pollen-tube growth. ........ «\. ...'s0 2% wispetersnte ernienenel tie 436

. Types of sterility in dimorphic and trimorphic plants.................. 440

AC ONGETISHONG parted te ae eee ier alae) areas 018 iec.ie <0 sone «alin pine 447
WOOREROGR APY (eo Fte Cr eee Car ki ees ook eo oe on od ate ee Sh ar 450

INTRODUCTION

The whole subject of sterility in plants and animals has been
sometimes more or less obscured by a loose and fluctuating use of
terms. A mass of data has, however, accumulated which makes
possible now a more careful grouping of the facts and a more
exact use of terms. The subject may be further obscured in
reference to plants by the uncertainty and confusion which has
to some extent existed as to the terminology of sexual reproduction.
Here there is no dispute as to the facts either of anatomy, morphol-
ogy, orphysiology; thedispute has been wholly as to the applicability
of the terms male and female, as used by zodlogists, to certain plant
structures that in their morphology are sporophytic. On this point
it will suffice to say that I shall consider pistils and stamens as male
and female reproductive organs during any stage of their develop-
ment, whether containing in the strict sense spores, gametophytes,
or gametes. Whennecessary to distinguish between them and their
product they will be spoken of as male and female sporophylls;
the embryo sac and pollen tubes (male and female gametophytes
with no morphological counterpart in animals) will be so desig-
nated, and egg cells and sperm cells will be spoken of as male
and female germ cells or gametes. The male and female gameto-
phytes are, of course, morphologically and physiologically differ-
entiated and constitute a new and a haploid generation. Their
action in fertility and sterility in higher plants is, however, closely
conditioned by the anatomy and the cell organization of the
sporophyte which produces them.

From our present knowledge of the facts and causes of sexual
sterility in plants, we may distinguish three main classes:

I. Sterility from impotence, in which, as I shall use the term,
normal sporophylls (with spores), gametophytes, or germ cells are
not formed. This it seems to me is a proper limitation of the
term which is, of course, frequently used more generally to refer

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 335
to various sorts of sterility, especially as it appears in animals.
Here belong such cases as:

(a) Complete impotence involving either the absence of all
floral and sex organs as in Pelargonium Madame Salleron or the
lack of sporophylls only as in certain double-flowered plants like
Matthiola:

(6) Partial or complete impotence with reference to one or the
other type of sporophyll as seen in such cases as impotence of
pistils only in double-flowered varieties of Petunia; in the impo-
tence of stamens as in Oenothera lata; in the marked impotence of
both sporophylls (failure to develop normal spores), as in the well-
known cases of contabescence of anthers and impotence of pistils
with abnormal development of spores, as exhibited by many
hybrids and by such plants as Oenothera Lamarckiana whose
hybrid origin is at least more remote; in the marked impotence of
parthenocarpic varieties, as in Citrus species; in the impotence of
the male sex organs as in the grape; or that of the female sex
organs, as in red clover (arrested sexual differentiation) at certain
stages.

While the causes are no doubt physiological, impotence ex-
presses itself as a failure in the development of the reproductive
organs or of the germ cells themselves, rather than as a failure in
the proper functioning in fertilization of such organs or germ cells.
They are all essentially cases of degeneration in the sporophyte,
including the production of its spores, excepting the cases of
degeneration of a maturing gametophyte itself, such as Dorsey
(714) has described in Vitis.

Impotency of certain types may be either temporary or perma-
nent, both in animals and in plants, and may exhibit variations and
fluctuations especially in response to such factors as disease and
cultural conditions.

II. Sterility from incompatibility—This class includes plants
which produce apparently normal reproductive organs and germ
cells, but which are nevertheless sterile through either a structural
or a functional incompatibility. The old question whether there
can be a functional failure without a structural cause I| shall not
discuss here.

The term incompatibility has been, of course, used to charac-
terize a wide range of causes of failure in reproduction, but it can

336 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

well be limited in its application to those causes existing in the
plants themselves which prevent fertilization in and between
plants with normal reproductive organs and gametes.

In such cases we may distinguish two quite distinct types of
incompatibility:

1. Anatomical incompatibility due to more or less marked
structural differences as:

(a) Obvious specific differences in structure, such as the com-

parative length of styles in two such species as Mirabilis
Jalapa and M. longiflora.

(b) Structural differences within a species, such as dimorphism
or trimorphism as seen in Linum and Lythrum (which
may be correlated with true physiological incompati-
bility).

The investigations reported in this paper do not concern this
class of incompatibilities, and a further discussion or classification
of the almost innumerable floral modifications involved will not
be attempted here.

2. Physiological incompatibility —When complete potency exists
and morphological compatibility is perfect or morphological incom-
patibilities and hercogamy are eliminated by proper pollination,
sterility may still be present as a result of physiological conditions
which make impossible the union of male and female gametes.

In the flowering plants this incompatibility may make itself
manifest in the growth of the pollen-tube through the tissues of
the stigma and style, or in the more intricate processes of fusion
of the gametes. So far as known, such physiological incompati-
bility, at least in the flowering plants, may be due to conditions
in either the sporophyte or gametophyte. In lower forms of
plant life and especially in those forms with well-marked alterna-_
tion of generations with an autonomous existence of a monoecious
gametophyte or of male and female gametophytes, such incom-
patibilities would be more strictly gametophytic. Even in the
flowering plants, however, this sort of incompatibility is, it would
seem, most intimately concerned with the fundamental processes
involved in fertilization, and presents problems whose solution
will unquestionably throw much light on the nature of sexual
fusions in general.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 337

The term physiological incompatibility may well be used to
refer specifically to such cases of sterility in plants as Jost and
Correns have assumed are due to individual stuffs or to line
stuffs in which the stigma secretions are said to inhibit rather
than to stimulate the growth of certain pollen tubes, or to cases
where egg cells and sperms do not usually unite in self-fertilization,
as reported in the hermaphrodite animal Ciona intestinalis (Castle
?96, Morgan ’04, ’10, 713).

While sterility due to physiological incompatibility is most
clearly in evidence when there is no anatomical incompatibility of
sex organs, it no doubt also exists in connection with anatomical
differences in numerous cases of interspecific sterility.

III. Embryo abortion.—Sterility due to degeneration and death
of embryos during various stages of their development and quite
subsequent to an apparently normal fusion of germ cells is com-
mon, as illustrated in varieties of the apple (Kraus ’15), in certain
hybrids of tobacco (Goodspeed 715), and in various Oenotheras
(Davis ’15a, 7155). Goodspeed (’15) has used the term ‘‘ pheno-
spermy’”’ in describing empty seeds produced “either with or
without pollination.’’ While the term is etymologically correct
in its reference to the seed as a sperm, the term may be misleading
to zodlogists. Also there may well be many cases of abortion
that do not even lead to the production of seed-like structures.
It seems best to the writer to use the expression ‘“‘embryo abor-
tion’’ for all cases of degeneration during the growth of the
embryo. Except in cases of the development of embryos by
apomixis all such cases would imply fertilization.

No doubt all such cases of embryo abortion are fundamentally
due to physiological causes and that many such involve quite
local intercellular physiological conditions, especially in the cases
of seed sterility that accompany the development of large fleshy
* fruits in which, as Kraus (15) has pointed out, there are “‘ varying
degrees of interdependence of seed and flesh formation,’’ and that
from the standpoint of fruit-growing a distinction should be made
between self-fertility (seed production) and self-fruitfulness (fruit
production). Aside from the relations of seed and flesh formation
there is abundance of evidence that sterility and unfruitfulness
may both result in many fruit crops (Waite ’95, for pears; Lewis
and Vincent ’09, for apples; Backhouse ’11, for plums; Gardner

338 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

713, for cherries; and others) from pure physiological incom-
patibility. Some cases of seed abortion may involve general
constitutional weakness on the part of the mother plant or animal.
Still other cases of seed abortion may involve an incompatibility,
intracellular in action, between chemical or structural elements of
the two sex cells which fuse to give the double mechanism of the
cells of the new sporophyte as especially noted by de Vries (710,
p. 258). The whole phenomenon of embryo abortion in its rela-
tion to the other types of sterility as noted above needs thorough
investigation, especially in respect to the extent and degree of
cytoplasmic incompatibilities that may exist between the egg and
sperm immediately after fertilization.

It should be recognized that the total sterility observed in a
species may involve several or even all the types of sterility as
outlined above. This is the case, for example, in red clover
(Trifolium pratense). In this species (Martin, ’13; Westgate and
Coe, ’15), there is often impotence especially in the first crop in
that the female reproductive organs often remain vegetative;
there is anatomical self-incompatibility seen in the adaptations for
cross pollination, and there is physiological self-incompatibility in
the very marked self-sterility that is known to exist; there is embryo
abortion not only of the usual fluctuating accidental type, but in
the regular abortion of one of the two ovules of each ovary both
of which are said to be fertilized. In the Oenotheras, Davis
(715a and db) has pointed out that ‘‘pollen sterility’”’ or ‘pollen
abortion” is very marked and that ‘‘the total amount of sterility
both gametic and zygotic is simply amazing”’ (’15d, p. 13). He
also suggests that ‘‘some degree of pollen and ovule sterility must
be expected to result”’ if there is also selective fertilization. Here
the phenomena of impotence of various grades and of embryo
abortion and degeneration are clearly present and it is suggested
that physiological incompatibility giving selective fertilization is
also in operation.

It is, however, sufficiently clear that typical cases of the various
classes here noted may exist more or less independently and that
they are quite distinct at least in the direct expression of the
contributing causes.

The investigations here reported are concerned with a sterility
which involves physiological incompatibility, and I shall discuss
dspecially the literature relating to this class.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 339

DISCUSSION OF THE LITERATURE BEARING. ON
PHYSIOLOGIGAL, INCOMPATIBILITY

All the more recent conceptions of the nature of sterility in-
volving physiological incompatibility in non-dimorphic species
are but modifications of the general view of Darwin that its
causes are to be sought in conditions of differentiation in the consti-
tution of the sexual elements. Some of Darwin’s most extensive
experimental work was done on the problem of the relative fertility
resulting from selfing and crossing as bearing on the origin of
variations and their perpetuation and accumulation in evolution.
His publications reveal a wide knowledge of the facts of fertility
and sterility, which with his discussions have a direct bearing on
such important points as, (@) occurrence of self-sterility, (6) nature
and causes of self-sterility due to self-incompatibility, (c) relation
of fertility to vigor of plants and to genetic relationship (whether
inbred or cross-bred), (d) the nature of differentiation involved in
sexual reproduction as seen in sterility and fertility.

(a) Darwin’s conceptions of self-sterility (due to physiological
incompatibility) were based on a comprehensive knowledge of the
occurrence of such phenomena. As early as 1868 he reports in
over thirty species the occurrence of “‘self-impotent”’ plants which
according to the literature and from his own observations could
not be fertilized with pollen from the same plant. He says re-
garding them: ‘‘ They are sometimes so utterly self-impotent that,
though they can readily be fertilized by the pollen of a distinct
species or even distinct genus, yet, wonderful as the fact is, they
never produce a single seed by their own pollen” (’68, 2: 164).

Darwin (’77) later discusses under the term “‘self-sterile’”’ plants
the cases of physiological self-incompatibility which he has previ-
ously (’68) designated as ‘‘self-impotent,’’ adds several species to
the list of such plants, and from his own data on Eschscholtzia cali-
fornica, Abutilon Darwinit, Senecio cruentus, Reseda odorata, and
Reseda lutea shows that self-sterility is present not as a fixed and
uniform behavior, but that it is fluctuating in its expression among
different species and also fluctuating among individuals of the
same species. Darwin obtained seed from a strain of Eschscholtzia
californica which Miller (Hildebrand ’68; Miiller’ 69; Darwin
68) had found to be completely self-sterile in Brazil for six genera-

340 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

tions. Two plants grown from such seed were feebly or semi-self-
fertile; the next year plants (number not given) raised from this self-
fertilized seed were likewise feebly self-fertile. The experiments
are not extensive nor are pedigrees indicated, yet it is clear that
some plants were fully self-sterile and others self-fertile to some
degree, giving different results in Brazil, England, and Germany,
which Darwin concludes is evidence of an influence of climate
acting on the sexual constitution (’77, p. 333).

With Abutilon Darwinii there was a feeble self-fertility in at
least some of the plants grown in England from the cross-fertilized
seed of plants which Miller found to be self-sterile in Brazil.

Three plants belonging to two varieties of Senecio cruentus were
completely self-sterile, but fully cross-fertile.

Darwin describes his experiments with Reseda odorata in con-
siderable detail. Seven plants grown in 1868 were fully self-
sterile in all controlled pollinations which were made, although
three of them produced seed by spontaneous pollination which, as
Darwin points out, may have been accidental cross-pollination.
Sixteen combinations of cross-pollination involving five of these
plants were, it appears, fertile. The next year, however, three
plants raised from a new supply of seed were strongly self-fertile
and one other plant was feebly self-fertile. In 1870 six more
plants were grown; two were almost completely self-sterile and
four were strongly self-fertile. In 1871, of five plants grown from
seed of the self-fertile plants of 1870, three appeared to be feebly
self-fertile. No evidence of cross-sterility was found in any of
these plants.

In Reseda lutea, Darwin observed self-sterile plants and isolated
two for study, one of which was ‘‘ quite self-fertile,’’ while the other
was ‘‘partially self-sterile.”’ |

(b) Regarding the nature and causes of self-sterility due to
physiological incompatibility, Darwin points out that this sort of
self-sterility is widely distributed, that it differs much in degree in
different plants, and that among individuals of the same parentage
some may be self-sterile while others are self-fertile, quite as re-
vealed by the pedigreed cultures of Cichorium which I shall report
later and which, no doubt, would likewise appear in Cardamine and
in Nicotiana hybrids were attention especially given to this point.
The phenomenon appeared, as he observed it, in plants of cross-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 341

bred origin. Darwin concluded that the sporadic character of
the phenomenon is an evidence of an incidental and abnormal
condition which he says ‘‘we may attribute to some change in the
conditions of life acting on the plants themselves or in their
parents.”

Darwin developed no formal hypothesis of sterility (physiologi-
cal incompatibility) like that of Jost or of Correns, but contented
himself with such vague statements as: ‘‘in most cases it is deter-
mined by the conditions to which the plants have been sub-
jected”’ (°77, p. 343). He emphasizes the variations in the self-
fertility of Eschscholtzia in different climates, but just how climatic
influences operate he does not attempt to say. Of the causes in
Reseda odorata, in which plants of the same parentage grown in
the same culture were self-sterile or self-fertile, he states ‘‘we are
forced in our ignorance to speak of the cause as due to spon-
taneous variability; but we should remember that the progenitors
of these plants, either on the male or the female side, may have
been exposed to somewhat different conditions” (’77, p. 344).
His main interest in the whole subject was undoubtedly from the
standpoint of the search for the causes of variations which may
become the material for natural selection in producing evolutionary
changes, but it is to be specifically noted that he considers that
the view that self-sterility (physiological self-incompatibility) ‘‘is
a quality which has been gradually acquired for the special
purposes of preventing fertilization must, I believe, be rejected”’
(?77, p. 345), and that ‘‘we must look at it as an incidental result
dependent on the conditions to which the plants have been sub-
jected” (77, pi 346).

(c) From the above it is clear that Darwin distinguished the
phenomena of self-sterility from the decreased sterility which he
conceived to result from close genetic relationship. Darwin (’77)
presents data from extensive experiments with cross- and self-
fertilization of plants which he considers proof that the degree of
self-fertility in species regularly self-fertile is less than that of
cross-fertility, and that close inbreeding decreases the fertility.
This effect he considers is especially evident in the ‘innate fer-
tility’’ (general or potential power to produce seed judged by the
fertility of a plant when exposed to open pollination by insects),
which he finds is, as a rule, decidedly greater in plants raised from

342 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

cross-fertilization or, in the case of dimorphic and trimorphic
plants, from legitimate pollination (pollination usually involving
pistils and stamens of the same length). The causes operating
in such cases are considered to be different from those causing
self-sterility as seen in plants like Eschscholtzia, for Darwin states
that self-sterility (sterility due to physiological self-incompati-
bility) ‘‘must be different, at least to a certain extent, from that
which determined the difference in height, vigor, and fertility of
the seedlings raised from self-fertilized and crossed seeds; for
we have already seen that the two classes of cases do not by any
means run parallel’ but that ‘‘this want of parallelism would be
intelligible if it could be shown that self-sterility depended solely
on the incapacity of the pollen tubes to penetrate the stigma of
the same flower deeply enough to reach the ovules” (’77, p. 342).

Darwin fully realized that the effects of inbreeding, as judged
by vegetative vigor and fertility, exhibit wide fluctuation, and that
his results show that decreased fertility does not always result
from continued self-fertilization or inbreeding in the cases of his
highly self-fertile strains of Ipomoea and Mimulus (?77) and in
the appearance of equal-styled and highly self-fertile varieties
of Primula veris and P. sinensis, so that, as he admits, it is
‘difficult to avoid the suspicion that self-fertilization is in some
respects advantageous” (’77, p. 352). Burck (’08) very ex-
haustively reviews Darwin’s results and raises the question
whether inbreeding ever decreases fertility and concludes that the
data show (a) that the greater fertility which appeared in crosses
involved impure varieties whose fertility has been already de-
creased by hybridization; (b) that continued self-fertilization does
not lead to decreased fertility and (c) that pure (homozygous)
plants show no advantage when crossed either in vegetative vigor
or fertility.

(d) Darwin’s conception of the nature of the differentiation
involved in sexual reproduction, in relation especially to sterility
and fertility, emphasized and clearly delimited the current theory
of sex, that it is differences between the sexes and sex elements
that make sexual reproduction possible and fruitful. Thus he
was of the opinion that ‘‘some degree of differentiation in the
sexual system is necessary for the full fertility of the parent plants
and for the full vigor of their offspring” (’77, p. 344, 345). ‘“‘ Fer-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 343

tilization of one of the higher plants depends, in the first place,
on the mutual action of the pollen-grains and the stigmatic
secretion or tissues, and afterwards on the mutual action of the
contents of the pollen-grains and ovules. Both actions, judging
from the increased fertility of the parent plants and from the
increased powers of growth in the offspring, are favored by some
degree of differentiation in the elements that unite so as to form a
new being” (’?77, p. 456). As to the conditions operating in self-
sterility, Darwin states that “‘their sexual elements and organs
are so acted on as to be rendered too uniform for such inter-
action, like those of a self-fertilized plant long cultivated under
the same conditions”’ (?77, p. 345). Darwin here considers that
it is lack of differentiation that leads to self-sterility.

Darwin, however, expressed no opinion of the exact nature of
this assumed differentiation, such, for example, as Sachs’ con-
ception of formative stuffs, Weismann’s theory of idioplasmic
differentiation due to assumed qualitative cell divisions, or de
Vries’ theory of intracellular pangenesis. While the determina-
tion of the nature of differentiation is essential to the knowledge
of sex phenomena, we are not at the present time able to give a
precise and exact account of the basal facts involved.

It is clear, however, that Darwin does not mean merely visible
differences such as shape, size, and color of sexual and other organs,
and that in speaking specifically of constitutional differentiation
he is mainly concerned with egg and sperm cells. He notes, how-
ever, that an attempt to compare sex relations with chemical
affinity or attraction is in harmony only with certain phases of
fertilization. The difficulty of relating pure chemical affinities
to the phenomena of so-called sex affinity is well illustrated by
Darwin’s discussion. This has become more apparent as the cyto-
logical facts are revealed, so that it is now very evident that the
chemist knows of no purely chemical relations comparable to the
cellular reactions of fertilization.

Darwin quite fully subscribed to the doctrine of functional inde-
pendence of the elements or units of the body as a general doctrine
of differentiation of organs, and of the modification of such organs
by environmental conditions. This was in fact the basis of his
doctrine of pangenesis. That this sort of differentiation is different
in degree at least from that of the sexual elements was apparently
a view held by Darwin.

344 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

’

The general term ‘‘differentiation’’ is used rather indiscrimi-
nately by Darwin, as it is quite generally, to apply to (a) different
parts of the same individual, (6) to individuals as a unit, (c¢) to
groups of individuals constituting a strain, a species, or a larger
group. The nature, interrelations and fluctuations of these
different kinds of differentiation involve, we may note, some of
the most interesting of the unsolved biological problems of today.

It is clear, as will be noted more fully later, that the differ-
entiation is of different kinds and of different degrees, and that it
fluctuates in its expression through fertility both in self- and cross-
fertilization. It would appear that in the lesser fertility of inbred
stock compared with that of cross-bred stock, which did appear in
some instances, Darwin saw a lack of constitutional differentiation
due to the more intimate relationship of parts concerned. It is
clearly evident, however, that he did not place the development
of self-sterility (physiological incompatibility) on any such basis.
He attempts thus to distinguish complete sterility (from physi-
ological incompatibility) from that which he thought is associated
with decreased vegetative vigor due to inbreeding, and to ascribe
only the latter to lack of differentiation from close relationship.

Darwin was not fully aware that, aside from ‘‘illegitimate
pollination,’”’ cross-sterility between plants of the same species
and of seed origin can exist quite as decidedly as does self-sterility.
He had quite clearly shown that intercrossing (inbreeding within
a variety), especially if the plants had been grown for some time
under similar conditions, may not give increased fertility and vigor,
and thus be quite similar to the assumed results of self-fertilization.
While in general Darwin assigned the causes of sterility to lack
of constitutional differentiation in sex, he did not relate the pecu-
liar condition of self-incompatibility to the decreased fertility
assumed to arise from close relationship, but to a sporadic response
to influences of environment. Furthermore, he failed to see any
relation between the self-sterility in non-dimorphic species as
Eschscholtzia californica and that in dimorphic forms, a point
that will be discussed later.

Attempts were made early in the study of self-sterility (self-
incompatibility) to determine the causes and to analyze the con-
stitutional.conditions through a comparative study of the growth

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 345

of pollen tubes in self- and cross-fertilization. This is an attempt
to discriminate degrees or grades of differentiation through the
immediate requirements and interactions between the sex organs
of a single plant and of different plants. Such considerations, of
‘course, involve the extensive studies that have been made upon
the physiology of pollen tubes in the attempt to determine their
irritability and nutritive requirements and to what extent their
development is determined by direct stimulation of the egg.

Jost (707) was the first to summarize such evidence in formu-
lating a theory of self-sterility. He points out from the results
that he and others have obtained in experimental studies of pollen
germination and pollen-tube growth, that. the different species
exhibit a wide variation with more or less marked specific physio-
logical differentiation, which we may note is quite in harmony
with the more recent studies. The stimulating influence of sugars,
or proteids to pollen-tube growth, and the fact that a regulation
giving a very limited supply of water is all that is necessary for the
germination and early growth of pollen tubes is an evidence that
the growth of pollen tubes in the pistil, as in artificial cultures, is
quite independent to a certain degree of the direct influence of
the eggs.

Within the species, however, self-sterility may arise from quite
individual conditions irrespective of any specific physiological
differentiation. In such cases Jost points out: (a) the pollen may
not germinate, (0) the growth of tubes fora plant may be poor in its
own conducting tissues, (c) the tubes may not respond to chemo-
tropic stimuli in tissues of its own pistil, (d) the two sex cells may
not be able to unite, (e) the product of their union may make very
poor development, or that several of these conditions may com-
bine to give sterility. All of these classes except the last I have
included under the class ‘‘ physiological self-incompatibility;" any
failure in development after fertilization I have classed as ‘“‘em-
bryo abortion” for reasons already stated.

These limitations of fertilization operating so decidedly in the
‘ndividual are made the basis of the application by Jost of the old
doctrine of ‘individual stuffs’ which is, perhaps, the first formal
hypothesis which has been advanced to account for the phenomena
of physiological self-incompatibility. The theory is in brief that:

(a) Different plants even of the same species and strain are
characterized by qualitatively different chemical substances;

346 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

(b) That the pistils and pollen tubes of any one plant possess
the same “‘individual stuff’’; and

(c) That the best growth of pollen tubes is made when they
penetrate into stigmas having another kind of individual stuff.

In respect to the ‘‘individual stuff’’ there is, it is assumed, a
differentiation between individuals quite analogous to that which
the chemical theory of species assigns to different groups of
organisms. In the single individual, however, parts so anato-
mically differentiated as sex organs are assumed to possess the
same individual stuff. Thus the distribution of the “stuff’’ is
entirely independent of any distribution of formative stuffs in
organogenesis as Sachs conceived it, or of segregations of germ
plasm units in development (in Weismann’s sense), in the reduc-
tion process of sporogenesis, or of the degree of organ specificity
that may exist. In spite of all known anatomical and physi-
ological differentiation of the organs concerned, there is, it is
assumed, a lack of differentiation in respect to the distribution of
the particular individual stuff.

Jost’s general theory minimizes the significance of fluctuating
variation in self-sterility, although he was fully aware that such
variations appear. In 1905, ninety-three autogamous pollina-
tions with Corydalis cava gave six capsules, an evidence that all
plants of this species are not absolutely self-sterile. That the
operation of any assumed individual stuffs is fluctuating is also
apparent from Jost’s careful studies of rye (Secale cereale). Ulrich,
especially, had already shown three varieties:to be feebly self-
fertile, and that varietal and individual differences exist, so that
Jost remarks ‘‘Wir sahen schon bei Corydalis, dass diese Pflanze
wahrscheinlich nicht absolut selbststeril ist. Es ist wohl moglich,
dass es absolut selbststerile Pflanzen tuberhaupt nicht gibt”’ (07, p.
89). Jost’s own studies on Secale were with a race known as Secale
montanum, in which from many isolated heads he obtained only
three seeds, one of which contained an embryo. The results of
careful studies showed that in this variety pollen tubes from
xenogamous (pollen from another plant) pollination penetrated
to the micropyle in seven to nine hours, while tubes from auto-
gamous pollination after twenty-four hours had only reached the
base of the pistil. From certain of the experiments it appears that
tubes from geitonogamous (pollen from another flower of the

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 347

same plant) pollinations grew much more rapidly and there is
some evidence especially by Ulrich (’02) that in rye such pollina-
tions may be slightly more fertile than autogamous pollinations.
Such results suggest that the assumed individual stuffs are differ-
ent in different parts of the plant, and Jost even considers that
when self-fertilization occurs in varying degrees the cause is to be
sought in variations in the qualitative nature of the pollen. Fur-
ther evidences of such variation are seen in the experiments with
two plants of Hemerocallis flava which Jost found to be self-fertile
to some degree. This result he does not consider as proof that
Focke (?93) was wrong in reporting this species as self-sterile,
but that different races and even different individuals may exhibit
marked differences in the degree of self-fertility.

Jost’s facts are in accord with those of Darwin both in respect to
the fluctuating behavior of self-sterility and to the poor develop-
ment of pollen tubes, which is the rule in such cases. Darwin
considers that highest fertility in general is due to differentiation
in the sexual elements and that both the growth of the pollen
tubes and the mutual action of germ cells are improved by in-
creasing these differences, at least up to a certain degree. Jost’s
view is based on the same underlying conception of sex. He
makes Darwin’s assumptions of ‘‘differentiation’’ concrete by
assuming that the differentiation is one of chemical substances,
his individual stuffs. Each plant has its own individual stuffs
and hence when both reproductive organs and elements are
derived from a single plant they have the same individual chemi-
cal substance, and hence lack the differentiation necessary for
proper functioning.

For the explanation of cases of feeble self-fertility, and Jost
expresses doubt that any hermaphrodite plant is fully self-sterile,
Jost assumes that individual variations may exist among the
pollen grains, giving qualitative differences quite equal to that of
the individual stuffs in different plants. Jost presents some
evidence that geitonogamy is more effective than autogamy,
but does not develop the idea that the variation in self-fertility
may have any relation to the actual physical relationship of the
organs concerned with respect to relative location on a plant.

With reference to the production of differentiating chemical
substances both of specific and individual sorts, Jost states: ‘Man

348 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

hat aber wohl allgemein geglaubt, diese Differenzen seien im
Protoplasma, spezieller im Idioplasma, noch spezieller im Idio-
plasma des Kernes zu suchen. Demgegentber haben nun die
vorliegenden Untersuchungen mit Notwendigkeit zu der Annahme
gefuhrt, dass losliche und diffusible Stoffe Trager der individuellen
Differenzen sein konnen”’ (’07, p. 112). Jost further suggests
the relation of these soluble substances to such specific sub-
stances as exist in the blood, lymph, and secretions of animals, and
to the so-called antibodies which develop in the fluids of organisms
during the development of immunity.

Jost thus relates the cause of self-sterility to a lack of differ-
entiation, which develops quite independently of the hereditary
functions of germ plasm and which is quite individual, and in
development is purely epigenetic. The assumed similarity in the
fluids of the sex organs and sex cells exists solely because they have
developed on the same plant.

Morgan’s (’?04, ’10) noteworthy work on the causes of self-
sterility in the usually self-sterile animal Ciona intestinalis gives
data which Morgan considers as evidence that the failure to self-
fertilize is due to cytoplasmic relations established in the indi-
vidual. Morgan’s theory of sexual fusion is a chemical one; the
actual entrance of the sperm into the egg is held to be a result of a
chemical reaction which occurs at the point of contact, and that
this reaction is dependent on a constitutional dissimilarity of the
gametes involved. His results are in close harmony with his
general views that self-incompatibility is, in Czona, due to physi-
ological processes quite individual in development and cyto-
plasmic in action, and that germ cells may be decidedly influenced
by such individual conditions irrespective of their own particular
idioplasmic composition.

For the experimental studies the eggs and sperms were removed
from the animals and the results of self- and cross-fertilization
were studied in sea water quite free from influence of body fluids
and with a relatively small amount of body tissues involved in
the form of testa cells adhering to the eggs. Here, it would
appear, the processes of fertilization may be in some respects
simpler than in the higher plants where the relation of pollen
tubes and tissues of pistils precedes the fusion of sex cells. Morgan
was unable to remove the self-immunity of eggs to the sperm of

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 349

the same individual by the use of ether, by changing temperature,
or by using various chemicals specially influential in altering
surface tension of the eggs. Experiments to determine if such
incompatibility could be acquired through transplantation were
likewise negative. It was found that body fluids inhibit all
fertilization evidently from causes quite different from those
operating in self-incompatibility.

In the artificial removal of eggs and sperm for these experiments,
the difficulty of securing good sperm was a source of much experi-
mental error, but Morgan’s results show that self-sterility was the
rule and that only to a limited degree does self-fertilization occur
in his strains, while general cross-fertility is nearly always possible
provided both eggs and sperm are in good condition.

Morgan considers that this self-incompatibility is due to an
absence of the necessary reaction between egg and sperm as the point
of contact and that such inaction is because of similarity. Con-
versely, the entrance of sperm into the egg in cross-fertilization
is due to the necessary reaction occurring as a result of differences
between the egg and sperm. Morgan very adequately points
out that self-sterility of this sort is not due to a similarity of
‘hereditary factors” carried by the sex cells, for they are haploid,
and are derived from parents that cannot be considered homo-
zygous. They can only be considered similar because both have
developed in the same individual. They are alike, he points out,
only because their protoplasmic substances have been under the
same influence.

It should be noted that Morgan points out that:such a con-
dition might also arise from inbreeding in which what is called
‘homozygosity ’’ might develop, giving similarity to the hereditary
complex. In 1904 Morgan suggested that although in all self-
fertilized hermaphrodite. animals and plants the common origin
of the sex organs involves conditions identical with those assumed
to cause self-sterility in Ciona, the action may be less marked
and not sufficiently strong to give self-sterility.

This analysis of the generalized term ‘‘constitutional similarity”
assumes that in self-sterile strains of plants and animals, in which
crossing is necessary for reproduction, the similarity must be
conceived to rest in individual cytoplasmic relations. This is the
conclusion that Morgan makes as late as 1913 in a general review

350 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

of the subject, although it may be noted that he is here inclined
to consider favorably the interpretations, especially of Pearl
and Correns, that these are definite Mendelian units accountable
for sterility and fertility. His analysis of their data is, however,
not critical and the view that cytoplasmic relations established
in a heterozygous individual are quite of the same nature as
similarity in heredity factors brought about by inbreeding is
equally suggestive that in the latter case the cytoplasmic relations
may also be the most important.

In rather marked contrast to Morgan’s results are those of
Fuchs (714), which show clearly that Ciona intestinalis at Naples
is self-fertile to a ‘‘very varying degree in different individuals.”
Fuchs, however, fails to see any relation of such phenomena to
that of self-sterility in plants like Reseda and Cardamine, chiefly
because he does not seem aware that here the same degree of
variation may be in evidence. Fuchs, further, considers that
cross-fertility is nearly absolute in his strains; the cases of poor
results are in general attributed to pathological conditions. His
actual results show, quite as do Morgan’s, that there is a wide
range of variation in the fertility of different crosses. \Fuchs’
experiments are scarcely convincing on this point as no adequate
number of individuals were tested with two or more individuals.
Numerous very critical experiments were planned to test various
phases of the physiology of fertilization in Czona, but the number
of tests made were most frequently too limited for conclusive
results. Furthermore, these experiments as well as those of cross-
fertilization were made with individuals whose self-fertility or
self-sterility was not determined. The results, however, suggest
that the egg and the ovary extracts, and the blood of individuals
when added to sea water containing eggs and sperms of two
different individuals increase the percentage of eggs fertilized.
It is suggested that the eggs of self-sterile individuals give off some
substance that inhibits the sperm of that individual; but one experi-
ment was made to determine if egg extracts of an individual B inhibit
the action of the sperm of B on eggs of A (Fuchs, table VIII),
but the result shows no such action. In this experiment, how-
ever, it was not determined whether A or B were self-sterile. The
influence of egg extracts on self-fertilization and cross-fertilization
between animals of similar or of different grades of self-fertility

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 351

is not reported. And it does not appear that tests similar to
those that Lillie has reported were made for the operation of any
auto-agglutinins or iso-agglutinins that would give some clue to
the intricate relation of self- and cross-sterility and fertility, and
for which such a hermaphrodite as Ciona seems especially favorable.

Neither Darwin, Jost, nor Morgan (including his work of 1910)
was fully aware of or took into consideration the fact that physio-
logical relations may operate to prevent cross-fertilization between
certain members of the same variety or strain (not involving the
so-called illegitimate pollinations in dimorphic or trimorphic
plants). That such may be the case is, from our present knowl-
edge, suggested by the results obtained by various early investi-
gators. Darwin (’68, pp. 169-170) states that it has long been
known that several species of Passiflora do not produce fruit
unless ‘‘fertilized by pollen taken from a distinct species.’ From
the evidence pertaining to Passiflora alata it seems highly probable
that certain cases of cross-incompatibility arose. In respect to
Gladiolus hybrids (pp. 172, 173), it is stated that “certain varieties
would not set seed although pollen was used from distinct plants
of the same variety, which had, of course, been propagated by
bulbs, but that they all seeded freely with pollen from any other
variety.” Focke (?90 and ’93) found that in Lilium bulbiferum
all plants of the same clone were cross-sterile, but that sister
plants of seed origin were fully cross-fertile.

In the production of fruit, especially in pears (Waite ’95),
plums (Backhouse, ’11), apples (Lewis and Vincent ’09), and
cherries (Gardner 713), it has quite generally been known to
fruit-growers that certain varieties were “‘self-sterile,’’ others
‘partially self-sterile,”’” and others ‘‘self-fertile.’ In the self-
sterile varieties the self- and cross-fertility among plants of the
variety may be so feeble that the planting of other varieties as
pollinizers is often practiced. In these studies the horticulturists
have determined the more general facts that pertain to practical
results in fruit-growing. Aside from the fact that the propagation
of these varieties is vegetative the physiological requirements for
fruit development further complicate the processes of seed de-
velopment, but it is very evident that quite independent of these
factors a very marked physiological incompatibility is in evidence
in these varieties.

352 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

Waite (’95) has shown that 22 varieties of pears are self-sterile
(unfruitful) and 14 are self-fertile. In many of the “‘self-fertile”’
varieties the fruits formed were entirely seedless, while fruits on
the same tree resulting from intervarietal pollination were well
supplied with sound seeds. In these experiments no essential
differences were noted in intervarietal fertility and fruitfulness.

Lewis and Vincent (’09) report 59 varieties of apple that are
self-sterile, 15 varieties that are self-fertile and 13 varieties that are
partially self-fertile. The Spitzenberg variety, for example, was
found to be feebly self-fertile, giving only about 3 per cent of
fruit with self-pollination. While no marked cases of intervarietal
sterility were found, there were rather decided differences in the
degree of fruitfulness. In many of the “‘self-fertile’’ varieties the
fruits were seedless. In these varieties, especially, the number of
seeds was increased and the quality and size of the fruit were
decidedly improved by intervarietal pollination.

All varieties of the sweet cherry, 16 in number, which were
tested by Gardner (13) were found to be self-sterile under enforced
natural self-pollination; 3 per cent was the highest ‘“‘set’’ of fruit
obtained from any variety. Under field conditions there is
evidently greater fruitfulness, although for purposes of fruit-
growing the varieties are ‘‘ practically self-sterile.”’ It was found
that at least three varieties are strongly inter-sterile, necessitating
the use of other varieties as pollinizers. It is also to be noted
that in a few cases reciprocal intervarietal crosses gave different
results; crossed one way they were sterile, but crossed the other
way they were fertile. The relation of intervarietal sterility to
descent is considered by Gardner. It was determined that seedling
trees in and about orchards of self-sterile varieties are often good
pollinizers to these varieties. Also from the known pedigrees of
several varieties it appears that a seedling variety may be inter-
fertile with its seed-parent variety, and that two seedling varieties
derived from the same variety may be inter-fertile to some degree.
The inter-relationships in respect to sterility are shown to be
widely fluctuating and, Gardner concludes, do not show correla-
tion with closeness of relationship. While environmental factors
are influential in the production of fruit, the marked self-sterility
of individual plants, the intra-varietal sterility, and the cases of
inter-varietal sterility are not due to ‘“‘any inherent weakness of
either ovaries or pollen grains’”’ (Gardner 713, p. 17).

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 353

All these cases are especially interesting in showing that self-
sterility may be so strongly persistent in large numbers of offspring
propagated vegetatively that in practical fruit production proper
pollinizers are necessary. In the cases of intervarietal sterility
reported by Gardner, we see a phenomenon quite identical with
that which Correns reports, almost simultaneously, in Cardamine,
in which the possibility of cross-sterility between sister plants of a
seed progeny was proven and the interrelations of sterility studied
in a pedigreed seed progeny.

The studies made by Correns (’12, ?13) places the emphasis
on the phenomena of cross-sterility which he made the basis of a
theoretical explanation of sterility (due to physiological incom-
patibility), which is decidedly different from that announced by
Jost.

Correns (’12, ’13) successfully crossed two self-sterile plants
of Cardamine pratensis which he had obtained from different
localities. The sixty plants reared from this cross were, Correns
states, completely self-sterile, although in his tables it appears
that at least one of them did set seed to self-pollination. These
plants exhibited all degrees of incompatibility when crossed among
themselves and with their parents. Correns attempts to explain
the phenomena of both self- and cross-sterility observed in Carda-
mine by the assumption of chemical substances, which he calls
“line stuffs’? and which he assumes are represented in germ cells
by units which segregate in germ-cell formation. This is a real
attempt to solve the problem of the nature and the inheritance of
physiological self- and cross-incompatibility and hence deserves
most careful consideration, especially as it represents perhaps the
best Mendelian interpretation that is possible.

The sixty sister plants derived from the cross between plants
designated as B and G when pollinated with pollen of these parents
fell into four classes: some were sterile to pollen of B and G, and
Correns hence concludes these have the constitution BG; some
were fertile with pollen of B, but sterile to pollen of G, and these
have the constitution 0G; plants fertile to pollen of G and sterile
to B, have the constitution Bg, and those fertile with pollen of
both B and G have the constitution bg. The parent plants are
hence assumed to form four kinds of gametes with respect to the
line stuffs involved; thus B produces gametes B and 0b, while G

354 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

produces gametes G and g. Two gametes, Correns assumes, can
combine only if different, hence the four classes of progeny BG,
bG, Bg, and bg, judged by their fertility or sterility with the
pollen of the parents.

It is obvious that this interpretation is based on several as-
sumptions quite secondary to the general doctrines of Mendelian
behavior, and quite limited and individual in application.

The diploid constitution of the parents is represented by Bd
and Gg. This is the usual notation for the presence and absence
of an assumed factor. Here, however, ‘‘B”’ is the line stuff
derived from one immediate parent and ‘‘b’’ is quite another line
stuff from the other parent, but assumed to be inactive in the
plant B. The same is true of “G” and ‘‘g.” In the matter of
notation, it would be more correct for his interpretation if Correns
represented these different substances by a different letter repre-
senting the composition assumed as Bx and Gy.

Correns treats the offspring belonging to the classes Bg and bG
as if they also build only one active line stuff. The class BG,
however, builds two line stuffs, as both B and G are assumed to be
active. The assumption is that some plants may build two active
line stuffs, others only one. Furthermore, the line stuffs 6 and g
(or x and z) assumed to be inactive in plants B and G are trans-
mitted to offspring, at least of the groups Bg and 0G in the inactive
condition. It is not explained what line stuff the plants of the bg
class build, but as these plants are said to be self-sterile, either one
or both of the same line stuffs which were inactive in the parents
and which were inactive in the sister plants Bg and 6G now be-
comes active or other active stuffs are operating (Correns even
considers the latter to be possible).

Chance combinations between all gametes are, it is assumed, not
possible. No plants of the combination BB, GG, bb or gg are
assumed to appear as offspring of Bb or Gg. The plant Bd pro-
duces two kinds of pollen, B and 4, but is self-sterile to both; there-
fore, the active line stuff B of the pistils inhibits pollen tubes with
B and also b (which is another line stuff in inactive condition), or
the inactive stuff } is inhibiting the b pollen tubes. It should be
noted, however, that later (p. 421) Correns classifies the progeny
of the cross bG < Bb in four classes, Bb, BG, bG, and bb, so that
here “‘b”’ eggs in the plant 6G can be fertilized from 6 pollen or B

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 355

pollen of plant Bb. This sort of combination is assumed not to
be possible in the previous crosses. Why the plants dG and Bd
cannot likewise be fertilized by their own 0 pollen is not clear.

These discrepancies and assumptions of special conditions arise
in part from the interpretation that sterility is concerned only
with the interaction between the pistil, composed of diploid cells,
and the pollen tubes with cells of haploid constitution. Yet in
regard to the interaction, all of the pollen grains are treated as
if they were alike, although a single grain is assumed to carry only
one line stuff and to transmit this in purity.

Correns’ results are excellently tabulated, but the number of
seed per capsule is not recorded, nor is there given a standard of
optimum fertility. The development of the capsules is judged
and graded as nichts, einsamig, sehr schlecht, schlecht, ziemlich
schlecht, ziemlich gut, sehr gut, and gut; or beschadigt. It is not
clear that capsules classified as ‘“‘schlecht’’ always contained seed,
or that there is any development of completely empty pods.
A study of the data given, however, shows that all degrees of cross-
fertility and cross-sterility appeared. This may be illustrated
by some of the results of pollinations from plant B as recorded in
table 1, p. 403.

Female parent No. of flowers Results
2 qu 5 alle sehr gut
all 5 alle gut
la 10 6 nichts, 3 ziemlich gut
1k 9 7 nichts, 1 gut, I schlecht
Iu 10 g nichts, I schlecht
ly 13 12 nichts, 1 sehr schlecht
2p 10 alle nichts bis auf I einsamige Schote
2 ab 12 alle nichts

Correns realized that such results are difficult to classify.
“Die Ergebnisse entsprachen nicht ganz meinen Erwartungen;
sie waren nicht so eindeutig scharf, wie ich gehofft hatte, und
zwar in doppelter Hinsicht’’ (p. 400), and also that there is
‘“‘Grossere Schwierigkeiten fur die Beurteilung der Ergebnisse
bot das ‘schlechte’ Ansetzen; wenn z. B. in einer Schote nur einige

wenige Samen oder nur einer ausgebildet wurde” (p. 401). Yet
- Gorrens does not fully recognize that a feeble fertility or a partial
sterility may actually exist quite apart from any or all artificially
unfavorable conditions and errors in manipulation. The data

356 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

show that of the 60 F, plants pollinated from the parent B, 46 set
some seed, although in Correns’ grouping only 32 are credited as
being fertile: pollen from the parent G gave some seed in 52 cases,
but Correns credits 30 as being fertile. To summarize in tabular
form the ‘actual results and the grouping as given by Correns:

From data Classification of Correns
Plants fertile in some degree to both B&G 39. 16
“c ‘ce “c “i 46 “cc B only af 16
ae ae ae ae ae ae G ae I2 14
fs “to neither B nor G 2 14

Correns’ whole interpretation rests largely on the classification
of the plants into nearly equal groups, to obtain which it is neces-
sary to consider 35 cases of feeble fertility as fully sterile and 11
cases of no fertility as fully fertile.

In table 3 Correns gives the results of all possible reciprocal
pollinations involving eight of the progeny and both parents.
One pair of reciprocals involving parent Bb and offspring of the
BG class were sterile; but in another pair (B with z m.) both were
fertile. The pair involving Bb and Bg were both sterile; hence
the “g’”’ pollen of Bg was inhibited by B or b of the stigmas of Bd;
and in the reciprocal cross, “6’’ pollen was inhibited by the alto-
gether different substances “B”’ or ‘“‘g’’. Of the two pairs of
reciprocals involving parent Gg and offspring BG, one pair were
sterile and one pair fertile to some degree. Three pairs gave
different results: Gg X 6G (plant 7 ae) was sterile, the reciprocal
feebly fertile; Gg X Bg (plant 2 6) was sterile, the reciprocal was
strongly fertile; Gg X bG (plant 2 e) was sterile, the reciprocal was
feebly fertile. Of the other thirteen pairs of reciprocals each pair
gave the same result; the zmteraction between pistils and pollen was
the same irrespective of the fact that no two of the plants concerned
possessed the same combination of line stuffs.

Correns made over 700 of the 3,540 possible cross-pollinations
between the 60 offspring and these were well distributed to give
adequate tests of the interrelations of the four classes. The plants
classed as bg which should, according to assumption, be cross-
fertile to all other plants met the expectation more fully than On
other class, as out of 341 cross combinations involving bg plan ee
as one or both parents only 48 were fully sterile. Combinations _
involving BG plants with Bg, bG, or BG plants should be sterile;

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 357

of 207 such combinations 48 were fertile in some degree. There
were wide variations, however, in the individual behavior of the
various group combinations, as can be illustrated by the following
summary compiled from tables 8 and 9:

47 cases of (bg X BG), should be fertile, 1 was sterile

39 (SCG BG lent. ‘“‘ sterile, 1 was fertile
60. ye (Ge. & bG); eh ‘‘ fertile, 4 were sterile
sot es 8b S< 5B), if ‘‘ fertile, 10 were sterile
som F(bG x bg); fs ‘‘ fertile, 20 were sterile
Bore” MAC BG XG), a ‘“ sterile, 28 were fertile
ys) 8 28 (OG XX BG), a ‘* sterile, 30 were fertile

In general, as in the crosses with parents, the cases of cross-
fertility exceeded expectations; out of 299 cases that should have
been cross-sterile, 113 combinations were fertile. In the tables
Correns includes data on self-pollinations of 13 plants and of these
it appears that three (2d, 2e, and 2 h) were partly self-fertie; in
five of the plants reported self-sterile only two flowers were tested,
in two only three, in one plant four, and in one plant six. No
doubt a larger number of self-pollinations would reveal more plants
self-fertile. It also appears from the data of table 8A that at least
one plant included in the tables (z c) was not even tested for self-
fertility. There is no data given regarding the self-sterility of the
other 46 plants of the F; generation.

Correns’ results are important in establishing the fact that cross-
incompatibility may exist between closely related plants which
also exhibit self-incompatibility. His contention that both self-
and cross-sterility are due to the same kind of interactions is
suggestive. That this incompatibility depends upon and exists
between line stuffs whose presence depends on an ‘‘anlage’”’ which
is inherited and which follows the Mendelian law of segregation is,
however, not supported by his evidence. It is plain from Correns'’
data that such a simple explanation is not adequate, even if we
believe that incompatibility is largely dependent upon chemical
compounds and definite processes.

These results show very clearly that there are wide variations
in the degree to which cross-sterility exists among different plants,
that conditions giving sterility are not identical in all plants and
that when complete cross-sterility exists it may be quite indepen-
dent of germ-cell differences resulting from reduction divisions.

358 |= MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

It should be noted that Baur (’11, p. 212) had already suggested
a simple Mendelian explanation for the behavior of self-sterility.
Antirrhinum molle, which is ‘‘streng selbststeril’’ when crossed with
the self-fertile species A. majus, gave, he reports, only self-fertile
F, progeny while the F, consisted of both self-fertile and self-sterile,
the former being in the greater number. Baur has not published
any data regarding the number of plants, the variations which
they exhibited, nor is there any evidence on the very important
questions of self- and cross-sterility in the species Antirrhinum
molle. Lotsy (’11) has, however, grown Fy», generations of these
hybrids and reported that such wide diversity exists in their self-
fertility and self-sterility that at least in certain lines of descent
no two individuals can be considered the same. Compton (712,
13), likewise, supports the view that self-fertility (in Reseda) is a
simple Mendelian dominant over self-sterility. He considers
that it is even simpler than Correns conceives it to be in that the
self-sterile plants are really recessives possessing absence of sub-
stances either stimulative or nutritive to the growth of the pollen
tubes, and that self-fertile plants, which do exist, may or may not
breed true. Compton’s conception of. the simple presence and
absence of a substance stimulating growth attempts to account
for self-fertile and self-sterile plants, but is hardly considerative
of any phenomena of cross-fertility or cross-sterility, especially
among plants self-sterile. Compton has not published the data
of his investigations.

At this stage in the study of the phenomena of self-sterility
East presented data showing that self-sterility may be almost
complete among a culture of hybrid plants which exhibit feebly
if at all the phenomena of cross-sterility. East, although formerly
considering that Nicotiana alata grandiflora and N. Forgetiana,
together with other Nicotiana species, are fully self-fertile, finds
(715) that cases of self-incompatibility may have appeared in at
least one of these species and that from one cross four generations
totaling over 500 plants were tested and found completely self-
sterile. When crossed among themselves they were almost com-
pletely fertile. However, from the data given by East, it appears
that no systematic crossings were made in the Fy, and that only
twenty plants of the F2, twelve of the F;, and ten of the Fy were
used in such crosses; with these, however, 289 combinations are

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 359

reported of which thirteen were sterile, and four gave less than
fifty per cent of the full fertility. Of the total of more than 500
hybrids of the several generations only forty-two were used in
intercrossing. While East admits that the evidence indicates the
possibility of ‘‘true cross-sterility’’ he is inclined to view the
partial or feeble fertility seen in four crosses as accidental. East
finds that in the self-pollinations, pollen germinates abundantly,
but the tubes show no acceleration of growth when they penetrate
nearer to the ovaries as do the pollen tubes in cross-fertilization.
This we may note is in accord with numerous observations made
by Scott, Muller, Darwin, Hildebrand, Jost, and Correns. Quite
in common with Jost, East considers that the pistils produce
stimulating substances, but further assumes that the secretion
of such substances is “called forth only by a gamete that differs
from the somatic cells between which the pollen tube passes.”’
According to this view self-sterility is largely an individual
matter depending on too great a similarity or a lack of necessary
constitutional differentiation which is in this particular quite the
view of Darwin, Jost, and Correns. The conception differs especi-
ally from Darwin’s in limiting the operating dissimilarity to the
pollen grains: the pollen must possess in its constitution at least
one hereditary element which is not present in the more complex
pistillate cells. No matter how simple or how complex a pistil
may be, pollen tubes will grow well, provided they possess some
different element. The view differs radically from that of Baur,
Correns, and Compton in assuming that there are no specific
factors, anlages, or determiners which are directly concerned with
fertility or sterility, and which are inherited as such. The in-
ference is that the ability to form the specific enzymes and stimu-
lating substances is present in all plants of the race or series of
hybrids. The production of the necessary enzymes in the pollen
tube and their subsequent action in calling forth secretion in the
pistil is conditioned by the one-sided dissimilarity as noted above,
and is a secondary property of the general hereditary complex.
The fundamental conception is, of course, that the germ cell
constitution is made up in part at least of definite units which
are anlages, either directly or in combination with other units,
for the expression of characters. This raises the highly important
question whether such units exist with anything more than rela-

360 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

tive constancy and purity. It is also clear that the assignment of
different and independent degrees of influence in the development
of sterility to the various assumed units would theoretically
account for any sort of fluctuation or variation in the individual
development of self-fertility. Such explanations, however, do not
add to the understanding of the actual chemical and physiological
processes and only very indirectly to the practical problems of
the effects of inbreeding and the development of highly self-fertile
races. It would appear also that this view limits the constitutional
differences to hereditary elements quite independent of any cyto-
plasmic relations that may exist, which in this respect is in accord
with the conception of Baur and Correns and Compton, but not
agreeing with the views of Darwin and Jost and Morgan. If this
be true, it is not clear why somatic cells of the pistil cannot react
favorably with pollen tubes if the former possess some element
different from the pollen; but as such a relation always exists and
most especially so with hybrids such as East reports, there would
be, from this basis, universal self-fertility.

East assumes that the tobacco hybrids are self-sterile because
none of the pollen grains produced by a plant possess any heredi-
tary element not present in the somatic cellsof that plant. But no
pollen of a plant ever does, unless there are vegetative mutations,
segregations, or other variations among the branches and among
the pistils and stamens of a plant, so the conception fails to account
for self-fertility, especially of lines breeding true, which is a wide-
spread phenomena in plants and which East has repeatedly in-
sisted is the rule in Nicotiana species.

From the reviews just given, it is evident that intensive studies
regarding the facts of cross- and self-incompatibility in plants
have been attempted only in the two cases reported by Correns
and East, and that even in these cases much desirable data were
not obtained. It is very obvious that before we can arrive at any
comprehensive conception of the principles involved, much more
evidence is needed. It is with especial reference to such data that
the writer here presents the results of studies with chicory (C7-
chorium Intybus) which pertain to the expression and the heredity
of physiological self- and cross-incompatibility.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 261

METHODS VOR valu DY.IN ‘CHICORY

This species is especially favorable for such a study. The
species is one of the Composites. All the flowers of each head are
ligulate; they are perfect and alike (see PLATE 30). The flowers
open almost simultaneously not only in a single head but in the
various heads (from I to perhaps 100) that open in any one day
on any one plant. In regard to anatomical development and
compatibility the conditions give absolute potential self- and
cross-fertility, the only exception in my cultures being a few plants
which have appeared that are impotent in some degree.

Furthermore, an individual flower head is normally open but a
few hours and all of its flowers shed their pollen at the same
time. As the various heads opening in any one day on a plant
or on different plants are quite uniform in this respect, differences
in the maturity of sex organs in these flowers are, it would seem,
as nearly absent as is possible in any plant.

The hour of opening and the period during which flower heads
remain open varies with the weather conditions and with the
season. During a warm sunny period in midsummer the pro-
cedure in the experimental plots at the New York Botanical
Garden is in general like that recorded for the 31st of July, 1912.
On this date, at 6:30 A. M. the flower heads were mostly open
but the individual corollas were not fully extended or flattened
out and none of the pistils were protruding through the stamen
ring. At 6:40 a few pistils were protruding (see PLATE 30, FIGS.
I and 4): at 7:05 the styles of these flowers were fully protruding,
but the stigmas were appressed to each other, a stage in which the
rough spiny exterior of the style and stigmas drags out consider-
able pollen; bumble bees and various other insects began to appear:
at 7:30 the stigmatic lobes began to spread (FIG. 7): at 8:00 the
stigmas of all flowers were fully extended and the lobes separated
and strongly recurving (FIGS. 2, 5, and 9), thus exposing the inner
stigmatic surfaces; insects were very busy gathering pollen: at
10:00 the petals began to wither, fade, and close in over the pistils:
at 10:30 nearly all heads were closed never to open again (FIG.
3 and 11). This sequence in development is shown in the heads
and individual flowers portrayed in PLATE 30.

On such a day, only the interval between 7:45 and 9:30 A. M.

362 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

can be properly used in manipulating cross- and self-pollinations.
In making controlled self-pollinations heads that have opened
under a bag are used. One head is removed with a pair of scissors
and the petals are cut away as shown in FIGURE 5. The group of
broken anther-sacs with the protruding stigmas is used to brush
thoroughly the inner surfaces of the expanded stigmas of attached
flower heads that have opened under a bag on the same plant.
Heads thus treated are tagged and the bags are replaced until a
later day. This method insures the distribution of a plant’s
own pollen on the stigmatic surfaces at a time when these are
fully exposed. The chief source of error is the chance that
winged insects, which are sometimes very active, may gain access
to a head while the bag is removed. To decrease such error two
persons have cooperated in the manipulations, one keeping a
constant watch while a bag is removed. When insects are ob-
served to alight on a head, which occasionally occurs, the head is
removed. Pollen may also be distributed by wind. That such
errors cannot be entirely prevented is obvious, and in some cases
the results seem to show that such an error has occurred. The
scissors used in cutting away the petals are dipped in alcohol
after a plant is worked and the hands of the operators are washed
in water.

In making crosses involving a seed parent known to be self-
incompatible, the method used is quite like that of selfing except
that flower heads from one plant are used as a source of pollen
applied to the flowers of another plant. Crossing onto a seed
parent that is self-fertile necessitates the depollination method
- described by Oliver (710). In testing the effects of selfing and
crossing, it was always the aim to use several heads on one date,
and if conditions allowed, to make the same combination on a
different date in the same season or even in different years until
at least ten heads had been treated.

Some cases of failure to set seed, especially when an entire head
soon shrivelled, were no doubt due to injury such as bruising in
handling or by contact with the paper bags or with twigs. Sucha
source of error was operating in all cases of fertility. The data
for heads of branches that obviously became broken or otherwise
injured were discarded.

In regard to the immediate development after pollination, there

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 363

appears to be no difference between heads that produce seed and
those that do not. The heads close and the petals wither as de-
scribed, and the mass of withered corollas break from the ovaries
and fall to the ground in about twenty-four hours in quite the same
manner. For a few days the young achenes show no differences,
but in the course of ten days or two weeks, those of. self-sterile
and of cross-sterile pollinations become shrivelled and light-
colored, and are not closely packed in the head; and such develop-
ment also occurred when the stigmas, stamens, and petals of
unopened flowers were shaved off with a razor, a procedure to
which a number of the parent plants of 1912 were submitted in
testing whether parthenogenesis occurs in Cichorium as it does in
Taraxacum.

In the later stages of seed development, it was in most cases not
difficult to distinguish the heads having viable seed nor difficult
to distinguish seeds with embryos from empty seeds. It may be
noted that as a single flower of Cichorium produces only one seed,
which is a somewhat conspicuous achene, the judgment of fertility
is simpler than is the case in plants which produce capsules with
numerous small seeds, some of which are nearly always empty
from various local physiological conditions not involving any
incompatibility between pollen and stigma. In determining the
result of pollinations, the tagged heads were inspected frequently
during the period of the ripening of seed. When a head matured
it was removed and the seeds carefully examined one by one,
and all that appeared to contain embryos were placed in a seed
envelope together with the tag belonging to the head, while the
complete data were recorded on the envelope. The tags were
collected from all heads that produced no seed and in which there
was no apparent injury of branches. English sparrows and gold-
finches were frequent in the Garden and through feeding on the
seed interfered to some extent with the seed collection. In nearly
all cases their visits were confined to heads that produced good
seed; their interference with manipulated heads, indicated in the
tables, involves in some cases the question of the degree of fertility
shown by plants. As all manipulations were recorded in a day-
book, the final data for any plant were readily compiled from this
record, from the envelopes and from the tags of seed collections
into the final form of a card catalogue.

364 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

It is not possible to judge with absolute certainty concerning
every seed as to whether it is viable or not. Davis (’15) has
shown that such difficulty exists in Oenothera, in which large
numbers of seed-like structures may not germinate and that there
is great irregularity in the time of germination of viable seeds,
which makes it desirable to employ special methods in growing
pedigreed cultures. In sowing seed of Cichorium, it is my method
to sow the seeds from each head in separate seed pans containing
sterilized soil. Theseeds are relatively few, thus far never more than
twenty-two fora pan. As soon as plants are well started they are
placed in pots and properly labeled, but the seed pan is kept for a
period of three or four months. Some irregular germinations have
been noted extending at the most over a period of about five weeks.

There were no seed sowings from seed collections judged as
viable that did not give some germination. As far as tested no
plant was judged as self-fertile that did not produce some viable
seed. Not all seeds containing embryos proved to be viable. In
the plantings of I915, for example, selfed seeds of twenty-one
plants judged as self-fertile were sown to the number of 268;
from these 218 plants were grown into the rosette stage and there
were about 20 plants that died or were killed by slugs soon after
germination. On this basis the viability of seeds which were
judged as possessing embryos was about 85 per cent.

RESULTS OF THE EXPERIMENTAL se etn

PHENOMENA OF SELF-COMPATIBILITY AND SELF-INCOMPATIBILITY

The experimental study of self-sterility in Cichorium Intybus
was begun by the writer in 1912, when it was found that numerous
plants of both wild and cultivated strains failed to set seed when
self-pollinated under control. The investigations were originally
planned to test the inheritance of flower color and other char-
acters in wild white-flowered plants by inbreeding, and by crossing
with blue-flowered plants of both wild and cultivated stock. In
1911, seeds were collected from three wild white-flowered plants
that were growing on the campus of the University of Wisconsin.
Later these plants, designated as A, B, and C, were dug up and
replanted in the breeding plots at the New York Botanical Garden.
The seed collected from these plants was sown in October, IQIT;

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 365

the seedlings were grown in pots in a greenhouse until spring,
when they were planted in the field giving sixty-six plants, twenty-
seven of which were from seed of the plant A.

In order to secure blue-flowered plants of a decidedly distinct
strain from that of wild plants growing in the vicinity of plants 4,
B, and C, there were also grown in I912 twenty-nine plants of a
cultivated variety, the seed of which was obtained from J. M.
Thorburn and Company (No. 4300, Catalogue of 1911) and which
had been grown by the firm of Ernst Benary of Erfurt, Germany.
The variety was the unimproved ‘“‘common”’ chicory grown in
various parts of Europe for salad. These plants are designated
as the E series. Besides being blue-flowered, the plants of this
series were decidedly more robust than the plants of the wild
strains. The latter were from 214 to 3 feet tall and were, as a
rule, scraggly. The plants of the cultivated strain were from
5 to 6% feet tall and possessed many more leaves and branches.
Both the wild and the cultivated strains exhibited wide variations
especially in the shape of the leaves and in the amount of red
coloration.

In the summer of I912, various crosses were made between
plants A, B, C, £3, and E22 using the depollination method
described by Oliver (’10). These plants together with about
thirty others were self-pollinated. The crosses, which involved few
individuals, were successful (see TABLE 2), but the self-pollinations

1Six seeds: evidently by experimental error.

366 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

In 1913, the plants grown in the previous year were retained
and several sets of seedlings grown from the crossed seed. These
plants were tested as fully as conditions permitted for self-sterility
and for fertility among themselves, and careful records kept of all
manipulations. The evidence that self-sterility was the rule in
these plants may be presented in table 1. Here the plant is named
and data given regarding the number of heads pollinated, the
number of dates upon which pollinations were made, and the
number of heads with no seed or with seed.

The results were very conclusive for these plants. The number
of individual heads tested is high, ranging from 10 to 40 for a plant.
The plants A, B, C, £3, and E22 were also tested in 1914 (as well
as in 1912,of which no record was kept), and, with the exception
of one head of plant C, not a single seed was produced.

Similar data could be given for other plants. None of the 29
plants of the cultivated common chicory (E series) nor of the 27
plants of the A series (progeny of open-fed seed of plant A) proved
to be self-fertile in any degree. Twenty-five other plants, progeny
of plants B and C, tested for self-fertility gave the same results.
It will be noted that further instances of self-sterility appeared in
the Fy, F., and F; generations. Furthermore, self-sterility ap-
peared as the rule in all the varieties of chicory grown at the
breeding plots. In 1913, about twenty-five plants were grown of
each of the following varieties: (1) Magdeburg, large-rooted;
(2) Magdeburg, strap-leaved; (3) Witloof; (4) improved spotted;
(5) improved red-leaved Treviso; (6) improved striped-leaved;
(7) long cylindrical-formed giant; (8) improved large-leaved; (9)
improved white; (10) large-rooted Silesian, and (10) common or
wild chicory (Barbe de Capucin). The seeds of these varieties
were furnished by the J. M. Thorburn Company, and was obtained
by them from France and Germany through their foreign agents.
Self-pollinations were tried on several plants (usually five) of each
of these varieties, but in no case was a plant found to be self-
fertile in any degree. Crosses between many of these plants
failed quite as is shown in TABLE I.

Careful examination was made of the mature pollen of many
plants, including all the plants mentioned in TABLE I. Very
few shrivelled grains were found and it was very evident that
impotence in respect to pollen production is not the cause of

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 367

the self-sterility in chicory. Neither are there in Cichorium any
apparent anatomical differences in the flower parts that would
constitute a factor in the question of fertility. The type of
flower is quite identical in all cases and the pistils and the
stamens are the same in position, and of the same relative
length both on a single plant and on various plants. All the
flowers with the exception of an occasional stray tubular flower
are ligulate and are quite identical in respect to general structure.

That the sex organs of self-sterile plants are effective for repro-
duction under certain conditions is conclusively shown when
crosses are made between plants that are self-sterile. As shown in
TABLE 2 the pollen of the plants A, B, and C, which was ineffective
in selfing, was productive of seed when used in cross-pollination.
In this and in succeeding tables there is given the number of
different dates on which the pollinations were made (under
Dates), the total number of heads involved, the number of heads
in which no seed were produced, the number of heads in which
seeds were produced, and the enumeration of the seeds obtained
for each head. Later tables include additional data which will
be readily understood. In all cases involving crosses the seed
parent is placed first in the combination as represented and in the
designation of each plant the known ancestry is indicated by the

numbers used.
TABLE 2

RESULTS OF SUCCESSFUL CROSSES INVOLVING SIX OF THE PARENT PLANTS

Record for heads pollinated
Plants ;
Dates | Total |Withnoseed| With seed Seeds per head
Ale Xo Bt 2 ae 2 12 2 10 QAO. 7a LO el Osm Leis
ES XGA tree 2 Ff oO 7 Pe eee (OhystorpadOy, 1p wiy/
aly Gn CR apes 4 14 3 | iit 2, OF Fy. 75.0% Op lbolss LZ, 20
COALS shee: 2 II O | II Sp Mills i, We lS Key Gite p, 1G}, 21)
LAUR SCTE hy es cll eee ae Hake Bae 3 9, 14, 15
Fig OKA! os | 2 6,9
DAU A 7 SN RMR eke ose 12 SON sop LOy Lss Lae kAap lA nla ely. 0.7
22K, Ay 522). rele em ces oe 12 GO 16,7 Op Oy WAG TA eh Ss calieaty7
Hie i CO Coa eceteh| Wier nease UA 5 J | 6 6G) 8. T2255, 16,15
(Sr ae Fave aves Peretti 402 '| 2 8, 14
CRP Oi Ie oats i's, cee aed eet 3 DL, 15; 19
se cpp A OLA en a Ae | 2 6 235575; Loy 1S

The crosses given in TABLE 2 which involve plants of the E
series were made in I912 and no exact record was kept of the
number of heads that were pollinated, as at that time it was not

368 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

known that the questions of fertility were involved. The data
pertain only to the heads from which seed was collected. The
successful results of reciprocal crosses show that the self-sterility
observed in these plants was not due to impotence of either pollen
or egg cells.

It should be noted that differences in the number of seeds pro-
duced per head, such as are shown in TABLE 2 and in all later tables,
are not due to the number of flowers in the heads. In 1914 counts
were made of the flowers in 153 heads borne on plant A ; the number
varied from 15 to 22 with the mean at 18. Data on 283 heads of
plant B gave a frequency distribution ranging from 13 to 20
with the mean at 15.8. A total of 395 heads of plant C gave a
range from 13 to 22 flowers per head with the mean at 18.9. As
shown in TABLE 2, the seeds collected per head varied on plant A
from 0 to 18; on plant B from 0 to 17, and on plant C from 0 to 20.
In these crosses the depollination method (Oliver ’10) was used
and some of the failures may very well be due to injuries or to
failure to make the proper pollination of all pistils. It is evident,
however, that there is a rather marked degree of fertility in these
crosses. The number of complete failures per head is low and
there are about half the heads that give a large number of seeds
and some heads produced close to the maximum number possible.

Self-sterility and self-fertility among plants of the F, generation.—
In the summer of 1913, a crop of plants was grown from seed
obtained by crossing the plants A, C, E3, and E22.. As these
plants came into bloom they were tested for self-sterility and the
investigations were continued during the summer of 1914 in the
attempt to test quite adequately every plant that lived through
a flowering period. The results are given in TABLE 3.

Of the 172 plants reported in TABLE 3 there were 157 (over
go per cent) that were completely self-sterile. Fifteen plants
set some seed to controlled self-pollination: some of these as
(E3 X A) no. 4 and (£22 X A) no. ro were decidedly self-fertile,
setting seed in the greater number of heads; eight plants were
self-fertile in less degree, in that seeds were obtained in relatively
few heads (for example, see data for (A X E22) no. 2 and no. 4)
and in some cases as in (A X E22) no. 4 the number of seeds per
head was also low; there were five plants each of which produced
but one head with seed.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS

TABLE 3

DATA FOR THE SELF-POLLINATIONS OF THE F, PROGENY

369

Plant
(A X C)

INO: «Iie eae
ioe oe
. 4 a ae
NO Ae eee

Bo ante
4 Gee
OY gece
BON oie ta
% rs es ed
TOL ec.
(A_X &3)

INGIALE Sr
ye eee hes
a a ees
a oe

ey a
idem a leben Pe
ee ei! se
Pall si See
Ot eta ae

(£3 X A)
O; bee dete
Hy ee A ORS
Zedics

Base
MS eee
‘>. (Oemanee es
‘OO Vea es
. Saha
o Cs

OSs eee
MS BE np
eM Oder
{A X E22)

No’ ieeeeee
Bae
3 Fae Roe

5 ieee
Ot 6 eee
i Y ee
¥ $726. 8h
4 Qresees

LOS ee
Rees
EA Se
ape eee a

25,

Dates

Re NWR NSD SH

NY RNHW HOD

BN HR RR OW Com WN

DAWWwWN NUW SOOO

Record for heads pollinated

Total

se
PRO OUNUWUUwW

With no| With

seed seed
Z oO
5 (6)
5 io)
5 “0
6 I
By alee
10 is)
10 to)
II O
4 is)
16 to)
12 to)
8 io)
14 to)
10 to)
6 (6)
5 to)
5 I
6 (6)
8 oO
TZ io)
4 O
9 20
II (6)
26 4
4 (9)
5 (9)
4 fo)
5 io)
7 2
18 (6)
7 fo)
28 6
20 6
31 I
5 to)
II to)
21 is)
4 2
7 fo)
16 to)
12 is)
Il 6

Seeds per head

2, 3, 6, 7, 7, 8, 10, 13, 13, 13, 14, 15,
16,°17,.17; 10), 10; LO, 10; 19-5

pe oe ee en ee egw fey Se

Ze hy Sp iehO, visi) S io Fa atten agi
Fo Gets AAs Giese ARR hes

60 Oa, BAG OO 8K, 8 6 AO OA © Vig eletely 6 6 ¢ 6 0

Lu pea Opal Oss sside wean Joe elenes
46 other plants of this series were
self-sterile

Fertility
(%)

0.05

0.13

0.04

370 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

‘TABLE 3—Continued

Record for heads pollinated

Plant no, 2 | : | a
W With
Dates ‘Total ae seed | Seeds per head arya
(E22 X A) |
NOS teats ae 5 5 fahelter aX)
Se aA 4 Il 10 Dy Gye pei eae Bee cooks Sk atree ear eg 0.03
: Beg: I 5 Sruleee
a oe 3 15 15 On |
: Gasset I 5 5 One|
ae -
LOncaree I Spee Si. 16,360 Sal O: sate a acca ie ees 0.51
ee TARE ORE 3 HO |f 4) TEP WOR COR cen sts eter ota ates eat yok eke ea eae ae 0.04.
| | 10 other plants of this series were
| | self-sterile |
(CX E22)
INOS enrieer 4 | 15 i ae si Va ta A et sh EU one Fonen tee A A 0.05
Wo RFs hove II 24 Bil 8)» \POSRTA NADAS «yen voy denne orctcvsi pean 0.07

17 other plants of this series were |
| | self-sterile

(C x E3) 11 plants all self-sterile

(453 < C) 6 ae ae ae ae

ae ae ae ae

Series 14. 30 See TABLE 8

The intensity of the character of self-fertility may be estimated
for the self-fertile plants of this generation and also of the following
generations and expressed in terms of the percentage of flowers
which produced seed. Statistical studies have been in progress on
the variation and the heredity of flower number and from these
data the average number of flowers per head is quite accurately
known for all but three of the self-fertile plants that have thus
far appeared. Multiplying this average by the number of heads
concerned in the controlled self-pollinations gives a very accurate
estimate of the number of flowers upon which the percentage of
seed can be computed. The average number of flowers per head
for the self-fertile plants of the F, generation ranged from 17.1
to 20.8, and the average fertility computed, as just stated, for
these plants varied from I per cent to 51 per cent.

Some of the data, especially that when only one head produced
seed, may involve an experimental error. In the case of (A X
£22) no. 5, thirty-one heads produced no seeds, while one head gave
five seeds, a result that might have been due to experimental error
as well as to a low degree of self-fertility. In plant (A xX £3) no. 8,
one head out of eight set seed, in (H22 & A) no. 2 one head out

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 371

of ten, but the data compare very favorably with that for such
plants as (E3 X A) no. 6 in which four heads out of thirty-one
(proportionally about 1 out of 8) set some seed.

The thirty hybrids (series 14) between a plant of the ‘‘striped-
leaved improved” variety and a plant of the (A X C) hybrids
were all completely self-sterile, as is shown in detail in TABLE 8.

It is very clear, however, that some of these F, hybrids were quite
decidedly self-fertile, and the evidence is likewise strongly indicative
that varying degrees of fertility exist, giving plants that are to be
considered as feebly self-fertile.

Self-sterility and self-fertility in Fs progenies derived from seed of
self-fertile F, plants—Pedigreed cultures have been grown from
the seed of various of the self-fertile plants just mentioned, and
the plants constituting this F, generation have been selfed during
1914 and 1915 as fully as conditions allowed. The results are
tabulated in TABLE 4. In this table the designation of the plant
gives its pedigree; the portion in parenthesis, as (#3 X A), indi-
cates the grandparents, the following number is the number of
the immediate parent. Under the caption “seeds per head,”’ there
are indicated several instances of the removal of seeds from the
heads by birds. When there was reason to believe that such
heads had contained some good seeds, the record is simply given
as B; when the birds had left some seeds these were collected and
the result recorded, as for example, 1 + B, or 6+ B, ete. In
this table there is also recorded the color of the flowers as to
whether blue (B) or white (W).

It is especially noticeable that as far as tested the progeny of a
self-fertile plant are not all self-fertile. The plant (E3 X A) no. 4
was decidedly self-fertile (see TABLE 3), but of the 18 plants thus
far tested among its progeny 8 were completely self-sterile. The
series (E3 X A)-6- composed of four plants were all self-sterile.
Nineteen offspring of (A X E22)-2- were tested and of these 10
were self-sterile; one plant of this series (no. 2) was an abnormal
plant with a dwarf habit of growth and nearly all of its flowers were
almost completely cleistogamous, with the anthers mostly con-
tabescent. Besides being strongly impotent it was self-sterile.
The series (A X E22)-4- was composed of 3 self-sterile and 7
self-fertile plants, (A X E22)-o0- of 4 self-sterile and 2 self-fertile
plants, and (E22 X A)-10-— of 12 self-sterile and 11 self-fertile.

372 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

TABLE 4
DATA FOR THE SELF-POLLINATIONS OF THE F2 GENERATION

Record for heads pollinated °

5
8
Plant o
E
ky
(£3 X A)-4-
Series I
INosesteie aan B
a fae ce B
“<a Mone aie B
Be RR ee B
FE (Gee: W
Pky Ree B
ree The arse B
nig Ten eae B
Sale pee W
SEES tee ee W
OO. Sarg B
eS Gt RE I oe W
Series II
INiois ie ero c. B
BALMS ber eh 3 B
Toe B
sali be eee B
PLC erat B
bt a2@r as B
(E3 X A)-6-
INOume rociss | B
head ig oe B
Lum heer. B
cad Ota B
(A X E22)-2-
Noy tte. - W
ae B
Ae | LARA ae B
a Beds aa B
ne ec Poh W
OPE T Us B
Sie LORE W
aS a Re B
ve ie Deore B
i pete Se eee W
PEL ae a B
STO 5 Se a W
OA Oy (BAY ed W
Ta ee W
S HL aes W
S220. hie B
pile SNR | B
hi, eset ee B |
en) Ree B

Tt % not computed

=
BOdOnoofUnHM

a
oo0o°0 Jae oo even mooofrooroO NUS

o
COR a eae Ea Bll
s ° oo v |
Q | =a)
ore a
es
4 |x | a |
3 9), 0
9 2I; 4
i A |
2 5 |
2 4 4
2 Io | 10 |
Za 6 2)
2 6 6 |
at 7"
2 8 8 |
4 10 5 |
3 vf 2 |
2 6 Ba
2 5 ae
gs TAGs) abn
2 6 2
2 7 (6)
4 Xe eee
Z| 20) | 204)
21 4) 4,
I 5 J
2 | 16 | 16
2 10 2
2 Beit 3: |
2 TX .| LO |
2 5 O
i 7 3 |
2 10 oO
3 9 9 |
oe wipe a 5
2G 6
AP jh ails (ae ts
TL ecou LO
2) wre I
aes 8
2 12 | 12 |
z Il 3 |
74 vr Wp
2 8 8 |
} |

0o0@m00

Seeds per head sie
Zeiss Aa Thiet; 5 seve: Exerd = seas | 0.26
2,4,5, 9,9, 9, 10, 10, 10, 10, II, 12,
T2TAS 2ON2T aD Asset ee eae 0.43
MEOW i we soe e aha aie Ue Loe | 0.22
FS LOnel Or tale | ecnuss ecvone cceea meets 0.29
02) Baby tb te or aes T
2 (Be AA I octets aeaieas ene ee okey ae 0.13
i 0.03
3; LO MDI, ake eee eee eee 0.28
CR Neate at Oe ER aes bal seh wrth AA 0 0.21
GPR rer moo Fa he tae oe ant i ema reas gice ry S 0.50
Flowers abnormal, self-sterile,
impotent
3, 45 6; (6,°6; 7c ae ere 0.19
L,°3,4) (EL; Loe sce See ee 0.22
| Diss eyoswi0) >. Fie cele ah SRR EUS eee Cee ene 0.01
3, 4,'6;.7-+ By Oni aoem ee ae 0.32
| 25.3 y. 75 (Givin sn, wae ete tae a 0.16
5: 5910, 6) 75°75 .05 aa eee ieee 0.42
1,3, 6; 8,. 315 (Dee eee eee 0.15
t +B, 3, 4) 5,7» 9, £0, 10, 1, 14,
LO nis 3c'y «0's. tal eee ee ee 0.52
I, 2, 2, 2, 2, 0, Sincere es keene 0.17

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 373
TABLE 4—Continued
5 Record for heads pollinated
pee
Plant | B = = he Aid
E a ‘s E 5 = 8 Seeds per head ghia
(A X E22)-4-
No: tee B I 8 6 De Op LAR clei aoe baths ten kee yas tees 0.16
7 af Dee Bale oe oN. 8
") Saaae Wal so ra 8 Bases eG 75 MOV sate lay ahem « Ae 0.13
Beene B Roar lk oy e)
i Ont eee WwW | 2 7. 2 RE ESA Sar Guth acu eievna scan icra cats 0.22
aS, = eee B Baie lo | TO)! 0
ell yh UE WV ee 12 | 10 ENT OT SN LAN Wigs Oey mak ewced Sad nse a Sela 0.01
“PSO s aes Wit II a Sa es Bea 0S .aserothie o hoe? 0.12
tf LO eee B Bee \OTSZ i O Ae Ob Ts VO; 28 ecka oro SO tie nae 0.12
oO RYne ee B I 5 2 Eye ie 85 ool Baas A 5 i reirao ten iat fan cir 0.23
(A X E22)-9-
Nov tier B I 9 9 (o)
iy eee Wis 3 > lng! 13 co)
< es ae B I 4 4 O
gy Ss ight! B 3 13 A © | 5p PEs 2), 1208; T4y 14, 5515-22 04S
pe Oe Wirlca. Bahl +3 Met, 2, 202) 8, 3 and ay 4, 4B,
5+8B,5 +B, 6,7 +B, 8, 10,
TO teh shT bE ios acy eee 0.33
pew ct ae B I 8 8 )
(E22 X A)-10- |
Series I
Now, 22ers W | 3 9 oc <0
ot ote B 2 Tate welt fo)
“aw AG Seer B 2 TAS er (o)
Spee ass B ae ET 8 Zvi 25 Sr Ater tens wanes scion e ae 0.05
RL cS x We |, 3. 1% | 5x0 1 he ai PN eS POE Re MEN BRE os 0.02
i” See Wee aes ead ore 9 |: 4y 35) 6, G; 77-10;-40,, 10 0.16
On NE SG Bai-2 4 ee Sk Poms Rk ie gel SICA gaat each Baihel ee 0.18
RTOs nee W | it 6 6 O
4 Laer Wisinesen| iG: 6 fe)
pL De ate B BO ett et Tee O
Ia ae B 2 9 oO Qh} 13S, 0; 6): 758; B2; Avot seeks. 0.38
+.” BAe oe Wii) 2 7 4 Pi i San Me ee eee a » Meee ror ea 0.14
PTS. tee B I Son 25: [ane
Tip LOUe we WE 2 Hat Map gS Ea fo)
Series II
INOS ieee B 2 II 2 @: 357 3s- 45. 85°8, 10; t= Be 3 4-28;
aiy GenOteD, Sehr UDOT Penn a | 0.52
pt Outer B 2 9 9 )
ff US ee W*| 2 9 Gul Fa AWS, Bid dad eld seat and seat 0.13
GA Sie B 3 Bales (e)
elegans B 3 14 | 14 fo)
ee? ee Wit 5 2 RUN Te hie Bien AbnY cra a ake Giese ae ns be 0.06
pee Nae ais B 2 vere flare O
ak Sean W | 2 | 14] ©O| 14 13,3) 414s 5s 5, 6, 7, 8, 9) 9 12, 12,
hig le Oe or eer 0.41
Sao PELIG Wace. NV), err 6 I Sy Weyer, CN, Eo ue. + ae jens Vee sete 0.39

* Color of stamens variable

374 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The numbers of self-fertile and self-sterile plants are nearly equal
for most of the series, giving a total of 41 self-sterile and 39 self-
fertile plants. The latter exhibit, as in the case of self-fertile
plants of the preceding generation, degrees of self-fertility varying
from high to very low, the average per plant, determined as
already described, ranging from I per cent to 52 per cent.

The facts regarding the flower color of these F, hybrids are of
interest as evidence of the actual occurrence of self-fertility. All
the plants included in TABLE 4 are of the F, generation of crosses
between the white-flowered wild plant A and the blue-flowered
plants nos. 3 and 22 of the cultivated chicory (E series). The Fy
parents were all blue-flowered, the color being a light-blue chicory
with flowers frequently of a lavender-violet shade. The F»
generation recorded in TABLE 4 split up into 46 blue-flowered and
25 white-flowered plants. The shade of blue varied greatly among
the blue-flowered plants and of the plants classed as white-
flowered 3 showed a noticeable variation from the usual type of
white flower. The plants A, B, and C, and all the plants thus
far grown from crosses between them, possess flowers that are
pure white except for a decided and continuous blue stripe ex-
tending up the middle of each anther, making well-marked and
conspicuous stripes in the ring of anthers. This is also the case
in most blue-flowered plants in my cultures, although the stripes are
here usually somewhat more intense. Plants (#22 X A)—I0-,n0s. 7
and 8 of series 1 and no. ro of series 2, however, had flowers with
the blue stripes much reduced, and in no. 7 there were only faint
traces of them. Ina general grouping of white-flowered and blue-
flowered, the splitting of this Fy, generation in respect to flower
color does not very closely conform to the so-called Mendelian
formula for a monohybrid ratio. The splitting in this generation,
however, is indicative that the seed set by the -F; generation were
the result of self-fertilization and not due to parthenogenesis which
may have developed.

Self-fertility and self-sterility among plants of the F3 generation
grown from seed of self-fertile F, plants—In 1915 several pedigreed
cultures were grown from self-fertilized seed obtained from various
of the F, plants. The results of self-pollinations on these plants
are tabulated in TABLE 5.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 375
TABLE 5
DATA FOR THE SELF-POLLINATIONS OF THE F3 GENERATION
i) Record for heads pollinated
fo}
Plant 0 % = Say rg ve
E = = % | = Q Seeds per head eed
(A X £22)-4-1-—| B |
INOS We oo W | 2 2 z oO |
er tnt B I 5 5 () |
ot aera B 2 8 8 oO |
Gerace B Beelels 4) 1S Co) |
peso} 5 atts B 2 9 9 fo)
Oh Nee oe Naira a bone Te O
PEM Reva oat B 2 Lee Ne L7, fo)
MEO) ae B BOW EO. | LOS. °O
pe Omta ee B 2 TOs LO) On|
sa ee W }| 3 | HOM 16 O |
(A X E22)-4-3-| W | |
Nor see ae: Rls (3 le 2: a be ee hao ee ae em cS ER | oN,
pth ge op bes WWE) 2 5 I 7 WAN ie seter SN C he Diino Rel ee ES ah Gites | 0.26
Sara sere WWE |e 4 I BIND. eo MAles 24 vevic Mere cary Cee ace Ne O.1I
Seles W | 6 9 9 O |
Ep aea lercn eee NV | 2 7 5 PA et SSG ale OR AP IES eer SEETE Lam ov Se en ty 0.05
TO Fats Wiilieeas ||) EON) 3 Del ernie ao pl (oH 9b etal DLS Pa to DO ae | 0.2
ob a epee W)] 5 10 5 erent ice TD) aT Sn yee ee eS et 0.32
HOE aa NIV aie ree iit O |
(A X £22)-4-6—| W
NOU errer W | 2 8 8 fe)
PS ete W } 2 6 I 5 SOS ASTI O A Tea ry Sete oR cesar vie 0.31
igus Sah: evi Sh ea 9 BD isd or Sik 2 ea Oh. s yan Aire ksN ars 4 ae 0.06
MAE ch rd W | 2 6 6 fe) |
Bie inca at Web a! i 5 PN SAS Sic ARG RECTOR CEC Ol AES CRORES LOR | 0.10
Oa ere Wolpe 5 5 fe) |
“SLO WES ese | oo: 3 HOD) ST ho. pte ho alee ea acdc ne Uiraciciok: ok 2 | 0.13
(A X E22) |
—4-I0- B |
No, une eee B 2 TOW LO)s| ao |
Sl Sa ae WW ee Oy x9 O
ei Pea oe W | 2 2 =e Co)
(A X £22)—9-4—| B
INOn <20y52 B 2 9 9 fe)
NL be bd B I 9 9 oO
Bieler oceaee B I Ff 2 Fae Pate 220 all oy fan O hy eolee tae, ce Gi RSet rhepolonese 0.20
the ar Sisco B 5 7 6 Te MBL orca Bag Sete e ie OE teres cieesre | 0.01
Be OS. Bap eave cewie iol... 0 |
eee Tieks AN B SE || A Ca a LOTG hoa TRS Beer a Rue es. Oc eeRe ot et | 0.13
reLO! sce W | 4 iho al Oya [aes ir paren Ica nO a CO) excherne cee 0.17
tee Ley se B 5 II 4 eal | SBIR Cea ts eye dl Dyer cis eae ce | 0.20
peel 2a B 6) | ort ar6, (6)
SEO eee B I 6 6 (0)
eT ae B 6, | 16/76 ()
oe an Nee B 6 10 7 Bibel: Ticats ele he: Uae ec IS PORES Ieee, AP | 0.02

THE NEW YORK BOTANICAL GARDEN

376 MEMOIRS OF
B
8
Plant g “y ra eu ing
= 2 ao = oO
2)8|6 | 28/58
(A X E22)-9-5-| W
INOS ST tiie W | 2 9 5 4
Se ee oe | W | 3 4 3 I
sae ops cises Wi 4 5 O 5
ag OL ree W | 3 eI 4 7,
iy in eS Wie 5 fo) 5
Sat wcRu Te Wi] 5 9 (0) 9
oe ree Wil 3)9 | eL6oL6 te)
MEROLS aoe Wi! 5 13 9 4
e GOweaee W | 3 7 Ce) 7
Br aLOE saya W | iI 3 3 (e)
git 738 eee Ae Was) 24s || SLOM | a0 fo)
eM Sts Wr) 2°), 44 ora
ed BL or ee Val eee: 9 I 8
(E22 X A)
—10—-6-— B
INOS 3k at B 3 8 7 I
ne Mise B 2 4 I 3
(E22 X A)
—I10-7—- W
INOS VETet oe W | 2 zi 5 2
ie 2c ote Wille2 9 9 oO
Soe Tate ee Weis 9 9 oO
(E22 X A)
—10-8- W
INO, 9201-7. serer- Wii eealore |) 03 (0)
Uf aA ayes Walleeea 4 I 3
MAR tee Wiehe 2 2 oO
ata eeie W | 4 | 16 6 | 10
eon Benn Wa 2 A] Oo 4
ot LCE ee W | 3 6 6 fo)
eh AE ee ces Well Sao 9 9 Co)
ai oe Wala. ie 9 3
ed ae Wolisar il ALO 3 i
POL ays Hee a 5 to) 5 |
(E22 X A)
—I0—-I3- B
INOR mar 31." «: B 2 10 | 10 Ce)
jE CS oe B 2 Tiles ee (0)
3 ks eee B Z 9] 79 O |
CoM etc « B 3 II rade || a
oN Websters B 250) oa 4 7
Eh ae OMe B 2 TES ware fe)
mr fe) Ce | B 3s), Lae oO
tt Mipicteee | B 2 | TONGrO oO
ee hae Vg a i es ee
et AT Oly crea B 2 mite Mi 6
ou ate hi di B 2 99/9 re)

TABLE 5—Continued

Record for heads pollinated

Seeds per head

I, 2; 8, On23
1, 3) Ay Ag Oy 10, 13
5; 5) 6, 6
I, 4, 4, 6, 7 aie Bs 9, 9, 12, 13

I, I, 2, 3; 4, 4, 5s 12

wlsieteieile ic eles vc wipe as = 0 s.0 » w o"ets @ eee

Siialevouns) bite o\'ny'e eos \e. alee! wos, eo see

piolete) eels elie sce e 8 ele fe te ele (ln e) Sas, eer

l1,2+B,3+B

| 2, 4, 5; 8, 8, 9, 9; 10, 10, II
|2+B,4+ 8, 4,4

eee eee ewer eee eee

je a.le 18,0, ¢ 2° 6 8) 5, vps; 6 60 0 0 'e (bk C1 Bip (e
Hie cle elvis oiete 0 b's sees

\2+B,3+B,3+B,3+B,4,
6, 6, 9, B, B, B
rea Oy

¢ a, 6 eS Silioce: eter els Suse
|

t 6.8 @ 59 oe 37061856

4, 6, 6, 7, 7, 10

Fertility
(%)

0.07
0.05
0.34
0.29

0.37
0.46

0.03
0.36

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 377

TABLE 5—Continued

A glance at this table shows that the families in the third
generations exhibit much the same sort of behavior in respect to
fertility and sterility as did the preceding generation. No series
in which more than two plants were grown was composed of plants
all of which were self-fertile. One series, (A X E22)—4-I-, was
composed of 10 plants all of which were self-sterile; (A H22)—4-3-
was composed of 2 self-sterile and 6 self-fertile plants, and (E22
< A)—r1o—13— had 10 self-sterile and 6 self-fertile plants. Taken
as a whole, there were 46 self-sterile and 43 self-fertile plants;
48 per cent of the plants were self-fertile in some degree. Of the
preceding generation 39 out of 80 plants were self-fertile, a per-
centage of 48. In both generations, considered as a whole, the
number of self-sterile plants was slightly greater than those self-
fertile, but the ratio of the two was the same.

In respect to the degree of self-fertility exhibited by individual
self-fertile plants of this F; generation, as judged by the seed set in
the controlled self-pollinations, there were all degrees ranging from
high self-fertility (70 per cent in the plant (A * E22)-9-5-— no. 12)
to very feeble self-fertility, both in reference to percentage of’
heads giving seed and to the number of seeds in the heads. On the
individual record the different plants exhibit varying degrees of
self-fertility quite the same as was seen in the F, and the F»
generations, but with a few plants with a higher percentage.

378 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Here as in the F, the inheritance of flower color is evidence that
seed-setting is the result of self-fertility and is not due to partheno-
genesis or to stray pollinations resulting from experimental error.
Six of the series were from F, white-flowered plants and all of these
were composed of white-flowered plants, although it should be
stated that there was considerable variation in respect to the
development of blue stripes on the anthers. The fact that Fy,
white-flowered plants gave only white-flowered progeny is evidence
that the seed from which they grew was not the result of acci-
dental cross-pollination. The five other series of the F3; were
from F, blue-flowered plants, and, with one exception (which is
series (H22 X A)—ro-6- of only two plants), the progeny split
up, giving a total of 33 blue-flowered and 8 white-flowered plants.
This we may also consider as evidence of self-fertilization.

Summary of the Fy, F., and F; generations——For purposes of
summary and comparison the data for the three generations and
for certain families are presented in TABLE 6. Here the frequency
distribution is given with the plants grouped in classes on the
basis of their self-fertility; the average fertility for the self-
fertile plants and for the entire generation or series is computed
from the actual percentages already given in TABLES 3, 4, and 5.
One of the F., and one of the Fs self-fertile plants are not included
in this distribution because data on the seed number are not
complete due to the gathering of seed by birds. It is fully recog-
nized that a larger number of pollinations might change the
results in numerous cases, that plants which appear self-sterile
may in reality be but very feebly fertile, and that some of the
seed-setting in cases of very low fertility may be: due to stray
pollinations. The number of plants in the F, and the F3; genera-
tion is nearly the same, and the methods of manipulation used
were quite identical, so it would appear that such a comparison
can quite properly be made.

In the first generation, 15 plants out of 172 were self-fertile in
some degree; the average percentage for the 14 plants upon which
flower data are available was 11.6, and the percentage for the
entire generation was 0.94. The F, which was grown from self-
fertile parents and in which selection for self-fertility first appeared
gave 39 self-fertile plants and 41 self-sterile plants; the average
fertility (of 38 plants as figured) is 21.9 per cent and that of the

STOUT: . POLLINATIONS IN CICHORIUM INTYBUS 379

entire generation is 9.9 per cent. The third generation gave 46
self-sterile and 43 self-fertile plants; the average fertility of the
generation is 9.9 per cent and that of the self-fertile plants is

21.1 per cent:
TABLE 6

SUMMARY OF F;, F2 AND F3 GENERATIONS

: Total | Frequency distribution. Per cent fertility. lAveragel «ave
number) ap Pe Lae Le ra fertily | fertility
of nf OSKRAaARSRRRESORE fertile | ofall
| plants ho 4% “ ro oe a a 2 HO 3 S ~ plants | plants
Biisiéa a ener | | UREA sty ERS HOTS Ai et Mi 1 = at O.P nO 0.0094
PAIRS bomerc yo Oo bea o ABN PSBOniN4AIn b5" 1-16, Tiaisae 2) AME Thies a O21 OH10.099
[DEE NS EE in c's Sod o DOE Bar elt 0 G7 3 ee oS Ae ee ea Ore L020
Fy, Babette erase tl 34.0 \244 227 14 O12 8 SOA et sls = lg O28 99 10.074
Pipe eo Nest Ss obs Sa Mors 10.48 |
Fo (E3 X A)-4- |_‘18* Q Seg) 24 Tee Dae ND 0.26 |0.138
Fy plant (A.x £22),No. 2) — a 0.06 |
Fy (te iiee) =e | EGh LOI? eg a Pes bo ae —| 0.24 |0.112
Rie tee) NOU A Ce aes oe ee is 0.04
F. (Ane iee 4 10 | BOOST) = SPST a ad a a Same 0.141 |0.099
F; (CLO BEE Cole een ae ee ge hora a hare ee OF Si Ey,8) 1S 0.000 0.000
a ae | et) Dy ea at Oe = =| 0.206 |0.155
i —4-0-| 7 Pies Sn Aeon 8 ame oe Gee os ee FL | 0.150 0.085
“ -g-10-| 3 ge ene ae = Boe meee Sow ee 0.000 0.000
Summary..../.026+>-| BS% | FOU 6 Bho 15 a Ow ONe a aes eee | 0.201 0.074
F, (E22 X A) No. 10| — [ps ee ee ee x-=--\|o.51 |
Fs (H22 X A)-10- Bay AT) ey 2 oe iene 2: Ne Vio at ae ae 0.197 0.094
F3 Gina eae) Sat | Om BH MeN Oy Me I» EP I igo oo Tey eke 0.070 0.070
- i. i Bye CON Nar We eee eae og ce agent Tp eet a 0.040 0.013
3) ie eel Lr |} we Ae ee ok ae Me eee Lo ae aad | 0.218 |0.121
ce Fi STEN VEO LOR Ty re aia ed hae ie —| 0.286 0.107
2 ip -I0-I4-| 5 CN era Met cata teat phon + eth Ee | 0.120 0.048
Summiaryc sesceees egos ist gO) Glenaue i diel celeron =| On20d (0.093
| )

* One self-fertile plant not included in frequency distribution or in averages.

It is quite evident that there is close agreement in the F, and Fs
generations both in the proportion of self-fertile plants and in
the average percentage fertility of the same. In both respects
these generations are decidedly higher than the Fy. A glance
at the distribution shows that in all three generations the distri-
bution is decidedly skew and rather irregular, with the largest
number of plants in the self-sterile class and in the classes showing
low self-fertility. In the Fi there were only two plants having
higher percentage of fertility than 13 per cent, and these show

380 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

48 per cent and 51 percent. In the F, and F; there was a more
general and graded distribution between the extremes, but in
the F; two plants exhibited a percentage of 56 and 70, the latter
being a decided advance over any plant of previous generations.
Considering the three generations together, the frequency curve
becomes more regularly skew with large numbers of individuals
in the self-sterile class and fewer numbers in the successive classes
leading to higher self-fertility. While the average percentage of
the I; is not higher than that of the F2, there are certain plants
with decidedly increased self-fertility.

A further point of considerable significance in respect to the
heredity of self-fertility pertains to the relative behavior of families
derived from parents which had decidedly different degrees of
self-fertility. Progenies of the two plants of the F; showing high
self-fertility were grown. Of 18 descendants of (E3 X A) no. 4,
only 10 were self-fertile with an average percentage of 26; for the
9 for which data were secured 1 plant showed a fertility of 50 per
cent and another of 43 per cent. From (E22 X A) no. ro, in an
F’, generation of 23 plants only 11 were self-fertile with an average
percentage of 19.7 and with no plant as strongly self-fertile as the
parent. The F; progenies continued from 5 of the F, plants of
this family, as summarized in TABLE 6, gave rather irregular results,
but with the average of each series decidedly lower than that of
the grandparent. The total averages are 20.1 per cent for the
self-fertile plants, and 9.3 per cent for all plants, which is only
slightly above that for the entire F,, F,, and F; populations.

In comparison with these, the progenies of plants exhibiting low
self-fertility showed no appreciable differences in fertility. For
example, the progeny of (A X E22) no. 2, a plant only 6 per cent
self-fertile, gave 9 self-fertile plants out of 19 with an average
percentage of 24 and a range extending to 52 per cent. Likewise
the F, from (A X E22) no. 4 showed an average fertility of 14.1
per cent and the F; an average of 18.5 per cent with the total
average quite like that of families derived from parents highly
fertile.

Offspring from F, plants, either highly or feebly self-fertile,
behave quite similarily and regress in marked manner toward the
average of the F, generation. The higher averages for individuals
or for lines of progeny occur without direct relation to the per-
centage fertility of the immediate parentage.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 381

TABLE 7
RECORD FOR SELF-POLLINATIONS OF THE CULTURES OF ‘IMPROVED RED-LEAVED TREVISO”’

Record for heads pollinated
Dates picks ev ie Seeds per head. Remarks
heads
1914 Series from No. 19 X No. 27 of 1913
Nos tale: 15 15 fo)
Dist a4 13 ig! fe)
Zl 43 12 re fo)
isle 18 18 fo)
5s 2 13 13 (0)
Only a 10 10 fo)
Gall = 8 8 O
Srl ts3 II eit fe)
Onlieed 13 13 fe)
LOR 3 9 9 te)
2 3 18 18 (6)
1915
Series R No. 1. Parentage, No. 1 X No. 2 of 1914
Nos i.) o2 13 13 fe)
Dalia 9 9 (0)
Ball) 3 8 8 oO
So) 2 10 10 fo)
Ox, 2 20 20 (o)
ita + 4 .e)
Sale 2 16 16 Ce)
Oe) 4 22 22 (0)
10m) 95 18 18 oO
moe) A 12 12 fe)
Series RNo. 4. Parentage, No. 8 X No. 6 of 1914
Nowa) 93 8 8 oO
Te 2 10 10 fo)
Ie he 3 14 14 (0)
iMzs|t ae 14 14 (o)
isha) 9023 14 14 (0)
TOw 1 63 15 15 Ce)
21.| 6 16 13 3 4, 5,8
22F ane 14 14 )
Series RNo. 5. Parentage, No. 8 X No. 2 of 1914
Nove a3 18 18 fo)
PS |LE ge 15 15 fo)
Bolle we 10 10 Co)
AP |e 18 18 (6)
Bele 43 8 8 fe)
(Oe 9 9 (0)
Viol OZ 13 13 (e)
Sin || 10 10 fo)
Ou\ee 15 15 (0)
Oe ewes! 21 21 fe)
DE |oe2 9 9 (0)
T2s|pe 9 9 fo)
TAy | ee 8 8 fo)
nye) 33 14 I4 (0)
163.92 5 5 Co)
17 ae 12 12 fo)
TA laws 14 14 fe)
20. I 6 6 (0)
21 I 16 16 fo)
22 2 12 12 (o)

382 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

In the study of the self-fertility of the F;, F., and F; generations,
comprising a total of 341 plants, controlled self-pollinations were
made on 3,140 flower heads, which involved a total of at least
55,000 individual flowers.

Self-sterility and self-fertility in the variety ‘improved red-leaved
Treviso.’’—It has already been stated in this paper that as far as
tested the plants of eleven cultivated varieties grown in 1913
were fully self-sterile. Several plants of the variety red-leaved
Treviso grown in that year were fasciated. Cross-fertilized seed
was obtained between two of these from which pedigreed progenies
have been grown for two generations with the special aim of
determining the hereditary behavior of the fasciation. The 49
plants thus grown were quite fully tested for self-fertility as shown
in the data compiled in TABLE 7.

The eleven sister plants grown in 1914 were completely self-
sterile. The smallest number of heads self-pollinated on any one
plant was 8 and the largest 18, but in no case was a single seed set.
Cross-pollinations between certain of these plants were successful,
giving seed for a crop in 1915, of which 38 plants were tested for
self-fertility. Only one of these plants showed any trace of self-
fertility and this plant (no. 21 of series 4, 1915) was but feebly
self-fertile, setting 4, 5, and 8 seeds, judged to contain embryos,
in 3 out of 16 heads manipulated. These data indicate that in this
variety self-sterility prevails, but that an occasional instance of
self-fertility may arise.

In respect to fasciation, leaf-shape, degree of red pigmentation,
and various other characters the plants of each generation showed
wide variation. In the F, generation a few plants were not fasci-
ated. They were all quite similar in general vigor, habit of
growth, and flower color, but otherwise there were such wide
variations that the race must be considered as decidedly impure.

These plants were derived by inbreeding within a single variety
and constitute the only intravarietal breeding that I have con-
ducted with chicory unless the one generation of progeny from
A XC is to be thus considered. In both cases, however, the
self-sterility is almost absolute and cross-sterility is high. Such
evidence raises the question whether cross-breeding between self-
sterile plants of strains and varieties that are not of close blood
relationship favors the development of compatibility according to

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 383

Darwin’s contention regarding fertility in general, or whether
inbreeding and self-fertilization of pure races or strains gives the
greater fertility as Burck argues. Neither Darwin nor Burck
considered in this connection the sort of sterility (from physio-
logical incompatibility) seen in chicory.

Self-stertlity in hybrids between a wild white-flowered plant and a
plant of the ‘“‘tmproved striped-leaf’’ variety—Further data on the
point just mentioned were gained from F, plants obtained by cross-
ing a white-flowered plant (A X C) no. r with a plant of the variety
known as the “improved striped-leaf.’’ The five plants of this
variety which were tested were fully self-sterile. The parent used
in this cross was one of the plants tested. The cross was originally

TABLE 8

DATA FOR SELF-POLLINATIONS OF F; PLANTS GROWN FROM A CROSS BETWEEN (A X C)
NO. I AND A PLANT OF THE VARIETY “IMPROVED STRIPED-LEAF”’

oo: 4 ris} | = Tiss Wt)
Ny Seer Wee 2s (eee hens)
MM co aOR 2 a es: )
ee Rose) ese matte 3 ZEN CAN re (0)
Bee ake 2 Tie | ene )
"ip Aas oa: 2 ain ae 2 12 )
1S 2 ee 2 2ee, |e alee fo)
Melee bir cree 2 Ly. ey fe)
** pS eee 2 we Te fo)
‘SO eerie: 2 II jaar | 9)
“ieee 3 10 LOR |e eno
°° ST Scene. I II II fe)
“SQN 3 Il II fe)
‘|? <2 Oa ae I Orn PaO fo)
2 eee 3 Earaih PLS lh erO
Be teen tise: I 12 "6,020
” (yds Ge cee 2 I4 14 Co)
“Ot Hh ee I 3 3 Oo | Series with (A X C) no. I as pollen-parent
*hy 28 Cian eee 2 8 8 O
i Me oo 3 WG || TKS) fo)
; Cee coi BONS Nits a ae oO

6. sheen SEE | LE |. 0
7) Se tome Peal tt os Wa as fo)
*s )a MO baee tera 2 Aa ie 04! (0)
SO A ee 2 eee 15 O
1) DS. eee 2 ve a a On|
Re tn « I Somita 5 O
Ee ee 2 SerWhl S 0)
, Fase ee I GL lsrnO fe)

384 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

made to test the inheritance of red coloration. The plant (A X C)
no. I, as were its parents A and C, was without any apparent
trace of red coloration in leaves and stems, while in the leaves and
stems of the ‘‘improved striped-leaf’’ plants there was a very
strong red coloration. Of the F; generation a total of 30 plants
tested proved to be completely self-sterile as is shown in TABLE 8.

These plants were all blue-flowered, but they showed almost
every conceivable variation in respect to the amount and distri-
bution of red coloration. As there were no self-fertile plants,
further generations were not grown. The complete self-sterility
of the plants of the generation grown is, however, an indication
that crossing between widely separated strains does not neces-
sarily give the development of self-fertility.

In the various self-pollinations that have been made, a total
of 631 plants have been tested for self-sterility; the number of
flower heads manipulated is about 4,100, and the number of flowers
concerned is hence about 74,000. The studies were at first quite
general for wild plants and for plants of eleven different cultivated
varieties whose pedigrees were not known. The later studies,
which embrace the greater number of plants, were made on plants
of pedigreed stock, as will appear from the foregoing data.

PHENOMENA OF PHYSIOLOGICAL INTER-INCOMPATIBILITY
AND COMPATIBILITY

During the experimental work of 1912 it became evident that
cross-fertility such as has been reported in TABLE 2 does not always
occur in Cichorium, and that not only is there self-sterility, but
also cross-sterility, quite as Correns (?12) afterward reported for
Cardamine.

Results of crosses involving A and various of its progeny.—Several
crosses attempted in 1912 between wild white-flowered plants
grown from seed of the plant A completely failed. On this
account opportunity was taken during the summer of 1913 to
test the behavior of certain sister plants when crossed among
themselves and with a parent plant. For this purpose 8 plants,
all white-flowered and derived from open-fertilized seed of the
plant A, were tested as fully as the conditions allowed. These
plants were in their second year of growth and had all proven to

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 385

be self-sterile in the experiments of the previous year, data for
The data for the crosses attempted
with these plants are given in TABLE 9.

which are given in TABLE I.

TABLE 9

DATA FOR CROSSES INVOLVING PLANT A AND VARIOUS OF ITS PROGENY DERIVED BY OPEN-

POLLINATION

no,
heads

Record for heads pollinated

Heads
| with no
seed

16)

WOOROUUN DAHON DWOODNWHOWU AHH W WW

HoH

NUGNN OONWOONHODOXFHROOHHNDOONOXHNOOHOOHRODOOOOBMN

Number of seeds per head

5s Sai 9
TOml isthe
Ts 9, LOFTOS Tt; nA 13; 13, 153 7

3 3) 3; 6, Il, II, I2, 13, 13, 14, i4, 15, 15,15

2,4, 6, 6, 6, 8, 8, 8, g, 10, II

5, II
Io

5, 14

iy,
By Spekl eke, Laakso se Aw Sy LO. mS

3) 45 5) 51 71 9

Io
6, 6
Oy Fs Tete Os bly BL

2, 3; 13
4,7
7) 7s 8, 8, Il, 12, 14, 15

10, I2
ie 2)
2s slay ie LO
O74 Lie D2 te
6,9

No one plant involved in these experiments proved to be either
fertile or sterile to all plants with which it was crossed. The

386 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

plant A as a seed parent was fertile to 4 and sterile to 3; as a
pollen parent it was fertile with 3 and sterile with 4. The plant A7
as a seed-parent was fertile with 2 and sterile with 3 of the sister
plants, and also sterile with the parent A; as a pollen-parent it
was sterile with 1, and fertile with 3 of the sister plants and also
fertile with A. The plant Az7 as a seed-parent was fertile to 4
sister plants and sterile to one and with the parent A; as a pollen-
parent it was sterile to one sister and to the parent A, which were
the only two cases attempted.

In most cases. the data are fully conclusive for positive or
negative results, but there were numerous instances of feeble
cross-fertility, giving results quite similar to the cases of feeble
self-fertility already reported. In some cases, as in the AS X A
combination, where only one head out of thirteen set seed, there
may have been an experimental error. The evidence is clear,
however, that cross-incompatibility exists among these plants
and that among those which are compatible varying degrees of
such a condition may exist.

TABLE 9g includes data on 16 reciprocal crosses; 7 pairs between
parent A with 1 of its offspring and 9 pairs between sister plants.
Nine of these gave similar results; 5 pairs were fertile and 4 pairs
were sterile. In 7 pairs, however, the reciprocals were different.
These cases are of special interest and are collected in TABLE I0.

The parent plant A was fertile to the pollen of A7, but the
reciprocal was sterile. When it appeared from the seed produced
that this was the condition, the pollinations of 47 were continued
until 30 heads of A7 were pollinated with pollen from plant A, but
not a single seed was produced. Pollen of plant A was effective
on plants C, £3,and E22 (see TABLE 2) and on plants Ag and A27
(TABLE 8); also the plant 47 produced seed abundantly to pollen
of Ag besides setting abundant seed to open pollination, so it is
clear that impotency was not involved and that the compatibility
is different for the reciprocals. The results in the case of Ag X
A27 and AS X A17 are quite decisive, although a smaller number
of heads were tested. In the other four cases the fertility of the
one reciprocal was low in that a small proportion of heads set
seed; here the fertility was of the grade quite comparable to the
frequent cases of feeble self-fertility already reported. It is,
however, to be recognized that as already stated such results may

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 387

TABLE to

RECIPROCAL CROSSES GIVING DIFFERENT RESULTS

AX AGUS aeons 2 Bint) Sis Bee Papo oO (o)
AG dScAn One ee rane 20 17 ) 8 I 10
A7 X A23 7 fe) II Se ergs
A8& X Al7 10 Ons Eye li ae te etal Beano a2 ace)
AS SoA eats as Cpa Ope GA) 3-66
A8&8 X A23 10 Oy | Grp e2 AwT;
Ag X A27 4 @ | I 5 A ie Sey Teles INS
ASEAN SHOT oof io Aomass 2 4e I Fama ie coe en a 7 12 1 || at)
GEC) non7

SG (An Xe) 70s Os. aaa LO 2 2,5 10 fe)
ASX ©) n0n5 |

SUC SO (Os le Seo 4 Tis fa 4 fe)
Ba x (BF) XK Aene3 3... 5 3 1s Hl iON
(B22 OA) 0M |

SUH >< Al) (a0) Shag I 3 5 ah bo
R 1914—no0. 6 X no. 8...| 6 of 3. i 6: 1G, 8) 10), TO, "UK. n2
R 1915, Ser. I— | |

OSGI DK FAL Gs ot Qt OD OE 5 (0 iM | Seelam = LOWS
RY TOW Stee, = |

NOs TOM Aerated: Sia I Ca ere CS, 2 O

involve in some instances an experimental error. There were
also cases such as the cross A X AS in which one reciprocal was
strongly fertile and the other very feebly fertile. Seven other
reciprocals, reported in detail in later tables, have given different
results and these cases are included here. In these, as a rule,
the fertile combination is only feebly fertile, and while the results
in some cases may be subject to some doubt there can be no doubt
from the data of TABLE 10 that reciprocals may actually give
different degrees of fertility even to the extent of one being highly
fertile and the other fully sterile.

Results of crosses between (A X C) plants and their parents.—
The artificial pollinations bearing on cross-incompatibility which
were conducted in 1914 and 1915 were directed to plants whose
immediate parents were both known. On account of the difficulty
of performing all possible combinations, no series has been fully
completed, but the data thus far obtained are given in the following
tables.

The data in TABLE 11 pertain to the crosses that were made with
the (A XC) plants. Six plants were used as seed-parents and

388 MEMOIRS OF THE NEW

TABLE 11

YORK BOTANICAL GARDEN

DATA FOR CROSS-POLLINATIONS INVOLVING PLANTS A, C, AND THEIR PROGENY

Seed parent

(A eC) nar Bac os |
(A XC) no. 2.....
(A X C) no ee
(A X C) no Beal
CA CLA: G8
‘¥ ee 2
(ER Cho 8
a.
Cy Tee

| (A

Pollen parent

<i) nOn2. ae
Sia
Bice
mt Cian
ee
THO)
MELONS Hoe eo
“a Riek
. Once
“ ches
- TOW
SCC) mote
oY Bee
7 Oe
<u) One
a ae
Aine
- One
4 Vite
“t Stak
a Qua
TOs
SG) ivona ree:
fe ee
_ rast
. ac he
5.
re One
e- Onn
TO...
aC WO wel
tt rene
= ace
7 Bie,
rH Ties
ae a
10..
TE) ey (1a gt eee
if Bec tee
# OF
o Saat
x.) 10:

iN
}O'S SN Ain vw tN

Dates

OOO Oe ee RR NN eRe ee OR RRR NR NDR DN RD RE

Record for heads pollinated

Total
no,
seeds

4
10
I2

se
LIMP UWU OUMNEUMWUN DON AN NUMWUNUW DUNT Of OUD

Heads
with no
seed

| on lon
DL ULUNWU ODUNFUMNO ON DH RH WWUW QUNT® OF COUNW

= UW oO

pos

oof

I 6
I +f
2 6
I 3
2 4
. 5
I a
2 10
I 4
I 2
2 8
2 6
2 1o |

NONOOO0OSO

Seeds per head

1/2

Zaye}

6,7

aan

IT, 12) 8) 5, bos

8
I

5, 12

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 389

all 10 were used as pollen-parents in a total of 50 combinations,
of which only 15 were fertile and these were all cases of feeble
fertility. There were 9 pairs of reciprocals; 5 were both sterile;
2 were fertile and 2 gave different results as already noted in
TABLE I0.

Four of the (A X C) plants were used as pollen-parents on A;
all were fertile to some degree. Nine were crossed with the
parent C; all but two were sterile. The four plants fertile to A
were sterile to C.

The cross-compatibility within this series measured by the
fertility of the crosses made was decidedly feeble, both in respect
to the series as a whole and in respect to the individual combina-
tions with perhaps the exception of the cross A X (A X C) no. 1.
No one plant, either as a seed- or a pollen-parent, was consistently
fertile or sterile to any considerable number of its sister plants.
There were no indications of impotency in any of these plants
and they all set considerable seed from open pollinations.

Results of crossing (A X E3) plants and their parents—The Fy
plants derived from crossing A and £3 were crossed among
themselves and with their parents to the extent reported in
TABLE 12. Of the (A X £3) plants four were used as seed-parents
with pollen of 9 sister plants in 17 combinations. Two were strongly
fertile, 1 was feebly fertile, and 13 were sterile. All 9 plants of
this series were sterile to the parent A. It may be noted that in
the two strongly fertile combinations the pollen-parent was no.
8, a plant which in self-pollination (TABLE 3) was feebly self-
fertile. This plant, however, was sterile as pollen-parent with the
parent A.

Two of the (£3 X A) plants were seed-parents in 14 combina-
tions involving sister plants. One cross was strongly fertile, I was
feebly fertile and 12 were sterile. Ten of the plants were tested
as pollen-parents with A; of these combinations 3 were sterile and
7 were fertile in some degree. Seven were tested as pollen-parents
with £3; 5 were fertile and 2 were sterile. Six were used as seed-
parents with the pollen of £3, and of these 2 combinations showed
feeble fertility.

Both series (A X £3) and (£3 X A) showed among themselves
on the whole a low degree of fertility, although 3 of the 5 indi-
vidual cases of fertile crosses were highly fertile. In respect to

390

TABLE 72

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

DATA FOR CROSS-POLLINATIONS INVOLVING PLANTS A, £3, AND THEIR PROGENY

Seed parent

(A) <9) Ores

(A X E3) no. 2...

(A x E3) n0.3...

(A x E3) no. 4...

Pollen parent

(A X E3) no.

(A X £3) no.

| “ce

(A X £3) no.

One
| (A X B3) no. 1..
Hi gee

i. ae

Fi Cun

ae vine

ae Ss.

ae Gow
(Cigar A))in0.-7. .
| ae Aik
ae 6*.

ae Tone

i Six
ae

TOs.

CEG UIGeAN) 702 2...
es

ae ae

i ‘oped

ae On

Me 10..

..| (3 X A) no. Tr...
| ! Fs
5 4°

ae bee

Oks
ina

TO.

Be Die

te fats

CON W'ON OR ooN AR HAA

Record for heads pollinated

Bee HH Ne HN RN} HH

Nw NNN NHN

OOO OS

Se ee ee Ne eR

‘Total

no.
heads

—

NNW DAWU DAN O HW Nf

Lal

UB Y Dw com oo

UUMUNKWUNwWL NHL NUWNDOL

NfoONL NK OUt+L

| Heads

with no
seed

SCUMNW AWM ODN ORWHNS

FUP N DH On D

OMNNWUNWE NDP NUD ALP

poof OWrR+LN

Heads
with
seed

NOONOCDOOMOOQOOCCOCOC 80

io)

eoooo0o0o0c0oo

mooodoooocoonond

=OWNONULON

Seeds per head

3, 3, 8, B, B

foal
N

4, 5, 5, 6, 9, 10, 12,
TS; LO; 16. cane

2,7

8, 15, 15, 15, 17

I, 4

6, 12, 15, 4
S16; 07. 5
2,7

10, 15

5, 12, 13

+- B
, 3B

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 391

TABLE 12—Continued

Record for heads pollinated
Seed parent Pollen parent | Total | Heads Heads
Dates no. withno} with Seeds per head
heads seed | seed
Ue aacene pt gers: 8 cp oh (Bye Ay no) T.: i 2 2 One.)
NE OS i 7; 22) 5 3 202 NG
. svelbbir 2a eere i 3. 2 8 5 5 Ut 405
ik tase «ghee hea ER Bee 3 5 2 2 B, BB
iy lod Oe eR ee ns OREN 2 4 2 2 8, B
tA caceaa tee ete es RS Toi faa? eat 5 I 4 |8,8,3+B,7+B
i i Tea I 5 5 (0)
CS eT ir ARG te ata ees ene 8 lap Oi Bre eae. lar O
‘ ae |
: 5 oe a a I 4 4 oO
% EI AIRE |g tie ota Ree PR OF I 4 3 Tae
Si Sopa | aor echelon ee Se I 3 S oy |
i Ogee een re cova I 4 3 I 2
a TOs: Nel Meee Sen te. I 4 4 (0)

* A self-fertile plant.

fertility as pollen-parent with their own parents, there was a
marked contrast; the (A X £3) plants were completely sterile
to A, while the (£3 X A) plants were highly fertile to A and also
to £3. On the other hand, of the 6 plants of (H3 X A) used as
seed-parents with pollen of £3, only 2 showed any degree of
fertility.

The table includes data on five pairs of reciprocals; of the
(A X £3) plants, no. 1 with no. 2, and no. 3 with no. 4 gave no
seed, of the (E3 X A) series, no. 5 with no. 7 were sterile, and the
pair (£3 X A) no. r with £3 were sterile; but (£3 X A) no.3 X E3
was sterile while its reciprocal was fertile.

There were II cases in TABLE 12 (indicated by *) in which pollen
from a self-fertile plant was used on the pistils of a self-sterile
plant; such pollen proved fertile in 8 combinations and sterile in 3.
The number of crosses is not great, but is evidence that the pollen
of self-fertile plants gives much the same sort of results in crossing
as pollen of self-sterile plants.

Results of cross-pollinations involving the (A X E22) hybrids.—
Of the (A X E22) series there has been opportunity to test I plant
(no. 10) as seed-parent with 21 of its sister plants. The data
given in table 13 shows that there was fertility in but 4 of these
crosses. Eleven were used as pollen-parents on A; of these 5
were sterile and of the 6 fertile crosses, I (no. 4) was highly fertile.

392 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

TABLE 13
DATA FOR CROSS-POLLINATIONS INVOLVING PLANTS A, E22, AND THEIR PROGENY

Record for heads pollinated

Sebd parent Pollen parent

(A\ XB22) nO. nO mA ex bee) no. 4*

N
™N

CW Um NUNWWL QAUKUNN DOLUHUD

Ts +0; 0,002, tt

2, 2, 4, 6, 6, 6, 7)
LO, Al, sl Dseteh nes
12, 13, 14, 15, B

to
ON AeA ee RRO Oe OR OR ee NOR OR OR NO Oe
N COlUIWE NUWWHE QDAUUUWN DW &N® UO)
NOW;/SOOCDOODOOODODOODOCOOHOOWONNO SO

I
_

5,7,8
3

—
N

ROW DOW NL

2; 4, SREP
I,7

3) 6, II, Il, 13
2NT6

10, 13, 14, 17, 18

mee OWE CON Of|OW HR HN

Beg. ccs suas tao |e). no, 2”
xbox eas eee 1 q*

_
nko SCHUM dnN OU UWW AL HOW WDOLULH

AER Ree ee eee )i90,. Z I
: + I
I

conuoonmoumnnconoonas

(E22 X A) no.1.. | (22 <A) no. 3

|
|
|

5
ae es ae 6
(E22 X A) no. 3..| (E22 X A) no. 1

ae < oe 2

esi a as

a ae

ae ae

wes U
ore!
=
~~

* Self-fertile plant.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 393

Of the 7 tested as pollen-parents with E22, 3 showed cross-
fertility. |

The plant (H22 X A) no. r was sterile with pollen of two sister
plants and feebly fertile to one; the plant (H22 X A) no. 3 was
sterile to pollen of 4 sister plants. The parent plant A was tested
with pollen of 5 of the (E22 X A) plants, with 4 of which it was
fertile.

As far as tested the hybrids of this series showed strong cross-
sterility, as out of 28 combinations only 5 were fertile. On the
other hand there was rather marked fertility when pollen of these
plants was used on the parent A.

Eleven of the crosses given in TABLE 13 involve pollen from a
self-fertile plant with a seed-parent that is self-sterile: 6 of these
crosses were fertile. The pollen of the self-fertile plant (A X
E22) no. 4 was sterile to the parent E22 and to a sister plant
(A X E22) no. ro, but was highly fertile to the parent A. These
results agree with those of TABLE 12 inshowing that the self-fertile
plants are not cross-fertile as pollen-parents with all of their
sister plants, and that when fertile there may be considerable
variation in the degree of fertility. These facts are suggestive
that cross-sterility from physiological incompatibility may exist
between plants of the same species that are self-fertile. The
difficulty of making emasculations or depollinations in chicory
necessary to controlled cross-pollination between self-fertile plants
had thus far deterred me from making this test.

A summary of the cases of back crosses given in TABLES 9, IT,
12, and 13 shows that plant A was crossed as a seed-parent with
46 of its progeny and that in 25 cases there was fertility. The
total of all back crosses of offspring on a known parent is 69, of
which 35 were fertile and 34 sterile. The number agrees more
closely than do the results of Correns with his theoretical ratio for
such a cross in Cardamine. The range of variation in the actual
fertility, however, is so great in both cases that the grouping of
all offspring into two classes with reference to cross-fertility with
a parent is of little significance, and in addition the results ob-
tained in the pedigreed self-fertile strains of chicory show that
the conception of line stuffs is untenable.

Results of cross-pollinations involving the variety “‘improved red-
leaved Treviso.’’—Data have already been presented (TABLE 7) for

394

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

TABLE 14
DATA FOR CROSS-POLLINATIONS INVOLVING THE VARIETY ‘‘RED-LEAVED TREVISO”’

Record for heads pollinated

Seed parent Pollen parent Total | Heads | Heads |
Dates no. | withno| with Seeds per head
eads seed seed
SS | Se | ——————— See
R. of TOLL 0O.: (IS R.OF W914 no: 925.). 65 19 | x1 8 5; 6;° 65.78 TOnetos
ibs The
a 1 Wale a3 Beet ee si ae oO
a 2, % , Leslie Al 8 5 2 Te 25006
yi Sin. * 1. | 22 15 15 ()
. Bk te PA ve 3 12 12 (0)
3, Gy. ts Te ee 6 6 (o)
P Ss ry ie. aL 2 Zz fe)
. ‘eter . ei! oo 2 fo) 2 Hee ANS
be Bie ay (Sse I 9 3 6 65/8; LO; 10; Ll,ete
‘ Os. A: TOES. OE EL II oO
4 TOs: ns Biel eal 9 9 (0)
* TOs . One| a 6 6 oO
ee Te Ss a Wes 12 12 (a)
R. 1915 R. 1915
Series Ino. I. series § no. 5..| 1 2 2 fo)
Wh eR IOs ee StL I 4 O 4 2 5ecO, sl} oe
eat Sete 12 Ne Pee Oo) (OE 3 2 I II
ca ea oe SS a aes lo al a 2 I 6
cae a wee 2S 2 er ee I 5 (0) 5 5) 7a Ost Sy Le:
byl! ween LO DY ace Beto lae I 5 oO 5 2, TA,0b) BS
ae 4 ae 17. f ae 5 ‘a 20. : I 4 4 (0)
ANN ae toe 0 Wer ees ed ¥ 9) oak 2 fo) 2 10, B
ae 5 ae tT. ae I ae I ns I a a O
Ch uSakee- ee wet at Seer) 2 7, 2 5 273, TA pa eS
CODY 6 LL a ie) eae ears ee era I I O
ingly 6 cata 4A PG een HO 5 (6) 5 1 gel a Wi Ba 2
ie eee ee a etait! Wes) a 3 I 2 10, 17
PAE, ‘: Ase * I _ eal eee 5 5 oO
- ee Ly ane) Ts 1, 3 3 oO
5 Bas 5 Te altel 2 2 oO
ee REM ee go ails oe ee 4 4 )
rao, GiteaveOne a ea See Bo lees oO
D9 Ch) ati. eae OL. 2 ai) oF ae Pe
ph SE ee Cahn oy dels pate a 5 3 2 Serene
ie prey BL a a: olor I 4 2 2 pth ale
“ce 5 “ae ee ae 5 ae 9. I 4 4 O
ae 5 ae 9. J ae I ae 10. si 2 5 | 5 oO
ae Piskia 115 3 ee pan tOs sh. 2 Be ao 5 1, 8; 9,300.72
ae 5 ae 9. : ae 5 ae 2. : I eB 3 fo)
‘Bp eee Neo oe: ee 3 2 I II
ae 5 ae Il oi ae 5 ae 6. . I a 2B ra)
Pee rcbjthaey oleae Gace ey ir od ar 2 3 0
mee gene Gn: 7h ASANO I 2 2 )
eS Sr meee gle eet ee 2 2 oO
ay. Bee a aly are) on ete ae aie Bele a I 10
ee eee Moe habe oe I Anal) +4 (9)
Nee ES Ss Al eee gee eee aes loa I 5 5 oO
Sa GERM Ur Berea a Art gia I I ) I II
Te Sy AEG 6 aaah sas Seren Vale I 4 4 (6)
OL SS Ale calc vt eee Ene eee I 2 oO 2 I2, 14
tT ST ne te Sm ect rae ei Ct I Bante Go 3 T, 6715
Rime Gee RN ie Os or EY Lae ay I Bomn|| Bae re)
‘er A TSS a ie ee I 4 3 Lira | ste
wt Dae sath Aa eterece vas emern ote 1 I 4 I 3 3,750
yee eS Series anos 15 ya) bd oe a eee 2 10, 13
m se NP Peden ay) So Peescary sen 27 i 2 oO

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 395

the self-pollinations of plants of this variety. In order to keep
the variety in pedigreed culture for a study of the heredity of
fasciation it was necessary to make numerous crosses to find fertile
combinations. In 1915 crosses were also made with the wild
white-flowered plant A which has figured prominently in the
studies already reported. These data are compiled in TABLE 14.

In 1914, 13 cross-pollinations were made, of which only 4 were
compatible. The work of this year involved 6 pairs of reciprocal
pollinations, four pairs (1 with 8), (3 with ro), (3 with 12), and
(9 with ro) were sterile, one pair (z with 2) were both fertile,
and one pair (6 with 8) gave different results as there was fertility
only when no. 8 was the seed-parent.

In 1915, thirty-two crosses were attempted between various of
the plants grown from the seed of the previous year. Fifteen of
these were fertile in some degree and in at least 6 crosses there was
rather high cross-fertility. No one plant was tested to a con-
siderable number of other plants either as a seed- or as a pollen-
parent.

The results with this variety have a special bearing on the
general question of the influence of close relationship to fertility.
Twenty-four of the crosses were with plants of series 5, 1915, as a
seed-parent. These plants were derived from the cross (8 X 2)
of the previous year. Of the 12 combinations with sister plants
as pollen-parents, 7 were sterile. Of 10 crosses with plants of
series I as pollen-parents, 7 were sterile. The 2 series had the
same grandparents but different immediate parentage. The
results of the crosses made show no marked differences between
crosses within a series or between different series.

It is also to be noted that plants of this variety were not all
fertile with pollen of the wild plant A as 3 of the 8 plants thus
crossed were unproductive of seed. Of two crosses with A as seed-
parent I was fertile. The two reciprocals that were made gave
different results, as especially noted in TABLE 10.

General summary of all cross-pollinations.—In TABLES 2, 9, I1,
12, 13, and 14, data are presented for crosses involving 125 different
plants. <A total of 274 different combinations was attempted, of
which 159 were sterile and 115 were fertile in some degree. Gen-
eral cross-fertility on the whole seems less pronounced than is
cross-sterility. TABLE 2 is not fully representative of the results

396 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

obtained in 1912, as there were several crosses attempted which
were sterile but of which no complete record was kept. In TABLE 9
the fertile combination exceed the sterile, being 26 to 17; in the
other tables, each of which relates to pedigreed stocks, the sterile
crosses exceed the fertile and agree in the general results for all
crosses.

The total number of reciprocals made is 47, of which 15 were
both fertile, 18 were both sterile, and 14 gave a different result.
The latter have already been summarized in TABLE I0.

The total number of flower heads concerned in the cross-pollina-
tion reported is 2,168, which involve about 40,000 individual
flowers.

The total number of heads upon which the results of controlled
self- and cross-pollinations were fully recorded is 6,261. All of
these pollinations were made by the writer with the exception of
the pollinations made by Mr. A. C. Fraser, who continued the
experiments during six weeks of the summer of 1914 while the
writer was absent from the New York Botanical Garden. In all
of the pollinations, excepting those made in 1912, the writer was
assisted by a second person. Mr. A. C. Fraser assisted in this
work during the season of 1913, and Mr. Charles Holste has
assisted during the seasons of 1914 and 1915. The writer wishes
to record here his appreciation of the assistance thus given.

GENERAL OR, POTENTIAL FERTILIFY IN Gnicon

As the chicory plants grow in my experimental plots and wild
about New York and especially at Madison, Wisconsin, where the
writer has seen them in considerable numbers, there is no obvious
suggestion of sterility of any sort. Neither is there such an
indication from the conditions in the fields grown for seed pro-
duction which the writer saw in 1914 in the grounds of the Dippe
Brothers at Quedlinburg and of Ernst Benary at Erfurt, Germany.
The gardeners in charge of chicory-growing for these firms had
no idea that sterility of any but the most accidental sort is present
in this species. All plants seem to set an abundance of seed.
In any package of commercial seed, however, from the writer’s
experience, there are many light-colored and shrunken seeds that
fail to germinate.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 397

There appear to be no definite statements in the literature of
any sterility in Cichorium Intybus. Fruwirth (’09) describes very
adequately the development of the flower parts in the processes
of opening and notes the adaptation for self- and cross-pollination.
He also records that he failed to obtain seed from branches that
he had enclosed for spontaneous self-pollination; in ten trials of
selfing he obtained no seed, but as the weather was rainy he does
not consider his tests conclusive. He suggests, in discussing
possible methods that may be used in hybridization, that if self-
pollinated flowers set no seed the act of castration might be
omitted in crossing and only precaution taken to prevent insects
from bringing pollen. It is this method that the writer has most
generally used in crossing onto a seed-parent known to be com-
pletely self-sterile. The F, generations grown from crosses in-
volving plants A, C, £3, and E22 and which are especially con-
cerned with this paper were from seed obtained by employing
the depollination method as described by Oliver (710).

OBSERVATIONS ON EFFICIENCY: OF OPEN-
POLLINATION

To test the efficiency of open-pollinations and to obtain evidence
on the efficacy of pollinations in successive days throughout the
season, observations were made in 1914 on the flowers of a large
main branch on each of two plants. Each morning with the
exception of Sundays and days of heavy rain the flowers in each
head on the branches selected were counted and a tag was placed
about the base of the head recording the date of blooming and
the number of flowers. Later the seeds were counted and the
number also recorded.

Data were thus taken on plant C from July 2 to August 24, 1914,
and these data are given in TABLE I5.

A total of 114 heads of plant C was observed (not including
seven heads which set seed but were completely shelled by birds),
comprising 2,304 flowers of which 1,402 set seed judged to contain
embryos. The percentage of flowers setting seed was 61. The
number of seed per head ranged from 0 to 21. In two instances
every flower in a head produced a seed. There were but five
heads that set no seed and these bloomed near the middle of the
season; three of these opened on the same day, July 14.

zg 6z 06 Sg S6 zg 06 Lg zg £S 0g og o9 Zg 18 Lg 0 18 SL 99 06 gL zl ES Of L 9 69 HE ch HS LS 9 SL|

626° sor £891 It gt ci PE er 1¢ Zh gh cS te 4S o xz zo $6 bL eg V1 L6- 09° 2 b1-vl- Li ve. AL ZI gi S1|

Seen ee ee ________ Ea

zZ gi gt 6€ 61 gf oz gi SS 16 6E 6S 0g og IF 1g Oz IF €g EI zg 64 Sgr Cg Sor vor zz gor Ev So I€I Iz Iz oz |"

paas ‘ou [eIO],

“SIOMOPY “OU [BJO TL

¢ Ht aif! Zit Li zz
Li tr
¢ oI
oI
6 }
LI oye fie /Are avis TOMO sale ale ID ie ite As, Oieee oi Oe cro) Tze "|
Gye yrit (oe (out HP Gr at Yo) Cr tI
OL Oe 21 Ol; SOle ac 0 cI 2
9 Cleat 0S 0 fe =
ee I hs
Tn 2s oy
Z
if)
QI er 61 VI gr vw 61 © OL Zr gn Cie Cie G, F Cron a
91 9 SB cI cI Z 3
6 tI | =
ZI =
QI out Ysith et ele ell Ol aye YZ (oy Ceara 61
SI , VI St) |
ee a ee ee ed ee ee ee
It Seon on Call AM ZI ol a eee
tI
Nees SP ee ne ee ee EEE EE ee es
ieiy fea LI
ee a ee ee I ee a ee a ee ee
CT gI
“Jj9[ We payworpal siaMoy ‘ON *aaoqe pareolpul sayep uo Suruado spvay 4107 paida][O9 spaas jo 1aquINN
“2 gt Lx St Gr sxx. ee g £ ig ¢ ¥ tf - Xo. 706 “6z be tz &z a i of gI ff: gt br €x It oO1 6 g 9 € z
isnsny Ainf |
J INVId JO SNOILVNITIOd-NAdO AOA VIVC

St ATAVL

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 399

Another plant, (C * £3) no. 6, was studied in the same manner
during the same summer. From the 6th of July till the 17th of
August a total of 121 heads on a single large branch was counted,
tagged, and left for open-pollinations. The results are tabulated
in TABLE 16.

TABLE 16
DATA FOR OPEN-POLLINATIONS OF PLANT (C X £3) no. 6

July i August
Ge 50 ro PO Se TA rs. 6. bites 18 20 Zee ez 23 24 27 20 30 ee 4 at
Number of seeds collected for heads opening on dates indicated above.
| 18 4 Oa HSN LG 5
Co)
Ce)
oO 3
(e) Ase 2
0 Oe
OF 2 Orc as
19 I Bey eAst LO wee: ce Cute Ss Soias 9
4
oO +
z O 3 6 3 Soo
o | 4. 0 (fie OR A ee obe Bie i5i 24
F 20 a WO ee “Ts Moll iG, MAO eG a Gh taney «ck
vo
0 3
3 5 4
= i 4
a 7 I ATES
3 ch 0 cee 6 4
A 9 6 Pee 24 BAGS 4 BRE S
ile a On sO Fay, SiO Ouse am LOL Oma | 7are ks 2 6
| 5
| 7
aes 0)
22 Vovay a Ole, & 0 6 6 3
23. | 10 2
3 |
CMC So. i fim ih sha Sa Ta ee One © Ch wee a =
24 II S
Oo
25 10
Total no. flowers..| 47 68 109 189 80 261 79 79 233 177 198 143 145 82 167 185 118 60 21 I9 21 | 2481
Total seed......+. 27 2A aye a IA aOe aT 68) AAM 73.032 (2A 226 BB AT OZR 8, 2s O 6 |. 637
My seed... .. 20+. 10 AS Bae amn She Se Se 927-1 12O.- -287. (22" 298 28 90, Bhim 20922) ofA7 29 26

The total number of flowers observed on this plant was 2,481;
the total number of seeds was 637, giving a seed percentage of 27.
There were 11 heads shelled by birds and which for this reason

400 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

are not included in the table. The highest number of seeds for a
single head was 12. There were 12 cases of no seeds per head;
10 of these were on July 14, the same date when 3 heads of plant C
(see TABLE 15) failed toset seed. The weather records taken at the
Garden show that on that date it was cloudy with some rain.
Evidently on this particular day the weather conditions were
unfavorable to insect pollination or to fertilization.

In comparison with plant C, the plant (C * E3) no. 6 exhibited
a low degree of fertility; the daily percentage of seeds set was
lower and the number of seeds per head was consistently less.
Such results may be due to a marked cross-incompatibility on the
part of plant (A X £3) no. 6 to a greater number of plants in its
vicinity. The fact that there were quite constantly few seeds per
head is, however, quite in line with the conditions encountered in
selfing and crossing. It is quite clear that the difference in the
total seed production of these two plants is not due to a difference
in flower number. Here the determination of flower number
enables one to compute accurately the percentage of seed produced
on the basis of the total that is possible.

The datain TABLES I4 and 15 are quite conclusive that heads on
any part of the plant at any time in the season are productive
of seed; a point that seemed equally evident from the writer’s
experience with the controlled pollinations.

From the data of TABLES 15 and 16, Dr. J. A. Harris has com-
puted the correlation of flower with seed number per head accord-
ing to the method he has reported (710). There is in both cases
a very slight negative correlation. This is so slight, however,
that it scarcely if at all affects the general results and con-
clusions, as it is clear that random pollinations at any time very
fairly represent the fertility of the combination, and that the
marked differences in fertility of self- and cross-pollinations are
entirely independent of differences in flower number.

While there was considerable fluctuation from day to day in
the percentage of seeds set to open-pollination, there were usually
in any one day some heads that were close to the maximum
number, especially if five or more heads were involved. In this
respect the plants C and (C X £3) no. 6 were quite uniform
throughout the season.

In the case of the controlled pollinations, pollen from known

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 401

sources was applied to all flowers of each head. In making com-
parisons between many such pollinations it is of importance to
know if flowers produced on different parts of a plant and at
different times in the season are relatively equally productive of
seed; the tests reported in TABLES 15 and 16 seem conclusive that
they are sufficiently so for a fair comparison and also that when
a low percentage of seed per head is set consistently there is a
real condition of partial physiological self- or cross-incompatibility
involved.

OTHER INVESTIGATIONS

Attention has been given to a study (a) of the requirements for
successful artificial germination of the pollen of Cichorium Intybus,
(b) of the facts regarding the germination of pollen and of the
relative rates of growth of the pollen tubes in self- and cross-
incompatibility as compared with self- and cross-compatibility,
and (c) of the more intricate cytological processes of fertilization
and embryo development.

The artificial germination of the pollen was a special subject of
investigation by Dr. Joseph C. Gilman under a scholarship grant
from the New York Botanical Garden in the summer of 1913.
A large number of experiments were made employing chiefly agar
plates and hanging drop methods of culture and using various
strengths of various chemical solutions and of the juices of chicory
plants. During 1915 in the studies made by the writer the pistils
with pollen in contact were placed on slides and kept in a moist
chamber for study. :

On plates of I per cent agar with 25 per cent and 30 per cent
sucrose a few tubes developed to a length two or three times the
diameter of the pollen, but as the greater number of such tubes
burst 1t is not certain that there was a real germination. Thus
far no method of securing artificial germinations more successful
than these has been discovered, and until much better germina-
tion can readily be secured there is no hope of determining by
germination studies whether pollen of different plants shows differ-
ences in their physiology.

Preliminary studies along the other lines indicated above have
been made and especially of the behavior of the pollen tubes in
the pistils relative to fertilization, but none of these have at present

writing reached the stage where they contribute any definite data
27

402 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

on the phenomena of physiological self- and cross-incompatibility.
To what degree the incompatibilities involve pollen-tube growth,
irregular fusions of gametes, or embryo abortion has not been
adequately determined.

DISCUSSION

There can be no doubt that in Cichorium Intybus the failure to
set seed in the numerous cases of self- and cross-pollinations is
due to some sort of physiological incompatibility operating in the
interactions between the cells concerned with the processes of
fertilization. Such sterility is to be sharply distinguished from
that involving different types of impotence or anatomical incom-
patibility as defined above. It appears also that the sterility
observed in chicory is quite the same as that exhibited by such
plants as Cardamine (Correns 712, °13), tobacco (East’ 15a),
Reseda (Darwin ’77, Compton ’12, 713), Eschscholtzia (Darwin
’77, Hildebrand ’68, ’69), and in cultivated varieties of the pear
(Waite ’95), plum (Backhouse ’11), apple (Lewis and Vincent ’09),
cherry (Gardner ’13), and in strains of the blueberry (Coville ’14,
715). Besides these cases which have been studied in some detail
there is evidence which indicates the operation of similar phe-
nomena in a considerable number of other species.

It seems that the causes of this sort of sterility are to be sought
in the physiological processes which are operating in an organism
quite independently of the anatomical differentiation of the sex
organs. Upon this broad generalization practically all students
of the subject are agreed. Many have been inclined to assume
also that in the higher plants the processes are concerned chiefly
with that phase of fertilization which involves the completion of
the growth of pollen tubes through the pistil to the eggs. In the
more specific analysis, however, of the conditions, processes and
causes, there is the widest diversity of opinion.

The more comprehensive of the theories, already discussed in
this paper in some detail, fall quite naturally into three main
classes as follows:

The view especially held by Darwin that ‘‘self-sterility”’
(physiological incompatibility), not including that in dimorphism
and trimorphism, is incidental and a result of the direct influence
of external environment, producing too great similarity in the
germ cells.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 403

2. The conception that the causes of this type of sterility are
purely individual and due solely to the fact that the two kinds of
sex organs are produced by a single individual irrespective of any
particular type of inherited nuclear or cell organization. Jost’s
conception of individual chemical stuffs that are similar in the sex
organs of an hermaphrodite individual, and Morgan’s view of
similarity in so-called protoplasmic association inhibiting gametic
union respectively. These conceptions emphasize internal en-
vironment.

3. The view that this sort of sterility is due to too great a simi-
larity of nuclear constitution as regards certain definite hereditary
units. (a) In a similarity involving the presence in the gametes
of an hereditary unit solely associated with the production of a
so-called line stuff: emphasis is placed on a particular germ plasm
constitution; the view held by Correns, Baur, and Compton.
(>) In the relative similarity of the male gametophyte only (in
respect to any one or more hereditary units of any sort) to the
hereditary complex of the sporophyte; East’s view.

These divergent views are, for the most part, due to the par-
ticular emphasis which the one or the other investigator has given
to certain phases of the phenomenon or to certain facts obtained in
their particular experiments. They all agree in making similarity
or lack of differentiation in sex organs responsible for the incom-
patibility.

Darwin considered that the constitution of sex elements may,
to a considerable degree, be influenced directly by changed condi-
tions of growth (theory of pangenesis). The persistent self-
sterility of strains of plants like Eschscholtzia he considers a direct
but rather incidental influence of external environment which
reduces the sex differentiation that usually gives fertility. He
attempted to distinguish this sort of influence from that which he
thought operates through inbreeding in which the degree of rela-
tionship, as he believed, also influences the degree of compatibility
of the sex elements. The cases of a markedly decreased fertility
seen in cross-bred but self-sterile plants did not agree with Darwin’s
view that crossing increases fertility, hence Darwin rather unduly
emphasized the fluctuating and sporadic nature of such sterility,
ascribing its causes also to change in environment.

My plants of chicory are grown under as nearly uniform con-

404 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

ditions as is possible under field treatment, but plants of the same
line of descent growing side by side show such wide and fluctuating
differences in the degree of their self-fertility that there seems to
be no direct connection between these phenomena and the im-
mediate conditions of growth. Yet it is entirely possible that
the history of the varieties under cultivation and the spread of
the species in new regions may have been, in quite the Darwinian
sense, factors in inducing the physiological conditions that are
associated with the present existence of self- and cross-sterility
and fertility in the species. Careful and extended methods of
pedigreed culture are necessary to enable one even to guess at the
actual causes contributing to the development of such characters,
especially in view of the possibility that they are epigenetic and
intercellular in nature and manifest a wide range of fluctuating
variability.

It is apparent, however, from the evidence accumulated since
Darwin’s time that the phenomena of self-sterility as seen especi-
ally in such cases as Eschscholtzia, Reseda, Cardamine, and Ci-
chorium are more than “‘incidental’’ as Darwin was inclined to
believe, and may have a special biological significance in explaining
the interrelations of living cells both in sex fusions and in vegeta-
tive growth, and the expression and heredity of such relations.

The conception of sterility as developed by Baur, Correns, and
Compton, is manifestly too simple. They claim that such char-
acteristics as fertility and sterility can be stated in terms of rela-
tively fixed and constant units of germ plasm, and attempt to
analyze the internal conditions involved in incompatibility on the
hypothesis that these conditions are predetermined by the physi-
cal transmission of definite line stuffs as hereditary units which
are directly responsible for certain specific and individual differ-
ences on the one hand and similarities on the other. The evidence
in chicory is quite clear on this point. As described above,
crosses between self-sterile plants gave an F,; generation of 172
plants of which 15 showed some degree of self-fertility. The
study of the progeny of these self-fertile plants as to sterility and
fertility in self-fertilized line cultures gave results which are
perfectly clear and definite. Both the F, and F; generations show
that self-sterility and self-fertility are neither dominant nor
recessive characters in any consistent sense, that the character of

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 405

self-fertility appears in different degrees of intensity in different
plants, and that there is very irregular and sporadic inheritance
both of the character as such and of the degree of its expression,
if the two can in any sense be separated. The character of self-
fertility (and that of cross-fertility as well) appears with different
degrees of intensity whether in offspring from crossed self-sterile
plants or from inbred self-fertile plants. That these differences
are in many cases real and not due to the accidents of experimental
conditions is, I believe, indicated by the results. The conclusion
is inevitable that the quality of self-fertility is different in intensity
in the various plants. That such differences are really expressive
of internal constitutional conditions places the expression of self-
fertility quite on the same basis with the fluctuating variations
observed in practically all characters which have been studied
quantitatively.

The studies of the heredity of self-fertility in chicory show
that plants most strongly self-fertile do not give offspring all of
which are self-fertile, even after two generations of pedigreed
culture. In other words, self-sterility, which is strongly in evi-
dence in the parent strains and in Cichorium in general, tends
strongly to reappear in spite of repeated selections of self-fertile
plants. Neither is there a direct correlation between the degree
of fertility exhibited by parents and their offspring.

It is very obvious that there can be no simple numerical ex-
pression descriptive of the hereditary behavior of fertility and
sterility in chicory and, as I have shown, a careful study of Correns’
data leads to the conclusion that his actual observations do not
support the conclusions indicated in his formulae. The rather
general statements of Lotsy (’13) regarding the F2 generation of
Baur’s hybrids between Antirrhinum molle and A. majus indicate
great variation in regard to self-sterility as in all other characters.
He states regarding the progeny of one of these, ‘Il y a des plantes
auto-stériles et des plantes auto-fertiles, de sorte que l’on peut
dire avec raison qu’il n’y a pas deux plantes identiques parmi les
255 individus obtenus en F,”’ (p. 420). In view of this fact, the
opinions of Baur can hardly be considered, while those of Compton
can not be seriously considered until the data are at hand. For
the explanation of the causes of self-sterility in chicory, I am
convinced that we must look most especially to the type or grade

406 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

of sex differentiation operating in the individual rather than to
racial or line characteristics or stuffs for the development of
conditions, local or quite general for the plant, which determine
its relative fertility.

This is fully realized by East, who states with reference to his
own experiments with tobacco already discussed in the intro-
duction, ‘‘When these experiments were begun, I expected to
find that the facts would accord with a simple dihybrid Mendelian
formula similar to that which Correns later proposed as an inter-
pretation of his results. Yet only by considerable stretching and
a vivid imagination will Correns’ data fit such a hypothesis, and
my own data do not fit at all” (’15a, p. 82). East’s interpretation,
although recognizing that there can be no hereditary factor
‘ directly representing fertility as such, assumes that the direct
conditioning substances are in the germ plasm. He considers that
the physiological relations are mainly those of pollen-tube growth,
involving interaction between the somatic cells of the pistils and
the pollen tubes, and the favorable reaction is assumed to occur
only when the haploid nuclei of the pollen tube possess at least
some one factor which is not present in the nuclei of the diploid
cells of the pistil. This relation, purely somatic at least on one
side, he calls ‘‘gametic incompatibility,’ a term which hardly
expresses the processes assumed to be involved.

It is especially to be noted that Darwin, Correns, and East
seek the causes of sterility in a lack of differentiation of the
gametes; it is too great a similarity that prohibits fertility. With
Correns’ no plant can be homozygous for any one line stuff:
with East xo plant should be self-fertile since its pollen grains can
possess no element of the germ plasm which is not found in the
somatic cells of the pistil of the plant on which the pollen grain is
formed. The narrow applicability of East’s theory is most evi-
dent. It ignores the facts which Burck has emphasized so strongly
and the abundant evidence, discussed later in this paper, that it
is similarity of germ plasm elements that favors fertility. Ac-
cording to East’s view self-fertility should not occur in any plant,
there should be no close approach to homozygosity such as he
has previously pointed out is the rule in tobacco, and there should
never be the development of self-fertile plants from self-sterile,
unless the hereditary units of the germ plasm are subject to

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 407

sudden and repeated changes in preparation for each self-fertiliza-
tion. Any further modification of this general view which should
assume that different grades or degrees of activity of single units
or groups of assumed hereditary units can account for the phe-
nomena of feeble fertility only makes more obscure the physio-
logical processes, and, would not in any case enable one to. predict
what the behavior will be in any species or strain.

East’s observed results are of special interest in showing that
even in interspecific hybrids the character of self-sterility may
appear in all (or nearly all) of the offspring among which there is
nearly complete cross-fertility. In his results cross-sterility is
almost entirely absent; in Correns’ results cross-sterility is strongly
in evidence as it is in chicory. These apparent discrepancies
emphasize the sporadic and fluctuating nature of self-sterility and
demand a theory which shall account for the relations of cross-
sterility and self-sterility as they appear in breeding.

It is evident that there is much in the phenomena of self-sterility
that favors the general basis of the conceptions of Jost and Morgan.
It is most obvious that self-incompatibility, as indicated by the
self-sterility of such hermaphrodite plants as Eschscholtzia, Carda-
mine, Reseda, Nicotiana, Beta, Cichorium, etc., and in such animals
as Ciona intestinalis, has appeared, when from the nature of the.
case, the reproductive organs and gametes are of the closest possible
physical relationship. In each individual they are produced by,
and in large measure composed of, somatic tissues with the same
hereditary complex, and when borne in the same flower with a
close cytoplasmic and sap relationship. The evidence seems clear
to Jost and Morgan that differences in the hereditary complex of
spores, gametophytes, and gametes are not essentially involved,
and that the causes of the incompatibility are to be sought in the
conditions developing from the close physical relationship of the
sex organs. In this sense the constitutional conditions present
may involve lack of some sort of constitutional (sex) differentiation
quite as Jost assumed. It appears that this condition also may
even give various grades of gametic incompatibility as in Ciona
intestinalis. This suggests that certain phases of fertilization are
to be considered as influenced by the close relationship of the
organs concerned. Whatever may be the affinities of the elements
of the germ plasm in the act of cell fusion, certain phases of the

408 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

processes of fertilization are no doubt conditioned by the physical
relationship of the sexual organs especially when there is differ-
entiation with respect to time of development.

A serious objection to the conceptions of Jost and Morgan is the
very obvious fact that close relationship of the sex organs is
equally present in all hermaphrodite plants, large numbers of
which are self-fertile. In fact, in a single strain of plants, as in
chicory, self-fertile and self-sterile individuals may exist. Further-
more, there may exist all degrees of cross-fertility and sterility
among these self-sterile plants. These facts, especially, make it
fully evident that there can be no general or very definite appli-
cation of the doctrine either of individual stuffs or of purely
individual cytoplasmic relations to the facts of relative sterility
and fertility. These conceptions do not adequately distinguish
self-fertile plants from self-sterile, and give no evident reason for
the development of one or the other type.

SPECIAL PHASES OF THE PHENOMENA OF STERILITY AND FERTILITY

Before attempting to pass judgment on the very suggestive
views already noted, or attempting to formulate any new con-
ceptions, the different phases of the phenomena of sterility and
fertility may be especially considered.

The relation of cross-incompatibility to self-incompatibility.—The
results I have obtained with chicory indicate that the physio-
logical processes involved in the self- and cross-incompatibility
seen in this species are fundamentally of the same general nature.

The results are quite the same in both cases. As far as tested
there seems to be a very general cross-sterility in those families
whose individuals are mostly self-sterile. This is seen in the results
with the (A X C) series and with the generations of the variety
red-leaved Treviso. As far as known, at least some degree of
physiological self-incompatibility always exists within a_species
or strain showing cross-incompatibility. Usually the ohnomenad— —
of self-incompatibility is much the more pronounced; in fact so
much so that the phenomenon of cross-incompatibility between
closely related plants of seed origin (not involving dimorphism,
etc.) was not believed to occur previous to Correns’ report in 1912.
Unless it can be shown that cross-incompatibility such as exists in
Cardamine and Cichorium can exist without any self-incom-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 409

patibility, it would appear that the former is secondary to the
latter and involves quite the same processes. That the two are
not completely correlated is evident: plants of chicory that are
self-sterile may or may not be mutually cross-sterile, and any two
plants may exhibit different behavior when crossed with another
sister plant, quite as Correns’ data show in Cardamine. Further-
more, self-fertile plants are found with degrees of fertility varying
from I to 70 per cent, which is quite analogous to the varying
intensities of cross-fertility. The evidence indicates that in these
cases cross-sterility is to some degree correlated with self-sterility.

The sporadic and fluctuating nature of sterility resulting from
physiological incompatibility—Darwin seems to have recognized
quite fully the fluctuating nature of this sort of self-sterility at
least in its appearance among different plants of the same race.
His data, however, do not reveal such wide variations with various
degrees of self-fertility as I have found in chicory. Correns’ data
show wide variations in the degrees of cross-fertility which, how-
ever, are ignored in his classification of results. Jost was fully
aware that plants only feebly self-fertile are frequent. In Ciona
different strains show different degrees of self-sterility. Neither
Darwin, Jost, nor Morgan was aware of the wide’ variations
that may appear in the degree of cross-fertility of self-sterile plants.

The behavior of sterility due to physiological incompatibility
in different species further emphasizes the fluctuating nature and
the marked individuality of the processes involved. Correns
from self-sterile parents obtained one class of self-sterile offspring
(though a few plants showed some indication of feeble self-fertility)
which exhibited all degrees of cross-sterility and cross-fertility
among themselves. East from self-sterile (2?) plants of two
different species of Nicotiana obtained only self-sterile offspring
which, as far as tested, showed almost complete cross-fertility.
In Cichorium Intybus, I obtained from self-sterile parents some
self-fertile plants having the most sporadic and variable ex-
pressions of self-fertility and exhibiting all grades of cross-fertility
among themselves. The difficulty of assuming that the causes
are identical in all these cases and due to the activity of any simple
chemical substances, either as to kind or intensity, is very evident.

That there are quite different grades and degrees even of com-
plete self-sterility is indicated by the fact that two self-sterile

410 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

plants may behave differently with a third self-sterile plant, one
combination being fertile and the other sterile. The grouping of
such interreactions was a point emphasized by Correns. The
wide fluctuations in his results, however, fully indicate that the
immediate causeJof self-incompatibility are strongly individual
and are operating in different degrees of intensity in different
plants. The group reactions, however, may be taken to indicate
a degree of similarity with respect to the actual processes operating
among certain plants. The results in chicory show that pollen of
plants that are self-fertile may not be effective on other plants,
and that reciprocal crosses may give different results, which is
further evidence of the wide fluctuations in the interrelations
involved in fertilization.

It is furthermore strongly indicated that the processes are
fluctuating in a single plant. This is seen in Jost’s assumption
that the qualitative nature of the “individual stuff’ is often
different in different parts of the same plant, and in Correns’
suggestion that a mosaic distribution of his assumed ‘“‘line stuffs”’
might be involved in such irregular results as he obtained. In
chicory, feeble fertility is exhibited by the development of a low
percentage of seed in comparison with the total number of flowers
pollinated. There is no evidence that in the ovaries setting seed
the processes of fertilization are identical with those in the cases
of most successful cross-fertilization. The need here of carefully
testing the relative vigor and fertility of individuals from seed
so produced is obvious and experiments of this sort are in progress.
Whether a low or a high percentage of seed is set, the processes in
respect to each single fertilization involve no apparent incom-
patibility, or at least the incompatibility is not sufficiently strong
to check fertilization. It should not be assumed, however, that
seed-setting in and between different plants indicates an identical
grade of compatibility. Self- or cross-fertilization that is of a
weak grade of fertilization may be associated with the develop-
ment of such weak or poorly developed plants and strains as do
frequently appear in any sort of breeding. Ina head of eighteen or
twenty flowers, all were pollinated with the same mixture of
pollen (in self-fertilization pollen of these flowers and pollen of the
flowers of another head taken from the same plant and usually
from the same main branch), but varying numbers of seed from

STOUT: POLLINATIONS IN CICHORIUM INTYBUS A4ITI

one to the full complement may be produced. Cases of persistent
low-fertility occur under the same conditions of chance experi-
mental error. In such cases few seeds are set in a head of similar
flowers all equally potent, and all seemingly subject to as nearly
equal conditions of nourishment as is possible. The differences
in compatibility exhibited by different flowers of the same head
to mixtures of the same pollen are identically the same in the
results (seed or no seed) as that seen in all the flowers in a head in
the case of complete self- or cross-sterility as compared with
marked high self- or cross-fertility. The differences can not be
due to lack of pollination, as the method used, especially in self-
pollinations, was equally ample for the distribution of pollen on
all stigmas. These considerations seem to indicate that modifica-
tions of the same processes that produce complete self-sterility
are also operating in the production of feeble self-fertility.

Further evidence of the fluctuating and individual nature of the
processes and conditions involved in such cases may be gained
by comparing the results of geitonogamy with those obtained
by autogamy. The earlier experiments of Darwin (’77), Ulrich
(702), and Jost (’07) indicate that geitonogamy may in some
cases be more productive of seed than autogamy. ‘This ques-
tion has never been adequately investigated in cases of physi-
ological incompatibility where every sort of morphological in-
compatibility is eliminated. The results of Shaw (’16), indicate
that in the proterandrous sugar beet autogamous fertilization
is very nearly always sterile, while geitonogamous crossing is
often successful, especially if the flowers are from distant branches.
In these self-pollinations care was taken to preserve the pollen
of the proterandrous flowers for use at the time when the stigmas
were receptive, but it was not shown, however, that pollen of the
same age was more effective in geitonogamy.

On the other hand, the marked persistence of self-sterility in
varieties propagated vegetatively as seen in such plants as the pear,
apple, plum, cherry, and blueberry is suggestive that the processes
are quite uniform not only in the parts of a single plant but in the
series of plants vegetatively derived from it. In such plants
there is especial opportunity to test the degrees of bud variation
and the relative fertility of plants of different lines of descent,
and thus obtain accurate data on this important point. Thus
far Such studies have not been made.

412 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The relation of incompatibilities giving sterility to cell organiza-
tion.—The particular types of cell organization which Correns
and East assume to be involved in the cause of sterility have
already been quite fully discussed. Quite a different view of the
influence of cell organization may be considered and from at least
two aspects. A particular type of somatic idioplasmic consti-
tution may be associated with the development of self-sterility
in respect to the role of the nucleus, as a part of the whole, in the
nucleo-cytoplasmic relationships determining the activities of cells
and their intercellular relations in the individual organ or plant.
A particular type of diploid nucleus may also be of significance in
sterility through its influence on the differentiation of sex organs
and of the gametes whose nuclei arise from them. In respect to
these points it is to be noted, as East has emphasized in respect to
the relations of the sporophytic style and gametophytic pollen
tube, that the causes of sterility from physiological incompati-
bility are operating in a plant itself largely independent of such
differences in the particular idioplasmic constitution of the sex
organs as may result from reduction divisions.

Perhaps a better assumption which would provide for the
sporadic occurrence of the differences which must be assumed to
be responsible for self-sterility in the case of self-fertile offspring
from self-sterile parents or, vice versa, of self-sterile offspring from
self-fertile plants, in which latter process all self-sterility doubtless
originated, is that of new or differentiated cell organization re-
sulting from such processes as Swingle (?13) has called zygotaxis.
This is especially an emphasis of a new differentiated condition
which may arise in the cytoplasm directly as a result of the rela-
tive distribution and position of the chromosomes in the nucleus.
We must recognize a large amount of evidence that chromosomes
have a fixed position in the nucleus as Boveri has so clearly shown
in Ascaris. But sporadic changes in the arrangement of chromo-
somes such as are assumed in the hypothesis of zygotaxis may
well occur in nuclei where the number of chromosomes is larger,
and thus provide for new cytoplasmic conditions of the sort
which may be assumed to account for the phenomena of self-
sterility.

In TABLE 3, data are given for 58 plants of the cross A X £22:
in these F; hybrids, from parents which differed widely, the reduc-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 413

tion divisions undoubtedly gave in each plant many kinds of
pollen with respect to the actual qualitative values of the germ
plasm (irrespective of whether or not there may be purity of
segregation). Fifty-three of these plants were fully self-sterile;
all kinds of pollen produced by each plant were ineffective in self-
fertilization, though in respect to segregation the pollen of these
plants must, it would seem, be as markedly different as that
from the five sister plants that were, however, self-fertile in some
degree. In the F, and F3 generations, self-fertile and self-sterile
plants appeared quite independently of the individual hereditary
complex, so far as it could be judged by visible characters. The
class of white-flowered segregates of the F3, which were very
uniform in appearance for each line, included both self-sterile
and self-fertile plants. Likewise, the members of F3 progenies
grown from blue-flowered parents were self-sterile or self-fertile
without respect to flower color or other characters. These results
are quite the same as those obtained by Correns, East, and Morgan,
which indicates that complete self-sterility may operate in indi-
viduals that are highly ‘‘heterozygous,’’ and that in such cases
the processes prohibiting self-fertility are operating on the pollen
tubes or gametes from pollen of that plant irrespective of their
idioplasmic differences, so far as the latter can be judged by visible
characters. In cross-fertility or -sterility quite similar behavior is
seen. It is on such evidence that the views of Jost and Morgan,
that the processes are purely somatic and intercellular in the
individual itself, are based and if self-sterility were universal in
hermaphrodites this would be a very natural conclusion.

The marked persistence of self-sterility in varieties propagated
vegetatively, already considered in the cases of the apple, plum,
pear, cherry, and blueberry, is suggestive that the conditions
giving self-sterility are perpetuated by bud propagation without
any marked change due to growth under somewhat changed con-
ditions. Carefully conducted experiments with such plants are
greatly to be desired to determine whether wide variations can
occur in the plants of the same clone irrespective of, or in associa-
tion with, evidences of somatic variation in nuclear organization.
If we may judge by the seed progeny of the cultivated varieties
just mentioned, the evidence is quite clear that they are vegetative
types that propagate fairly true vegetatively and maintain a type

414 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

of plant quite different from that which the great majority of the
seed would give. Such varieties are to be regarded as “‘hetero-
zygous’’—at least the diploid organization of the somatic cells
must be considered as far from ‘‘homozygous.’’ The evidence
here is therefore in favor of the existence of self-sterility in plants
that are heterozygous and whose gametes possess a marked
dissimilarity. |

It must be noted, however, that plants that are apparently
equally heterozygous may be either self-fertile or self-sterile.
Fifteen plants of the total of 172 plants of the F, generation re-
ported in TABLE 3 were self-fertile. It would seem that there is no
evidence of a difference in the degree of heterozygosity between
these and their self-sterile sister plants.

There is also evidence which seems to indicate that self-sterility
may exist in plants that are less heterozygous than the F; hybrids
just mentioned. In the inbred strain of the red-leaved Treviso
variety of chicory, all plants thus far grown were self-sterile with
one exception: the families. of this strain have, however, showed
wide variations in fasciation, in leaf-shape, and in the amount
of anthocyanin developed, and are hence far froma pure race or the
characters are showing sporadic variations of the eversporting type.
Selection of self-fertile strains derived from the hybrid plants
resulted in the segregation of certain F; progenies that were very
uniform in general appearance and in flower color, and were
decidedly uniform in all their characters; in these plants, appar-
ently the most homozygous of any of my chicory cultures, self-
fertility and self-sterility appeared with quite the same fluctuations
as in the F, generation. We must conclude that complete or
partial self-sterility and high self-fertility seem to occur without
any direct or immediate relation to those degrees of homozygosity
or heterozygosity that have thus far developed in the cross breeding
and inbreeding of these plants. It is such fluctuations as these,
however, that may be masking the real relations of sterility and
fertility to particular types of cell organization or differentiation.

It is clear that there is no decrease in respect to the self-fertility
of strains produced by self-fertilization. The average fertility
was quite the same for the F; as for the F., and in individual
records two plants of the F; gave a percentage fertility of 70 and 56
against the highest percentage of 52 for any F, plant. The pro-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS AI5

geny of F, plants of feeble fertility gave an average fertility that
showed marked regression to the mean fertility of all self-fertile
plants. In these generations, considered as a whole, there was no
apparent decrease of fertility due to self-fertilization. The results
are quite in line with the exceptional cases of highly self-fertile
strains which Darwin discovered in Ipomoea and Mimulus, and
which were considered by Darwin as noteworthy exceptions to
the general rule that inbreeding decreases fertility.

Thus far I have not been fully successful in isolating a race
solely composed of self-fertile plants. As only two generations of
self-fertile progeny have been grown there is the possibility that
such races will be isolated. The data obtained indicate clearly
that there is no decrease in fertility with increased homozygosity
and self-fertilization. This fact suggests that a marked degree of
similarity or homozygosity is at least not unfavorable to the
development and perpetuation of self-fertility.

Further evidence on this point is to be had from the ancestry
of the first self-fertile plants. With the exception of the one
plant feebly self-fertile reported in TABLE 7, all the self-fertile
plants derived from self-sterile parents are recorded in TABLE 3.
Of these (15 in number) all but one are progeny of plants rather
distantly related. However, all my Fy, generation excepting 8
plants of the A X C cross were from crosses of rather widely separ-
ated types, hence the results of close crosses between self-sterile
plants has not been very fully tested except in the red-leaved
Treviso variety, and even here there is evidently much varia-
bility. A large majority of the sister plants were self-sterile;
and wide crosses did not always give some self-fertile plants, as
is seen in the case of the 17 plants from A with £3, and the 30
plants of series 14 (TABLE 3). In respect to the production of
self-fertile plants, therefore, no general rule can be made that
does not have exceptions. The judgment of cell organization on
the basis of the expressed characters of parents, of sister plants,
and of offspring may, as is generally recognized in many cases, be
quite misleading.

The range and scope of cross-compatibility and -incompatibility
has a bearing on the question of the relation of sterility to cell
organization. Cross-pollinations between widely different and
unrelated stocks do not always produce seed. The few crosses

416 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

made between plants A and C and plants of the E series were
fertile, but not all wide crosses are successful, as the use of pollen
from plant A on various plants of the variety red-leaved Treviso
shows. Also it should be noted that the cross-fertility of closely
related plants as A and C (TABLE 2), A and Ag, A and A27 (TABLE 9)
may be quite as great as that between two more widely unrelated
plants as A and E22. The data for crosses within lines of known
descent given in TABLES II-I14 seem to indicate that there are a
large number of failures compared with those of crosses between
widely unrelated stocks. Individual cases of high fertility occur
quite the same in both, all of which emphasize the wide variations
of the processes involved in incompatibility.

The occurrence of cross-sterility and cross-fertility between
plants of different races or strains of chicory supports the view
that such plants develop similar conditions in this respect in-
dependently of their possession of the germ cell elements that may
be present. These facts emphasize that the conditions deter-
mining self-sterility or cross-fertility are in a high degree individual
rather than purely related to racial differences, and suggest that
the type of cell organization in any particular organ ( the style)
may be highly individual and relatively duplicated in widely
different races on the hypothesis of zygotaxis. These considera-
tions make it evident that the role of the particular content of
the idioplasm in respect to the development of compatibilities
and incompatibilities in fertilization is secondary to this more
general cell organization that is affected by differentiation of sex
organs.

Relation of vegetative vigor and fertility to inbreeding and cross-
breeding.—Closely associated with the foregoing topic is the
question of the influence of inbreeding and cross-breeding on
vegetative vigor and on the degree of fertility or sterility (of all
sorts).

Darwin sought to establish the law that ‘‘nature abhors self-
fertilization’? and that cross-fertilization increases vigor and
fertility while self-fertilization decreases vigor and _ fertility.
This Darwin assumed to result because of increased dissimilarity
through crossing as contrasted with decreased dissimilarity through
selfing of sexual elements respectively. Darwin approached the
whole question of cross- and self-fertilization from the standpoint of

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 417

the search for the source of variations which might be the material
for selective processes of evolution and the obvious fact that
crossing as contrasted with selfing was considered to lead to greater
variability made him the more willing to emphasize any evidence
that the former process is beneficial in itself even independently
of its relation to the increase of variability.

It is always to be remembered that even though self-fertilization
is productive of more numerous and vigorous offspring, the
increased variability resulting from crossing might make the latter
a vastly more significant process from the standpoint of evolu-
tionary progress. A study of Darwin’s data shows clearly that
the evil effects of self-fertilization in plants are not sufficiently in
evidence to establish the point. In fact in the two cases (Ipomoea
and Mimulus) continued longest in self-fertilization (ten genera-
tions) strains highly self-fertile and vigorous were maintained.
Darwin- fully admits not only that the supposed evil effects of
inbreeding are scarcely apparent, but that ‘‘it is difficult to avoid
the suspicion that self-fertilization is in some respects advanta-
geous”’ (’?77, p. 352). Darwin’s whole contention on this point
rests on the comparative increase in vigor and fertility which ap-
peared in certain cases of crossing. Here, however, the results
are far from consistent and convincing. Nearly half the cases
considered show no such benefit. This was realized by Darwin
who interpreted such negative results as due to the similarity of
the crossed plants because of ‘‘having been self-fertilized and culti-
vated under nearly uniform conditions for several generations”’
(C1 p.2eb

It is not always clear just what type of sterility is involved in
Darwin's results. It is not fully evident that such differences as
did appear between self-fed and cross-fed stocks are due to impo-
tence as I have used the term. Darwin seems to ascribe cases of
lower fertility in selfing to a combination of a weakened condition
(a type of impotence) and a lack of differentiation in sex elements
(a physiological incompatibility), which, however, he is careful
to distinguish, as to its immediate cause at least, from complete
self-sterility or, as I am calling it, well-developed self-incompati-
bility. At least in two genera, Eschscholtzia and Reseda, Darwin’s
data involve sterility due to physiological incompatibility. It is
most significant that when self-fertility does occur in Eschscholtzia

418 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the resulting plants, as described by Darwin, were more vigorous
than those of cross-bred origin. That they were less self-fertile
than cross-fertile, however, is apparently in no way connected
with their vigor.

The cases of plants reported by Darwin that were feebly self-
fertile but strongly cross-fertile suggest quite strongly that he
may have been dealing with the same phenomenon of incom-
patibility that is frequent in the case of the self-sterility which
he observed in Reseda and Eschscholtzia. A more extended study
of these plants in pedigreed cultures might have convinced Darwin
of this point.

The opposite view from that of Darwin on this particular ques-
tion has been expressed by Burck (’08) who has very fully sum-
marized Darwin’s results, and much available data in connection
with his own observations on various cleistogamous species.
Burck especially points out that (1) plants that are regularly
self-fertilized show no benefits from crossing, (2) that nowhere in
wild species is there evidence of an injurious effect from self-
fertilization, and that there is abundant evidence of continued
vigor and high fertility resulting from long continued self-
fertilization, and (3) that the advantage derived from crossing
within or between garden varieties appears when there is doubtful
purity, and is due to the fact that both vigor and fertility have
already been decreased by hybridization, and that when crosses
do give increased vigor and fertility the cross has restored in
increased measure the original nuclear organization of the parent
species.

Especial emphasis is given to the fact that Darwin worked with
so-called impure varieties and that when continued self-fertiliza-
tion resulted in a purer strain, as in the cases of Ipomoea and
Mimulus greater fertility and vigor appeared from self-fertilization
than resulted from cross-fertilization. Burck points out, as Dar-
win realized, that these facts are not in harmony with Darwin's
general contention regarding the injurious effects of self-fertiliza-
tion.

Burck considers that sexual affinity depends more upon simi-
larity than dissimilarity; the degree of fertility depends upon the
degree of harmony in respect to the total number of ‘“anlagen”’
borne in the nuclei. The facts, Burck contends, support the view

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 419

that full fertility is attained in self-fertilization between plants of
strains that are most pure.

It must be noted that Burck does not further identify the type
of sterility which he considers develops in cultivated varieties as a
result of crossing. It is conceived to be due essentially to dis-
similarity of gametes, although there may be, as it appears, also a
decreased vigor. The question whether it may assume such
marked types of self- (and cross?) incompatibilities as are seen in
Eschscholizia, Reseda, etc., is not considered. In fact this type of
sterility was not discussed. Proper experimentation in such cases
should show whether such sterility is in evidence. It is clear,
however, that Burck is not considering a type of extreme impo-
tence.

In marked opposition to the views of Burck and in general
agreement with the conceptions of Darwin is the doctrine empha-
sized by Shull and more especially by East and Hayes (’12), that
heterozygosity gives an increase of both vigor and fertility in
proportion to the number of “heterozygous factors in the organ-
ism” and that inbreeding although “not injurious in itself” (2433)
‘tends to isolate homozygous strains which lack the physiological
vigor due to heterozygosity”’ (p. 37).

The results of East and Hayes (12) appear in two types of
experiments; (a) those involving chiefly interspecific and inter-
varietal crosses in tobacco, which is usually highly vigorous and
fertile in continued normal self-fertilization, and (b) those involving
intervarietal crosses in corn, which is normally cross-fertilized
because of the marked proterandry that exists.

In the interspecific crosses in tobacco 42 crosses were attempted
(East and Hayes, ’12, table 5): 9 of these failed to produce viable
seed (the parent species were cross-incompatible) ; of the 33 differ-
ent hybrid progenies grown, 14 showed decreased vigor, 2 were
equal to parent species, and 17 were of increased vigor. It appears
from the discussion that the percentage growth of hybrids, as
given in the table just summarized, is based on the average of the
parent species. Of the 14 hybrid progenies with decreased vigor
one is reported as fertile and 2 as slightly fertile; of the 17 showing
increased vigor 8 were fertile, 3 slightly fertile and 8 sterile.
There was increased vigor in only 17 cases, but there is no apparent
reason why, if it is simply heterozygosity that increases vigor,
more of the combinations should not show increased vigor.

420 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

The low fertility (only 9 were classed as fertile and 5 as partly
fertile) of the series is noticeable and clearly shows that the ten-
dency of heterozygosity of imterspecific rank is to give sterility.
Evidently the sterility is largely of the type I am classing as
impotence, although this is not certain, for at least one case
(Nicotiana Forgetiana X N. alata grandiflora) here reported fertile
is later (East ?15a) reported as self-sterile (physiological incom-
patibility) but cross-fertile. Eight of the cases classed as fertile
are among hybrids that have increased vigor.

The evidence certainly fails to establish the point in question.
One can claim equally well that in the cases of increased vigor
and especially for those that are also fertile the results are due to a
similarity in respect to the cell organization of parent species
which admits of successful combination.

With the intervarietal crossing in tobacco the results are quite
as fluctuating and variable as are those of Darwin, and here the
writers are inclined to consider, as Darwin did, that when such
intervarietal crosses show no increased vigor it is not because of
simple relationship but because of similarity of gametic consti-
tution. As Burck has pointed out, the general application of
such a conception is untenable, and East and Hayes’s results in
tobacco are fully as unconvincing as are the results reported by
Darwin.

The most striking results were obtained in corn, in which as a
rule crossing between varieties increases both vigor and seed
production over that of inbred and self-fertilized stock. At first
glance the data seem most convincing and had such results been
obtained in tobacco the case would seem well established. How-
ever, it must be remembered that many races of corn are difficult
to self-fertilize on account of proterandry. Even with this
difficulty East and Hayes found that ‘“‘decrease in vigor lessened
with inbreeding”’ and that ‘‘good and bad strains were isolated”
(p. 22). Pedigreed line cultures, inbred, showed that no two
gave the same results; one strain of Leaming dent remained
vigorous and highly productive while another became nearly
sterile. Strains apparently similar in homozygosity show widest
variation indicative of spontaneous variation in natural vigor,
which is suggestive that in such highly cultivated varieties as
corn extreme sporadic variations may be constantly occurring, a

STOUT: POLLINATIONS IN CICHORIUM INTYBUS A2TI

condition which is well shown by the numerous and well-known
results of the so-called ear-to-row tests.

Further breeding work has shown that there are exceptions to
the general rule that crossing between varieties of corn gives an
F, with greater vigor than that of ezther parent and further that
the yield may even be less than that of either parent (Hayes, 714,
p. 364). Collins (14) points out that in corn ‘‘some crosses give
favorable results and others give little or no increase over the
yield of parents’”’ (p. 91), and that there is a decidedly ‘‘abnormal
behavior of self-pollinated maize plants’’ with also wide individual
diversity in the yield of hybrids which make the satisfactory com-
parison of the yield of parents and hybrids difficult.

It must be recognized that it has not been fully shown that in
corn the cross-pollination of plants of a good strain in such a manner
as to eliminate the effects of proterandry does not continue the
strain in inbreeding with high vigor and production. The condi-
tions in corn hardly make the tests as adequate as in tobacco,
but, considering all the data at their full value with proper con-
sideration of the limiting conditions, the results, as pointed out
by Burck for Darwin’s data, can be interpreted as not at all in-
consistent with the view that the best development and fertility
is associated with greatest similarity.

The emphasis that East and Hayes place on nuclear organization
in respect to presence or absence, or the presence of heterozygous
allelomorphs of assumed hereditary units is based largely on the
older conceptions that such units adequately represent characters
and segregate with purity in sporogenesis; both conceptions are
known not to be laws as these authors evidently realize (?11, p. 42).
The marked increase in vigor which hybrids often show, especially
when there is also fertility, may very well involve elements of
similarity that pertain to a type of cell organization and sex
differentiation that is far more fundamental than differences or
similarities in purely nuclear organization such as may exist be-
tween varieties of the same species and such crosses may very
well restore in increased degree a type of ancestral cell organization
in much the manner that Burck has emphasized.

The evidence obtained in animal-breeding, in which inbreeding |
of pedigreed lines of descent is the nearest possible approach to
self-fertilization of nearly homozygous plants, has been variously

422 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ©

interpreted. Some have emphasized the fact that weak strains
do thus arise, which is interpreted as evidence that inbreeding
always results through its own influence in decreased vigor and
fertility (see discussion and conclusion of Kraemer, 714). The
very frequent cases of highly vigorous and fertile inbred strains
or of intensive line-bred strains (Wilsdorf, ’?12), however, compel
one to attribute the appearance of weakened inbred strains to
causes other than inbreeding itself.

The results of experimental work with rats by King (’16) show
that inbreeding of pedigreed lines of albino rats for 22 generations
involving a total of 10,000 individuals has not led to any decrease
in constitutional vigor, but that there has been instead an increase
of body weight and fertility over that of stock albino rats. In
these experiments selectionsfor size and fertility were quite second-
ary and incidental. Such results indicate that inbreeding is not
of itself to be considered as injurious.

Relation of sterility from physiological incompatibility to vegetative
vigor and production of sex organs.—The physiological incom-
patibility involved in the sterility exhibited in chicory is quite
independent of any decrease in vegetative vigor, and it does
not involve in any degree the number of flowers produced. AI-
though the size of the plants and the relative number of flower
heads varied considerably, there is no correlation between the
number of flowers produced and the number of seed set either in
self- or in cross-sterility or fertility, and in all cases the actual
fertility bears no apparent relation to the potential fertility. It
was estimated that during the summer of 1915 the self-sterile
plant A produced at least 1,000 flower heads, the self-sterile
plant C about 2,000, the self-fertile plant (H22 * A) no. ro about
2,200, and the various self-sterile plants of the red-leaved Treviso
variety about 2,500 each. Sister plants of the F; generation were
most often quite alike in general vigor and habit of growth whether
self-sterile or self-fertile. Evidently it was such results as these,
together with the persistence of self-sterility even in plants neces-
sarily cross-bred, that led Darwin to the vague suggestion that
the causes of self-sterility of this type are sporadic and chiefly
environmental.

The conditions in chicory in this respect are evidently similar
to those reported for Eschscholtzia, Secale, Cardamine, Nicotiana,

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 423

and the various fruit-bearing plants generally described as self-
sterile. In chicory the sporadic occurrence of plants self-fertile in
varying degrees has given opportunity to observe the comparative
vigor of self-fertilized and cross-fertilized progenies. There has been
no consistent apparent decrease either of vegetative vigor or in
the production of flowers in these self-fertilized lines. Different
lines of descent differ widely in respect to habit of growth, size,
and total number of flowers produced per plant. Some families
of the F; generation were uniformly small, scraggly, sparsely
branched plants, others were short but very bushy and much
branched, and still others were tall, vigorous, and much branched.
These differences seem to be independent of any differences in
the degree of homozygosity and in each family self-fertile and self-
sterile plants were most often as nearly identical in habit of growth,
vigor, and in number of flowers produced as it is possible for two
plants to be. The evidence on this point is still accumulating and
more complete statistical data will be published later.

The contrast between sterility from physiological incompatibility
and sterility from impotence.—Sterility due to physiological in-
compatibility is quite different from that due to impotence as I
have limited these terms above. The distinction has not generally
been made and from the discussions given in the literature one
can not always determine what sort of sterility actually prevailed.
In such discussions of infertile hybrids as that by Wilson (’06)
and by East and Hayes (’12), the different sorts are treated
without any distinction. The sterility which East (’15a) reports
for hybrids between Nicotiana Forgetiana and N. alata grandiflora
is evidently due solely to a physiological incompatibility (germ
cells all fertile in other connections), while that which he reports
(?150) for hybrids of N. rustica X N. paniculata is evidently purely
a matter of impotence (failure to produce spores or gametes).
In 1912 East & Hayes reported the former hybrid as ‘‘fertile’’
and the latter ‘‘partially fertile.’ That a limitation in the
use of terms is necessary is clearly apparent in such cases.

The causes of impotence which result in degeneration of spores,
especially as seen in many interspecific hybrids, it would seem, are
more essentially intracellular in that the incompatibility may
involve a direct relationship within the cells between their idio-
plasmic elements, giving the so-called ‘‘chromatin repulsion.”

424 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Numerous cytological studies of such cases show that the mechani-
cal processes of the reduction division and the reorganization of
the daughter nuclei of the spores are abnormal. What appears
to be chromatin repulsion may be an expression of intra- and inter-
cellular incompatibilities that arise in a hybrid from differences
in the particular types of sex differentiation possessed by the
two parents. Even when the parents exhibit close agreement in
morphological differentiation a wide range of difference may
exist in regard to the relative time of development of sex organs
of which proterandry and proterogyny are marked types. Such
parental differences may first clash when the processes of sex
differentiation in a hybrid are set in motion, resulting in various
grades and types of impotence. This is evidently, in part at least,
what Tischler includes in his view (see especially ’07) that the
impotence of hybrids is the result of differences in the “ Ent-
wicklungsrichtung oder Tendenz’’ of the parental germ cells
which interfere with the normal ontogeny of the hybrid especially
during the critical time of the generative phase of the development.

The production of such conditions as the result of inbreeding
or of continued self-fertilization is certainly very infrequent as
compared with the development in the progeny of wide cross-fertili-
zation. Such impotence on the part of plants was long considered
as an evidence of hybridity, and as a direct result of dissimilarity
in the cells involved, indicating the specific rank of the parents.
Jeffrey (?14) has quite recently emphasized in special reference
to the Oenotheras the familiar conception that such impotence is
a sign of hybridity.

Davis (?150) has also pointed out the high degree of “zygotic
sterility’? (embryo abortion) and pollen and ovule sterility (im-
potence) that prevails in numerous Oenotheras and has suggested
that a selective fertilization (physiological incompatibility) may
also be in operation. He speaks also of ‘‘gametic sterility,’ but
it is not clear whether he refers solely to impotence or to physio-
logical incompatibility (as I have used the terms) or to both.
His general conception that in these cases similarities are elimi-
nated and dissimilarities are perpetuated is, however, purely an
assumption which he brings forward to assist in accounting for
the sporadic and irregular inheritance in the Oenotheras on more
nearly Mendelian assumptions. His investigations are highly

STOUT: POLLINATIONS IN CICHORIUM INTYBUS A2

important in proving the frequency of impotence of various types
and of embryo abortion, and is suggestive that much may be
learned from work with the Oenotheras regarding the causes of
these phenomena.

Not a few investigators have attributed the degeneration of
microspores and macrospores to conditions arising from long and
intensive cultivation. Thus Osawa (’13) considers that such is
the case in Daphne, and Wakker (’?96) has reported that cultivated
races of sugar cane show various grades of such impotence which
are not present in the wild or semi-wild races. In all such cases,
however, the proof that hybridization has not been involved, as
Jeffrey has pointed out for similar cases, is not conclusive.

Attempts to influence or change the degree of impotence in the
case of almost completely impotent interspecific hybrids in tobacco
(Goodspeed and Ayres, ’16) have thus far been negative, which
it would seem emphasizes the view that the causes of such im-
potence are intracellular and only subject to slight, if any,
influences from the general nutrition or physiology of the plant
asawhole. The results reported by Martin (’13) and of Westgate
and Coe (’15) indicate that a plant may be impotent with respect
to development of macrospores in one crop of flowers and potent
in another crop as a result, they assume, of a difference in water
supply determined by the season. Here, however, the impotence
is not, it appears, a degeneration, but a condition in which the
tissues of the pistil remain vegetative. Coit (’15) has, however,
reported that the degree of impotence of pistils in the Washington
navel orange is changed to some extent by climatic conditions.

That impotence involving degeneration should often occur in
the reduction divisions and not in the innumerable somatic divi-
sions that precede, and that such impotent hybrids are often
vegetatively very vigorous, may indicate that after all the so-
called incompatibility may not involve chemical reactions so
much as more purely mechanical relations. It is clear that
fertilization may occur so far as cell and nuclear fusions are con-
cerned and that diploid and often decidedly heterozygous organ-
isms may continue life with vigor only to have the intranuclear
processes, mechanical or chemical, or both, break down during
the more intricate processes of spore formation. There is no
clue in such behavior to the conditions operating in the production

426 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

of such sterility as is in evidence in cases of physiological incom-
patibility in which spores and gametes are formed and in which
the incompatibilities appear to be largely independent of any
direct intracellular relations of the two parental elements in the
germ plasm.

These cases suggest that the phases of fertilization involving
cell fusion are more properly to be regarded as being conditioned
by factors of cytoplasmic differentiation or general protoplasmic
organization, while those of synapsis and reduction are condi-
tioned by the mutual relations of the nuclear and cytoplasmic
elements involved.

The general results of breeding indicate that when the cyto-
plasmic and nuclear relations are such that fertilization can occur,
there is, as a rule, chance fertilization between all gametes irre-
spective of their particular hereditary complex. Such assumed
behavior has been the fundamental basis of Mendelian doctrine.
In the production of the so-called dominants and recessives from
any F; hybrid, gametes that are alike (at least in respect to the
characters involved) combine, while in the production of the
impure members of the same generation gametes that are unlike
are assumed to combine quite as in the production of the parent
F, plants. Homozygosity and heterozygosity are generally as-
sumed to occur with equal chance.

The only incompatibility, if we may call it such, that is assumed
to occur in such cases is that between assumed hereditary units or
factors at the time of the reduction division and here chemical
or mechanical relations are assumed to give pairing and complete
segregation of the elements of the pairs of allelomorphs whether
they both are similar (represent the same character or fraction
of a character), whether they are dissimilar, or whether they
represent the presence and absence of a character. All have been
assumed to segregate with quite their original integrity and value.
While it is becoming very evident that the general doctrine of
unit characters or unit factors and of purity of segregation have
at most only a rather limited application, the general results of
breeding have been assumed to indicate that to a certain degree
similarity and dissimilarity of particular germ-plasm elements
are not in themselves to be considered as definitely limiting
fertility except perhaps in cases where impotence appears. The

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 427

possibility that selective mating of gametes may occur in certain
cases and constitute a factor in fertility and in segregation is,
however, not to be excluded. The assumptions of those who
would ascribe sterility from incompatibility to hereditary line
stuffs or individual stuffs are plainly opposed to the general
Mendelian assumption as to chance mating and pairing of the
newly combined factors.

Further there would seem to be a natural presumption in favor
of the view that chromosome incompatibility resulting in im-
potence is only the extreme stage of a series whose earlier stages
are shown in the phenomena of gametic physiological and morpho-
logical incompatibility and that when in operation it is a very
special grade of differentiation.

It must be recognized that impotence involving various grades
of development of only one of the sex organs is less directly
attributable to an intranuclear incompatibility than are the cases
of nearly equal impotence of both sex organs as seen in numerous
interspecific hermaphrodite hybrids. The various sex forms in
Plantago lanceolata (Bartlett ’13), for example, show gradations
from fully potent hermaphrodites through various grades of anther
and pollen impotence to plants that may be considered as pistillate
only. Here the conditions suggest the operation of physiological
processes in association with the differentiation of male sex organs,
and that in respect to the degree of such impotence an entire plant
is differentiated, much as is the entire organism in the case of
strictly dioecious plants and animals. The occurrence of plants of
Plantago exhibiting various grades of impotence among the flowers
on a single plant (gynomonoecious) (Bartlett 713, p. 174), indicates
the sporadic nature of the physiological processes involved with
this sort of differentiation, as do, likewise, the development of
various grades of hermaphrodite forms in animals, as especially
reported by Goldschmidt (16).

The writer has simply suggested in the introduction and in the
foregoing discussion some of the most obvious types of impotence
of which degeneration of spores is a very marked type. Other
types involving the failure in the formation of flowers or sporo-
phylls, of one or the other kind or of both, or of a general physio-
logical debility are equally in contrast to the conditions prevailing
in the case of the incompatibility as seen in Cichorium, Cardamine,
Reseda, etc.

428 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Significance of serum incompatibilities, etc.—It would seem that
a clue to the processes involved in sterility due to physiological
incompatibility 'might be found in the interactions between the
tissues and the body fluids of different individuals as exhibited
in the results of tissue grafting, in infection and immunity, and in
hemolysis and isoagglutination. Such suggestions have been
made especially by Jost (707), Compton (712, 713), Morgan (710),
and by Lillie (713).

In tissue grafting, both in animals and plants, the degree of
success depends on close relationship, and there are no evidences
that in grafting there is any sort of tissue incompatibility com-
parable to that exhibited in self-sterility or in cross-sterility be-
tween closely related individuals. Here the results seem to
present no analogies unless it can be shown that tissue grafting
in the animals and plants which show self- and _ cross-sterility
behaves differently from the rule and shows the same limitations
as the fertilizations. This is a possibility, and in the absence of
all evidence on this point must be held as such, although it should
be noted that the self-incompatibility exhibited in cases of sterility
in hermaphrodites is not indicated by any incompatibility of purely
vegetative parts or even in general debility or decreased vegetative
vigor.

From the nature of the processes of fertilization in higher plants,
it would appear that, as Jost (’07) has pointed out, any stimu-
lating or inhibiting substances operating in the interrelations of
the tissues involved must be diffusible and must be products of
the cells involved. If this be true, the data regarding the incom-
patibility of normal body fluids of different individuals, as ex-
hibited by the phenomena of agglutination, cytolysis, and pre-
cipitation should be studied with reference to its bearing on the
phenomena of self- and cross-sterility. In agglutination phe-
nomena, which have a distinct value in the clinical diagnosis of
infectious diseases, we see the visible effects of various types of
so-called antigen-antibody reactions constituting a type of reac-
tion between two organisms. Even in interspecific relations,
however, there are exceptions to any general rule of operation:
group reactions show that, even in sharply defined species, specificity
may not exist; ‘‘no two strains of bacteria of the same species are
exactly similar in their agglutinability in the same serum” (Zinsser

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 429

14, p. 229), and the agglutinative characteristics of various
bacteria may be modified by life in different hosts (Smith and
Reagh ’04; Zinsser ’14, p. 231). The quite general application
of the principles of agglutination, however, suggests that similar
reactions may be involved in compatibilities and incompatibilities.
The appearance of agglutination reactions between the blood
cells and the sera of different animals of the same species or strain
(isoagglutination) suggests that at least in the higher animals
types of antigen incompatibility may exist between closely related
individuals. Such reactions have been studied especially in man,
and it has been found (Ottenberg ’11) that, in respect to the
isoagglutination reactions between sera and red blood cells, indi-
viduals fall into four classes: class I, serum will agglutinate red
cells of all members of all other groups, but the red cells of indi-
viduals of the group are not agglutinated by the serum of any
individual of any class; class II, serum agglutinates in classes III
and IV only, and red cells are agglutinated by serum of classes
I and III only; class III, serum agglutinates in class II] and IV
only and blood cells are agglutinable by sera of classes I, II, and
IV: class IV, serum will not agglutinate red cells of any class and
has red cells that are agglutinable by every other class. These
reactions within and between the four groups have been explained
by the assumption of two pairs or sets of reacting substances;
two different active substances (agglutinins x and y), and two
different agglutinable or sensitive substances (X and Y). The
agglutination reaction is assumed to occur only when the two
bloods that are mingled bring together at least one pair x and X
or y and Y. Between bloods of members of any one class there
is no incompatibility in the form of agglutination. The reciprocal
interactions between members of classes I and II, I and III,
I and IV, II and IV .are different. Two reciprocal pairs, II
with III and III with IV, give the same reaction. Also indi-
viduals of the first class constitute about 50 per cent of all persons
examined, and members of the fourth class are relatively rare.
Members of the third group especially often show individual
irregularities and deviations from the rule which it is assumed
involves the presence of another substance, called hemolysin,
which exhibits very sporadically the condition of activity or
latency.

430 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

Furthermore, the studies of isoagglutination phenomena in
steers (Ottenberg and Friedman, 711) show that although there
are groups of individuals with the same characteristics, some of
these groups are different from those in man. In steers the in-
teractions seem to involve but one:pair of substances distributed
in two classes only. The interreactions typical for the various
classes in these different animals are given in TABLE 17, in which
the differences noted are very apparent.

TABLE 17
IN MAN
Sera
Class =
I(xy) | 4I1(Xy) iS ATLeey) Co iv Cea
i | xy _ | — | = | a
ev be eae [ee ae he ee
aX a + | as wd
IN STEERS
Sera
Class —
I(x) II(X) III(o)
2 x | = | — _ |
ws) ye | a | — Pir
~ oO = | —
IN CARDAMINE
| ab | Ab aB AB
ab | _ | — — | <5
Ab = et a leis
aB ve ea Te ae Os
AB — | + at oe

The nomenclature and the grouping into classes especially in
man are strikingly similar to those given by Correns in respect in
the behavior of cross-sterility in Cardamine. In man, however,
the incompatibility (judged by agglutination) is assumed to in-
volve a reaction between two different substances, while in
Cardamine the incompatibility (judged by cross-sterility) is as-
sumed, doubtless falsely, to be a relation between two similar
substances. No agglutination reactions occur between the bloods
of individuals of any class, but in Cardamine only plants of the
class ‘‘ab”’ were cross-fertile among themselves. Correns assumes
that the substances may be also latent when they exhibit no

STOUT: POLLINATIONS IN CICHORIUM INTYBUS A431

interaction. In Correns’ results cross-sterility is considered as a
result of interaction of inhibiting substances and cross-fertility is
an index that there was no action. These interactions expressed
by + and — are represented in TABLE 17. A comparison of the
behavior of cross-sterility between the various classes of Cardamine
and the agglutination reactions between the various groups of
man and steers shows that the only agreement is seen in the ab-
sence of reactions exhibited by class “ab” in Cardamine, the class III
in steers, and class ] in man. Only in classes in which all reacting
substances are assumed to be either latent or absent is there any
agreement.

There is as yet no evidence that these phenomena of isoaggluti-
nation have any relation to the cross-fertility of the animals con-
cerned, for fertility between the individuals showing agglutination
is apparently unimpaired. Thus it is evident that differentiations
do occur, giving so-called incompatibility between blood cells and
sera of animals of the same species which, as far as known, have
no influence on the compatibility of the sex cells themselves.
These observations suggest strongly that analogous reactions may
operate in the cytoplasmic relations involved in the growth of
pollen tubes during the early processes of fertilization, and that
such interactions are not necessarily an index of the direct relations
of the sex cells.

Physicians, however, fully recognize that cases of human
sterility may involve particular incompatibilities which may be of
the nature of those shown in immunity reactions either natural or
acquired. The exact nature of these incompatibilities are, of
course, at present no more understood than are the cases in plants
(see discussion by J. B. De Lee of article by Edward Reynolds,
115), but De Lee believes that they may prove to be related to ag-
glutination reactions.

That sterility may be a type of immunity and that the com-
patibility of the gametes themselves will depend on their consti-
tutional similarity rather than their so-called sex differentiation is,
however, very strongly indicated by the general evidence from
agglutination reactions.

The observations made by Lillie (’12—’16) give strong support
to the doctrine, rather generally discredited among zoologists, of a
specific chemotactic influence of egg secretions on sperms. His

432 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

studies show that eggs of Arbacia and of Nerets give off substances
that produce various visible effects on the sperm of the respective
species. There is ‘‘stimulation of intense activity, which is of
brief duration; (2) an orienting effect expressed in positive chemo-
taxis; (3) an agglutinating action; (4) following these effects more
or less complete paralysis of sperm” (713, p. 554). The so-called
agglutination, however, is held to be an indication of a chemical
action that is necessary for union of ova and sperms. The par-
ticular ‘‘isoagglutinin”’ produced by eggs is called ‘‘fertilizin.’’ Its
action is regarded as similar to that of ‘‘amboceptors”’ in that it
is considered a necessary link in fertilization, combining first with
sperm receptors and then with the egg receptors. The function
of fertilizin is not that of an antibody giving immunity, but rather
that of a sensitizer which makes invasion and fertilization possible.
It does not appear whether the agglutination phenomena here
observed bear a close or a superficial resemblance to the aggluti-
nations of immunity reactions.

In producing evidence in favor of the chemotactic influence of
egg secretions involving the liberation of some such substance as
fertilizin, Lillie has emphasized the importance of internal condi-
tions determined by a particular and specific constitution of the
individuals of a species which are fully self- and cross-fertile.

The discussion of self-sterility by Lillie (?13a, p. 573; 716, p. 51)
and his postulated causes of inhibition of fertilization (’130, p. 528)
are hardly adequate for the known facts. Lillie is perhaps misled
by a misunderstanding of the facts, for he states in reference to the
phenomena of self-sterility ‘‘in species when this occurs the egg
and sperm of the same individual are sterile inter se though fertile
with those of all other individuals” (?16, p. 51). That this is not
necessarily the case has been well shown by Correns whose data
in respect to the variations of cross-sterility are quite like those
which the writer has reported for Cichorium. Furthermore, the
specificity of fertilization according to Lillie involves complete
cross-compatibility between all individuals of a species, and also
full self-compatibility of hermaphrodites. This is hardly com-
parable to the “individual specificity’ of self-sterile hermaphro-
dites whose self-sterility involves an incompatibility of sex cells
equal to that between two different and cross-sterile species.
Sterility and fertility in and between individuals and species are
in evidence and a theory of specificity must provide for both.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 433

If fertilization depends on the production of fertilizin then self-
sterile hermaphrodites that are cross-fertile with certain other
individuals must produce a fertilizin which has selective chemo-
tactic power due to some type or grade of relative physiological
differentiation.

It is obvious that the facts as Lillie has found them require
that the action of the so-called fertilizin must give various grades
of isoagglutination ranging from complete paralysis to complete
reversal and recovery paralleling the fluctuating conditions of
fertilization quite generally emphasized by studies on Cvzona,
Cardamine, Cichorium, Primula, etc. Furthermore, the egg
extracts of Arbacia are also agglutinative of sperms of Nereis with
action that is violent and extremely toxic. Evidence is produced,
however, to show that this so-called heteroagglutinin is another
substance than the so-called isoagglutinin (fertilizin). The inter-
relations of these secretions of ova to fertilization and normal
development after fertilization need to be fully investigated
especially as the action of fertilizin, assumed by Lillie to be neces-
sary for fertilization, is repeatedly spoken of as a type of incom-
patibility which ‘‘certainly lessens the fertilizing power of the
sperm’”’ (?13a, p. 556).

The phenomena of agglutination effects in these lower animals
evidently afford a field for further careful investigation. The
analysis of the chemotactic influence of egg secretion should be
extended to such hermaphrodites as Ciona, of which different
strains exhibit various degrees of self-fertility and also to such
species as can be grown in pedigreed cultures in which the self-
and cross-incompatibilities (judged by fertility) are as varied and
fluctuating as are those in Primula, Lythrum, Cardamine, and
Cichorium.

Von Dungern (’02) reports, previously to Lillie’s studies, that
so-called sperm heteroagglutinins are produced by certain species
of Asterias and Echinus reciprocally, but not by other species. His
studies were made with extracts from crushed eggs rather than
from the secretions of eggs. He considers that the agglutinations
check or inhibit interspecific fertilizations. He further injected
ova and sperm of the same species separately into rabbits and
found that both led to the production of sperm agglutinins in the
blood of rabbits. The relation of such induced agglutinins to

434 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

those normally existing in the eggs of another species is, of course,
not determined, and their further relation to such isoagglutinins
(fertilizin) as Lillie reports is an open question. The results,
von Dungern points out, emphasize the obvious fact, which, how-
ever, has been somewhat disregarded, that the protoplasm of both
sex cells are fundamentally of similar constitution. He further
reaches the general conclusion at which I have arrived, that suc-
cessful fertilization is not dependent on differences between ova
and sperms, but on the similarity of their protoplasmic constitution.

Studies of precipitation have shown that the introduction of
foreign proteins of any kind into the circulation of an animal will
lead to the development in that animal of the property of causing
precipitation when the serum of such an animal is mixed with clear
solutions of the respective protein. Thus far, such studies empha-
size the similarity of the proteid metabolic products of the indi-
viduals of a strain and have thus been concerned as tests of bio-
logical relationship not only of animals but of plants (Magnus
and Friedenthal ’06, ’07a and 6; Magnus ’08).

As far as is now known, isoprecipitins, although present in some
animals to some degree, are very irregular in appearance and
power. Here, as in agglutination phenomena, there is no known
reaction that could account for self-sterility, although it must
be considered as possible that refined methods of technique may
show similar reactions between the metabolic products of two
such organs as pistils and pollen tubes. The so-called “‘organ
specificity’ in which antigen antibody reactions depend on organs
rather than on genetic relationship may furnish a clue to certain
phases of the general problem of sex differentiation and the proc-
esses of fertilization especially in highly developed organisms.
Here, however, there is a constitutional and chemical similarity
in large degree irrespective of anatomical structure quite as in
cross-fertility in which specific anatomical identity is not a certain
criterion for predicting cross-fertility. That a certain degree of
similarity exists in the properties of pollen of different species as
well as in the pistils is evident from the results of cultural studies
of pollen-tube growth, and it is evident that this is not determined
by particular and specific morphological characteristics.

It should be noted in this connection that Magnus and Frieden-
thal (07) have presented data showing that in rye the extracts of

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 435

seed, pollen, roots, and shoots give quite the same precipitations
in the sera of animals previously treated with extracts of either
shoots or pollen of rye. From these results they conclude that all
cells of an individual possess the precipitation properties of the
species.

However, there is some evidence that the general specificity of
a species may be modified or limited to some degree by types of
isoantibody reactions (isoprecipitations, isoagglutinations, 1so-
spermatotoxins, etc.). Also the specificity of the individual is
limited by well-marked cases of organ specificity. These con-
siderations certainly suggest that a further refinement of the
precipitation method of analysis may reveal still more delicate
but nevertheless important types of incompatibility in the inter-
relations between the cells of such highly specialized organs as
pistils and pollen tubes or ova and spermatozoa, and which may
be comparable to the cases of so-called autosensitization. In
this respect the appearance of self-sterile plants and animals may
perhaps involve the development of some type of acquired im-
munity, concerned with the metabolic products of closely related
though specifically differentiated tissues. Still it must be admitted
that high fertility and vigor, as Burck maintains, is present in
naturally self-fertilized and in cleistogamous forms in which it
would seem there would be greatest chance for the development
of such immunity.

It is especially significant that the prevalent conceptions of
the operation of antigen-antibody reactions are based upon the
feeding or nutritive activities of the cells. The reactions are
assumed to be cellular and, on the whole, individual. A new-
born organism may acquire immunity or show various types of
sensitization through the general property of its cells to react in
much the same way as the parents were able to do. There is at
least only an indirect heredity, in that characteristics of the
species or race delimit the general range of its possible variations
of intercellular reactions.

It is highly probable that an extension of the knowledge of
colloidal relations may decidedly modify the older chemical con-
ception of antigen-antibody reactions, at least for precipitation
and other closely allied phenomena in which the relative con-
centrations of substances involved are important. In serum

436 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

precipitation, for example, an excess of antigen frequently inhibits
precipitation, a phenomenon quite analogous to the inhibition
zones in colloidal flocculations in which the relative quantity is
more important than the chemical nature of the substances.
The whole theory of precipitation and agglutination phenomena
rests on an assumed differentiation in the chemical or physical
properties of the products of individuals or of different organs of
the individual. The reaction occurs, it is assumed, because of
dissimilarity. One could conceive of such conditions arising from
the differentiation of sexual organs borne by the same plant and
of fluctuations that would allow for such variations in self- and
cross-fertility and sterility as do appear in chicory. Thus far,
however, there are no well-marked or general data as to the
behavior of isoagglutinins or isoprecipitins which are entirely
parallel to the cases of incompatibility giving self-sterility. That
the phenomena do indicate that sexual compatibility is propor-
tional to similarity of the organisms or gametes rather than to
dissimilarity or differentiation is, however, strongly suggested.

The phenomena of pollen-tube growth—Extensive experiments
have been conducted to determine the physiology of pollen
tubes both in reference to direct growth in pistils and their extracts
and to their behavior in different methods of artificial culture.
The knowledge thus gained bears on the problems of sterility,
especially from the standpoint of an understanding of (1) the
requirements for germination, (2) the extent to which pollen-tube
growth is determined by physical or local conditions or by its own
initiative, in contrast to (3) the extent to which its growth is
influenced by direct secretions of the ovule with its egg. The
results with different species show such wide differences that it is
difficult to establish any general rule of behavior in respect to any
one of these questions.

The older opinion that specific chemical substances or condi-
tions are necessary for germination of pollen is hardly tenable in
view of the very general germination of pollen on pistils of widely
different species (especially reported by Strasburger 1886, and by
Tokugawa 714), and of the very frequent observation that germi-
nation occurs in pure water (Molisch ’93; Lidforss ’96), and that
a proper control of the water supply is often all that is necessary
to secure germination even in cases in which the difficulty of

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 437

securing germination had been considered as an evidence of highly
developed specificity in requirement (Jost ’05, ’07; Martin 713;
Tokugawa 714).

It has been shown that pollen tubes of a species often make best
growth in and show a marked chemotropism to a particular sub-
stance, and that in cultures usually a particular concentration
gives the best growth. The limitations and uncertainties of the
methods of artificial culture are most evident. The best results,
as Jost points out, show a rather feeble growth; usually the tubes
only reach a length that does not exceed a few diameters of the
pollen grain. In corn, for example, the best growth reported by
Andronescu (’15) was equal to 3-5 diameters of the pollen grain
and was therefore only a very small fraction of the length of the
style and stigmaof corn. Many cases reported as germination may
not be due to real growth but simply to swelling by tugor. The
’ results of studies in germination are most often of questionable
value owing to the lack of an adequate criterion of what constitutes
natural germination and growth.

The best growth reported by Adams (’16) in his studies of the
germination of pollen of the apple is 1336 w and of black currant
is 688 wu, which in length is about 30 and 12 times the diameters of
the respective pollen grains. Under the microscope this appears
to be a vigorous growth, but when we consider that the growth is
only 11% millimeters in length itis, in comparison, hardly sufficient
to do much more than penetrate the stigma. The limitation of
such results in explaining process of pollen-tube growth in the
intricate relations of fertility and sterility is apparent.

In pistils themselves it has been shown that pollen tubes advance
by mechanically penetrating through the pistil or by following
stylar canals, that they may (in experiments) grow in the reverse
direction from that which is natural, and that there is no marked
difference in culture tests between the chemotropic power of
different sections of the pistil.

Nearly all investigators have agreed that the growth of the
tubes into the micropyle must be influenced by some sort of secre-
tions of the egg itself, but it is not fully established just what this
influence is or to what distance it acts.

The difficulty of establishing the fundamental facts regarding
the relations of pollen-tube growth to the secretions and cell

438 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

products of styles and of ovules in forms fully self- and cross-fertile
is fully indicative that a decided refinement of method is neces-
sary to determine the conditions operating in such fluctuating
cases of fertility as are seen in self- and cross-incompatibilities.

It has, however, been quite generally shown, in agreement with
Jost’s (’07) results, that in self-sterility from physiological incom-
patibility the tubes grow more slowly and do not penetrate to
the ovary in the time required for fertilization. This has been
taken as evidence of the inhibitory action of specific stuffs (indi-
vidual stuffs of Jost, line stuffs of Correns) or of the lack of proper
nutritive substances (Compton ’13; East ’15a). Certain phases
in the determination of this point admit of experimental proof
and the writer is planning experiments in this particular. If
pollen tubes admitted of ready growth in cultures, extracts of
inhibitory or stimulating substances might be made and their
action determined. Thus far, however, no essential differences
have been found in the physiology of the pollen of self-fertile and
self-sterile plants of the same species. It would seem that some
such differences must exist comparable to the marked differences
in the growth of pollen tubes in the ineffective and the effective
pollinations. The difficulty of securing any sort of germimation
in chicory seems to prohibit this sort of study in this plant.

Some misunderstanding appears to have arisen in regard to the
results of certain investigators. Jost’s determination that a par-
ticular structure of the epidermis prohibits germination of pollen
in Corydalis cava gives no clue to the causes of self-sterility in this
species, as such a condition prohibits the germination of all pollen.
After the epidermis is broken the plant’s own pollen will germinate
as will the pollen of other plants, but its growth is more feeble.
The cause of self-sterility is here not concerned with the germina-
tion of the pollen. Likewise in Cytisus Laburnum the term self-
sterility is used by Jost, inadvisedly, for here the structure of the
epidermis seems to make the injury of stigmas necessary for the
growth of any pollen and hence it is not self-sterility but complete
sterility that is conditioned by an unbroken epidermal surface.
These. are interesting cases of very special adaptations that favor
cross-fertilization.

Martin (’13) has drawn the highly suggestive conclusion that
in red clover the necessity for a delicate regulation of water supply

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 439

is so great that the excess supplied to pistils through the transpira-
tion current of plants in wet seasons may be a cause of marked
sterility in this species. It does not appear, however, that this
is the actual cause of the self-sterility which seems to prevail in
this species, for self-sterility is in evidence even under the condi-
tions most favorable for cross-fertilization, and the marked sterility
of a plant in the first crop seems to be more closely related to the
impotence of pistils in that its tissues remain vegetative. Later in
the season the same plant may produce a new crop of flowers with
functional pistils but with the plants highly self-sterile from
physiological incompatibility but highly cross-fertile as pollinated
in the field.

Tokugawa’s recent study gives no data that are directly con-
cerned with the problems of self-sterility, although he worked with
the pollen of several species known to be self-sterile. His results
relate chiefly to a comparison of pollen-tube growth in cases of
rather wide crossing and give no clue to the causes of self- and
cross-sterility in such cases as chicory and Cardamine.

Favorable or unfavorable growth of pollen tubes may, to a con-
siderable degree, depend quite as much on quantitative as on
qualitative relations, not only in respect to such incompatibilities
as are shown in the precipitation reactions but in the case of stimu-
‘lating or inhibiting substances. Miyoshi (?94) has emphasized
this point in presenting data on pollen-tube growth, which show
that to divert tubes from one solution to another it is necessary to
increase greatly the concentration of the second, as would be
expected from Weber’s law.

There can be no doubt that in the same strain different plants,
and even different pistils on the same plant, possess variations in
the total and relative amounts of materials that may serve for
the nutrition and stimulation of pollen tubes, and that pollen grains
possess considerable variations in their own supply of nutritive
materials and in their requirements for growth. Such variations
are operating in all cases of self-fertility. The causes of self- and
cross-sterility are, however, quite independent of these.

The final stages of growth of pollen tubes in pistils should be
more adequately determined with reference to the relative de-
velopment of the macrogametophyte and the egg. It is highly
essential to know the degree of development of the macrogameto-

440 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN -

phyte in reference to what may be called the critical point in the
growth of the pollen tube. It is highly possible that the style
and stigma get their differential qualities by diffusion of secretions
(hormones) from the gametophytes after reduction has occurred.

Types of sterility in dimorphic and trimorphic species.—Thus far
we have considered the phenomena of sterility (chiefly physio-
logical incompatibility) that appears in such non-dimorphic species
as Eschscholtzia californica, Cardamine pratensis, and Cichorium
Intybus,in which, as has been emphasized, there is no anatomical
incompatibility in the relative differentiation of sex organs of the
different plants. The evidence at hand, however, indicates that
quite similar if not identical types of incompatibility also exist
in various dimorphic and trimorphic species. Here, as Darwin
(62, ’64, ’65, ’69) and Scott (’65) have especially pointed out,
various morphological differences and similarities indicate in a
general way the combinations that Darwin proposes to call
legitimate and illegitimate, which are terms highly useful in a
careful analysis of the relations in dimorphic and _ trimorphic
species.

The real bearing of sex heteromorphism will become clearer if
we summarize the general facts of sex differentiation. We evi-
dently need, in a consideration of all these conditions, a more
accurate classification of the grades and types of differentiation
that are in evidence. In respect to differentiations of sex that are
either morphological or physiological, or correlations of both, we
may quite readily distinguish in flowering plants such grades as
the following:

I. Differentiation of organs within an individual plant.

1. General sex differentiation as ordinarily recognized, giving
male and female sex organs with both exhibiting a
certain degree of morphological and functional difference,
but maintaining essential constitutional organization.
Differences in time of development, giving grades of
proterandry and proterogyny, especially when seen in
perfect flowers, may be included here.

2. Differentiation between different flowers, giving grades of
maleness and femaleness to a flower as a unit (pistillate,
staminate, perfect, or neutral as in monoecious, or
polygamous, forms) or in various composite combina-
tions.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 441

3. Differentiation between the male sex organs.

a. In different flowers; from complete absence through
various grades of development and function.

b. In a single flower giving heterodelphy of stamens;
purely morphological (?), as in species of Labiatae,
Cruciferae, and Scrophulariaceae; both morphologi-
cal and physiological, as in Lythrum Salicaria;
possibly cases purely physiological.

4. Differentiation between the female sex organs.

a. In different flowers; from complete absence through
various grades of development and function.

b. In a single flower; no marked cases in evidence.

5. Differentiation within a reproductive organ, among the
spores and gametophytes developed by or from any one
sex organ; morphological or functional or both as a
result of (a) sporadic variation, (0) of the intricate proc-
esses of reduction division, or (c) from other unknown
causes.

II. Differentiation between individuals as wholes.

1. In the degree of maleness or femaleness; in which entire
plants differ in the total differentiation in one or more
lines indicated under I; seen in dioecism, polygamo-
dioecism, various grades of monoecism and intersexes
such as Goldschmidt has described in moths.

2. In respect to male sex organs alone; giving various grades
of development from presence to absence, or giving
distinct types of stamens for different plants as in
Primula, Lythrum, etc.

3. In respect to female sex organs; parallel with 2 above.

4. In respect to the particular combination of the various
types of sex organs; (more involved and of different
grade than I above), giving different plants with quite
different types of perfect or imperfect flowers as also in
Lythrum.

(In 1, 2, 3, and 4 above, morphological differentiations are
strongly in evidence; physiological correlations clearly in evidence
in certain cases; purely physiological differentiations suggested by
such cases as Cichorium.)

III. Differentiation between groups of individuals.

442 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

I, 2, 3,—x. The appearance within a species of one or more
groups of individuals which are respectively similarily
differentiated with regard to certain types, grades, or
combinations of differentiation as indicated in I and II.

The existence and interrelations of various types of these differ-
entiations with reference to the questions of sterility may be
illustrated by those cases in which incompatibilities giving sterility
are best known.

In Linum grandiflorum (Darwin, ’64) there is such anatomical
differentiation that two groups (usually spoken of as forms) of
individuals exist in respect to the type of pistil present in the
perfect flowers. The flowers of all individuals of one form have
long styles and short stamens; those of the other form have short
styles and short stamens. Aside from this evident morphological
differentiation there is a correlated functional differentiation. All
plants show marked self-sterility, according to the evidence; thus
within the individual there is a degree of functional differentiation
of the sex organs that gives self-incompatibility. It can not be
too strongly emphasized that this is not correlated closely with
anatomical differentiation, for long-styled plants are fertile with
pollen from short stamens of plants of the other form, but sterile to
its own short stamens. Also a short-styled plant is fertile with
pollen of short stamens of a long-styled plant, but sterile with
pollen of its own short stamens. This is quite identical with the
behavior of cross-fertility and cross-sterility in Cichorium with
the exception that in Cichorium the differentiation is purely
physiological.

Darwin reports complete intra-form incompatibility in Linum;
plants of the same form are cross-sterile; the two sex organs of
different plants of the same form show the same incompatibilities
exhibited by the two sex organs of the single plant. The morpho-
logical differences are certainly not indicative of the incom-
patibilities. Many highly self-fertile species show greater rela-
tive morphological differences than are here seen even in the long-
styled form.

In several species of Primula (Darwin ’62; Scott ’65) there is a
further anatomical differentiation between the two forms in that
they differ in the relative length of both sex organs: one form has
long styles and short stamens, the other has short styles and long

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 443

stamens. A third form may here arise with stamens and pistils of
nearly equal length and intermediate between the lengths in the
other two forms (see diagram by Scott ’65, p. 109). Here also
all plants are evidently more or less self-fertile, the plants of the
non-dimorphic form being highly self-fertile. There is also marked
fertility of intra-form crosses. The inter-form crosses are, how-
ever, more fertile; a condition that very clearly arises from the
fact that the relative morphological and physiological differentia-
tion of the sex organs involved is such that the greater degree of
similarity exists between the male and female organs borne by
plants of different forms.

Still another degree of morphological differentiation in herma-
phrodites with perfect flowers is seen in Lythrum Salicaria (see
diagram by Darwin, ’65, p. 171), in which three forms differ in
regard to length of styles and in the particular combination of
three different types of stamens. The forms are all different in
respect to pistils but each is like another form in respect to one
set of stamens. A special point of interest is the differentiation
in the male sex organs in a single flower, which are relatively
morphologically differentiated quite as are the two sets in various
species of Labiatae and Cruciferae. Here, however, there are
various physiological or functional differentiations, giving various
grades of compatibility. All plants are apparently strongly
self-sterile; there is marked sterility in intra-form cross-pollina-
tions (all illegitimate); there is also marked sterility in inter-
form pollinations, involving stamens and pistils of different
lengths (illegitimate), but high fertility if legitimate pollinations
are made. In inter-form crosses any one plant is both sterile and
fertile to another plant according to the pollen used. We have
here, perhaps, the most convincing evidence that in one indi-
vidual the male sex organs may exhibit further differentiation,
giving two sets of stamens in which the stamen as a whole, and
each set as a whole, are differentiated quite independently of any
differentiation that may exist between the spores produced by a
stamen.

The degrees of functional differentiations that exist in such
plants as those above mentioned are conspicuous because they
exist in more or less marked correlation with structural differ-
entiations. They are, however, revealed only in the degree of
fertility and sterility that results.

444 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

That functional differentiation may exist quite independently
of morphological differentiation is equally conspicuous im the
frequent cases of self- and cross-sterility where perfect anatomical
compatibility is present. Furthermore, functional differentiation
is subject to wide fluctuations and is by no means necessarily
related to morphological differentiation. This is seen in the
different grades and intensities exhibited by Linum grandzflorum,
Primula sinensis, and Lythrum Salicaria; by the different grades
that exist in numerous species of Primula; and most especially by
different grades and intensities of functional differentiation
existing within a species or within a single form as judged by
the immediate results of pollinations and the character and
behavior of the respective offspring.

With Lythrum, for example, Darwin obtained various grades of
fertility from illegitimate intra-form pollinations for all these
forms, showing that various grades of physiological incompatibility
exist independently of morphological differentiation. The illegiti-
mate offspring exhibited a wide range of variation with respect to
vigor, impotence, and fertility (the latter judged wholly by cross-
pollinations, mostly open and legitimate). Only in one set of
19 plants (sisters?) was provision made for exclusive intra-form
pollinations (’69, p. 398, 399). As these were all of the long-
styled form they were illegitimate offspring illegitimately polli-
nated. Of these only three plants are fully reported: one pro-
duced a large crop of capsules and was decidedly fertile; one pro-
duced few capsules with less seed per capsule; the third flowered
profusely, no impotence is mentioned, but the plant produced few
capsules which, however, contained so many seeds that Darwin
states ‘‘the average and the maximum are so remarkably high
that I cannot at all understand the case.’’ No attempt was made
to study controlled self-fertilization on any plants, and no attempt
was made to make comparisons of the relative degrees of incom-
patibility which the data suggest must exist in and between
various plants even of the same form. ‘The studies of illegitimate
offspring were also extended only to the first generation.

With Primulas, there is, it appears, a rather weak incom-
patibility in illegitimate self- or intra-form fertilizations. Dar-
win’s most extended experiments in inbreeding a form were with
the long-styled form of P. veris (77, p. 219), in which four gener-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 445

ations were grown (illegitimate). These were ‘healthy and
fertile” and “their fertility even increased in the later generations
as if they were becoming habituated to illegitimate fertilization”’
(p. 219). Such evidence shows that variations and fluctuations
in self-compatibility and inter-form compatibilities may be so great
that highly fertile strains may be derived just as an entire species
may be non-dimorphic and either long-styled or short-styled
(Scott 65).

Spontaneous variations involving in marked degree both mor-
phological and functional differentiation are seen in the frequent
appearance of highly fertile equal-styled strains in several species
ome rigmin (Scott: "65> Darwin’’69,.?'7'7):

The rather extended and more recent studies with Primula by
Bateson, Gregory, and others have not been directed to such
studies as give further light on the different grades of self- and
cross-incompatibilities that exist in and between different lines of
descent. From the general grouping of their data it appears
(Gregory 711, p. 83) that legitimate fertilizations are more fertile
than illegitimate fertilization. Gregory further notes that the
short style is dominant over the long style, but that in F; gener-
ations from such a cross there are less short-styled plants than
would be expected on the Mendelian conception of the integrity
of characters as units. He suggests that this may be due to
differences in the fertility of various gametic unions, giving real
selective fertilization or selective embryo abortion, but he evi-
dently recognizes that the degree or grade of fertility between
the same types of gametes may differ in different races. In all
these studies the relative fertility of pedigreed lines of self-fertilized
long-styled or short-styled plants is not indicated, and it is not
even clear that such lines were grown in the genetical studies.

The general behavior of these plants is of special significance
in the consideration of whether physiological incompatibility
involves too great or too little differentiation, and of the greater
problem whether the success of fertilization is most dependent on
similarities or dissimilarities. Darwin fully realized that illegiti-
mate self- and cross-sterility can best be considered as due to
‘“incompatibilities’’ that are more functional than morphological,
and he even held that in self-fertilization and intra-form fertiliza-
tion the incompatibility is in some cases of the same grade.as that

446 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN-

existing between species (’69, p. 436). The infertility even in self-
fertilization is here definitely considered as involving too great
a dissimilarity that is essentially a physiological differentiation.

Jost’s consideration of the cross-incompatibilities of intra-form
fertilization indicates that the doctrine of individual stuffs does
not adequately account for the results here obtained. He sug-
gests that different concentrations of the assumed individual stuff
may exist in organs of different length and from his discussion it
appears that illegitimate cross-pollinations which should be fertile
because involving different stuffs are not fertile because of a
particular concentration. Thus certain degrees of concentration
of the individual stuff in sex organs of two different plants are
assumed to influence the degree of cross-fertility even to the
extent of prohibiting cross-fertilization.

Darwin failed to see that the incompatibilities giving sterility in
non-dimorphic species such as Eschscholtzia californica and Reseda
odorata are undoubtedly of the same nature as those giving self-
sterility in plants of dimorphic and trimorphic species. This was
perhaps largely due to the fact that he did not know of cross-
incompatibility in such plants as Cardamine and Cichorium, which
give group reactions with reference to interrelations quite as do
the dimorphic and trimorphic species. He further confuses the
whole subject in his culminating work on self- and cross-fertiliza-
tion by speaking of illegitimate pollinations of dimorphic forms as
similar to self-fertilization of a non-dimorphic species (’?77, p. 343;
p. 351), largely on the conception that both were similar in respect
to effect on fertility.

The evidence from the various species of dimorphic and tri-
morphic species clearly shows that morphological and functional
differentiation of various grades and degrees of intensity are in
evidence in and among plants of the same blood relationship;
that the two are not necessarily closely related; that both are
subject to fluctuations and sporadic variations; and that the
incompatibilities giving sterility even in self-pollinations are to be
considered, as Darwin evidently held, as resulting from too great a
related differentiation of the organs and cells involved in fertiliza-
tion.

In the various dimorphic and trimorphic species each form is
composed of individuals whose flowers are morphologically differ-

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 447

entiated as a whole from those of another form. Yet the differ-
entiation, anatomical and physiological, between the two sex
organs of a single flower or a plant as a whole is such that there is
too great a difference for self-fertilization. The reciprocal differ-
entiation, however, between sex organs of different forms is
such that the two sex organs of the different plants are as a rule
more compatible than are those on the same plant. Jost’s con-
ception of an influence of differences in the relative concentration
of individual stuffs in organs of the same plant or of different plants
is an attempt to analyze the physiological conditions of such
differentiation.

CONCLUSION

Sex differentiation giving male and female plants, male and
female organs, and male and female gametes, involves various
obvious grades of anatomical and. functional difference. This
differentiation is what makes sex obvious and has led to an un-
warranted emphasis of the view that the compatibility of sexes
and the fusion of sex cells depends on such differences. The
manifold limitations of cross-fertilization in the higher plants
show that anatomical differences are to a large degree superficial,
that there can be no doubt that constitutional dissimilarities are
responsible for the great number of incompatibilities existing
between individuals, and that the most fundamental principle of
sexual fertility 1s that a marked degree of similarity in constitution
1s necessary.

The presence of self-sterility and intra-form sterility in such di-
morphic and trimorphic species as Linum grandiflorum and Lythrum
Salicaria might seem to indicate that the grade of visible differ-
entiation between the sex organs and sex cells of a single individual
has been carried so far that there is sufficient constitutional dis-
similarity to give even self-incompatibility. But the presence of
both self- and cross-sterility within a non-dimorphic species or
strain as in Cichorium Intybus shows that incompatibility is funda-
mentally independent of visible differentiation.

On the whole, the evidence favors the doctrine that for success-
ful fertilization the element of similarity in cell organization and
in the physical, chemical, idioplasmic, and structural properties of
all the cells and tissues involved is more important than any
dissimilarity which can be associated with sex differentiation.

448 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Particular idioplasmic elements of the nucleus of the sex cells
must, it would seem from the occurrence and only sporadic inherit-
ance of self-sterility, have less direct influence on the possibility
of successful fertilization than has the individually developed
epigenetic cell organization of the parent individual and the grade
of relative constitutional differentiation that may arise in the
development of the two sexes even on a single individual.

Inbreeding and self-fertilization are often highy beneficial, as
Darwin noted. Burck (’08) argues at length from good grounds,
as noted above, that self-fertilization is the most effective means
of reproduction. The evidence is clear that self-sterility prevails
in plants that are necessarily cross-bred and that when self-fertile
plants do appear inbreeding does not decrease the fertility. Speak-
ing broadly, similarity favors gametic fusion.

Self-sterility due to differentiation giving dissimilarity, when it
occurs, may have manifest advantages in evolution on the assump-
tion of an increased number of variants that come from crossing
and the direct increase of the intensity of variation that may
thus appear over that in self-fertilized strains or that which
arises by somatic variation. With the development of self-
incompatibility a certain amount of cross-incompatibility comes
unavoidably by heredity either between closely related (simi-
lar) or between more distantly related individuals. Types and
grades of sex differentiation that are essentially physiological,
if such are to be assumed as determining fertilization, have doubt-
less been acquired just as proterandry or heterostyly, and other
numerous anatomical incompatibilities have been acquired. Their
transmission in out-crosses, however, is an unusually perfect
example of sporadic inheritance in which vague tendencies only
can be recognized.

The results in chicory show that the development of self-incom-
patibility is not to be closely correlated with conditions in the
immediate parentage. Every plant is, of course, the product of
the fusion of two gametes, yet when self-sterile its gametes are
inhibited from fusing. The apparent contradiction is equally
present on any theory of sex. Such considerations, as already
noted, emphasize the sporadic quality of the phenomenon of self-
sterility.

Thus far the development of self-sterility, due to physiological

STOUT: POLLINATIONS IN CICHORIUM. INTYBUS 449

incompatibility, from strains previously fully self-fertile has not
been observed in cultures or produced either by inbreeding or by
wide crossing, showing that it is quite in the category of such
deep-seated characters as those of heterostyly and proterandry,
and such sex differentiation as that of individuals as wholes.
East’s (’15a) results with tobacco are most suggestive of the
origin of self-sterility through crossing, but as he is inclined to
consider the parent species as also somewhat self-sterile, this point
is in doubt in this case. Still the production of types of impotence
by wide crossing is proverbial, and we may find that the production
of self-sterility due to physiological incompatibility is equally
frequent. Impotence is no more directly and simply hereditary
in outcrosses than is self-sterility. As in chicory, all known cases
of sterility from physiological incompatibility have been studied
only in species and strains in which it was already well developed,
at least to the extent that some plants were thus self-sterile.

It must be fully recognized that the wide variations in the
expression of incompatibility through sterility may, to a marked
degree, mask the underlying tendencies of development. This is
especially true when we consider the behavior of sterility and
fertility in heredity. In my cultures of chicory self-fertile plants
arose from self-sterile parents. The study of the offspring of such
plants gives direct evidence on the heredity of the characteristic
of self-fertility immediately after its appearance in a line of descent.
The tendency is strong for complete self-sterility to develop among
various individuals of the offspring of these self-fertile parents:
but on the other hand there is a nearly equal tendency for self-
fertility to develop among such offspring. These two tendencies
illustrate what may be called the inertia of cell organization as
expressed in heredity. The particular somatic conditions in an
individual and the particular grade of sex differentiation are not
fully transmitted through spore formation and the formation of a
new zygote. No doubt this sporadic nature of the character is
chiefly due to the fact that the particular type of organization and
differentiation which existed in the parent is not duplicated in the
various offspring. The agreement is, however, sufficient to main-
tain a marked degree of fertility. On the other hand the varia-
tions are sufficient to give constant fluctuations in self-fertility
about a rather fixed mode. To what extent the mode in chicory

450 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~

or in other plants can be shifted by continued inbreeding or self-
fertilization remains to be seen.

In the physiological incompatibilities that appear in the selfing
and crossing of such non-dimorphic species as Cichorium Intybus
and Cardamine pratensis, as well as in such dimorphic species as
Primula sinensis, we see very clearly that the grade of sex differ-
entiation within the individual may involve a relative dissimilarity
sufficient to limit greatly or even prohibit successful fertilization.
The nature of the differentiation in the sex organs of different
plants can also be such that all grades of both self- and cross-
compatibility and incompatibility may exist, as the results in
Cichorium fully indicate. The phenomena, on the whole, seem
most consistently interpreted on the general conception that the
possibility of successful fertilization depends on constitutional
similarities rather than dissimilarities.

BIBLIOGRAPHY

Adams, J. 1916. On the germination of the pollen grains of apple
and other fruit trees. Bot. Gaz. 61: 131-147.

Andronescu, D. I. 1915. The physiology of the pollen of Zea Mays
with special regard to vitality. Thesis, Univ. of Illinois.

Backhouse, W. O. i911. Self sterility in plums. Gard. Chron. 50:

299.
Bartlett, H. H. 1913. Sex forms in Plantago lanceolata. Rhodora 15:
173-178.

Baur, E. 1911. Einfiihrung in die experimentelle Vererbungslehre.

Burck, W. 1908. Darwin’s Kreuzungsgesetz und die Grundlagen der
Bliitenbiologie. Rec. Trav. Bot. Néerl. 4: 17-118.

Castle, W. E. 1896. The early embryology of Ciona “intestinalis
Flemming (L.). Bull. Mus. Comp. Zool. Harvard Univ. 27:
201-280.

Con, 1. E.. -1915... Citrus truits.

Collins, G. N. 1914. A more accurate method of comparing first
generation maize hybrids with their parents. Jour. Agr. Re-
search 3: 85-01.

Compton, R. H. 1912. Preliminary note on the inheritance of self-
sterility in Reseda odorata. Proc. Cambridge Phil. Soc. 171.

———. 1913. Phenomena and problems of self-sterility. New Phyto-
logist 12: 197-206.

_Correns, C. 1912. Selbstststerilitat und Individualstoffe. Festsch.

Med. Nat. Ges. z. 84. Versam. Deutsch. Naturf. u. Arzte.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 451

———. 10913. Selbststerilitat und Individualstoffe. Biol. Centralb. 33:
389-423.

Coville, F. C. 1914. Blueberry culture. In Bailey, L. H. Standard

Cyclopedia of Horticulture 1: 515—517.

1915. Directions for blueberry culture, 1916. U?.Sy) Dept:
Agr. Bull. 334.

Darwin, C. 1862. On the two forms, or dimorphic condition, in the
species of Primula and on their remarkable sexual relations.
Proc. Linn. Soc. Bot. 6: 77-96.

1864. On the existence of two forms, and on their reciprocal
sexual relation, in several species of the genus Linum. Proc.
kann Soc. Bot.!77 69-33:

—-—, 1865. On the sexual relations of the three forms of Lythrum
Salicaria. Proc. Linn. Soc. Bot. 8: 169-196.

_._ 7868. Animals and plants under domestication. Vol. II.

Edition by Orange Judd Co., New York.
1869. On the character and hybrid-like nature of the off-
spring from illegitimate unions of dimorphic and_ trimorphic
plants. Proc. Linn. Soc. Bot. 10: 393-437.
===, 1877. Cross and self fertilization im. the vegetable kingdom.
Edition by D. Appleton Co., New York.

Davis, B. M. t1gi5a. A test of a pure species of Oenothera. Proc.
Am. Phil. Soc. .54: 226-245. r

————. 1915. A method of obtaining complete germination of seeds
in Oenothera and of recording the residue of sterile seed-like
structures. Proc. Nat. Acad. Sci. 1: 360-363.

Dorsey, M. J. 1914. Pollen development in the grape with special
reference to sterility. Agr. Exp. Sta. Univ. Minnesota Bull. 144.

Dungern, E. von. 1902. Neue Versuche zur Physiologie der Befruch-
tung. Zeit. Allgem. Physiol. 1: 34-55.

East, E. M. 1915a. The phenomenon of self sterility. Am. Nat. 49:

77-87.

1915). An interpretation of sterility in certain plants. Proc.
Aim: Phils Soc. 54: 70-72:

East, E. M., & Hayes, H.K. 1911. Inheritance in maize. Connecticut
Agr. Bxp.ota. Bull. 167.

1912. Heterozygosis in evolution and in plant breeding.
U.S. Dept. Agr. Bur. Pl. Ind. Bull. 243.

Focke, W.O. 1890. Versuche und Beobachtungen iiber Kreuzung und
Fruchtansatz bei Bliitenpflanzen. Abh. Nat. Ver. Bremen 11:
413-421.

1893. Uber Unfruchtbarkeit bei Bestaubung mit eigenem

Pollen. Abh. Nat. Ver. Bremen 12: 409-416.

452 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Fruwirth, C. 1909. Die Ziichtung der landwirtshaftlichen Kultur-
pflanzen 2: 152-156. [Ed. 2.]

Fuchs, H. M. 1915. Studies in the physiology of fertilization. Jour.
Genetics 4: 215-301.

Gardner, V. R. 1913. A preliminary report on the pollination of the
sweet cherry. Oregon Agr. Exp. Sta. Bull. 116.

Goldschmidt, R. 1916. A preliminary report on further experiments
in inheritance and determination of sex. Proc. Nat. Acad. Sci.
2: 53-58.

Goodspeed, T. H. 1915. Parthenogenesis, parthenocarpy and pheno-
spermy in Nicotiana. Univ. California Pub. Bot. 5: 249-272.

Goodspeed, T. H., & Ayres, A. H. 1916. On the partial sterility
of Nicotiana hybrids made with JN. sylvestris as a parent—lII.
Univ. California Pub. Bot. 5: 273 (in press).

Gregory, R. R. 1911. Experiments with Primula sinensis. Jour.
Genetics I: 73-132.

Harris, J. A. 1910. The arithmetic of the product movement of cal-
culating the coefficient of correlation. Am. Nat. 44: 693-699.

Hayes, H. K. 1914. The corn plant and seed selection. Report of
the plant breeder. Ann. Rep. Connecticut Agr. Exp. Sta. 37:
353-384. ;

Hildebrand, F. 1868. Notizen iiber die Geschlechtverhaltnisse brasili-
anischer Pflanzen. Aus einem Briefe von Fritz Miiller. Sta.
Catharina, 12 Sept. 1867. Bot. Zeit. 26: 113-116.

Jeffrey, E. C. 1914. Spore conditions in hybrids and the mutation
hypothesis of de Vries. Bot. Gaz. 58: 322-336.

Jost, L. 1905. Zur Physiologie des Pollens. Ber. Deutsch. Bot. Ges.
23: 504, 505.

—. 1907. Ueber die Selbststerilitat einiger Bliiten. Bot. Zeit.
65: 77-117.

King, H.D. 1916. Experimental inbreeding. Jour. Heredity 7: 70-76.

Kraemer, H. 1914. Effects of inbreeding. Jour. Heredity 5: 226-234.

Kraus, E. J. 1915. The self-sterility problem. Jour. Heredity 6: 549-

--—-

557:

Lewis, C.I., & Vincent, C.C. 1909. Pollination of the apple. Oregon
Agr. Exp. Sta. Bull. 104.

Lidforss,B. 1896. Zur Biologiedes Pollens. Jahrb. Wiss. Bot. 29: 1-38.

Lillie, F. R. 1912. The production of sperm iso-agglutinins by ova.
Science II. 36: 527-530.

——. 19130. Studies of fertilization. V. Jour. Exp. Zool. 14: 515-
574-

——. 1913). The mechanism of fertilization. Science II. 38: 524—-
528.

STOUT: POLLINATIONS IN CICHORIUM INTYBUS 453

———. 1916. The history of the fertilization problem. Science II.
43: 39-53-

Lotsy, J. P. 1913. Hybrides entre espéces d’Antirrhinum. IV®
Conférence Internationale de Génétique 416-428.

Magnus, W. 1908. Weitere Ergebnisse der Serum-Diagnostik fiir die
theoretische und angewandte Botanik. Ber. Deutsch. Bot. Ges.
26a: 532-539.

Magnus, W., & Friedenthal, H. 1906. Ein experimenteller Nachweis
nattirlicher Verwandtschaft bei Pflanzen. Ber. Deutsch. Bot.
Ges. 24: 601-607.

—. 1907a. Uber die Specificitat der Verwandschaftsreaktion der
Pflanzen. Ber. Deutsch. Bot. Ges. 25: 242-247.

—. 1907). Uber der Artspecificitit der Pflanzenzelle. Ber.
Deutsch. Bot. Ges. 25: 337-340.

Martin, J. N. 1913. The physiology of the pollen of Trifolium pratense.
Bot. Gaz. 56: 112-126.

Molisch, H. 1893. Zur physiologie des Pollens. Sitzungsber. Akad.
Wiss. Wien. 102: 423-448.

Morgan, T. H. 1904. Some further experiments on self fertilization
in Ciona. Biol. Bull. 8: 313-330. :

——~. 1910. Cross and self fertilization in Ciona intestinalis.’ Arch.

Entwickelungsmech. Organ. 307: 206-234.

1913. Heredity and sex. Chap. VII.

Miyoshi, M. 1894. Ueber Reizbewegungen der Pollenschlauche.
Flora 78: 76-93.

Muller, F. 1869. Ueber einige Befruchtungserscheinungen. Aus einem
Briefe an F. Hildebrand. Bot. Zeit. 27: 224-226.

Oliver, G. W. i910. New methods of plant breeding. Bur. Pl. Ind.
We: Dept Agr. Bull. 56z.

Osawa, I. 1913. On the development of the pollen grain and embryo
sac of Daphne with special reference to the sterility of Daphne
odora. Jour. Coll. Agr. Imp. Univ. Tokyo 34: 237-264.

Ottenberg, R. i911. Studies in isoagglutination. I. Jour. Exp.
Med. 13: 425-438.

Ottenberg, R., & Friedman, S. S. Studies in isoagglutination. II.
Jour. Exp. Med. 13: 531-535.

Reynolds, E. 1915. Prognosis of sterility. Jour. Am. Med. Asso.
65: II51-1156.

Scott, J. 1865. Observations on the functions and structure of the
reproductive organs in the Primulaceae. Proc. Linn. Soc. Bot. 8:
78-126.

Shaw, H. B. 1916. Self, close and cross fertilization in beets. Mem.
N. Y. Bot. Gard. 6: 149-152. 1916. |

454 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Smith, T., & Reagh, A.L. 1904. The agglutination affinities of related
bacteria parasitic in different hosts. Stud. Rockefeller Inst. 1:
270-300.

Strasburger, E. 1886. Ueber fremdartige Bestaubung. Jahrb. Wiss.
Bot. 17: 50-98.

Swingle, W. T. 1913. Variation in first generation hybrids (imperfect
dominance): its possible explanation through zygotaxis. IV*.
Conférence Internationale de Génétique 381-395.

Tischler, G. 1907. Weitere Untersuchungen tiber Sterilitatsursachen
bei Bastardpflanzen. Ber. Deutsch. Bot. Ges. 25: 376-383.
Tokugawa, Y. 1914. Zur Physiologie des Pollens. Jour. Coll. Sci.

Imp. Univ. Tokyo 35: I-53.

Ulrich, K. 1902. Die Bestéubung und Befruchtung des Rogges. Diss.
Halle.

Vries, H. de. 1910. Intracellular pangenesis. Trans. by C. Stuart
Gager. Open Court Pub. Co.

Waite, M. B. 1895. The pollination of pear flowers. U. S. Dept.
Agr. Div. Veg. Path. Bull. 5.

Wakker, J. H. 18096. Die generative Vermehrung des Zuckerrohrs.
Bot. Centralb. 65: 37-42.

Westgate, J. M., & Coe, H. S. 1915. Red-clover seed production:
pollination studies. U.S. Dept. Agr. Bull. 289.

Wilsdorf, G. 1912. Tierziichtung.

Wilson, J. H. 1906. Infertile hybrids. Rep. 3rd Int. Conference on
Genetics. Roy. Hort. Soc. 183-209.

Zinsser, H. 1914. Infection and resistance.

Explanation of plate 30

Cichorium Intybus
. Head with petals fully expanded; stigmas beginning to protrude.
. Stigmas extended and recurved.
Closed head; about two hours later than fig. 2.
4. As no. I, with petals cut away.

Gym

5. As no, 2, with petals removed, showing pollen masses more plainly.
6 to 11. Individual flowers showing stages in the development of stigma from time
of opening (no. 1) to closing (no. 3) of heads.

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE

STOUT: POLLINATIONS IN CICHORIUM INTYBUS

VARIATION IN TITHYMALOPSIS

J..B.S: Norton
Maryland Agricultural College

In studying the species of Euphorbiaceae around Washington,
D. C., for the District Flora, it became necessary to determine
more carefully the status of the species of 77thymalopsis found
there. TZ. corollata (L.) Klotsch & Garcke and TJ. Ipecacuanhae
(L.) Small, both generally recognized as very variable species, are
very common in this region, and in recent years two others, 7.
arundelana (Bartlett) Small and 7. marylandica (Greene) Small,
intermediate between the other two, have been described and rarely
found.

In analyzing the plants of these species found this year I have
plotted the characters of all the plants seen (over 400) in the
accompanying tabulation which I think will show the relation of
the several species and the relative number of each conspicuous
variation in the total population. I would like to commend to
others the method of analysis of variable species which I have used,
as an easy means of forming a clear picture of the above relations.

The plants studied have not been selected entirely at random,
though mostly so, and the more unusual kinds will appear a little
more frequent in the tabulation than they should by chance.

The progressively subdividing arrangement of the tabulation,
allowing for all possible combinations of the variable characters, is
explained in the following notes: The first column divides the
plants on whether a distinct white appendage is present or not
on the involucral glands. All of typical 7. Ipecacuanhae is in-
cluded in the “appendages none” group, though on almost every
one of the hundreds I have seen, there is a narrow appendage easily
seen with a magnification of 10 diameters. I might also add here
that every specimen of any species of 72thymalopsis which I have
examined has distinct, though minute, stipules.

The second column includes under ‘‘none’’ those forms where
the first cyathium arises from the ground or below. The short-

455

456 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

stemmed are those with the main stem below the inflorescence
less than 6-10 inches long and generally shorter than the mature
umbel. The later flowering begins, the longer the stem.

The third column includes under “‘ pubescence 0”’ plants with-
out hairs outside the involucre or so rare that they cannot be
found without some search. Under ‘‘pubescence —’”’ are those
essentially glabrous, but with hairs easily found on some parts.
The + and + indicate pubescence medium or abundant. The
hairiness seems to vary largely with some external condition,
plants being sometimes glabrous below and hairy above, some-
times the opposite.

The leaf-form column includes under I, leaves broadest below
the middle; under II, leaves broadest at the middle; and under
III, leaves broadest above the middle.

The subdivisions have been carried out further on leaf width,
red color of herbage, width of appendage, length of petiole, angle
of divergence of hairs, length and thickness of peduncle, number
of times the inflorescence branches, etc. It was found, however,
that a number of these characters and others that have been used
in separating species are dependent entirely on the stage of
development. A thorough study of the southern species in both
early and late stages will be necessary before they can be accurately
classified, so I have not included specimens from south of Mary-
land, though I have listed a few western plants for comparison.
Plants of 7. arundelana at the time of first blooming and in mid-
summer would hardly be recognized as the same species.

The amount of red color in stems and leaves, although it varies
somewhat with the environment, is unquestionably largely gov-
erned by hereditary factors.

[ have classified about 200 distinguishable forms but for lack
of space can only show the more easily recognized kinds on the
diagram.

The numbers following each minor subdivision show the num-
ber of plants in the respective group indicated by the associated
letter as follows:

A. Plants from the type locality of T. arundelana.

B. Type of 7. arundelana.

C. Plants with very narrow appendages but broader than the
usual 7. [pecacuanhae type.

NORTON: VARIATION IN TITHYMALOPSIS 457

D. A plant of T. Ipecacuanhae flowering at the same time as
the earliest blooming T. corollata, found at the type station for
T. arundelana.

E. Type of T. marylandica.

F. Plants from two colonies showing relation to T. zinniziflora
Small.

G. Plants from the central U. S. prairie region.

H. Plants from dry, open woods.

J. Plants from northern U. 5.

K. Plants from eastern U. S. not otherwise designated, nearly
all from Maryland.

Seventy-two possible combinations of the variations in presence
and absence of appendages, length of stem, pubescence, and leaf
form are given inthe tabulation. Thirty-three of these were found
in the field. But it will be seen that over one half the plants fall
into 3 or 4 of the ultimate divisions of the scheme.

Though there are 6 groups in the 7. I pecacuanhae series, dis-
tinguished by the practical absence of stem, appendages or hairs,
most of the plants fall into the glabrous form with leaves broadest
above the middle. This might then be taken as the dominant or
typical form of this species in the region under discussion.

No plants have yet been found in the next two series, those
without appendages and with long or short stems.

The T. arundelana series, characterized by acaulescent plants
with white appendages on the glands, has 8 ultimate groups.
There are no very hairy ones and only 2 perfectly smooth plants,
though practically all fall into the essentially glabrous group.
One of the hairless individuals is the single specimen of 7. mary-
landica which I have seen, the plant from Dr. Greene in the New
York Botanical Garden herbarium. I do not know of any one
else other than Dr. Greene who has ever seen this species growing.
It differs further from any of its relatives in Maryland in having
unusually narrow linear leaves. A few plants otherwise similar
to this group and from the type locality of T. arundelana have
short stems and fall into the next series. There is a possibility
that T. arundelana originated as a hybrid between T. Ipecacuanhae
and T. corollata, as all three occur together at the type station in
some abundance and variety and rarely all blooming at the same
time and are also found at every other place where I have dis-

458 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

covered 7. arundelana. There are intermediates in appendage
width and hairiness but as indicated before some of the inter-
mediate series are lacking.

The short-stemmed, appendaged series consists chiefly of a lot
of plants found only in two or three colonies. They tend to have
lanceolate, ovate, or oblong leaves. They are generally broader-
leaved and less hairy than 7. corollata and seem to be nearest
related to T. zinniiflora, some specimens being very close to the
T. zinniiflora type. Some otherwise similar are later-blooming and
longer-stemmed and so included in the next series.

The T. corollata series, characterized by appendages and long
stems, has several rather clearly marked groups. Nearly all the
plants from the central prairie region fall into the group with
hairless stem and leaves. They also have thick, ascending leaves
and tend to be pubescent on the involucre or capsule, thus forming
a rather distinct morphological as well as geographical form.
Nearly all this series are in the four oblong- or oblanceolate-leaved
groups, with more or less pubescence, which may then be considered
the dominant form of the species locally. There is, however, a
marked variation in the open woodland form which tends to be
more hairy and to have oblanceolate leaves.

NORTON: VARIATION IN TITHYMALOPSIS 459
Appendages| Stem length) Pubesence | Leaf form Enumeration ae Total
I UAW CITING ecens ir hu sieteieter ate Steere ee oc | 16
Co) II BUNCE QUINRG eA at cms teks sets seats oo repale | 12
Hl TT AON Ly terete Wailers te BPS, aisha gt iohie's 38
I TLR SP CR Aa acters hoot titer ott succes Tae I
- II 11 GI RE end We Dg rear eh TR I
= Ill AGT PTT Kind Cee nin eft tates 6
2
==
o
S
5 a Sl 8 ees
=
+
1c
°
ii
n
on
=
&
I 1 DAMEN E ee RN ORE S80 I
0) Tica Wh SOR eR RB Cred eta ene eee )
Ill TVA. Meine acuennte Rava etn chao SENN I
I GACT Ss oor etek ot ten cueveta teceghors 7
y a Hye IG ArS #0. Sudeep en aa oe eb tome 8
2 Die Wickhn tC tne eet ace, oth, eee 5
5 I TU a Re nae Os ig he Pee ee eS A 4
eS I yO Sn, ERS aed ee eR St I
oer ear See Ne TE 2
+
fo)
I (C) Spee Mencia, cara tee pare Su RCAC 9
as oF = II AUS Ua setae ete tere nasacort 15
[ 5 Ill 0 Mee Ree oe MER cy cece paecO tec Uc eedo I
g a Te car st lap are ae eee asta er ge 12
o 25 II RA PSB Hema p tein se ane ene 8
Ill TA dee bs shi eects tea enema aa I
I ae eg ee REO ee: egies of g)
aI OTe es lees et Os SES a ene ee epee ed eo oO
TAIT pst ces ee Ns Swe ge Ree eset amet ae ok fe)
I DB (Si eaarcpien a Se he eee heen od Mean a reir 2
oO II SOG e so chat Seer trae can ct Re ete aber es 9
Ill St aOR Se RARE Eh oat cog SOP gL a
I tA Gy, SUG eran de ome reas 8
ae Il BA AGH TE) PSRs 2. am apie ecta eer 25
30 Wl Berg Crees Mc Wan Al Oe mAh ye etna is Ate 15
BS) I SAR BE DG esctae «calcite ole penebaia sere 26
35 II DOs LG kL pays eae ne creasee snes or 80
III SAN, Gt dl, Tp OOUS Ses aaron =.=) ste 69
I Ry eerie Sc set Sar eed ot Stake yates a iat 3
+ II Ti) NCC) i eat) 5 GA pe are Aang 16
Ill iR/AN el 5 fe. WERE Soe eieptne ave Cony RS rue 9

THE GENUS HIPPOCHAETE IN NORTH AMERICA,
NORTH OF MEXICO

OLIVER ATKINS FARWELL

Parke, Davis and Company, Detroit

My attention was specifically drawn to these plants through
the monograph of the genus Equisetum by Mr. A. A. Eaton, which
appeared serially in the Fern Bulletin, and in which the exclusion of
E. laevigatum and E. robustum from Michigan was so opposed to
my field studies of these species, as I understood them, that I
concluded to give the subject further and more careful attention
in order to confirm my earlier views or to reject them. Mr. Eaton,
it is true, credited E. robustum to Sarnia, Michigan, but Sarnia is
in Ontario, Canada. These two species are unquestionably found
in Michigan.

The following notes are based primarily on field studies, supple-
mented by studies of material distributed by Eaton and of that
in the herbarium of Parke, Davis & Co.

Mr. Eaton said there were no true varieties, with perhaps the
exception of E. arvense var. boreale, in the genus Eguisetum; and
then listed a large number, many of them new, but specifically
made no claims for their constancy. A goodly number of these
so-called varieties are based entirely on an injury to the individual
plant, and therefore are no more deserving from a systematic
point of view, of a special name and the dignity which is always
conferred by the elevation of a form to one of the named nomen-
clatorial categories, than is, in the higher plants, a willow stump
that has sent out innumerable branches to prolong its existence;
or if it pleases you to have the subject matter brought a little
nearer home, than is a man with an artificial limb to be ranked
as a new species in the genus Homo. All these so-called varieties
may be produced at will from the same evergreen stalk. The
apex of a normal evergreen stem may be broken off and labeled
under its specific name; the following year another section, now
with long branches, may be broken off and labeled var. ramigerum;

461

462 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN -

the next year what is left of the stem may be bearing the short
spiciform branches of the var. ramosum; and the next season will
see numerous stems surrounding the base of the old one, whence
we have the var. caespitosum. To apply names of specific or other
rank to such forms is the climax of folly. On the other hand,
when a species is normally unbranched, if a form of it is found
that constantly produces branches naturally, i. e., not due to an
injury, such a form is a normal variety; such a form can not be
found on the same rhizome with another of different character,
while all the so-called varieties due to an injury may be found
along with the normal stem emanating from the same rhizome
and sometimes two or more such forms may be found on the
same crown! I have observed several forms due to an injury,
that do not come within the description of any variety enumerated
by Mr. Eaton; but they are as much deserving of recognition as
any such that he has named.

With special reference to the bast and green parenchyma,
there are two very distinct types of anatomy in the genus Hip-
pochaete: one with abundant vallecular bast completely cutting
the green parenchyma while the carinal bast is slight and
does not completely cut the parenchyma, thus dividing it
into Y-shaped blocks; the other is just the reverse of this, the
vallecular bast, being of small amount, does not divide the paren-
chyma, while the carinal is plentiful and does divide it, or nearly
so, thus splitting the green parenchyma into blocks shaped some-
what like a carpenter’s drawing knife H. laevigata best ex-
emplifies the former, while H. prealta is typical of the latter.
Similar to H. laevigata are H. variegata and H. hyemalis var.
alaskana. Like H. prealta are H. prealta var. affinis, H. hyemalis
var. californica, H. scirpoides, and the European H. hyemalts.
The other species and varieties are either intermediate in char-
acter or they combine both types in greater or less degree. In
the intermediate forms the parenchyma is continuous under both
the vallecular and carinal basts, the outer surface being even, or
more or less indented but not divided by the basts. When the
two types are combined the Y-shaped parenchyma may alternate
with the other type, or the parenchyma may be divided by
both the vallecular and carinal basts splitting it up into irregularly
triangular b!ocks. The central cavity is also variable, ranging

FARWELL: GENUS HIPPOCHAETE IN NORTH AMERICA 463

form obsoleteness in H. scirpoides to 4/5 the total diameter of the
stem in H. prealta and H. laevigata. It has been suggested that
all variations from the two types above mentioned, in the anatomy
of some forms, are due to hybridization. This may be so but it
has. yet to be proved by exact laboratory work. On the other
hand, varieties combining these intermediate or variable anatomi-
cal characters, such as H. variegata var. anceps and H. hyemalis
var. Jesupi are sometimes found where the supposed parents
have never been detected; the former on Parkedale Farm and
the latter on Belle Isle, an island in the Detroit River, which
has 5 or 6 miles of shore line with the nearest point of mainland
1/2 a mile away. It is the only Hippochaete that has ever been
detected on the island.

In certain Californian plants Mr. Eaton ascribes to Hippochaete
ramosissima (Desf.) comb. nov. (Equisetum ramosissimum Desf.
Fl. Atl. 2: 398. 1800) an anatomy like that of H. laevigata.
According to Luerssen the parenchyma of this species is continuous
thus being intermediate but more similar to that of Hippochaete
hyemalis (L.) comb. nov. (Equisetum hyemale L. Sp. Pl. 1062.
1753) than to H. laevigata. If Luerssen is correct in regard to
the anatomy of H. ramosissima, then the Californian plants are
not of that species and it should be excluded from the American
flora. Notwithstanding that Sadebeck gives it a range on the
American continents from 49° north latitude to 30° south latitude,
it is highly improbable that it occurs north of central Mexico.
Judging from the anatomy, as described by Mr. Eaton, the plants
he referred to H. ramosissima should be referred to some form
of H. laevigata, probably to var. Funstont.

From an intimate study of these plants in the field, extending
over many years, I have become thoroughly imbued with the
conviction that they constitute a valid genus distinct from Equi-
setum. The habit and other characters by which Hzippochaete
differs from Equisetum are as constant and of as much significance
as those which separate Aster from Solidago in the higher plants,
and many other closely allied genera which could just as readily
be named. Generally speaking their differences may thus be
expressed.

Stems annual, often dimorphous, the sterile always with regular verticils

of acutely angled branches at the nodes; spikes rounded at apex;
stomata scattered. EQUISETUM.

464 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Stems generally evergreen, not dimorphous, usually simple; branches
when present, similar to the stem; spikes usually apiculate; stomata
in regular rows. H1IpPOCHAETE.

Of the genus Egquisetum (Tourn.) L., the type species is E£.
arvense; of Hippochaete Milde, H. hyemalis. I have not been
able to verify Milde’s authorship of the genus but according to
Ascherson and Graebner, Milde published it in the Botanische
Zeitung for 1865, p. 297. The genus is readily subdivided into
two sections. The species with evergreen stems and apiculate
spikes form a group that may be known as section EUHIPPOCHAETE;
those with annual stems and generally obtuse spikes may be known
as section AMBIGUA.

The chief character separating the sections is the duration of
the stem; those separating the species are to be found in the
ridges and sheaths, whether concave and biangulate, or convex
and banded, campanulate or cylindrical. Following out these
lines of differentiation, the species will be assembled in a more
natural grouping than by any other method.

Key to the species

Stems evergreen, spikes apiculate (EUHIPPOCHAETE).
Ridges concave, biangulate.
Ridges narrowly concave, numerous.
Sheaths cylindrical, tight.
Centrum 3/4 the diameter of the stem,
teeth deciduous or more or less

persistent. H. hyemalis var. californica.
Centrum, 1/2 the diameter of the stem;

teeth and awns persistent. H. hyemalis var. Jesupi.
Centrum 1/3 the diameter of the stem;

awns deciduous. HH, hyemalis var. alaskana.

Sheaths campanulate, loose.
Centrum 1/3 the diameter of the stem;

teeth persistent, awns deciduous. Hf. variegata.
Centrum 1/6 the diameter of the stem
to obsoleteness. HH. variegata var. anceps.
Ridges broadly and deeply concave, these and
the teeth three. H. scirpoides.

Ridges rounded, not biangulate.
Sheaths cylindrical, tight.
Stems simple.
Sheaths broader than long, teeth per-
sistent. H. prealta.
Sheaths longer than broad, teeth cadu-
cous, HH, prealta var. affinis.

FARWELL: GENUS HIPPOCHAETE IN NORTH AMERICA 465

Stems normally branched; branches spike
bearing. Hi. prealta var. Suksdorfi.
Sheaths more or less ampliate and loose, but
not campanulate.

Teeth caducous. H. prealta var. intermedia.
Teeth deciduous or persistent. H. prealta var. scabrella.
Stems annual, spikes obtuse or apiculate, ridges rounded
(AMBIGUA).
Sheaths cylindrical, tight; teeth persistent. H. Nelsoni.
Sheaths campanulate and loose; teeth caducous.
Stems smooth to the touch. H. laevigata.
Stems rough, simple.
Bases of teeth straight. H. laevigata var. Eatonit.
Bases of teeth, incurved. H. laevigata var. Funstoni,
Stem rough, branched. H. laevigata var. polystachya.

HIPPOCHAETE HYEMALIS var. californica (Milde) comb. nov.

Equisetum hyemale var. californicum Milde; A. A. Eaton, Fern

Bull. 11: 113. 1903, as to the biangulate plants only.

Equisetum hiemale var. Doellit Milde; A. A. Eaton, Fern Bull.

ll; a04. 1903... Not Milde, 1863.

Typical H. hyemalis with caducous teeth has never been col-
lected in America. The Pacific coast plants differ in having the
teeth deciduous or more or less persistent. The plants referred
by Mr. Eaton to the var. Doellit Milde cannot belong there as that
European variety has the centrum only one fourth or one third
the diameter of the stem, while the British Columbia plants have
a centrum four fifths the diameter of the stem and the teeth are
not wholly persistent as described, at least on specimens distri-
buted which show them to be generally deciduous. California to
British Columbia.

HIPPOCHAETE HYEMALIS var. Jesupi (A. A. Eaton) comb. nov.

Equisetum variegatum var. Jesupt A. A. Eaton, Fern Bull. 12:
24. 1904.

This variety has some of the characters of H. variegata, towards
which it trends. The teeth have long, generally persistent awns
and the anatomy is variable, sometimes of one type, sometimes
of the other. The size and aspect are intermediate but the tight,
cylindrical sheaths place it with H. hyemalis rather than with
H. variegata.

Belle Isle, Mich., Farwell 211a, June 4, 1895; Rochester, Mich.,
Farwell 211b July 4, 1896. Mr. C. K. Dodge has collected it
at Port Huron, Mich. Its general distribution is from Illinois
to Connecticut, northward into Canada.

466 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN ~—

H1ipPOCHAETE HYEMALIS var. alaskana (A. A. Eaton) comb. nov.

Equisetum variegatum var. alaskanum A. A. Eaton, Fern Bull.
P2339: 1904.

Somewhat similar to the last variety but larger, yet with a
relatively smaller centrum, awns deciduous, and anatomy much
like that of H. variegata. The cylindrical, tight sheaths place it
here rather than with the species just named. In dried plants the
sheaths are liable to be slightly ampliated. Washington to
Alaska.

Hippochaete variegata (Schleich.) comb. nov.

Equisetum variegatum Schleich. Cat. Helvet. 27. 1807.

This species, in its typical form, is common on sandy or gravelly
shores on the Keweenaw Peninsula, a tongue of land 60 miles in
length, stretching northeasterly into Lake Superior. It is associ-
ated with H. laevigata and Equisetum limosum. I have seen no
indications that either this or the variety anceps is injured by
frost in this state and they are certainly evergreen.

Keweenaw Peninsula, Mich., Farwell 211, May 30, 1885. This
species may be looked for north of 42°. It prefers the borders
of cold streams and ponds.

HIPPOCHAETE VARIEGATA var. anceps (Milde) comb. nov.

Equisetum variegatum var. anceps Milde, Ann. Mus. Lugd. Bat.
Le Ese She:

This variety is intermediate in aspect between the species and
H. scirpoides and approaches the latter in habit. The stems are
evergreen 30 cm. or less in height by 1 mm. or less in diameter
and are massed in a mat-like growth. The centrum is from obso-
lete to one sixth the diameter of the stem and does not exceed the

vallecular cavity; the anatomy is variable. The ridges and leaves

are 4-8, the teeth persistent,and theawns deciduous. Thebranches
have the same number of ridges and leaves as the stems or fewer
and in some instances they have five leaves while the stem has
four; the only instance, so far as | am aware, where a branch
has more ridges and leaves than the stem from which it springs.
It grows on grassy borders of marl under willow thickets associ-
ated with moss and sedges. Parkedale Farm, Mich., Farwell 2921,
July 28, 1912.

FARWELL: GENUS HIPPOCHAETE IN NORTH AMERICA 467

Hippochaete scirpoides (Michx.) comb. nov.

Equisetum scirpoides Michx. Fl. Bor.-Am. 2: 281. 1803.

Our smallest species, forming dense mats along old logs and
stumps in open fields, cedar swamps, etc. Well characterized by
its three leaves and ridges, the latter so deeply and broadly con-
cave that the stem apparently is 6-ridged.

Keweenaw Peninsula, Mich., Farwell 212, May 30, 1885. This
has much the same range as H. variegata but extends about 2°
further south.

Hippochaete prealta (Raf.) comb. nov.
Equisetum prealtum Raf. Fl. Ludovic. 13. 1817.
Equisetum robustum A. Br. Am. Jour. Sci. 46, 88. 1843.
Equisetum robustum var. minus Engelm. in A. Br. Am. Jour.
Del 46,05. 1342.

Equisetum hyemale var. Drummondi Milde, Mon. Equit. 593.
1865 (?).

Equisetum hiemale var. robustum A. A. Eaton, Fern Bull. 11:
Las O03.

Equisetum hiemale var. californicum Milde; A..A. Eaton, Fern
Bull. 11: 113. 1903, as to the plants with rounded ridges.
Equisetum hyemale var. prealtum (Raf.) Clute, Fern Bull. 16: 18.

1908.

This is our largest and most widely spread species and probably
our most common one. It is well characterized by its cylindrical,
tight sheaths, which are as broad as long or sometimes a little
broader or narrower than long, its persistent teeth, and very
‘numerous, rounded ridges. It may be found on sand banks, in
poor soil, in swamps and bogs; generally near water. Mr. C. K.
Dodge has collected it near Port Huron, Mich., and near Sarnia,
Ontario.

Keweenaw Peninsula, Mich., Farwell 209%, May 30, 1885; 572,
Aug. 29, 1887. Rochester, Mich., Farwell 2075, Aug. 4, 1912;
3696 and 3710, June 28, 1914; 3722, July 19, 1914; 3922 and
3927, October 25, 1914. Parkedale Farm, Mich., Farwell
398814, June 20, 1915. May be found from the Atlantic to
the Pacific but rare east of the Mississippi basin.

HIPPOCHAETE PREALTA var. affinis (Engelm.) comb. nov.
Equisetum robustum var. affine Engelm. in A. Br. Am. Jour.
Sci. 46: 88. 1843.

468 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Equisetum hiemale var. pumilum A. A. Eaton, Fern. Bull. 11:
109. 1903.

Equisetum hiemale var. affine (Engelm.) A. A. Eaton, Fern.
Bull. 11: 111. 1903.

Differs from the species in its longer sheaths which are 1/3-2
times as long as broad, and in the teeth, which are caducous.
Where this variety and the species overlap they intergrade and
pass insensibly one into the other, indicating that there is but one
species, although the extremes seem distinct enough.

Keweenaw Peninsula, Mich., Farwell 200, May 30, 1885. Palmer
Park, Mich., Farwell 209a, July 15, 1902. Rochester, Mich.,
Farwell 3604 and 3605, June 28, 1914; 3925, 3926, October 25,
1914; 3929%, October 29, 1914. Parkedale Farm, Mich.,
Farwell 3922 1%, October 25, 1914; 3908414, June 20, 1915. From
the Atlantic to the Pacific but most common east of the Missis-
sippi River.

HIPPOCHAETE PREALTA var. Suksdorfi (A. A. Eaton) comb. nov.
Equisetum hiemale vat. Suksdorfi A. A. Eaton, Fern. Bull. 11:

I1O. 1903.

Somewhat similar to the variety affinis but has whorled branches
from the upper nodes, which are spike-bearing simultaneously
with the central stem; Mr. Eaton described it as with the anatomy
of E. hiemale but material distributed by him shows the green
parenchyma cut by the vallecular bast which, with the branching
habit, indicates a tendency toward H. laevigata, while the rosulae
in the groove show a trend toward H. hyemalis var. californica.
Collected by W. N. Suksdorf, September 3, 1902, at Bingen,
Washington.

HIPPOCHAETE PREALTA var. intermedia (A. A. Eaton) n. comb.
Equisetum hiemale var. intermedium A. A. Eaton, Fern. Bull.
10: 120. 1902, pp., and in Gray’s New Manual, 53. 1908.
The sheaths are ampliated but not campanulate, and the teeth
are caducous. Described by Mr. Eaton as with the anatomy of
Equisetum hiemale but material distributed by him shows a variable
anatomy, sometimes that of H. prealia sometimes that of H.
laevigata. Collected at Port Huron, Michigan, by Mr. C. K.
Dodge. It has been found in various localities from the Atlantic
to the Pacific and may be looked for whenever H. laevigata and
H. prealta var. affinis may be found in close association.

FARWELL: GENUS. HIPPOCHAETE IN NORTH AMERICA 469

HIPPOCHAETE PREALTA var. scabrella (Engelm.?) comb. nov.

? Equisetum laevigatum var. scabrellum Engelm. in A. Be. Am.
Jour. Sci. 46: 87. 1843.
? Equisetum hiemale var. texanum Milde; A. A. Eaton, Fern
- Bull. 11: -708:. 1903.

Similar to the preceding variety but the sheaths are propor-
tionably broader and the teeth deciduous or persistent, indicating
a cross between H. laevigata and H. prealta, if these intermediate
forms are to be considered as the result of hybridization. I do
not know if this is Engelmann’s variety or not but it agrees in
every particular with Eaton's description of Equisetum laevigatum
var. scabrellum in Fern. Bull. 11: 42. 1903. The stems of the
season have the general aspect that H. laevigatum would have if
its sheaths had persistent teeth; the stems of the preceding year
have the general markings of H. prealia. The anatomy is now
of the one species, now of the other.

Rochester, Mich., Farwell 37121, July 4, 1914.

Hippochaete laevigata (A. Br.) comb. nov.

Equisetum laevigatum A. Br. Am. Jour. Sci. 46:87. 1843.

This species in its typical form is well characterized by its
simple or branched, annual, stems, which are smooth, at least to
the touch, its rounded spikes, and campanulate sheaths with
caducous teeth. Those varieties which are intermediate between
this and other species generally will have rough stems and spikes
that are either obtuse or apiculate. It may be found in clear
sand or gravel, or a similar soil covered with a sparse growth of
grass and other vegetation and generally not far from water.

It may be found in colonies by itself, or it may be associated
with H. prealta and its variety affinis, H. variegata, and Equisetum
limosum. The vallecular bast divides the green parenchyma into
y-shaped divisions. Eaton restricted this species east of the
Mississippi to Ohio, Indiana, Illinois, and Wisconsin; but I have
found it in southeastern Michigan, where it is common, and on
the Keweenaw Peninsula, where it cannot be said to be scarce.
Probably it is to be found throughout the state. The annual
stems begin their growth about the first of May, are fruiting in
June, and perish in July or August. New stems are appearing
continuously until the middle of the summer but all have perished

470 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

before winter has set in. It may be noted here that growth in

the evergreen species begins, in Michigan, about the middle of

May and continues through the summer.

Keweenaw Peninsula, Mich., Farwell 39004%, June 29, I915-
Algonac, Mich., Farwell 3640, 36841%, 3685, June 21, 1914.
Detroit, Mich., Farwell 210e, June 24, 1902. Rochester, Mich.,
Farwell 210c, July 4, 1896; 3721%, July 19, 1914. Stony
Creek, Mich., Farwell 343814, June 8, 1913. Parkedale Farm,
Mich., Farwell 2701, June 11, 1912; 3677%, June I1, 1914;
3705, June 28, 1914. Common west of the Mississippi and in
the ‘Lake States.”

HIPPOCHAETE LAEVIGATA var. Eatonii var. nov.

Equisetum hiemale var. intermedium A. A. Eaton, Fern. Bull.
10: 120. 1902, as to the annual plant.

Externally, this variety can be distinguished from the typical
species only by the roughness of the stem and the occasionally
apiculate spikes. The anatomy is very variable, sometimes that
of the species, sometimes that of H. prealta var. affinis; now inter-
mediate when the parenchyma is continuous, and now combining
both types when both the carinal and vallecular basts divide the
green parenchyma, splitting it into irregularly triangular blocks.
It may be found alone, associated with H. laevigata, H. prealta,
or its var. affinis, or with all of these. In the original description
of Equisetum hiemale var. intermedium, Eaton included annual
and evergreen plants with teeth that were caducous, deciduous,
and persistent. In the seventh edition of Gray’s Manual he had
restricted the variety to the evergreen plant with caducous teeth.
This left the evergreen plant with broader sheaths and persistent
teeth and the annual plant with caducous teeth without names.
For the former I have adopted Engelmann’s varietal name of
scabrella; to the latter I give the varietal name Eatonii.. The
first stems of the season fruit in June and perish in July and
August when the later stems are fruiting and others just coming up.
At this time it simulates H. prealta var. intermedia but is quickly
and readily differentiated by its annual stems, which have not the
bright green of that variety. Some plants have completely
perished before winter sets in while others in greater or less degree
survive the winter but these parts have perished before the new

FARWELL: GENUS HIPPOCHAETE IN NORTH AMERICA 471

erowth of the season begins in May. Where this variety grows

in profusion it is not an uncommon thing to see in March, just

after the snow has disappeared, its long stems chalk-white and
intact lying flat upon the ground, crossed in all directions. When
disturbed, however, they will fall apart and crumble into powder.

The stems like those of the species may be single or caespitose,

simple or branched, and often four feet in height. I have not

seen any with spike-bearing branches.

Wiards Siding, Mich., Farwell 2159/4, 215014, June 25, 1910.
Rochester, Mich., Farwell 27061, 2710), June “Lr,” 1912;
3643 %, May 26, 1914; 3604, June 8, 1914. Algonac, Mich.,
Farwell 3640a, July 26, 1914.

HrppocHAETE LAEVIGATA var. Funstoni (A. A. Eaton) comb. nov.
Equisetum Funstoni A. A. Eaton, Pera. Bull. 1): 10-12.5 1993
(excluding forma polystachyum).

Equisetum laevigatum f. variegatoides A. A. Eaton, Fern Bull. 11:
AZ. 1903:

? Equisetum hiemale var. herbaceum A. A. Eaton, Pern, Bull:
11: 10a9. 1903-

Similar to the specific type but very rough and the bases of
the caducous teeth are more strongly incurved. Eaton described
the spikes of E. Funstoni as “not apiculate as in the rest of the sub-
genus.” H. laevigata has non-apiculate, i. e., rounded, spikes and
E. Funstoni as distributed by Eaton has some of the spikes apicu-
late. The parenchyma is sometimes divided by the vallecular
bast, sometimes not. Eguisetum laevigatum f. variegatoides and
Equisetum Funstoni {. caespitosum as distributed by Eaton are to
be differentiated by only one character; the stems of the former
are prostate, ascending, or erect, while those of the latter are
ascending or erect—a distinction without a difference. Both have
prominently white-bordered teeth fading to white throughout.
There seems therefore to be no good reason for keeping Funstont
separate from Jaevigata. It has been collected in Wisconsin,
Nebraska, Kansas, Wyoming, Utah, and California.

HipPpoOCHAETE LAEVIGATA var. polystachya (A. A. Eaton) comb.
nov.
Equisetum Funstoni {. polystachyum A. A. Eaton, Fern Bull.
Th i2.)) (EGU: |

472 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN .

Equisetum laevigatum f. polystachyum A. A. Eaton, Fern Bull.
I1: 44. 1903.
A form in which the stem and its branches (not due to an injury)
are simultaneously spike-bearing.

Hippochaete Nelsoni (A. A. Eaton) comb. nov.
Equisetum variegatum var. Nelsoni A. A. Eaton, Fern. Bull. 12:
41. 1904.

Intermediate between H. laevigata and H. hyemalis var. Jesupi
but more like the latter in appearance than the former. The
rounded ridges and annual stems, however, place it more appro-
priately in the section Ambigua than in the Euhippochaete. The
parenchyma is frequently divided by the vallecular bast but not
regularly so. The sheaths in dried plants are liable to be slightly
ampliated. It has been collected in New York, Michigan, and
Illinois.

A FOSSIL FERN MONSTROSITY

ARTHUR HOLLICK

Staten Island Association of Arts and Sciences
(WITH PLATES 3I AND 32)

A short time ago I received from Dr. F. H. Knowlton of the
United States National Museum a number of specimens, appar-
ently representing fragments of a fossil fern, which are unlike any
fossil fern remains heretofore described or figured, so far as I am
aware. Superficially nearly every specimen presents the appear-
ance of a sport or monstrosity, strikingly similar to some of those
which have been developed in cultivated forms of the Boston
fern, Nephrolepis exaltata (L.) Schott. On PLATE 31 are figures
of three of the specimens, reproduced natural size, and on PLATE 32
are two photographs of portions of fronds of NV. exaltata, recently
selected for purposes of comparison from plants growing in the
conservatory of the Brooklyn Botanic Garden.

If the specimens represent a species, it was a unique and peculiar
one. If, on the other hand, they represent a freak or monstrosity,
this is equally remarkable. In any event it is apparently a fern,
and the probability is that it belongs in a living genus; but the
critical characters are too imperfectly preserved for satisfactory
comparison. Nevertheless, the species, or variety, or form, which-
ever it may be, is certainly of sufficient interest to be figured and
to be described as accurately as possible, even if with no other
result than to invite criticism.

The preservation of plants as fossils is and always must have
been a matter of fortuitous conditions. The number of specimens
thus preserved during any period in the earth’s history must
represent merely a very small fraction of the vast host that lived
and died during the same period and left no trace behind. We
may, therefore, assume that a rare or local species, represented
by a relatively small number of individual plants or confined to a
limited region, would have had but little chance of being preserved

473

474 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

in the fossil condition; and a sport or monstrosity, confined pre-
sumably to a small group of individuals or perhaps to a single
one, would have had a yet smaller chance. On general con-
siderations, therefore, it would seem most consistent to regard
our specimens as representing a species, and to apply a generic
name that will indicate merely a probable relationship with the
ferns.
Anomalofilicites monstrosus gen. et sp. nov.

Size and shape of frond not known, the parts irregularly pinnate;
pinnae diverse in shape and size, mostly pinnatifid or obscurely
pinnate, linear-lanceolate in outline and tapering to the tips, but
occasionally expanded and pinnate except toward the base, the
pinnules pinnatifid.

Tertiary (Fort Union Formation), Kern Ranch, Dawson County,
Montana. Collected by A. G. Leonard, George Holgate, and
W. H. Clark, September 28, 1906.

Those who may be interested in the line of investigation sug-
gested by the peculiar surficial characters of these specimens will
find the following works of assistance: .

E. J. Lowe, Our native ferns, etc., vols. 1 and 2. London,
1867, 1869.

Robert G. Leavitt, A vegetative mutant and the principle of
homeosis in plants. Bot. Gaz. 47: 30-68. f. 1-19. Ja, 1909.

R. C. Benedict, Some modern varieties of the Boston. fern at
their source. Jour. N. Y. Bot. Gard. 16: 194-197. pl. 161, 162.
SrOLs:

Explanation of plates 31 and 32

PLATE 31. Anomalofilicites monstrosus Hollick, natural size. 1 from U. S. Nat.
Mus. no. 34987; 2 from U.S. Nat. Mus. no. 34988; 3 from U.S. Nat. Mus. no. 34986.

PLATE 32. Nephrolepis exaltata (L.) Schott. Portions of heteromorphous fronds
from living plants growing in conservatory of the Brooklyn Botanic Garden, natural
size.

Mem. N. Y. Bor. GARDEN VOLUME VI, PLATE 31

AXNOMALOFILICITES MONSTROSUS Hollick

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 32

HETEROMORPHOUS FRONDS OF NEPHROLEPIS EXALTATA (L.) Schott

RECENT EXPLORATION IN SOUTHERN FLORIDA!

Joun K. SMALL
The New York Botanical Garden

Previous to 1903, when we began botanical exploration in
southern Florida, the country southwest of Cutler and Perrine,
then the frontier settlements on the eastern coast of Florida, was
almost a terra incognita. A wagon road to the south of Miami,
or Fort Dallas, as it was at one time called, connected that place
with Cocoanut Grove and Cutler and terminated at Perrine, which
was an old but scarcely at all developed settlement in the pine
forest, situated about three miles west of Cutler and Bay Biscayne.
Near Perrine the surveyor’s trail entered the pine forest and
extended toward the southwest through the unbroken wilderness
until it met the open Everglades at a point called Camp Longview.
Later, another trail developed parallel to the proposed railroad
route to Cape Sable and met the Everglades between three and
four miles south of Camp Longview.

Notwithstanding the inaccessibility of this region during the
early period of exploration, except by the trails just referred to,
we found scores of plants, either new to science or typically West
Indian and Central American, not before known to occur naturally
in the United States, not even on the tropical Florida Keys, and
learned that these islands in the Everglades which we have de-
signated the Everglade Keys are, so far as their vegetation is
concerned, a portion of the West Indies isolated on the Florida
peninsula.

The following table will indicate the geographical extent of our
recent operations and the character of the points visited.

EVERGLADE KEyYs Brickell (twice)
Pineland hammocks and ad- Brogdon
jacent pinelands, Miami Cocoanut Grove
and southwestward Costello (thrice)
Addison Cox
Black Point Creek (twice) Goodburn (twice)

1Abstract. For a more extended report, see Jour. N. Y. Bot. Gard. 17: 37-45. pl.
166-168. 1916.
475

476 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Hattie Bauer (thrice) Vic. Long Prairie

Murden Vic. Murden hammock

Nelson Vic. Nixon-Lewis ham-

Nixon-Lewis (thrice) mock

Ross (thrice) Vic. Timms hammock

Royal Palm (twice) Vic. Silver Palm

Shields Vic. Larkins

Snapper Creek

Sykes (thrice) SAND-DUNES

Timms (twice) Near Crocodile Hole

Opp. Lemon City
EVERGLADES Opp. Miami (twice)
Prairie hammocks north of Key Biscayne
Miami

Freeman (twice) FLoRIDA Krys

Merritt’s Island Sands’ Key

Humbugus (twice) Old Rhodes’ Key
Prairies north of Miami. Caesar’s Rock

Humbugus (twice) Adams’ Key

Little River Pumpkin Key

Arch Creek Elliott’s Key
Prairies south of Miamz. Big Pine Key

Cutler to Black Point Key West

These comprise distinct phytogeographical areas. They are as
follows:

Everglade keys—Pineland hammocks and adjacent pinelands.

Everglades—Prairie hammocks and prairies.

Coastal Sand-dunes—Hammocks.

Florida Keys—Hammocks and pinelands.

A brief summary of the more interesting discoveries in the col-
lection of about 11,000 specimens, so far as studied, is as follows:
First, over forty species of flowering plants comprising naturalized
exotics and heretofore unobserved natives, added to the known
flora of the Everglade Keys and vicinity. Second, additions to
the known flora of the United States: Mushrooms, two West
Indian species and several new endemic species; liverworts, four
West Indian species and three new species; mosses, several West
Indian species; ferns, a West Indian species; flowering plants, ten
West Indian species and several new endemic species.

VEGETATIVE LIFE ZONES OF THE ROCKY
MOUNTAIN REGION

P. A. RYDBERG
The New York Botanical Garden

It was twenty years ago last June that I had my first intro-
duction to the flora of the Rocky Mountains proper. Even
before that time I had spent three summers in the foothills in
western Nebraska and in the Black Hills of South Dakota. While
being principally occupied in a botanical survey from a taxonomic
standpoint, during the eleven summers spent in the Rocky Moun-
tain region, I could not help making some observations on the
general phytogeography of the country. As very little has been pub-
lished on this subject, and as some of that little is quite misleading, I
thought it advisable to place on record these observations of mine,
however incomplete they may be. They were made rather inci-
dentally, and could not be otherwise. I therefore began publishing
in the Bulletin of the Torrey Botanical Club aseries of articles under
the heading ‘‘ Phytogeographical notes on the Rocky Mountain
region.’’ The present paper should in reality have been the
first of these articles as an introduction to the more specialized
topics already begun.

The Rockies extend from the neighborhood of Santa Fé, New
Mexico (about Lat. 35° 30’), to near Lat. 65° in the Yukon Terri-
tory, and the different parts must show great variations in the
flora. The flora of the region north of Lat. 55° is practically
unknown to me, and that of the Canadian Rockies south of 55°
I know only from the collections made by others, but such are
well represented in the herbarium of the New York Botanical
Garden, as the Geological Survey of Canada has let us have the
first set of their duplicates for years.

As I have already pointed out in one of my articles printed
last January, the Rockies south of Lat. 55° can be divided into
two parts: The Southern Rockies from the Santa Fé Mountains
in New Mexico to the Medicine Bow Mountains in southern

477

478 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Wyoming; and the Northern Rockies from the Wind River
Mountains in central Wyoming northward. To the former may
be ascribed also the Uintah, Wasatch, and several other smaller
ranges in Utah. As belonging to the floral district of the Northern
Rockies are to be counted several more or less isolated mountains
in Idaho, Montana, and Wyoming. The Cypress Hills in Sas-
katchewan and the Black Hills of South Dakota and Wyoming
may also be included therein, though both contain many eastern
elements.

The division between Northern and Southern Rockies is not
made wholly because there is a break in the high mountain chain,
about where the Union Pacific Railroad crosses Wyoming, but
because many plants are restricted to either region and do not
cross the gap. The floras of the two regions show many differ-
ences, especially is this the case of the more characteristic species
of the wooded areas. It is true that many of the trees, as Picea
Engelmannit, Pinus scopulorum, P. Murrayana, and P. flexilis,
Pseudotsuga mucronata, Abies lasiocarpa, Sabina scopulorum,
Betula fontinalis, Alnus tenuifolia, and several species of Crataegus,
Salix, and Populus are common to both regions, but others are
not. Pinus aristata, P. edulis and P. monophylla, Picea Parryana,
Sabina monosperma and S. utahensts, Populus Wislizent and P. Fre-
monti, Fraxinus anomala and the oaks of the Quercus Gambelii and
Quercus undulata groups are practically restricted to the southern
Rockies. Of these only Picea Parryana has been collected in
what I consider as belonging to the Northern Rockies, namely
in the Teton Mountains of western Wyoming. It is between
these mountains and the Bear River Mountains of southern
Idaho (an extension of the Wasatch), not along the continental
divide in central Wyoming, that an interchange of species
between the two regions takes place. Hence some northern
species are found in southern Idaho and northern Utah, but not
in southern Wyoming, and a few southern ones in the Tetons.

The wooded flora of the Sierra Madre shows stili more striking
differences, but this would lead us outside the present discussion.

In the Rocky Mountains proper I am inclined to recognize the
following zones: (1) Alpine; (2) Subalpine; (3) Montane; (4) Sub-
montane or Foothills; (5) Upper Sonoran. These correspond
practically to Dr. Merriam’s life zones: Arctic, Hudsonian,

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 479

Canadian, Transition, and Upper Sonoran. I have preferred the
names given above rather than those of Merriam, because the
former have been used by many authors in Europe in articles on
the phytogeography of the Alps and other mountain regions.
Furthermore, I do not like the names Hudsonian and Canadian
as applied to the Rocky Mountains, for the Rockies have none
of the characteristic forest trees in common with the Hudson Bay
Region or Canada proper. The only ecologically important tree
common to both regions would be the quaking aspen, which is
not a tree characteristic of either zone, and some botanists regard
the western aspen as distinct from the eastern. When the life
zones are so unlike as they are in the East and in the Rockies,
I think that they should have different names. It would be as
misleading to call our Austro-riparian zone of the Southern
States the Lower Sonoran zone, which is the name of the corre-
sponding zone of the West.

The Rockies are surrounded by plains or tablelands, either
grasslands or desert regions, some belonging to the Submontane
and others to the Upper Sonoran.

Besides these zones long tongues of others intrude into the
Rocky Mountain region, viz. several of the Prairie regions, especi-
ally along the Arkansas, Platte, and Missouri rivers and one from
the Lower Sonoran along the Colorado of the West. The true
Hudsonian and Canadian zones also touch the Rockies at the
headwaters of Athabasca River and northward.

I. Arctic-ALPINE ZONE

This is represented in the Rockies by numerous islands along
the mountain chain and shows very little variation in composition
throughout the whole range. It is true that the Northern Rockies
contain more of the circumpolar arctic plants, and the percentage
of endemic species is somewhat larger in the Southern Rockies,
but the general make-up is practically the same. The arctic-
alpine zone comprises the tops of the higher mountains above the
timber line. The altitude of the latter varies a good deal even
in the same locality, but is found in Colorado between 11,000
and 12,000 feet, in Montana between 7,500 and 9,000 feet altitude,
and in the Canadian Rockies still lower. In the north the timber-
line comes down practically to the sea-level near the arctic coast

480 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

at the mouth of Mackenzie River (Lat. 69°), but it swings south-
ward going east, so that it meets the Hudson Bay about 10°
further south. On the Labrador Peninsula the most northern
point is also about Lat. 59°. The flora consists mostly of low
perennial herbs and a few depressed shrubs. There is no distinct
shrub-belt as in the Alps or the Scandinavian Mountains. I have
already discussed the composition, distribution, and origin of its
flora in three articles published in the Bulletin of the Torrey
Botanical Club.
II. SUBALPINE ZONE

This is practically the same as Dr. Merriam’s Hudsonian Zone
and corresponds to the true Hudsonian Zone of the East, to the
dwarf birch region of the Scandinavian Mountains or the sub-
alpine regions of Switzerland with Pinus montana, Alnus viridis,
and species of Rhododendron. It resembles most that of the
eastern Hudsonian, as the forest consists of spruces, balsams,
larches, and aspens, but of these the only species in common is
Populus tremuloides. The characteristic trees of the eastern
Hudsonian are Picea canadensis and P. Mariana, Abies balsamifera,
and Larix laricina; those of the Subalpine Zone of the Rockies are
Picea Engelmanni, Abies lasiocarpa, and Larix Lyallii, the last
only in the Northern Rockies. These three trees are also found
in the Cascades, i. e., the northern part of the Pacific highlands.
On the more exposed and drier ridges, especially on the southern
side of the mountains, two pines are found, viz. Pinus albicaulis
in the Northern and P. aristata in the Southern Rockies, but
neither is of any great importance.

Merriam! in his life zones of Idaho distinguishes between a
Subalpine or Timberline Zone and a Hudsonian or Spruce Zone;
the former being the region between the upper and lower timber
lines. Such a zone can not be upheld from a botanical viewpoint
and evidently Dr. Merriam has given up the idea. The open
grass-covered areas of this region are essentially Alpine-arctic,
while the wooded spots belong to the Subalpine or so-called
Hudsonian Zone. Mr. Vernon Bailey,2 who follows Merriam
very closely, in his Life Zones and Crop Zones of New Mexico seems
to have limited the Hudsonian Zone nearly to what Merriam at

' North American Fauna 5: 22. 1891.
* North American Fauna 35: 11. 1913.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 481

the place cited called the Subalpine Zone, for he states: ‘‘ Hud-
sonian, the zone of dwarf spruces, occurs as a narrow belt of the
scrubby timber line trees around the high peaks.’ I am inclined
to make the zone broader, including Dr. Merriam’s whole spruce
zone, or of about the same extent as the Hudsonian Zone of
Piper’s Flora of Washington.t I have regarded this zone as
extending from the timber line to the average lower limit of the
subalpine fir (Abzes lasiocarpa) or in Colorado at the upper limit
of the bull pine (Pinus scopulorum), i. e., down to about 10,000
feet in Colorado, 8,000 in the Yellowstone Park, 6,500 feet in
northern Montana, and still lower in the Canadian Rockies and the
Selkirks. It would not do to set it at the lower limit of Engelmann
spruce or the aspen, for both are found far down into the Montane
Zone. As Picea Engelmanni is the most characteristic species
this zone may be called the Spruce Belt.

As to the differences between the floras of the Northern and
Southern Rockies, they are not very conspicuous in the Subalpine
Zone. As stated before, Larix Lyallit is lacking in the Southern
Rockies. So are also Tsuga heterophylla and Pinus albicaults,
whose place on the dry ridges is taken by P. aristata. The
undergrowth is practically the same, consisting of Arctostaphylos
Uva-ursi, Lepargyraea canadensis, Linnaea americana, species of
Sambucus, Pyrola, Aquilegia, Vaccinium, etc. Some of these are
also common to the Hudsonian Zone of the East or tothe Montane
Zone of the Rockies.

III. MoNnTANE ZONE

This corresponds to the Canadian Zone of Merriam, but it is not
like the Canadian Zone of the East. The two important pines
of the Canadian forests, Pinus Strobus and P. resinosa, and the
Arbor Vitae, Thuya occidentalis, do not go further west than Lake
Winnipeg and only Pinus Banksiana (with the spruces mentioned
under the subarctic zone) reaches the foothills of the Rockies.
Of the deciduous trees, only Populus tremuloides, P. balsamzfera,
Betula papyrifera, and a few willows are common to the East and
the Rockies. It is true that some of the undergrowth consists of
plants common to both regions, but most of the species of such
genera as Vaccinium, Lonicera, Symphoricarpos, etc. are different.

1 Contr. U. S. Nat. Herb. 11: 1906.
32

482 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Nothing in the East corresponds to the characteristic and con-
spicuous Odostemon (Berberis) Aquifolium and Pachystima Myr-
stnites of the Rockies, and Echinopanax horrida is found only as
a waif at the western end of Lake Superior. The conspicuous genera
Castilleja, Pentstemon, Aquilegia, Arnica, represented by numerous
species in the Rockies, are poorly represented in the Canadian
flora. Dr. Merriam has made the statement,! ‘In a communica-
tion already referred to, I stated the conclusion that the commonly
accepted division of the United States into Eastern, Middle, and
Western Provinces had no existence in nature and that the whole ex-
tra-tropical North America consists of but two primary life regions,
a boreal region which is circumpolar, and a Sonoran or Mexican
Tableland region which is unique.’’ These statements are far from
correct when the plants are considered. It may be that the animals,
which are less dependent on soil, moisture, and other conditions, and
are endowed with locomotion, might be the same in the western part
of the northern woods (Hudsonian and Canadian Zone) and the
forested region of the Rockies, but as far as the flora is concerned
it is not the same. Though the two regions touch at the head-
waters of the Athabasca River and north, there is not a single of
the characteristic forest trees in common. The only tree of
general distribution common to the two regions is, as mentioned
before, the aspen, and some botanists, Tidestrom, Wooton and
Standley, etc., regard the western a distinct species, Populus
aurea; and others, Daniels, etc., as ‘a distinct variety. The
boundary line between the eastern woods and those of the Rockies
is more distinct than between the different life zones of the Rockies.
Many species, as for instance the sage brush and several species
of poplars and willows, are found both in the Montane (Canadian
of Merriam) Zone and the Upper Sonoran, not to speak of all
that are common to Merriam’s Canadian and Transition or his
Transition and Upper Sonoran.

If we compare the Montane Zone of the Rockies and that of
the Pacific Coast mountains, we find that they have many more
speciesincommon.* Thisis due partly to the fact that the Cascades
and the Northern Rockies are connected by many mountain
ranges. Many of the Rocky Mountain plants have migrated
into the Cascades, and several of those belonging to the Pacific

'See Proc. Biol. Soc. Wash. 7: 58. 1892.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 483

Mountains are found on the western slope of the Northern Rockies.
Some have also migrated across the Great Basin from the Sierra
Nevada to the Southern Rockies, or vice versa from mountain to
mountain. Of the forest trees may be mentioned the following
categories: (1) Species of general distribution in both regions:
Pinus Murrayana, P. flexilis, P. albicaulis, Pseudotsuga mucronata,
Alnus tenutfolia, Populus tremuloides, and Pinus ponderosa, if
Pinus scopulorum is included in it as a variety. (2) Species com-
mon to the Sierra Nevada and the Southern Rockies: Abies con-
color and Pinus aristata. (3) Western species, whose ranges
extend to the western slopes of the Rockies: Larix occidentalis,
Abies grandis, Tsuga heterophylla, Thuya plicata, Pinus monticola,
Taxus brevifolia, Populus trichocarpa, Betula occidentalis, etc.
These may all be regarded as immigrants. (4) Rocky Mountain
species which have migrated into the Cascade Mountains but
which are not found in the Sierra Nevada, as Picea Engelmanni
and Abies lastocarpa. (5) The endemic species confined to the
Rockies only are: Picea Parryana, P. albertiana, Populus angusti-
folia, Betula fontinalis, etc. From this it may be inferred that
the difference between the Montane Zone in the Rockies and the
Pacific Mountains is much less than between the former and the
Canadian Forest. The mountains of the Pacific slope and the
Rockies might be included in the same province, were it not for the
lack in the latter of many of the most characteristic trees of the
former, as for instance, the sugar and other Californian pines,
the redwoods and “big trees,’’ the cypresses, etc.

Many differences are found between the Montane Zone of the
Northern and of the Southern Rockies. Here it may suffice to
give a summary of the differences in the composition of the forest
trees from an article already published. (1) Trees common to
the both divisions are Pinus Murrayana, P. scopulorum, P. flexilis,
Pseudotsuga mucronata, Picea Engelmanni, Sabina scopulorum,
Populus tremuloides, P. balsamtifera, and P. angustifolia, Betula
fontinalis, Alnus tenuifolia, and several willows. (2) Trees found
in the Southern but not in the Northern Rockies are: Picea Parry-
ana, Abies concolor, and Betula utahensis. (3) Those found in
the Northern Rockies but not in the Southern: Picea albertiana,
Pinus albicaulis, several species of Betula, Populus, and Salix,
and the conifers mentioned above as immigrants from the Cascade
Mountains.

484 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

As the flora of the Montane Zone is mostly made up of different
pines and Pseudotsuga mucronata it may be called the Belt of
Pines and Red Fir.

The upper limit of this zone I have placed at the upper limit of
the Bull Pine in Colorado, for here the Douglas Spruce and Lodge
Pole Pine extend far up into what I regard as the Subalpine Zone.
In the Northern Rockies it may be placed at the upper limit of
the Red or Douglas Fir and that of most of the immigrants from
the Cascades. This means an altitude of about 10,000 feet in
Colorado, 8,000 in the Yellowstone Park and 6,500 feet in northern
Montana. The zone so limited would extend north to Lat. 55°,
though the Lodge-Pole Pine extends about 10° further north.
Of the trees belonging to the Canadian Zone of the East, the
Banksian Pine extends in a similar way further north than the
other members. The lower limit has been placed at the lower
limit of the Lodge-Pole Pine. This is also near the lower limit
of the Limber Pine and that of the Douglas Spruce, east of the
mountains. The lower limit of the Montane Zone is therefore
about an altitude of 7,500 or 8,000 in Colorado and 5,000 feet in
southern Montana. It is rather lower on the western side, about
4,000 feet in western Idaho. For some reasons to be mentioned
later it might have been better to have set the lower limit further
down, perhaps at the lower limit of the Douglas Spruce, which
would carry it 1,500 feet further down.

IV. SUBMONTANE ZONE

This corresponds mainly to Dr. Merriam’s Transition Zone.
It has scarcely anything in common with the Transition Zone of the
East, the Alleghanian hardwoods, with oaks, chestnuts, walnuts
and hickories; but even Dr. Merriam did not regard it as a life
zone proper, but a transition belt between the boreal and austral
zones. Seen from such a view it is a transition zone between the
wooded mountains and the grass-covered plains or between the
Rocky Mountains proper and the Sonoran highland.

Merriam included also in his Arid Transition Zone the plains
of the western Dakotas, northern Montana, part of Saskatchewan
and Alberta. He was correct so far, but did not extend it far
enough south. I shall discuss this further on under the headings
of the Great Plains.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 485

The foothills are far from uniform, depending partly on the
region on which they border; those of the eastern slope are very
different from those of the western, those in the south different
from those in the north. In the foothills are included both the
lower mountains of the Rockies, the high mesas and plateaus often
bordering on the same, and the isolated mountains, hills, and
bluffs in the neighboring region.

1. Foothills of the eastern slope of the Northern Rockies

The foothills are here usually covered with scattered growth of
Bull Pine, Pinus scopulorum, and on the steeper hillsides by
Sabina scopulorum, and to a great extent covered with the common
grasses and other herbs of the plains. In the upper portion of
the hills, Pseudotsuga mucronata and other trees of the Montane
Zone are often found in the valleys. The river bluff and hill-
sides with richer soil are covered by groves of Prunus melanocar pa,
Grossularia setosa, Ribes odoratum, R. inebrians, Acer Douglasu,
Rhus trilobata, Symphoricarpos occidentalis, Amelanchier alnifolia,
and related species. In the canyons and valleys are groves of
Populus angustifolia, P. Sargentii, P. acuminata, some willows and
birches, Negundo interior, and in the drier part of the same Prunus
americana and several species of Crataegus. Many of these trees
and shrubs really belong to the flora of the Plains or even to
prairie-division of the Upper Austral Zone, and have followed the
rivers up. In the Black Hills of South Dakota and in some of
the hills and ridges in western Nebraska to these are added,
Quercus macrocarpa, Ostrya virginica, Celtis occidentalis and C.
crassifolia, Ulmus americana, Fraxinus campestris, and Cercocarpus
montanus, all except the last belonging to the eastern flora. The
lower hills, as well as tablelands and flats, are often covered by
sage brush, principally Artemisia tridentata and A. cana, and
rabbit brush, i. e., various species of Chrysothamnus.

Although the foothill region in central Montana covers large
areas, the zone is really rather narrow in altitude and becomes
still narrower further north. As far as I can understand, it has
disappeared in the Canadian Rockies. At least, the hills sparingly
covered by Pinus scopulorum so characteristic of the belt in
Montana, northern Wyoming, and western Nebraska are not
there. Even the tree itself seems to be lacking north of latitude

486 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

49° east of the mountains. The most northern record is in the
Bear Paw and Little Rocky Mountains in Northern Montana, a
little north of Lat. 48°.

2. Foothills of the northeastern slope of the southern Rockies

In Wyoming and northern Colorado the eastern foothills of the
Southern Rockies are much the same as those of the Northern
Rockies already described, but Pseudotsuga mucronata is perhaps a
little more common and the sage brush is rare. In some cases
the mesas and hills are covered by shrubs, as Cercocarpus mon-
tanus, Rhus trilobata, Ribes inebrians, june-berries and _ roses,
occasionally also Celtis rugosa. This description may apply to
the foothills north of South Platte River. In this region the
pinons and shrub oaks are rare, but south of said river the foot-
hills take on a different aspect. In other words, the division line
between the northern and southern foothills is on the eastern
slope of the Rockies over two degrees further south than the line
between the northern and southern division in the Montane Zone.

3. Foothills of the southern and western slopes of the southern Rockies

This division takes in the eastern slope south of the South
Platte River (about Lat. 39° 30’), the whole southern slope and
the western slope, at least as far north as the Grand River, prob-
ably as far north as Yampa River (Lat. 40° 30’), and very likely
the southern slope of the Uintahs and the eastern of the Wasatches.
In these are included the isolated La Sal and Abajo Mountains of
southeastern Utah, but the Henry Mountains and other mountains
west of the Colorado of the West belong to the Great Basin. The
flora in the zone is by no means uniform. Often it consists of
several belts one above the other, sometimes the species of the
different belts are intermixed. If the zonation is present, the
belts are often in the following order: (1) Pine Belt, highest; (2)
Chaparral Belt; (3) Pinon-Cedar Belt.

a. Pine Belt
The Pine Belt is mostly made up of an open stand of Pinus
scopulorum, mixed with some Sabina scopulorum and Pseudotsuga
mucronata, and arborescent oaks, with Padus melanocarpa and P.
valida, Acer glabrum, Robinia neomexicana, and species of Crataegus
in the moister places.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 487

b. Chaparral Belt

The Chaparral is mostly made up of shrub oaks, principally of
the Quercus Gambelit group, with deciduous leaves. The ever-
green oaks mostly belong to the Upper Sonoran flora. The oaks
often grow in pure stand in dense thickets, but often are mixed
with species of Amelanchier, Rosa, Symphoricarpos, Cercocarpus,
Ribes, and other shrubs.

The valley and canyon flora of both these belts consist of
Populus Sargentu, P. Wislizent, P. acuminata, P. angustifolia,
Betula fontinalis, Alnus tenutfolia, and willows.

c. Pinon-Cedar Belt

This belt is characterized by an open stand of Pinus edulis and
_ Sabina monosperma and on the western side also of S. utahensis.
It may be counted to the foothills, but Merriam,! Vernon Bailey,?
and Wooton & Standley,*® refer this to Upper Sonoran Zone.
Although the undergrowth in it is much the same as that of the
Pine Belt, and though the vegetation is quite different from that
of the Great Basin proper, which also belongs to the Upper So-
noran, and plant societies from the three belts often mix, it is
better to leave it in the Upper Sonoran Zone as they have done.
It will be discussed fuller later.

4. Western foothills of the Wasatches

This slope is much like that of the western slope of the Southern
Rockies, though the Pine Belt is poorly developed, perhaps
destroyed by man, and in the other belts there are found many
immigrants from the Great Basin Mountains. The Chapparal
extends north to about Lat. 43°. If the Pinon-Cedar Belt is in-
cluded in the foothills an important element is added, viz. Pinus
mono phylla.

5. Foothills of the Green River Basin

Here the Chaparral Belt has wholly disappeared and of the
Pinon-Cedar Belt, Sabina utahensis is the only one of the charac-
teristic trees left.

1N. Am. Fauna 3: 20. 1890.

2.N. Am. Fauna 35: 35. 1913.
S Contr Wei: eNate ethos th, 37.0 LOLS.

488 | MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

6. Southwestern foothills of Northern Rockies

In central Idaho the foothill flora is very meager as far as
woody plants are concerned. Bull Pine is practically wanting,
and both the oaks and junipers have disappeared. The woody
vegetation of the drier hillsides is mostly made up of shrubs,
such as species of Artemisia, Chrysothamnus, Tetradymia, Eurotia,
etc. The mountain mahoganies, Cercocarpus ledifolius and C.
hypoleucus, are also found there. Along the water courses are ©
found species of Populus, Salix, Crataegus, Amelanchier, Betula,
and Alnus.

7. Western foothills of the Northern Rockies

In British Columbia there are no foothill regions of the Rockies,
for, as said before, they connect here through several mountain
ridges with the Cascades. I have not visited personally the west
side of the Bitter Root Mountains, but have received the impres-
sion from what I have read that there is a broad belt of Yellow
Pine, Pinus ponderosa, on the higher plains bordering these
mountains. These woods Piper includes in the arid portion of
the Transition Zone. Judging from the little I have seen of the
Flathead Basin between the Rockies proper and the Bitter Roots,
one may scarcely speak of any distinct foothills, as no other transi-
tion flora exists there than what we find in any mountain valley
between the hillsides and the bottomlands.

As seen from above, the Pine Belt only, consisting of scattered
Pinus scopulorum and Sabina scopulorum, is present on the eastern
slope of the Northern Rockies and the northeastern slope of the
Southern. In the southern part of the western slope of the
Northern Rockies where the Bull Pine is absent the belt is also
absent as a Pine Belt and in the northern part its place is taken by
P. ponderosa. As Pinus scopulorum is the one of the mountain trees
that grows at lowest altitudes, it naturally is the tree that runs
further down on the hills or further out on the plains, and is the
one that really is concerned in the strife between the mountain
forest and the grasslands of the plain, or between the Montane
evergreens and the Submontane deciduous trees. It is one of the
important components of the Montane flora and should be counted
there, but as it encroaches so much on the Submontane floral
districts, and its close relative, Pinus ponderosa, is the charac-

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 489

teristic tree of the Submontane forest of eastern Washington, it is
better to treat the region of scattered Bull Pines as a zone by
itself, although in reality it is only a transition belt between two
life zones.

The belt of chaparral is really the true representative of the
hardwood forest of the Alleghanian Zone of the East and the
Submontane zone of oaks, chestnuts, and walnuts of Europe. It is
true that it is a poor representative thereof, not only as to the
size of the trees (or rather shrubs), but also as to the extent of
the zone itself. Marcus E. Jones, who has studied the flora of
Utah, California, and Arizona, has come to the same conclusion,
though other ideas of his regarding limitations of zones and prov-
inces are somewhat faulty. A little north of the Arkansas Divide
(about Lat. 39°), this belt disappears on the east side of the Rockies.
It reaches there its northern limit at the altitude at which the
grass-covered plains reach the mountains. ‘The life zone is evi-
dently here continued on the plains as grasslands, and naturally the
oaks disappear. The hardwood belt reappears partly in the foot-
hills of the Black Hills, but here it contains only eastern species,
such as Quercus macrocarpa, Ulmus americana, Ostrya virginica,
GCC;

8. The Great Plains

The Rockies are bordered on the east by the Plains. These
slope,in Colorado and Kansas, about 3,500 feet in 5 degrees of
longitude or 10 feet to the mile, 1. e., decreasing in altitude from
about 6,000 feet to 2,500 feet. In the north the slope is still
more gentle, in northern Montana and North Dakota about 2,000
feet in 13 degrees or 10 feet in 41% miles from about 4,000 to 2,000
feet altitude. From this can also be seen that the plains are higher
in the south and lower in the north, i. e., that the slope is south-
west to northeast. The northern part of the plains Dr. Merriam
included in the arid division of the Transition Zone, the southern
part in the Upper Sonoran. In this I agree, but I do ‘not
agree as to the limitation of these zones. ‘The maps which Dr.
Merriam has issued at different times vary a good deal, but in all I
have seen the Upper Sonoran Zone is carried to the north into west-
ern South Dakota and southeastern Montana and in the one pub-
lished in 1898, with his ‘‘Life zones and crop zones of the United
States,’’! it includes even one third of Montana, Wyoming, and

1U.S. Dept. Agr. Div. Biol. Surv. Bull. 10: 1898.

490 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Nebraska and part of South Dakota. In my opinion, these parts
do not belong to the Upper Sonoran Zone. In the Bulletin men-
tioned, I can not find any statement giving the reason why this
region is included in the Upper Sonoran Zone, and why the north-
ern part, viz. northeastern Montana, eastern Alberta, Saskatche-
wan, and western North Dakota, is excluded. Perhaps the zone
is based wholly on animal distribution, for the flora does not
warrant such a division. Maybe the occurrence of austral types
in this region has lead to the error. But then the question arises,
were these austral types Sonoran or were they from the eastern
Upper Austral Zone. The true prairie region belongs to that
zone and it extends along the Missouri Valley through South
Dakota into Montana and along the North Platte and Cheyenne
River valleys into Wyoming.

The flora of the Great Plains from the Arkansas Divide in Col-
orado to the divide between the Saskatchewan and Athabasca
rivers in the north, and from about the 100° meridian to the foot-
hills of the Rockies, is practically the same. The characteristic
grasses, Koeleria nitida (vernal facies), and the two gramas,
Bouteloua oligostachya, B. hirsuta (autumnal facies) on the plains
proper, Andropogon scoparius and Bouteloua curtipendula on the
hills, and Agropyron Smithit, A. molle, etc., in alkaline soil, are
found from southern Colorado to Saskatchewan, and the Buffalo
grass, Bulbilis dactyloides, is scattered over the region, except in
the northern portion. The common trees and shrubs of the hill-
sides, Padus melanocarpa, Rhus trilobata, Toxicodendron Rydbergii,
Grossularia odorata, and Symphoricarpos occidentalis, extend north
to northern Montana or Alberta. It is true that some of these,
as for instance Bouteloua oligostachya, B. curtipendula, and B.
hirsuta are also found in the Sonoran Region, but they are the only
ones among their numerous relatives which are found on the
plains north of the Arkansas Divide. Of the cactuses, Opuntia
polyacantha and Cactus viviparus range from Colorado to Sas-
katchewan and Opuntia fragilis and Cactus missouriensis to
northern Montana.

South of the Arkansas Divide are found many plants either not
found north thereof or not extending far north thereof. Among
the grasses may be mentioned Amphilophis Torreyanus, Bouteloua
polystachya, B. eriopoda, B. prostrata, Scleropogon brevifolius, and

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 49I

Erioneuron pilosum, which are found in Colorado only south of
the divide. The cactuses also are here represented by genera
not found north of the divide, as Echinocactus, Echinocereus, and
the section Cylindropuntia of Opuntia. The tree cactus, Opuntia
arborescens, is found on the Arkansas Divide, but not north
thereof. Even the other sections of Opuntia and the genus
Cactus are mostly represented by different species. The yuccas
so common in the Upper Sonoran Zone are represented north of the
divide by only one species, Yucca glauca, which ranges north to
South Dakota. The genera Dasylirion and Nolina are found
only on the south side. Several species of Padus and Rhus are
added south of the divide. Genera characteristic of the plains,
such as Lesguerella, Eriogonum, etc. are mostly represented by
different species south of the line. Atriplex confertifolia, the
Shad-Scale of the Great Basin, is not uncommon south of the
divide, but is not found north thereof.

It is therefore evident that the line between the northern
plains and the southern should not be drawn in Montana but in-
Colorado. Looking at Dr. Merriam’s map of 1898, one may
wonder how it happens that the Upper Austral Zone should
swing northward towards the Rockies where the plain becomes
higher and that northern Iowa and northern Illinois should be
counted to the Transition Zone, while eastern Montana 4° or 5°
further north and 2,000-3,000 feet higher, or central Wyoming
on the same latitude and over 4,000 feet higher, should be counted
to the Upper Sonoran, the zone next below it.

If we let the plains as far south as central Colorado belong to
the Transition Zone, i. e., if we let a region 3° or 4° degrees
further south and 4,000 or 4,500 feet higher than northern Iowa
and northern Illinois be on the southern boundary line of the
same life zone, it seems much more reasonable. When my obser-
vations relative to the native flora and the generally accepted
relation between latitude and altitude point to the same conclu-
sion, I can not see any reason why we should not draw the line
between the so-called Transition Zone and the Upper Sonoran
on the plains where I have drawn it.

I know very little about the distribution of animals, but I think
that several illustrations may be found supporting my theory.
I know at least of one, viz. the distribution of the two species of

492 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

jack-rabbits, of which the northern species, the common jack-rabbit
or prairie hare, ranges from Saskatchewan to southern Colorado,
i. e., a little south of the Arkansas Divide, and the southern
species, the black-tailed jack-rabbit, from Mexico and Texas on
the eastern side to northern Colorado, a little north of the divide.

The plains east of the Rockies may therefore be divided into
two life zones as far as the native flora is concerned.

I. The GREAT PLAINS, north of the Arkansas Divide, and
belonging to the Subboreal or Transition Zone.

2. The STAKED PLAINS, south of the divide and belonging to the
Upper Sonoran division of the Austral Zone.

9g. Columbia Plains

The upper part of the Columbia Plains belongs also to the
Submontane Zone. For a description I shall only refer to Piper’s
Flora of Washington.?

V. UppER SONORAN ZONE

Just as the Submontane Zone runs across the mountains and
forms the bottom of the saddle between the Northern and South-
ern Rockies, so does the Upper Sonoran Zone in the saddle between
the Southern Rockies and Sierra Madre of northern Mexico.
Just as the Submontane Zone is made up of two principal divisions,
(1) The wooded hilly or broken country, and (2) The grass-covered
plains, so is also the Upper Sonoran region bordering the Southern
Rockies, but the plains are not always covered by grasslands.
This is especially the case on the western side of the mountains.
The Upper Sonoran division of the Rocky Mountain region may
be divided into the following divisions:

Pinon-Cedar Belt.
Staked Plains.
Great Basin, including the basins of the Colorado and
Snake Rivers.
4. Columbia Plains.

Ww NO

1. Pinon-Cedar Belt
This has already been mentioned under the Foothills. It is
made up of hills or tablelands mostly covered by an open stand of

1 Contr. U. S. Nat. Herb. 11: 1906.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 493

Pinus edulis and Sabina monosperma, and, on the western side,
Sabina occidentalis also. It extends on the eastern side over the
Arkansas Divide to South Platte River (Lat. 39°). North of
that river both the pinon and the cedar are only local and soon
disappear altogether. On the western side it forms foothills of
the Rockies and a few isolated mountains, as well as low plateaus
apparently as far north as the Yampa River. On the western
slope of the Wasatch Mountains and in the mountains south
thereof as far east as the Henry Mountains, Pinus edulis is mixed
with P. monophylla, which takes its place in the isolated moun-
tains of the Great Basin as far north as southern Idaho. In the
part bordering the deserts the Pinon-Cedar Belt is often broken
and intermixed with patches of sage brush, Artemisia tridentata,
as for example, on the mesas between the Elk Mountains and
San Juan River in southeastern Utah.

On the western slopes of the La Sal Mountains the Pinon-Cedar
Belt reaches the top of Wilson’s Mesa, nearly 8,000 feet in alti-
tude, and is separated by a narrow belt of chaparral only a few
hundred feet high, from the Spruce Zone above, both the foothill
Pine Belt and the Montane Forest Zone being lacking. The Pinon-
Cedar Belt, furthermore, was there separated from the valley
below with the Upper Sonoran flora by a belt of low shrubs of
Amelanchter utahensis, Cercocarpus, Coelogyne, Petradoria, Yucca,
Fendlera, Ephedra, Cowania, Fallugia, and Quercus, some of
which belong to the Upper Sonoran flora, and some to that of
the chaparrals.

The undergrowth of the Pinon-Cedar Belt is often the same as
in the Transition Pine Belt, but often many southern plants are
added, as for instance Arctostaphylos platyphylla, Ceanothus
Greggit, Berberis Fremonti, etc. In southeastern Utah large
stretches are covered by Amelanchier utahensis and other shrubs.
Towards the San Juan River the mesas are sparingly covered by
Coelogyne, which, if I am not mistaken, associates further south
with Covillea, one of the characteristic plants of the Lower Sonoran
Zone. In southern Utah, Arizona, and New Mexico, the place
of the pinons and cedars is often taken by live oaks, especially
on the sides of canons. In the canons, Fraxinus anomala is
common. In southern Arizona and New Mexico many other
trees and shrubs are added to the belt, but as that region belongs

494 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

to Sierra Madre rather than to the Rockies, it will not be discussed
here.

The eastern representative of the Upper Sonoran Zone is the
wooded division of the Upper Austral Zone or the Carolinian Zone.
This is also characterized partly by evergreen forests of conifers,
as the short-leaved pine, partly of deciduous broad-leaved trees,
as rose-magnolia, tulip-tree, persimmon, hickory, oak, and walnut.
The live-oaks seem lacking. This zone corresponds to the Medi-
terranean region with evergreens of both classes, as pinons,
cypresses, and junipers, as well as live-oaks, olives, laurels, etc.
The true prairies are probably the grass-covered portion of this
zone in the Middle West.

2. Staked Plains
These are discussed already under the Great Plains.

3. Great Basin

The Great Basin comprises the larger part of Utah and Nevada,
northern Arizona, southern Idaho, and small parts of New Mexico,
Colorado, Wyoming, Oregon, and California. In it is included
the Great Basin proper, without outlet, and the upper basins of
the Colorado of the West and Snake River. The flora of the
basin is a desert flora, characterized by such shrubs as Atriplex
confertifolia and other species of that genus, Artemisia tridentata
and its relatives, Sarcobatus, Graya, Tetradymia, Yucca, and num-
erous species of Eriogonum (both shrubby and herbaceous).

4. Columbia Plains

These I have not visited personally and shall only refer to the
description in Piper’s Flora of Washington.

VI. Lower SONORAN ZONE

The Lower Sonoran Zone consists mostly of desert lands. The
woody vegetation is characterized by the Creosote Bush (Covillea),
mesquites (Prosopis), acacias, cactuses, yuccas, and agaves. In
the Middle Province, it may be divided into two divisions, the
Texano-Mexican Region east of the mountains, and the true
Sonoran Region west thereof. The former send up two tongues
northward along the valleys of the Rio Grande and the Pecos,

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 495

but neither reaches the Rockies proper. The latter sends up
three such tongues, one along the Colorado of the West, another
along the Virgin River, and the third along the eastern slope of
the Sierra Nevada. Only the first of these may be considered
in connection with the Rocky Mountains, as a few plants be-
longing to this zone reach the foot of the mountains along the
Grand and the San Juan, two rivers of the Colorado River system.
On the Pacific Coast there are two other regions belonging to the
Lower Sonoran Zone, viz. the Sacramento-San Joaquin Valley
and the Lower Californian region. In the East this is represented
by the humid Austro-Riparian Zone. It is the region of the
Long-leaf and Loblolly pines, magnolias, cypress, tupelo, and
live-oaks. It corresponds to the regions of oranges and date
palms in the Mediterranian Region.

SUMMARY

The results of my investigations show, as far as the native flora
is concerned:

1. That the United States may be divided into three floral
provinces, an eastern or Alleghanian, a middle or Rocky Mountain,
and a western or Pacific. As far as the native flora is concerned,
Dr. Merriam is wrong in his contentions that no such a division
exists in nature.

2. That going north and south or down the mountains one may
recognize six life zones in the Rocky Mountains. My observa-
tions in that respect agree with those of Dr. Merriam, but I have
used different names, names that have been used by phyto-
geographers in Europe. They are:

1. Alpine-Arctic.
. Subalpine-Subarctic, or Hudsonian of Merriam.
. Montane-Boreal, or Canadian of Merriam.
. Submontane-Subboreal, or Transition of Merriam.
. Upper Austral or Upper Sonoran.

. Lower Austral or Lower Sonoran.

ae That the Arctic-Alpine Zone is practically the same in all
three divisions, as it is essentially all over the world.

4. That the composition of the flora of the corresponding life
zones of the eastern and middle divisions otherwise show greater
differences than even the parallel zones of the same division, and

Auf wn

496 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

scarcely less than the corresponding zones of Europe and North
America.

5. That the Subarctic and Boreal zones of the eastern and
middle divisions, although they meet in the north without a barriers,
have practically none of the characteristic plant species in common;
the common plants consisting mostly of transcontinental plants,
many of which are also found in the Old World or in other life
zones.

6. That the same zones of the middle and western divisions
because of the connections in the north between the Cascades and
the Rockies have many of the characteristic species in common,
especially in the north, and that there is less reason for keeping
these two divisions distinct. They could be regarded as one
division, if it were not for the absence of spruce and balsam in
the southern part of the western division, and the total absence
of redwoods, cypresses, sugar pines, and several other western
pines in the middle division.

7. That the Submontane, Upper and Lower Sonoran zones of
the Rockies have practically no elements in common with the corre-
sponding zones of the Atlantic Coast, being separated from that
region by the grass-covered plains.

8. That the Submontane zones of the middle and western divi-
sion, i. e., of the Rockies and the Sierra Nevada, have rather few
plants in common, as they are separated more or less by the
Great Basin.

g. That the Upper and Lower Sonoran zones of these two divi-
sions merge, more or less, as there is no real effective barrier.

10. That the Arctic-Alpine region naturally has no wooded
division, that the Subarctic or Subalpine and the Boreal or Mon-
tane zones in America have no grasslands of any extent and that
the Subboreal, Upper and Lower Austral zones have both wooded
regions and grasslands or deserts.

11. That the Subarctic-Subalpine zones of both the eastern and
middle divisions are characterized by a spruce-balsam forest,
though the species are different. That this forest is lacking in
the western division, except in the Cascades, where the species of
the middle division have invaded the zone. In Europe the zone
is represented by the dwarf birch belt in the Scandinavian moun-
tains, and the region of Pinus monticola, Alnus viridis, and erica-
ceous shrubs in the Alps.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 497

12. That the Boreal or Montane Zone is characterized by a pine
forest in all three divisions in North America, as well as in Eu-
rope, where, however, there are also steppe-lands, especially in
Russia.

13. That the woods of the Subboreal Zone (Transition Zone of
Merriam) in all three divisions as well as in Europe are charac-
terized by deciduous trees, mainly oaks and other nut-bearing
trees, and that this zone is but poorly developed in the Rockies,
consisting mostly of chaparrals of scrub oaks, Amelanchier,
Cercocarpus, etc. .

14. That the woods of the Upper Austral zones (in the West
called Upper Sonoran) in all three divisions in America are mostly
made up of evergreens, partly of broad-leaved trees and shrubs,
principally live oaks, partly of conifers, as, for instance, pines,
junipers, and cypresses. The same is the case in Europe.

15. [hat the Lower Sonoran Zone, characterized further south
in the middle and the western divisions by the mesquite, creosote
bush, giant cactuses, and tree yuccas, is poorly represented in the
Rockies, and there only in the canons and valleys of the Colorado
of the West and its tributaries. It corresponds to the Austro-
Riparian district of the East with pines, magnolias, cypresses,
and live oaks, and to the region of oranges and date palms of
the Mediterranean.

16. That going north or up the mountains we find no sharp lines
between the parallel zones, or going east and west between grass-
lands or desert and forest, but everywhere we find transition belts
or zones of strife between neighboring floras.

17. That the original Subalpine or Timber Line Zone of Dr.
Merriam, which he has abolished, is merely such a transition belt
or zone of strife between the Alpine Zone and what I have called
the Subalpine Zone, or Dr. Merriam’s Hudsonian Zone.

18. That the Subalpine Zone, or so-called Hudsonian, gradually
emerges into the Montane or Canadian Zone. As both contain
coniferous woods, the transition is gradual and no distinct transi-
tion belt is evident.

19. That Dr. Merriam’s original Transition Zone as designated
in his survey of the San Francisco Mountains does not in my
opinion correspond to his Transition Zone of the East, viz., the
Alleghanian Zone of hardwood forest. The open woods of Pinus

498 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

scopulorum represent the zone of strife either between the mon-
tane pine forests and the grassy plains, as for instance in western
Nebraska and northern Colorado, or between the former and the
chaparral belt in southern Colorado. Sometimes the latter
disappears and the strife is between the Montane and the Upper
Sonoran.

20. That the Chaparral Belt is the true representative in the
Rockies of the Alleghanian Zone or submontane hardwoods of
Europe.

21. That the Great Plains north of the Arkansas Divide repre-
sent the grasslands of this zone and not of the Upper Austral or
Upper Sonoran, as partly claimed by Dr. Merriam. They begin
at about the same latitude as that at which the chaparral dis-
appears. That the higher part of the Columbia Plains also belongs
to this life zone.

22. That the Staked Plains south of the Arkansas Divide should
be counted in the Upper Sonoran Zone as well as the Great Basin
and a part of the Columbia Plains. In this I agree with Dr.
Merriam.

23. That Dr. Merriam is right in counting the Lower Sonoran
to the warm temperate zones and Marcus E. Jones wrong in
placing it among the tropical.

24. That the prairie region of the Upper Austral Zone of the
East sends long arms along the valleys of Missouri, Platte, Ar-
kansas, and other rivers into the Great Plains, which arms carry
some of the prairie plants to the foot of the Rockies.

25. [That the Lower Sonoran sends up similar arms along the
Colorado of the West and its tributaries and the Rio Grande.

26. That the mountain regions of the middle division may be
divided into three parts which show some differences in the
composition of the flora, viz., the Northern Rockies, the Southern
Rockies, and the Sierra Madre. The division lines in the Montane
Zone between these are the saddles in central Wyoming and New
Mexico, not near the Canadian and Mexican boundaries as Harsh-
berger has indicated. In the Submontane Zone the division line
on the eastern slope is further south about the headwaters of the
South Platte River, and the Upper Sonoran on that side stops on
the Arkansas Divide. On the west side the latter extends north
to the Columbia Plains.

RYDBERG: VEGETATIVE LIFE ZONES OF ROCKY MOUNTAINS 499

27. The approximate altitudinal limits of the different zones in
the south are given below. So also the northern latitudes at
which they meet the lowlands, the plains, or the level basins.

Altitude in New Mexico, Northern latitude
Zones approximately East Side West Side
Alinine-ancticn 1rd eee 12,000—14,400 ft. Lat. 69°-90° Lat. 69°-90°
SMDAN DIME: 3. v2 \y0 delaeee eee cee 10,500-12,000 ‘‘ 55°-69° 55°—69°
Montane: 5. of2n4 aio. feos. OOG-10-500. 48°-55° 50°-55°
. “ec ° IY ° ° °
Sabapuene Citak Pees ene oe eae Soo aoe
Wpper Sonorag: tts as- eo se § 4,500— 7,000 “ 35°—-38° 30’ 35°-42°

Hower SOnOLATIEe eee ee: — 4,500 (in valleys—35°) (in cafions—39°)

a) oie. . ms

| i i a > Se tae

“ve

a at 8

tL.

earner aang al

Liy if ete Me LA:

CD. id

re Se: : ne

BERMUDA FUNGI

FRED J. SEAVER
The New York Botanical Garden

It is often stated by those who have visited the islands that
there are no fungi in Bermuda, at least none to speak of. It is
difficult to account for the prevalence of this idea unless it be that
many of the larger forms which one is accustomed to see in other
places are conspicuous by their absence in Bermuda, or if they do
occur, being short-lived, they are overlooked by visiting botanists.
Many of the fungi are at best so evanescent in their occurrence
that it is difficult to form an adequate conception of the fungous
flora of any region unless the place is visited frequently at different
seasons of the year or for an extended period of time. Even then
the region must be gone over with a ‘‘fine comb”’ in order to get a
fair representation of the smaller and more inconspicuous species.

Whatever explanation may be offered, on account of the reputa-
tion which these islands have had, so far as their fungous flora is
concerned, they seem to have offered no inducement to mycologists.
Or perhaps this phase of their natural history has been over-
shadowed by the opportunities which are afforded for the study of
other cryptogams such as marine algae; at any rate the fungi
have received very little attention. Twenty-four species were
recorded in the report of the Challenger Expedition in 1883.
Professor Farlow has collected and described a few species. In
addition to these published records about forty species were col-
lected by Dr. and Mrs. B. O. Dodge during a recent visit, many of
which were duplicated during our own visit to Bermuda at a
later date.

The parasitic fungi, which on account of their economic im-
portance are the first to attract attention, are quite abundant and
their number is gradually increasing, largely by importation, as
the work of agriculture and horticulture is becoming more extended
in this region. From the observations based on a two weeks’ col-
lecting trip (November 29—-December 14, 1912), the writer is

501

502 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

inclined to believe that the fungous flora of Bermuda, so far as
the number of species is concerned, compares very favorably
with that of any other region of equal extent, notwithstanding the
fact that many of the familiar forms seem to be lacking. Of the
one hundred and fifty species collected during our two weeks’
visit to the islands, many are still undetermined and as this col-
lection must necessarily represent a very small percentage of the
species which actually occur, any report which may be presented
at the present time must at best be regarded as only preliminary
to the study of the fungi of these interesting islands.

Only three species of the Phycomycetes were found. Among
the Peronosporales, or white rusts, Albugo candida (Pers.) Roussel,
was the only species collected. This species, as might be expected,
was found to be common on leaves and stems of cultivated radish.
The Mucorales were found to be represented by Pilobolus crystal-
linus (Wigg.) Tode and an unnamed Mucor.

Four species of the Helvellales were collected. Of these one
species, Geoglossum nigritum Cooke, was found to be abundant on
rocky hillsides among mosses. Tvrichoglossum hirsutum Wrightit
Durand was also found. This variety of ‘‘hairy earth-tongue”’
was described by Durand in his recent monograph of the Geo-
glossaceae. The variety was based on two collections made in
Cuba by Wright. At the time of the original description of the
variety it was predicted by the author of the variety that it would
probably prove to be a distinct species. The material collected
in Bermuda according to a communication from Durand has
served to confirm this suspicion. Tvrichoglossum hirsutum (Pers.)
Boud. was reported by the Challenger Expedition as occurring
in Devonshire Marsh. Although this region was searched dili-
gently we were unable to duplicate the collection of this species.
The fourth species collected consisted of only two plants about
I cm. in height. While this minute species is distinct from either
of the other three collected, the species is in doubt and will prob-
ably remain so until more abundant material can be collected.

Twenty-one species of the Pezizales were collected which have
been assigned specific names. Of these one species, Ascophanus
bermudensis, is described as new. This species is most closely
related to Ascophanus sarcobius Boud., a species which was also
found to be common in the Bermudas, but the two appear to be

SEAVER: BERMUDA FUNGI 503

distinct in spore characters. Perhaps the most interesting fact in
regard to the discomycetes of the Bermudas was the collection of
several European species, which so far as the writer is able to learn
have not previously been known from North America.

One of the most interesting of these is Detonia Planchonis Boud. .
a small purple cup-fungus about I cm. in diameter. This species
was found on damp soil by roadsides and on bare soil in fields
throughout the Bermudas. While this is the commonest cup-
fungus in the islands and is large enough to be easily seen, there
is no record of the species having been previously collected either
in Bermuda or elsewhere in North America.

Another species of equal interest is Sarcoscypha minuscula Boud.
On account of its small size this species might easily be overlooked.
The species was originally described from material collected in
Portugal on dead foliage of cedar. The species while not abundant
was frequently collected and there is no record of the species having
been previously collected in North America. Among the peculi-
arities of this species are the asci, which are marked by an external
thickened ring near their apices. This gives to the ascus when
seen in profile the appearance of having two minute ears. This
structure of the ascus is very different from that of Streptotheca, in
which genus the thickened ring about the ascus projects inward
instead of outward.

Of the more common species of discomycetes, we were interested
in noting the occurrence of Pyronema omphalodes (Bull.) Fuckel on
burnt places. This species, which has proved to be of unusual in-
terest to morphologists, appears to have a very wide distribution.
The coprophilous discomycetes were found to be common and quite
abundant. A number of species of the Hysteriales and Phacidiales
were collected, five of which have received specific names.

The Perisporiaceae or ‘‘sooty moulds,”’ which are essentially
tropical fungi occurring as parasites or epiphytes on the leaves and
stems of the higher plants, were found to be quite abundant. Since
in many cases the mycelium occurred without any trace of peri-
thecia, it was impossible in such cases to make specific determina-
tions. Four species have been definitely determined.

Eight species of the Hypocreales were collected, three of which
are described as new. One of the new species is Nectria Lantanae,
a minute species which was found to be common on the dead leaves

504 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

of Lantana odorata. Whether the mycelium of this fungus attacks
the leaves while living, it was impossible to determine from field
observations. The other two new species were Calonectria Um-
belliferarum and Calonectria granulosa, the former occurring on
dead stems of Foeniculum and the latter on dead stems of Jas-
minum. Both appear to be saprophytes.

The Fimetariales or coprophilous pyrenomycetes were found
to be represented by seven species which have been found to be
determinable, and the Sphaeriales by thirteen species, none of
which are of any especial interest.

The fungi imperfecti were found here as elsewhere to be very
abundant and on account of the parasitic habits of the group will
doubtless prove to be of considerable economic importance.
Fourteen species have been specifically determined and a con-
siderable number referred to the genera only.

Two species of the Ustilaginales or ‘‘smuts’’ have been reported,
Ustilago Zeae (Beckn.) Unger, collected by Dr. Dodge, and Ustilago
Carbo Tul., reported by the Challenger Expedition.

The Uredinales or plant “‘rusts’”’ are known to be represented by
nine species, some of which have been introduced with cultivated
crops. Of this number one species, Puccinia Cladiit Ellis & Tracy,
has proved to be of especial interest according to Dr. J. C.
Arthur, who very kindly determined the plants of this group.
This species was formerly known only from the type collection
which was made in Mississippi several years ago. The Bermuda
material has added a new host and locality and also furnished
material which has enabled Dr. Arthur to complete the description
of the species in a much more satisfactory manner than would
otherwise have been possible.

The Basidiomycetes, or so-called higher fungi, although not so
abundant as in other regions, were found to be fairly well repre-
sented. The group has not been intensively studied and only
thirty-two species have been assigned specific names, including
several of those reported by the Challenger Expedition. The plants
of this group were determined by Dr. W. A. Murrill.

The slime moulds, which are often included with the fungi, were
found to be represented by a number of species, most of which
have not been critically studied.

From the studies which have been recently made on the fungi

SEAVER: BERMUDA FUNGI 505

of Bermuda, four species of ascomycetes and two basidiomycetes
have been revealed which are described as new, one variety has
been raised to specific rank and a number of European species
have been found which were not previously known from North
America. The following is a list of the species collected, so far as
they have been named:

PERONOSPORALES

Albugo candida (Pers.) Roussel. On living leaves of cultivated
radish.
MUuCORALES
Pilobolus crystallinus (Wigg.) Tode. On horse dung.
Mucor sp. On heavily fertilized soil.

HELVELLALES

Geoglossum nigritum Cooke. On rocky hillsides among mosses.

Trichoglossum hirsutum (Pers.) Boud. Reported from Devon-
shire Marsh.

Trichoglossum hirsutum Wrighttt Durand. On rocky hillsides
among mosses.

Geoglossum pumilum Winter? On damp soil in woods.

PEZIZALES

Lamprospora Planchonis (Dun.) Seaver. On damp soil. Com-
mon.

Pithya Cupressi (Batsch) Rehm. On dead foliage of Bermuda
cedar.

Lachnea pulcherrima (Cr.) Boud. On excrement of cows.

Lachnea theleboloides (Alb. & Schw.) Gill. On excrement of cows.

Ascophanus sarcobius Boud. On the excrement of cows.

Ascophanus bermudensis Seaver sp. nov.

Apothecia gregarious or scattered, at first subglobose, expanding
and becoming subdiscoid, reaching a diameter of I-2 mm., white
or more often with a delicate pinkish tint; hymenium at first
slightly concave, becoming plane, finally convex, roughened by
the protruding asci, similar in color to the outside of the apo-
thecium; asci clavate, reaching a length of 325 uw and a diameter of
35-40 mu, 8-spored; spores I-seriate or partially 2-seriate, or oc-
casionally irregularly disposed, at first smooth, becoming rough,
33-38 w X 23-25 uw; spore-roughenings assuming the form of scat-

506 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN —

tered protuberances which are enlarged outwards and giving the
appearance of protruding nail-heads, 2-3 uw long and 2 y broad;
paraphyses strongly enlarged above.

On cow dung.

TYPE LOCALITY: Near Harrington Sound, Bermuda.

DISTRIBUTION: Known only from the type locality.

The present species seems to differ from A. sarcobius Boud. in
the larger size of the spores and the difference in their markings.
Both species were collected in the same region. It is possible
that further field study will show the present species to be only
an extreme form of A. sarcobius. If so, the description and
illustrations of that species are incorrect.

Ascophanus granuliformis (Cr.) Boud. On excrement of cows.

Ascobolus stercorarius (Bull.) Schrét. On the excrement of cows.

Ascobolus immersus Pers. On the excrement of cows and horses.

Saccobolus Kerverni (Cr.) Boud. On the excrement of cows and
horses.

Lasiobolus equinus (Miull.) Karst. On excrement of various kinds.

Thecotheus Pelletiert (Cr.) Boud. On excrement of horses.

Pyronema omphalodes (Bull.) Fuckel. On damp soil where fires
have been.

Sarcoscypha minuscula Boud. & Torrend. On dead foliage of

Bermuda cedar.

Erinella rhaphidophora (Berk. & Curt.) Sacc. On old wood.

Gorgoniceps Pumilionis Rehm. On decaying wood.

Orbilia chrysocoma (Bull.) Sacc. On an old pasteboard box.

Dasyscypha earoleuca Berk. & Br. On decaying wood.

Patellaria atrata (Hedw.) Fries. On dead and decaying corn-
stalks.

Karschia lignyota (Fries) Sacc. On decaying wood.

HySTERIALES
Hysterographium lineolatum (Cooke) Sacc. On old trunks of Sabal
Blackburnianum.
Hysterographium praelongum (Schw.) Sacc. On dead wood.

PHACIDIALES
Propolis faginea (Schrét.) Karst. On old wood of various kinds.
Stictis radiata (L.) Pers. On old wood and herbaceous stems.
Stictis graminum Desm. Parasitic on stems of various grasses.

SEAVER: BERMUDA FUNGI 507

PERISPORIALES

Dimerosporium melioloides (Berk. & Curt.) Ellis & Ev. On living
leaves of Baccharts.

Meliola Cookeana Speg. On living leaves of Lippia.

Meliola circinans Earle. On living leaves of saw-grass, Mariscus
jamaticensts.

Asterina pelliculosa Berk. Reported by the Challenger Expedi-
tion on coffee leaves.

HYPOCREALES

Cordyceps militaris (L.) Link. On the pupa of an insect.

Hypocrea patella Cooke & Peck. On dead twigs of Bermuda
cedar.

Sphaerostilbe flammea (Berk. & Ray.) Tul. On bark associated
with scale insects.

Stilbocrea hypocreoides (Kalch. & Cooke) Seaver. On bark of
various kinds.

Nectria sanguinea (Bolton) Fries. On dead wood.

Nectria Lantanae sp. nov.

Perithecia superficial, minute, scattered, at first globose, col-
lapsing when dry, smooth or only minutely rough, pale orange,
often fading to nearly white in dried specimens; asci cylindric or
subcylindric, 8-spored; spores ellipsoid, I-septate, hyaline; para-
physes indistinct.

On dead leaves of Lantana odorata.

TyPE LocaALity: Near Harrington Sound, Bermuda.

DISTRIBUTION: Known only from the type locality.

Calonectria Umbelliferarum sp. nov.

Perithecia superficial, scattered or gregarious, occasionally
slightly crowded, globose or subglobose, collapsing when dry and
becoming pezizoid, bright reddish, often becoming dull when °
dry, smooth or minutely rough; asci clavate, reaching a length
of 75 and a diameter of 10 uw, 8-spored; spores usually slightly
curved, attenuated at the ends, becoming 3-septate, reaching a
length of 20-25 w and a diameter of 4 uw; paraphyses indistinct.

On dead stems of Foeniculum Foeniculum.

TYPE LOCALITY: Near Harrington Sound, Bermuda.

DISTRIBUTION: Known only from the type locality.

508 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Calonectria granulosa sp. nov.

Perithecia scattered, gregarious or occasionally crowded to-
gether in small clusters, minute, globose or subglobose, occa-
sionally collapsing, strongly granulose, bright red, finally fading
to pale yellow; asci clavate, 8-spored, reaching a length of 60 u
and a diameter of 10 uw; spores partially 2-seriate, ellipsoid, with
the ends strongly narrowed, becoming I-septate, finally 3-septate,
hyaline, reaching a length of 14-15 4 and a diameter of 4-6uy,
occasionally slightly constricted at the middle septum.

On dead stems of Jasminum.

TypPE Locality: Near Harrington Sound, Bermuda.

DISTRIBUTION: Known only from the type locality.

FIMETARIALES
Fimetaria fimicola (Rob.) D. Griff. & Seaver. On excrement of
COWS.
Fimetaria hyalina (D. Griff.) D. Griff. & Seaver. On the excre-
ment of cows.
Pleurage fimiseda (Ces. & De-Not.) D. Griff. On the excrement of
cows.
Pleurage anserina (Ces.) Kuntze. On the excrement of cows.
Pleurage vestita (Zopf) D. Griff. On the excrement of cows.
Sporormia minima Auersw. On the excrement of cows.
Sporormia intermedia Auersw. On the excrement of cows.
Chaetomium sp. On the excrement of rats.

SPHAERIALES

Rosellinia mammaeformis (Pers.) Ces. & De-Not. Reported by
the Challenger Expedition.

Rosellinia subiculata (Schw.) Sacc. On old wood of various kinds.

Lastosphaeria pezizula (Berk. & Curt.) Sacc. On decaying wood.

Hypoxylon multiforme Fries. Reported by the Challenger Ex-
pedition.

Hypoxylon investiens (Schw.) Berk. On rotten wood.

Hypoxylon fuscum (Pers.) Fries. On decaying wood.

Hypoxylon fuscopurpureum (Schw.) Berk. On old wood.

Nummularia Bulliardt Tul. On rotten wood.

Daldinia concentrica (Bolton) Ces. & De-Not. Reported by the
Challenger Expedition.

Xylaria filiformis (Alb. & Schw.) Fries. On dead leaves of
Jasminum.

SEAVER: BERMUDA FUNGI 509

Xylaria arbuscula Sacc. On sticks and rotten wood.
Poronia Oedipus Mont. On the excrement of cows.
Ophiobolus acuminatus (Sow.) Duby. On old corn-stalks.

FUNGI IMPERFECTI

Helminthosporium Ravenelit Berk. & Curt. Parasitic on Sporobolus
angustus.

Septoria oleandrina Sacc. Parasitic on leaves of Oleander.

Phyllosticta Ipomoeae Ellis & Kellerm. Parasitic on leaves of
Ipomoea.

Phyllosticta Opuntiae Sacc. & Speg. Parasitic on Opuntia.

Phoma Fourcroyae Thum. Parasitic on leaves of Fourcroya
macrophylla.

Phoma leguminum West. On old pods of Lonchocarpus violaceus.

Phoma Musarum Cooke. On petioles of banana leaves.

Pestalozzia Guepinit Desm. Parasitic on leaves of Rhizophora
Manele.

Macrosporium Solani Ellis & Martin. On old stems and leaves of
potato, Solanum tuberosum.

Sclerotitum Semen Tode. On dead leaves of some grass.

Isaria felina (DC.) Sace. On excrement of rats.

Stysanus Stemonites fimetarius Karst. On excrement of rats.

Tetraploa aristata Berk. & Br. On old wood.

Helicoma larvula Morgan. On old stems of Sabal Blackburnianum.

USTILAGINALES
Ustilago Zeae (Beckm.) Unger. On corn, Zea Mays.

UREDINALES

Nigredo proeminens (DC.) Arthur. On leaves of Poinsettia hetero-
pbhylla, Chamaesyce Blodgettit, Chamaesyce hyssoptfolia, Chamae-
syce prostrata.

Nigredo Medicaginis (Pass.) Arthur. On leaves of Medicago
denticulata.

Puccinia Lanianae Farlow. On leaves of Lantana odorata.

Puccinia Dichondrae Mont. On leaves of Dichondra carolinensis.

_ Puccinia Cladii Ellis & Tracy. On leaves of saw grass, Mariscus
jamaicensts.

Puccinia Polygoni-amphibu Pers. On leaves of Persicaria punc-
tata.

510 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Puccinia purpurea Cooke. On leaves of sugar cane, Saccharum
officinarum.
Tranzschelia punctata (Pers.) Arthur. On leaves of cultivated
peach.
Gymnosporangium bermudianum (Farlow) Earle. On foliage of
Juniperus barbadensis.
AGARICALES

Agaricus alphitophorus Berk. On small twigs. Reported by the
Challenger Expedition.

Agaricus arvensis Schaeff. On the ground in pastures.

Agaricus corticola Schum. On dead wood. Reported by the
Challenger Expedition.

Agaricus helictus Berk. On rotten leaf mould. Reported by the
Challenger Expedition.

Agaricus rhodocylix Lasch. On the ground. Reported by the
Challenger Expedition.

Agaricus tener Schaeff. On the ground. Reported by the
Challenger Expedition?

Coprinus ephemerus Fries. On the excrement of animals.

Coprinus fimetaritus Fries. On the excrement of animals.

Coriolus pavonius (Hook.) Murrill. On deciduous logs.

Coriolus sericeohirsutus (Klotzsch) Murrill. On dead branches of
cedar.

Crintpellis stupparia (Berk. & Curt.) Pat. On fallen dead sticks.

Daedalea Aescult (Schw.) Murrill. On dead trunks of deciduous
trees:

Fomes Sagraeanus (Mont.) Murrill. On dead logs and stumps.

Gymnopilus penetrans (Fries) Murrill. On dead wood.

Hirneola coffeicolor Berk. On coffee bark. Reported by the
Challenger Expedition.

Hydrocybe Cantharellus (Schw.) Murrill. On the ground.

Hydrocybe conica (Scop.) P. Karst. On the ground.

Lepiota naucina (Fries) Quél. On the ground.

Marasmius bermudensis Berk. On dead coffee wood. Reported
by the Challenger Expedition.

Marasmius minutus Peck. On fallen leaves.

Marasmius obscurus Berk. & Br. Reported by the Challenger
Expedition.

Marasmius Sabali Berk. On leaf-stalks of Sabal. Reported by
the Challenger Expedition.

SEAVER: BERMUDA FUNGI SEL

Marasmius praedecurrens Murrill. Among mosses and sticks.
Panaeolus campanulatus L. On the excrement of animals.
Pleurotopsis niduliformis Murrill. On fallen twigs of cedar.
Polyporus obliquus Fries. On dead sticks. Reported by the
Challenger Expedition.
Polyporus arcularius Fries. On dead sticks. Reported by the
Challenger Expedition.
Schizophyllus alneus (L.) Schrot. On dead wood.
Stereum hirsutum (Willd.) Fries. On dead branches.
Stereum radians Fries. On old wood.
Tyromyces graminicola Murrill. On a tuft of grass.

LYCOPERDALES

Clathrus sp. On the ground.
Geaster saccatus Fries. On the ground.

‘wid (i Bae other

oP oh ite ial

san ar ea

Ree Ho: oe

“et A tulales b aly ree )
is hd aces Lap ist

neruse Levptiryn. ab >

ae. *

ist Li) o*

e ie

a 7
Palcarrty ee ¢
t

SOME THINGS LEARNED IN MANAGING A
BOTANIC GARDEN

W.- J BrAL
Emeritus professor of botany, Michigan Agricultural College

Instead of waiting for the endowment of a botanic garden to
be managed by him, the writer, a man with no experience in such
matters, began in 1877 in a very small way to carry some of his
ideas into practice, making many mistakes, especially in reference
to treatment of hardy plants as suggested by English writers.
The mistakes were inexpensive, because the experiments were
made on a small scale; but he kept learning. To begin with, the
writer possessed some knowledge of landscape gardening, horti-
culture and systematic botany and a desire to produce a garden
which should attract the public and especially be useful to serve
as a laboratory for students. He kept studying all phases of the
subject, visiting several gardens of this country, talking with
directors and reading reports.

As the garden grew, the authorities of the college became inter-
ested, and were willing to furnish more needed money and labor.

At its best, the garden consisted of two areas, one of them on
both sides of a brook containing about two acres and a half, the
other of one acre on a gentle slope for growing grasses and other
forage crops and weeds, a total area of about three and one half
acres; the highest number of species reached was 2,500.

During an experience of thirty-three years, the following are
some of the most important things learned: labels are made of
iron galvanized, the top portion placed with one edge up instead
of sloping, this to prevent the birds from soiling them.

Now comes a very important and convenient addition to the
system of labels: a: strip of zinc with a number punched on the
upper end is thrust full length into the ground adjoining and on
the back side of the standard of the label; the numbers on the
strip of zinc are recorded in a book opposite the corresponding
name of the plant.

34 513

514 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

For about six months of the year these labels are gathered up
in bundles, each family kept by itself. When each label is taken
out a small stake is put in its place, for convenience in returning
the labels.

The label for a family is larger and the text somewhat extended.
It did not seem possible to arrange the families in order of rank,
for most of them need a change every few years. For each family
a spot was-selected of suitable size and exposure to sun and shade.
For instance, there was only one place just suited to ferns and
that could not be at one end of the list if placed to show the relative
rank. Preferably each species was given room enough to fill the
eye, a patch three feet in diameter not only for appearance, but
there is less risk of losing all of the plant in case of severe cold
weather or hot, too wet or too dry.

In some families a few trees were planted, and these were occa-
sionally cut back or a small tree substituted for a large one.

The writer soon learned that to grow violets and keep them true
to label they must be scattered not nearer than eight feet of each
other, because when mature they shoot their seeds in every
direction, some of them to a distance of ten feet. The same is
true of some species of plants of the family Euphorbiaceae, Gerani-
aceae, and species of oxalis, balsam and others.

Poison ivy and poison sumach are grown on an island not far
from the path that visitors may not touch them.

Aquatics placed in the larger pond were not equally content
with a reasonable amount of space. The most rampant one of .
the lot was Cabomba from the south. We had to draw off the
water, clean out the surplus plants and prepare a separate place
for Cabomba.

On the banks of the brook tarred paper subdued quack grass,
proving much superior to common salt.

Moles and quack grass frequently invaded the garden from the
surrounding campus. This was most successfully prevented by
the following device: dig down a narrow trench about eighteen
inches deep, leaving one wall smooth and sloping a trifle; on this
wall we placed a coat of cement mortar an inch to an inch and a
half thick, carefully filling in the dirt. Quack grass stopped then
and there; cement was preferable to hemlock boards and lasted
longer.

BEAL: MANAGING A BOTANIC GARDEN 515

Occasionally a plant, like Indian hemp or bind-weed is inclined
to roam about instead of remaining where it is given a place.
An inclosure of cement is efficient.

By repeated trials the writer has learned that rhododendrons,
azaleas, kalmias, and bluets will not flourish in the garden on
account of lime in the soil.

After three to five years, some species of Helianthus and most
kinds of mint seemed to dwindle or poison the soil. The plants
or the soil had to be changed.

After ten years, in spite of all we could do, insects disfigured
or killed nearly all umbellifers. We had to give them a rest or a
shift. Darwin and Wallace refer to similar incidents.

Why not cover top and sides over a bog with a screen and grow
a nice assortment of mosses? The writer tried it for two years
and had to admit the effort was not a success.

Spring is a busy time; for this reason we did as much work as
possible in the fall previous. At this time we would mulch with
coarse sedges and avoid scattering seeds which make trouble the
next season.

With few exceptions, unless the writer knew exactly what he
wanted, he found little satisfaction in exchanging or buying seeds;
it is very much more satisfactory to visit nurseries and gardens
when the display is good and secure living plants.

For growing weeds, grasses, and other forage plants, the writer
adopted a formal style of squares or parallelograms, five or six
feet across, where he grew about three hundred species. What
seems nicer than to grow for comparison numerous species of a
genus side by side, as for instance species of Poa, Agrostis, Poly-
gonum, Brassica, and Trifolium? Don’t do it, or you will soon
learn how much misery and perplexity can be got out of a small
piece of ground.

Of weeds, grow those unlike each other in -adjoining plats;
mix in, as clover between grasses, or place a Poa, or Panicum, or
Aristida, a Bromus, a Festuca, the small kinds among those which
are coarser.

The writer has helped half a dozen or more professors who had
admired his plats to start a weed garden or a grass garden. Inno
case was it worth while, for the species were soon in hopeless con-
fusion. Where kept pure and well grown, plats are very inter-
esting, but a few things out of place destroy confidence.

Before seeds begin to scatter, cut off the tops excepting a few
for seed and study.

In his weed garden, the writer made a start in growing some
parasitic fungi. As Gymnosporangium macropus does not grow
on red cedar in central Michigan, the writer induced our mutual
friend, Dr. Byron D. Halsted, to send him from New Jersey a
few young cedars infested with the coveted cedar apples. For
two years he made an unsuccessful attempt to infest the young
leaves of a red astrachan apple tree, demonstrating the fact that
this variety of apple is immune to this pest.

Securing red cedars from New Jersey reminds me of an incident
worth mentioning at this time: some years ago Dr. Britton, the
honored director of the New York Botanical Garden, visited the
wilds of central Michigan and noticed that the red cedars there had
bushy tops, unlike the conical tops of those in New Jersey and
surrounding country. Beside the cedars received from Dr. Hal-
sted were planted half a dozen cedars from the river bank at
Michigan Agricultural College. The two lots of cedars have
grown side by side and are now twelve feet high. The tops of all
are alike bushy, not appearing as though sheared to a conical
shape.

In conclusion, this small garden was much frequented by visitors
from far and near. The writer recalls a single comment made
by each of two men, B. T. Galloway, long the successful chief of
the Bureau of Plant Industry, ‘‘I want a garden at Washington
like this and larger.’”’ The other was Robert Warington, director
of the experimental farm so long famous for the work of Lawes
and Gilbert of England, in looking at the plats of grass, Mr.
Warington said: ‘‘ How pure they are.”

The writer had the oversight of this garden for thirty-three
years; it took less than three years for his successors to reduce the
number of species one half or more.

COOPERATION IN THE INVESTIGATION AND CON-
TROL OF PLANT DISEASES!

KarL F. KELLERMAN
Bureau of Plant Industry, U. S. Department of Agriculture

Systematic botanists and mycologists can render material aid
to the attempt to control the spread of destructive plant diseases
by more widespread distribution of information concerning the
unexpected occurrence of diseased plants in regions remote from
their usual range, and the occurrence of new plant diseases.
Cooperation among specialists now exists to a certain degree and
with the further specialization of each branch of science it will
probably become more and more the practice of the specialist in
any one field to refer related questions and material to specialists
in other fields.

This tendency, however, unfortunately overlooks the increasing
responsibilities of the federal, state, and local officials responsible
for effective inspections and the maintenance of established quar-
antines. Through more intimate contact with these officials
specialists not only contribute greatly to the efficiency and eco-
nomic value of quarantines against plant diseases, but also open
to themselves new avenues for receiving immediate information
regarding the occurrence of new diseases. The citrus canker
disease is the most striking recent example of the introduction,
gradual increase, and destructive prevalence of a distinctive disease
before its existence was recognized by plant pathologists. Inti-
mate contact between inspectors and pathological specialists would
render such an occurrence impossible.

The establishment of a more thorough plant disease survey is
desirable as well as the development of a clearing house for in-
formation regarding the occurrence and prevalence of diseases and
insect pests, but such a development will not be feasible until the
specialists themselves recognize their economic responsibility in
this work.

1 Abstract.
SLY.

Avie

“hb BES

THE NATURE OF THE INFLORESCENCE AND
FRUIT OF PYRUS MALUS

CAROLINE A. BLACK
New Hampshire Agricultural Experiment Station
(WITH PLATES 33-40)

The literature concerning the nature of the inflorescence and
fruit of Pyrus Malus is not in accord. The inflorescence is con-
sidered both determinate and indeterminate. The different parts
of the mature fruit have been variously identified and the fruit
is described under the inclusive term, pome, as originating in the
calyx, receptacle or stem, and accompanied by more or less carpel-
lary activity. The desirability of further study on this subject
being evident, the present work was undertaken by the writer.

The material for this study was collected entirely from Baldwin
trees in an orchard used for experimental purposes by the New
Hampshire Agricultural Experiment Station, the collection cover-
ing a period of more than two years in order to furnish data for
more than one growing season. From March, 1913, to July, 1915,
collections were made at intervals varying from twice a week
when vegetation was most active to every two or three weeks
when the trees were dormant. The material was fixed in chrom-
acetic acid and in the chrom-osmic-acetic acid solution prepared
according to the formula of Mottier (1), washed, dehydrated, and
embedded in paraffin. It was necessary to remove the outer
scales and immerse the buds for a few seconds in a 50 per cent.
solution of alcohol to remove the film of air on the hairs on the
inner scales in order to secure penetration of the fixative. - Sections
were cut from 17 to 25 uw and stained with Flemming’s triple stain
or with Haidenhain’s iron-alum haematoxylin. The triple stain
was preferable for detail of structure.

The following morphological study on Pyrus Malus includes
the origin and development of the flower from the incipient shoot
and the subsequent formation of the fruit. The subject matter is

519

520 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

divided into topics which are discussed in sequence as far as
possible, under the following headings:

The flower bud and its position

The inflorescence

The flower and its essential parts

Pollination and fertilization

The development of the fruit.

I. [HE FLOWER BUD AND ITS POSITION

The flower bud in the Baldwin apple is a mixed bud and de-
velops either terminally or axillarly, more frequently in the former
manner. Many so-called axillary buds are found to be terminal
upon one or more years’ growth of wood (PLATE 33, FIGURES I
and 2). The small amount of wood developed is inconspicu-
ous and has led to a rather general use of the term axillary
as applied to such buds in horticultural literature. The true
axillary bud as a rule is a very small bud found directly in the
axil of the leaf scar, and usually develops a few leaves only,
if the bud is potentially fertile. Typical axillary buds are also
shown in PLATE 33, FIGURES I, 2, and 3. A few so-called axillary
flower buds were found but the flowers formed in such buds were
few in number and of no vigorous growth, developing a little later
than the usual terminal flower buds (PLATE 33, FIGURE 7). The
few scars at the base of this inflorescence indicate that it is
really terminal and not axillary. Buds terminating long and short
shoots are shown in PLATE 33, FIGURES I, 2, and 3,as are also the
axillary buds. The difference in size between terminal buds on
one year’s growth of wood and true axillary buds is quite apparent.

The term fruit bud is well established in horticultural literature as
applying to the bud which will eventually produce fruit. The
question of distinguishing between a fruit bud and a leaf bud
naturally presents itself. The size and position of the buds may
indicate the different kinds in some fruit trees, fruit buds as a
rule being larger than leaf buds. Sometimes size indicates the
nature of the bud, as in the peach; in other cases neither size nor
relative position is indicative, as in the plums and cherries.
The size of the bud in the Baldwin is not a distinguishing char-
acter, as a comparison of the terminal buds in PLATE 33, FIGURES
1 and 2, which are leaf buds and FIGURES 3, 4, 5, and 6 which are

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 521

fruit buds, will show. The identification of these buds was
determined by dissection. A fruit bud terminates a long shoot
occasionally, as shown in PLATE 33, FIGURE 3. Usually this bud
is a leaf bud, as are the terminal buds in PLATE 33, FIGURES I and 2.

Flower buds develop on a variety of types of branches, which
have been given special names in the horticultural literature of
continental Europe. These types have been described and
figured by Eneroth (2) and Forney (3), as their recognition and
proper treatment is necessary to the successful culture of espalier-
grown trees. The various kinds of fruit-bearing branches recog-
nized by these authors are as follows: The brindille, a moderately
long slender shoot with flower buds only in the axils of the leaves;
the dard, a short stiff spine-like shoot with smooth bark and bear-
ing a terminal flower bud and axillary leaf buds; the lambourde
(FIGURE 6, PLATE 33), a short shoot with much wrinkled bark and
a terminal flower bud; the branche a fruits (FIGURES 4 and 5, PLATE
33), a lambourde or dard that has developed for several seasons, in
other words, our fruit spurs; the rameau a fruits, an ordinary branch
bearing axillary flower buds. In the apple the brindille and
rameau a fruits are rare, for the simple reason that the floral buds
are most usually terminal buds. The flower buds in the apple
are produced mostly on lambourdes or branches a fruits (PLATE 33,
FIGURES 4, 5,6). FIGURE 6 shows the beginning of the develop-
ment of a typical fruit spur, a flower bud upon one year’s growth.
FIGURE 5 shows a four-year old fruit spur and FIGURE 4 a nine-
year old fruit spur with two three-year old branches. It is evi-
dent that a fruit spur develops from the tendency of a bud to
produce fruit and to continue producing flower buds, hence the
very small wood development. The branched, wrinkled twig
becomes a fruit-bearing spur.

The growth of a flower bud is marked by an elongation of the
axis, in which more or less wood is formed and upon which the
flowers, leaves, and buds develop. This growth of stem which
was described by Forney as a bourse or ‘‘purse’’ is identified by
the numerous scars from the fruit stalks and becomes a charac-
teristic part of the fruit spur. The appearance presented in
FIGURE 2 is really due to a flower bud having developed in place
of a terminal leaf bud. The ‘purse’? which developed from this
flower bud is very conspicuous and bears the scars of the fruit

522 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

stalks. A small, dormant axillary bud is present on the “ purse”’
as well as on the shoot with the terminal leaf bud. This shoot had
developed from a leaf bud produced on the “purse” the preceding
year. The development of this so-called purse is shown in its
formation in FIGURE 8, PLATE 33, and FIGURE I, PLATE 34, and in
its maturity in FIGURES 2, 4, and 5, PLATE 33. These drawings
show that a fruit bud not only produces the flower cluster with its
subtending leaves but a small amount of wood, which varies
in different buds and becomes the “purse.’”’ From this it will also
be seen that the fruit is produced upon wood of the same year,
i. e., the stem development known as the “purse.”

It has been stated that the identification of the buds in FIGURES
I to 6, PLATE 33, was based upon their dissection. After removing
the outer scales of the buds the shape of the bud was found to
vary. If the flowers were formed, they were at once conspicuous
and altogether gave a rounded or dome-shaped appearance to the
bud, while, if only leaves were present, the end of the bud was
decidedly pointed. In longitudinal sections of very young buds
the flower bud was found to have a broad summit to accommodate
the somewhat simultaneous development of a number of parts
while the leaf bud had a more conical apex. This is shown in
PLATE 35, FIGURES I and 2 which are sections respectively of fruit
and leaf buds. Fruit buds in the Baldwin may be anticipated by
their position on the fruit spur but are identified with certainty
only by dissection.

The bud of the apple is found to be a scaly bud according to
the nature of its protection. The number of scales varies consider-
ably, depending upon the size of the bud and the stage of develop-
ment. FIGURES 2 and 3, PLATE 34, give in outline the scales of
leaf and flower buds respectively, showing the average number and
the form of the scales. Beginning with the outer, smooth, reddish
scales used for protection only, there is a gradual transition from
these to green, hairy scales with well-defined growing regions as
their apices. The growing region is seen to be flanked with two
small lobes in FIGURES 3, f, g, and /, while it has become a blade
with distinct stipules in FIGURE 2, g and h. The bud scale in the
apple is therefore a modified petiole, the innermost scales becoming
true leaves as the bud opens. ‘The flower bud is usually protected
by more scales than the leaf bud. Buds are classified by Gray (4)

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 523

according to structure as leaf, flower, and mixed buds. The flower
bud of the apple contains both flowers and leaves and is therefore,
properly, a mixed bud, as shown in the expanded buds in PLATE 33,
FIGURES 7 and 8, and PLATE 34, FIGURE I.

The time of flower bud formation is somewhat variable ac-
cording to the general conditions of growth and the state of the
apple tree and is either in the spring when growth is resumed or
the buds may develop on the second growth of the season if such
growth occurs. An interesting article on the conditions affecting
the flowering of fruit trees by Sandsten (5) states that a physio-
logical constant can be formulated from the climatic conditions
during the ten months preceding flowering. He concludes that:!
“The time of flowering in the spring of a certain variety of fruit
is dependent upon a number of causes or conditions chief among
them being, first, the number of positive temperature units
received in the spring preparatory to flowering; second the stage
of development of the flower buds as dependent upon the climatic
conditions of the summer and fall preceding the flowering; third
the fruiting of the trees,—whether light or heavy the year previous
to flowering; fourth, soil conditions and the amount of plant food
present in the soil; and fifth, the individual characteristics and
state of health of the tree and plant.’’ By the time the flowers
have advanced to the stage shown in PLATE 33, FIGURE 8, and
PLATE 34, FIGURE I, one or more well-established growing points
may be found in the axils of the lower leaves on the ‘“‘purse.”’
These growing points are the primordia of the buds for the follow-
ing year. An examination of trees in the middle of July revealed
apples approximately two inches in diameter on a well-developed
“purse.” The bud for the next year was well established. It
was partially surrounded by the petioles of two or more leaves.

The time of the differentiation of flower buds has been suggested
by Kraus (6) for Oregon by the statement that the microsporangia
pass the winter in the mother-cell stage. Drinkard (7) for Virginia
states that the primordia of the flowers were found in July and by
December the flower parts were completely formed. In February,
resting pollen-mother-cells were found. In Wisconsin Goff (8)
gives the date of June 30 for the earliest evidence of flower pro-
duction. He states that in the apple a longer time apparently

1 Page 6,

524 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

is consumed in preparing flowers than in preparing wood, and
that the flowers commenced growth about the time the wood
ceased forming.

In New Hampshire buds collected March 18, 1913, show well-
established flower parts, as seen in PLATE 35, FIGURES 3, 4, and 5.
The sporogenous tissue however was not distinct in the anthers.
By April 14, 1913, the anther wall, sporogenous tissue, and tapetum
were differentiated, as shown in PLATE 36, FIGURES 3 and 4. The
following season, 1914, the buds were a little later in their develop-
ment. The sections shown in PLATE 35, FIGURES I and 2, were
taken from buds collected April 23, 1915. No differentiation
other than the shape of the growing apex was observed, showing
that very little growth had taken place during the preceding
season. The buds for 1916 dissected on July 3, 1915, and July
20, 1915, showed no differentiation into leaf or mixed buds. If
second growth occurred in the late summer of 1915 some of these
buds might have produced floral parts, as flowers can develop on
second growth. It is evident that the time of bud differentiation
and flower formation in New Hampshire is somewhat variable.
The primordia of the flowers may or may not be established in
one growing year.

2. THE INFLORESCENCE

The inflorescence of the apple has been described by different
writers as a cyme, an umbel, a corymb, a corymbed cyme, and an
umbel-like cyme. Loudon (9) in 1844 states that the flowers in
the apple are in corymbs and in the pear in umbels on simple
pedicels. In the description of the genus Pyrus by Bentham and
Hooker (10) the inflorescence is given as a cyme and rarely a
corymb. Decaisne (11) uses the term corymb and calls the
flower stalks peduncles in his Memoir on the families of the
Pomaceae. The first six editions of Gray’s (12) Manual of
Botany describe the inflorescence in the section Malus as a cyme
simple and umbel-like. In the seventh edition of the Manual
(13), the inflorescence is given as a corymbed or umbel-like cyme
for the genus Pyrus and the flower stalks of Pyrus Malus are called
pedicels. In the Field, Forest, and Garden Botany by Gray (14)
the inflorescence is called a simple cluster or simple umbel and
the flower stalks are termed peduncles. In a revised edition
of the Field, Forest, and Garden Botany (15) the flowers are

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS) 525

described as occurring onshort, woolly peduncles. Sargent (16) in
his Manual of the Trees of North America states that the flowers
occur in simple terminal cymes with filiform deciduous bracts and
bractlets. In North American Trees by Britton (17) the flowers
are said to be clustered in simple, terminal cymes on stout, woolly
pedicels. In Britton and Brown’s (18) Flora of the Northern
United States, the flowers are described as borne in simple, terminal
cymes upon pedicels.

In Gray’s Structural Botany (4) the inflorescence is divided,
according to kind, into Determinate and Indeterminate. In a
determinate flower cluster, the axis is terminated by a flower
which corresponds to a terminal bud. If more flowers appear they
spring from axils, preferably from the highest axils and develop
later. The order of evolution is indicated by the size of the flower
buds. This type of inflorescence is also called Cymose and in
a cymose cluster the flowering is centrifugal or descending. The
terms corymbiform cyme, corymbed cyme, and umbel-like or
umbelliform cyme originate in combining qualities of indeterminate
inflorescences with determinate. The corymb and umbel are both
examples of the indeterminate inflorescence and differ chiefly in
the length of the axis or peduncle and the equality or inequality
of the pedicels.

The words peduncle and pedicel have been used interchangeably
as will be observed in the above descriptions. A peduncle is the
general name of a flower stal or branch directly terminated by a
flower. The name is also given to a more or less branched flower-
ing axis, the ultimate divisions of which are called pedicels. The
term pedicel is given to distinguish a partial flower stalk or, more
strictly, the stalk of each individual flower of an inflorescence. In
LeMaout and Decaisne’s (19) Descriptive and Analytical Botany,
the following definition of an inflorescence is found.’ “An
inflorescence in its restricted sense consists of a group of pedicelled
flowers, bracteate or not, all springing from a common peduncle
which bears no true leaves.”’

Upon dissecting the inflorescence of the apple as shown in
PLATE 34, FIGURE 4, each lateral flower is found in the axil of a
leaf or bract. The lower flowers are in the axils of leaves and
the upper are found in the axils of modified structures, or bracts,

1 Page 34.

526 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

as the series from a to e, FIGURE 4, indicates. There may be a
gradual change between successive flowers in the subtending
structure from a well-developed leaf with stipules to a very small
filiform bract, or the change may be quite abrupt. Occasionally
at the base of the terminal flower a rudimentary bract was found.
This bract sometimes contained a bud and evidently represented a
flower which failed to develop. The normal type of inflorescence
in Pyrus Malus is shown in PLATE 33, FIGURE 8. Each flower is
borne upon a pedicel, the pedicels having their origin in the com-
mon axis or peduncle. The distinction between a pedicel and a
peduncle is made clear by the irregularity shown in PLATE 34,
FIGURE I, where a peduncle, here a partial peduncle, is branched
bearing two flowers which are pedicelled. If -the inflorescence
shown in PLATE 33, FIGURE 8 is lengthened so that the flowers are
placed on an elongated axis instead of crowded on a very short
axis, a figure such as is shown in PLATE 34, FIGURE 7 would be
constructed. The dotted line represents the axis of the inflores-
cence or the peduncle. It is terminated by the pedicel of the old-
est flower. The pedicels of the lateral flowers are found in the
axils of bracts or leaves. <A solitary bractlet or a pair of bractlets
usually may be found upon the pedicels. They may be at the
base of the pedicel or irregularly placed at any point on the pedicel.
These bractlets are deciduous as are the bracts subtending the
pedicels. The number of flowers in an inflorescence varies usually
from 4 to 7.

It will be noted on old twigs at the end of the ‘“‘purse’’ where
four or five scars have been made by the loss of the apple stems or
pedicels, that a new scar has formed just beneath them. This
shows very clearly in twigs where the apples have failed to develop
and persist as shrunken mummies attached to the stem. This
condition is shown in PLATE 34, FIGURE 5. The edge of the new
scar is seen beneath the little cluster of undeveloped fruits. With
very little pressure such a cluster may be removed. FIGURE 6,
PLATE 34, shows the cluster removed and still united by the com-
mon tissue beneath. This may be considered the complete
inflorescence and the axis or peduncle becomes with age somewhat
disc-shaped.

Mention has been made of the abortive bract with its bud,
occasionally found at the base of the terminal flower. It might

‘ ’

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 527

appear that the terminal flower was in the axil of this bract and
by its more vigorous development had caused the abortion or
complete suppression of the bract and its potential bud. From
the basis of the definition, a terminal flower can not be a lateral
structure. Therefore a terminal flower can not be axillary, be-
cause an axillary flower becomes, ipso facto, a lateral structure.
A comparison of sections of developing flowers, however, shows the
unmistakable terminal character of the oldest flower from the time
of its inception toits maturity. In PLATE 35, FIGURES 4, 6, and 7
are of the terminal flower and show that it is a direct continuation
of the axis. It is more logical, from the centrifugal type of flower-
ing and from microscopic observation, to conclude that the axis
is terminated by the oldest flower and is therefore a type of cymose
inflorescence and may correctly be called a cyme.

3. THE FLOWER

The development of the flower of the apple is of two-fold interest.
It is a foundation for the subject of pollination and for the sub-
sequent formation of the fruit. Progressive stages in the develop-
ment of the apple flower have been described and figured by
many writers—Goff (8) has discussed the origin and time of
flower formation in the apple, as well as in the pear, plum, and
cherry. Drinkard (7) by means of a series of photomicrographs
presents stages in the development of the flower in the apple,
plum, pear, peach, and cherry. Quaintance (20) gives a few
figures in the development of the peach flower. Kraus (6) de-
scribes different stages in the development of apple flowers with
particular reference to the origin and nature of the fruit and
Bradford (21) shows very early stages in the flower formation
of a number of varieties of apples.

The bud in PLATE 35, FIGURE 2, shows the broad growing region
upon which the inflorescence will develop. This region consists
of ten or twelve rows of small, dense cells. These cells have large
nuclei and may be observed in various stages of cell division.
Below this meristematic tissue the cells are gradually differentiated
by their large size, irregular arrangement, and cell content. This
tissue is the pith and is characterized by many intercellular spaces
formed partly by the breaking down of one or more cells. The
density of the cells in this region varies considerably according to

528 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

the nature of the cell content. The circle of vascular tissue
surrounds this dome of pith and, branching near the summit,
sends new strands into the different structures as they are formed.
This is shown in the section in the strands on each side of the pith.
The end of the axis is early identified as a small blunt elevation
and below it are found other excrescences in the axils of small
bracts. These slight elevations are the primordia of the flowers.
The description of the development of a single flower of the inflor-
escence follows.

The parts of a flower develop from the end of the stem or the
receptacle and a typical receptacle is a rounded or flat surface on
which the floral members develop. The small elevation destined
to become a flower in the apple, is found to consist at first of a
dome of tissue which however soon becomes cup-shaped and
presents a hollowed appearance. The tissue lining this cup is
meristematic. The cells beneath this meristematic layer are a
continuation of the axis or stem on which the flower is produced.
Within this structure a vascular system is differentiated, demarking
the cortex and pith. Growth occurs on the periphery of this cup
and particularly at five points, marking the primordia of the
sepals. The origin of the sepals is of interest in relation to the
development of the fruit.

Le Maout and Decaisne (19) state that in many plants the
receptacle dilates into a cup which represents a calycinal tube,
better called receptacular cup, over which the torus is spread and
that hypertrophy of the receptacle is particularly striking in or-
chard fruits. The torus is considered the periphery of the receptacle
but the term for most authors is synonymous with the receptacle
and is so considered here. The sepals then begin their growth as
five outgrowths of the torus. According to this view the apple
flower does not possess a calyx tube, the calyx being limited to
the five sepals. The calyx therefore does not form any part of
the flesh of the apple and changes but slightly if at all as the fruit
develops.

The torus grows rapidly by intercalary growth beneath the
sepals and as growth proceeds the receptacular cup becomes more
highly developed, producing next the petals, then the stamens, and
finally the pistils. In PLATE 35 different stages in the develop-
ment of the flower are shown. FIGURE 3 is of a very young flower

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 529

with well-developed sepals. The primordia of the petals and
stamens are also shown. The intercalary growth of the torus as
well as the terminal growth of the members produced upon it
emphasizes the cup-shaped appearance, so that the floral members
are elevated considerably above the apex of the axis, which persists
in the center of the flower. In FIGURE 4 the petals, stamens, and
pistils are formed. FIGURE 5 shows two buds from an inflorescence
with the primordia of all parts established. The petals develop
in a circle within the sepals and alternate with them. Ina young
flower the tips of the scale-like petals curve over the torus, as
shown in PLATE 35, FIGURES 6 and 7, and PLATE 36, FIGURE I.
In the mature flower the tips overlap as found in PLATE 36, FIGURE
2, forming an arch over the stamens and pistils. The sepals are
lined with hairs, whereas the petalsare practically free from hairs.

The stamens next develop in three circles. The stamen first
appears as a blunt outgrowth of the torus. As the successive
circles develop, the stamen is differentiated into anther and
filament. The filament varies in length, according to the position
of the stamen. Sections of stamens in position are shown in
PLATE 35, FIGURES 3 to 7, and in PLATE 36, FIGURES I and 2. It
will be seen that the anther is conspicuous from the first. The
anther develops as a four-lobed structure as shown in PLATE 36,
FIGURES 3 and 4, which are cross sections of anthers in slightly
different stages of development. The vascular strand in the
connective appears denser than the surrounding tissue and in
each lobe of the anther a few cells are found which are larger than
the others and have dense contents. This is the primary sporo-
genous tissue in which the tapetum is early recognized. The cells
within the tapetum become the microspores or pollen grains. The
anther in FIGURE 4, PLATE 36, is a little older than that in FIGURE
3 and a little more specialization is shown in the anther wall in the
region where the longitudinal dehiscence will occur. The cells in
this portion of the epidermal layer are smaller with dense cell con-
tents and inconspicuous cell walls.

As the anther may not be formed by the end of the first year,
the pollen does not necessarily pass the winter in the pollen-
mother-cell stage as reported by Drinkard (7) for Virginia or by
Kraus (6) for Oregon. If the anther is not formed the first year
there is no resting period following the pollen mother cell stage,

530 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN.

as has been described for so many plants, and the development is
one of steady progression.

Within the innermost circle of stamens five small rounded
protuberances are formed. This last circle consists of the pri-
mordia of the five carpels or pistils. Each protuberance soon
becomes lobed as growth occurs in a circle that is not quite com-
plete, leaving a small groove. This is well expressed by Kraus! (6)
as follows: ‘‘ Directly after this very early beginning, growth does
not proceed equally in all directions from the center and form a
solid cone-like or spherical structure, but instead, about the
circumference of a circle which is not quite closed, thus forming as
further growth takes place, a narrow hood-like scale with infolded
edges.’”’ The five open or cleft pistil primordia are now found
with their openings toward the center or facing each other. The
cross section in PLATE 37, FIGURE 2, shows the position of the
pistils and the narrow opening or groove leading into the enlarged
ovarian cavity of each pistil. A longitudinal section of this
stage is found in PLATE 37, FIGURE I. The apices of the pistils
appear a little above the torus, which surrounds them. This
common tissue of the torus runs up the lengthening styles a short
distance, thus causing their apparent union, as shown in PLATE 39,
FIGURE 3. ‘The five free styles are shown in a cross section in
PLATE 38, FIGURE 6. ‘This section is made just below the origin
of the sepals and petals and shows the relative position of the
styles and stamens surrounded by the torus. Later development
of the pistils is shown in PLATE 38, FIGURE 4. The simultaneous
development of the torus surrounding the pistils prevents the
identification of the pistil as a distinct structure except at the
inner surface, where a small indentation demarks one pistil from
another. The gradual development of the pistil is shown in
PLATE 35, FIGURES, 4 to 7, and PLATE 36, FIGURES I and 2. The
openings of the pistils extend from the apex to the base, enlarging
at the base to form the ovarian cavity. The edges of the openings
become almost closed and upon these infolded edges or placentae
the ovules are produced. The five pistils are the last structures
developed by the torus and a very small portion of the end of
the axis remains. The five pistils become adjacent as growth
proceeds and the inturned edges form the boundary of a cone-like

1 Page 7.

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 53I

space directly over the remaining part of the apex of the axis.
The fact that the vegetative point of the flower-axis is not entirely
used up is observed and figured by Goebel (22) who places some
of the flowers of the Pomaceae in a ‘‘transitional position between
the perigynous to hypogynous.’! He states that ‘‘the five carpels
appear as papillae upon the hollowed-out inner surface. They
take up the whole inner margin of the cavity, but at the base
there is visible, and even at later stages it is so, the flattened
vegetative point of the flower.’”’ It will be observed in PLATE 36,
FIGURE I, that the unused portion of the axis has become slightly
elevated so that the apex is above the base of the ovarian cavities.
This elevation is caused by a slight growth of the apex of the
axis after producing the last circle of floral members, 7. e., the
_ pistils. Cell division was frequently observed in this region.
In a median longitudinal section the unused apex of the axis
presents a flattened appearance. Around this flattened area the
inner surfaces of the carpels arise somewhat gradually. The
section shown in PLATE 36, FIGURE I, Or PLATE 38, FIGURE 2, is
not a median section and the slight notch in the center is due to
the ovarian groove of the adjacent carpel. A flower is shown
just before expanding in PLATE 36, FIGURE 2. The sepals and
petals arch over the stamens and pistils. The pollen is mature in
the anthers. The styles have elongated and carry up with them
the groove to the stigma. The papillose stigmatic surface is
apparent before the flower opens. A young ovule is shown in the
ovary of one pistil. The continued growth of the torus elevates
the sepals, petals, and stamens so that they are above the ovaries.
The ovaries thus become epigynous.

One ovule develops upon each placenta of the ovary, thus two
ovules are usually found within an ovary. - Early stages in the
development of the ovule are seen in PLATE 36, FIGURES I and 2,
and PLATE 38, FIGURES I, 2, 3, and 5. FIGURE I, PLATE 38, shows
a very slight elevation upon the placenta. This rounded pro-
tuberance increases in size as shown in the next figure (FIGURE 2).
Here the section is so cut that two similar ovules are seen in
different ovaries. Below the ovule a very slight projection, the
obturator is observed, similar to that shown by Péchoutre (23) for
the pear (FIGURE 3, PLATE 38). This elevation does not appear

1 Page 568.

532 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

to be caused by the growth of any special cell but is due to the
gcowth of several cells. It results in a somewhat rounded pro-
tuberance just below the micropylar end of the ovule (PLATE 39,
FIGURES I and 5). The nucellus of the ovule is conspicuous from
the first. The ovule shows its anatropous character at an early
stage. This is seen in PLATE 38, FIGURE 3,as are also the integu-
ments. Both inner and outer integuments show on the free sur-
face of the ovule. The macrospore is apparent as a large cell two
or three cell rows below the surface in favorable sections of ovules
of this stage. A mature ovule is shown in PLATE 39, FIGURE
1. The integuments have closed over the nucellus, leaving a
narrow micropyle. A well-developed nucellar tissue surrounds
the embryo-sac, which is situated six or seven cell rows below the
nucellarcap. The integument on the inner side of the ovule is ad-
jacent with the funiculus and the latter arises just above the
spongy obturator. The fibro-vascular strand in the funiculus
terminates in a well-marked chalaza, which is particularly pro-
minent as the ovule matures. The chalaza is conspicuous in the
three ovules in FIGURE 2, PLATE 39, as shown in the cross section
at the base of the integument.

The macrospore gives rise to a seven-celled embryo-sac, the
micropylar end of which is broader than the opposite end. The
egg apparatus is well developed. The three antipodal cells are
found in the somewhat pointed end of the embryo-sac. The micro-
pylar polar nucleus and the antipodal polar nucleus fuse, forming
the endosperm or fusion nucleus.

4. POLLINATION AND FERTILIZATION

The pollination of members of the Pomaceae has been described in
two articles by Waite (24, 25) andin the apple by Lewis (26). The
subject of pollination has been studied from various points of view
and there is an extensive literature upon the subject. A discussion
of it here seems unnecessary. Flowers were hand-pollinated with
pollen from Baldwin flowers and with the pollen from other varie-
ties. The Baldwin is evidently more or less self-sterile, as a greater
percent of fruit was secured from the flowers pollinated with pollen
from other trees than with Baldwin pollen. Pollination in the
Baldwin apple is dependent more upon bees and insects than the
wind. This was indicated by the greater number of fruits set in

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 533

hand-pollinated flowers than in the flowers left to chance. A re-
cent article by Chittenden (27) emphasizes the economic im-
portance of the subject of pollination as well as the biological
significance of the problems presented by its phenomena. ‘The
stigmatic surface is papillose and when it is in a receptive state is
moist. Germination of the pollen grain takes place immediately
after pollination, and fertilization quickly follows. Fertilization
was observed in several cases. The pollen tube, which is slender,
enters the micropyle of the ovule, and apparently does not break
down tissue to reach the egg cell. Seventy-two hours after polli-
nation small embryos were found, consisting of four or more cells.

There is great activity immediately following fertilization.
The embryo-sac enlarges considerably, sometimes extending
almost the entire length of the ovule. The endosperm nucleus
divides and in the free nuclear division which follows, cell walls
are laid down and a well-developed endosperm tissue is formed.
At the micropylar end the cylindrical embryo is found on a short
suspensor. The embryo at first is rather short and thick, but
soon elongates, and is always straight. FIGURES I and 2 in PLATE
40 show two embryos in different stages of development. FIGURE
I shows the younger embryo, surrounded by the endosperm, well
up in the micropylar end of the ovule. The small uniform cells
in the periphery of the endosperm are clearly differentiated from
the more irregular interior tissue. The cotyledons and root are
well defined in the embryo. The cotyledons, which are thin and
elongated in FIGURE 2, show a well-defined vascular system. Inthe
root the central cylinder, cortex, and root cap are early distin-
guished. The blunt end of the embryo in FIGURE 2 indicates the
position of the suspensor. With the development of the embryo,
changes have been taking place in the integuments to form the
brown satiny coat of the ripe seed. Péchoutre in describing the
development of the seed in the pear observes that the nucellus
and both inner and outer integuments take part in the formation
of the seed coat. He gives in detail the changes which occur in
these tissues and states that the outer integument becomes
organized into an inner and outer zone. A comparison of the
ovule in PLATE 39, FIGURE I, and the two ovules in PLATE 40,
FIGURES I and 2, indicates the gradual change in the nucellus and
integuments of the ovule to the seed coats. While no particular

534 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN }

study was made of the seed coats in the apple, it is evident that
the nucellus and the inner integument are not as important as”
the outer integument. The zoned appearance in the latter is
shown in FIGURE 2. The outermost zone is composed of cells
which are considerably elongated and flattened. The inner integu-
ment, consisting of two or three rows of cells in the ovule, can not
be distinguished in the seed. The nucellus in the ovule occupies
all of the area within the integuments except the embryo-sac but
in the seed becomes quite inconspicuous due to the enlargement
of the embryo sac and the amount of endosperm formed. Pe-
choutre describes the nucellus as recognizable by a cutinized strip
or band. This is conspicuous in the apple as the dark wavy line
in FIGURE 2, PLATE 40, and its origin can be distinguished in
FIGURE I, PLATE 40. The endosperm is practically exhausted
by the time the seed is mature.

5. THE DEVELOPMENT OF THE FRUIT

The activity following fertilization is not confined to the embryo
and ovule but extends to the ovary and torus, the further develop-
ment of which gives rise to the fruit called in the case of the
apple, a pome. The word pomum is used several times by Pliny
(28) but referred then to many kinds of fruit, such as apples,
cherries, nuts, berries, figs, and dates. Its application was apt
only for round fruits. The fruit of the apple is now called a
pome. Hence there is the Pomaceae or apple family or tribe.
Conversely, the definition for a pome in general terms as found in
the glossary! of Gray’s Manual 7th ed. reads, ‘‘ Pome,—a kind of
fleshy fruit of which the apple is the type,’’ or in Jackson’s Glos-
sary” of Botanic Terms (29) ‘‘ Pome,—an inferior fruit of several
cells of which the apple is the type.’’ More specific descriptions
are given by Gray in the text of the 7th edition of the Manual?
as—‘‘Fruit a large, fleshy pome with 2—5 papery or cartilaginous
cells imbedded in the flesh.” The genus Pyrus in Gray’s Field,
Forest and Garden Botany’ is characterized as ‘‘a genus made to
include a great variety of plants, agreeing in the cartilaginous
parchment-like or thin-walled cells that contain the seeds. In the

1 Page 881.

2 Page 206.

* Page 457.
‘Page 161.

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 535

apple the fruit is umbilicate at both ends. It is various, but always
holding the calyx lobes upon its apex.”’

It is evident from the literature that the structure of the apple,
pear, and quince has been the object of much study. Lindley
(30) describing the Pomaceae states that as the fruit ripens, the
calyx and ovaries increase simultaneously in size. The carpels
become fleshy and form with the calyx a five-celled fruit with
cartilaginous or chartaceous endocarp in Pyrus and osseous endo-
carp in Mespilus—and to these the term pomum may be strictly
applied. The fruit is absolutely inferior, the carpels cohering
with the calyx and each other by their whole surfaces.

De Candolle (31) describes the fruit of the Pomaceae as re-
enforced or consisting of the union of the calyx tube and carpels.
Decaisne (32) gives a longitudinal section of the fruit, showing
the position of the receptacular cup and ovaries. Carriére (33)
gives a cross section of the fruit in reference to the core. Barry
(34) describes the pomes or kernel fruits as accessory fruits. In
Le Maout and Decaisne (19) directions are given to halve an
unripe pear or apple when five carpels are found, forming 5 two-
ovuled cells, surrounded by a fleshy mass. ‘The so-called calycine
tube (better called receptacular cup) has closely enveloped them,
and agglutinated them by their lateral faces, but has left their
inner faces free. The parenchyma of the receptacle is enormously
increased in bulk to envelop the ovaries; the remains of the sepals
and stamens are carried up by the expansion of the receptacle.
The receptacular tube encloses the carpels. A pome is considered
an accessory fruit and is defined as a berry composed of many,
usually five, cartilaginous carpels, forming five cells and united
to the receptacular tube;—examples are the apple, pear, and
quince.

The word receptacular cup gives way to perhaps a better ter-
minology in the use of the word hypanthium or hypanthial re-
ceptacle, which is a flower axis or receptacle developed mainly
under the calyx—according to Gray (4). He states in describing
the flower of Calycanthus that! ‘‘the receptacle, instead of convex
or protuberant is here concave, and has grown up around the ovary
which is free from the cup but immersed in it, as in the hawthorn,
A comparison with a rose-hip, an apple and a pear much strength-

1 Page 214.

536 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

ens this interpretation which is rather largely adopted at this day,
at least theoretically. It was perhaps first proposed by Link who
introduced the appropriate name of Hypanthium.”’ Sturtevant
(35) sums up the fruit of the apple as the core, consisting of the
carpels, and the edible portion, or the calyx, which is adherent to
the exterior of the ovary. Bessey (36) defines a pome as the en-
larged and fleshy calyx cup enclosing the papery carpels. Stras-
burger (37) describes the apple as a form of berry and considers
it a spurious fruit composed of the carpels which are adnate to
the wall of the receptacle. In the Handbook of Practical Botany
(38) he describes the apple as a fleshy indehiscent fruit. The
ovary is considered five-celled and is immersed in a hollowed
flower stalk, a so-called hypanthium, or receptacular tube and is
adnate to this. The thickening in the endocarp is compared with
the shell of a plum stone. Van Tieghem! (39) describing the fruit
of the Rosaceae says: ‘‘The floral receptacle develops sometimes
at maturity into a fleshy and edible substance (strawberry).
In other cases it is the tube resulting from the concrescence of the
three external parts which grows and forms around the fruit, a
dry envelope (sanguisorba, agrimonia, etc.), or fleshy (rose);
in the latter case if the carpels are concrescent with this fleshy
tube and if they themselves become drupes, we have a fruit of
which the fleshy portion has a double origin, belonging as regards
the external part to the tube formed by the concrescence of the
external parts and as regards the internal part to the pistil itself;
it is in part a false fruit (pear, quince, hawthorn, etc.).’’ Sorauer
(40) has a diagram of a young flower of the apple on page 219 of
the Popular Treatise on the Physiology of Plants, and in the text
states that the edible portion of the apple consists of the hollowed
axis or receptacle and that the apple is the cortical tissue of a
succulent shoot.

The exact nature of the structure of the fruit of the apple is
obtained from a study of the development of the parts, as has
recently been done by Kraus in his paper, The Gross Morphology
of the Apple. Kraus states in his summary on page 10 ‘‘that the
initiat development of an epigynous fruit as typified by the apple
(Malus), and of a perigynous fruit such as the plum (Prunus),
are the same. Subsequent growth in the former, proceeds across

1 Page 1663.

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 537

the entire torus and carpels conjointly; in the latter, such growth
is intercalary; the carpels and that part of the torus which bears
the sepals, petals, and stamens, maintain an independent growth.”
A conclusion substantially similar to that of Kraus has been
reached by the writer with the exception of the interpretation of
the term intercalary.

Jost (41) defines intercalary growth as the interpolation of a
new region between two zones which are already fully developed,
giving as an example, Oedogonium. Sachs (42) cites the growth
at the base of the internodes of grasses, the production of new
laminae in Laminaria and the development of the inflorescence
in the fig as examples of intercalary growth.

In discussing terminal and intercalary growth, Van Tieghem!
states that if growth is exclusively terminal, the parts of the
structure are superposed gradually from base to summit according
to age. The formation is thus basifugal. When growth is exclu-
sively intercalary it may occur equally in all parts of the structure
at the same time or it may be localized in a certain transverse
zone. In the first place all parts are of the same age, their forma-
tion is simultaneous. In the second case the parts are of different
ages and successive. Depending on the position of the interca-
lary growth, we may have: growth towards the apex, or basifugal
growth; growth towards the base, or basipetal growth; or, growth
may be intermediate, when it is said to be mixed. Finally if both
terminal and intercalary growth occur at the same time, which is
very frequent, the two results are superposed. The apex produces
the parts at first in basifugal order, then, in these parts are inter-
calated the new ones which have formed following the simultane-
ous method or one of the other three.

Different zones of growth may be distinguished in very simple
plants according to Pfeffer? (43), who states that ‘“‘not only apical
and intercalary vegetative zones, but also zones in which only
growth in length is active, may be present in trichomes, and
also in the filaments of algae and fungi. Moreover, the remark-
able forms assumed by unicellular diatoms and desmids suffice
to indicate that localized differences in growth are possible even
in cells which retain their embryonic character.’’

1 Page 34.
2 Page 10.

538 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Vines (44) on page 17 of his Textbook on Botany states: “‘One of
the most remarkable instances of an intercalary growing-point is
that occurring in connection with the development of hollow, more
or less tubular structures (e. g., inferior ovaries, ‘calyx-tube’ of
Rosaceae, gamopetalous corollas, inflorescence of the fig, pitchered
leaves of Nepenthes, Utricularia, etc.). Taking the case of a
hollow floral receptacle (whether inferior ovary or ‘calyx-tube’)
when the apical growth of the axis is arrested, a zone of embryonic
tissue lying close behind the apex gives rise to a projecting ring
of tissue, which by continued basal growth, becomes a tube en-
veloping the apex of the shoot.’’ And again on page 495: “Ina
great number of plants the perianth and androecium are raised by
the intercalary growth of a lower portion of the axis (as repre-
sented by the outer portion of the torus) and stand on a circular
rim surrounding the apex of the axis which lies at a lower level.
Of this condition two different forms occur: in the one, the carpels
are inserted in the depression at the apex of the axis, and there
form one or more ovaries free from it, primarily at least, though
they may subsequently become adherent to it; in such cases as in
the rose and apple, the flower is said to be perigynous.”’

Goebel in describing the development of the fruit in the apple
states that an ordinary perigynous flower would develop if the
carpel alone, by intercalary growth produced the ovary. He
attributes the formation of the ovarian cavity to growth involving
‘both the flower axis and the base of the carpels which quite
cover its insides.’’!

The growth of the carpel in the apple as an established organ
has no relation to the further growth of the structure which pro-
duced it, save as they may develop conjointly. Intercalary
growth occurs in both simultaneously. Following then the
principles elaborated by Van Tieghem and the various examples
given by other authors, intercalary growth may be distinct with
the interpolated tissue clearly limited by zones of mature tissue
or it may occur with terminal growth and according to either the
simultaneous or successive development complex growth relation-
ships result. The development of the flower of the apple is the
result of both terminal and intercalary growth. The excessive
growth resulting in the fruit is due chiefly to the intercalary growth
of the torus.

1 Page 568.

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS) 539

The apple fruit is the result of a combination of the growth of
the inferior ovaries and the torus of the receptacle. The identi-
fication of the various parts of a mature fruit is made by com-
parison with the origin and development of these parts in the
flower and immature fruit. It has been shown that the sepals,
petals, stamens, and pistils arise successively from the meriste-
matic surface of the concave torus. The great growth of the
torus and underlying parenchyma elevates the circles of sepals,
petals, and stamens in succession, so that they gradually assume a
position above the pistils—PLATE 35, FIGURES 3 to 7; PLATE 36,
FIGURES I and 2. The pistils thus become inferior. A com-
parison of the developing flower and the immature fruit (PLATE 37,
FIGURES I and 2; PLATE 38, FIGURES I to 6; PLATE 39, FIGURES
I to 5) furnishes the basis for the following description of the
formation of the fruit. The five pistils in the flower (PLATE 35,
FIGURES 3 to 7) arise from the embryonic tissue of the torus
around the apex of the axis which is not entirely used up. Each
pistil is united to its neighbor by the tissue of the torus, thus
forming a continuous ring, except that part becoming the style.
Sections cut near the apex of the fruit show the styles still united
peripherally, but distinct centrally, with the grooves! leading to
the ovarian cavities (PLATE 39, FIGURE 3). Sections cut at a higher
point show the five now distinct styles with their grooves centrally
faced (PLATE 38, FIGURE 6).

The parenchymatous tissue just beneath the meristematic end
of the axis and the organs produced upon it becomes the pith. As
the torus becomes more concave the pith area also conforms to
this shape. This has been shown in a diagrammatic way by
Kraus. The developing pistils thus become enveloped by the
increasing torus with which they have always remained united
(PLATE 36, FIGURES I and 2; PLATE 37, FIGURES I and 2; PLATE 38,
FIGURES 4 and 5). That part of the section properly pistil is
clearly distinct from that which is torus as shown by the finer cells
and by the network of small vascular bundles outlining each carpel
as found in FIGURES 4 and 5, PLATE 38.

Growth proceeds rapidly in the pistil and torus, following the

1In the apple the gynoecium is more sensitive to frost than the other floral organs.
This greater susceptibility to cold has frequently been attributed to the sensitiveness

of these parts, whereas it seems more reasonable to explain it as due to the exposure
occasioned by the structure of the pistils.

540 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

stimulus of fertilization. The wall of the ovary develops as
two distinct layers. The inner, or endocarp, composed of rela-
tively few cells, becomes firm and leathery or, as frequently de-
scribed, cartilaginous. The outer, consisting of mesocarp and
exocarp remains soft and pulpy, and is traversed by numerous
small fibro-vascular bundles. The innermost edges of the carpel-
lary wall come together forming a drupe-like suture, while the
outer tissues lose their identity and become _ indistinguishable
from the torus. Thus the conditions of a drupe are fulfilled and
if the ovary of the apple were superior, developing free from the
torus, the resulting fruit would be a close approach to a true drupe.
As it is, the ovaries are inferior and are embedded in the torus
which grows with the carpels. This is shown in the three sections
of fruits in FIGURES 2, 4, and 9, PLATE 39. The demarcation of
the various tissues can be seen in FIGURE 2 with the exception of
the endocarp, which is only distinguished as the darkened border
of the ovarian cavity. The exocarp is limited by the series of
small fibro-vascular bundles appearing in the figure as a row of
small dots. The tissue next in position extending from the
exocarp to the primary vascular bundle is conspicuous by the
absence of all vascular tissue. This zone of tissue may be called
the pith of the apple and is continuous with the pith of the stem.
The cortex or remaining tissue is separated from the pith by ten
primary vascular bundles.

The vascular structure of the apple has long been studied.
Ten primary strands are described in Miller’s (45) Garden
Dictionary as occurring very regularly in the apple, one at the
point of each cell of the ‘‘capsule’’ and one in the middle between
the other five. Loudon (9) makes a somewhat similar statement,
adding that the bundles tend toward the calyx. Decaisne (11)
in a figure of a longitudinal section of the apple shows the primary
vascular strand with the dorsal strand of the carpel arising from it.
Recently McAlpine (46, 47) has worked out the fibro-vascular
system of the apple and pear. In the apple McAlpine shows ten
primary vascular bundles supplying the ‘‘flesh’”’ and secondary
branches supplying the ‘“‘core.’’ In the pear, he states that as
each one of the five primary bundles approaches its corresponding
carpel, it gives rise to an internal branch which passes along the
dorsal or outer face of the carpel, while the main portion of each

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS °¢ 541

bundle is continued beyond to the blossom-end of the fruit.
There are also five alternating bundles which diverge a little higher
up than those in the preceding and each one passes between two
carpels, giving off an internal branch to the inner or ventral face
of the carpel. The vascular system in the apple is shown diagram-
matically in PLATE 33, FIGURES 9 and 10. Ten primary vascular
bundles demark the cortex and pith regions in the apple. Five of
these bundles are found directly opposite the carpels and the
other five alternate with them. The carpellary vascular system
arises from these primary strands. A dorsal strand supplying the
exocarp arises from each of the primary bundles opposite a carpel.
A ventral strand which eventually branches, producing two strands,
arises from the alternating primary bundle. These strands pass
through the placentae of the carpels and again branch to supply
the ovules. The dorsal and ventral strands eventually anasto-
mose in the region of the style. The primary strands branch
repeatedly to supply the sepals, petals, and stamens, and the
tissue of the cortex. The ten primary bundles finally anastomose
in a very small ring at the apex of the greatly enlarged fruit.
In the longitudinal section in FIGURE 9 one of the primary vascular
bundles is shown with the dorsal bundle of the carpel which arises
from it. One of the ventral strands extends along the inner
surface of the carpel and sends a branch to the ovule. The anasto-
mosing of the dorsal and ventral strands is indicated. The
different regions of the fruit may be identified in the drawing as
follows (a) representing the unused portion of the axis of the
flower; (6) the exocarp of the carpel separated from (c) the pith,
by the dorsal vascular bundles; and (d) the cortex, which is dis-
tinct from the pith and is outlined by the primary vascular bundles.
The same regions are indicated by similar letters in the cross
section in FIGURE 10. It will be observed that the five primary
vascular bundles opposite the carpels are in a circle of a slightly
larger diameter than the circle of the intermediate bundles. The
small row of dots demarking the exocarp of the carpel represents
the distribution of branches from the large dorsal bundle of the
carpel. The two ventral bundles in each carpel are inconspicuous.
Within each carpel two ovules are shown. The dorsal primary
bundle and the suture formed by the infolded edges of the carpel
lie on radii passing through one of the outermost primary vascular

542 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

bundles. Radii passing through one of the inner primary vascular
bundles would lie in the small strip of pith tissue separating one
carpel from another, and would pass between the two ventral
vascular bundles.

In conclusion, it will be observed from the literature that the
identification of a pome has been along two lines. One was to
determine the origin and nature of the fleshy portion and the
other was to determine the rdle of the carpel in the formation of
the fruit. The receptacular origin of the fleshy portion has been
quite generally accepted. The development of the carpel has
not been so generally discussed, although the coherence of the
receptacle and carpels has been emphasized. It will be recalled
that Van Tieghem described the similar fruit of the pear and
quince as a false fruit and considered the carpels drupes. Kraus!
defines the fruit as follows: ‘“A pome is to be regarded as con-
sisting of one to several drupe-like fruits more or less intimately
connected with a fleshy torus, on and within which they are
borne.’’ The apple is thus shown to be the result of excessive
growth on the part of the torus, surrounding and embedding in
it the carpels. The torus originates in the receptacle of the
flower and results in the flesh of the fruit. The carpels taken
singly correspond to drupes. The fruit of the apple may then be
considered as a reenforced or composite fruit consisting of one
to several drupe-like fruits embedded in a fleshy torus and is
called a pome.

SUMMARY

I. The size of the fruit bud in the Baldwin apple is not a dis-
tinguishing character.

2. Fruit buds may occur in various positions such as terminating
a long or short shoot or on a structure known as the fruit spur.
The fruit bud is rarely axillary.

3. Fruit buds in the Baldwin apple may be anticipated by their
position on the fruit spur, but are identified with certainty only
by dissection.

4. The growth of the fruit bud is characterized by an elongation
of the axis called the ‘‘purse,’’ in which more or less wood is
formed and upon which the flowers, leaves, and buds develop.

5. The bud scales are modified petioles.

1 PPage 9.

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 543

6. The time of bud differentiation and flower formation in New
Hampshire is somewhat variable. The primordia of the flowers
may or may not be established at the end of the growing season.

7. The inflorescence in the apple is a simple cyme, consisting of
usually four to seven pedicelled flowers upon a very short peduncle.

8. The parts of the flower develop in succession from the torus.
The greater growth of the cells in the periphery of the torus
results in a cup-shaped structure, thus elevating the sepals, petals,
and stamens above the epigynous carpels. The apex of the
axis is not completely used up in the production of the flower
parts.

9g. The inferior ovaries in the apple are embedded in the torus,
which grows with the carpels. The mesocarp and exocarp of the
carpel become fleshy, whereas the endocarp becomes cartilaginous
or papery.

10. The torus is the receptacle of the flower and by excessive
growth produces the flesh of the fruit, in which a well-defined pith
and cortical layer can be seen.

11. Ten primary vascular bundles demark the cortex and pith
regions in the apple. The carpellary vascular system arises from
these strands.

12. The fruit of the apple may be considered a reenforced or
composite fruit consisting of one to several drupe-like fruits
embedded in a fleshy torus and is called a pome.

For valuable help and criticism, the writer wishes to express
her sincere appreciation to Dr. O. R. Butler, who suggested this
study, and whose constant advice and assistance made the photo-
micrographs possible.

LITERATURE
1. Mottier, D. M. Beitrage zur Kenntniss der Kerntheilung in den
Pollen-Mutterzellen einiger Dikotylen und Monocotylen. Jahrb.
Wiss. Bot. 30: 169-204. 1897.

. Eneroth, O. Handbok I, Svensk Pomologi, 172-180. 1864.

. Forney, E. La taille des arbres fruitiers. 1: 21-23. 1907.

. Gray, A. Structural botany, 1: 40, 144, 214. 1879 [ed. 6].

. Sandsten, E. P. Conditions which affect the time of the annual
flowering of fruit trees. Wisconsin Exp. Sta. Bull. 137: 1-7.
1906. ¥

6. Kraus, E. J. Gross morphology of the apple. Oregon Agr. Coll.

Exp. Sta. Res. Bull. no. I, part I. 1913.

ob WwW dN

544 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

7. Drinkard, A. W. Fruit-bud formation and development. Ann.
Rep. Virginia Agr. Exp. Sta. 1909-1910: 159-205.

8. Goff, E.S. The origin and early development of the flowers in the
cherry, plum, apple and pear. Ann. Rep. Wisconsin Agr. Exp.
Sta. 16: 289-303. 1899.

9. Loudon, J.C. Arboretum et fruticetum britannicum. 2: 880-894.
1844 [ed. 2].

10. Bentham, G., & Hooker, J. D. Genera plantarum. 1: 626. 1865.

11. Decaisne, J. Mémoire sur la famille des Pomacées. 153. 1875.

12. Gray, A. Manual of botany. 1848-1890 [ed. 1-6].

13. Robinson, B. L., & Fernald, M.L. Gray’s New manual of botany.
1908.

14. Gray, A. Field, forest, and garden botany. 1869.

15. Gray, A. Field, forest, and garden botany. 1895.

16. Sargent, C.S. Manual of the trees of North America. 1905.

17. Britton, N. L. North American trees. 1908.

18. Britton, N. L., & Brown, A. An illustrated flora of the Northern
United States, 2: 1913 [ed. 2].

19. Le Maout, E., & Decaisne, J. Descriptive and analytical botany.
1876 [Eng. trans.].

20. Quaintance, A. L. The development of the fruit buds of the peach.
Thirteenth Ann. Rep. Georgia Exp. Sta. 13: 349. 1900.

21. Bradford, F.C. Fruit bud development of the apple. Oregon Agr.
Coll. Exp. Sta. Bull. 129. 1915.

22. Goebel, K. Organography of plants, Part 2. English edition by
Balfour, 568. 1905.

23. Péchoutre, F. Contribution a l’étude du développement de Il’ovule
et de la graine des Rosacées. Ann. Sci. Nat. Bot. VIII. 16: 1-158.
1902.

24. Waite, M. B. The pollination of pear flowers. Div. Veg. Path.
U.S. Dept. Agr. Bull. 5. 1895.

25. Waite, M. B. Pollination of pomaceous fruits. Yearbook Dept.
Agr. 1898: 167. 1899.

26. Lewis, C. I., & Vincent C. C. Pollination of the apple. Oregon
Agr. Coll. Exp. Sta. Bull. 104: 1-140. 1909.

27. Chittenden, F. J. Pollination in orchards. Ann. Applied Biol. 1:
37-42. I914.

28. Pliny, C. Naturalis historia.

29. Jackson, B.D Glossary of botanic terms. 1905 [ed. 2].

30. Lindley, J. Observations on the natural group of plants called the
Pomaceae. 1820.

31. Candolle, A. de. Introduction a l'étude de la botanique. 1835.

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 545

32. Decaisne, J. Le jardin fruitier du Muséum, 1: 39. 1858.

33. Carriere, E. A. Etude générale du genre pommier et particuliére-
ment des pommiers microcarpes ou pommiers d’ornement. 1883.

34. Barry, P. The fruit garden. 1852 and 1889.

35. Sturtevant, E. L. Seedless fruits. Mem. Torrey Club 1: 141-185.
1890.

36. Bessey, C. E. The botany of the apple tree. Ann. Rep. Nebraska
State Hort. Soc. 1894.

37. Strasburger, E., Noel, F., Schenck, H., & Schimper, A. F. W. A
textbook of botany, 563-564. 1903 [Eng. trans.].

38. Strasburger, E., & Hillhouse, W. Handbook of practical botany.
Aas 1911 fed. 74.

39. Van Tieghem, P. Traité de botanique, 34 and 1663. 1891 [ed. 2.]

4o. Sorauer, P. A popular treatise on the physiology of plants. 1895
[Eng. trans. ].

AI. Jost, L. Plant physiology, 261. 1907 [Eng. trans.].

42. Sachs, J. v. Physiology of plants, 467. 1887 [Eng. trans.].

43. Pfeffer, W. Physiology of plants, 2: 10. 1903 [Eng. trans.].

44. Vines, S. H. A students’ textbook of botany, 17 and 495. 1896.

45. Miller, P. The gardener’s and botanist’s dictionary. 1807.

46. McAlpine, D. The fibro-vascular system of the apple (pome) and
its functions. Proc. Linn. Soc. New South Wales 36: 613-625.
TOUT:

47. McAlpine, D. The fibro-vascular system of the pear (pome).
Proc. Linn. Soc. New South Wales 36: 656-663. I9II.

Description of plates 33-40

PEATE 33

1. Shoot with two short lateral branches. The terminal buds are leaf buds. A
typical axillary bud is present. .

2. Three-year-old shoot, the axis of which has ceased to elongate owing to the de-
velopment of a flower bud the second year. A strong lateral shoot has growa out of
the ‘‘purse’”’ and a weaker one from the three-year-old wood. The terminal buds and
axillary bud are leaf buds.

3. Shoot with a terminal flower bud.

4. Nine-year-old fruit spur bearing three-year-old branches. The scars from the
pedicels of the fruit may be seen upon the “purses.”

5. Four-year-old fruit spur.

6. A fruit bud is shown upon one year’s. growth, the beginning of a typical fruit
spur.

7. So-called axillary flower bud. In the specimen figured the flowers were few in
number and lacked vigor, developing late.

8. Typical apple inflorescence.

546 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

9g. Diagrammatic longitudinal section of the fruit, showing the vascular system.
(a) The unused portion of the axis of the flower, (b) the exocarp and mesocarp of the
carpel, (c) the pith, (d) the cortex.

10. Diagrammatic cross section of the fruit, lettering as in FIGURE 9. The rows of
small fibro-vascular bundles surrounding the carpels on their outer faces form the
boundary line between carpellary and torus tissue. The primary fibro-vascular bundles
occur in two circles of five each. The bundles of the outermost circle occupy positions
opposite the carpels, those on the inner circle positions between the carpels.

PLATE 34 .

1. A slightly irregular inflorescence showing the distinction between a pedicel and
a peduncle which in this case is a partial peduncle.

2. A series of bud scales from a leaf bud showing the petiolar origin of the scale.
a, Outermost scale to innermost scale, /.

3. Aseries of bud scales from a flower bud. a, Outermost scale to innermost scale, h.

4. Individual flowers of an inflorescence with the leaves or bracts which subtend
them. a, Oldest flower to youngest flower, e.

5. Acluster of mummied fruits. The peduncle is becoming separated from the stem
which bore it.

6. The cluster shown in FIGURE 5 removed. The inflorescence is abjointed as a
whole by the common tissue, the peduncle.

7. Diagrammatic drawing of an inflorescence. The dotted line is the axis of the
inflorescence or peduncle from which arise the pedicelled flowers.

PLATE 35

1. Longitudinal section through the apex of the leaf bud with the same general
structure as the fruit bud.

2. Longitudinal section of the growing apex of a flower bud. The pith is crowned
by the layer of meristematic tissue.

3. Longitudinal section of a young flower with the calyx well developed and the
primordia of the petals and stamens established.

4. Longitudinal section, showing the primordia of all parts present. The pistils
are the last organs developed.

5. Longitudinal section of two young flowers, showing the ovarian cavity in two
carpels and the unused central portion of the axis.

6. Longitudinal section of a flower. This section shows clearly how the torus
becomes hollowed as the successive circles of the flower parts develop. The unused
portion of the apex of the axis is shown. The ovarian cavity is seen in two carpels.

7. A little later stage than the preceding. The styles have developed and extend
slightly above the torus. A primary vascular strand is shown on either side, supplying
the sepals, petals, and stamens.

PLATE 36

1. Longitudinal section of a flower, showing petals arching over the stamens. The
well-developed anthers and young ovule primordia are shown. The unused portion
of the axis is conspicuous.

2. Longitudinal section of a flower just before expanding.

3. Cross section of a young anther, showing the differentiation of the sporogenous
tissue.

4. Cross section of a young anther. The point at which dehiscence will occur is
clearly indicated between the pollen sacs.

Mem. N. Y. Bor. GARDEN VOLUME VI. PLATE 33

GoA. 6: det}

HELIOTYPE CO. BOSTON

Biack: Pyrus MALusS

™‘

— oe

a oe ee
: 7)

Mem. N. Y. Bor. GARDEN VoL_uME VI, PLATE 34

C A.B del
HELIOTYPE CO., BOSTCN

BLAcK: Pyrus MALus

Meo. N. Y. Bor. GARDEN VoLuUME VI, PLATE 35

C. A. B. photo
HELIOTYPE CO., BOSTCN

BLAcK: Pyrus MALuS

VoLuME VI, PLATE 36

Meo. N. Y. Bor. GARDEN

A. B. del

HELIOTYPE CO., BOSTCN

Biack: Pyrus MALus

Sie i i
‘4 , ; i
Vi AWA, CAN ("i }
‘ Ad ke r

i : ‘ta rae
‘ wae ey A
Airy NG ene
¥ ; Dae We A
1
i
i
|
;
Ue: }

a ee or Se ee eee eee

| A) ee he we te

VOLUME VI. PLATE 37

Mem. N. Y. Bor. GARDEN

C. A. B. photo

BOSTON

HELIOTYFE CO.

Pyrus Matus

BLACK:

PLAT

VOLUME VI.

HELIOTYFE CO. BOSTON

Pyrus MALus

BLACK :

Mem. N. Y. Bor. GARDEN

zd
Foo

A
*
=~
D

1 Stes
Wei
apes

C. A. B. photo

; ;
5 .
mal
1 io “
|
j
(
}
:
'
7
6
-
*

i
hg |

; j ; he

Ad
5 i

PLATI

VOLUME VI.

Bor. Garni

ING SCs

Mem.

yd,

BOSTON

HELIOTYPE CO.

C. A. B, photo

Pyrus MALus

BLACK :

beiire: {7 f
} ty AG bi ),
“ *

, ny oh:

ae
pti
Pa
f } i
| Ae :
| ed i A
A J Py yt i i
‘
H | Yi ' 1
) Pal? ‘ ’
. ¥ a *
® ii \ tp
e% ' a a eee
i
Jj a
° :
‘ ‘
re
| a
’ -
, il}
, f] ‘
1 4
:
as .
t ‘ ‘ 5

i ™

Mem. N. Y. Bor. GARDEN VoLuME VI. PLATE 40

C. A. B. photo
HELIOTYPE CO., BOSTON

Pyrus MALuUS

BLACK

Ub ae!

| oy Te a eet
eran Yer a ‘
j hy i BA “s ny oe r ca i
¥ Pia | Ln rT ; th | ti VF I
adie : ye ial ris
roe 1 A Vein ae i sary F he
; in ‘ =| i $A * if Le r

yy "i
’ )
‘ ‘ J, iv ( j
Pan “a |
i]
!
7 wf
* Ve ’ :
$ : _
*
bi 1
‘
x .
t Te! yy cm ¥/
t ) ae tee
n ®
rt ik FA
y bal ys
7 p’ Y )r ”
y
i
* i
i
a n
SS
‘
-
‘
i
‘
‘
a ‘
¥, 4
it’s
‘
. i A
¢
. FE
‘
7
ne : a’
-
=. i
{
. =o
*
i
‘
i
it

j . As een) . '
Vine Cae j j
ee a Tv) ) Me are ee re |

BLACK: INFLORESCENCE AND FRUIT OF PYRUS MALUS 547

PLATE 37

1. Longitudinal section of a young flower, showing the sepals, petals, and stamens
elevated above the carpels which are embedded in the torus. The ovarian cavities are
indicated.

2. Cross section of a young flower showing the five carpels and the ovarian cavity
in each formed by the infolding of the edges of the carpel. The small dense cells demark
the carpellary tissue from the tissue of the torus. The ten primary vascular strands
are found in the latter.

PLATE 38

1. Longitudinal section of a young flower, showing the origin of the ovule.

2. Median longitudinal section, showing the unused portion of the apex of the axis
of the flower with a developing carpel on either side of it.

3. Longitudinal section, showing the anatropous ovule and the inner and outer
integuments.

4. Cross section of a young fruit. The demarcation of the carpels is shown by the
outline of small vascular strands around each one. A slight indentation is present in
the common tissue between two.carpels in which the ventral vascular strands lie em-
bedded. The dorsal strand of each carpel is also shown as well as the ten primary
strands demarking the pith and cortex regions.

5. Cross section similar to FIGURE 4, but showing two ovules in each ovary.

6. Cross section of fruit, showing the position of the parts above the torus. The
five styles are free.

PLATE 39

1. Longitudinal section of a mature ovule, showing the integuments, nucellus and
embryo-sac. The obturator is the projection just below the ovule.

2. Longitudinal section of a fruit approximately 3/8 inch in diameter. The great
increase in the torus is marked. The cortex contains fibro-vascular bundles, the pith
is free from them.

3. Cross section of fruit, showing the union of the styles to the tissue of the torus.

4. Longitudinal section of the fruit, showing the unused portion of the end of the
axis of the flower and the prolongation into the fruit of the pith tissue of the stem.

5. Longitudinal section of young fruit, showing one ovule cut in position. The
obturator is prominent.

PLATE 40

1. Longitudinal section of a young embryo in the micropylar end of the ovule.
The endosperm tissue is well developed.

2. Longitudinal section of an older embryo than shown in FIGURE I. The embryo
is elongated, straight, and shows a well-developed vascular system. The formation
of the seed coat is well advanced.

ROTA ae Pe Lien
, Pie : i4, )
4 : feos 5
; Metre

» * ~ at i ’ yy a
; WS te Hi all aptly
i ‘ : Mil Ky . MK “7 via ‘, Wate
) ee NA ;
: i Oar bit gle
4 i ; > ‘ re

; . ‘

UP
ys
; wee
s der amihte i Bits han isan Pads Ly pat aie ey Pete vad, Pes

Py |
)

; § \ ' 4 i VF sft ;

‘ : L }

is na “hk. re ai: wey iV eng! oe A ANE .
“ine of meer me Silla yl Ms teal bagNogan, poll tin Mine Br as el wale ie ee
yy fn) Oe d - /< or DP -.

aie ate é ni vd an wr ant iE te pa Malta & ny aril en an re o

oh Rate eed MAtyS A Wer tee Mee Se
tose ‘ { i 4 i al 2
. rity tee 4 le yap wo </ ial Oo fe st hy nie v Tn Ph » Usa ee in
onl Th : : ' $7 7k m 4 vy;
: ‘ - j wh fs ¥ r
F ; ; v. 4 % Veet]

3 ‘ 1 ‘ A ti ei vs j . ; ‘s 7 dein, ‘paee (& “eeipaih at I
a ’ e

i te} oe ' : , ‘ is gaat ed hh SES

vi ee ‘ } eR ey re

Fh ail aah Toi} , ieee A ay Sale ;

f " i * ane ‘tan a

ie ne ; 7 Lei A aa nahn des me an
Ai be Ne aD ea eo “Tae
‘ )
se 1: Hig Ee
Pte F Avy : vuve OL Deas ale mad hs itn vehi yi,
AE { i ony Aw ARGY way gerd mas
; "t av yt OF ee iid Wag wea

Ut Mee ib Seite i ee ic ag mia
wal) Gk vaity

» ©

i ) ; ; ve Way wiht WA 19 rived 4 La i, pay

oe wl Or eal ae Gs ee ah
, i , ' "pe they Ehud bie eo iy,
: oe ; ; 4 ( of igh Va by ert 4. ala “ssttal

, ty le Perey whe

sul * sp lapdelveg pian Ce lear ed 1 apeamine ae Ey
x ; hy eI ad GT Rake taal (0 ian as ;

' oe ciel tg aiid hava YaHalt Ar Se
° / aA wh I ry has PAu Ay fits.)
ein Lem se B

atl = ] ® is ae abi Felent ade rie bul

, ; Ps fi gad dae Seth al ribet at: “vt
P “iyi *. } i. ae tr in ms eG ety
ia Ae, P nie Salve val yelp org 4a

: ; ri FID tie A ot, hoe | !

ann:
v4

;
Pee
o

A CONTRIBUTION TO OUR KNOWLEDGE OF
SILVER SCURF (SPONDYLOCLADIUM ATRO-
VIRENS HARZ) OF THE WHITE POTATO

J. J. TAUBENHAUS

Texas Agricultural Experiment Station
(WITH PLATES 41-43)

The white potato is one of the staple foods in the United States.
With the increased cost of living, it is natural that more interest
should be directed to investigations of the diseases of that im-
portant crop. Silver scurf is a trouble which of late years has
attracted considerable attention from American plant patholo-
gists. Although much has been written, scientific data on the
nature of the disease as well as on the taxonomic relationship of the
causative organism are still wanting. The present paper is the
result of two years’ investigation carried on at the Laboratory of
Plant Pathology of the Delaware Agricultural Experiment Station.

HIsTORICAL.—Harz (2), in 1871, was the first to describe the
fungus Spondylocladium atrovirens, without, however, suspecting
it to be the cause of silver scurf. In 1897, Frank (5) described a
spot disease of the white potato, which he attributed to a new
fungus, Phellomyces sclerotiophorus Frank. The same disease,
which was fully described a year later (6), is now known to Ameri-
can pathologists as silver scurf. In 1903, Johnson (9) called
~ attention to Frank’s Phellomyces disease as being serious in Ireland,
and causing there a scab and dry rot of the tubers. That Johnson
was dealing with what we now know as silver scurf is certain.
However, it is difficult to account for his naming the disease a
““scab,’’ unless the material with which he dealt was scabby.

From 1897 to 1904, nothing new was added to our knowledge
of silver scurf. However in 1905-1907, Appel and Laubert (10)
and (11), in their work on silver scurf claimed that the sclerotia
of the fungus Phellomyces sclerotiophorus are merely the stromata of

1Of the staff of the Delaware Agricultural Experiment Station at the time of the
presentation of this paper.

on : 549

550 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN .

the fungus fruitings of Spondylocladium atrovirens. This view is
accepted by Clinton (12), Ejichinger (13), Massee (14, 16),
Bohutinsky (17), Erikson (19), Orton (21), Melhus (22), Bailey
(23), O’Gara (24, 25), and others. As we shall soon show, the
results presented in this paper are at variance with the views
presented above.

PRESENT WORK.—In this investigation ‘lie, writer wished to
determine definitely, (1) The true relationship of the sclerotia of
the fungus Phellomyces sclerotiophorus Frank with Spondylocladium
atrovirens Harz. (2) The pathogenicity of S. atrovirens as deter-
mined by pure culture inoculations. To settle I and 2, it was
necessary to grow the organism in pure culture. Of all the
writers here quoted, Johnson (9) is the only one who claims to
have grown it on artificial media, as he says, ‘Under artificial
culture (gelatin, agar and potato) I have found that the sclerotia
are readily produced, but up to the present time, neither in nature
nor by culture, has any typical fungal fructification been observed.”’
As will be shown later, Johnson was not dealing with S. atrovirens.
Appel and Laubert (10) do not report having grown the organism
on artificial media. They obtained the fructification of S. atro-
virens by placing affected tubers under moist conditions. They
decided this fungus to be the fruiting stage of Phellomyces sclerotio-
phorus. The conclusion for this relationship was drawn from the
fairly constant presence of the sclerotia of P. sclerotiophorus on
spots of potatoes affected with silver scurf.

In the fall of 1913, the writer collected a large quantity of
tubers which showed typical silver scurf (FIG. 1). The spots on
each tuber were carefully examined with a hand lens. These
tubers were all fresh and recently harvested. The sclerotia of
Phellomyces sclerotiophorus were present on 99 per cent of the
silver scurf spots. The remainder of the spots did not show any
sclerotia, and none of the spots in all the material showed any
fruitings of Spondylocladium atrovirens. A few of the infected
tubers were placed in moist chambers, while the remainder of the
material was used for cultural work. The method of isolation
was as follows: The tubers were first washed and cleaned in the
usual way. With a sharp knife, pieces of the spots were cut out,
one fourth of an inch deep. These pieces were then dropped in a
test tube, sterilized for one minute in a solution of 1-1,000 (alcohol

TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO aye!

50 per cent.) mercuric bichloride, then rinsed five times in sterile
water to wash off all traces of the disinfectant. Tubes with agar
medium were liquefied and cooled down to the proper temperature.
With a flamed and cooled scalpel, a piece of the potato material
was placed at the mouth of the tube and thoroughly crushed,
and then shaken up with the medium. The content of the tube
was poured into a petri dish and allowed to cool. The first series
of cultures consisted of some fifty plates; the spots cultured in this
case ail showed sclerotia of Phellomyces sclerotiophorus but not the
fruitings of Spondylocladium atrovirens. In four to five days, all
the plates showed a sclerotium-producing fungus, together with a
species of Fusarium. In some plates the latter predominated,
while in others the sclerotium-producing fungus predominated
(FIG. 3). These two organisms were transferred pure, to slants
on agar medium. More isolations were made to the extent of
crushing 800 different spots of silver scurf and culturing in the
same number of plates. Of the spots selected in this case, 80 per
cent showed sclerotia in varying number, while the remainder
were free from it, free in so far as that none could be seen with a
hand lens. In all the plates, with but one exception, the sclero-
tium-producing fungus, together with the species of Fusarium,
appeared after four days. From these results, it appeared that the
sclerotium-producing fungus, that is, Phellomyces sclerotiophorus
was the predominating stage in silver scurf, and that the fruitings
of Spondylocladium atrovirens appeared very rarely or under certain
cultural conditions, yet to be determined. None of the plates
were discarded at once. In many instances, either the Fusarium
colonies or Phellomyces were so numerous that they overran the
plate, thus giving no chance for slower growing organisms to
appear. Fifty per cent of such plates were discarded and the
remainder kept for further observation. After about two weeks,
other minute fungus colonies appeared in about one per cent
of the plates (FIGS. 4 and 5). In the one petri dish where no
growth had previously appeared, there now showed the same
minute fungus colonies practically pure. These plates were
watched and transfers made on slants of agar. In five to six
days the fungus under observation produced the typical fruitings
of Spondylocladium atrovirens. Pure cultures (FIG. 6) were now
easily obtained of this fungus, as well as of Phellomyces sclerotio-

552 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

phorus. It was at once evident and certain that they were distinct
fungi. Although the spore measurements varied considerably
when the fungus was grown on different media, yet, on the whole,
it agreed well with Spondylocladium atrovirens Harz. Careful
studies of the fungus Phellomyces sclerotiophorus revealed some
very interesting things. It was found that while the fungus
produced an abundance of sclerotia which are plainly visible to
the naked eye, yet under the microscope they are seen to be
provided with setae (FIG. 19). These setae were first thought to
be abortive conidiophores of Spondylocladium atrovirens. How-
ever, further studies showed hyaline one-celled spores, sparingly
formed, in typical acervuli but not on the sclerotia (FIGS. 20 and
21). This would place the fungus in the genus Colletotrichum.

It may be contended that the fungus Phellomyces sclerotiophorus
was not pure and that in our culture it was merely contaminated.
In order to settle this, dilution cultures of the spores were made.
In three to eight days, typical colonies of the Colletotrichum sclero-
tium-producing fungus appeared (FIGS. 7 and 9). In manner of
growth, these isolation colonies were identical with the sclerotium-
producing fungus obtained from the spots of silver scurf of the
white potato (FIGS. 8 and 10). Cultural work carried out in the
fall of 1914 and 1915 duplicated the results obtained the previous
year. This proved conclusively that Spondylocladium atrovirens
was in no way connected with Phellomyces sclerotiophorus, and
that the genus Phellomyces was not valid. Recently O’Gara (25)
described a new species of Colletotrichum which he isolated from
portions of underground stems of the white potato, and which
he named C. solanicolum O’Gara. Dr. O’Gara was kind enough
to send me a pure culture of his new Colletotrichum as well as
sectioned and stained slides of the fungus, as it appears natural
on the host and in pure culture. The writer observed at once
the resemblance of Dr. O’Gara’s Colletotrichum to the Colleto-
trichum-like fungus isolated from silver scurf spots. Cultures of
our strain were submitted to Dr. O'Gara, who pronounced it the
same or similar to his new Colletotrichum solanicolum. +

It will be remembered that Frank (5), in describing Phellomyces
sclerotiophorus did not carry out pure cultures of his new genus
and species. It should further be added that the sclerotia on the
living host often fail to produce setae, and that in pure culture

TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO 553

the former are either abortive, imperfectly developed, or not very
abundant. It will be readily seen, therefore, why Frank was led
to create the new genus Phellomyces, and overlooked its resem-
blance or relationship to the genus Colletotrichum. Moreover,
Frank’s Phellomyces is not a sterile fungus, since it produces
Colletotrichum-like spores. Hence, the genus Phellomyces is not
valid.

Recently the writer (20) described the charcoal rot of sweet
potatoes, which is attributed to the fungus Sclerotium bataticola
Taub. This organism greatly resembles Phellomyces. However,
it produces neither setae nor spores but sclerotia only. Hence
the writer placed this fungus in the genus Sclerotium. It matters
little whether sclerotia are minute or large, free or buried in the
tissue; as long as they are sterile bodies, they should be placed
in the genus Sclerotium. In such cases, the less genera we have,
the better. It is evident then, that the Phellomyces of Frank,
which is found associated with silver scurf, is a Colletotrichum.
It is probably also the same fungus as Vermicularia atramentaria
Berk. & Br. (1). Halsted, (3) in 1894, while working on a stem
blight of the white potato, met with this fungus; he says: ‘The
fungus in question seems to be Vermicularia atramentaria Berk.
& Br., but the amount it has to do with causing the destruction
of the crop is an open question.’’ The species V. atramentaria
is recognized by Saccardo (8), Rabenhorst (7), and Clements (15).
However, the species is poorly described and no measurements of
spores are given. Studies were made by the writer, of the various
specimens of Vermicularia atramentaria found at the herbarium
of the New York Botanical Garden. From these studies, it
seemed evident that Vermicularia atramentaria is not a Vermicu-
laria. The bodies which may be taken for pycnidia of Vermicu-
laria seem to be sterile sclerotia; these may be with or without
black setae (FIGS. I9-21). The spores of V. atramentaria as
stated above, are not borne in the sclerotia, but in typical acervuli
with setae near the sclerotia (FIGS. 21 and 20). Of the collections
of Vermicularia atramentaria at the New York Botanical Garden,
one specimen is of particular interest. It reads as follows:

““C, Roumegére.—Fungi Gallici exsciccati.
‘2968. Vermicularia atramentaria Bk. et Br. Fung.
“‘n. 430, forma sclerotioides.”’

554. MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

‘‘Aprés l’expulsion des spores et la chute des soies, le périthéce.
(rappelant par sa consistance et son aspect le Sclerotium durum)
persiste sur les tiges desséchées du Solanum tuberosum.”
‘“Plomereuc (Seine-Inférieure, Mars 1884).”’
‘‘ ABBE LETENDRE.”’

From our own studies and as already stated, what is taken
for pycnidia are only sterile sclerotia, since studies made of these
pycnidia at different stages of development in pure culture and
on the host proved them to be sterile bodies. The fungus therefore
is perhaps an intermediate form between Vermicularia and Col-
letotrichum, although it fits in better in the latter. There are no
described species of Colletotrichum which are known to produce
sclerotia. However, there seems no doubt but that many of the
species of Vermicularia, upon culturing, would show characteristics
of the former genus.

It seems evident that Phellomyces sclerotiophorus Frank is the
same as Vermicularia atramentaria Berk. & Br. and also the same
as Colletotrichum solanicolum O’Gara. However, in following
the rule of priority, the fungus becomes Colletotrichum atra-
mentarium (Berk. & Br.) Taubenhaus. Syn. Vermicularia atra-
mentaria Berk. & Br., 1850; Phellomyces sclerotiophorus Frank,
1897; Colletotrichum solanicolum O’Gara, 1915. The fungus needs
no further description, as it has been fully described by O’Gara.
However, it should be added that the spore measurements as
given by him (3.5-5.u X 17 w) are found to be much more variable
in length (FIGs. 24 and 25).

The fungus Colletotrichum atramentarium does in no way re-
semble Periola tomentosa Fr. occurring on dead potato vines in
Europe. Further studies of this genus will show that it is probably
invalid.

PATHOGENICITY.—It has already. been pointed out that in
culturing silver scurf spots, the great majority of the plates
yielded the fungus Colletotrichum atramentarium (FIG. 3). One
would therefore be tempted to suppose that the latter fungus was
the cause of silver scurf. Moreover, no previous workers reported
infection with spores of pure cultures of Spondylocladium atro-
virens. Appel and Laubert (11) in their infection experiments
merely used spores of this organism obtained from infected tubers
which were kept in a moist chamber. These spores were diluted

TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO 555

in water and the liquid used for inoculation. In order to determine
definitely the pathogenicity of Spondylocladium atrovirens, spores
from a pure culture of the latter were suspended in sterile water
and sprayed on healthy white potatoes. Before inoculation
these tubers were washed and disinfected for ten minutes in a
solution of 5 parts of formaldehyde in 95 of water. They were
then kept two weeks in sterile moist chambers to see if any disease
would appear. In making microscopic mounts twenty-four hours
after infection, the spores of Spondylocladium atrovirens were seen
to germinate (FIGS. 27, 28, and 29) and to break through the
epidermis (FIG. 26). This agrees with the observations of Appel
and Laubert (11). In about two to four weeks, typical spots of
silver scurf appeared. This was repeated several times with the
same results. The symptoms of the artificial infection were
identical with those seen in nature, with the exception, however,
that the sclerotia of Colletotrichum atramentarium were absent.

A series of inoculations was also carried out with spores from
fresh cultures of Colletotrichum atramentarium. At no time did
infection appear. Inoculations were also made by inserting bits
of mycelium and sclerotia of the above fungus into slits made in
the epidermis of the tuber. In no case did infection appear.
This clearly shows that Spondylocladium atrovirens Harz and not
Colletotrichum atramentarium (Berk. & Br.) Taub. is the cause of
silver scurf. Nevertheless, and as previously pointed out, Frank
(6) and Johnson (9) recognize a form of dry rot due to Colleto-
trichum atramentarium. The writer agrees with Appel and
Laubert (11) that the dry rot of Frank and of Johnson above men-
tioned was probably caused by another organism, perhaps
Fusarium. It has already been pointed out that Halsted (3) did
not consider Colletotrichum atramentarium, to be the cause of the
stem wilt of white potatoes which he studied. Stewart (4) in
working with an apparently similar stem blight of potatoes
attributes the probable cause to Oospora rosea (Preuss.) Sacc. &
Vogel, or to Melanospora ornata Zukal. Stewart could not find
the association of Colletotrichum atramentarium with his stem
blight, as previously noted by Halsted. It is very probable that
both Halsted and Stewart were then dealing with a stem blight
caused by some species of Fusarium. Dr. Manns! (18) in his work

1Dr. Manns has pronounced his Vermicularia identical with Colletotrichum atra-
mentarium (Berk. & Br.) Taub.

556 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN |

on dry rot of the white potato has also met with the fungus
Colletotrichum atramentarium, as he says: ‘‘It is common to find
associated with the Fusarium and likewise penetrating the tuber,
sometimes to a depth of one-fourth to one-half inch, a fungus
of the genus Vermicularia. ... The Vermicularia was present
to an extent of 10.3 per cent, .... When used alone it brings
about no disease symptoms. If it assists any in bringing about
the disease, its work is that of a semi-parasite which follows the
openings made by Fusarium.’ It is very probable that Frank
(6) and Johnson (9) originally dealt with the dry rot caused by
several Fusaria, which were obscured and overrun by Col-
letotrichum atramentartum. The probability of the latter fungus
being a saprophyte is also admitted by O’Gara,! who writes:
“T do not think that the Colletotrichum is a very active parasite.”
It is safe to assume that Colletotrichum atramentariumis a common
saprophytic soil organism. The writer has found it time and
again on dead and dying stems of white potato, especially if the
hills were fully mature. It is noteworthy to add that on dead
stems the sclerotia are larger than they are when found following
the silver scurf fungus (Spondylocladium atrovirens) or on partly
dying potato vines. However, when these larger sclerotia are
dropped on an agar medium, the resulting growth is identical with
Colletotrichum atramentarium. This would seem to indicate that
the organism is only at best a semi-parasite under certain climatic
conditions, since there must be some element in the living host
which is unfavorable to the fungus. It is also interesting to add
that the setae of the acervuli are much more abundant in pure
culture on an agar medium and on steamed potato vines than
they are found in nature. When found accompanying the silver
scurf fungus, the setae are almost wanting. Species of Colleto-
trichum, as a rule, are not known to produce sclerotia, nor to
reproduce by means of such bodies. Colletotrichum atramentarium,
however, is an exception, since, in the former, the sclerotia seem
even to be a more important phase of reproduction than are the
spores; the latter are formed only in young cultures and very
sparingly on the host. As the organism increases in age, spore
formation in pure culture is dispensed with, and an abundance of
sclerotia with or without setae are formed in layers of concentric

‘ Correspondence dated August 17, 1915.

TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO Saye

zones (FIGS. 9 and 10). The organism too, is a vigorous grower,
compared to Spondylocladium atrovirens, the latter of which forms
small colonies which are seldom larger then one third of an inch
in diameter (FIG. 6). Colletotrichum atramentarium will grow
and increase in zonation as far as space permits in the petri dish
(FIGS. 9 and 10).

How SILVER SCURF IS CARRIED OVER.—Silver scurf is carried
with the seed and with the soil. To prove this, a number of
tubers which were infected with silver scurf were planted in a clean
soil in the greenhouse. In another lot, a pure culture of the
fungus Spondylocladium atrovirens Harz was mixed with clean
soil, and healthy disinfected tubers planted therein. Healthy and
disinfected tubers were also planted in clean soil to serve as
checks. The plants in all the lots grew well, and in four months
mature hills of potatoes were formed in each lot. The results
showed that the lot infected with a pure culture of S. atrovirens
produced 100 per cent diseased tubers. Where infected seeds
were used, the new tubers showed 60 per cent infection. All
the checks were free from the disease. A second crop of potatoes
was grown on the same plots. In this case, however, only
healthy disinfected seeds were planted. At the end of the experi-
ment, the tubers in the check plot were all healthy, while those in
the other two plots were infected with silver scurf. This clearly
shows that the seed as well as the soil, is a carrier of the disease.
There is no doubt but that the fungus Colletotrichum atramen-
tarium, like Spondylocladium atrovirens, is also carried by the above
two agencies. In the plot where only infected tubers were planted,
Colletotrichum atramentarium was also present on the spots of the
new crop as well as on the dying vines.

PATHOLOGICAL MORPHOLOGY.—Silver scurf is only an epidermis
disease (FIG. I1). At no time has the writer been able to find
evidence that the fungus Spondylocladium atrovirens Harz is
capable of producing a scab, or a dry rot. Wherever such cases
came to our attention, the material was immediately cultured,
and the resultant flora was rich in Actinomyces, Fusaria, and other
Hyphomycetes, but not with Spondylocladium atrovirens. The
same is also true for Colletotrichum atramentarium (FIGS. I2, 19,
20, and 21), with the exception however, that the latter is capable
of entering deep into tubers which have previously rotted by other
organisms, such as Fusaria.

558 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

SUMMARY

1. It has been proved that Spondylocladium atrovirens Harz is
the cause of the disease known as silver scurf.

2. The fungus Phellomyces sclerotiophorus Frank is not in any
way connected with Spondylocladium atrovirens Harz.

3. The fungus Phellomyces sclerotiophorus Frank, although very
prevalent on the silver scurf spots, is merely a secondary invader.

4. It has been shown that the genus Phellomyces is not valid,
since the genus belongs to Colletotrichum.

5. Phellomyces sclerotiophorus Frank is the same as Vermicularia
atramentaria Berk. & Br. and the same as Colletotrichum solant-
colum O’Gara.

6. Following the rules of priority Colletotrichum solanicolum
O’Gara becomes Colletotrichum atramentarium (Berk. & Br.) Taub.

7. Colletotrichum atramentarium is apparently a saprophyte or
at best, a very weak parasite.

8. Silver scurf is carried with the seed and soil.

g. Silver scurf is only a skin disease.

BIBLIOGRAPHY

1. Berkeley, M. J., & Broome, C. E. Notices of British fungi. Ann.
and Mag. Nat. Hist. IT.5::378-379. 2650.

2. Harz, C. O. Einige neue Hyphomyceten Berlin’s und Wien’s nebst
Beitragen zur Systematik derselben. Bull. Soc. Imp. Nat.
Moscow 44: 129-130. 1871.

3. Halsted, B. D. Seventh annual report 352-354. 1894.

4. Stewart, F. C. Potato diseases on Long Island in the season of
1895. N. Y. (Geneva) Agr. Exp. Sta. Bull. 101: 83-84. 1895.

5. Frank, A. B. Die Fleckenkrankheiten der Kartoffelschale mit dem
Phellomyces sclerotiophorus Frank. Kampfbuch gegen die Schad-
linge unserer Feldfriichte 182-185. 1897. (Berlin.)

6. Frank, B. Die Phellomyces Faule. Ber. Deutsch. Bot. Ges. 16:
280-281. 18098.

7. Allescher, A., in Rabenhorst, L., Krypt. Fl. 1°: 512. 1901.

8. Saccardo, P. A. Syll. Fung. 4: 681.

9. Johnson, T. Phellomyces sclerotiophorus, a cause of potato scab
and dry rot. Econ. Proc. Roy. Soc. Dublin 1: 161-165. 1903.

10. Appel, Otto, & Laubert, R. Die Konidienform des Kartoffelpilzes,
Phellomyces sclerotiophorus Frank. Ber. Deutsch. Bot. Ges. 23:
218-220. 1905.

TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO 559

11. Appel, Otto, & Laubert,R. Die Konidienform und die pathologische
Bedeutung des Kartoffelpilzes Phellomyces sclerotiophorus Frank.
Arbeit. Kaiserl. Biol. Anst. fiir Land- und Forstw. 5: 435-441.
1907.

12. Clinton, G. P. Scurf, Spondylocladium atrovirens Harz. Conn.
Agr. Exp. Sta. Ann. Rep. 31-32: 357-359. 1908.

13. Eichinger, A. Zur Kenntnis einiger Schalenpilze der Kartoffel.
Ann. Myc. 7: 356-364. 1909.

14. Massee, George. Dry scab of potatoes. Spondylocladium atro-
virens Harz. Roy. Bot. Gard. Kew. Bull. 1: 16-18. 1909.

15. Clements, F.E. The genera of fungi, 160. 1909.

16. Massee, George. Diseases of cultivated plants and trees, 478-480.
1910 (London).

17. Bohutinsky, G. Beitrage zur Erforschung der Blattrollkrankheit.
Zeits. Landw. Versuchsw. in Oesterreich 13: 607-633. I9I0.

18. Manns, Thos. F. The Fusarium blight and dry rot of the potato.
Ohio Agr. Exp. Sta. Bull. 229: 315-316. I9II.

19. Erikson, Jakob. Fungoid diseases of agricultural plants [Tr. from
the Swedish by Anna Molander], 112. 1912 (London).

20. Taubenhaus, J. J. The black rots of the sweet potato. Phyto-
pathology 3: 159-165. 1913.

21. Orton, W. A. Potato tuber diseases. Farmers’ Bull. 544: 3-16.
LOLS.

22. Melhus, I. E. Silver scurf, a disease of the potato. U.S. Dept.
Nee Bur Ple-lnd. Cire 127. 15.24. “1013

23. Bailey, F. D. Notes on potato diseases. Phytopathology 4: 321-
2o2.- 1014:

24. O’Gara, P. J. Occurrence of silver scurf of potatoes in the Salt
Lake Valley, Utah. Science Il. 41: 131-132. 1915.

25. O’Gara, P. J. New species of Colletotrichum and Phoma. Myco-
logia 7: 38-41. I9I15.

Explanation of plates 41-43

Fic. 1. Spots of silver scurf (Spondylocladium atrovirens Harz) of the white potato.

Fic. 2. Tuber infected with silver scurf, showing shrinkage due to the disease.

Fic. 3. Crush culture of a silver scurf spot of white potato. The resultant is a
pure growth of Colletotrichum atramentarium (Berk. & Br.) Taub. and not Spondylo-
cladium atrovirens Harz, the cause of the disease. S. atrovirens is a slow grower and
hence easily overrun by more vigorous saprophytes.

Fics. 4 and 5. Two of the few plates which yielded a culture of Spondylocladium
atrovirens from cultured spots of silver scurf. Notice the small colonies of S. atrovirens
intermingled and overrun with Fusaria and Colletotrichum atramentarium.

Fic. 6. Pure culture of Spondylocladium atrovirens Harz.

560 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Fic. 7. Pure culture, three days old, of Colletotrichum atramentarium isolated
from silver scurf spots of white potato,

Fic. 8. Pure culture three days old of Colletotrichum atramentarium obtained from
Dr. O'Gara.

Fics. 9 and 10. Colletotrichum atramentarium transfers from Fics. 7 and 8, showing
zonations of sclerotia and the abundance of the latter in pure culture.

Fic. 11. Cross-section of a spot of silver scurf of white potato to show relationship
of the fungus Spondylocladium atrovirens Harz to the host tissue. Notice the fungus
is confined to the epidermis of the tuber.

Fic. 12. Cross-section of a silver scurf spot of a white potato tuber showing sclerotia
of Colletotrichum atramentarium (Berk. & Br.) Taub.

Fic. 13. Conidiophores and conidia of Colletotrichum atramentarium.

Fics. 14-16. Germinating spores ot Colletotrichum atramentarium.

Fics. 17 and 18. Germinating spores of Colletocrichum atramentarium, showing forma-
tion of appresoria at tip of germ tube.

Fic. 19. Single sclerotium with setae of Colletotrichum atramentarium, showing its
relationship to the epidermis of a killed white potato vine.

Fics. 20 and 21. Sclerotia and ascervuli of Colletotrichum atramentarium on dead
potato vines.

Fic. 22. Surface black mycelium of Colletotrichum atramentarium in pure culture.

Fic. 23. Hyaline deep-growing mycelium of Colletotrichum atramentarium in pure

culture.
Fics. 24 and 25. Showing variations in sizes of spores of Colletotrichum atramen-

tarium in pure culture.
Fic. 26. Germinating spore of Spondylocladium atrovirens breaking through the

epidermis of the host.
Fics. 27-29. Germinating spores of Spondylocladium atrovirens Harz.

VOLUME VI, PLATE 41

N. Y. Bot. GARDEN

Mem.

SILVER SCURF OF THE WHITE POTATO

BENHAUS:

TAU

iJ, PLATE 42

VOLUME

GARDEN

Ve bOm

MEM.

5 WHITE POTATO

THE

SCURF OF

SILVE

TAUBENHAUS:

Mem. N. Y. Bot. GARDEN VOLUME VI, PLATE 43

|
|

TAUBENHAUS: SILVER SCURF OF THE WHITE POTATO

THE EMBRYO-SAC AND POLLEN GRAIN AS
COLLOIDAL SYSTEMS

Francis E. LLtoyp
McGill University

One of the most insistent problems of the present time in the
field of biology is the relation of growth to the behavior of colloids,
especially those known as emulsion-colloids.1_ These bodies show
the phenomena of swelling at low concentrations of acids and
alkalis, and of shrinkage in salts. Certain of them (albumin,
etc.) coagulate irreversibly at high temperatures, with concen-
trations of acids in wide amplitudes, possibly (as indicated by
my own experiments) at certain concentrations of alkalis, by
mechanical disturbance (shaking, pressure); and to this group of
bodies protoplasm belongs. It seems now clear that protoplasm
is a hydrophile emulsion colloid, the hydratation capacities of
which are functions of the solutes in the watery medium which
bathe it. Any change in the concentrations of the solutions must
cause corresponding changes in the amount of water within the
protoplasm, and this must change the spacial relations of the
water-poor dispersoids and water-rich disperse medium, evidenced
in swelling or shrinkage. Changes in surface tensions, electrical
charge, etc., may be mentioned as indicating the vast possibilities
which can result. One possible and important result is the
change in permeability which can be readily conceived as being
a function of the changes in spacial relations above mentioned.
When the antagonistic effects of mixed solutes, the coagulating
effects of various reagents, and the possible dissolution of sub-
stances (such as lipoid), either proper to or associated with proto-
plasm by appropriate solvents, are added as further possibilities
of affecting the internal relations, it becomes at once evident that
the problems in this field are both complex and difficult.

For the present purpose, one such difficulty which confronts the
experimental cytologist is the presence of water vacuoles in the
majority of growing plant cells. It has indeed been assumed, by

1 Such as jelly of any kind, protein bodies in unpeptized condition, such as protoplasm.
38 561

562 . MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Borowikow,! that the agents which cause swelling in emulsion
colloids would increase growth, and, for the moment, it is not
possible to discount his results, which he holds substantiate his
assumption. He concerned himself with the period of elongation
(Streckungsphase), that period, namely, when the growing cells
take on a maximum water volume by adding to the number and
size of vacuoles. And it is this fact which forces the criticism that
we have no knowledge at the present moment of how swelling,
shrinking, and coagulating reagents affect the relation of changes
of hydratation to the capacity of protoplasm to secrete and to
hold water within the vacuoles. And when it is pointed out that
the water in the vacuoles is not by any means a simple solution of :
electrolytes, but contains albumin (Loew) and mucilages, and
frequently also suspension colloid bodies (tannins, etc.), substances
which must act in antagonism to the protoplasm in so far as they
will compete with it in the hydratation processes, as also must
investing membranes (cellulose and pektose walls, derived muci-
lages, such as that of mallows and cacti), we see the need of investi-
gation which is directed toward forming some conception of how
these interactions proceed.

The embryo-sac and pollen grain exemplify the above. The
former is a group of cells invested by very delicate cellulose
membranes, and in which the development of vacuoles reaches a
maximum. ‘The resulting mechanism of endosperm-cell and egg-
apparatus (in 7orenia) is so delicately equilibrated that the whole
is thrown out of order by the plasmolytic effects of a solution of
the concentration of slightly over 0.1N potassium nitrate. It is
difficult to conceive the effects of reagents to be identical when
operating upon such a system as in the case of the protoplasts of
the pollen grain,’ from which all water vacuoles (some pollens, such
as that of Calla, do not conform to this description) are absent.
In this case, the emulsion colloid complex which we call proto-
plasm shows at once the changes in hydratation due to reagents.
Preliminary studies have shown that the protoplasts can swell
after previous shrinkage in concentrated glycerine, salts, sugars,
and indeed burst* at surprisingly high concentrations of these

! Ueber die Ursachen des Wachstums der Pflanzen. 1. Bot. Inst. Univ. Odessa.

2 Pollen grains of Eschscholtzia, Lupinus, and many others are examples.

* Pollen of cotton bursts in 50 per cent. glycerine, 25 per cent. cane sugar, 0.45N
KNO;. That of Eschscholtzia frequently bursts in the course of twenty-four hours in
very strong glycerine.

LLOYD: COLLOIDAL SYSTEMS 563

and other reagents (acids and alkalis). This and other behaviors!
preclude a contributing role of water vacuoles, while they indicate
strongly the value of the suggestion that the hydratation effects
alter the permeabilities of the protoplasm, which themselves can
be momentarily altered. Thus, the amount of water already in
the protoplasm affects the hydratating power of a given reagent,
as shown by pollen with different initial quanta of water (im-
bibed). It is hoped that this brief report will serve to indicate
the importance of directing research toward the behavior of
the congeries of colloids constituting protoplasm as such, as dis-
tinguished from systems in which complications arise from such
disturbing factors as water-vacuoles, mucilages, etc., without
however underrating the importance of understanding the inter-
relations of these and the protoplasm.

1 Swellings and coagulation effects caused by acids and alkalis and the characteristic
forms so produced; change in size of dispersoids, as in the case of oil.

ny
i
9
‘

;

*
“

J
‘es
5
yal
4 Pt

Laan
ns
; <
7
F f athe Cae
GA
Cae eG
: he 1?
mye I Wy
\ . Daa 4 ee @
j Dee y
ee ing {
jn
‘si A Ang é%
i] “
fa Lee oe |
to's
',
; ae ‘i
iad Tay |
i
jas ee 5!
s
*
af

THE VEGETATION OF ANEGADA

N. L. Britton
New York Botanical Garden

I visited the little-known island Anegada! in February, 1913, in
company with Mr. W. C. Fishlock, then Agricultural Instructor
for the Virgin Islands, and in charge of the Botanical Station at
Roadtown, Tortola. The trip was made during our botanical
exploration of the Virgin Islands, which included the examination
of St. Thomas, St. Jan, Tortola, Virgin Gorda, and Anegada, and
landings upon a number of the smaller islands of the archipelago.’
Anegada is the most northern and eastern island of the group, and
lies north of the edstward prolongation of the axis of the archi-
pelago. Itis separated from Virgin Gorda, which lies nearly south
of it, by about 13 miles; the greatest depth of water between the
two is about 11 fathoms. Anegada is about 10 miles long and a_
little more than 2 miles wide at its broadest part, which is near the
middle of the island; its highest point, which is given at 30 feet
on the sailing chart, is a little east of the center. Deep water
occurs within a few miles to the north and west, 1,100 fathoms
being reached about 12 miles to the southwest. The eastern
and central portions of the island are a nearly level limestone
plain, slightly eroded, but the western part is a sand plain, with
large saline areas and many salt ponds. There are small areas of
arable land; originating, in part, from the decay of the limestone,
more or less mixed with calcareous sand. The population at the
time of our visit consisted of several hundred negroes.

While situated on the same bank as the other Virgin islands,
Anegada is totally different from any of them, in being wholly
composed of limestone and sand and rising only a little above the
water, the other larger Virgin islands being hills which rise to
elevations of 500 to 600 meters and are mostly composed of
eruptive rocks, although some stratified series were locally ob-

1 Also written Anagada.

2 Jour. N. Y. Bot. Gard. 14: 99-102. 1914.
565

566 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

served, but there is scarcely any limestone recorded. The origin
of Anegada is therefore wholly different from the rest of the group
and its limestone very much resembles that of the Bahamas,
Bermuda, and other aeolian islands. Its soil is therefore quite
different from that of the other Virgin islands, and some of its
plants are not known to grow on them.

The only detailed published account of Anegada known to me
is that of Robert Hermann Schomburgk, printed on pages 152-170,
with a map, in the second volume of the Journal of the Royal
Geographical Society of London, published in 1832. In these
years, and previously, the island was noteworthy for the number
of wrecks of sailing vessels which occurred there, and wrecking
was the principal occupation of the inhabitants and was evidently
quite lucrative. Schomburgk surveyed the island in 1831; his
paper ,contains descriptions of its geography, oceanography,
geology, and climate, with notes upon its plants and animals, and
a list of 53 vessels wrecked on its reefs within the memory of its
inhabitants up to that time. He does not appear to have made
any collections, although, as a member of the Horticultural
Society of Berlin, he might have been expected to have brought
out some botanical specimens; Professor Urban remarks, “‘ Plants
do not appear to have been collected on this island.’ Schom-
burgk records the discovery of a definite northwesterly current
about the island and accredited certain deposits which he observed
on its southern side to drift-matter in this current, originating as
part of the sediment brought down by the Orinoco River. He
remarks, ‘‘This explains the reason why there are many plants to
be met with on the island which do not exist in any of the other
Virgin islands, but are peculiar to South America.” He states the
greatest width of the island as 4.25 miles, but his map shows this
to be excessive, and he gives the greatest height as 60 feet above
the sea, at a point just east of the settlement, but we saw no
such altitude.

The plants mentioned by Schomburgk are:

Arundo, on sand hillocks, northwestern side. We saw no
large grass on the island, but we did not explore the whole
of the northwestern coast.

1Symb. Ant. 1: 152. 1808.

BRITTON: THE VEGETATION OF ANEGADA 567

Suriana maritima. This we found abundant in sandy parts
of the west end.

Bignonia Leucoxylon, on islands in the Flamingo Pond. This
is evidently Tabebuia heterophylla, which we saw at several
points.

Species of Malpighia, Mimosa, Eugenia, Croton, Agave, and
Epidendrum are mentioned as plants not observed by him
on the other Virgin islands. His Mimosa may be the tree
here described as a new Acacia; we found species of the
other four genera.

Malpighia angustifolia, which he records as in great abun-
dance about the settlement, is evidently M. linearts.

Malpighia urens, west of the settlement.

Malpighia (perhaps coccifera), growing with M. urens.

Laurus Culilaban.—We saw no Lauraceae.

Coccoloba Uvifera, in great quantities at the west end, where
we also found it abundant.

Rhizophora Mangle, which is abundant.

Scaevola Lobelia, which is what we call Scaevola Plumiert
and is plentiful on coastal sands.

Robinia squamata “with showy yellow flowers,’
Pictetia aculeata.

Agave vivipara, probably Furcraea.

A Croton, ‘‘which, amongst the Virgin Islands, is peculiar
to Anegada, seems to extend over the whole island.” We
saw only Croton discolor.

A red Ulva, on margins of ponds.

During our visit of two days, specimens of 123 species of land
plants were obtained; the collection is probably insufficient to base
any general conclusions upon, because, presumably, there are more
species growing there; we took a specimen of every species we saw,
examined at least a square mile of the sandy plain toward the
west end and an equal area of the rocky plain toward the east
end, and the surface conditions are very uniform, but we did not
have time to traverse the whole island. I hope that a collector
may be located there for a considerable period of time and the
entire flora ascertained.

It is probable that some of the species of trees and shrubs ori-
ginally growing on Anegada have been exterminated. Schom-

’

is evidently

568 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

burgk, in 1832, refers to ‘‘the sale of the underwood, which was
progressively cleared away, and which, being full of gum, had a
preference in the market of St. Thomas.”’

There are apparently four endemic species in our collection,
these being an Acacia, forming a small tree, here described; a
Chamaesyce, pronounced by Dr. Millspaugh to be undescribed
(C. anegadensis Millsp. Field Mus. Bot. 2: 394. 1914); an Aste-
phanus, regarded as new by Dr. Schlechter, and to be described
by him, and a new Arthonia, here described by Professor Riddle.
All the other species of our collection are found in one part or
another of the West Indies, none being characteristic of South
America, though many reach South America in their southward
distribution. That a number of the Anegada species do not
occur in the other Virgin islands was to have been expected, be-
cause there is no similar limestone area anywhere else in the
archipelago.

No evidence former land connection of Anegada in any
direction has been adduced; all the species observed by us may
well have been brought there by oceanic or transoceanic distri-
bution.

LIsT OF SPECIES
PANICUM GEMINATUM Forsk.

In a water hole near the settlement. St. Thomas:—Florida;
Bahamas; West Indies south to Martinique and Aruba; conti-
nental tropical America; tropical Asia and Africa.

SPOROBOLUS ARGUTUS (Nees) Kunth.

Border of marsh. St. Croix:—southern United States; Ba-
hamas; Jamaica; Cuba to Porto Rico; Bonaire; Curacao; Mexico.
SPOROBOLUS VIRGINICUS (L.) Kunth.

Border of marsh, Virgin Gorda; St. Jan; Tortola; Vieques :—
southeastern United States; Bermuda; Bahamas; West Indies;
continental tropical America; tropical Africa and Australasia.
DACTYLOCTENIUM AEGYPTIUM (L.) Willd.

Waste grounds. Tortola; St. Jan; St. Thomas; Vieques; St.
Croix:—southern United States; Bahamas; West Indies; conti-
nental tropical America and Old World tropics.

ERAGROSTIS CILIARIS (L.) Link.

Frequent on the rocky plain. Virgin Gorda; Tortola; St. Jan;

St. Thomas; Culebrita; Vieques; St. Croix:—southern United

BRITTON: THE VEGETATION OF ANEGADA 569

States; Bermuda; Bahamas; West Indies; tropical continental
America; Old World tropics.
PASPALUM HELLERI Nash.

Sandy plain, West End, and occasional on the rocky plain.
Culebra; Vieques; St. Thomas; St. Jan; Tortola:—Florida;
Bahamas; West Indies south to Barbadoes.

ERAGROSTIS URBANIANA Hitchc.

Sandy plain, West End. Bahamas; Porto Rico; Bonaire;
Curacao; Aruba.
CYPERUS CUSPIDATUS H.B.K.

Occasional on the rocky plain. Florida; Bahamas; Cuba;
continental tropical America.

CYPERUS BRUNNEUS Sw.

Sandy plain, West End. Virgin Gorda; St. Thomas:—Florida;
Bermuda; West Indies south to St. Vincent; Central America;
Fernando de Noronha.

CYPERUS ELEGANS L.
In a water hole near the settlement. St. Thomas; St. Jan:—
Florida; West Indies and tropical continental America.

CYPERUS FULIGINEUS Chapm.
Occasional on the sandy plain, West End. Florida; Bahamas;
Cuba; Bonaire; Curacao.

FIMBRISTYLIS INAGUENSIS Britton.
Frequent on the sandy plain, West End. Cuban Cays; Baha-
mas.

THRINAX Morrisit Wendl.

Occasional on the sandy plain, West End. Anguilla. Only
small barren trees were observed at the time of our visit but Mr.
Fishlock subsequently: obtained young fruiting inflorescence.
SABAL.

A few trees on the sandy plain, West End. None of them were
in flower or in fruit at the time of our visit, and I am therefore
unable to determine the species.

TILLANDSIA UTRICULATA L.

On a tree near the settlement. Tortola; Culebra; Vieques :—
Bahamas; Jamaica; Cuba to ‘Trinidad; continental tropical
America.

570 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

COMMELINA ELEGANS H.B.K.

Frequent on the rocky plain. St. Thomas:—Florida; Bermuda;
West Indies and continental tropical America.
FURCRAEA TUBEROSA Ait. f.

On the rocky plain near the settlement. Probably introduced.
Porto Rico; Vieques; Culebra; St. Croix:—St. Kitts.

AGAVE MISSIONUM Trelease.
Frequent on the rocky plain. Virgin Gorda; St. Jan; St.
Thomas; Culebra.

IBIDIUM LUCAYANUM Britton.
Occasional under bushes on the rocky plain. Florida; Bahamas;
Porto Rico.

EPIDENDRUM PAPILIONACEUM Vahl.

Frequent on low trees and shrubs. Virgin Gorda; Tortola; St.
Thomas; Culebra; Vieques:—Hispaniola; Mona; Porto Rico;
St. Barts. Recorded from the Bahamas and St. Croix.
TETRAMICRA ELEGANS (Hamilt.) Cogn.

Frequent on the sandy plain, West End. St. Jan; St. Thomas;
St. Croix:—Porto Rico; Antigua; Guadeloupe.

BATIS MARITIMA L.

Common in salinas, West End. St. Thomas; Culebra; Vieques;
St. Croix:—southeastern United States; southern California;
Bahamas; Jamaica; Cuba; Hispaniola; Porto Rico; Anguilla;
Martinique; Margarita; Bonaire; Curacao; continental tropical
America; Sandwich Islands.

PILEA TENERRIMA Miquel.

Occasional on the rocky plain. Florida; Bahamas; Cuba;
Jamaica.

PILEA TRIANTHEMOIDES (Sw.) Lindl.

Occasional on the rocky plain. West Indies.
DENDROPEMON CARIBAEUS Krug & Urban.

On a tree near the settlement. St. Jan; St. Thomas; St. Croix:—
Porto Rico; Antigua to St. Vincent.

SCHOEPFIA OBOVATA C, Wright.

Occasional on the sandy plain, West End. Bahamas; Cuba;
Porto Rico.

BRITTON: THE VEGETATION OF ANEGADA 571

CoccoLoBis UVIFERA (L.) Jacq.

Frequent on the sandy plain, West End; also in coastal thickets.
Virgin Gorda; St. Thomas; St. Jan:—Florida; Bermuda; West
Indies and tropical continental America.

CoccoLopis KruaGir Lindau.

Occasional, both on the sandy plain, West End, and on the
rocky plain. Bahamas; Jamaica; Porto Rico; St. Martin; Bar-
buda.

SALICORNIA PERENNIS L. (Salicornia ambigua Michx.)

Saline soil, West End. West Indies; eastern United States.
ACHYRANTHES PORTORICENSIS (Kuntze) Standley. (Alternanthera

portoricensts Kuntze.)

Under small trees and shrubs on the rocky plain. Culebra:—
Porto Rico; Little St. James Island, St. Jan.

LITHOPHILA MUSCOIDES Sw.

Occasional on the rocky plain. St. Martin:—Bahamas; Cuba
to Martinique; Bonaire; Curacao; Aruba.
PHILOXERUS VERMICULARIS (L.) R. Br.

Common in salinas, West End. St. Thomas; Virgin Gorda:—
Florida; Bahamas; Jamaica; Cuba to Trinidad; Cayman Islands;
Curacao; northern South America.

PISONIA SUBCORDATA Sw.

Occasional on the sandy plain, West End. Tortola; St. Thomas;
Culebra; Vieques:—Porto Rico to Martinique.

CyPSELEA HUMIFUSA Turpin.

Occasional on the rocky plain. Florida; Cuba; Hispaniola;
California.

PORTULACA HALIMOIDES L. ;

Frequent on the rocky plain. St. Jan; St. Croix:—Jamaica;
Cuba; Hispaniola; Porto Rico; St. Barts and St. Eustatius to
Martinique; Bonaire; Curacao; Aruba.

PORTULACA OLERACEA L.

Frequent on the rocky plain. St. Thomas; St. Jan:—conti;
nental temperate and tropical America; Bermuda; West Indies-
temperate and tropical regions of the Old World.

BRYOPHYLLUM PINNATUM (Lam.) Kurz.

Waste grounds near the settlement. Florida; Bermuda; West

Indies. Native of the Old World tropics.

572 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

PITHECOLOBIUM UNGuIS-cATI (L.) Mart.
Frequent on the rocky plain. St. Thomas; St. Jan:—Florida;
West Indies; Yucatan; northern South America.

Acacia anegadensis Britton, sp. nov.

An intricately branched tree, up to 8 m. high, the main branches
widely spreading, the slender twigs tortuous, glabrous. Stipules
a pair of rigid, acicular, persistent spines 5-15 mm. long; leaves
2-3 cm. long; petiole glabrous, or sparingly pubescent, 3-6 mm.
long, channeled above, bearing a sessile, saucer-shaped gland
about 0.5 mm. in diameter at the top; pinnae I-pair; petiolules a
little longer than the similar petiole, with a smaller, similar gland
between the leaflets; leaflets 1-pair, rarely 2-pairs, sessile, obliquely
oblong or oblong-obovate, coriaceous, glabrous, 10-16 mm. long,
strongly and loosely reticulate-veined, rounded or emarginate at
the apex, obliquely obtuse at the base, lustrous on both sides;
peduncles solitary or 2-4 together in the upper axils, slender,
loosely pubescent, shorter than the leaves; heads globose, in
flower 5-6 mm. in diameter; flowers yellow; calyx minutely
toothed, about 0.6 mm. long; corolla narrow, its teeth ciliolate,
much shorter than the tube; stamens about 20, 3-4 mm. long,
the filaments filiform, the anthers minute; pod short-stipitate,
linear, curved, apiculate, glabrous, veiny, 3-4 cm. long, swollen,
the dry, subcoriaceous valves very tardily dehiscent; seeds com-
pressed, suborbicular, brown, dull, 3-4 mm. in diameter, I.5 mm.
thick.

Abundant on the rocky plain, and occasional on the sandy plain
near the West End. (Type, Britton & Fishlock ogo.)

ACUAN VIRGATUM (L.) Medic.

Frequent on the rocky plain. Virgin Gorda; St. Thomas; St.
Croix; Culebra; Vieques:—Bermuda; West Indies; continental
tropical America.

CASSIA BICAPSULARIS L.
Occasional on the rocky plain. St. Thomas; St. Jan; Tortola;
Culebra; Vieques:—West Indies; continental tropical America.

CASSIA POLYPHYLLA Jacq.

Occasional on the rocky plain. St. Thomas; St. Croix:—Porto
Rico; Hispaniola.
CASSIA SOPHERA L.

Roadside, near the settlement; apparently introduced. West
Indies; continental tropical America and Old World tropics.

BRITTON: THE VEGETATION OF ANEGADA 573

SOPHERA TOMENTOSA L.

Frequent on the sandy plain, West End. St. Thomas; St.
Croix:—Florida; Bermuda; West Indies south to St. Vincent;
Aruba; continental tropical America and Old World tropics.
PICTETIA ACULEATA (Vahl) Urban.

Occasional on the rocky plain. Virgin Gorda; St. Jan; St.
Thomas; Culebra; Vieques:—Porto Rico; recorded from St.
Croix and, doubtfully, from Hispaniola.

STYLOSANTHES HAMATA (L.) Taubert.

Frequent on the rocky plain. Tortola; St. Thomas; St. Jan;
St. Croix:—Florida; West Indies south to Barbados; Mexico to
Colombia.

BRADBURYA VIRGINIANA (L.) Kuntze.

Frequent on the rocky plain. St. Thomas; Culebra; Vieques :—
southeastern United States; West Indies; continental tropical
America. Recorded from Bermuda.

BYRSONIMA LUCIDA (Sw.) DC. |

Frequent on the sandy plain, West End, and on the rocky plain.
St. Thomas; Vieques:—Florida; Bahamas; West Indies south to
Barbados.

MALPIGHIA LINEARIS Jacq.

On the rocky plain near the settlement. St. Jan; St. Thomas:—
south to Guadeloupe and Montserrat.
STIGMAPHYLLON LINGULATUM (Poir.) Small.

Frequent on the rocky plain. Tortola; St. Jan; St. Thomas;
Culebra; Vieques:—Hispaniola and Porto Rico to Martinique.
AMYRIS ELEMIFERA L.

Frequent of the rocky plain. St. Thomas; St. Jan: St. Crom:
Culebra; Vieques:—Florida; West Indies; Central America.
SURIANA MARITIMA L.

Frequent on sand dunes, West End. Virgin Gorda; St. Thomas;
‘St. Croix; St. Jan; Vieques:—Florida; Bermuda; West Indies;
continental tropical America and Old World tropics.

POLYGALA HECTACANTHA Urban.

Frequent on sand dunes, West End. Hispaniola; Porto Rico.
PHYLLANTHUS POLYCLADUS Urban.

Occasional on the rocky plain. Porto Rico; Hispaniola;
Bonaire; Curacao.

574 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

ARGYTHAMNIA STAHLII Urban.
Occasional on the rocky plain. Porto Rico.

CROTON DISCOLOR Willd.

Frequent on the sandy plain, West End, and occasional on the
rocky plain. Vieques; St. Thomas; St. Croix:—Hispaniola;
Mona; Porto Rico.

CHAMAESYCE BUXIFOLIA (Lam.) Small.

Sand dune, near East End. Virgin Gorda; St. Thomas; St.
Croix; St. Jan; Tortola:—Florida; Bermuda; West Indies; conti-
nental tropical America.

CHAMAESYCE SERPENS (H.B.K.) Small.

Rocky plain near the settlement. Porto Rico; St. Thomas:—
Antigua to Barbados; continental tropical America, north to
South Dakota.

CHAMAESYCE BLODGETTII (Engelm.) Small.
Rocky plain near the settlement. Florida; Bermuda; Bahamas;
Cuba; Jamaica.

CHAMAESYCE ANEGADENSIS Millsp. Field Mus. Bot. 2: 394.
1914.
Frequent on the rocky plain. Endemic.

Chamaesyce articulata (Aubl.) (Euphorbia articulata Aubl.)
Frequent on the sandy plain, West End. Tortola; St. Jan;

St. Thomas; Culebra; Vieques:—Porto Rico to St. Vincent.

AKLEMA PETIOLARIS (Sims) Millsp.
Frequent on the rocky plain. Tortola; St. Jan; St. Thomas;
Culebra; Vieques:—Hispaniola to St. Martin and Guadeloupe.

RHACOMA CROSSOPETALUM L.

Frequent on the sandy plain, West End. Virgin Gorda;
Tortola; Culebra; St. Thomas; St. Jan:—Florida; Bermuda;
West Indies; Colombia.

GYMINDA LATIFOLIA (Sw.) Urban.

Frequent on the sandy plain, West End. St. Thomas; Vieques:
—Florida; West Indies; Mexico.
ELAEODENDRON XYLOCARPUM (Vent.) DC.

Frequent on the sandy plain, West End. Tortola; St. Jan;
St. Thomas; St. Croix; Vieques; Culebra:—Porto Rico.

BRITTON: THE VEGETATION OF ANEGADA Sas,

SERJANIA POLYPHYLLA Radlk.

Frequent on the rocky plain. Tortola; St. Jan; St. Thomas;
Vieques; St. Croix:—Porto Rico; Hispaniola. Recorded from
Colombia.

DoDONAEA EHRENBERGII DC.

Common on the sandy plain, West End. Bahamas; Cuban
Cays; Hispaniola; Mona.
SARCOMPHALUS DOMINGENSIS (Spreng.) Urban.

Occasional on the rocky plain. Virgin Gorda; Tortola; Vieques:
—Hispaniola; Porto Rico; Anguilla.
COLUBRINA COLUBRINA (L.) Millsp.

Occasional on the rocky plain. Virgin Gorda; Tortola; St.
Thomas; St. Jan; St. Croix; Vieques; Culebra:—Florida; West
Indies south to Antigua; recorded from Barbados; Yucatan.

REYNOSIA UNCINATA Urban.

Frequent on the rocky plain. Tortola:—Porto Rico; Mona;
Anguilla.

CISSUS TRIFOLIATA L.

Frequent on the rocky plain. St. Jan; St. Thomas; St. Croix;
Vieques:—West Indies south to Martinique; northern South
America.

CORCHORUS HIRSUTUS L.

Frequent on the sandy plain, West End. Virgin Gorda;
Tortola; St. Jan; St. Thomas; St. Croix; Vieques:—West Indies
south to St. Eustatius; Bonaire; Curacao; Aruba.

SIDA CILIARIS L.

Occasional on the rocky plain. Virgin Gorda; Tortola; St. Jan;
St. Thomas; St. Croix:—Florida; West Indies, south to Bequia;
Margarita; Curacao; Aruba; continental tropical America.

PASSIFLORA SUBEROSA L.

Occasional on the rocky plain. St. Thomas; St. Croix; St. Jan;
Culebra; Vieques:—Florida; Bermuda; West Indies; continental
tropical America.

Cactus INToRTUS Mill.

Occasional on the rocky plain. Virgin Gorda; Tortola; St.
Jan; St. Thomas; St. Croix; Vieques:—Bahamas; Mona; Porto
Rico to Montserrat and Antigua.

576 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN >

CEPHALOCEREUS ROYENI (L.) Britton & Rose.

Frequent on the rocky plain. Virgin Gorda; Tortola; St. Jan;
St. Thomas; St. Croix; Culebra; Vieques:—Porto Rico; Mona;
Desecheo.

RHIZOPHORA MANGLE L.

Mangrove swamps, West End. St. Thomas; St. Croix; St.
Jan; Vieques:—Florida; Bermuda; West Indies; tropical conti-
nental America; west tropical Africa.

CONOCARPUS ERECTA Jacq.

Mangrove swamps, West End. Virgin Gorda; Tortola; St.
Thomas; St. Jan; St. Croix; Vieques:—Florida; Bermuda; West
Indies and continental tropical America.

LAGUNCULARIA RACEMOSA (L.) Gaertn. f.
Mangrove swamps, West End. St. Thomas; St. Jan; St. Croix;
Vieques:—Florida; West Indies; tropical continental America.

EUGENIA AXILLARIS (Sw.) Willd.

Sandy plain, West End. St. Croix; Vieques:—Florida; Ber-
muda; West Indies, south to Guadeloupe.

The determination is based on specimens showing foliage only.
The species is not recorded from Tortola, St. Jan, or St. Thomas.
BUMELIA OBOVATA (Lam.) A. DC.

A narrow-leaved race. Occasional on the sandy plain, West
End. Virein Gorda; Tortola; St. Jan; Si. Thomas; St,-Crom
Hispaniola to Santa Lucia; Bonaire; Curacao; Aruba. Recorded
from Jamaica.

JAcCQUINIA BarRBAsco (Loefl.) Mez.

Frequent on the sandy plain, West End. Tortola; St. Jan;
St. Thomas; St. Croix; Culebra; Vieques:—Jamaica; recorded
from Cuba; Porto Rico to Tobago; Curacao.

CENTAURIUM BRITTONII Millsp. & Greenm.

Shaded saline soil, West End. Bahamas.
PLUMIERA ALBA L.

Occasional on the rocky plain. Virgin Gorda; Tortola; St.
Jan; St. Thomas; St. Croix; Culebra; Vieques:—Porto Rico to
Grenada.

URECHITES LUTEA (L.) Britton.
Occasional on the sandy plain, West End. ‘Tortola; St. Jan;

BRITTON: THE VEGETATION OF ANEGADA Saez

St. Thomas; St. Croix; Vieques:—Florida; West Indies, south to
St. Kitts, and recorded from St. Vincent.
ASTEPHANUS.
Sandy plain, West End. Endemic.
EVOLVULUS GLABER Spreng.

Frequent on the rocky plain. Virgin Gorda; Tortola; St. Jan;
St. Thomas; St. Croix:—Florida; West Indies; tropical South
America.

EVOLVULUS SERICEUS Sw.

On the rocky plain near the settlement; a short-leaved, short-
sepaled race, occurring also on Anguilla, St. Martin, and Porto
Rico.

EVOLVULUS SQUAMOSUS Britton.

Occasional on the rocky plain. Bahamas.
JACQUEMONTIA RECLINATA House.

Sandy plain, West End. Florida; Bahamas.
MALLOTONIA GNAPHALODES (L.) Britton.

Frequent on sand dunes, West End. Virgin Gorda; St. Jan;
St. Thomas; St. Croix; Vieques:—Florida; Bermuda; West Indies;
Central America.

VARRONIA BAHAMENSIS (Urban) Millsp.
Frequent on the sandy plain, West End. Bahamas.

LANTANA INVOLUCRATA L.

Common on the sandy plain, West End. Tortola; St. Jan; St.
Thomas; Culebra; Vieques; St. Croix:—Florida; Bermuda; West
Indies; Mexico; Galapagos Islands.

VOLKAMERIA ACULEATA L.

Frequent on the rocky plain. Virgin Gorda; Tortola; St. Jan;
St. Thomas; St. Croix; Culebra:—Vieques; Bermuda; West Indies,
south to Martinique; continental tropical America.

CITHAREXYLUM FRUTICOSUM L.

Occasional on the rocky plain. Virgin Gorda; Tortola; St. Jan;
St. Thomas; Culebra; Vieques:—Florida; Bahamas; Jamaica;
Cuba; Hispaniola; Porto Rico to Dominica and Guadeloupe.

SALVIA SEROTINA L. (S. micrantha Vahl.)
Rocky plain, near the settlement. Tortola; St. Jan; St. Croix:—
Florida; Bermuda; West Indies; Yucatan.

578 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

SOLANUM PERSICIFOLIUM Dunal.

Occasional on the rocky plain. Virgin Gorda; Tortola; St.
Jan; St. Thomas; St. Croix; Culebra; Vieques:—Porto Rico.
LycIUM AMERICANUM Jacq.

Occasional on the rocky plain. Anguilla; Hispaniola; Cuba.
PHYSALIS ANGULATA L.

Occasional on the rocky plain. Tortola; St. Jan; St. Thomas;
St. Croix; Culebra; Vieques:—southern United States; Bermuda;
West Indies; continental tropical America.

TABEBUIA HETEROPHYLLA (DC.) Britton.
Occasional on the rocky plain. Virgin Gorda; St. Jan; St.
Thomas; St. Croix; Culebra; Vieques:—Porto Rico.

RANDIA ACULEATA L.

Frequent on the rocky plain. St. Jan; St. Thomas; St. Croix;
Vieques:—Florida; Bermuda; West Indies; Mexico. :
ERITHALIS FRUTICOSA L.

Common on the sandy plain, West End. Virgin Gorda; Tortola;
St. Jan; St. Thomas; St. Croix; Culebra; Vieques:—West Indies;
Central America.

STRUMPFIA MARITIMA Jacq.

Common on the sandy plain, West End. Tortola; Vieques:—
Florida; West Indies; south to Guadeloupe; Bonaire; Curacao;
Aruba; Yucatan.

ERNODEA LITTORALIS Sw.

Sandy plain, West End. Tortola; St. Jan; St. Thomas; St.
Croix; Culebra; Vieques:—West Indies, south to Guadeloupe;
Central America.

SPERMACOCE TENUIOR L.

Frequent on the rocky plain. St. Jan; St. Thomas; St. Croix;
Culebra; Vieques:—southern United States; Bermuda; West
Indies; continental tropical America.

Cucumis ANGURIA L.

On the rocky plain near the settlement. St. Jan; St. Thomas;
St. Croix; Culebra; Vieques:—Florida; West Indies; continental
tropical America.

SCAEVOLA PLUMIERI (L.) Vahl.
Frequent on sand dunes, West End. Virgin Gorda; Tortola;

BRITTON: THE VEGETATION OF ANEGADA 579

St, Thomas; St. Croix; Vieques:—Florida; Bermuda; West Indies;
Mexico; tropical Africa.
GUNDLACHIA CORYMBOSA (Urban) Britton.

Abundant on the sandy plain, West End. Bahamas; Porto
Rico to Guadeloupe; Curacao. Not known from the other
Virgin Islands, but found on Saba.

PLUCHEA PURPURASCENS (Sw.) DC.

Moist places on the rocky plain. St. Thomas; St. Croix =
southeastern United States; Bermuda; West Indies, south to
Guadeloupe; continental tropical America.

BORRICHIA ARBORESCENS (L.) DC.

Abundant in salinas, West End. St. Thomas; St. Croix;
Culebra; Vieques:—southeastern United States; Bermuda; West
Indies and continental tropical America.

WEDELIA PARVIFLORA L. C. Rich.

Frequent on the rocky plain. Tortola; St. Jan; St. Thomas;
St. Croix; Vieques; Culebra:—Porto Rico to Trinidad. _

BRYUM MICRODECURRENS E. G. Britton.

On the rocky plain near the settlement. Mona.
Hymenostomum BreuteEtit (C. Muell.) Broth.

On the rocky plain near the settlement. Tortola; St. Jan; St.
Thomas.

CHARA.
In a water hole near the settlement.

LICHENS
(Determined by Professor Lincoln W. Riddle.)

ARTHONIA INTERDUCTA Nyl.
On Acacia anegadensts.

Arthonia anegadensis Riddle, sp. nov.

Thallus epiphloeodes crustaceus sat crassus rimulosus laevi-
gatus niveus. Apothecia dispersa, rotundato-difformia aut sub-
elongata, diam. 0.2-0.5 mm., primum immersa vestitaque demum
aperta thallum subaequantia, disco plano epruinoso, sicco nigro,
madefacto badio, materias KOH reagentes haud continentia.
Epithecium fulvum; hymenium et hypothecium decoloratum;
hymenium iodo vinose rubens. Asci late ovales, octospori.
Sporae decolores vel subfuscescentes, oblongae, 6-loculares, cellulis
subaequalibus, 15-18 uw X 5-6 pz.

580 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

This is a striking and distinct species, belonging to the section
Euarthonia, and marked by the comparatively thick, rimulose,
very white thallus, in which are immersed the dark, difform
apothecia, with the disk slightly sunken below the surface of the
thallus.

Type: on bark of Pisonia subcordata, Anegada Island, West
Indies; coll. N. L. Britton and W. C. Fisklock, Feb. 19-20, 1913;
no. 987; in herb. L. W. Riddle. Duplicate in herb. New York
Botanical Garden.

RAMALINA DENTICULATA (Eschw.) Nyl.

On a twig.

BUELLIA PARASEMA var. AERUGINASCENS (Nyl.) Muell. Arg.

On a twig. |
ANTHRACOTHECIUM LIBRICOLUM (Fée) Muell. Arg.

On Acacia anegadensis.

ARTHOPYRENIA FALLAX (Nyl.) Arnold.

On Pisonia subcordata.

PyXINE MEISSNERI Tuck.
On a twig.

GLYPHIS CICATRICOSA Ach.
On a twig.

INDEX

Abies balsamifera, 480; concolor, 483;
grandis, 483; lasiocarpa, 478, 480,
481, 483

Abutilon Darwinii, 339, 340

Acacia, 306, 567, 568; anegadensis, 572,
579, 580; paradoxa, 274

Acer carolinianum, 80, 82, 84; Douglasii,
485; glabrum, 486; rubrum, 80

Achyranthes portoricensis, 571

Aconitum, 276

Acrochaetium, 113, 116, 120, 123; affine,
106, 108, I10, III, 115-120, 122; Hoytii,
112, 116-120, 122; Hyyneae, 120;
infestans, 116, I17, 122; robustum,
118, 120; unipes, 118-120

Aconitum, 557

Acuan virgatum, 572

Address of welcome, I

Aecidium Cerastii, 199; convolvulatum,
197; Galii ambiguum, 203; Giliae, 199;
gnaphaliatum, 205; graminellum, 180;
intermixtum, 204; Ipomoeae, 195; Ipo-
moeae-panduranae, 197; Leptotaeniae,
190; Ludwigiae, 189; monoicum, 188;
Nesaeae, 189; Phlogis, 199; Podophylli,
186; Pourthiaeae, 250; Sorbi, 251;
Swertiae, 195; Wilcoxianum, 199

Agalinis maritima, 86

Agaricus, 213, 215; alphitophorus, 510;
arvensis, 221, 222, 510; campestris,
221; corticola, 510; helictus, 510;
rhodocylix, 510; Rodmani, 212, 218,
221; tener, 510

Agastache, 163

Agave, 272, 305, 567; attenuata, 126;
missionum, 570; vivipara, 567

Agropyron molle, 490; Smithii, 490

Agrostis, 515

Akentra, 61

Aklema petiolaris, 574

Albugo, 197; candida, 502, 505

Alcyonidium gelatinosum, 117

Allium, 182, 254, 271, 305; reticulatum,
181

Allodus, 173-178, 181, 182, 196; ambigua,
177, 180, 203; areolata, 180, 186; asperior,
179, 193; Batesiana, 177, 180, 204; Bou-
vardiae, 179, 202; Calochorti, 179, 181;
Carnegiana, 179, 182, 183; Chamaesara-
chae, 177, 179, 201; claytoniata, 177, 179,
184, 185; commutata, 180, 203; con-
similis, 177, 180, 187; crassipes, 179,
196; Desmanthodii, 180, 206; Diche-
lostemmae, 180, 183, 184; Douglasii,

581

177, 180, 198; effusa, 174, 179, 188;
Erigeniae, 179, 191; gigantispora, 180,
185; Giliae, 177, 179, 199; gnaphaliata,
180, 205; graminella, 178, 180; imper-
spicua, 180, 189; insignis, 179, 197;
intermixta, 177, 179, 204; Jonesii,
179, 190; lacerata, 179, 194; Lindrothii,
179, 192; Ludwigiae, 180, 189; megalo-

spora, 179, 198; melanconioides, 180,
194; mellifera, 180, 200; microica,
180, 192; Moreniana, 179, 182; Musenii,
179, 193; Nesaeae, 189; nocticolor,
179, 197; Opposita, 180, 185; opulenta,
179, 195; oregonensis, 193; pagana,

179, 181; Palmeri, 179, 202; plumbaria,
199; Podophylli, 178, 179, 186; rufes-
cens, 179, 202; Senecionis, 207; suban-
gulata, 179, 183, 184; subcircinata,
180, 206; superflua, 179, 198; Swertiae,
180, 195; tenuis, 180, 205; vertisepta,
179, 201

Allodus, North American species of, 173

Allosorus crispus, 170

Alnus, 488; rugosa, 81; tenuifolia, 478,
483, 487; viridis, 480, 496

Aloe, 271, 305

Alstroemeria, 255

Alternanthera portoricensis, 571

Althaea, 274, 276, 306, 307; rosea, 273, 274

Amanita, 215; rubescens, 221

Amanitopsis, 215; vaginata, 221

Ambrosia, 284, 307; artemisiifolia, 284, 302

Amelanchier, 246, 487, 488, 497; alnifolia,
485; asiatica, 245; utahensis, 493

Amphilophis Torreyanus, 490

Amyris elemifera, 573

Andropogon scoparius, 490

Anegada, The vegetation of, 565

Anemone cylindrica, 185; globosa, 185,
186; narcissiflora, 185; nemorosa, 170;
patens Nuttalliana, 185

Aneura, 266, 288, 304

Anomalofilicites monstrosus, 474

Anona, 271, 278, 281

Anophthalmus, 66, 68

Antennaria dioica, 170

Anthericum, 257, 271, 305

Anthoceros, 255, 266, 267, 269, 274, 304

Antholyza, 271

Anthracothecium libricolum, 580

Antiquity among plants, Endemism as a
criterion of, I61

Antirrhinum majus,

358, 405

358, 405; molle,

582

Apicra, 271, 305

Apocynum, 271, 276, 281, 306

Aquilegia, 481, 482

Aranella, 43, 48, 49, 64; fimbriata, 48, 49

Arbacia, 432, 433

Arcella, 140

Arctostaphylos platyphylla,
ursi, 481

Arenaria verna, 169

Are Tetracentron, Trochodendron and
Drimys specialized or primitive types?,

493; Uva-

27
Argythamnia Stahlii, 574
Arisaema, 8; triphyllum, 81
Aristida, 515
Aristolochia, 271, 278, 306
Armeria vulgaris, 170
Armillaria mellea, 215, 221; mucida, 222
Arnica, 482
Aronia arbutifolia, 81; atropurpurea, 81
Arracacia Hartwegii, 192; multifida, 189,
190

Artemisia, 488; cana, 485; tridentata,
485, 493, 494 ,
Arthonia, 568; amnegadensis, 579; in-

terducta, 579

Arthopyrenia fallax, 580

Arundo, 566

Ascaris, 412

Asclepias, 270, 271, 276, 281, 282, 305

Ascobolus immersus, 506; stercorarius,
506

Ascophanus bermudensis, 502, 505; granu-
liformis, 506; sarcobius, 502, 505, 506

Asimina, 163

Askofake, 54

Asphodelus, 271, 305

Asplenium viride, 170

Astephanus, 568, 577

Aster, 463

Asterias, 433

Asterina pelliculosa, 507

Asterocarpus falcatus, 76; virginiensis, 76

Atkinson, GEO. F. The development
of Lepiota cristata and Lepiota semi-
nuda, 209

Atriplex confertifolia, 491, 494; hastata,
86

Audibertia incana, 200; grandiflora, 200;
stachyoides, 200

Aulospermum Betheli, 190; purpureum,
190

Avena sativa, 8

Avesicaria, 42, 56, 57, 64; neottioides, 56

Azalea nudiflora, 81; viscosa, 81

Baccharis, 84, 507

Baeria, 163

BaiLey, I. W., W. P. THompson and.
Are Tetracentron, Trochodendron and
Drimys specialized or primitive types?,
aH

BARNHART, Joun HENDLEY. Segrega-
tion of genera in Lentibulariaceae, 39

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Batis maritima, 570

Beat, W. J. Some things learned in
managing a botanic garden, 513

Beaufort, North Carolina, Notes on some
marine algae from the vicinity of, 105

Beets, Self, close and cross fertilization
of, 149

Benjaminia, 63

Benzoin aestivale, 81

Berberis Fremontii, 493

Bermuda fungi, 501

Beta, 407

Betula, 483, 488; fontinalis, 478, 483, 487;
occidentalis, 483; papyrifera, 481; utah-
ensis, 483

Bigelovia, 163

Bignonia, 306, 307; Leucoxylon, 567

Biovularia, 41, 57, 58, 64; cymbantha,
59; olivacea, 57, 59

BLAcK, CAROLINE A. The nature of the
inflorescence and fruit of Pyrus Malus,
519

BLAKESLEE, ALBERT F. Inheritable var-
iations in the yellow daisy (Rudbeckia
hirta), 89

Borrichia arborescens, 579

Botanical trip to North Wales in June,
Ar 167

Botanic garden, Some things learned in
managing a, 513

Botany, Directing factors in the teaching
of, 33

Botrychium, 267, 304

Botrytis cinerea, 325

Boudiera, 68

Bouteloua curtipendula, 490; eriopoda,
490; hirsuta, 490; oligostachya, 490;
polystachya, 490; prostrata, 490

Bouvardia triphylla, 203

Bradburya virginiana, 573

Brandonia, 47

Brassica, 515

Brickellia, 163

Britton, N. L. The vegetation of
Anegada, 565
Brodiaea, 174; capitata, 182; capitata

pauciflora, 183; congesta, 183, 184
Bromus, 515
Bryonia, 127, 137;.273) 270;-279,, 0
alba, 69, 70, 74; dioica, 69, 70, 74
Bryophyllum pinnatum, 571
Bryum microdecurrens, 579
Buellia parasema aeruginascens, 580
Bulbilis dactyloides, 490
Bullaria, 174-176
Bumelia obovata, 576
Byblis, 63
Byrsonima lucida, 573

Cabomba, 514

Cactus, 491; intortus, 575; missouriensis,
490; Viviparus, 490

Caeoma (Aecidium) claytoniatum
podophyllatum, 187; tenue, 205

184;

INDEX

Calla, 562

CALL, RICHARD ELLSworTH. Observa-
tions on the flora of Mammoth Cave,
Kentucky, 65

Calluna vulgaris, 170

Calochortus albus, 182; elegans, 182;
flavus, 182; Gunnisonii, 182; longebar-
batus, 182; nudus, 182; Nuttallii, 182

Calonectria granulosa, 504, 508; Um-
belliferarum, 504, 507

Calpidisca, 44, 54-56, 64; capensis, 56;
denticulata, 55, 56

Caltha biflora, 186; palustris, 171

Calycanthus, 535; floridus, 132

Calycocarpum, 163

Calyptospora, 178

Campanula rotundifolia, 170

Cardamine, 340, 350, 353, 384, 393, 402,
404, 407-409, 422, 427, 430, 431, 433,
439, 446; pratensis, 353, 440, 450

err 2739305; Collinsii, 81; Howei,

foe 163

Cassia bicapsularis, 572; polyphylla, 572;
Sophera, 572

Castilleja, 163, 482

Ceanothus, 163; Greggii, 493

Celtis crassifolia, 485; occidentalis, 485;
rugosa, 486

Centaurium Brittonii, 576

Cephalocerus Royeni, 576

Ceratophyllum, 271, 276, 281,

Ceratozamia, 268, 304

Cercocarpus, 164, 487, 493, 497; hypo-
leucus, 488; ledifolius, 488; montanus,
485, 486

Chaetomium, 508

Chamaecyparis, 79, 80, 82, 83, 86;
nootkatensis, 251; pisifera, 252; thy-
oides, 79

Chamaesaracha nana, 201

Chamaesyce 568; anegadensis, 568, 574;
articulata, 574; Blodgettii, 509, 574;
buxifolia, 574; hyssopifolia, 509; pros-
trata, 509; serpens, 574

Chantransia endozoica, 117

Chara, 579

Chemotropic reactions in Rhizopus nig-
ricans, 323

CHIVERS, ArTHUR H._ Directing factors
in the teaching of botany, 33

Chrysanthemum, 285, 299, 302, 307, 485,
488; frutescens, 284, 302

Chrysosplenium americanum,
positifolium, 172

Chrysothamnus, 488

Chylocladia, 260, 265

Cichorium, 340, 363, 364, 367, 384, 404,
405, 407, 408, 427, 432, 433, 441, 442,
446, 450; Intybus, 360, 364, 397, 401,

402, 409, 440, 447, 450, 454
Cichorium Intybus with reference to
sterility, Self- and _ cross-pollinations

in, 333

282, 305

172; Op-

583

Ciona, 348-351, 409, 433; intestinalis,
337, 348, 350, 407

Cissus trifoliata, 575

Citharexylum fruticosum, 577

Citrus, 335

Cladophora, 107, 258, 269, 277

Clathrus, 511

Claytonia asarifolia,
184; megarrhiza,
virginica, 184

Clethra alnifolia, 81

Cobaea, 279, 306, 307

Coccolobis Krugii, 571; Uvifera, 567, 571

Coelogyne, 493

Coemansia, 68

Cogswellia "foeniculacea, 190; Grayi, 190;
macrocarpa, 190; nevadensis, 190; orien-
talis, 190; platycarpa, 190; Suksdorfii,
190; triternata, 190

Colaconema, 113, 114; Bonnemaisoniae,
ae reticulatum, 114

Colacopsis, 113

Colletotrichum, 552-554, 556, 558; atra-
mentarium, 554- 560; solanicolum, 552,
554, 558

Colloidal systems, The embryo-sac and
pollen grain as, 561

Collomia gracilis, 200

Colubrina Colubrina, 575

Commelina elegans, 570

Conferva stellulata, 110

Conocarpus erecta, 576

Conocephalum, 266

Convallaria, 272, 305

Convolvulus, 273, 306

Cooperation in the investigation and
control of plant diseases, 517

Coprinus, 221, 224; ephemerus, 510;
fimetarius, 510; micaceus, 67, 221;
radians, 221

Corchorus hirsutus, 575

Cordyceps militaris, 507

Coriolus pavonius, 510;
510

Corydalis, 346; cava, 346, 438

Cosmiza, 41, 48-50, 64; coccinea, 49;
multifida, 48, 49

Covillea, 493, 494

Cowania, 493

Crataegus, 478, 485, 486, 488

Craterospermum, 260, 265

Crepis; 283; 284; 307;
129, 283; virens, 129

Crinipellis stupparia, 510

Cristatella, 45

Criterion of antiquity among plants,
Endemism as a, I61

Cross-pollination in Cichorium Intybus
with reference to sterility, Self- and, 333

Croton, 567; discolor, 567, 574

Cryptanthe, 163

Cryptotaenia canadensis, 192

Cucumis, 276, 306, 397; ‘Anguria, 578

Cucurbita, 306; Pepo, 273

caroliniana,
184;

184;
185; siberica,

sericeohirsutus,

taraxacifolia,

584 MEMOIRS OF THE NEW

Cyathus vernicosus, 68

Cycadeomyelon, 77

Cydonia, 246, 249, 250; japonica, 249;
vulgaris, 246, 247, 249

Cylindropuntia, 491

Cymopterus acaulis, 190; Fendleri, 190;
montanus, I9I; purpureus, 190; tere-
binthus, 191

Cynomarathrum Eastwoodii, 190

Cyperus brunneus, 569; cuspidatus, 569;
fuligineus, 569; elegans, 569

Cypripedium, 271, 305

Cypselea humifusa, 571

Cystopteris fragilis, 170

Cytisus Laburnum, 438

Cytokinesis of the pollen-mother-cells of
certain dicotyledons, 253

Dactyloctenium aegyptium, 568

Daedalea Aesculi, 510

Dahlia, 281, 306

Daldinia concentrica, 508

Daphne, 282, 306, 425

Darlingtonia, 163

Dasylirion, 491

Dasyscypha earoleuca, 506

Dasyspora, 173-175, 185,
Anemones-virginianae, 185

Delphinium, 276

Dendropemon caribaeus, 570

Derbesia repens, 107; turbinata, 106-108,
121; vaucheriaeformis, 107, 108

Deringa canadensis, 192

Desmanthodium fruticosum, 206; ovatum,
206

Desmarestia Dudresnayi, 114

Detonia Planchonis, 503

Development of Lepiota cristata and
Lepiota seminuda, The, 209

Deweya arguta, 192

188, 192;

Dicaeoma, 174, 175, 188, 194, 195;
anachoreticum, 181; arabicola, 199;
areolatum, 186; asperius, 193; clay-

toniatum, 184, Clematidis, 185; con-
simile, 187; crassipes, 196; Cymopteri,
190; Douglasii, 198; fragile, 199;
Holwayi, 181; intermixtum, 204; in-
vestitum, 205; Ipomoeae, 196; Jonesii,
190; melanconioides, 194; microicum,

192; Nesaeae, 189; opulentum, 195;
plumbarium, 199; Podophylli, 187;
rufescens, 202; subcircinatum, 206;

Swertiae, 195; Violae, 188; tenue, 205
Dichelostemma congestum, 183, 184
Dichondra carolinensis, 509
Dicotyledons, Cytokinesis of the pollen-

mother-cells of certain, 253
Dictyopteris polypodioides, 108
Dictyota, 108, 122, 123, 255, 259, 260;

dichotoma, 105, 106, I108-I12, II5,

116, 118; linearis, 118
Didymium, 261
Dimerosporium melioloides, 507
Diorchidium Tracyi, 201

YORK BOTANICAL GARDEN

Dipterostemon capitatus, 182, 183; pauci-
florus, 183

Dirca, 163

Directing factors
botany, 33

Distichlis spicata, 85, 86

Diurospermum, 50

Dodecatheon, 195; cruciatum, 195; Hen-
dersonii, 195; latifolium, 195; ‘‘ Meadia,”

in the teaching of

195

Dodonaea Ehrenbergii, 575

Drimys, 27-30; axillaris, 29-31; colorata,
29-31; Muelleri, 27; vascularis, 27;
Winteri, 29-31

Drimys specialized or primitive types?
Are Tetracentron, Trochodendron and,
27

Drosera, 134, 137, 142, 282, 306; binata,
130, 138; filiformis, 130, 132-134, 136-
138, 146; intermedia, 130, 132, 134,
137, 138, 141, 146; longifolia, 125, 129-
133, 138, 141, 147; obovata, 125, 126,
128, 141; rotundifolia, 125, 130-132,
134, 137, 138, 141, 146, 172

Drosera, Somatic and reduction divisions
in certain species of, 125

Drudeophytum Hartwegii, 192

Dryas octopetala, 170

Dryopteris simulata, 81

Echinis, 433

Echinocactus, 491

Echinocereus, 491

Echinopanax horrida, 482

Ecology and the new soil fertility, Plant,
319

Ectocarpus solitarius, 108

Elachistea, 108; stellulata,
IIO-I12, 115, 118

Elaeodendron xylocarpum, 574

Embryo-sac and pollen grain as colloidal
systems, The, 561

Empetrum nigrum, 170

Endemism as a criterion of antiquity
among plants, 161

Enskide, 54

Ephedra, 254, 269, 493

Epidendrum, 567; papilionaceum, 570

Epigaea repens, 139

Epilobium, 272, 305

Epipactis, 254, 305

Equisetum, 267, 304, 308, 461, 463, 464;
arvense, 464; arvense boreale, 461;
Funstoni, 471; Funstoni caespitosum,
471; Funstoni polystachyum, 471; hye-
male, 463, 468; hyemale affine, 468;
hyemale californicum, 465, 467; hye-
male Doellii, 465; hyemale Drummondi,
467; hyemale herbaceum, 471; hyemale
intermedium, 468, 470; hyemale preal-
tum, 467; hyemale pumilum, 468;
hyemale robustum, 467; hyemale Suks-
dorfi, 468; hyemale texanum, 469;
laevigatum, 461, 469; laevigatum poly-

106, 108,

INDEX

stachyum, 472; laevigatum scabrellum,
469; laevigatum variegatoides, 471;
limosum, 466, 469; prealtum, 467;
ramosissimum, 463; robustum, 461,
467; robustum afhne, 467; robustum
minus, 467; scirpoides, 467; variegatum,
466; variegatum alaskanum, 466; varie-
gatum anceps, 466; variegatum Jesupi,
465; variegatum Nelsoni, 472

Eragrostis ciliaris, 568; Urbaniana, 569

Erigenia bulbosa, 191

Erinella rhaphidophora, 506

Eriogonum, 163, 491, 494

Erioneuron pilosum, 491

Eriophyllum, 163

Erithalis fruticosa, 578

Ernodea littoralis, 578

Erythrocladia, 113, 114, 120; irregularis,

II2, 113; recondita, 112, 114-116,
120-122; vagabunda, 115, 116, 118,
120-122

Erythrotrichia, 113, I14; carnea, 114;
obscura, 114

Eschscholtzia 341, 342, 402-404, 407,
417-419, 422, 562; californica, 339,
344, 440, 446, 562

Euarthonia, 580

Eubotrys racemosa, 81

Eugenia, 567; axillaris, 576

Eupatorium ageratoides, 205; urticae-

folium, 205
Euphorbia articulata, 574; corollata, 126
Eurotia, 488
Evolvulus_ glaber, sericeus,
squamosus, 577
Exogonium arenarium, 196
Exploration in Southern Florida, Recent,

475
Fallugia, 493

5773 5773

FARR, CLIFFORD HARRISON. Cytokinesis

of the pollen-mother-cells of certain
dicotyledons, 253

FARWELL, OLIVER ATKINS. The genus
Hippochaete in North America, north
of Mexico, 461

Fegatella, 266, 304

Fendlera, 493

Fern monstrosity, A fossil, 473

Fertility, Plant ecology and the new soil,

319
Fertilization of beets, Self, close and
cross, 149

Ferula dissoluta, 193; multifida, 191;
purpurea, I9I

Festuca, 515

Fimbristylis inaguensis, 569

Fimetaria fimicola, 508; hyalina, 508

Flora of Mammoth Cave, Kentucky,

Observations on the, 65
Flustra foliacea, 114
Foeniculum, 504; Foeniculum, 507
Fomes applanatus, 67; Sagraeanus, 510
Fossil fern monstrosity, A, 473

585

Fossombronia, 266

Fourcroya macrophylla, 509

Fraxinus anomala, 478, 493; campestris,
485

Freesia, 271, 305

Fritillaria, 271, 305

Fruit of Pyrus Malus, The nature of the
inflorescence and, 519

Fuchsia, 126

Fucus, 106, 256, 260, 264

Fuligo, 261

Funaria, 267, 304

Fungi, Bermuda, 501

Funkia, 272, 305

Furcraea, 567; tuberosa, 570

Fusarium, 551, 555-557, 559

GaAGER, C. STuART. Present status of
the problem of the effect of radium
rays on plant life, 153

Galium Aparine, 177, 203; boreale, 170

Galtonia, 271, 272; candicans, 129

Garrya, 163

Gasteria, 271, 305

Gaylussacia frondosa, 81

Geaster saccatus, 511

Genlisea, 41, 48, 64; aurea, 48; filiformis,
48

Geoglossum nigritum, 502, 505; pumilum,
595

Gilia californica, 200; ciliata, 199; gracilis,
200; Nuttallii, 200

Ginkgo biloba, 29, 31

Gladiolus, 351

Glaucium, 276

Glyphis cicatricosa, 580

Gnaphalium californicum, 206; decurrens,
206; leptophyllum, 206; leucocephalum,
206; margaritaceum, 206; obtusifolium,
206; oxyphyllum, 206; polycephalum,
206; semiamplexicaule, 206

Gnetum, 27

Goniotrichum, 114

Gonium, 300

Gorgoniceps Pumilionis, 506

Gossypium, 307

Graves, ArtHUR H. A botanical trip
to North Wales in June, 167; Chemo-
tropic reactions in Rhizopus nigricans,
323

Graya, 494

Grossularia odorata, 490; setosa, 485

Growth, The mechanism and conditions

of, 5

Gundlachia corymbosa, 579

Gyminda latifolia, 574

Gymnoascus setosus, 68

Gymnopilus penetrans, 510

Gymnosporangium, 178, 245-249, 251;
asiaticum, 247, 249; bermudianum,
510; Blasdaleanum, 250, 251; chinense,
247, 249; fraternum, 249; Haraeanum,
247, 249; japonicum, 245-247, 249;
koreaense, 248-250; macropus, 516;

586

Miyabei, 252; Nidus-avis, 246; noot-
katense, 178; Photiniae, 246, 247, 249,
250; spiniferum, 246; solenoides, 252;
Yamadae, 250

Gymnosporangium, Japanese species of,
245

Hamamelis, 283, 307; virginiana, 81

Hamulia, 60

Harper, R. A. On the nature of types
in Pediastrum, 91

Harris, J. ArtHur. A _ tetracotyledon-
ous race of Phaseolus vulgaris, 229

Haworthia, 271, 305

Helianthus, 8, 25, 285, 302, 307, 515;
annuus, 284; globosus, 8

Helicoma larvula, 509

Helicopsis helianthoides, 205; scabra, 205

Helleborus, 269

Helminthosporium Ravenelii, 509

Helvella crispa, 129

Hemerocallis, 258, 271, 273, 302, 305;
flava, 347; fulva, 126, 127

Hemizonia, 163

Hesperis, 306; matronalis, 281

Heuchera, 163

Heyderia, 251; decurrens, 250

Hieracium, 306; venosum, 282

Hippochaete, 462-464; hyemalis, 462-
465; hyemalis alaskana, 462, 464, 466;
hyemalis californica, 462, 464, 465, 468;
hyemalis Jesupi, 463-465, 472; laevi-
gata, 462, 463, 465, 466, 468-472;
laevigata Eatonii, 465, 470; laevigata
Funstoni, 463, 465, 471; laevigata
polystachya, 465, 471; Nelsoni, 465,
472; prealta, 462-464, 467-470; prealta
affinis, 462, 464, 467-470; prealta
intermedia, 465, 468, 470; prealta
scabrella, 465, 469; prealta Suksdorfi,
465, 468; ramosissima, 463; scirpoides,
462-464, 466, 467; variegata, 462,
464-467, 469; variegata anceps, 463,
464, 466

Hippochaete in North America, north of
Mexico, The genus, 461

Hirneola coffeicolor, 510

Ho.iick, ArtHuR. A fossil fern mon-
strosity, 473

Hookera pulchella, 183, 184

Houttuynia, 278, 306

Howe, MArsHALL AVERY, and WILLIAM
Dana Hoyt. Notes on some marine
algae from the vicinity of Beaufort,
North Carolina, 105

Hoyt, WitLt1AM Dana, MARSHALL AVERY
Howe and, Notes on some marine
algae irom the vicinity of Beaufort,
North Carolina, 105

Humpureys, Epwin W. Triassic plants
from Sonora, Mexico, including a
Neocalamites not previously reported
from North America, 75

Hydrion, 61, 63

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Hydrocybe Cantharellus, 510; conica,
510

Hymenopappus, 163

Hymenophyllum Wilsoni, 170

Hymenostomum Breutelii, 579

Hypholoma fasciculare, 221; sublateritium,
221

Hypocrea patella, 507

Hypoxylon fuscopurpureum, 508; fuscum,
508; investiens, 508; multiforme, 508

Hysterographium lineolatum, 506; prae-
longum, 506

Ibidium lucayanum, 570
ar glabra, 81; laevigata, 81; verticillata,
I

Ilicioides mucronata, 81

Inflorescence and fruit of Pyrus Malus,
The nature of the, 519

Inheritable variations in the yellow daisy
(Rudbeckia hirta), 89

Investigation and control of plant dis-
eases, Cooperation in, 517

Ipomoea, 173, 196, 197, 284, 306, 342,
415, 417, 418, 509; acuminata, 196;
arborescens, 198; arenaria, 196; caro-
lina, 196, 198; caroliniana, 196; cathar-
tica, 196; commutata, 196; fastigiata,
196; fistulosa, 197; intrapilosa, 197,
198; Jalapa, 196; murucoides, 198;
purga, 196; purpurea, 196; Steudeli,
196; tiliacea, 196; trichocarpa, 196;
tricolor, 281; triloba, 196; Wolcottiana,
197

Iris, 270, 271, 275, 305; pumila, 126

Isaria felina, 509

Isoetes, 268, 269, 304, 308; lacustris, 171

Isoloba, 46, 47

Iva, 84; axillaris, 204

. Ixia, 271, 305

Jacquemontia reclinata, 577

Jacquinia Barbasco, 576

Japanese species of Gymnosporangium,
245

Jasminum, 504, 508

Juncus Gerardi, 85

Juniperus, 247; barbadensis, 510; chinen-
sis, 245-250; communis, 170; communis
montana, 170; virginiana, 84

Karschia lignyota, 506

KELLERMAN, Kart F. Cooperation in
the investigation and control of plant
diseases, 517

KERN, Frank D. Japanese species of
Gymnosporangium, 245

Knowledge of silver scurf (Spondylo-
cladium atrovirens Harz) of the white
potato, A contribution to our, 549

Koeleria nitida, 490

Krigia, 163

Laboulbenia, 68; subterranea, 66, 68

INDEX

Lachnea pulcherrima, 505; theleboloides,
595 y

Laguncularia racemosa, 576

Laminaria, 537

Lamprospora Planchonis, 505

Lantana involucrata, 577; odorata, 504,
597, 509

Larix, 256, 284, 305; laricina, 480; Lyallii,
480, 481; occidentalis, 483

Lasiobolus equinus, 506

Lasiosphaeria pezizula, 508

Lathyrus, 283, 306; odoratus, 281

Laurus Culilaban, 567

Lavatera, 279, 306, 307

Leavenworthia, 163

Lecticula, 44, 57, 58, 64; resupinata, 57,
58; Spruceana, 58

Lentibularia, 39, 60

Lentibulariaceae, Segregation of genera
in, 39

Lepargyraea canadensis, 481

Lepiactis, 60

Lepiota, 214, 222; clypeolaria, 215, 222;
cristata, 210, 213, 216, 221-224, 226;
naucina, 510; seminuda, 210, 213, 216,
218, 222-224, 226,227,

Lepiota cristata and Lepiota seminuda,
The development of, 209

Lepiota seminuda, The development of
Lepiota cristata and, 209

Leptodactylon californicum, Nut-
tallii, 200

Leptotaenia, 193; dissecta, 193; Eatonii,
190; multifida, 191; purpurea, I9I

Lesquerella, 163, 491

LEVINE, MICHAEL. Somatic and _ re-
duction divisions in certain species of
Drosera, 125

Libocedrus decurrens, 250

Lilium 134, 255, 269, 271, 272, 280, 284,
305, 336, 442; bulbiferum, 351; cana-
dense, 81, 128; candidum, 129

Limax, 262.

Limonium carolinianum, 85, 86

Limosina stygia, 67

Linanthus ciliatus, 200

Linnaea americana, 481

Linum catharticum, 155; grandiflorum,
442, 444, 447-

LipMAN, Cuas. B. Plant ecology and the
new soil fertility, 319

Lippia, 507

Liriodendron, 271, 277

Litanthus, 42

Lithophila muscoides, 571

Littorella lacustris, 171

Lioyp, Francis E. The embryo-sac
and pollen grainas colloidal systems, 561

Lloydia serotina, 171

Lobelia Dortmanna, 171

Lomatium foeniculaceum, 190; Grayi,
190; macrocarpum, 190; orientale, 190;
platycarpum, 190; Suksdorfii, 190;
triternatum, 190

200;

587

Lonchocarpus violaceus, 509

Lonicera, 481

Ludwigia alternifolia, 189; glandulosa,
189; hirtella, 189; palustris, 189; poly-
carpa, 189; sphaerocarpa, 189; virgata,
18

Lychnis dioica, 169
Lycium americanum, 578
Lycopodium, 268
Lygodesmia, 163
Lymantria dispar, 72
Lythrum, 336, 433, 441,

441, 443, 444, 447

MacDouca., D. T. The mechanism and
conditions ‘of growth, 5

Maclura, 163

Macroceras, 53

Macrosporium Solani, 509

Macrotaeniopteris, 76; magnifolia, 76

Madia, 163

Magnolia, 80, 81, 271, 277, 278, 281

Mallotonia gnaphalodes, 577

Malpighia, 567; angustifolia, 567; coc-

cifera, 567; linearis, 567, 573; urens, 567

Malus, 250, 536; Malus, 250; spectabilis,
250; Toringo, 250

Mammoth Cave, Kentucky,
tions on the flora of, 65

Managing a botanic garden, Some things
learned in, 513

Marasmius, 222; bermudensis, 510; minu-
tus, 510; obscurus, 510; praedecurrens,
511; Sabali, 510

Marine algae from the vicinity of Beau-
fort, North Carolina, 105

Mariscus jamaicensis, 507, 509

Marsilea, 268, 304

Matricaria Chamomilla, 129, 283

Matthiola, 335

Mechanism and conditions of growth,
The, 5

Medicago denticulata, 509

Megozipa, 60

Meionula, 50, 52

Melanospora ornata, 555

Meliola Cookeana, 507; circinans, "507

Meloneura, 42, 43, 45, 50, 51, 64; pur-
purea, 50; striatula, 50, 51

Menyanthes trifoliata, 171

Mercurialis, 71, 73, 74; annua, 70-74

Mercurialis annua, Observations on in-

heritance of sex-ratios in, 69

Merrick, Long Island, and its significances

A white-cedar swamp at, 79

Mertensides, 76; bullatus, 76

Mespilus, 535

Micranthemum, 63

Microascus longirostris, 68

Microchaete nana, 105, I06, III, 115,
118, 122; purpurea, 106; vitiensis, 106

Microseris, 163

Microsteris gracilis, 200; humilis, 200;
micrantha, 200

444; Salicaria,

Observa-

588

Mimosa, 567

Mimulus, 342, 415, 417, 418

Mirabilis, 279, 306; Jalapa, 336;
flora, 336

Mitchella repens, 81

Momordica, 306; Elaterium, 273

Monbretia, 271, 305

Monstrosity, A fossil fern, 473

Montia asarifolia, 184; siberica, 184

Mougeotia, 260, 265

Mucor, 66, 502, 505; Mucedo, 66, 68

Musa, 273; 305; sapientum, 127

Musenion tenuifolium, 194

Musineon divaricatum, 191; Hookeri, 191;
tenuifolium, 194; trachyspermum, I9QI

Myriactis stellulata, 110

Myrica carolinensis, 84; Gale, 172

Myriophyllum, 63

longi-

Naias, 305; major, 270

Nature of types in Pediastrum, On the, 91

Navicula, 66

Nectria Lantanae, 503, 507; sanguinea,
597

Neevea, I14

Negundo interior, 485

Nelipus, 54

Nemopanthus, 163; mucronata, 81

Neobeckia, 6; aquatica, 6

Neocalamites Carrerei, 77, 78

Neocalamites not previously reported
from North America, Triassic plants
from Sonora, Mexico, including a, 75

Neotoma, 66

Neottia, 305; ovata, 270

Nepenthes, 538

Nephrolepis exaltata, 473, 474

Nereis, 432, 433

Nicotiana, 137, 282, 285, 286, 290, 293-
295, 297, 301, 302, 307, 316, 340, 358,
360, 407, 409, 422; alata grandiflora,
358, 420, 423; Forgetiana, 358, 420,
423; paniculata, 423; rustica, 423;
Tabacum, 284

Nigredo Medicaginis, 509; proeminens,
509

Nolina, 491

North America, north of Mexico, The
genus Hippochaete in, 461

North American species of Allodus, 173

North Wales in June, A botanical trip to,
167

Norton, J. B. S. Variation in Tithy-
malopsis, 455

Notes on some marine algae from the
vicinity of Beaufort, North Carolina,
105

Nummularia Bulliardi, 508

Nymphaea, 270, 276, 306

Nyssa, 82, 84; sylvatica, 80

Observations on inheritance of sex-ratios
in Mercurialis annua, 69

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Observations on the flora of Mammoth
Cave, Kentucky, 65

Odostemon aquifolium, 482

Oedipodium Griffithianum, 172

Oedogonium, 258, 537

Oenothera, 134, 273, 284, 306, 307, 364;
biennis, 129; gigas, 127, 128, 129;
Lamarckiana, 127, 335; lata, 127, 335;
semilata, 127

Oleander, 509

On the nature of types in Pediastrum, 91

Oospora rosea, 555

Ophiobolus acuminatus, 509

Opuntia, 14, 491, 509; arborescens, 491;
Blakeana, 14, 15, 18, 19, 22; discata,
II, 22, 26; fragilis, 490; polyacantha,
490

Orbilia chrysocoma, 506

Orcheosanthus, 46, 47

Orchis, 305; Morio, 270

Orchyllium, 53-56, 64; alpinum, 53, 55

Oreoxis humilis, 194

Orthocarpus, 163

Orton, C. R. North American species
of Allodus, 173

Osmunda, 267, 304

Ostrya virginica, 485, 489

Otozamites Macombii, 77

Oxalis Acetosella, 170

Oxyria digyna, 168

Pachira, 229

Pachystima Myrsinites, 482

Padus, 491; melanocarpa,
valida, 486

Pallavicinia, 266, 304

Palissya, 78

Panaeolus campanulatus, 511

Panicularia obtusa, 81

Panicum, 515; geminatum, 568

Papulospora, 68

Parnassia, 282, 307

Parthenocissus quinquefolia, 81

Paspalum Helleri, 569

Passiflora, 274, 275, 306, 351; alata, 3513
caerulea, 126; suberosa, 575

Patellaria atrata, 506

Pecopteris bullata, 76; falcatus, 7

Pediastrum, 91-93, 95, 102-104; Bory-
anum, OI, 94, 95, 97-100, 102, 104

Pediastrum, On the nature of types in, 91

Pedicularis canadensis, 202; centranthera,
202; semibarbatus, 202

Pelargonium, 335

Pelidnia, 42, 50-52, 64; caerulea, 50, 51

Pellia, 265, 304

Peltandra, 272, 305

Pemphiginia, 62, 63

Penicillium, 325

Pentstemon, 163, 482; chionophilus, 202;
confertus, 202; Harbourii, 202; humilis,
202; Menziesii, 202; Newberryi, 202;
ovatus, 202; pinetorum, 202

Periola tomentosa, 554

486, 490;

INDEX

Persicaria punctata, 509

Personula, 54

Petradoria, 493

Petunia, 335

Pestalozzia Guepini, 509

Peucedanum foeniculaceum, 190; Grayi,
190; macrocarpum, 190; nevadense,
190; nudicaule, 190; simplex, 190, 191;
Suksdorfii, 190; triternatum, 190

Phabartis cathartica, 196

Phaeostroma, 110; pusillum, 106, 108—-IIT,
118, 121; pustulosum, I10

Phascum, 267

Phaseolus, 255; vulgaris, 242, 243

Phaseolus vulgaris, A tetracotyledonous
race of, 229

Phegopteris Dryopteris, 170; polypodio-
ides, 170

Phellomyces, 549, 551-553, 558; sclerotio-
phorus, 549-552, 554, 558

Phellopterus montanus, I9I

Philoxerus vermicularis, 571

Phlox alyssifolia, 199; depressa, 199;
diapensioides, 199; diffusa, 199; divari-
cata, 200; Douglasii, 199; longifolia,
200; multiflora, 200; speciosa, 200;
Stansburyii, 200

Phoma leguminum,
509; Musarum, 509

Phormidium, 117

Photinia laevis, 246; villosa, 246

Phycomyces, 8, 23, 25

Phycophila stellulata, 110, III

Phyllanthus polycladus, 573

Phyllaria, 50

Phyllosticta. Ipomoeae, 509; Opuntiae,

509; Fourcroyae,

509

Physalis angulata, 578

Picea, 269; albertiana, 483; canadensis,
480; Engelmanni, 478, 480, 481, 483;
Mariana, 480; Parryana, 478, 483

Pictetia aculeata, 567, 573

Pilea tenerrima, 570; trianthemoides, 570

Pilobolus crystallinus, 502, 505

Pimpinella Saxifraga, 170

Pinguicula, 40, 41, 44, 46, 63, 64; caudata,
46; crenatiloba, 46, 47; lusitanica, 46;
pumila, 46; vulgaris, 46, 172

Pinus, 269, 305; albicaulis, 480, 481, 483;
aristata, 478, 480, 481, 483; Banksiana,
481; edulis, 478, 487, 493; flexilis, 478,
483; monophylla, 478, 487, 493; mon-
tana, 480; monticola, 483, 496; Mur-
rayana, 478, 483; palustris, 29, 31;
ponderosa, 483, 488; resinosa, 481;
scopulorum, 478, 481, 483, 485, 486,
488, 497; Strobus, 481

Pionophyllum, 46, 47

Pisonia subcordata, 571, 580

Pisum, 306; sativum, 281

Pithecolobium Unguis-cati, 572

Pithya Cupressi, 505

Plagiochasma, 266

Planera, 163

589

Plantago, 427; lanceolata, 73, 427; major
halophila, 85; maritima, 85, 86

Plant diseases, Cooperation in the in-
vestigation and control of, 517

Plant ecology and the new soil fertility,

319

Plant life, Present status of the problem
of the effect of radium rays on, 153

Plectoma, 60

Pleiochasia, 42, 51-53, 64; dichotoma,
51, 53

Plesisa, 60

Pleurage anserina, 508; fimiseda, 508;
vestita, 508

Pleurotopsis niduliformis, 511

Pluchea purpurascens, 579

Plumiera alba, 576

Poa, 515

Podophyllum, 280, 306, 307; peltatum,
178, 187

Poinsettia heterophylla, 509

Pollen grain as colloidal systems, The
embryo-sac and, 561

Pollen-mother-cells of certain dicoty-
ledons, Cytokinesis of the, 253

Polygala hectacantha, 573

Polygonum, 515

Polypodium, 267; vulgare, 129

Polypompholyx, 41, 49; laciniata, 50

Polyporus arcularius, 511; obliquus, 511

Polysiphonia urceolata, 112, 113

Polytrichum, 294

Populus, 478, 483, 488; acuminata, 485,
487; angustifolia, 483, 485, 487; aurea,
482; balsamifera, 481, 483; Fremontii,
478; Sargentii, 485, 487; tremuloides,
480, 481, 483; trichocarpa, 483; Wis-
lizeni, 478, 487

Poronia Oedipus, 509

Portulaca halimoides, 571; oleracea, 571

Potamogeton, 272, 305

Potentilla, 127, 279; canadensis,
pumila, 172; Tormentilla, 172

Pourthiaea, 246, 249; villosa, 245, 246, 250

Present status of the problem of the effect
of radium rays on plant life, 153

Primula, 283, 285, 302, 303, 306, 433) 441;
442, 444, 445; kewensis, 129; sinensis,
284, 342, 444, 450; veris, 169, 342, 444

Propolis faginea, 50

Prosopis, 494

Prunus, 536; americana, 485; melanocarpa,
485

Pseudocymopterus anisatus,
natus, 194

Pseudotsuga mucronata, 478, 483-486

Psilotum, 268, 304

Ptelea, 163

Pteris, 254, 267, 304

Pterospora, 163

Pteryxia calcarea, I91; terebinthina, 191

Puccinia aculeata, 186, 187; ambigua,
203; anachoreta, 181; arabicola, 199;
areolata, 186; asperior, 193; aurea,

1725

194; bipin-

590

187; Batesiana, 204; Bouvardiae, 202;
Calochorti, 181; Carnegiana, 182; Cha-
maesarachae, 201; Cladii, 504, 509;
claytoniata, 184; commutata, 203; con-
similis, 187; crassipes, 196; Crypto-
taeniae, 192; Cymopteri, 190; deBary-
ana, 185; depressa, 199; Desmanthodii,
206; Dichelostemmae, 183; Dichondrae,

509; difformis, 203; Douglasii, 198;
effusa, 188; fragilis, 199; gigantispora,
185; giliicola, 199; graminella, 180;
Holboellii, 188; Holwayi, 181; imper-
spicua, 189; insignis, 197; intermixta,
204; investita, 205; Ipomoeae, 196;
japonica, 186; Jonesii, 190; Lantanae,

509; Lindrothii, 192; Ludwigiae, 189;
Mariae-Wilsoni, 184; melanconioides,
194; mellifera, 200; microica, 192;
Moreniana, 182; Musenii, 193; Nesaeae,
189; nocticolor, 197; nodosa, 182, 183;
obtegens, 176; opulenta, 195; oregonen-
sis, 193; pagana, 181; Palmeri, 202;
plumbaria, 199; plumbaria phlogina,
199; Podophylli, 176, 178, 186, 187;
Polygoni-amphibil, 509; purpurea, 510;
Purpusii, 199; Richardsoni, 198; rufes-
cens, 202; Saniculae. 194; Seymourii,
193; sphalerocondra, 192; subangulata,
183; subcircinata, 206; subulata, 199;
superflua, 198; Swertiae, 195; tenuis,
205; Traversiana, 190; tumamocensis,
183; vertisepta, 201; Wilcoxiana, 199

Pyrola, 481

Pyronema omphalodes, 503, 506

Pyrus, 245, 250, 524, 534, 535; Aucuparia,
170; Malus, 245, 250, 519, 524, 526;
Miyabei, 251, 252; sinensis, 245-247,
249; spectabilis, 250; Toringo, 250

Pyrus Malus, The nature of the inflores-
cence and fruit of, 519

Pyxine Meissneri, 580

Quercus, 493; Gambelii, 478, 487; mac-
rocarpa, 485, 489; rubra, 80; stellata,
84; undulata, 478

Quinquelobus, 63

Race of Phaseolus vulgaris, A tetracotyl-
deonous, 229

Radium rays on plant life, Present status
of the problem of the effect of, 153

Rafflesia, 271, 276, 281, 305

Ramalina denticulata, 580

Randia aculeata, 578

Ranunculus Flammula, 171

Reactions in Rhizopus nigricans, Chemo-
tropic, 323

Recent exploration in southern Florida,
af 2. Mae ee ;

Reduction divisions in certain species of
Drosera, Somatic and, 125

Reseda, 350, 358, 402, 404, 407, 417-419,
427; lutea, 339, 340; odorata, 339-341

Reynosia uncinata, 575

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

Rhacoma crossopetalum, 574

Rhizomorpha molinaris, 67, 68

Rhizophora Mangle, 509, 567, 576

Rhizopus, 324-326; nigricans, 325

Rhizopus nigricans, Chemotropic reactions
in, 323

Rhododendron, 81, 480; maximum, 80

Rhus, 491; copallina, 84; trilobata, 485,
486, 490

Ribes, 279, 306, 487; Gordonianum, 127;
inebrians, 485, 486; odoratum, 485

Riccardia, 266

Robinia, 163; neomexicana, 486; squamata
567

Rocky Mountain region, Vegetative life
zones of the, 477

Roestelia, 246, 250, 252; koreaensis,
245-249; Photiniae, 246, 250; solenoides,
251; solitaria, 251

Rosa, 487; carolina, 84

Rosellinia mammaeformis, 508; subiculata,
508

Rozites gongylophora, 222

Rubus hispidus, 81; saxatilis, 170

Rudbeckia, 163

Rudbeckia hirta, Inheritable variations in
the yellow daisy, 89

RypBeErG, P. A. Vegetative life zones of
the Rocky Mountain region, 477

Sabal, 510, 569; Blackburnianum, 506, 509

Sabbatia stellaris, 86

Sabina occidentalis, 493; monosperma,
478, 487, 493; scopulorum, 478, 483,
485, 486, 488; utahensis, 478, 487

Saccharum officinarum, 510

Saccobolus Kerverni, 506

Salicornia ambigua, 571;
perennis, 571

Salix, 478, 483, 488; herbacea, 170

Salvia Peice cdon. 201; mellifera, 200;
micrantha, 577; serotina, 577; Sessei,
201; spathacea, 200

Sambucus, 481; canadensis, 81

Sanguisorba canadensis, 86

Sanicula, 192, 193; marilandica, 194

Saprolegnia, 256

Sarcobatus, 494

Sarcomphalus domingensis, 575

Sarcoscypha minuscula, 503, 506

Sargassum vulgare, 118

Sarracenia, 163, 307

Sassafras, 80, 163

Saxifraga oppositifolia, 168; stellaris, 172

Scaevola Lobelia, 567; Plumieri, 567, 578

Schizandra chinensis, 29, 31

Schizoneura Carrerei, 77

Schizophyllum alneus, 511

Schoepfia obovata, 570

Scleropogon brevifolius, 490

Sclerotium, 553; bataticola, 553; durum,
5543 Semen, 509

SEAVER, FRED J. Bermuda fungi, 501

Secale, 346, 422; cereale, 346; montanum,
346

europaea, 85;

INDEX

Sedum roseum, 168
Segregation of genera in Lentibulariaceae,

Self- and cross-pollinations in Cichorium
Intybus with reference to sterility, 333

Self, close and cross fertilization of beets,
149

Senecio atriapiculatus, 207; crassulus,
207; cruentus, 339, 340; dispar, 207;
hydrophilus, 207; hydrophilus pacificus,
207; integerrimus, 207; lugens, 207;
taraxacoides, 207; triangularis, 207

Septoria oleandrina, 509

Sericocarpus, 163

Serjania polyphylla, 575

Setiscapella, 42, 57, 64; subulata, 57, 58

Sex-ratios in Mercurialis annua, Obser-
vations on inheritance of, 69

SHAW, Harry B. Self, close and cross
fertilization of beets, 149

Sida ciliaris, 575

Silene acaulis, 168, 170

Silphium, 163

Silver scurf (Spondylocladium atrovirens
Harz) of the white potato, A contri-
bution to our knowledge of, 549

SINNOTT, EDMUND W. Endemism as a
criterion of antiquity among plants, I61

Sisyrinchium, 271, 305; linifolium, 188

SMALL, JOHN K. Recent exploration in
southern Florida, 475

Smilax glauca, 84; rotundifolia, 81

Soil fertility, Plantecology and the new, 319

Solanum persicifolium, 578; tuberosum,
599, 554 i

Solidago, 163, 463; sempervirens, 85, 86;
Virgaurea, 169

Somatic and reduction divisions in certain
species of Drosera, 125

Some things learned in managing a botanic
garden, 513

Sonora, Mexico, including a Neocalamites
not previously reported from North
America, Triassic plants from, 75

Sophera tomentosa, 573

Sorbus, 252; alnifolia, 252; Aria, 252

Southern Florida, Recent exploration in,
475

Spartina cynosuroides, 85; patens, 85, 86

Spathyema foetida, 81

Species of Allodus, North American, 173

Species of Drosera, Somatic and reduction
divisions in certain, 125

Species of Gymnosporangium, Japanese,
245

Spermacoce tenuior, 578

Sphacelaria, 259, 260, 264

Sphaerostilbe flammea, 507

Spirogyra, 103, 109, 258-260, 269, 277

Spondylocladium atrovirens, 549-552,

55 0

(Spondylocladium atrovirens Harz) of the
white potato, A contribution to our
knowledge of silver scurf, 549

Sporobolus angustus, 509; argutus, 568;
virginicus, 568

Sporormia intermedia, 508; minima, 508

Sporotrichum densum, 68; flavissimum, 68

Stanleya, 163

Status of the problem of the effect of
radium rays on plant life, Present, 153

Staysanus Stemonitis fimetarius, 509

Stereum hirsutum, 511; radians, 511

Sterility, Self, and cross-pollinations in
Cichorium Intybus with reference to, 333

Stictis graminum, 506; radiata, 506

Stigmaphyllon lingulatum, 573

Stilbocrea hypocreoides, 507

Stipa, 181; eminens, 181

Stomoisia, 44, 52, 55, 64; cornuta, 54, 55

Stout, A. B. Self- and cross-pollinations
in Cichorium Intybus with reference to
sterility, 333

Streblonema, 108; solitarium, 106, 108-
I1O, I12, 115, 118

Streptotheca, 503

- Stropharia ambigua, 221

Strumpfia maritima, 578

Stylosanthes hamata, 573

Suriana maritima, 567, 573

Swamp at Merrick, Long Island and its
significance, A white-cedar, 79

Swertia, 195; palustris, 195; perennis,
195; scopulina, 195

Swietenia Mahagoni, 29, 31

Symphoricarpos, 163, 481, 487; occiden-
talis, 485, 490

Symplocarpus, 272, 305

Synchytrium, 261

Syringa, 137, 279, 280, 306, 307; persica,
127; rothomagensis, 127; vulgaris, 127

Tabebuia heterophylla, 567, 578

Tanacetum, 282

Taonia atomaria, 108

Taraxacum, 281, 282, 306, 363

TAUBENHAUS, J. J. A contribution to
our knowledge of silver scurf (Spondy-
locladium atrovirens Harz), of the

’ white potato, 549

Taxus brevifolia, 483

TayLor, NoRMAN. A white-cedar swamp
at Merrick, Long Island, and _ its
significance, 79

Temnoceras, 46, 47

Tetracentron, 27-31; sinense, 29, 31, 32

Tetracentron, Trochodendron and Drimys
specialized or primitive types? Are, 27

Tetracotyledonous race of Phaseolus vul-

Tetradymia, 488, 494
garis, A, 229

Tetralobus, 49

Tetramicra elegans, 570

Tetraploa aristata, 509

Tetraspora, 258

Thalictrum alpinum, 169

Thecotheus Pelletieri, 506

Thelypodium, 163

592 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

THompson, W. GILMAN. Address of
WwW elcome, I

THompson, W. P., and I. W. Bailey. Are
Tetracentron, Trochodendron and
Drimys specialized or primitive types? 27

Thrinax Morrisii, 569

Thuya plicata, 483; occidentalis, 481

Tillandsia utriculata, 569

Tissa marina, 85

Tithymalopsis, 455; arundelana, 455-458;
corollata, 455, 457, 458; Ipecacuanhae,
455-457; marylandica, 455, 457; zin-
niiflora, 457, 458

Tithymalopsis, Variation in, 455

Torenia, 562

Townsendia, 163

Toxicodendron radicans, 81; Rydbergii,
490; Vernjx, 81

Tradescantia, 263, 271, 281, 305

Tranzschelia punctata, 510

Tremella koreaensis, 249

Triadenum virginicum, 81

Triassic plants from Sonora, Mexico,
including a Neocalamites not previously
reported from North America, 75

Trichoglossum hirsutum, 502, 505; hir-
sutum Wrightii, 502, 505

Trichomanes, 170

Trientalis americana, 81

Trifolium, 515; pratense, 338

Trillium, 272, 305

Trilobulina, 60

Trip to North Wales in June, A botanical,
167

Trixapias, 54

Trochodendron, 27, 29-31; aralioides, 29,
31, 32

Trochodendron, and Drimys specialized
or primitive types? Are Tetracentron, 27

Trollius europaeus, 169

Tropaeolum, 275, 281, 285, 302, 303,
306-308; majus, 275, 284; minus, 275

Troximon, 162

Trutta, 262

Tsuga heterophylla, 481, 483

Types in Pediastrum, On the nature of, 91

Tyromyces graminicola, 511

Udotea cyathiformis, 105

Ulmus americana, 485, 489

Ulothrix, 259

Ulva, 567

Umbellularia, 163

Unifolium canadense, 81

Urechites lutea, 576

Uredo nootkatensis, 251

Uromyces Behenis, 177; Glycyrrhizae,
176; Scrophulariae, 177

Uromycopsis, 173, 175, 177, 178

Ustilago Carbo, 504; Zeae, 504, 509

Utricularia, 39-41, 43, 50, 52, 54, 56,
59-62, 64, 538; alpina, 53; bryophila,

543 caerulea, 50-52; capensis, 56;

cornuta, 54; cucullata, 63; denticulata,
56; dichotoma, 53; fimbriata, 49;

Glaziuana, 57; hydrocarpa, 61; inflata,
61; macrorhiza, 59, 60; Mannii, 54;
minima, 59; minor, 39, 60; minutissima,
52; multifida, 49; mneottioides, 56;
olivacea, 59; parviflora, 52; pumila, 60;
purpurea, 62; racemosa, 51; resupinata,
58; reticulata, 52; saccata, 62; Spru-
ceana, 58; striatula, 50; subulata, 58;
tubulata, 63; vulgaris, 39, 61

Vaccinium, 84, 481; atlanticum, 81;
atrococcum, 81; Myrtillus, 170

Vagnera racemosa, 81

Valeriana acutiloba, 204; edulis, 204;
occidentalis, 204; officinalis, 204; sit-
chensis, 204

Valerianaceae, 204

Variation in Tithymalopsis, 455

Variations in the yellow daisy (Rudbeckia
hirta), Inheritable, 89

Varronia bahamensis, 577

Vegetation of Anegada, The, 565

Vegetative life zones of the Rocky Moun-
tain region, 477

Velaea arguta, 192; Hartwegii, 192

Venus mercenaria, 86

Vermicularia, 553-556; atramentaria, 553,
554, 558; atramentaria sclerotioides, 553

Vesiculina, 42, 44, 61-64; cucullata, 61,
63; purpurea, 62

Viburnum dentatum, 81

Vicia, 254, 283, 306

Vicinity of Beaufort, North Carolina,
Notes on some marine algae from the,

105

Viola lobata, 174, 188; ocellata, 174, 188;
pallens, 81; papilionacea, 81; praemorsa,
188

Vitis, 335; aestivalis, 81

Volkameria aculeata, 577

Walchia, 78

Wedelia parviflora, 579

Welwitschia, 27

White-cedar swamp at Merrick, Long
Island, and its significance, A, 79

Woodwardia areolata, 81; virginica, 81

Xananthes, 60
Xenoxylon latiporosum, 30
Xylaria arbuscula, 509; filiformis, 508

YAMPOLSKY, CECIL. Observations on in-
heritance of sex-ratios in Mercurialis
annua, 69

Yellow daisy (Rudbeckia hirta), In-
heritable variations in the, 89

Yucca, 493, 494; glauca, 491

Zamia, 268, 305

Zamites (Otozamites?), 77; Powellii, 77

Zasmidium cellare, 68

Zea, 305; Mays, 273, 509

Zizia, 163

Zones of the Rocky Mountain region
Vegetative life, 477

Zostera, 110

Zygogynum, 27

'
————— ss eT

ee * :

Bye ST)

ie er eperh y AS
. ee

lage
, x

via a at Ms

, . , ns co.

7 i ; y : das bay :
ia ke T- ne is

-
x
‘
—
oe: a < —
ae al .

aa
¥
~~

{
= Pr

‘~ -

”
- Y ‘ *
! a 1f> AH
a I es
f } or)
1 Me
‘ ; vo re
f a. (*
* 7 i fal uae
7 ? }
- de 7 ‘i wf 4 \a
i et r
; . rel hl
« era ou
ve . if ‘
. OL dinky!
¥ g str e >\ ¥
VA y a
ae
f Vi,
ad A , @
at
ae
- 7 At:
"
A :
5 ss
’ aay
7a
Ai
j -
A ’
—
‘
*
i
.

ae Ove, |) ;
BiG ae)

lew York Botanical Garden Librai

‘unm

3 5185 00099 a

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Papers presented at the Celebration of the Twentieth Anniversary of the New York Botanical Garden, September 6-9, 1915. Published by the aid of the David Lydig Fund, bequethed by Charles P. Daly"

See other formats