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THE BOTANICAL GAZETTE

THE UNIVERSITY OF CHICAGO PRESS
CHICAGO, ILLINOIS

THE wegen: ah a kere brambles PRESS

THE psndiougnie es
TOKYO, OSAKA, KYOTO, FUKUOKA, SENDAI

THE MISSION BOOK COMPANY
SHANGHAI

Qi]
THES © 1 Ougs

ree
BOTANICAL GAZETTE

EDITOR
JOHN MERLE COULTER

VOLUME LXxXIl
JULY-DECEMBER 1921

WITH SIXTEEN PLATES AND-NINETY-TWO FIGURES

THE UNIVERSITY OF CHICAGO PRESS ar
CHICAGO, ILLINOIS ZA\\R

Pu ed
July, August, September, October, November, December, 1921

Com sed and Printed By
The Vaiverday of Chicago Press
Chicago, Illinois, U.S.A

TABLE OF CONTENTS

Respiration of dormant seeds. Contributions ssi
the Hull Botanical oe 282 eats

Bente + oss aes Se wha Hope Sherman
‘Leaves of the Helobieae (with plateI) - - - - Agnes Arber
Notes on new or rare species of rusts - - - -. W. H. Long
Peat deposits and their evidence of climatic —.

(with twelve figures)- - - oo ae A. P. Dachnowski
Life history of Corallina officinalis var. mediterranea S. Yamanouchi
Intra-ovarial fruits in Carica Papaya (with six

figures) - Bi ed ee ee H. F. Bergman .
Leaves of certain Amaryllids (with eight figures) - Agnes Arber
A homosporous American Lepidostrobus. Contri-

butions from the Hull Botanical roseanad

283 - eae ea ea a - John M. Coulter and

W.J.G. Land

Effect of direct current on cells of root tip of Canada

field pea (with plates II, III, and three figures) Henry F. A. Meier
Chemistry of after-ripening, germination, and seed-

ling development of juniper seeds. Contribu-

tions from the Hull Botanical Laboratory 284 Dean A. Pack
Leaf-tissue production and water content in a
mutant race of Phaseolus wilgaris - - - - J. Arthur Harris

Technique in contrasting mucors (with two figures) Albert F. Blakeslee,
Donald

ch, and
Ki Yue Cartledge

Germination of aeciospores, eee | and

teliospores of Puccinia coronata- - - . G. R. Hoerner
Sexual dimorphism in Cunninghamella (with one
figure) « = 4 « <> = = = =.» = +> Albert F. Blakesiec,

J. Lincoln Cartledge,
and Donald S. Welch

Notes on willows of sections Pentandrae and oer
(with four figures) - - - - Carleton R. Baill

PAGE

vi CONTENTS [VOLUME LXxII

Polypodium vulgare as an epiphyte (with three
figures)- - - = - = = = = = = Duncan S. Johnson

Chromosomes of Sse at conicum (with

plates IV, V)- - - - - = = Amos M. Showalter
Peach yellows and little peach (with plates VI, VII) Mel. T. Cook
Effect of location of seed upon germination- - — Edward N. Munns
Decay of Brazil nuts Silo Lorne VITI-XIT and

three figures) - - - - - - Edwin Rollin Spencer

Growth rings in a monocotyl. Contributions from
' the Hull Botanical ye 285 Ae six-
teen figures) - - - - C.J. Chamberlain

Invasion of virgin soil in the tropics (with two
figures)- - - - - = = - = = - - Duncan S. Johnson

Pectic material in root hairs. Contributions from
the Hull Botanical Laboratory 286 - - - Caroline G. Howe

Destruction of mosses by lichens. Contributions
from the Hull Botanical y sutaliais 287 sie
plate XIII) - - - ee - Frank P. McWhorter

Annual rings of apene: in carboniferous wood (with
plate XIV) - - - - - - - Winifred Goldring

Optimum temperatures for flower seed germination
(with ten figures)- - - - - - - - = Geo. T. Harrington

Reaoeuinan organs of bog plants. Contributions
m the Hull Botanical —— 288 aa

cian figures) - - - - Se Fred W. Emerson
Morphological study of Carya alba and Juglans

nigra (with plates XV, XVI, and one figure) - Theo. Holm
Phylogenetic position of the bacteria - Hilda Hempl Heller
Odontopteris genuina in Rhode Island with ‘Eve

figures) - - Eda M. Round
BRIEFER ARTICLES—
Helmut Bruchmann (with portrait) - - C. J. Chamberlain
Root caistaareaies of wheat ein ane” vith one

figure - W. F. Gericke

PAGE

VOLUME LXxu] CONTENTS vii

- 48, 109, 178, 261, 331, oe

CURRENT Lireniroek - - -
For titles of book reviews see index under
author’s name and reviews
Papers noticed in “Notes for Students” are
indexed under author’s name and subjects

DATES OF PUBLICATION
No. 1, July 16; No. 2, August 15; No. 3, September 15; No. 4, October 15;
No. 5, November 15; No. 6, December 15.

ERRATA
Vor. LXXI
P. 422, line 14, for microchemical read macrochemical
Vor. LXXII

P. 305, footnote, for no. 70 read no. 71
P. 314, line 7 from bottom, also in headings of tables I and III, for ruthenian

read ruthenium
P. 318, table II under radish test for callose in sand, for Layer at tip read

Same as in loam

VOLUME LXXII NUMBER 1

fee ie
BOT wc aY CNeTTE
JULY to2t

RESPIRATION OF DORMANT SEEDS

CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 282
Hope SHERMAN
(WITH FOUR FIGURES)
Introduction

Plant physiologists have long been interested in the physio-
logical processes associated with the development and particularly
with the germination of seeds. Much attention has been devoted
to those seeds which, when ripe, fail to respond to germinating
conditions unless subjected to special treatment or permitted to
undergo a distinct rest period. Such dormant seeds offer many
problems to pique the curiosity of the investigator, and work on
individual seeds has given some conception of the environmental
factors influencing dormancy (4, 15, 17, 40), as well as of the internal
conditions retarding germination and of the chemical changes
which take place in after-ripening (19, 25, 27,38). Furthermore,
dormant seeds often retain their viability for long periods of time.
BEALE (7, 8, 24, 41) reported that Amaranthus retroflexus will remain
viable in the ground for thirty years. If such seeds are fully
imbibed, their remarkably prolonged viability may be due either
to especially large food reserves or to a tremendous reduction of
the rate at which such reserves are respired. A study of the
respiration of stored seeds at different time intervals might help
to interpret this point.

2 BOTANICAL GAZETTE (yuLy

While the respiration of most plant parts has been studied
more or less, there are comparatively few data on resting seeds.
For this reason the study of the respiration of seeds would be of
interest, per se, and if dormant seeds were selected, it might be
possible both to discover differences in the respiration of related
and of unrelated species, and, through the acquisition of informa-
tion upon the rapidity with which food reserves were utilized, to
arrive at some idea of the probable longevity of the seeds.

Most dormant seeds belong to one or another of certain main
classes (CROCKER 14): those in which the dormancy is due to
coat characters, as impermeability to water or to oxygen, acting
in conjunction with some physiological character in the embryo
aside from actual dormancy; or those in which dormancy is con-
ditioned by the embryo itself, either through lack of differentia-
tion or through the absence of some factor essential for germination,
even when the naked embryo is exposed to all ordinary external
germination conditions. In addition there are certain seeds with
mature embryos whose coats apparently exclude neither water nor
oxygen, but still germination is hindered; such delay in Alisma Plan-
tago (15) is due to the inability of the embryo to overcome the
mechanical resistance to expansion offered by the coats. Finally,
dormancy may result from the joint action of two or more of these
factors.

In the investigation, some of the results of which are embodied
in this paper, the original intention was to study the respiration of
each type of dormant seeds, but during the progress of the work
the comparative respiration of dormant seeds has become of prime
interest, and this phase forms the subject of the present report.

The seeds selected were three on which physiological studies
had already been made, but for which respiratory data were lack-
ing, namely, Amaranthus retroflecus, Chenopodium album, and
Crataegus,* and in addition (because of their economic importance
and the ease with which they could be obtained, as well as because
of their relationship to Crataegus) seeds of the common drupaceous
Rosaceae. In Crataegus and Amaranthus some attempt has been
made to determine variations in respiration accompanying after-

* The species chiefly studied was C. coccinea.

1921] SHERMAN—DORMANT SEEDS 3

ripening or aging. Furthermore, since many workers claim that
catalase activity varies with the respiration, catalase determina-
tions have been made on most of the seeds used.

Methods
Catalase activity was measured by the volume of oxygen set
free from hydrogen peroxide (the Oakland Chemical Company’s
dioxogen) by a given weight of seeds. The apparatus was essen-
tially that described by APPLEMAN (1), and the routine procedure
was to grind the seeds for one minute in a mortar with sand and
calcium: carbonate, add 5 cc. of distilled water, and grind a second
minute. The contents of the mortar were then transferred to a
bottle which was placed in a water bath at 25°C. The level of the
gas burette was adjusted, and after sufficient time had elapsed for
the seed suspension to come to the temperature of the bath, the
exit of the gas burette was closed. Constancy of level of the water
meniscus in the gas burette was assumed to indicate stability of
temperature. Thereupon the cock of the dropping funnel was
opened on the minute, and 5 cc. of dioxogen was allowed to flow
into the bottle, which was immediately set shaking. Readings of
the volume of oxygen liberated were taken on the gas burette every
minute for the first five minutes and on the tenth minute also.
The respiration determinations were made by means of a respi-
rometer designed by CRocKER (26). This consists of a cylin-
drical glass chamber fitted with a glass stopper through which
pass two tubes, one a manometer and the other a short, straight
tube provided with a stopcock by which the chamber can
be closed to the surrounding air. Seeds which had been soaked
for twenty-four hours and thereafter stored on moist filter paper
at about 10° C. were placed in a porcelain hooded holder, designed:
by Harrincton (25). This holder was supported within the

respirometer on projections from its wall about 1 cm. above the
se. The respirometer was placed in a water bath at constant
temperature, and after half an hour the mercury in the manometer
was brought to a level and the stopcock closed. When the experi-
ment was to be brought to an end, the difference between the
mercury levels in the two arms of the manometer was measured,
and a known volume of caustic potash was introduced into the

4 BOTANICAL GAZETTE [ony

respirometer through the stopcock tube. The potassium hydroxide
was allowed to flow down the sides of the respirometer, the hood
of the seed holder preventing its coming into contact with the seeds.
So far as possible, measurements were made and absorption carried
out without removing the respirometer from the bath. A second
reading of the manometer was taken after absorption of the carbon
dioxide. Barometer readings were taken after closing the chamber
at the beginning, and again before absorption of the carbon dioxide
at the end of the experiment. From the calibration of the respi-
rometer it was possible to calculate its volume at the beginning (cor-
rected for the volume occupied by the seeds) and at the end, before
and after carbon dioxide absorption, a correction for the volume
of the absorbent added being applied in the latter case. All
volumes were further corrected to absolute zero, and to 760 mm.
pressure. The difference between the volumes at the end of the
experiment before and after carbon dioxide absorption represents
the volume of carbon dioxide eliminated by the seeds, while the
difference between the volume at the beginning of the experiment
and that after absorption represents the volume of oxygen taken
up by the seeds. These relations are expressed by the following
formulae, which were used for the calculation:
et V,=volume of respirometer,

V,=volume of imbibed seeds,

V,=volume of absorbent (KOH) used,

T,=initial absolute temperature,

T,=final absolute temperature

B,=initial barometric pressure,

B,=final barometric pressure,

m,=initial manometer reading,

m,=final manometer reading.

A: V,— Rx tas
(V,-V)23x Be
B: (V,—V.)BS xs
760 —

C: V.-V.-V 2B RE
( aX ce

1921]

Then

SHERMAN—DORMANT SEEDS

B—C=volume of CO, eliminated,
A—C=volume of O, absorbed.

From these volumes the respiratory quotient (CO,/O,) is easily cal-
culated, as are also the milligrams of carbon dioxide eliminated
and of oxygen absorbed per gram of imbibed weight per day,
using 1.96 mg. as the weight of 1 cc. of CO., and 1.428 mg. as

that of 1 cc. of O,.?

? The application of these dae bia is illustrated i in the following calculation of
data from an experiment on Amaranthus

Vr=24.61 cc T,=25° C. By,=751.5 mm. =— gmm.
Vs= 1.00cc T.™ 25° C. B.=749.8 mm. m,= —65 mm.
Va= 0.76 cc.
Weight imbibed seeds=1.3177 gm.; duration of experiment= 24 hours.
24.61
— 1.00
23.61X OE 8 SB 21.387 (A)
298
23. orx 8.273 _ =21.082 (B)
298
— 0.76
22. 22.85x S85 x 273-38. 862 (C)
298
Log. box 98 7 7-081133—10
log. 23.61=1.373006 log. 23.61=1.373096 log. 22.85=1.358886
log. 751.5 =2.875929 log. 740.8 =2.869701 log. 684.8 =2.835564
— 3.081133 —3.081133 —3.08113£
1.330158 1.323930 1.275583

Antilog. 1.330158= 21.

387 Antilog. 1.323930=21.082 Antilog. 1.275583=18.862

B~C=21.082~18.862=2.220cc. CO,; A—C=21.387—18.862=2.525 cc. 0,;

CO,/0,=0.88 880
log. 2.220 =0.346353 log. 2.525 =0.402261
1.96 =0.292256 log. 1.428 =0.154728

log
wea zr. 3177 =0.880183 880183
b exeres

colog. 1.3177 =0.880183
0.437172

antilog. 0.518792 =3.302 mg. CO, per gm. imbibed weight per 24 hours.
antilog. 0.437172=2.736 mg. O, per gm. imbibed weight per 24 hours.

6 BOTANICAL GAZETTE [JULY

Investigation
The material studied was as follows:
Seeds ar of crop Time of collection
Amaranthus retroflexus 1919 August 2-September 7, 1919
Chenopodium album 1918 January 29, 1919
Rumex crispus 1919 ©63—Ss-—s August 1919
Crataegus IQI7 October 1917

In addition, seeds of Prunus pumila (from Mineral Springs, Indiana),
and of P. persica, P. armeniaca, P. Cerasus var. Morella, P. do-
mestica var. Blue Gage, and the red Burbank plum, obtained in the
market, were also studied. All rosaceous seeds except Crataegus
were freed at once from pulp, dried, and in most cases opened and
used immediately. Amaranthus and Chenopodium seeds were
stored at room temperature until used. Seeds of Crataegus were left
at room temperature until they were scanint from the carpels,
when they were placed at once under g ditions at 10°C.
In preparation for an experiment the seeds were pce in
distilled water and left in the refrigerator at approximately 10° C.
for twenty-four hours. Cotton and filter paper were placed in
Petri dishes and the whole sterilized in an electric oven. Before
being used, the cotton was saturated with sterile distilled water.
The seeds were thoroughly shaken in several portions of sterile
water, and were either used at once or placed in the Petri dishes
and stored in the refrigerator until needed, in order to avoid the
influence on respiration of variations of temperature. By means
of these precautions it was possible, to a very great extent, to pre-
vent infection of the seeds with molds or bacteria, and at the same
time to avoid the modification of respiration due to treatment with
disinfectants (36, 38, 42). The amount of material used depended
largely upon the size of the seed and of the apparatus. For
Amaranthus and Chenopodium, 1 gm. of air-dry seeds was the usual
amount, a weight representing approximately tooo seeds. Cor-
responding numbers and weights for the other seeds were:

Seed Number | Weight (gm.)
MU CON 0.5
us i 2 0.7 1.00
Prunus domestica 2 0.7 -0.8
us armeniaca I 0.8+
Prunus Cerasus 10 0.8
Prunus pumila I 0.8

1921] SHERMAN—DORMANT SEEDS 7

With the use of large numbers of seeds, possible in the case of the
small seeds of Amaranthus, Chenopodium, and Rumex, individual
variations are abolished, and the results are probably more nearly
typical than those obtained by the use of one or two seeds, where
individual peculiarities would assume an exaggerated significance.
From four to ten lots of seeds were run at the same time, since the
variability in oxygen consumption and in carbon dioxide elimina-
tion was early evident, and it was only by running at least four
experiments simultaneously, under precisely similar conditions,
that variability could be limited to factors intrinsic in the seed.

The experimental temperature (with rare exceptions) was either
20° C. or 25° C., and the results are all corrected to a comparable
basis. The average duration of the experiments was 24 hours.
Occasionally a longer time interval was employed, but rarely a
shorter, as the amounts of gas absorbed and eliminated were
usually small. The average amount of carbon dioxide eliminated
during an experiment was 2cc., with a maximum of 4cc. The
volume of the respirometers was approximately 25 cc. Since
Kipp (28) found that ro per cent of carbon dioxide retards respira-
tion, the accumulation of this gas during an experiment may have
slightly modified at times the character of the respiration.

CATALASE DETERMINATION

Table I is a comparison of the catalase activity in the different

seeds studied. The variability in catalase activity is extreme,

TABLE I
CATALASE ACTIVITY OF SEED IMMEDIATELY AFTER HARVESTING

OxycEN (cc.) LIBERATED AFTER
WEIGHT OF
SEEDS MATERIAL ConpITIoN
(cm.) a oo 8 a)

| minute |minutes|minutes/ minutes
Amaranthus ie bosrigag 0.13 Imbibed 3.20 | 6.10 | 7.67 | 8.97
Lo um...| 0.13 Imbibed 3.00 | 6.05 | 7.40 30
AMO 0.13 Imbibed 10.10 135.10 |48.20 |56.50
Blue sae pain. 2. 0.13 Imbibed 7.90 |21.40 |28.80 |35.60

Blue gage plum. ...... 0.13 As removed from
carpe 2.65 | 9.93 |12.68 |16.55

Burbank plum........ 0.13 As removed from
carpe 2.12 | 7.85 | 9.72 |x1.70

Crate 0.0449 | As removed from
carpel 4.50 |10.50 |14.30 |18.30
Crataemus. . 0.0688 Imbibed 7.50 |18.00 |23.10 |27.60

8 BOTANICAL GAZETTE [JULY

especially among the rosaceous seeds. Of these, the greatest
activity occurred in apricot, 48 cc. of oxygen being liberated from
hydrogen peroxide in five minutes by 0.13 gm. of imbibed seeds.
The red Burbank plum had the lowest activity of any rosaceous
seed, an equal weight of imbibed seeds liberating only 9.7 cc. of
oxygen. In table II the catalase activity of hawthorn is given by
periods from the fourth to the forty-second day, while the same

—
iJ

ers

Fic. 1.—Curves of catalase activity at 1, 3, 5, and ro minute intervals in a
horizontal axes represent time in days after harvesting; vertical axes represent cc
of O, liberated; temperature 25° C.

data are presented graphically in fig. 1. There is an increase in
catalase activity as after-ripening progresses. A determination
made on the after-ripened seeds, 128 days at 10° C., suggests that
this increase continues after the forty-second day, but at a very
slow rate. This slowness of increase was observed by ECKERSON
(t9) in her microchemical study of after-ripening in Crataegus.
The stability of catalase activity in Amaranthus during the first
month after harvesting is plain from table III.

SHERMAN—DORMANT SEEDS 9

1921]
TABLE II
CATALASE ACTIVITY IN Crataegus DURING DORMANCY
Numeer oF Weicut oF OXYGEN (CC.) LIBERATED AFTER
DAYS MATERIAL
ag Hah (cm.) I minute 3 minutes 5 minutes Io minutes
a Aa rae 0.0410 es! 3.7 17.9 22.9
Oia 0.0690 4-4 10.6 14.3 18.8
Bees eb a oe 0.0778 og 15:0 20.0 26.2
Oe ec cere 0.0773 II.9 ayo2 36.0 45.5
7 Ree ne be 0.0791 E763 42.9 57.0 65.8
So} ena ap ie ©.1007 25.6 57.2 65.2" 67.0

*There are two — explanations for small in talase activity from the 42nd to
the 128th day: (1) the amount of oxygen liberated may yon Dek limited by the use of wae: 5 cc. of
dioxogen; (2) adetermination should have ened coo at 2 Asad when after-ripening was complete.

ndary dormancy

After that time the seed may go into a seco!

TABLE III

CATALASE ACTIVITY IN Amaranthus retroflexus (0.13 GM. IMBIBED SEEDS USED)

UMBER OF OXYGEN (CC.) LIBERATED AFTER
DAYS AFTER
eke cima I minute 3 minutes 5 minutes ro minutes
Brinn tae 3.0 6.2 7-9 9.2
ROD aay ea a 2.3 5.0 6.2 7.3
Oi aes 3-4 6.2 7-7 9.9
EA eRe ee een 3:8 73 8.9 10.4
RESPIRATION

Table IV embodies the comparative respiratory behavior of
all ten seeds. While all but Rumex have a respiratory quotient
less than unity, indicating an oxygen intake in excess of the carbon
dioxide elimination, the value of the carbon dioxide-oxygen ratio
varies within wide limits. For the Rosaceae the “respiratory
intensity,” as measured by the milligrams of carbon dioxide
eliminated per hour per gram of imbibed seeds, averages about
0.08, while in the other seeds it is higher, being about o.11 in
Amaranthus, and 0.15+ in Rumex and Chenopodium. This ditfer-
ence may be due to the character of the storage substance, chiefly
starch (44), present in the last three seeds, but it is undoubtedly
also attributable in part to a difference in degree of dormancy.

Io BOTANICAL GAZETTE [JULY

Only one set of experiments was carried out on Rumex, because
it was found that even immediately after harvesting the seeds
would germinate. In many of the seeds the coats were ruptured
and the hypocotyls emerging by the end of the experiment. Cheno-
podium also exhibited a marked readiness to germinate. Amaran-
thus was more dormant, but even within a few weeks of harvesting,
on removing the seeds from the respirometer after an experiment,
an occasional seed with coat broken was found; while during the
later experiments, over 100 days after harvesting, the number
“with broken coats increased greatly (80 seeds per 1000). The

TABLE IV
RESPIRATORY VALUES (AT 25° C.)
Mg. Mg. O: per
No. of
Sanit exits | COVO» eben et tn urs tem.

Amaranthus retroflexus. . ay 0.856 2.691 2.324
Che di ry ea! 14 0.928 4.213 3.307
umes crise. | 9 1.160 3.636 2.201
Cra "BIN Weegee lis Sir 56 0.774 1.548 1.474
Siinecay eee owes 14 0.675 1.881 2.033

As wie eee ea eee 30 0.648 2.106 2.392
Cer te heer. 19 0.866 2.589 2.186
Senda Cnn 3 ge eee Daan ai al 19 0.876 2.288 T.935
Blue gage plum........... 19 0.6096 2.579 2.748
Burbank plum............ 10 0.912 1.998 1.610

rosaceous seeds are really dormant. Crataegus requires three
months of after-ripening at low temperature (5° C. optimum) before
the hypocotyl emerges from the coat. The changes occurring dur-
ing after-ripening in Crataegus progress slowly (19) until very near
the end of dormancy. The data reported represent determinations
covering the period from the first to the seventy-seventh day under
germinating conditions. At this latter time the seeds are still
dormant and would fail to germinate if removed to a higher tem-
perature. For the other rosaceous seeds no attempt was made to
determine the exact duration of dormancy, although it was observed
that seeds left in the refrigerator germinated in from 1.5 to 3
months.

It has been suggested (17) that the dormancy of Crataegus,
although chiefly conditioned by the embryo, is in part dependent

1921] SHERMAN—DORMANT SEEDS 1*

upon the coats, which reduce the rate of imbibition and perhaps
of oxygen entrance. The effect of an atmosphere entirely oxygen
was accordingly determined, and it was found that the quotient
and the respiratory intensity of the dormant seed still fluctuated.
The mean respiratory quotient was a trifle lower than in ordinary
air, 0.728 instead of 0.774. Further investigation of this point
will determine the effect of varying percentages of oxygen upon the
dormant seed and on the after-ripened as well. Although a de-
tailed study of the respiration of the after-ripened seed is yet to
be made, data already obtained seem to indicate that the respira-
tory quotient and the milligrams of carbon dioxide eliminated are

TABLE V

RESPIRATION OF Amaranthus retroflexus (AT 25° C.)*

Mg. O; pe
i r hou

Number of days after harvesting CO:/O2 hours cole “4 bel pet am.

Bice es Sounkyo 0.824 2.425 2.150
SOON ie ae ay een ren RG rs 0.850 2.263 1.938
A ea ee ' 9.892 2.299 1.877
Be pny oe ee ai 0.890 2.932 2.417
eS ES IR Ee E 0.854 1.955 1.656
LGR SS a alates SMe SOM ir a pre 0.877 2.705 2.501
WO oe ee 0.802 4.475 4.056
bP Ba era en are gr gases a mene 0.885 3-979 3-500
RPG oc hee ale ee 0.842 1.79 1.537

* Seeds stored at room temperature until used.

slightly higher than in the dormant seed, while the oxygen absorp-
tion is lower. The effect of increased percentages of oxygen on
after-ripened apple seed is to increase its respiratory intensity (25).
It may be that this will be found to be the effect on the after-
ripened hawthorn.

The values given for Amaranthus in table IV are averages
based on experiments on seeds at intervals from 3 to 176 days after
harvesting. In table V these respiratory values are given by
periods, while in fig. 2 the carbon dioxide-oxygen ratio, and the
respiratory intensity, as indicated by milligrams of carbon dioxide
eliminated as well as of oxygen absorbed, are plotted in a time curve.
The uniformity of the carbon dioxide-oxygen ratio is noticeable.
The high values for the 104th and 140th days are accompanied by

12 BOTANICAL GAZETTE [JULY

a slight increase in germination. Still more interesting facts are
brought out by the frequency histograms (fig. 3), from which are
evident the value most frequently appearing for the carbon dioxide-
oxygen ratio, and the total variation of this ratio in the entire
number of experiments on each seed. In plotting these histograms
the values for the quotients were grouped, and since it was found
that experimentally and mathematically the digits for the quotient

45.
=
"| ie
20.
mg O2
bb
ow CO, /o2
os 4
ee ee eee es ie

A th 3

R
horizontal axes represent time in days after harvesting: vertical axes represent values
from 0.5 to 4.5 for the CO,/O,, these being absolute numbers indicating ratio; for
“respiratory intensity” curves represent mg. of gas per gram imbibed weight of
seeds per 24 hours.

are significant only to hundredths, the interval between these
groups or classes was taken as 0.01.

The range of the value of this ratio, as determined by the
maximum and minimum, varies widely in the different seeds, being
least in Amaranthus (0 .685-0.975, that is, 29 classes) and widest in
hawthorn (0.470-1.140, that is, 67 classes). In Chenopodium
the heaviest grouping lies within a range of only seven classes, but
between the lower limit of this group and the next lowest quotient
is a gap of nineteen classes, while above the group’s highest limit

SHERMAN—DORMANT SEEDS

1921]

‘vo'o UONVIANP piepuys zo’o UOVIADp uvaut {1£'6'0 uvaut {(S69°0-Sg9"0)
10°O mntpogouayy IOJ [BAIT SST *SO°O UOT}BIADp prepurys {hoo uONeIADp uvaut {g/Sg°o uvour § ($69°0-$g9°0) 10°0
SnyjuDsvMy OY [BAIOUL sse[Q ‘*zL1°O UOTeIAGp prepurys fgo’o Aq 64°0 wos Alva 0} pua} [LM syuswedxa yons
jo Aytuofeur souey ‘6Lo°o uoneiasp uvow {So6L‘o uvoul {(gh'o-Lt: » 10°O SNSavPVAD AOJ [BAIDU SSYIQ *SS¥PD UDALS UT
Ie} sjuaonb asoym sjuswttedxa jo saquinu yuasaidar soxe pwonsaa {Tey syuarjonb Arozeardsar yoryM ur ssep yuasasdas
Saxe [v}UOZLIOY pue ‘sndapjv4y Ut JuaTjoNb A1ojzestdsal yo uoynquystp Aouanberq—*f -o1g

Fe, SS, l j pe I ps" oP

roy ye “Tp |

SQOXLVYD [et

Re Seer. 2 ! | I | i | i | F | F Oe

B
a:
SQHINVUAV WY FE
eZ
=)
Bu

WAIGOdONYZ HI

[JULY

BOTANICAL GAZETTE

*6°O pue g’o us9MJaq ALOyD puvs pu Alayo IOF

*g°O puv Zo uaamjaq UIOYy MEY JOJ fan[Va *Q/*QQ L°O pue g°o UVaMjoq sat] WIN aBevF onjq puv ‘Jootde ‘yoved IO]
winwIxeut +(°939 ‘Z°O-1°O Wor) SyyUa} Aq st SurdnosZ ‘sanyea Juatjonb aqvorput sexe feyUOZOY {sIN990 anyRA JUaTONb yove
(IY Url sjuauItadxa Jo sadvyuaosed azvdIpuT Sox” [woIWIVA ‘avaovsoy UI sjuaNonb Aroyvudsal jo uosurdw0j—t “org

‘al l port n po l _|e | joer | joc” | ps l jos L for, ff, wi
SADTLFYD \ SVHINIWAF od
SASKNAD d s a / 3
‘ /
VITIWAd d \ kK \ ‘ a Or
NG \ , vorisawoad da {-
N N \ /
. \ P
\ 4 ee
“ ~ f a
/
\ “ if a FOISYAd SANAXd =
es gs
: ~sg ea
¥,
S. a)
OS
89
—

1921] SHERMAN—DORMANT SEEDS 15

are five quotients grouped discontinuously. The irregularity and
discontinuity of grouping lay the extreme values open to question
rom the mathematician’s point of view. In this instance experi-
mental evidence supports the mathematician’s feeling that certain
unusual factors must be working to produce the higher values,
inasmuch as these were obtained in experiments on seeds of the
1919 crop, tested within two days after their collection. The seeds
were not entirely freed from chaff and adherent scales, and in
each set mold developed freely during the experiment. The high
values obtained, therefore, represent the joint respiratory activity
of seeds and mold. These values have been allowed to stand in
the histogram to illustrate the value of such treatment of data as
a test of its uniformity, but they are not used in calculating the
average for the type quotient in table IV.

In fig. 4 the values for the respiratory quotients of the Rosaceae
are plotted in a percentage curve, the abscissas representing the
value of the quotients, and the ordinates representing the per-
centage of the total number of experiments on each seed, in which
each value occurred. The maximum percentage of the experi-
ments with the six rosaceous seeds, apricot, peach, cherry, sand
cherry, blue gage plum, and hawthorn, gives respiratory quotients
lying between 0. 60 and 0.90, the extreme range of the means for the
different seeds (table IV) being twenty-three classes, 0.648-0.876.
Within this range the maxima fall into three groups: those of
cherry and sand cherry, between 0.80 and 0.90; those of peach,
apricot, and blue gage plum, between 0.60 and 0.70; while that of
hawthorn lies intermediate between these values (0.70-0.80).
Thus the maximum for hawthorn falls very close to 0.756, the
"mean of the quotients (table IV) for these six seeds; and with the
exception of a single value for apricot all the quotients for these
rosaceous seeds lie within the range of the quotients of hawthorn.

Discussion

Increase in catalase activity during after-ripening of seeds and
during germination has been reported by numerous workers.
EcKERSON (19), by microchemical methods, found an increase in
the activity of catalase during the after-ripening of Crataegus, and

16 _ BOTANICAL GAZETTE [JULY

in the present investigation the same phenomenon was observed

macroscopically, under after-ripening and germinating conditions.
Such an increase during after-ripening is characteristic of seeds
with dormant embryos.

On the other hand, in Amaranthus retroflexus catalase activity
appears to be far less subject to fluctuation. CrRocKER and Har-
RINGTON (16) find surprisingly slight variation in the catalase
activity during after-ripening, which in Amaranthus occurs “during
the first three or four months in dry storage.” The activity for the
first month and a half after harvesting, as shown in table III, is
maintained at a very uniform rate. A comparison of the values
obtained on the imbibed seeds with those found by Crocker and
HarrINncTON for the dry powder indicates the uniformity of the
degree of activity in different seeds:

OXYGEN (CC.) LIBERATED AFTER

WEIGHT OF POWDER (GM.)

I minute 5 minutes ro minutes
0.10 dry powder..... 4.9 9.0 bi Ae
o.13 imbibed seeds. . . 3-9 6.1 x

The values for the dry seeds, however, are slightly higher than for
the imbibed, probably owing to the greater concentration of material
in a given weight. In this connection the results obtained by
CROCKER and HARRINGTON on samples of Amaranthus collected in
1894 are of interest. They found the catalase activity of these
twenty-three year old seeds but little diminished, although there
was complete loss of viability.

The extreme stability of the catalase activity is emphasized by the
fact that one 1894 sample gave values identical with those obtained
from one of the 1917 samples:

tg2t] SHERMAN—DORMANT SEEDS a ae §
D OXYGEN CC. LIBERATED AFTER
erraciooe Location
rminute | 3 minutes | 5 minutes | 10 minutes
PGI ee Oe, Pullman, Wash. 8.7 18.1 22.7 26.8
COOA peer. East Lansing, Mich. 5.7 18.1 22.7 26.8

In the seeds studied in the present investigation, the greatest
degree of activity was manifested by the rosaceous seeds (seeds
having dormant embryos).

Many plant and animal physiologists have me, inclined to
postulate a parallelism between catalase activity and respiratory
intensity (2, 3, 10, 11, 12, 13). In Acer saccharum (27) and
Juniperus virginiana (38) both catalase activity and respiratory
intensity increase as dormancy ends and germination begins.
In Crataegus catalase activity increased continuously up to the
twelfth day in the germinator (the time of the last determina-
tion), but the increase was not uniform. Respiratory intensity
increased up to the sixth day. From that time to the seventy-
seventh day it tended to decrease, but at an irregular rate
and with considerable fluctuation. In Amaranthus the respi-
ration, like the catalase activity, is maintained at a relatively
uniform rate for some time (176 days), but fluctuations in the one
are not coincident with fluctuations in the other, and at times may
be in an opposite direction. These facts are in harmony with the
decision to which their own studies led CROCKER and HaRRINGTON,
that “in Amaranthus seeds there is no evidence of a correlation
between catalase activity and respiratory intensity.”

That high catalase activity does not necessarily accompany a
high respiratory quotient or respiratory intensity (as indicated by
milligrams of carbon dioxide eliminated) is evident when the seeds
studied are arranged in descending order of these values, as given
in table VI

Although there are relatively few determinations of respiratory
values for resting seeds, the literature is rich in findings for other
plant parts. A comparison of these values, however, is often difficult
because of their variable form and the frequent absence of data
necessary for the determination of measured and calculated values.

18 BOTANICAL GAZETTE [JULY

In table VII results selected from numerous investigations have
been recast in such form as to make them comparable with the
results on resting seeds obtained in the present study.

In the following discussion of the respiration studies the results
are treated as they stand. It is recognized that the temperature
at which the experiments were carried out (20°-25° C.) was high,
and undoubtedly led to more vigorous respiration than occurs
at 10°C. The transfer from the latter temperature, at which
the seeds were stored when under after-ripening or germinating
conditions, to the higher temperature of the water bath, may in

TABLE VI
RESPIRATORY INTENSITY
CATALASE ACTIVITY CO./0:
Mg. CO, Mg. 0,
eliminated absorbed
t, A este et Chenopodium | Chenopodium | Rum
a Blue ; pod lone or eee Rumex Blue gage plum Chesca
3. Crataegus (imbibed)....... Amaranthus Apricot Burbank plum
4. Crataegus (as nese from
CN ee herry umex Sand cherry
&. Ameraninus,. 2500.03 Blue gage plum | Cherry Amaranthus
6: Chenopotiiom. 06560... and cherry Arvataivthies Cherry
7. Blue gage plum (as removed
front carpels) 6.20% 2. 6.3: Apricot Peach egus
S. Burbank phim... .,...<. +6, Burbank plum | Sand cherry Blue gage plum
bP OER Gee yews ci ie eevee ae each Burbank plum | Peach
MO i oe a hoi Crataegus Apricot
itself have accelerated respiration. In the case of apple, Har-

RINGTON (25) finds great diminution of the respiratory intensity at
low temperature. An investigation of the respiratory intensity of
the seeds used in the present instance for ten degree intervals of
temperature will throw light on this point.

The problem of the longevity of seeds is still unsolved, although
various theories have been advanced. Loss of vitality might result
from exhaustion of stored food, degeneration of enzymes, accumu-
lation in respiration or digestion of substances toxic to the seed, or
from still other internal changes in the seed substance inimical to
its life. Groves (14, 23) found that life duration of Triticum
sativum was a logarithmic function of the temperature, and
LEPESCHKIN’S time-temperature formula for the coagulation of

1921] SHERMAN—DORMANT SEEDS

TABLE VII

COMPARATIVE RESPIRATION OF DIFFERENT

PLANT ORGANS

Mg. CO, | Mg. O2

:
REF- | PER-
ORGAN RRENCE! ATURE CO./0; a Shae
CC.) “foe Gallet relat
Seedlings
NN ea SPs ag OS weld oka 5 13 | 0.98 | 55.92 41.54
pom COMIDUIIS Co os ee ees 5 20 0.96 | 37.67 33-54
oe ee ae aes oe yee 22 8 1.03 | 36.49 25.56
Steen of scion
edum reflexum
Large stems (day) .. oo. oc 5, 4% 5 31 | 0.98 | 23.83 17.70
ree stems (night) jo era 5 23 | 0.88] 17.05 14.14
ae t
young (day). oo a 5 25 77.1 3.86 3.83
. Very Yours (night) 6 ay eS 5 23 | 0.047| 0.412 6.40
tam
reer ni ae majus
thers. . = poe en a ea, 32 24 | 0.87 2.86 5.62
PN er Os 32 PPE ls sp Ba ge gee 2
Re Oy ie as 32 20 | 0.93 | 0.606 0.457
Acanthus mollis
PUOMNONNE elo ak kes 32 2I | 0.91 1.027 0.806
NO a 32 21 | 0.97 | 0.640 0.482
OEE eae GP cea rs bonis 32 21 0.79 0.538 0.518
BI i a i ae ies 32 20 | 0.81 | 0.546 0.589
ome saccharin. 521s di i algt Pecvant a lngkaree rte ay Gn and | pve pepa gee
Antirrhinum majus
oung... . Os Gewee ore ef eee 32 a4 cl I.35 613 1.455
Ao. ee 32 24 13 1.374 0.970
PU ae iy ec oy a 32 24 1.00 0.487
Acanthus mollis
td ER tear i aa ae 32 26 | 0.79 .088 0.952
wena es a tay 32 26 | 0.83 | 0.717 0.606
Wis cS ee 32 26 | 0.94] 0.633 0.485
Leaves = Seedlings
Fe ten ES paceman "Ys eee errs NER eee saree peer Ce, Veet
ee nite ep ee eee 37 26 | 0.99} 1.339 0.979
0: Etiolated | ‘ces uk ete ai 37 26 | 0.97 0.795
icia Faba
a. leav: besa owas Sas tae es 37 2t | 0.90] 1.226 0.988
Rated eaves, i ook se, 37 2r | 0.87 | 0.956 0.794
Leaves of Ligusirum j japonicum
Tones Bare 26 0.84 1.331 1.145
* —* . . .
ee aE nnn ie isl aay | cnet
Germinating seeds
Pd cig Otte Wuleerie es ab 0 Ue TGC i.
ryo
Hordeum wolwate . 2.5 oo. 5 cs 42 a4 | 1.00 | 1.337 [oeve see

a microchemical examination of numerous variegated leaves, ECkERsoN found oxidases, per-

oxidases, and catalases higher in the green than in the white portions.

BOTANICAL GAZETTE

TABLE VII—Continued

TEm- Mg. CO, | Mg. 0.
REF- | PER-
sacl ERENCE *eC) Eee Per hour per gm. fresh
(or imbibed) weight
stils
Taatuebtna Si ONGTE S65 ees 32 20 ¥.00-) | 2.106 0.864
Acanthus m
OUNE oes ce oh ey ceva ess 68% 32 2I 0.89 | 0.609 0.492
Adolescent PS Aceh anita cw aie 32 Qt 10.87) Ors3t 0.428
eS UR RY PE ae ia nee ie © 32 20 | 0.84 | 0.490 0.409
al See Pear ts Ces re rs 32 21 | 0.90 | 0.486 0.387
gs Ray seeds
BS cctv ec ue ee nos eas 30° lcedini cere OOM ss as aes
Vici Fal eee is Stk aia bik sca pr ee Phe sees ee O00 1k os shad
eS (eee et eo 30° bo Sle ee eee eee
Coates Pine Pee a ae 40 Poo are fee wu cae be aaa aa
F cand
Re Ay eli ne ENS 22 20-2) apy Ov pee: us suaers
Leases ond Telit —
i Nolet Ws Oates eee 23 24 ¥.03 | 0.798 0.565
song Sag on soaker aise aes enue cee 33 24 1.06 0.562 0.858
fg C0 31 DARA a ae teeth eae repo 33 24 88 | 0.554 0.444
€s
Triticum sativum seedling
(AEE NE Sete ke ee Ce 37 25 | 0.97] 0.788 0.588
TOO cis Boe Se Sees ace 37 25 | 0.98] 0.735 0.431
aden vulgare seedling
POR ee oir ies Se eee SESE USS 37 23 0.85 0.521 0.444
PAWIAIE oor as oe va es 37 a3. | 0.83 | 0.433 0.371
PND TION so oa ds ig cs 37 22. 1.0.97 | 0.361 0.212
i Minvatls INSU. oo. sk es ais 37 24. | 0.73 |. 0.354 0.182
Antirrhinum majus. <. ie 6 5s. se. 37 22 | 0.88 | 0.314 0.251
Malva syivestrit. 2.665 60.38.0650 04 37 ee 6. 9r | OragT 0.246
SYPNGA VUMATIE. oo oe ee cs 9 0 LOGE Behe is ae
oyrinid Vulgar. 21... cs kicks es 33 RS i nee co Vere pee
Wee DORIA oS ee, 9 10 O00 |. yee vost verve s tes
Fas toaritiing. 2 hc S25. 8 9 at 0.86 Fo es ae, a
FS WY UAT aw ees ve 9 SAT OBO be eee cela y eens +
PAM i a es 9 ot 0.00. bi igi aslo ec ae ve
Leaf blades
View mitive see 37 18 | 0.75 | 0.590 0.574
Rumes pecher: oo ec 37 17 | 0.76|] 0.288 0.276
nium Robertianum........... 37 18 10.72 | 0,272 0.275
DLYOMA GW. 6 i553 2. 2 37 17.5] 0.65 | 0.259 ©. 290
Leaf petioles
Vics GAVE ee a 37 18 | 0.88 | 0.327 0.207
UVOMIN GIONS | i hoe ee 37 t7.5|.0.87 | 0.184 0.154
eranium Robertianum............ 37 18 -O1 0.086 0.068
ROMS PEN ee a iS 37 17 | 0.80 | 0.064 0.058
Tendrils
: VICI GORPR 6c ose bac os a OS 37 18 | 0.90| 0.504 0.408
IBEVONIA CUGIDRs = 0 oa, 6 37 17.5| 1.02 | 0.221 0.157
Cladodes
Asparagus atone. 3 io ee ee 37 IS. 565981) 6.437 0.410
Ruscus hypophyilum A er re 37 tS }-O. 88 | 0.05% 0.067

1921] SHERMAN—DORMANT SEEDS

TABLE VII—Continued

ie ‘EM- Mg. COz | Mg. O;
F- | PER-
beecal ERENCE ATURE CO;/0s Per hour per gm. fresh
CC)? (or imbibed) weight
Phyllodes
Acacia megaloxylon........... pent oF 18 | 0.66} 0.233 0.257
Entire plant
Pelarvohium gonale 2. 2. a2) 422-1 ORAL Ss bere EA
ie page RYDE Ss Sook i ee BF eG O87 es ea
eel
Influence of warm bath.......... 35 a0 Se S188
14 hours in water at 38° Dees 35 PMS RARE Oo8 30 ice sess
14 hours in water at 20°C........ 35 Boe A Clare re ee.
Vicia SALIVE ee ee ee 37 18 | 0.86 0.292 0.247
RUMES DUICHED ees 37 ry 0.85 0.231 0.197
Spartacus albusy 3 37 18 | 0.96] 0.221 S109
Accacia megaloxylon... 6.6 66. ii ss 37 18 | 0.82 . 206 0.182
PVOnia Gioiea so i 37 17.5] 0.Q1 0.167 0.133
eer Robertiantimn, 6005.00, 37 18. | 0.04 })0:327 0:007
mbryanthemum nodiflorum...... 37 15.5} 1.00 | 0.076 0.055
‘ Ruseus Dypopby bie iis 37 15 | 0.58] 0.033 0.414
Convallaria
Untreated’: 2s ee as 35 £0 cde: Ot ees
After 8 hours in water at 38°C....| 35 Voda baer 144 yee ok
After 8 hours in water at 18°C....| 35 1 bn O:try 1 eee
Imbibed seeds
uni
sO Caveat 60. oo 38 25 | 0.05 | 6.480 | 0.4398
10g Gaye Gh PU. cei 38 25. | 0.68 | 0.2486 0.3192
ovcdayeat © Coo. 38 25 | 0.97 | 0.2354 ©. 2092
GOideve ots Gi 38 as. 1 06.07 | 0.2352 0.2152
ao anveat © Ci. ic 38 25 | 0.94] 0.218 0.1976
5 days at 5° C.. 1b 38 25- | D184 | -O,1gtF 0.1347
Table
a BMG ei IV 20 | 0.928} 0.175 o.141
PATON COME a as . 20 16 | 0.151 0.095
Peed a —_ nn a ae eee < 20 | 0.857} 0.113 0.096
Prunus cerasus var. Morello.......... “i 20 | 0.814] 0.108 0.091
P. domestica (blue eee ¢ 20 | 0.695) 0.107 ©. 109
P. ho oe Dees ss tes Ee . 20 | 0.878) 0.093 0.076
Ravi Kd 20 | 0.628 089 °. ep
P. domestica urbank plum)........ . 20 |.0.912} 0.083 °.
P. persi eee ty ne a * 20 | 0.675] 0.078 0.084
Cclan Seer c aac os bees Hee oes eee - 20 | 0.774) 0.06. 0.061
Zea Mays
MNO, ge 42 20 | 0.83 ARR eee,
PAMMOMOIE. co oi ceed ecko: 42 901 O85 1 O.08d be yo e y ss
AMG oe es ee ee ye ae Careers Bale
Pure oe Sawin d sues cies 42 OF 1 7s | SOOE fy tee tates
BANGS OORE 6 s 42 “61 6.97 | 0.004 is ces,
Hordeum ieee
Sitect 6608 os a 42 26 0.83 O. 908 poses
Sadaen (aunmer). visa ers css 42 23 | 0.68 | 0.078 |......---
Aleurone (summer)...........-- Pe Genrer) Mca O.088 (hos tein
Endosperm (winter).........-.- 42 15 |.0.58 | 0.019 |.-+---++-

22 BOTANICAL GAZETTE [yony

TABLE VII—Concluded

RE TEemM- Mg. CO; Mg. 0:
ORGAN Bence oes CO:/Os Per hour per gm. fresh
CC.) (or imbibed) weight
Pure endosperm (summer)....... 42 94°" 10.36. | 02010 oh aes
Pure endosperm (winter)........ 42 90. 1°O,49 b207007 4 aac. t
Aleurone (winter)............... We a, O.00T i avenners
ie oe oes ee ae, Vi 42 18 | 0.59 6.682) lice
Tubers
se
Cet Sa ieee Cpr oe Chee ie BA BE tes Sy eras
5 hom after quartering......... Oe 4d, Shp cae O:480P {ivi wie
MTOR oe aad by Sees 38 | I7-10)5 42. ODle Py eG
After 6 hours in water at 19. i, 2 Se GR Cae SOA CIO eT Co
After 5 hours in water at 40° C.. ae ere ae aio) tae) eee net eee
After storage at o° C. (starch
changed to sugar)............. 35 TOS Oe re a! dae rey ee
After 8 hours 2 per cent aqueous
ah ew eee Geen aie 5 10°). a OOS) eas
Mee Me os os ees ba es 21 18 | 1.09 O19 0.014
Coe ie eh ee a ee 21 18 1.06 | 0.078 0.164
poke DMM oo 2% 18° 9E 1.303) orayA 0.160
Triticum vuln a
19 per. cent water.............+. ee ge aca ar Renal “OMOEA 24 Convers
Soft red winter Waa (13 per cent
WaAtEE) ot as Fey Seek es ee Oe bak, oi 0, OOOPAI ii aes
Secale cereale
19 _ CONC WERE iy eects es cle BS Poe es 0, O00E (| cae ss
Zea Ma
19 at ROE WEE epee ee Ae eee ee O.000T fi ys eee:
JURITUR OLY 80068... . 60s ec cece 38 25 | 0.761 0.00098] 0.0011
Hordeum distichum
33 per c Gas oe ees 16 he A Peet farce
19-20 per Cent Water: co cy. Fgh SOE Per Sere O,OOOTS 6s cin.
45 Der Cent WAler. 6 oc re Gere ae Gant aer 7 ee eae
Algae
TOO eer ee 9 BOT eee eee
ee ENE (Eee RE RNa ly @ Werte | O66 te es aitiii sess ea
Fun,
Aspergillus niger, Raulin’s solution
Veseuntive mycelium si orning). en Ree ar oe ean ana ee ipe ee Se
Vegetative mycelium ccuaiiony ce eee any ee ery ACTOS
Fruiting myceli evening). .... ag BOF ee ei es
Wat d r cent salts,
blac origin SE ee "ee A gS Oe AP ae
Sterigmatocystis
In — catalina’
eA oe ee Be Nie ss Pic Pe saee eel cise cee eos
So ee SURRY. CoS ok 21 $0 LOGS bo allo ie oon
0.984 gm. tartaric acid........ Oe fice. BPO te as ee
©.75 gm. citric anhydride..... 21 BST A reise oe
° Om. malic acid... 3S. 21 90 PERO hoi ois ees
O.80 mm. Clint be. i... at 20 PY) TIES ea energy

TC. — Ge “ Piaget of the epidermis facilitates the entrance 6f oxygen to the tissues

—< suepeot ee — - ——— a fctating to know to what — the increased res P mtigts
wing ey is due to mec gaseous exchange t

actual metabolic changes in the wowed tame “i redeviwat ontonusdicenst err

1921] SHERMAN—DORMANT SEEDS 23

proteins was applicable as a temperature-life duration formula for
wheat grains, as LEPESCHKIN himself had found it applicable for
imbibed cells. Loss of viability in air-dry seeds, therefore, is
probably due to “‘a time-temperature denaturing of certain colloids
(probably proteins) of the embryo” (16). The retarding effect of
carbon dioxide upon germination has been shown by Kipp (28).
On the other hand, enzymes may persist and have a high degree
of activity in seeds which are no longer viable, as in Amaranthus,
or their activity may be greatly decreased without marked decrease
in percentage of germination, as in Johnson and Sudan grasses
(CrocKER 16). Exhaustion of stored food cannot be considered a
cause for decreased life duration in air-dry seeds, but in the case of
seeds lying in the soil the situation is different. Such seeds would
have a high water content, favoring chemical action, whether
respiration or digestion. The actual occurrence of such reactions
of course would depend upon oxygen supply, temperature, enzymes
present, and the extent to which by-products (carbon dioxide, etc.)
were removed. In such seeds, of which Amaranthus is a typical
example, the life duration might easily be limited by the amount
of stored substance present or by the rapidity with which it was
respired or digested.

CROCKER and HARRINGTON (16), in studying the behavior of
Johnson grass, found that storage of freshly harvested seed at 20° C.
in the germinator led to an increased or secondary dormancy, a
phenomenon frequently observed in seeds as a result of unfavorable
germinating conditions. They suggest that such a deepened dor-
mancy, if accompanied by a decreased respiration, may have an
important bearing upon the longevity of seeds in the soil by
lengthening the period necessary for the reduction of stored foods.
From their own experiments on the respiration of Johnson grass
they estimate the possible longevity of this seed as follows:

If 75 per cent of the weight of the seed can be respired before death occurs,
secondarily dormant Johnson grass seeds could lie in a germinator for 9.8
years at 20°C. before death would occur from exhaustion of stored foods.
The period at 10° C. would likely be 2 to 3 times 9.8 years, in accord with
the temperature quotient for respiration. Without such a reduction in respira-
tory intensity the possible longevity would be a little more than one-third as
great, figured on the initial rate in the active seeds. Even if the longevity of
imbibed seeds in the soil be dependent upon some contingent other than

24 BOTANICAL GAZETTE [JULY

exhaustion of stored food, this reduction in respiration is of significance. It
will leave more stored material for building purposes in case germination does
occur after a considerable period in the soil.

A similar calculation has been made of the rapidity with which
Amaranthus seeds respiring at the rate observed (table IV) would
exhaust their storage substance. The estimate is based on a
moisture content of 47.43 per cent, and Woo’s (44) analysis show-
ing 47 per cent starch. On this basis the possible longevity is
160 days at the experimental temperature, 20°-25°C. This
temperature is high, and respiration of stored food would cer-
tainly proceed more slowly at the lower temperature of the soil.
Moreover, since observation (7, 8, 24, 41) shows the actual longevity
of Amaranthus in the soil to be more than thirty years, there must
be tremendous curtailment of metabolism under these conditions,
with exceedingly slow use of the reserve. Even in the laboratory,
dry-stored at room temperature and imbibed just before using, the
seeds were viable 176 days after harvesting, and CROCKER reports
that 200 days in the germinator at 20°C. does not alter their
viability. If the 47 per cent fat contained in hawthorn be taken
as stearin, the longevity of this seed when removed from the
carpel, with 60 per cent water content, would be about 170 days
at the rate of respiration observed (table IV) for the same tem-
perature. Actually the seeds are viable for a longer time.

In all the rosaceous seeds studied variability of respiratory
values was marked. Since the value of the respiratory quotient is
based upon the volumes of CO, eliminated and of O, absorbed, it
may serve as a convenient index of this variability. The total
range of the quotient values of the six rosaceous seeds is 0. 31-1 .14.
The extremes for individual seeds are as follows:

PAwihOrn ee a eae ee
POR ox, ©.56-0.06
Apricot . 0.31-0.80
Cherry 0.76-1 .04
Sand che er ea 0.75-1.05
Blue gage phim ek Se
Burbenk phim | . ©.72-1.04

As shown in fig. 4, with the exception of a single experiment on
apricot, the quotients for all the other rosaceous seeds fall within
the range of those of hawthorn. The mean for hawthorn (0.774)

1921] SHERMAN—DORMANT SEEDS 25

lies within o.02 of the mean of the means (table IV) for the other
seeds (0-756). The rosaceous seeds, therefore, exhibit a marked
similarity to one another in their respiratory behavior. If it may
safely be assumed, as has been the tendency, especially among
animal physiologists, that the character of respiration and particu-
larly of the respiratory quotient depends upon the kind of sub-
stance oxidized, such a similarity would be expected, since in all
these seeds the storage substance is chiefly fat.

On the other hand, in Amaranthus, although fluctuations in the
carbon dioxide elimination and the oxygen absorption occur, and
that too not always in the same, but occasionally in opposing, direc-
tions, the respiratory quotient remains relatively stable through-
out a period of 176 days. The contrast in the behavior of the
Rosaceae and of Amaranthus may be due in part to the difference
in storage material, since Amaranthus contains little fatty sub-
stance (44), but much starch. This latter substance constitutes
the reserve in Chenopodium and in Rumex also. It is probable,
however, that other factors are responsible for the extreme varia-
bility of the rosaceous quotients.

The embryo of Amaranthus is not dormant. “Any time after
maturity naked embryos are capable of immediate growth”’ (16).
The six rosaceous seeds have dormant embryos. This dormancy,
however, is of unequal intensity in different parts of the embryo.

Davis and Rose (17) and EckEerson (19) have emphasized the
difference in development of cotyledons and of the hypocotyl in
Crataegus. Davis (18) finds a similar situation in the peach. It is
therefore reasonable to suppose that these two parts of the embryo,
cotyledons and hypocotyl, differing as they do physiologically and
chemically, may differ in their metabolic activity and specifically
in their oxygen absorption and carbon dioxide elimination. These
differences at times may counterbalance, or at times augment, each
other; or it may be that now the intensity of the hypocotyl, now
that of the cotyledons, may predominate and determine the metabo-
lism characteristic of the seed as a whole.

An analogous situation is reported by MatcE (32) for stamens.
In general the respiratory intensity of the adult stamen is less than
that of the young organ, but this decreased intensity is differently
attained in different plants. In some there is a steady decrease

26 BOTANICAL GAZETTE [JULY

from youth to age, while in others there may be an increase to a
maximum followed by decline to the adult intensity, or a fall to a
minimum succeeded by a return to a rate slightly lower than that
at the beginning. Study of the filament and anther separately
reveals the fact that their respiratory intensities are distinctly
different, the anther undergoing a sort of grand period of respira-
tory intensity, while the intensity of the filament increases regu-
larly from immaturity to maturity. The intensity of respiration
of the stamen as a whole therefore is the resultant between these
two respiratory intensities.

Great diversity of opinion exists as to the importance attach-
ing to the respiratory quotient as an index of metabolism. In
seeds like Amaranthus and Chenopodium the quotient would
appear to be of significance because of its stability. The varia-
bility of the quotient in Rosaceae at first might appear to militate
against its possessing any significance. When, however, this
variability of the quotient is found to characterize a group pos-
sessing fundamental physiological and chemical features in com-
mon, it would seem that even here some significance might attach
to the quotient. It may be of little value as indicating the material
oxidized, but it may have considerable importance as indicating a
situation due to the interplay of several factors. The quotient
percentage curves (fig. 4) and the frequency histograms (fig. 3)
show more clearly than do the tabulated data the general trend of
respiration. From them can be seen that even with their varia-—
bility the values for hawthorn and the other Rosaceae tend to fall
into small groups about one largest assemblage. The latter, there-
fore, may be considered indicative of the type respiratory value for
the seed.

In Chenopodium and Amaranthus the massing of the quotients
is within a narrow range, and the type is more marked. Treat-
ment of data in this way, therefore, may serve as a further check
on the uniformity of conditions under which the experiments are
carried out, and perhaps on the reliability of the method.

In this connection it is interesting to note that the curves in
fig. 3 are of the kind found by Prarson to be typical for botanical
measurements, limited skew curves (‘‘axis of the abcissas limited

1921] SHERMAN—DORMANT SEEDS 27

on both sides, curve unsymmetrical’’). Zoological curves, on the
contrary, are unlimited skew curves (“‘axis of abcissas unlimited
on both sides, curve unsymmetrical,’ 45). A possible explanation
of this difference in behavior between plants and animals that sug-
gests itself is the complication of the results of zoological experi-
mentation due to the independent volition of the animal. Plants,
placed under a given set of conditions, vary little in behavior,
while uniformity of behavior in the case of different animals, or
even in the case of the same animal upon successive occasions, is
beyond control.

These respiratory studies in no wise answer the queries that
they suggest. They are rather preliminary to further investiga-
tion. Upon one point, the difference in respiration between dor-
mant and after-ripened but still resting Crataegus seeds, some data
have already been obtained. That the respiration is slightly
higher in the after-ripened than in the dormant seed seems well
established. Further study of this point, however, is necessary.

Summary

1. The respiratory intensity, that is, the mg. CO, eliminated
per gram imbibed seeds per hour, was determined experimentally
for Amaranthus retroflecus, Chenopodium album, and Rumex
crispus, as well as for Crataegus and certain drupaceous Rosaceae.
Determinations of the catalase activity were also made for most
of the seeds.

2. Catalase activity increases in Crataegus under after-ripening
and germinating conditions (10° C.), up to the forty-second day.
The slightly higher value for the 128th day may represent: (1) a
continued increase at an extremely slow rate; (2) a limit depending
on the amount of dioxogen used (5cc.); (3) a falling off, as a
result of secondary dormancy, of an activity whose maximum
occurred at the completion of after-ripening (about the ninetieth
day). Respiration reaches a maximum intensity much earlier
(sixth to eighth day), and thereafter exhibits a slow and fluctuating
decline, at least to the seventy-seventh day.

3. In Amaranthus both catalase activity and respiration are rela-
tively stable. Fluctuations in catalase activity and in respiratory

28 BOTANICAL GAZETTE [JULY

intensity do not occur simultaneously, and may be in opposite
directions.

4. The respiratory quotient and respiratory intensity vary
markedly for different seeds, and in the Rosaceae for different lots
of the same kind of seed under precisely similar experimental con-
ditions. The respiratory quotient in Amaranthus and Chenopodium
is markedly stable. Since in the Rosaceae the embryo is dormant,
while in the other two seeds it is not, it may be that this difference
in behavior is characteristic of seeds with dormant embryos, and
the greater stability of respiration in Amaranthus and in Cheno-
podium represents the attainment of a more stable metabolism in
these seeds.

5. Stability or variability of the quotient may be of signifi-
cance as indicative of the possibility of an interplay of several
factors on the metabolism. In Crataegus, and presumably in the
other Rosaceae, the marked variability is probably the resultant
between the respiration of the dormant hypocotyl and that of the
mature cotyledons.

6. The arrangement of the respiratory quotients for each seed
in a curve showing the percentages of the experiments with each
seed giving each value, and in frequency histograms in which are
plotted the actual number of experiments in which each quotient
value occurred, indicates the tendency of each seed toward a
typical respiration. The quotients for Chenopodium and Amaran-
thus are 0.928 and 0.856 respectively, while those of the Rosaceae
form three groups within a range of 0.118. In the first group,
between 0.648 and 0.7, fall the quotients for apricot, peach, and
blue gage plum; in the third, between 0.8 and 0.876, those of
cherry and sand-cherry; while that of hawthorn, 0.774, lies mid-
way between.

Grateful acknowledgment is made to Professor WILLIAM
CRocKER and to Dr. Sopuia H. Eckerson for the suggestion and
the direction of this study, and to Dr. B. I. Mrzter for her assist-
ance in graphing the data.

UNIVERSITY OF CHICAGO

1921] SHERMAN—DORMANT SEEDS 29

fo.)

“I

LITERATURE CITED

- APPLEMAN, C. O., Some observations on catalase. Bor. GAz. §2:182-102.

glt.
———,, Relation of catalase and oxidase to respiration in plants. Md.
Agric. Expt. Sta. Bull. IQI. IQISs.

ae and catalase activity in sweet corn. Amer. Jour. Bot.
5:207-209. IQI

ATwoop, W. M., A ee study-of the germination of Avena fatua.
Bor. Gaz. 57: s86-4x4.

AUBERT, E., peti sur la respiration et l’assimilation des plantes
grasses, Rev, Gén. Botanique 4:203-219, 273-282, 320-331, 337-353,
373-391, 421-441, 497-502, 558-568. 1892

. Battey, C. H., and Gurjar, A.M. : Bewpiration of stored wheat. Jour.

Agric. Res. 13: 685-713. 19

18.
- BEALE, W,J., gig vitality of seeds buried in the soil. Mich. Agric. Exper.

Sta. Bull. 5.

8. ———. hash - seeds buried in the soil. Proc. 31st Ann. Meeting Soc.

Lal
°

- GARREAU,

Prom. Sci. IgIo.
Bonnier, G., and Manatn, L., Recherches sur la respiration des feuilles
a Vobscurité. Ann. Sci. Nat. Bot. VI. 19:216-255. 188

- BurGE, W. E., Relation between the amount of catalase in the different

muscles of the body and the amount of work done by these muscles.
Amer. Jour. Physiology 41:153-161. 1916

comparison of the amount of catalase in the muscles of active
and inactive animals. Ibid. 42:600. 1916-1
mparison of the catalase content of ‘the breast muscle of wild
pigeons mee of bantam chickens. Science N.S. 46:440. 1917.
, Catalase content of luminous and non-luminous insects compared.
Ibid. ah: 295. IQ17.

- CROCKER, Wm., Mechanics of dormancy in seeds. Amer. Jour. Bot.

3299-120. 1916.

- CROCKER, Wm., and Davis, W. E., Delayed germination in Alisma Plan-

tago. Bort. Gaz. 58:285-321. 1914

- CROCKER, Wm., and HarrincrTon, G. T., Catalase and oxidase content of

seeds in relation to their dormancy, age, vitality, and respiration. Jour.
Agric. Res. 15:137-174. 1918.

- Davis, W. E., and Rost, R. C., The effect of external conditions upon the

after-ripening of the seeds of Crataegus seme Bor. Gaz. 54:49-62. 1912.
Davis, W. E., Unpublished work on the

- Eckerson, S. H., A cages and ae study of after-ripening.

Bor. Gaz. 55: 286-299
, De la sabiaiien chez les plantes. Ann. Sci. Nat. Bot.
TI. 15:1-36. 1851

- GERBER, C., Recherches sur la maturation des fruits charnus. Ann. Sci.

Nat. Bot. VIL. 421-277.

- GRaFeE, V., Erashrungiphysislogiaches Praktikum héherer Pflanzen. 1914.

BOTANICAL GAZETTE [JULY

. Groves, J. F., Temperature and life duration of seeds. Bor. Gaz. 63:
917.

169-189. 1

. Harrincton, G. T. Fie degasetete value of impermeable seeds. Jour. Agric.

Res. 6:761-796. 1

-_—— ae week on the apple.

FARRINGTON, G. T., and Crocker, Wm., Respiration measurements
(unpublished).

A co H. A., Physiological study of maple seeds. Bor. GAz. 69:127-152.

‘ Krs, F., The controlling influence of carbon dioxide in the maturation,

dormancy, and germination of seeds. Proc. Roy. Soc. Lond. B. 87: 408-
421, 609-623. 1914; 89:136-156. 1916.

. Korxwirz, R., Uber die Athmung ruhender Samen. Ber. Deutsch. Bot.

stiles 19:285-287. 1901.

, M., Uber die Atmung keimender Samen unter Druck. Ber.
Beatech, Bot. Gesells. 23: 100-104. 1905.
Macness, J. R., Composition of ae in intercellular spaces of apples and
potatoes. Bor. Gaz. 70:308-316. 1
Matcre, Mme., Recherches sur la es de l’étamine et du pistil.
Rev. Gén. Botanique 21:32-38. 1909.
———.,, Recherches sur la sane des differents piéces florales. Ann.
Sci. Net. B Bot. IX. 14:1-62. 1911
MaguennE, L., Sur le mecanisme de la respiration végétale. Compt.
Rend. 119: mina eke ty 1894.

. Mijtter-Tuurecav, H., and ScHNEIDER-ORELLI, O., Beitrige sur Kenntnis

der Lebensvorginge i in ruhenden Pflanzenteilen. L Flora. 101:309-372-
IQIO; sie “< 104:385-441. IQII-I912

Nasoxicu, A. J., Uber den Einfliiss de Sterilization der Samen auf die
At rs "Bet. Deutsch. Bot. Gesells. 21:279-291. 1903.

Nicotas, G., Recherches sur la respiration des organes végétatif des
plantes vasculaizes. Ann. Sci. Nat. Bot. IX. 10:1-113. 1909.

PACK D. Aa eee and germination of Juniperus communis.
Bor. Gaz, 91:32-60. 19

PuRIEWITSCH, K. nana Untersuchungen tiber Pflanzenathmung.
Jahrb. Wiss. Bot. 35:573-010. 1900

Rose, R. C., After-ripening and Sa of seeds of Tilia, Sambucus,
and Rubus. Bor. Gaz. 67:281-308. 1

SHULL, G. H., The longevity of uaa seeds. Plant World 17:320-
337+ 1914.

STOWARD, F., ee “gpa cca respiration in certain seeds. Ann. Botany
22:415-648. 1

Waite, J., see and the latent life of resting seeds. Proc. Roy. Soc.
Lond. B. 81:417-442. 1909.

Woo, M. L., Chemical constituents of Amaranthus retroflexcus. Bot. GAz.
68:313-344. Igt9.

5. ZIZEK, F., Statistical averages. 10913.

LEAVES OF THE HELOBIEAE’
AGNES ARBER
(WITH PLATE 1)
Introduction

In a paper published in 1918 (1), the phyllode theory of the
monocotyledonous leaf was discussed in general terms, and in
subsequent articles in this and other journals (2, 3, 4, 5) attempts
have been made to trace the results of applying this theory in
various special cases. In the present paper, it is proposed to
study the leaves of the Helobieae, to see how far the phyllode
theory will help toward interpreting them. I am indebted for
material to Professor OSTENFELD of Copenhagen; to the Director
of the Royal Botanic Gardens, Kew; to the Keeper of the Depart-
ment of Botany, British Museum (Natural History); and to the
Superintendent of the Cambridge Botanic Garden.

The Helobieae of ENGLER consist of seven families of water or
marsh plants. Their common characters are difficult to define,
but they are united by a macropodous embryo, and on the whole
they appear to form a fairly coherent group. The seven families
will be considered individually, and then the general conclusions
drawn. Since I believe that the Alismaceae and their allies include
the less specialized types within the cohort, these families will be
discussed first, instead of following ENGLER’s sequence.

Alismaceae

The literature on the protean leaf forms of the Alismaceae
has been summarized elsewhere (6). The point to emphasize now
is that the leaves of this family fall into three categories.

1. Leaves with a sheathing base and a limb, more or less radial
in form and phyllodic in anatomy.—This form of leaf is rare in
the family, but is found in the Sagittarias of the S. teres group, to
which S. isoetiformis Smith and S. teres Watson belong. Fig. 1

This paper represents part of the work carried out during the tenure of a Keddey
Fletcher-Warr Studentship of the University of London.

31[ [Botanical Gazette, vol. 72

32 BOTANICAL GAZETTE [yuLy

represents a transverse section of the awl-like limb of one of these
peculiar American Sagittarias. For comparison, by its side is a
transverse section of the petiole of the normal arrowhead leaf of
S. sagittifolia L. It will be recognized at once that both in form
and structure they are essentially identical, and it will probably
be generally agreed that the leaf of S. teres is equivalent to the
arrowhead leaf of S. sagittifolia, minus the blade. Domi (9)
evidently takes this view, for he uses the term “‘Phyllodien”’ in
describing these leaves.

2. Leaves with a sheathing base and a flat ribbon-like limb.—
These leaves are exceedingly common in the family, and are
regarded as equivalent in morphological value to type 1, since in
S. sagittifolia intermediate forms can be traced between thin
ribbon leaves with a single row of bundles (fig. 3) and the almost
radial petioles of the arrowhead type (fig. 2). For instance,
among the transitional leaves between the juvenile ribbon and
the mature arrowhead, a leaf was examined which was ribbon-like,
but with a spathulate apex. It was found that the ribbon region
was thicker than in the simple ribbon leaf, and, instead of having
one series of bundles only, it had one small additional bundle
above and one below the median bundle, and one below each of
the main laterals, that above the median bundle being inverted.
This showed an approach to the radial structure of the S. teres
group.

3. Leaves with a differentiated pseudo-lamina.—I have set forth
elsewhere (1) the reasons for regarding the blade of such leaves as
the arrowhead as “pseudo-laminae,”’ produced by the expansion of
the distal part of the petiolar phyllode. How far the form and
venation of the blades of the Alismaceae harmonize with this
interpretation may now be considered. In some of the oval or
cordate leaf forms there is little difficulty in seeing how the skeleton
of the blade might be produced merely by the separation of the
parallel petiolar veins, which at the apex return to their original
approximation. This is the case, for instance, in Alisma parnassi-
olium Bassi var. majus (fig. 6). A further development on the
same lines has taken place in A. nymphaeifolium Griseb. (fig. 8), in
which the veins v and 0’, curving into the basal lobes, give off second-

1921] ARBER—LEAVES OF HELOBIEAE 33

ary veins, more or less parallel to themselves, and thus, without any
essentially fresh departure, achieve a venation determining the
auricled form of the leaf. It is probable, however, that such leaves
do not form a transition to the arrowhead type, but that the
latter is arrived at by a separate route.

It will be seen on examining fig. 5 (Limnophyton obtusifolium)
and fig. g (Sagittaria Greggii) that the principal veins are the
midrib (a) and the two veins (0, 6’) passing into the cusps. In some
species these cusps are very conspicuous; in S. longiloba they
may be two or three times the length of the median segment.
It is not probable that the arrowhead type of venation is derivable
from that shown in fig. 8, which is, moreover, a rarity in the family.
It is suggested that the veins } and b’ are, as it were, a repetition
of the midrib, and have originated phylogenetically by its chorisis.
Their morphological relation to the midrib would thus be equivalent
to the relation borne by the tendrils of Smilax to the petiole,
according to a hypothesis put forward in a previous paper in this
journal (4). Of course it is impossible to offer any definite proof
of such a theory, but it probably makes the nature of the arrowhead
leaf a shade less obscure. It seems to account for the lack of
any genuinely transitional forms between the types of venation
characterizing the oval and arrowhead varieties of pseudo-lamina.
It is true that the intermediate forms have very short cusps, but
their venation is distinctly of the arrowhead type.

Butomaceae

The Butomaceae are so closely related to the Alismaceae that
they are sometimes regarded merely as a tribe of the latter family.
Among the Butomaceae we find examples of the three types of leaf
enumerated under the Alismaceae. Butomus umbellatus L. has a
leaf with a sheathing base, and an upper region which is triangular
in section and phyllodic in anatomy (17). On the other hand,
Hydrocleis Commersonii Rich. and H. parviflora Seub. have both
ribbon leaves and leaves with a petiole and pseudolamina (10, 18,
20). The published figures of these ribbon leaves suggest that they
are equivalent to the ribbon leaves of Sagittaria, but I have not
had the opportunity of examining their anatomy.

34 BOTANICAL GAZETTE | [JULY

Juncaginaceae

Of the five genera of Juncaginaceae, none possesses leaves with
pseudo-laminae. Certain species of Triglochin have ribbon-like
leaves, for example, T. montevidense Spreng., figured by SEUBERT
(18, pl. XII), and 7. procerum R.Br. It is hoped to deal with
the leaf anatomy of this genus in a later paper. Except in the
case of these few ribbon-leaved species, all the five genera have
leaves with a sheathing base and a radial or ensiform limb, with
a typically phyllodic anatomy. In Triglochin, Lilaea, and Scheuch-
zeria, a ligule generally marks the boundary between sheath and
limb (9). Fig. 7 shows the transverse section of the limb of the
leaf of Scheuchzeria palustris L. Its curious asymmetry has been
figured and commented on by RAUNKIAER (15). The leaf of
the monotypic Maundia, judging from BucHENAUv’s figure of the
transverse section (8, fig. 7, p. xvi), is phyllodic, and similar to
that of Triglochin maritimum (1). I have cut the leaf of the
monotypic Lilaea subulata Humb. et Bonpl., and, although the
herbarium material available was not very favorable for anatomical
work, it was obvious that here also the structure is phyllodic.
The leaf, which is described as awl-shaped and cylindrical in the
fresh condition, is supplied by a series of small peripheral bundles in
addition to three main strands. Hirronymus (11), in a Spanish
monograph of Lilaea published forty years ago, definitely states
that the leaves of this plant consist only of sheath and petiole,
the lamina being unrepresented.

It was interesting to find, on examining the fifth genus (the
monotypic Tetroncium magellanicum Willd.) that the leaf is unusual
among the Helobieae in being of the ensiform type, and in having
a bundle system identical with that of the isobilateral equitant
leaves which are so familiar, for instance, in Iris. In fig. 4, A shows
the structure of the sheath region, B the transition to the limb,
and C the limb itself, which has a close anatomical resemblance to
that of Tofieldia calyculata Wahl., one of the equitant members of
the Liliaceae (1). F ibrous sheaths are associated with the bundles.

Potamogetonaceae

In this family there are three types of leaf, corresponding to
those met with in the Alismaceae and Butomaceae. The rarest

1921] ARBER—LEAVES OF HELOBIEAE 35

type is the leaf with a sheathing base and more or less radial limb
with phyllodic anatomy. This leaf form is found in Cymodocea
isoetifolia Aschers. (fig. 11), described by SAUVAGEAU (16) and
OSTENFELD (14). A ring of bundles surrounds the median strand.
The same genus also includes leaves in which the limb is flat and
furnished with only one series of bundles (as C. nodosa Aschers.,
fig. 12), while C. manatorum Aschers. (fig. 10), with its more or less
terete leaf, traversed by three strands only, forms an intermediate
type. In each species there is a ligule, clearly delimiting the
sheath from the petiolar region.

In Potamogeton the leaves of some species, like the air leaves of
many Alismaceae, possess pseudo-laminae. In P. natans L. there
are, in addition, bladeless, terete, phyllodic leaves, corresponding
exactly in structure and anatomy to the petioles of the fully
developed ‘leaves (16), and which may be regarded as equivalent to
the leaves of Cymodocea isoetifolia. P. natans also has leaves
showing a further degree of reduction, but instead of being ribbon-
like, as in the Alismaceae, they consist almost entirely of the highly
developed axillary stipules or ligules.

Naiadaceae

The leaves of the Naiadaceae are much reduced, but they have
a sheath and a thin flat limb, and thus correspond to the ribbon
leaves of Sagittaria.

Aponogetonaceae

Only the one genus, A ponogeton, is included in the Aponogetona-
ceae. Most of the species have leaves with a differentiated sheath,
petiole, and pseudo-lamina, but A. vallisnerioides Bak. has ligulate
ribbon leaves, described (7) as resembling those of Vallisneria, while
in A. spathaceum E. Mey. var. junceum Hook. f. (12) semiterete
leaves with a sheathing base are found. A piece of a leaf of this
variety which was examined did not include the distal part of the
leaf, but showed the structure of the transition region between
sheath and limb. In addition to the three main bundles, which
HOoKeEr indicates in a slightly magnified transverse section which
he figures, there are a number of small peripheral bundles. The
Structure is thus closely equivalent to that of the petiole of such a
species as A ponogeton distachyum Thunb.

36 BOTANICAL GAZETTE [JULY

Hydrocharitaceae
In the Hydrocharitaceae all three types of leaf which have been
‘considered are found. In Siratiotes and Enhalus there is no blade,
and the occurrence of inverted bundles (13, 19) gives a phyllodic
aspect to the anatomy. These leaves may be regarded as equiva-
lent to that of Butomus, but in Stratiotes there is no sheath, although
this region is developed in Enhalus. Hvydrocharis has a leaf with a
stipulate sheath, a petiole, and a pseudo-lamina, while the leaves
of Vallisneria and Thalassia are similar to the ribbon leaves of
Sagittaria. Vallisneria has a sheath which may easily be over-
looked, while in Elodea this region is entirely lacking (9).

Conclusions

A comparison of the leaf structure in the various families belong-
ing to the Helobieae shows the repeated occurrence of that leaf
type in which there is a sheathing base succeeded by a bladeless limb,
in appearance and structure recalling a petiole. Stich leaves,
instances of which are met with in six of the seven families, are
regarded as typical petiolar phyllodes. This simple phyllodic
form of leaf is most characteristically developed in the Juncagina-
ceae, where it occurs in all five genera. The leaves in this family are |
generally more or less radial, except in Tetroncium, where they
are ensiform and Jris-like. In the other families leaves of approxi-
mately radial structure occur more or less sporadically, or as
rarities, except in the Naiadaceae, where they are entirely lacking.
The extreme reduction of the one genus Naias, which constitutes
the family, however, makes the absence of such leaves by no
means surprising.

In each of the seven families examples of a leaf with a sheathing
base and flat ribbon-like limb are found. This leaf is regarded as
equivalent to the more obviously phyllodic type of leaf just dis-
cussed. Two lines of evidence point to this conclusion: (1) within
the single species Sagittaria sagittifolia L. transitions, both in
external form and internal structure, can be found between typical
ribbon leaves and petioles; and (2) within Cymodocea not only typical
ribbon leaves (as C. nodosa, fig. 12) and typical petiolar leaves (as
C. isoetifolia, fig. 11) are found, but also in C. manatorum (fig. 10)
there is an intermediate link between these two types.

1921] ARBER—LEAVES OF HELOBIEAE 37

The third and last leaf type, that in which there is a differenti-
ated blade, occurs in five of the seven families, the exceptions
being the Juncaginaceae and Naiadaceae. It is not necessary
here to discuss the evidence, based partly on a study of the suc-
cession of leaf forms in the ontogeny, and partly anatomical, which
has led to the conclusion that these blades are ‘‘pseudo-laminae,”’
originating by the expansion of the apex of the petiolar phyllode,
for this question has been considered elsewhere (1, 6). The
present paper adds a study of the significance of the blade venation
of the Alismaceae.

The final impression left by this survey of the leaves of the
Helobieae is that there has been a remarkable parallelism of develop-
ment within the different families. The three leaf types enumerated
recur throughout the cohort in forms which, although modified in
various ways, are identical in essentials.

Batrour LABORATORY
CAMBRIDGE, ENGLAND

LITERATURE CITED

1. ARBER, AGNES, The phyllode theory of the monocotyledonous leaf, with

special reference to anatomical evidence. Ann. Botany 32: 465-501. 1918.
, The vegetative morphology of Pistia and the Lemnaceae. Proc.
Roy. Soc. B. 91:96-103. r9r9.

, Leaf base phyllodes among the Liliaceae. Bot. GAZ. 69:337-340.
1920.
4- , Tendrils of Smilax. Bort. Gaz. 69:438-442. pl. 22. 1920
5- , On the leaf structure of certain Liliaceae, considered in relation to

the phyllode theory. Ann. Botany 34:447-465. 1920

———, Water plants: a study of aquatic Angiosperms. Cambridge

University Press. 1920. ;

Baker, J. G., and Grant, J. A., The botany of the Speke and Grant

expedition. Trans. Linn. Soc. 29:1~190. 18

8. BUCHENAU, FE; Scheuchzeriaceae i in Das Pflanzenreich IV. 14:1-20. 1903.

9- Domnin, K.., iiber die Stipular-
bildungen. Ann. Jard. Bot. Buit. “24: 3117-326. pls. IT. 191t.

to. Ernst, A., Uber Stufengang und Entwickelung der Blatter von Hydrocleis
nymphoides Buchenau (Limnocharis Humboldtii C.L. Richard). Bot. Zeit.
30:518-520. 1872

11. HiERonyMus, G.

, Monografia de Lilaea subulata. Act. Acad. Nac. Ciencias

en Cérdoba. 4:1-52. pls. 5. 1882.

12. Hooker, J. D., Aponogeton ee E. Mey. var. junceum. Curtis’s
Bot. Mag. 34: pl. 6399. 1878.

38 BOTANICAL GAZETTE [JULY

13. Macnus, P., Uber die Anatomie der epee a fare a Sitz.-Ber.
Gesells. Nat. Freunde Berlin 1870.

14. OSTENFELD, C. H., Contributions to West Australian botany. Part I.
Introduction. The sea-grasses of West Australia. Dansk Bot. Arkiv
2:1-44. 1916.

15. RAUNKIAER, C., De Danske Blomsterplanters ee I. Enkim-
bladede, 1. Helobieae. 1-138. Copenhagen. 1896.

16, SAUVAGEAU, C., Sur les feuilles de pape Sioniecky ica aquatiques.
Ann. Sci. Nat. VIL Bot. 13:103-296. 1891

, Sur la feuille des Butomées. Ann. Sd, Nat. VII. Bot. 17: 295-326.

1893.
18. SEUBERT, M., in Marttvs, Flora Brasiliensis 3: part 1. 1842-71.
19. SOLEREDER, H., Systematisch-anatomische cee - Blattes der
Hydrocharitaceen. Beih. Bot. Centralbl. 30:24—-104.
. WACHT W., Beitrage zur Kenntniss einiger Waesidaicet: Flora
83: oa: 1897.
EXPLANATION OF PLATE I

The plate shows the xylem in black, the phloem in white, the fibers (f)

saieeee As the outlines of lacunae in dotted lines.

1.—Sagittaria of S. teres group: transverse section of limb of leaf f,
interest fibrous sheath of bundle (slight asymmetry of section probably due
to incomplete recovery of edo —— used; Georgia Plants. Roland
Harper. 1473. Ex Herb. Brit.

Fic. 2.—Sagittaria sagiitifolia 1 e Sea section of petiole close to
blade, fibrous bundle — (less highly developed than in species shown in
fig. 1) not indicated;

Fic. 3. Sastiote sanueoles L.: transverse section of saat ribbon leaf,
X23

Nv
°

Fic. 4.—Tetroncium genenageanss Nee transverse sections of leaf;
A, sheath, B, transition to limb; C, limb;
G. 5.—Limnophyton oblscss! olden Mia: are of Jen; a, em b, b’ cusp
veins poets of margin probably an effect of drying); Xo
ms 1G. 6.—Alisma parnassifolium Bassi var. majus, blade of nae Xo.5.
7.-—Scheuchzeria palustris L.: transverse section of limb of leaf;
7 Pit strand occupying one margin (on ne of small scale, fibrous
sheaths of bundles not separately indicated);
Fic. 8.—Alisma oi ioe ss Griseb.: blade of leaf; 2, v’, principal
veins of auricles; Xo
Fic. sc Sagane Greseit Smith.: blade of leaf; a, midrib; 6, b’, cusp
veins; Xo.5.
G. 10. fates manatorum Aschers.: transverse section of limb
of ne a
Fic. 11.—Cymodocea isoetifolia Aschers.: transverse section of limb of
ome sens indistinguishable, in smaller bundles surrounding median bundle;

ee 12.—Cymodocea nodosa Aschers.: transverse section of limb of leaf;
3,

BOTANICAL GAZETTE, LXXII PLATE I

Tetroncium
‘A-C

Sagittaria
tere

(Phyilode)

o.
Lirmnophyton

obtusifolium.

modocea
isoétifolia

ARBER on HELOBIEAE

NOTES ON NEW OR RARE SPECIES OF RUSTS
W. H. Lone

This paper describes four new species of rusts, namely, Gymno-
sporangium cupressi on Cupressus arizonica, Ravenelia subtortuosae
on Acacia subtortuosa, Ravenelia gooddingit on Acacia suffrutescens,
and Ravenelia cassiae-covesii on Cassia covesii, and gives new data
as to hosts and distribution of two other species of Ravenelia.

Gymnosporangium cupressi Long and Goodding, sp. nov.

I. Aecia unknown.

III. Telia caulicolous, from a perennial mycelium, appearing
on twigs, branches, and trunks, causing fusiform to subglobose |
swellings 1-90 cm. long, by o.5—30cm. thick, usually breaking
forth irregularly and often transversely on the smaller branches
and twigs, in irregular rows in deep longitudinal fissures of the
bark on the larger branches and trunks. When mature, telia are
more or less wedge-shaped, often irregular and somewhat crenate
at top, before gelatinization 2-10mm. broad by 4-6 mm. tall,
dark chestnut brown, becoming cinnamon brown after expansion;
teliospores 2-celled, spores with colored walls, oval to ellipsoid,
22-27 X 43-50 mw, average for ten spores 24.249 p, slightly or not
at all constricted at the septum, the two cells subequal, pedicel
cylindrical, pores two in each cell near septum, walls 2-3 yw thick;
teliospores with thin, colorless walls, oblong to narrowly ellipsoid,
not constricted at septum, 16-20 40-60 p, average for ten spores
18.653 wu, the two cells subequal, spores rounded at both ends,
pores two in each cell at the septum, walls 1-1. 5 u thick.

On Juniperaceae. Type collected on Cupressus arizonica, at Snebly Hill,
3.5 miles from Sedona, Arizona, May 26, 1920, by Leslie N. Goodding (no. 6906
Long); also collected on same host and in same locality in 1919 by Goodding
(no. 6903 Long). Collected on same host on road between Cottonwood and
Sedona, 6 miles from Sedona, May 26, 1920, by Goodding (no. 6904 Long).
This fine species of Gymnosporangium is probably generally distributed on this
host in the draws and canyons around Sedona at an elevation of about 4000 ft.
39] [Botanical Gazette, vol. 72

40 BOTANICAL GAZETTE (yoLy

Ravenelia subtortuosae, sp. nov.

o. Pycnia; none found in material at hand.

I. Aecia caulicolous, thickly scattered over hypertrophied
areas which form open witches’ brooms 1-2 cm. across. Aecia
o.2-0.3 mm. in diameter by o.8-1.2 mm. high, cylindrical, sub-
epidermal, peridium erect, margin erose and gradually weathering
away to base, cells irregularly oblong to polygonal in face view,
not overlapping, outer walls 5-6 uw thick, verrucose, inner ones
2-3 » thick, verrucose, both walls appearing as if reticulate in
certain views, side walls 2-3 u thick, transversely striate; aeciospores
irregularly oval to subglobose, angular, 13-18 18-23 pw, average
for ten spores 17X19.6 yu, walls cinnamon brown, 2-3 p thick,
minutely verrucose.

II. Uredinia amphigenous, very small, less than o.3 mm.
across, rather firm, punctiform, subepidermal, ruptured epidermis
inconspicuous; urediniospores obovate, subpyriform to oval,
15-22 X 22-30 p, average for twenty spores 17.325.7 », chestnut
brown, concolorous, or sometimes slightly darker at apex, walls
1.5-2m thick, uniform, verrucose, germ pores six, equatorial;
paraphyses very abundant, often constituting one-third to one-
half of sorus, hyphoid, incurved, chocolate brown, dense, encircling
the sorus, 10-13X40-50 mu, average for ten 10.3X43.6mu, an
occasional paraphysis clavate, nearly colorless and with a solid
stipe.
III. Telia amphigenous, oval, o.5-1 mm. across, chestnut
brown, subepidermal, ruptured epidermis inconspicuous, early
naked; paraphyses none; teliospore heads light brown, hemi-
spherical to ovoid, very irregular in shape and size, 33-100 p,
average for forty heads 52.5 uw, 3-6 spores across, marginal spores
3-16, inner spores o-12, spores in head 3-32, usual number 14-25,
smooth, outer spores 1-celled, inner ones 2-celled; cysts small,
hyaline, subappressed, ovoid, as many as the marginal spores,
cohering at sides to each other but not to stipe, swelling and bursting
in water; pedicel hyaline, compound, deciduous, short, 32-55 »
long.

On osaceae. Type for aecia collected on Acacia subtoriuosa at
Corpus Christi, Texas, May 25, 1918, by W. H. Long (no. 6506). Type for

1921] LONG—RUSTS 41

uredinia and telia collected on same host and in same locality June 25, 1920,
by Long (no. 6891); also collected at Darling, Texas, on same host June 109,
1920, by Long (no. 6892).

The aecial stage of this Ravenelia is very conspicuous, while the other two
stages are just the reverse. In fact, to find the uredinia and telia one must look
on the leaves immediately adjacent to the aecial stage. At Darling, a flag
station about 12 miles from Spofford Junction, the old witches’ brooms of this
Ravenelia were very abundant for about 1 mile along the railroad track. Often
some bushes would have from fifteen to twenty-five “brooms.” An occasional
urediniospore was found intermixed with the telia in the Darling material.

In the 1918 collection aecia and telia were found. The telia were very
rare, only a few sori to each bush. In the 1920 material collected in the same
catclaw-mesquit field, an abundance of both uredinia and telia were found
associated directly with the old witches’ brooms. The uredinia were found
on bushes growing in low damp spots with branches dense and close to the
ground. On account of the abundance of the uredinia and telia in the 1920
material this collection was made the type of these two stages.

The uredinial stage of Ravenelia subtortuosae bears a close resemblance in all
of its characters to the same stage of R. australis (as it occurs in Texas), even
to the paraphyses, but differs materially in its telia from this species. R. sub-
tortuosae is also related to R. MacOwaniana, found in south and central Africa
on Acacia horrida, but differs from this species in many important characters.

This is the only Ravenelia known to the writer reported from the Americas
that has the three stages, aecia, uredinia, and telia.

Ravenelia gooddingii, sp. nov.

c. Pycnia unknown.

II. Uredinia small, sparse (in material examined), I
scattered, subcuticular, early naked, cinnamon brown; paraphyses
very abundant, intermixed with the spores or in separate sori,
subcylindrical to narrowly clavate, a few obovate, clavate type
with thick walls and nearly solid heads, upper one-half to two-
thirds of head fulvous, balance hyaline or nearly so, stipe solid,
hyaline, 10-14 by 40-50 », obovate type thin-walled, subhyaline,

with apex sometimes slightly thickened and fulvous, 1 5-18 X
30-55 #; urediniospores broadly oval to globoid, 12-16X 16-109 »,
walls pale fulvous, thin, 1-1.5 , verruculose, pores 6-8, scattered.

III. Telia amphigenous, but mainly hypophyllous, often
Seated on pallid spots, usually found on basal half of the leaves,
Very irregular, o.s—1.5 mm. X2-4 mm. long, often confluent over
one-half to two-thirds ot the leaf, subcuticular, early naked, shining,

42 BOTANICAL GAZETTE [JULY

chocolate brown, ruptured cuticle inconspicuous; paraphyses none,
teliospore heads light chestnut brown, 5-6 cells across, 60-80 y,
average for twenty heads 70.3 uw, 8-16 marginal cells, 8-18 inner
ones, heads more or less flattened, smooth; cysts hyaline, in two
rows beneath the entire head, appressed, not cohering, oval to
obovate, easily swelling and bursting in water; pedicel short,
hyaline, deciduous.

On Mimosaceae. Type collected on Acacia suffrutescens in Baboquivari
Mountains, Arizona, October 24, 1919, by Leslie N. Goodding (no. 6983 Long).
Ravenelia cassiae-covesii Long and Goodding, sp. nov.

o. Pycnia unknown.

II. Uredinia amphigenous, scattered, round or irregular,
I-2mm. across, subcuticular, early naked, cinnamon brown,
ruptured cuticle inconspicuous; paraphyses very few, intermixed
with the spores, clavate-capitate to capitate, hyaline, 11-13 X
37-06 w, average for ten paraphyses 12.548 y, stipe solid,
hyaline, about 5 u thick, walls of heads thin, 1-1 .5 uw thick, smooth;
urediniospores broadly ellipsoid, obovate to subglobose, 15-20
17-23 w, average for forty spores 17.2X20.1y, walls cinnamon
brown, 2-2.5 » thick, verrucose-echinulate, germ pores eight, in
two irregular zones of four pores each, equidistant from the equator,
or scattered in the subglobose type.

III. Telia amphigenous and caulicolous, scattered, round,
o.5-I mm. across, subcuticular, early naked, chocolate brown,
ruptured cuticle inconspicuous; paraphyses few, similar to those
found in the uredinia; teliospore heads chocolate brown, 5-7 cells
across, 50-84 u, average for forty heads 65.3 yu, 6-14 marginal
cells, 6-20 inner ones, heads smooth or with half to two-thirds of
the cells bearing a single, wartlike, semihyaline papilla, 1-4 u long,
to each cell; cysts numerous, hyaline, globose, subappressed, in
two or three rows, beneath entire head, slowly swelling and bursting
in water; pedicel short, hyaline, deciduous.

On Caesalpiniaceae. Type collected on Cassia covesii near Tucson,
Arizona, by H. W. Thurston and Leslie N. Goodding, February 26, 1920 (no. 5537
Long); also collected on same host in Sabino Canyon, near Tucson, March 9,
1920, and January 4, 1921, by Leslie N. Goodding (nos. 6918 and 6972 Long).

1921] LONG—RUSTS 43

This species is intermediate between Ravenelia mesillana and R. papillifera.
Some of the mounts from the material collected near Tucson (no. 5537) have
nearly all of the teliospore heads smooth, while other slides from the same
locality, as well as the material collected in Sabino Canyon (no. 6918 Long) in
the foothills of the Santa Catalina Mountains, have a large number of the
heads papillate.

RAVENELIA SILIQUAE Long

This rust was collected June 1920, at San Antonio, Texas, on
the leaves, twigs, branches, and pods of Acacia farnesiana, In
many cases young pods were found with the uredinia just sporulat-
ing, while the leaves and twigs of the same tree showed old uredinia.
This proves the writer’s contention in a previous article’ that the
twig and leaf rust on this host was R. siliquae, which up to that
time had only been collected on the pods.

RAVENELIA FRAGRANS Long

A Ravenelia collected on the leaves and pods of Mimosa biunci-
fera in Arizona, by Leslie N. Goodding, was sent to the writer for
identification. A careful comparison of this material with the
type of R. fragrans shows no essential characters sufficient to
warrant making it a new species. The paraphyses in the Arizona
rust are slightly more clavate than those found in the typical
R. fragrans, while many of the teliospore heads are nearly smooth.
Each of the papillate cells bears 1-4 hyaline papillae, 1-3 u long.
The stipe is usually short, hyaline, and deciduous, but occasionally
one is found which measures up to too uw. Many telial heads of
the typical R. fragrans show cells with few and very short papillae
similar to the Arizona material.

This rust has been collected in two localities in Arizona, the
Baboquivari Mountains, October 24, 1919 (nos. 6534 and 6535
Long), and Rosemond, December 17, 1920 (no. 6969 Long). The
latter collection has a large percentage of the teliospore heads
smooth or with only an occasional head showing any papillate
cells, while the 1919 material has heads fairly typical of R. fragrans
as it occurs on Mimosa fragrans, yet the two collections are un-
questionably the same species.

* Notes on new or rare species of Ravenelia. Bot. Gaz. 64:57-69. 1917.

44 BOTANICAL GAZETTE [JULY

On a recent trip (June 1920) through Texas many areas were
revisited which in May and November of 1916 showed an abun-
dance of Ravenelia infection of many different species, yet only occa-
sionally was any Ravenelia found, although a careful search was
made on hundreds of plants which in 1916 were literally covered
with Ravenelia sori. The species of Ravenelia so abundant in 1916
were as follows: R. siderocarpi, R. papillifera, R. roemerianae,
R. mesillana, R. gracilis, R. leucaenae, R. siliquae, and Neoravenelia
holwayi; of these only R. siliquae was at all common in 1920.
This would indicate that certain years are very favorable for ‘the
propagation and dissemination of species of Ravenelia. This
fact, of course, is well known in connection with various species of
grain rusts.

OFFICE OF INVESTIGATIONS FoREST PATHOLOGY

UREAU OF PLANT INDUSTRY
ALBUQUERQUE, N.M

BRIEFER ARTICLES

HELMUT BRUCHMANN
(WITH PORTRAIT)

The name of BrRuCHMANN has become so familiar through his inde-
fatigable researches upon the prothallia of temperate species of Lyco-
podium, that some account of his life should appear in this journal,
which has so often paid the last tribute of respect to great botanists.

Hetmut BRuCHMANN was born in Pomerania, Prussia, on Novem-
ber 13, 1847, and death came suddenly at Gotha on Christmas 10920.
After the usual studies in loca
schools, he went to Jena, where
STRASBURGER was beginning his
great career as a teacher, investi-
gator, and maker of investigators.
Although I cannot find any
authoritative data, it is my recol-
lection that SrrasBuRGER himself
told me that BRUCHMANN was the
first man to take the Ph.D. degree
under his direction, and that the

highest esteem and made him his
assistant. Like STRASBURGER, he
was a master of technique, making
splendid sections before the days of
paraffin and microtomes. In 1878,
at the age of 29, he went to
Tharand to deliver a course of lectures on forestry; and a year later
was called to Gotha as teacher of mathematics and physics, and afterward
biology, in the high school. STRASBURGER offered him an “ausser-
ordentlich”’ professorship at Jena, but the stipend attached to that
position at that time was so small that he felt compelled to remain at
Gotha, with the comparatively comfortable salary of 2400 marks.
Since BRUCHMANN married Friulein Emma Jusatz in 1880, one might
45] [Botanical Gazette, vol. 72

46 BOTANICAL GAZETTE . [JULY

surmise what prompted the decision. She shared, in an unusual degree,
the cares and joys of his school life, and was intimately acquainted with
his investigations and discoveries. For thirty years he taught mathe-
matics and physics in the high school at Gotha, spending vacations and
leisure hours in his patient and thorough investigations of Lycopodium.
He was a successful teacher, reaching the highest rank in the school and
often assuming the duties of Director. His thorough knowledge of his
subject, together with a kindly, sympathetic disposition, won for him
the respect and affection of his students. In 1905 his health became
impaired, and he went to the Riviera to recuperate; but after several
months, not feeling strong enough to resume the heavy burden of
teaching, he retired upon a pension. In 1907, he visited Sicily, Tunis,
and Algiers. In his later oe Sopa eyesight made the search for
subterranean prothallia very t.

BRUCHMANN’S great sc ebacen to science was his prolonged and
successful investigation of the prothallia of the European species of
Lycopodium. When he began his studies, nothing was known of the
prothallia of temperate species except fragmentary accounts of the
aerial prothallia of L. inundatum and the subterranean prothallia of
L. annotinum. BRucHMANN succeeded in finding practically complete
series in the development of the prothallia of L. complanatum, L. anno-
tinum, L. clavatum, and L. Selago; and his excellent histological tech-
nique and his skill as an artist, together with a clear literary style,
enabled him to make an effective presentation of his researches and
conclusions. Altogether there are 17 papers, but the most important
are “Uber die Prothallien und die Keimpflanzen mehrerer Europiischer
Lycopodien,” an extensive account with 199 pages and 8 plates, which
appeared in 1898; and ‘“‘ Die Keimung der Sporen und die Entwickelung
der Prothallien von Lycopodium clavatum, L. annotinum, und L. Selago,”
which appeared in Flora in 1910.

though botanists, from the time of Hormetstrer, have tried to
germinate the spores of Lycopodium, no one but BRUCHMANN ever
succeeded with the difficult species which have subterranean prothallia.
Some may have failed by throwing away their cultures too early, for the
spores of L. Selago germinated in 3-5 years; the development of arche-
gonia and antheridia was complete only after 6-8 years; while L. clavatum
and L. annotinum were even slower, germinating after 6-7 years, and
requiring 12-15 years to produce an egg ready for fertilization. A long
series of cultures in the laboratory, with checks in the field, finally
enabled him to give a complete account of the germination of the spore,

1921] BRIEFER ARTICLES 47

development of the gametophyte, fertilization, and embryogeny.
BRUCHMANN’S success stimulated others, and while no one else found
any prothallia of European species, SPESSARD found American species,
Hottoway found prothallia of New Zealand species, while both Hotto-
way and Lawson discovered the prothallia of Tmesipteris and Psilotum.

BRUCHMANN naturally became interested in other subterranean
prothallia, and succeeded in finding prothallia of Ophioglossum vulgatum
and Botrychium Lunaria, both of which he described in his usual thorough
manner. Selaginella, since it is a lycopod, was investigated, although its
prothallia are not subterranean. He also made a study of the behavior
of the sperms of lycopods with special reference to chemotaxis.

The paper of 1898 brought widespread recognition, for in 1899 he
received the Plato Medal of the Academy of Science of Munich, and in
the following year the Demaziéres Prize of the Paris Academy of Sci-
ences, which carries with it a monetary consideration of 1500 francs.
Still later he was made an honorary member of the Naturforschende
Gesellschaft of Berne. In a letter received by the writer in 1911, how-
ever, BRUCHMANN states that, while the prizes are gratifying, his greatest
satisfaction is in the recognition his work is receiving in textbooks which
bring his results before students in the schools. His experience as a
teacher prompted him to prepare splendid sets of prothallia for labora-
tory demonstration, and these are now used in most German universities
and in many universities of other countries.

BRUCHMANN’s life and patient, persistent work prove that one who
has the interest and will to do research work can achieve a high rank
in science without the stimulus of a great university—CHARLEs J.
CHAMBERLAIN, University of Chicago.

CURRENT LITERATURE

BOOK REVIEWS
Actinomycetes
The last decade has witnessed the publication of a considerable number of

ook, in
considerable information obtained from the very extensive bibliography, of
which nearly 400 titles, Suihiggehe only a part of the total, are cited. The
largest section of the volume is devoted to a treatment of the physiological
properties of the Actinomycetes, including their reactions to nutrient an
tonic compounds, their production of odors and pigments, their enzymatic
activities, as well as a discussion of variations of different strains of Actinomyces
arising in response to changed conditions, or quite spontaneously under uni-
form conditions. The spontaneous variations with respect to chromogenesis,
sporulation, oxygen requirements, thermal relations, and production of odors,
the author regards as being in the nature of mutations. The two final sections
of the book deal with the relation of the group of organisms to animal and
human diseases, and to the diseases of higher plants. In connection with the
latter, the galls of alder roots are discussed, and a certain amount of evidence,
unfortunately not altogether conclusive, is adduced to show that the causative
organism is a species of Actinomyces.

In the Preface, the author expresses the justifiable hope that the book
may have been made to embrace both the botanical and the medical provinces
of bacteriology. He sees in the methods of medical bacteriology a more highly
developed technique, from the use of which botanical investigations might
profit. Accordingly it is not surprising that the research reported in the book,
not excluding the section on morphology, is the product of the established type
of medical bacteriological technique, although the latter thus far can hardly

method. The author concludes that septa are absent from the aerial sporu-
lating filaments, which in view of the fact that the stains used fail to show the
walls of fungi, even when these are clearly visible in unstained preparations,
need occasion no astonishment. It is to be regretted that some stain known

t LieskE, RupoLF, Morphologie und Biologie der Strahlenpilze (Actinomyceten).
8 vo. pp. ix+292. pls. 4 (colored). figs. 112. Leipzig: Gebriider Borntraeger. 1921-

1921] CURRENT LITERATURE 49

to affect wall material, as, for example, Delafield’s haemotoxylin applied for
several hours, was not tried. The process of sporulation is held to be similar
to the division of bacteria, and is generally referred to as a breaking up (“‘Zer-
fall”’) of the filaments, both aerial and submerged. It appears difficult to
understand why the irregular degenerative structures developed in submerged
material, shown in fig. 49, should be designated as spores at all. In fig. 44,
showing the development of aerial spores, sporulation is represented as involv-
ing the filament below the point of insertion of a branch, a condition which
perhaps it might be not at all easy to find realized in any preparation. A new
type of spore is also described, the “‘ Vierhyphenspore.” The development of
the latter is initiated by the serena of two short branches at right angles
near the tip of a filament. The four elements about the intercalary porti

similarity to the so-called zygospores of certain microorganisms. In spite
of the remarks of the author, the figures illustrating these structures do not
impress the reader as anything especially distinctive, and he is left to wonder
why the author saw here a character recalling the fungi, when he failed
to find fungus characteristics in the incomparably more distinctive sporogen-
ous apparatus.

In general the author seems inclined to minimize the significance of such
fungus-like characteristics as are revealed even on smear preparations stained
according to Gram. He recognizes in the Actinomycetes a group of organisms
occupying an independent position between the fungi and the bacteria, but
more closely related to bacteria, particularly to those of the acid-fast type.
As to a taxonomy of species, he offers little in the way of encouragement to
followers of precedent. The concept of species he holds to be utterly impos-
sible to apply here, all strains showing an exceptional degree of variability
under different conditions, and the presence of intergrading strains bridgin
over whatever differences may be observed between extremes. Moreover,

rob any attempt at classification of any except a slight historical interest.
Even the recognition of group species, certainly not a very happy conception
at best, is held to be futile for the same reasons. One might desire the author
to have extended his observations on the tendency toward mutation, to include
besides characteristics like color of thallus, spore color, or abundance of sporu-

behave in a consistent way, possible significant changes in structure. As the

direction of relation of the spiral sporogenous hyphae, for example, has been .
reported to be an invariable specific characteristic, it would have been inter-

esting to learn whether or not this too is subject to change by mutation.

5° BOTANICAL GAZETTE [JULY

The volume contains an abundance of illustrations, including a large
number of a of excellent quality, as well as four plates of
colored figures very well executed and reproduced.—CHARLES DRECHSLER,

ew York Botanic Contec
Rocky Mountain flowers

Since the appearance of its earlier edition in 1914, none of the less technical
books have proved as useful in becoming acquainted with the vegetation of
the Rocky Mountains as Clements’ Rocky Mountain flowers? This is due in
large measure to the drawings, and more especially to the attractive colored
plates that are reproductions of water color sketches by Mrs. CLEMENTS.
The twenty-five colored plates, together with a very simple descriptive text,
have also been issued in a smaller volume? for the use of travelers, or to be
se ede as a souvenir of vacation days.

the notable features of the larger volume are a chart exhibiting
the seuclle relationship of plant families, a key to the families, and numerous

present edition is on thinner paper, and being bound in flexible leather covers,
is very convenient as a pocket companion on mountain climbs.—GeEo. D.
FULLER.
Weeds of farm land

Miss BRENCHLEY‘ has published an interesting book on weeds of farm
land. This discussion of farm weeds should be interesting to the practical
man as affording an opportunity of comparison between the problems of the
English and the American farmer. For the latter there may be practical
hints and methods that may be applicable to his own fields. The ecologist
will find more discussion of the fundamental problems of competition and
succession than generally appears in weed manuals. The chapters on ‘‘ Vitality
of weed seeds,” ‘‘Association with soils,” ‘‘Association with crops,
‘Grass land weeds” touch upon the relationship of plants to their environ-
ment and to one another, and seek for solutions of practical problems in the
control of limiting factors. Other interesting chapters are those on “ Parasitic

“Fos ses of weeds,

35 for Polygonum aviculare, and 40 for Ranunculus acris. The illustrations
suffer by comparison with those of similar American books. —Gro. D. FULLER.

2 CLEMENTS, F. d CLEMENTS, EpitH S., Rocky Mountain flowers. 8vo.
pp. 392. pls. 47. Field ‘edtisia New York: H. W. Wilson Co. 1920

3 CLEMENTS, Epits S., sito of the mountain and plain. 8vo. pp. 79. pls. 25.
- New York: H. W. Wilson Co:

4 BRENCHLEY, WINIFRED fag ee : fads land. 12mo. viii+239. figs. 41.
London: Longmans Green & Co. 1920. :

1921] CURRENT LITERATURE 51

NOTES.F.OR STUDENTS

Taxonomic notes.—BLAKES has described a new genus (Neomillspaughia)
of Polygonaceae, based on up rsie® nner Donn. Sm., of Honduras.
It includes another species from Yuca

PENNELL® has begun the per tcirtins of a list of genera of RAFINESQUE not
recorded in Index Kewensis, although published in Autikon Botanikon. This
first instalment presents 83 genera which should be included in any complete
index. It is possible that some of these names should be in use

YUNCKER’ has published a very complete revision of Cuscuta, which is
the first attack upon this difficult genus since ENGLEMANN’S monograph of
1859. The history and morphology of the genus are given, in addition to
the taxonomic presentation. The monograph includes 54 species, 26 occurring
in the United States, 33 in Mexico, and 7 in the West Indies. Of the 54 species
and 42 varieties, 14 species and 16 varieties are new, a 32 poeres are feared
for the first time. A full bib bliogra and index of

Miss DomncE’ has published he results of her studies of South African

that region. She recognizes 24 genera, including 50 species, 28 of which are
described as new. Much the largest genus is Asterina, with 30 species, 14 of
which are new. The remaining new species are distributed among 9 genera

STANDLEY? has published a manual of the flora of Glacier National Park
especially be the benefit of the numerous visitors. The manual will be of us
also elsewhere in the mountains of Idaho, Alberta, and British Columbia, a
will be helpful in the Yellowstone National Park.

TRELEASE” has monographed the North American species of Piper belong-
ing to the section Orronta. He recognizes 12 species, describing 8 of them
as new.

The second contribution to the flora of Micronesia and Polynesia,”
under the editorship of Diets, includes 24 contributions by various investi-
gators. The most extensive one (68 pp.) is by SCHLECHTER on the Orchidaceae

5 BLAKE, S. F., Neomills paughia, a new genus of sige are with remarks on
related set. Bull, Torr. Bot. Club 48:77-88. pl. 1
EN. . W., ‘““Unrecorded”’ genera va Ramer 1. Autikon Botani-
kon 80). Dull Torr. Bot. Club 48: 89-96. 1
7,Yuncker, T. G., Revision of the North ea? and West Indian species of
Cuscuta, Univ. Til. Biol. Monographs 6:1-142. pls. 13. 1921.
*Domcr, Etaet M., South African Microthyriaceae. Trans. Roy. Soc. S.
Africa 8: 5-28: a 13-10. 1920,
* STAD Lt C., Flora of “— National Park, Montana. Contrib.
U.S. Nat. grey 22: ree. pls. 33-52.
*° TRELEASE, W., North American baie of the section Ottonia. Amer. Jour.
Bot, 8: 212-217. pis. 5-8. 1921
. seit zur Seen von Nedetien und Polynesien. II. Engler’s Bot. Jahrb.
65: 429-528. 1

52 . BOTANICAL GAZETTE [JULY

of Micronesia. He recognizes 37 genera, one of which (Rhynchophreatia) is
new, and describes 38 new species. We are only beginning to realize the
wealth of orchids in the tropics.

Hucues” has published a revision of the Australian species of Stipa,
recognizing 40 species, 17 of which are described as new. This is in striking
contrast with the 15 species recognized in the Flora Australiensis, especially
since only _s species of the 40 characterized are based on material unknown
to BEN

ae ae anent numbers of N otizblatt (Bot. Gart. Berlin-Dahlem) contain

dema (Gesneriaceae) by SCHLECHTER (7:15-18. 1920), from the East Indies
and the Philippines; Peekelia (Leguminosae) by Harms (7:26, 27. 1920),
from New Guinea; Chelyocarpus (Palmaceae) by DAMMER (7:44-5I. 1921),
from Brazil; Paraphyadanthe (Flacourtiaceae) by MILDBRAED (7:390-495.
1921), from Africa; Cheilanthopsis (Polypodiaceae) by HrzronyMus (7:406-
409. 1920), from Burma; Afrolicania (Rosaceae) by M1LpBRAED (7:483-485.
1921), from Africa; Neozenkerina (Scrophulariaceae) by MILDBRAED (7:491-
493. 1921), from Africa; Stenodrepanum (Leguminosae) by Harms (7:400-501.
1921). KRANZLIN (7:412-451. 1920) also describes 44 new species of Orchi-
daceae from Columbia, this being only the first paper of a series.—J. M. C.

of Hawaiian flora.—Because of its notable endemism, the flora of

the Hawaiian Islands has always been of fascinating interest to plant geogra-
phers. CAMPBELL’ in some recent studies of this flora regards the Hawaiian
problem as the most important distributional problem that exists anywhere.
HILLEBRAND, and perhaps most investigators, have held that the Hawaiian
flora has always been isolated, the islands having been thrown up from great
depths by volcanic action. Recent studies by Pirspry on the Hawaiian
land snails have shown noteworthy Malaysian affinities, and now CAMPBELL
finds similar evidences from the plants. The liverworts and filmy ferns in
particular are unsuited to long overseas transportation, and must have existed
in Hawaii since it was connected with other lands. The relationship of these
plants is much closer to the flora of Malaysia and Australasia than to America.
Of 40 species of pteridophytes found elsewhere, 38 are common to Australasia
or Malaysia, and only two are common to America. Fifty-one genera of
spermatophytes are common to Australasia or Malaysia, and only six are
common to America. The endemic genera are more closely related to Asia

% Hucues, D. K., A revision of the Australian species of Stipa. Kew Bull.
no. I. pp. 30. 1921.

13 CAMPBELL, D. H., The origin of the Hawaiian flora. Mem. Torr. Bot. Club
17:90-96. 1918.
, The derivation of the flora of Hawaii. Leland Stanford Junior Univ.
Publ. I. pp. 34. 1919.

1921] CURRENT LITERATURE 53

or the south Pacific than to America. The American elements that are
. present are accounted for partly through introduction by winds or migratory
birds, and partly as a residue of once more widespread forms that are now
extinct except in Hawaii and America. The absence of conifers may similarly
be explained by extinction, if they were ever present, or by the absence of
suitable soil conditions. The almost complete absence, for example, of granitic
or calcareous soils might well explain certain absences. It is noted also that
great ocean deeps separate Hawaii from America, whereas it is much shallower
between Hawaii and the Orient. It is concluded, therefore, that the Hawaiian
flora has been derived for the most part from the southern Pacific region, and
that the Hawaiian Islands are a remnant of a northeastern extension of some
large land mass, once connected closely with south Pacific lands.—H. C.
COWLES.

Studies of cambium.—BaILeEy,™ in a third paper on cambium, has
made what he calls a cytological ‘‘reconnaissance.’’ In the preceding paper,
reviewed in this journal,*5 he called attention to the size variations of cambial
initials, and to the unusual opportunity offered by the cambium for the study
of a number of fundamental cytological problems. In this preliminary study
he has reached the following conclusions. The initials of the cambium, which
may attain a length of more than gooo pw, are uninucleate, and the “working

ousand microns. The nucleo-cytoplasmic ratio may be relatively constant
in ray initials, but varies enormously in fusiform initials. All the cambium:
initials of Pinus Strobus contain the diploid number of chromosomes. Small
ray initials may contain as large chromosomes as adjacent fusiform initials
with a volume 200-1000 times as large. Fusiform initials, which are frequently
several hundred times as long as they are wide, divide longitudinally by an
extraordinary extension of the cell plate. The various types of cell plate
formation described by various cytologists are believed to be merely different
Phases or stages of a single general type of cytokinesis. These glimpses
would seem to justify the writer in his belief that the cambium well deserves
intensive cytological investigation.—J. M. C.

Economic plants of Philippines.—In an illustrated report Brown” gives
a series of descriptions of the indigenous food-producing plants of the Philip-
pines. Many will be surprised to find the statement that the edible wild
Plants of these islands are less abundant, more inaccessible, and inferior in

AtLEy, I. W., The cambium and its derivative tissues. IIT. A reconnais~
sance of cytological phenomena in the cambium. Amer. Jour. Bot. 7:417-434.
bls. 26-29. 1920.

*§ Bot. Gaz. 71:408. 1921.
‘6 Brown, Wa. H., Wild food plants of the Philippines. Phil. Dept. Agric. and
Nat. Res., it For. Bull, 21:1-165. figs. 81. 1920.

54 BOTANICAL GAZETTE [JULY

quality to those found in the United States. There are certain notable
exceptions, however, as the pili nut (Canarium luzonicum), which is abundant

and superior to the almond in quality, and the wild mango (Mangifera caesia),
with its delicious flavor. Nuts, seeds, fleshy fruits, buds, leaves, roots, and
tubers are included in the list, and the drawings and photographs used to
represent them are of excellent quality.

A companion report by West and Brown” deals with native resins and
oil-producing plants, which are rather numerous. One difficulty in the
utilization of the resins of many of the trees is to be found in the large number
of species found in any particular area, making the number of individuals of
any one species in any locality rather small. Several of the oil-producing
plants give promise of good results under cultivation. In this report, <
the illustrations and descriptions give much botanical information.—GEoO
FULLER.

Ecological research.—In his report of the work of the Carnegie Institu-
tion for 1920, Director MacDoucaL# indicates the lines of research being fol-

MacDoveat, and his results seem to show that species may be the more readily
transferred from cool regions to warm, from montane regions to maritime, and
from regions of climatic extremes to those of equable climates than the reverse.
SHREVE reports progress in a soil temperature survey of the United States and
Canada, in his investigations of the arid Avea Valley, and in his explorations of
the Santa Lucia Mountains. Mrs. SHREVE has studied seasonal changes in the
transpiration of Encelia farinosa, and VINSON and GRIFFIN have investigated
the changing composition of Salton Sea water. The strand vegetation near
Monterey, California, has been examined by Cooper, and stations and quad-
rats established for more exact studies of the associations and their controlling
factors. Evaporation rates on the Monterey peninsula are decidedly less than
in the oak and chaparral region east of Monterey, and this may account for
the pine forests covering the former area.—GEo. D. FULLER.

Calcicoles.—In a discussion of plants found on soils supposed to be cal-
careous, SALISBURY” makes it clear that the problem of the limitation of the

West, A. P., and Brown, W. H., Philippine resins, gums, seed oils, and essential
eils. Phil. Dept. Agric. and Nat. Res., Bur. For. Bull. 20: 1-230. figs. 73. 1920.

% MacDoucat, D. T., ta ora of botanical research. Carn. Inst. Wash.
Year Book for 1920. 19: mes

19 SaLisBuRY, E. J., The See of the calcicolous habit. Jour. Ecol. 8: 202-
215. 1920.

1921] CURRENT LITERATURE 55

species to this substratum is by no means a simple one. In the first place,
there is great need of more accurate data regarding the exact distribution of
such “‘calcicoles’’ and of the exact nature and chemical reaction of the soils
in which they are growing. As an example of the need of such precautions
it is shown that “‘calcifuges’ ? may and do occur on soils usually considered
calcareous, but on account of leaching there is really no calcium in the soi
in contact with the plant during its youthful and critical stages. It is further
shown that complexity is added to the problem by the secondary characters
usually accompanying calcareous soils, such as their comparative freedom
from toxic products of decay, their usually low water-holding capacity, the more
abundant development of their soil fauna, and the influence of calcium upon
the absorption of other elements such as potassium.

The entire discussion is a thoughtful consideration of the various aspects
of the problems concerned, and with the rather extensive bibliography is a
good survey of the entire field —Gro. D. FULLER.

Forest trees of Hokkaido, Japan.—Recognizing in the rapid changes
taking place in Hokkaido a menace to the existence of its forests and its timber
supplies, the government has appreciated the importance of a scientific know]-
edge of its trees as a basis for increased attention to forestry. As a result of
the investigations thus prompted, there is being issued a most attractive set
of beautifully colored plates, accompanied by descriptive text in Japanese
and English.» The plates depict the foliage, flowers, fruit, buds, seeds, and
seedling stages, one plate being devoted to each species. The three fascicles
now issued include Taxus cuspidata, Abies sachalinensis, A. Mayriana, A. Wil-
sonti, Picea Glehni, P. jezoensis, Larix dahurica, Pinus pentaphylla, P. pumila,
and Thujopsis dolabrata. The finished work will comprise not less than
85 species.—Gro. D. FULLER

Notes on Conifers.—Two botanical memoirs by CuurcH* will be of
interest to teachers of botany, especially those most concerned with mor-
phology and forestry. These papers are used at Oxford in class work, making
it unnecessary for ii students to take lecture notes, and, at the same time,
furnishing v very t tory work. Both papers lay empha-

sis upon features which can be seen without a compound microscope, although
the microscope is used for some details of the life history. The first paper is

2 Mrvaze, Kinco, and Kuno, YusHun, Icones of the essential forest trees
of Hokkaido. 10.515 inches. Sapporo. Pub. by the Hokkaido government.
Fasc. 1.1-15. pls 1-4. 1920; Fasc. 2.16-26. pls. 5-7. 1920; Fasc. 3.27-37- pls. 8-10
1921.

** Cuurcu, A. H., Came notes on Conifers. Botanical Memoirs. no. 8.
Oxford University Press. PP. 32. :
, Form factors in Cnathecs Botanical Memoirs. no. 9. Oxford Uni-

versity Press, pp. 28.

56 BOTANICAL GAZETTE [JULY

more elementary and would be used by students who have had only a general
course in botany. The second paper is more advanced and could be appreci-
ated only by students who have some previous knowledge of Gymnosperms.—
C. J. CHAMBERLAIN.

Indian Botanical Society.—A notable botanical movement in India is the
recent organization of “The Indian Botanical Society,’ whose aims, consti-
tution, and list of members have just been published for distribution. It is
stated briefly to be ‘‘a society for uniting the botanists and promoting the
botanical interests of India.’ A more detailed statement of aims is to improve
the quality and content of botanical instruction, to encourage and promote
research, to provide a central exchange, and to make available to members
the scattered and insufficient botanical literature that reaches India. The
president is WINFIELD DuDGEON of Ewing Christian College, Allahabad City,
and the other officers, three of whom are Indians, represent other institutions.
The society begins with 85 members, representing 10 provinces of India.—
i ek

African veld.—In a description of the vegetation of South Africa, PoLE-
Evans” uses the term “‘veld” to include all the native vegetation ranging
from a rich forest on the southeastern coast to a desert in the interior Karroo.
He covers the ground as in a former article noted in this journal,3 but with
more emphasis on the economic resources and possibilities of each region.
The nineteen divisions into which he divides the region possess rainfalls ran-
ging from zero to 70 inches per annum, while the diversity in vegetation is
correspondingly great. This diversity is made evident by excellent illustra-
tions, as well as by lists of species and the enumeration of resources of timber,

bers, gums, and fruits in addition to the forage plants ——Gro. D. FULLER.

Embryogeny.—SovuEGES,* in continuation of his numerous detailed studies
of the embryogeny of various families of seed plants, has reported his results
' for Urtica pilulifera, Senecio vulgaris, four species of Rumex, and a species of

Rheum. The details are too numerous to recite, but the excellent figures
present the facts clearly for those using such data.—J. M. C

22 PoLE-EVANs, Fe ts fog veld: its resources and dangers. So. African Jour.
Sci. 17: 1-34. figs

23 Bor. Gaz. hai ‘os

, RENE M., Embryogénie 0 kip reales fons de l’embryon

chez,l’Urtica pilulifera. Compt. t. Rend. 1 . 21.1920

———, Emb ce rah —. = développement
de l’embryon chez le Senecio vulgaris. Compt. Rend. 1

———, Embryogénie des Composées. Les ape. es Me ues de
VYembryon ~ le Senecio vulgaris. Compt. Rend. 171:1920,

——, Te sur l’embryogénie des Polygonacées. Bull. Soc. Bot. France
IV. 20: ae pervs ;

VOLUME LXXII NUMBER 2

y te @ oS
DOTANIC AL GAZE Te

* AUGUST 1921

PEAT DEPOSITS AND THEIR EVIDENCE OF
CLIMATIC CHANGES
ALFRED P. DACHNOWSKI

(WITH TWELVE FIGURES)

The time in which the various peat deposits of the United States
were formed can be determined only from a joint consideration of
glacial geology, climate, and plant remains. These reflect the
relations between a deposit of peat materials and its environment.
To attempt a correlation of this kind on a chronological basis,
however, has many difficulties, which investigators in the respective
sciences appreciate.

The essential nature of stratigraphic differences in peat deposits
_is indicated by the nature of the plant remains and the order in
which layers of peat material lie upon one another, that is, by the
sequence of the vegetation units which at one time formed layers
of plant remains in the deposit. As to the tectonic order of the
layers or series of layers of material composing a peat deposit,
little need be said at this time. From the standpoint of stratig-
raphy the condition of the initial area in which a pioneer plant
population established itself is the critical factor of greatest im-
portance, so far as the beginning of the course of development is
concerned. The sequence of the development may become changed
anywhere in the course, either by changes in environmental factors
or in plant population. These changes are all recorded within the
deposit. In the vast majority of peat deposits the beginning of

58 BOTANICAL GAZETTE [AUGUST

development and the succession of peat materials have to do with
the factor of water content in the original area. Usually the
quantity of water is more frequently concerned than its salinity,
acidity, or alkalinity. The initial water relation, by its selective
action, determines not only the characters of the life forms which
establish themselves as the pioneer population, but also the number
of layers possible and the order of their sequence.

In a preceding paper (7) it was proposed to classify peat deposits
of whatever nature into two great primary groups, the group of
water-laid peat deposits and the group of land-laid peat deposits,
in accordance as they have arisen in water or on partly drained
but relatively moist initial areas. In the water-laid peat deposits
the bottom layers consist of materials which accumulate only in
standing water. They contain the remains of planktonic organisms
and macerated material from plants more or less submerged or
floating, or which occupied the margins of the basin. Subdivisions
- of this group are given in the section which follows. In the land-
laid group of peat deposits the origin is indicated in the mineral
substratum by the vertical roots of plants which at one time
occupied the area, as a well defined plant population or vegetation
unit. The general stratigraphic subdivisions in this group are
indicated by the order in which the vegetation units invaded and
occupied the land area. With respect to the layers of peat material
formed by them the order may be (1) progressive, that is, beginning
with some member of the marsh group of peat materials until the —
deciduous or coniferous forest climax of the region is reached;
(2) stabilized, that is, it may begin and continue in a stable forest
climax; or (3) the order may indicate the conversion of the basal
forest climax into marsh and finally to open water conditions by
the influence of various environmental causes. This distinction
between the two primary groups of peat deposits is clear cut, and
is readily made in field work. The only possible difficulty arises
when the plant remains have been redeposited or partially removed
by any later action, such as erosion. Even secondary disturbances
of this nature, however, do not invalidate the importance of the
stratigraphic viewpoint. Its significance for correlation studies
has been sufficiently dwelt upon elsewhere (6).

1921] DACHNOWSKI—PEAT DEPOSITS 59

The following pki deposits are representative of the subdivisions
in the land-laid group, and will be reported in another paper:
1. The New Haven Marsh near Plymouth, Ohio (glacial Lake
Maumee type); the peat deposit southwest of Rome, New York
(glacial Lake Iroquois type); and the Algoma Muskeag near
Roseau, Minnesota (glacial Lake Agassiz type). 2. The Dismal
Swamp west of Norfolk, Virginia (Pamlico coastal terrace type).
3. The Kankakee Marsh, between South Bend and Crumstown,
Indiana (in the Bloomington morainic system). It will be noted
that peat deposits. are regarded here in their relative space and
time dimensions.

In regard to the stratigraphic units of peat deposits, reference
may be made to Bulletin 802 (5) and left with this passing sug-
gestion. Whatever system of classification of peat materials may
be adopted, it will be found that for several reasons it cannot be
carried uniformly and with constant value over so broad a territory
as discussed here. The main difficulty arises from the unlike
development of the vegetation unit which forms the layer of
peat, and from modifications of the successional series in diverse
geographic regions. Insensible gradations or phases due to varia-
tions in composition of plant remains set a limit to the most
refined botanical division of peat materials that can be recog-
nized.

Investigators approaching peat-land problems for the first
time are apt to be influenced by the idea of permanence and fixity
of specific limits. In a large measure this may be accounted for
by the fact that the very recognition of such a thing as a type of
peat material carries with it the impression of an entity, and that,
if these characteristics are modified or supplanted by others, the
unit in question no longer belongs to that type. The degree of
individual difference admissible within a type is a matter of indi-
vidual judgment. Variations exist within specific limits, but
what these limits are is still a matter of diverse and constantly
changing opinion, until these gradations and phases are measurably
well established. No evidence of this sort of peat type limita-
tion is available as yet, but the detailed application of ecological
and instrumental methods strengthens the conviction that the

60 - BOTANICAL GAZETTE [AUGUST

arrangement and naming of the different types of peat are merely
matters of practice in field work.

In this paper it is not the intention to furnish the numerous
details necessary to a knowledge of the different types of peat
material, nor is it necessary to review from a voluminous European
literature all the widely scattered observations on types of peat
and their variations. So far as observations indicate, variations
of stratigraphic units represent but a temporary condition. The
structural development of a peat deposit is characterized by the
regular occurrence of several types of peat material in many
different forms and phases, such as differences in the growth and
evolution of vegetation units. These phases are connected by
more or less constant field relations. Unquestionably many so-
called ecological stages represent merely fragments in the develop-
ment of a peat deposit, reactions of one plant population upon
another. On the other hand, well distinguished types of peat
material will not only keep their position, but will receive a much
more nearly complete and sharper definition than they have at
present. It is for these reasons that only major divisions of plant
remains are distinguished in the following discussion. They have
been adopted also wherever the differences of information are
sufficient to occasion difficulty in applying a uniform classification
of types of peat. The list has been summarized (5), and has been
utilized with the addition of two new marsh types of peat found
in Florida and California respectively, to facilitate reference be-
tween the cross-sections of peat deposits and the text.

The conventional signs represented in the graphic illustrations
of the profile sections described in large part are adjusted to the
standard of European workers and the requirements of cartography.
The departures which arise (partially from thé inaptness of the
material as a type of peat) have been stated in the legend, and
in connection with each layer described in the text. Beds or
strata which are not sharply defined in a deposit may be recognized
by the dotted boundary lines.

It is to the interest of a group of scientific and industrial workers
that coordinated efforts should be brought to the solution of
peat-land problems. ‘To those who desire general field information

1921] DACHNOWSKI—PEAT DEPOSITS 61

regarding types of plant remains the following are some of the
localities near which layers of peat material are displayed in typical
orm at or somewhat below the surface of the peat deposit. Ma-
cerated and colloidal types in Cedar Lake near Fremont, Indiana
(fig. 2); Phragmites type and Carex type near reservoir on New
Haven Marsh, Plymouth, Ohio; Hypnum type in Algoma Muskeag
near Roseau, Minnesota, and in basal layer of the peat deposit
exposed along the barge canal and James Street bridge below
Rome, New York; Cladium type in the Florida Everglades at
Okelanta and vicinity; Scirpus type at Middle River and near
Wintersburg, California; Sphagnum type on Cranberry Island at
Buckeye Lake, Ohio (fig. 3), and in peat deposits west of Arlberg,
Minnesota; coniferous forest types near Kent, Ohio (fig. 10), and
north of Kelliher and Warroad, Minnesota; mixed deciduous
forest litter type in Dismal Swamp, Virginia, in basal forest of
Kankakee Marsh near Crumstown and South Bend, Indiana, and
in middle and upper forest beds of the peat deposit southwest of
Rome, New York; deciduous forest type near Mantua, Ohio
(fig. 12). More specific information concerning peat materials
and their agricultural and industrial value may be obtained in
Bulletin 802 (5).

I. Water-laid peat deposits.

The chief feature of the group of water-laid peat deposits is
the presence of aquatic types of peat material as the initial layer.
The deposits may vary widely in the number and character of the
initial stages, and the number of stages may range from one layer
to several in the deeper deposits, including secondary phases.
From the manner in which the peat materials are laid down in
standing or in flowing water, in fresh or in brackish and saline
water, the successive layers as a rule furnish conclusive evidence
of three major series of stratigraphic differences. The group of
water-laid peat deposits may be subdivided into (1) basin deposits
with standing water level, such as lake and pond deposits, and
(2) deposits in depressions with fluctuating water level, the river
and overflow deposits, of which the Florida Everglades and their
alternation of fibrous and macerated layers of peat material are

62 BOTANICAL GAZETTE [AUGUST

a notable example. The coastal river and estuarine peat-lands
merge into the (3) marine deposits such as tidal marsh and
mangrove swamps. A discussion of the brackish and salt water
deposits is reserved for a future paper. 3

Ev IDENCE OF CLIMATIC CHANGES

It might seem that the water-laid group of peat deposits could
not offer reliable and direct criteria for evaluating age or time
correlations, since water in basins constitutes a fairly uniform
environment. There is continuity in the sequence of strata of
plant remains, but macerated and more or less structureless layers
of peat material bear no fixed relation to the plant populations
which succeeded each other in the development of the deposit.
The organic fragments are derived from many sources, and are
in large part from suspended débris. Nevertheless, inferential
evidence of past vegetation units and climatic changes may occur
in abundance. .

The evidence for age and for climatic correlations is of several
kinds, of which one form is represented in the scattering and mixing
of leaves, pollen, and seeds blown into a peat deposit or washed
in from adjacent land vegetation units. The latest substantial
comparison between plant remains (such as the pollen of conifers)
in layers of peat material and the changes i in climate and in the
composition of land-plant communities is the quantitative method
employed by von Post (24).

A second kind of evidence of climatic changes found in peat
deposits consists of dark colored, partly macerated, and fibrous layers
of material alternating with predominantly finely fibrous, coarsely
fibrous, or woody plant remains. The close association of this
kind of stratification in practically all sorts of peat deposits, without
any close relation to topography or the influence of animal agencies,
appears to signify alternating wet and dry environmental condi-
tions. Quite frequently the dark colored, partly fibrous layer of
peat material is referred to by American writers as “well decom-
posed peat.’’ Although it bears a striking superficial resemblance
to a finer texture, similar to weathered surface material, a layer of
this character does not imply conditions of aeration, or of warmth

1921] DACHNOWSKI—PEAT DEPOSITS 63

and dryness by means of which decomposition and oxidation are

accomplished. The layer represents rather the open scattered
growth of plant populations, such as sedges, reeds, rushes, and
brown mosses. The “well decomposed” débris as a rule is the
intermixture of macerated material from aquatic and amphibious
plants. The presence of diatoms, sponge spicules, shells, silt, and
windblown material of various kinds usually shows that the chief
condition for its formation is a higher water level. So long as the
water table continues at a higher level, the fibrous type of peat
tends to retain the aquatic admixture; the disappearance of the
macerated débris would indicate conditions of ground water below
the surface soil; and an alternating sequence of these layers would
mark a period of climatic pulsation, of alternating wet and dry
conditions. In carrying out quantitative determinations on sam-
ples of “well or partly decomposed” peat materials, the use of
the colloidal suspension test and the methods of K6nic (15),
MELIN and Op£EN (22), and KEPPELER (13) are only partly ade-
quate. The possibility of obtaining erroneous results must be
checked by a preliminary microscopic examination of the organic
material, and by a consideration of its position in the profile struc-
ture of the deposit.

Some European workers are strongly of the opinion that a
climatic break in the waning portion of the glacial period is indicated
by the remains of forests found buried in stratified peat deposits,
and by the “‘horizon”’ layer between the lower, in part disintegrated,
and the upper, relatively more recent sphagnum peat of certain
high moors. The materials are believed to be evidence showing
there has not been merely a steady amelioration of climate since
the last ice movement, but rather a fluctuation between periods
of dry and wet climatic conditions. The dissent from this inter-
pretation on the part of other investigators does not appear to be
chiefly a matter of the proper terms to apply to types of peat and
their variations, These layers of “horizon” peat and of buried
forest, however, constitute more properly supra-aquatic types of
plant remains, and on that account their consideration is deferred
to the section dealing with the general stratigraphic features of
lacustrine deposits of peat. In this connection it is suggested that

64 BOTANICAL GAZETTE [AUGUST

superimposed layers of colloidal type of peat material in certain
deposits probably indicate another kind of evidence of former
relatively dry and warm climatic conditions.

A third form of evidence which may aid in the interpretation
of the age of deposits and the climate which characterized their
development consists in the seams of clay found between layers of
peat material. These are often found with an admixture of organic
matter, but rarely laminated in a manner similar to the seasonally
laminated glacial clays described by DE GEER (10) and SAURAMO
(32). Interstitial clay seams appear to be coincident with the
earlier portion of the Wisconsin group of moraines. They have
been noted especially in connection with peat deposits located in
areas where readvances of the ice sheet are displayed in the drift.
The investigations, however, are not sufficiently extensive to show
whether the clay seams would be prominent also in morainal
systems which are free from a surface cover of wind-blown loess.

The fourth form of evidence which seems very promising is that
of the marked structural differences found in certain peat deposits
over a wide extent of country in which a series of moraine systems
is the time factor of distinction (fig.1). Leverett (19) has shown
that the Wisconsin drift displays moraines which are distinctive
and well preserved. They are more or less concentrated in groups
which permit of much greater detail of correlation than is possible
in connection with the glacial stages in Europe (12, 18, 27).

The morainic systems of the Wisconsin ice sheet mark halting
places in the recession of the ice front. They obviously represent
climatic pulsations, for the evidence seems clear that the ice sheet
was subject to increase or decrease in response to climatic variations.
Periods of warmth during which the ice sheet retreated somewhat
rapidly, leaving nearly level tracts of drift, must have alternated
with periods in which the climate ceased to be mild, and either
remained nearly uniformly colder for a time or else reverted toward
the conditions which induce glaciation.

For the study of past climatic changes and plant migration
since the culmination of the last stage of glaciation, a comparison
of the stratigraphic features of peat deposits should bring out
evidence of great value. By actual test borings of peat deposits

1921] DACHNOWSKI—PEAT DEPOSITS 65

within the area of the several great morainic systems, such as the
Shelbyville, the Bloomington, the Valparaiso-Kalamazoo-Missis-
sinawa, the Lake Border—Defiance, and the Port Huron, it should

od 88° 86° 4° 82° oo” i. ee
~

E Up >
af S fa

Fic. 1.—Diagrammatic outliné of Wisconsin ice ponte we several successive
positions latter LEVERETT and TAYLor 1g with slight : lines of direction
of ice movement grees from original map, and names of a few localities with peat
deposits added by write

be possible to sum up the whole series of climatic changes which
have taken place while the ice field receded, and to estimate the
length of time for every single glacial substage. Primarily because

66 BOTANICAL GAZETTE [AUGUST

of their greater age, the deposits of the earlier morainic fields
constitute climatic indicators of the greatest interest, and they
should not only furnish additional data, but also serve as a check
upon any evidence which the peat deposits in the later morainic
areas may contribute.

The material here presented is only of preliminary import. It
has emerged in the field work of the past seven years, and hence
a definite correlation is impossible as yet, partly because too little
is known of the extent and intensity of the changes. The chief
difficulty, however, lies in the fact that much along the line of
detailed field and laboratory studies has still to be accumulated.
The conclusion is irresistible, however, that when the field is
traversed the peat deposits will be found to furnish a new great
record of the vegetational and climatic oo: of the country
since Pleistocene times.

GENERAL STRATIGRAPHIC FEATURES IN WATER-LAID
PEAT DEPOSITS

The question of the formation of lacustrine peat deposits has
‘produced a copious literature in many countries, but there is still
a dearth of observational evidence on their actual structural origin.
Hardly a case exists of an intensive study in which conclusive proof
is available showing the types of peat material in process of forma-
tion. This does not mean that the process may not be as is gener-
ally assumed, but it does indicate that even a well-nigh universal
opinion may yet constitute merely an excellent working hypothesis.
It can be accepted definitely only after more rigorous tests and
extensive field work disclose a clearly defined basis. This account
merely serves to emphasize what may be regarded as a general
view of the development and structure of lacustrine peat deposits.
Although this has been discussed at some length.in various papers
already published, a brief outline is presented here in order to
connect it with the profile sections of the peat deposits on which
these discussions have a bearing. The cross-sections which follow
have been selected from American and European peat deposits
largely on account of their stratigraphic relationship. They visu-
alize the succession of strata in water-laid deposits, and illus-

1921] DACHNOWSKI—PEAT DEPOSITS 67

trate the general development which had come to the final stage
possible under the limits of the particular field conditions of
different countries.

In a consideration OF =]
of basined deposits or E | Carex calama-
moors it should be a go Somes peat
kept in mind that de-
pressions with stand-
eran eee i ee Le
ing water originate in | peat (in part
a great variety of peepee rh gprs nese aacpled taal
ways (30). Of chief
importance, however, Colloidal
is the fact that the 5-®
initial types of peat
material are primarily oe ge ag iam oe Sogn
water-laid. They are [=== === ae cerated
mipely: confined toovs (sae Pet
the lower or deeper 30 ES
parts of the depres- © SHSSDSSS SSO STI
sion, where planktonic
organisms, together RE EEE sae
with comminuted Pe ena ere gescieiarpeononge
fragments and other —r
plant remains from
both land and aquatic
vegetation, sink to the Clayey phase
ottom. A complete
filling of lake and Sandy phase
pond basins does not
Sand

usually occur by the
formati i

t —e er 2.—Cross-section of soundings in “Cedar
ypesof peat material. Lake” peat deposit near Fremont, Steuben County,
The peat-land near Indiana

Fremont, Indiana

(fig. 2), represents a relatively rare deposit of peat. The level
where the higher plant communities can gain a foothold or succeed
one another depends upon the ability of the plants to form a

68 BOTANICAL GAZETTE [AUGUST

floating mat. The thickness of purely allochthonous (transported
to the place of occurrence) layers of peat, therefore, is far less
extensive than might be assumed, partly also because submerged
and amphibious plant populations can take root in depths varying
from ro to 15 feet (3-4.5 m.) and accumulate as peat in situ. The
macerated type of peat is nevertheless preeminent, arid it varies
least in character under conditions which give rise to water colored
brown from the presence of suspended and dissolved organic débris.
On account of the decrease in light and heat available, and the
consequent absence of submersed plant communities, the filling
of the depression is chiefly from vegetation units bordering the
basin. The colloidal and doppleritic types of peat, on the other
hand, make clear another set of conditions; they appear to indicate
a higher calcium carbonate content of the waters at the time of
their formation, and stimulating environmental conditions of tem-
perature and light, in which the growth of aquatic vegetation
units and planktonic organisms probably reached unprecedented
proportions. There are reasons for concluding that the colloidal
and doppleritic types of peat may represent another kind of evidence
of climatic fluctuations. In the deposit near Fremont, Indiana
(fig. 2), for example, colloidal material alternates with layers of
macerated and “acidic” plant remains. The formation of colloidal
material, therefore, may correspond in time with conditions of
drought, when the lake or pond waters were concentrated by evapo-
ration and became alkaline as concentration progressed. It is quite
probable that the finer calcareous material in the drift had been
removed by leaching, and produced variations in the chemical
composition of the lake and ground waters. The calcium carbonate
content when separating in the open water in a finely divided state
must have become mingled with the plant débris so as to form a
flocculation product and in places an end product of plant disinte-
gration combined with lime. The climatic changes which brought
about this condition may not have been sudden or excessive, but
probably were oscillations of moderate intensity, whose cumulative
effects were felt during that period of time.

The rate of building up a peat deposit in lakes or ponds appears
to increase considerably as a plant population such as that formed
by sedges pushes out from the shores, becomes nearly or quite

1921]

closed and exclusive, and
forms a floating mat. Essen-
tially this mat is fibrous and
contains macerated débris.
When only partially at-
tached at the sides or
beneath the surface, and if
for any cause there is a con-
siderable rise of the water
surface, the mat floats upon
a pocket of water (fig. 3).
Later the mat is compact
enough to bear the weight
of shrubs, trees, and even of
dense forests. When, how-
ever, the weight of the float-
ing mat becomes too great,
it either breaks or sinks with
its load. Layers of marsh,
shrub, or forest types of
peat material then occur,
interpolated between layers
of aquatic plant remains.
Thus an inverted order of
Superposition results. It
would obviously be a fallacy
to correlate stratification, of
this kind with alternating
dry and wet climatic periods.
Neither would the profile
indicate conversion such as
may result from artificial
causes which obstruct
drainage, nor a backward
sequence of plant commu-
nities, that is, retrogression.

‘It is apparent also that in
the gradual closing of basined

DACHNOWSKI—PEAT DEPOSITS

f)-
dl

Sphagnum
peat

Carex

Feet in depth

peaticsese

Ste ae ae —

fra? Ree oe larare O siacerarergne RS ay

2 Ben 8: OC 2 xX re rata XX Cx SS
——

— -— ar

—
——— ee
—_—

Fic. 3.—Profile section of ‘‘Cranberry
Island” peat deposit at Bucke oo, _ Licking
County, oe Arcade 892 feet a.t.; location
of soundin
(see fig. 4, Bor. Gaz. a dike
was but in 1838 which aft, the ae level
8 fee

ge seat

ae ae
~~ Scheuchzeria-
hagnum

Boundary horizon
calluna-eriophorum
peat

N
K
N
N
N

ALSGOTROPHIC
PED T FORMATION

(
») I

YY) IIDAK

Older sphagnum
peat

(COCO

Scheuchzeri
carex-sphagnum,
eriophorum peat

Pinus and betula
forest peat

le yyy)

)))

| Alnus peat

Phragmites peat

* Rasmus peat

55
Pesos atote estates
iso Pesteenroeere KS ‘
sesete re seese} Colloidal peat
eas BRS eotetatecetee 25
necatatetatetetonecete fot
statetetasetatats

2,0 ,9 0 .%.@
seis nenennes

==—~===-| Clayey phase
‘| Diluvial bottom

Fic. 4.—Generalized section through North
German peat deposit 7 m. (22 feet) in thickness,
showing succession of layers of peat sinthelal:
after WEBER (36).

BOTANICAL GAZETTE

[AUGUST

water by vegetation units
there is not only a grad-
ual decrease in available
ground water, but in min-
eral food constituents as
well. The earlier plant
communities and _ those
which occupy a position
near the margin of the
asin derive their salts
from the water or from the
soil on which they grow.
For the succeeding units
this becomes less and less
in amount. When com-
pletely filled, the inward
sequence of peat material
(the horizontal section)
and the upward sequence
or vertical section of plant
remains may show char-
acteristics successively dis-
tinct in content of mineral
matter, such as lime, and
of water incident to the
increase of thickness of
peat. The difference be-
tween the total mineral
content of a peat deposit
and an adjoining lake has
been shown for Cranberry
Island at Buckeye Lake,
Ohio (3). The term eu-
trophic is used by WEBER
(36) for types of peat formed
in water rich in mineral
nutrients, and oligotrophic

1921] DACHNOWSKI—PEAT DEPOSITS 71

for types with water poor in saline food constituents, while meso-
trophic is applied to the peat materials in the intermediate stage

g. 4).
Another significant difference lies in the fact that the final
climatic vegetation unit of a particular region, for example, a de-
ciduous forest (fig. 12) or a coniferous forest, is also the climax
stage of the sequence of peat materials in lacustrine deposits.
Successionally the sphagnum and heath shrub vegetation units
appear to be a later stage in the structural development of peat
deposits. Their superposition upon marsh or forest types of plant
remains, however, is not to be considered an anomaly or an excep-
tion. The sequence stands in the same causal relation to develop-
ment as is the case with other vegetation units. Here, however,
it is connected with the fact that the ground waters of peat deposits
in this stage of development are deficient in mineral salts, and that
bog mosses absorb and retain large quantities of rain water on
account of their anatomical structure. Sphagnum peat materials
reach their greatest thickness in cool humid locations with abundant
rainfall, and contain as a rule only little mineral matter. Theo-
retically the sphagnum stage in the structural development of a
peat deposit should be succeeded by shrub, and finally by forest
stages in the course of time. Actually this does not appear to
take place, unless the layer of moss peat has been reduced in volume
by disintegrating processes, and as a result becomes more permeable
to ground waters. In the present state of our knowledge it is
impossible to be certain that disintegration can occur without a
change in climate. Thus the “horizon peat” between the lower
(older) and the relatively more recent (upper) sphagnum peat in
northern Germany (fig. 4) is regarded by WEBER (36) as due to
a climatic change unfavorable for the growth of sphagnum mosses.
Von Post (23) has corroborated this view by his work in Sweden,
VAN BarEN (1) confirmed it for some of the peat deposits of the
Netherlands, and ZAILER (37) verified it for the peat deposits of the
Enns Valley in the Austrian Alps. The layer is assumed to indicate
a long interruption of peat formation, during which the high moor
was covered with Eriophorum and Calluna, and sometimes with
forest. WEBER and von Post conclude that the horizon peat

72 BOTANICAL GAZETTE
Feet in
depth
Hypnum-
carex
peat
Carex
10
Macerated
peat

Fic. 5.—Cross-section of peat deposit near Sarna
Station, Volinsk Province, Russia; after Doctu-
ROWSKI (8).

[aucusT

must have been built
about the end of the
later Stone Age and
after the Litorina
subsidence (33, 34)-
On the other hand,
RAMANN (28) and
Potonié (25) con-
cluded that the as-
sumption of a change
of climate is unneces-
sary, and that the
horizon layer is deter-
mined by the physical
characteristics of this
type of peat. The
double character of
the sphagnum layer is
accounted for by the
gradual diminution of
the water raised by
capillarity during dry
seasons in certain
thicknesses of the
peat material. “Die
Sphagneen kénnen
dann nicht mehr aus
den tieferen Schichten
mit Wasser versorgt
werden und sind auf
jene Mengen ange-
wiesen, die sie in ihrer
wachsenden Schicht
festzuhalten ver-
mogen. Es werden

handen sein, eine
tiefliegende und die

1921] - DACHNOWSKI—PEAT DEPOSITS 73

Oberschicht, beide durch trockneren Torf getrennt.”’ LEsQUEREUX
(16) also believed that peat deposits when checked by dryness form

a parting layer between
an old and a new bed of

peat which takes on the

shape of a dry layer.
With increasing
study of the structural
features of American
peat deposits, correla-
tions of various kinds
will undoubtedly de-
mand more considera-
tion and will assume
their basic importance.
At present, however,: it
appears to be well
founded to regard ap-
parent structural climax
layers as depending
mainly upon the con-
tinuation of certain re-
gional field conditions.
It has already been
suggested that the struc-
tural development of a
peat deposit may fail to
terminate on account of
unfavorable local field
conditions, and that
various factors may in-
hibit a further develop-
ment or may produce
secondary stratigraphic
features of varying
character. There ap-
pears to be little doubt,
however, that whenever

Feet in
depth

ee Nr Se
wt ae 8 a
ae a ee ee
ee ae eo

Carex peat

VY VV Y YY

v
a
ie

Shrub peat

pusllicnssnstiontiiesmtindinnastintionmedtnetiemnednedie |
fe a ee

Ce a ee Ate
peat with
carex

| ~Macerated
peat with

ff ipnupethoas ngage clogs ngs: caamrertio agente mn cladium

eee Ce

E : = : Marly

phase
Sand

Fic a Prothe section of the Pay peat petty
Scone. Sweden; after SANDEGREN (31

BOTANICAL GAZETTE

[AUGUST

the movement of plant populations continues, either through a

further change in habitat or in the development of new plant com-

munities, the climatic
vegetation unit is

Feet in
dep
OR NSS Topdestroyed also the climax in
the stratigraphic se-
“ sphagnum ‘
Ne ae aaa oN peat rials (figs. 5-7).
ee De iit,
— EVIDENCE OF CLI-
i MATIC CHANGES
| ig TSE cig, a iT ae ae Lower ee carts
en eS, inert
“otile, a age ae, A at, Oe TD, pea * - :
ae eo Peat investiga
a oe tions are still an
5F . uh? S Fy Betula stumps _ unspecialized field in
RRS which the interrela-
‘a oe on oa A mpm HD AL EEE Me no Upper phrag- ge 3
[ore mar aoe res Be TO So one Se ANE PT BF Set te See om we mites and tion of climate, geol-
FS OS HR SONS He Se a site tes ogy, and vegetation
pugeganns & al] plays the paramount
oo PCE) Occasional role. Whether in the
+H betula stump service of science or
aeey SGRGGERG0RREER of agriculture and
Peer reir Lower phrag- = other _industries, the
Stittttttttttitit ~cladium peat +peat-land problem
sos sen ry eee es ore we = oe comprehends all the
Ce Re ee ee Rw ee ‘a
CL LLI LI LOE Hypnum peat complex correlations
[== SS === =} Macerated peat of plants and _ their
sean ee et ead habitat; hence it
® © © © © @| Hei ma should also furnish a
= ae we Ee historical perspective
: = =e veal ¥| Lake mud and the points of de-
= parture which lead to
It

Fic. 7.—Generalized section of peat deposit of
oe ee nk ‘. Tf ] J f+} R awe (29

past relations.
would be presumptu-

ous at this time to

attempt to draw a parallel between the climatic changes recorded
in the different peat deposits of this country. A reciprocal
relation can scarcely be discovered, even in a general way, from
only the few and incomplete records, and yet, although tentative,
a short statement descriptive of the preliminary results obtained

1921] DACHNOWSKI—PEAT DEPOSITS 75

Carex peat

Carex-
hypnum
peat

Hypnum-
carex
peat

Phragmites-
carex

peat

Feet in depth

ee ae
ae ee ee

ee ee ee

“coe ounce Micermied
cg Rancingeael yng troup neers a7 eed sam meer t
corti heat oben tn rising cngnpeenrs (in part
ee colloidal )

- eS SO Oo

= a Clay
Macerated
peat

Clay phase

Macerated
peat

Sandy
phase

Fine sand

- may beofinterest. A

full correlation can be
reached only by re-
peated efforts of this
kind. Emphasis will
necessarily fall upon
glacial formations, be-

fluctuations and a
cause in the age rela-
tion of peat deposits.
The general micro-
scopic analysis of the
plant remains is re-
served for a more
comprehensive paper
to follow.

With regard to the
order of age, from
older to younger, it
is advantageous to
compare briefly a few
peat deposits (figs. 8,
10, 12) located be-
tween Canton and
Cleveland, Ohio. In
this part of Ohio
several of the great
morainic systems of
the Wisconsin stage
of glaciation are
closely crowded to-
gether. They extend |
from Canton north-
ward as a massive
(interlobate) belt, and
show nearly all the
advantages of indi-
vidual distinction

76 BOTANICAL GAZETTE [AUGUST

without involving the. complications which occur in the broader
intermorainic tracts as a result of subsequent changes in drainage.
The general physical features of this area have already been
described (4). An extended account and delineation of the geology
and soils has been given by LEVERETT (17) and in the field opera-
tions of the United States Bureau of Soils (20, 21). A diagram-
matic representation of the successive positions of the ice border
and the location of the peat deposits is given in fig. 1.

The Canton peat deposit (fig. 8), like the Buckeye Lake deposit
(fig. 3) farther southwest, is among the first and the oldest in Ohio.
In both the basal layers of macerated plant remains represent
accumulations of peat which probably began while the ice border
was receding from its maximum position across Illinois, Indiana,
and Ohio to about the limits of the Bloomington group of moraines.
The growth of peat-forming vegetation in these two deposits
followed soon after the recession of the ice sheet, before the drift
had become drained by development of valleys on it.

Two seams of clay in the Canton deposit are noteworthy. Their
positions indicate that the early period of peat formation was at
least twice marked by climatic disturbances. The presence of the
two layers of clay between layers of macerated types of peat seems
to show that the ice readvanced to near this point into territory
that had been laid bare following the maximum extension of
the glaciers. In these states the western end of the Bloomington
group of moraines not only overrides the weaker ridges of the
Champaign moraines, but also extends into the ground occupied
by the Shelbyville morainic system which was formed at the
culmination of the Wisconsin stage of glaciation. The clay was
probably deposited along the border of the ice mass by the same
agencies that contributed the coarser material at the margin of
the moraine, while further out, in the water basins, sand and
finally clay were left. The deposition of clay may have taken
place chiefly during the retreat of the ice front, when climatic
conditions had become much warmer. It is not improbable that
these clay seams represent the loess material which is known to
cap the earlier morainic systems of the Wisconsin drift. Much of
the material from the loess covered plains may have been carried

1921] DACHNOWSKI—PEAT DEPOSITS rid

up by strong winds, forming at first a surface coating upon the
ice at the time the moraines were developing. The effect of
possible meteorological changes over wide areas, such as PENCK
and others have worked out, must be borne in mind. The shifting
of all climatic zones southward (26), caused by the general lowering
of the temperature during the Ice Age and the depression of sea-
level, points to the probability of this area as part of a relatively
windy arid belt. After the ice had melted back some distance, the
inorganic material may thus have come to be contributed to the
peat deposit.

The basal layer of macerated peat is somewhat silty, and has
a rather aged appearance. It is assumed, provisionally, to have
been formed during the first or Shelbyville period of deglaciation.
The layer of plant remains found overlying the basal peat has a
much fresher aspect, but the organic débris in both of the lower
layers of peat seems to fall short of reaching the greater variety
of plant fragments which occurs in the succeeding layers. Further
study of a microscopic nature, however, is necessary to establish
fully the character of the plant remains from each of these glacial
substages. The strongest evidence of an interval between the
formation of the basal macerated peat and of the overlying layer
of macerated plant remains is found perhaps in a comparison of
the character and amount of the uppermost seam of clay. This
clay seam is much more sharply terminated than the lower one,
and it is also worth noting that the upper thickness of the clay
stratum is compact and relatively free from plant remains. Whether
or not the evidence thus far at hand favors the view that the seam
of clay is derived from wind blown loess rather than from drift,
or differences in the strength of the outwash, of considerably
greater significance is the fact that the upper mineral layer consti-
tutes a distinct break in peat formation. The cause of this break
in the succession of peat materials must evidently have been a
change from colder climatic conditions, from a more or less notable
readvance, and a renewed aggression of the ice sheet.

Apparently the climate was undergoing amelioration at the
time, probably giving rise also to a lower water table. That such
oscillations have occurred is evident from the work of LEVERETT

78 BOTANICAL GAZETTE [AUGUST

and others. A certain degree of aridity seems to have prevailed,
not only during the withdrawal of the ice, but up to the period
which resulted in the formation of the Bloomington morainic sys--
tem. The Bloomington period of peat formation was stopped by
the upper seam of clay. This suggested correlation appears to
be correct, for the upper clay layer can be esniaeiete closely with
that part of the Valparaiso-Kalamazoo morainic
system which passes northeast of Canton through Portage County.
The principle members of this group of moraines show west of here
a marked differentiation of glacial lobes and a shifting of the lines
of axial ice movements. The glaciers, as shown by the studies
particularly of LEvERETT and others, encroached again over the
surface of land that had been vacated by the earlier recession of
the ice border. This readvance, the limits of which are marked by
a morainal belt reaching from eastern Illinois and extending north-
ward into Michigan to the vicinity of Kalamazoo and Battle Creek,
has usually been designated the late Wisconsin stage. It covers
a time of drift deposition reaching to the series of generally weak
moraines which are included in the Lake Border-Defiance system.

During the time which elapsed while this ice front receded, and
which may tentatively be called the Mississinawa glacial substage,
the third tier of macerated peat was formed and probably also
some of the superposed layers of fibrous plant remains. There is
hardly any feature in the structure of the Canton deposit so con-
spicuous as the fibrous layers of peat, which rest on and in places
grade into the underlying third basal bed of macerated organic
material. The Carex and Phragmites plant populations, from
which these layers of relatively coarse fibrous peat are derived,
appear to have grown at ground water levels much lower than.
those which prevailed at later glacial substages. The uppermost
beds of fibrous peat of more recent development contain an admix-
ture of aquatic plant débris. They do not represent in their texture
the features which would be characteristic of a gradual decrease
in available ground water coincident with the closing of water
basins by vegetation.

In the absence of more definite correlations, these three primary
series of peat layers, namely, the several basal layers of macerated
plant remains, the middle bed of coarsely fibrous peat, and the

1921] DACHNOWSKI—PEAT DEPOSITS 79

upper layers of partly fibrous plant components, might be inter-
preted as representing three great changes in water level. They

Bowsers 8 Ped fe
tN Cea

KS
PS pe

om Tana
ARRAN

\
!
Tr

IG. 9.—Location of peat deposit near Kent, Portage County, Ohio, and of
sounding illustrated in fig. 10; scale, 1 inch=1 mile (2.5 cm.=1.6 km.).

may correspond, therefore, to three climatic stages that left their
traces in the structure of the Canton deposit. From this it would
seem that a comparatively warm period with moderately humid

80 BOTANICAL GAZETTE [AUGUST

conditions must have been preceded and followed by two compara-
tively cool periods, characterized by changes between drought
and wetness greater in degree than seasonal variations. For this
interpretation, however, a series of various facts is doubtless
required. A consideration of the structural appearance of the
deposits in line north of Canton should give more adequate evidence
of such alterations. They represent in part a contemporaneous
and later age of peat formation which should bring into clearer
perspective the probable climatic conditions during and after the
close of the third glacial substage.

The recession of the ice front marked by the Valparaiso-
Kalamazoo-Mississinawa morainic system to near the border of
the Huron and Erie basins initiated the development of the Kent
(fig. 10) and the Mantua peat deposits (fig. 12) in the order named.
An examination of the profile sections suggests a long interval of
peat accumulation. In about the middle of the Kent deposit there
is evidence that here also an unusual disturbance had affected the
course of peat formation, and that a well marked climatic change
had occurred. The position of the layer of forest peat in the Kent
deposit suggests that the change is contemporaneous with the
deposition of the Lake Border-Defiance system.

At the bottom of the Kent deposit, overlying the bowlder clay,
are shells of fresh water mollusks, and above them a layer of plant
remains from aquatic vegetation. This is followed by macerated
material, a part of which is distinctly gelatinous. The upper por-
tion of the structureless débris merges into a layer of fibrous plant
remains, showing that a mat of sedges and other marsh plants had
covered the basin. When this stratum was formed, a mixed
deciduous but predominantly coniferous forest appears to have
been growing on the borders of the basin, which gradually
encroached and finally occupied the entire peat-land area. The
thickness of the layer of forest litter shows that the ground water
level at that time was below the surface soil, and that the tract
remained moderately moist for a considerable period of time.

It can scarcely be decided in the present state of investigation
whether or not the end of the Mississinawa glacial substage was
accompanied by a widespread dispersal of forest trees from south-

Ig2t]

eastern portions of the United States.

DACHNOWSKI—PEAT DEPOSITS

The first coarsely fibrous

layers of Carex-Phragmites peat in the Canton deposit, and espe-
cially the middle forest bed of the Kent deposit, certainly have a

suggestive feature
of resemblance.
Among land-laid
peat deposits, the
basal forest bed in
the Kankakee
Marsh near South
Bend, Indiana, ap-
pears to indicate a
corresponding time
relationship, the
climatic conditions
of which favored
-forest associations
more distinctly
southern in range.
Layers of coarse,
fibrous peat mate-
rial and of forest
peat seem to offer
the evidence of a
prolonged warm
Period, during
which migration of
deciduous shrub
and forest vegeta-
tion units might
readily have taken
Place to areas
considerably more

Feet in

depth

—

Se,
ALnN

Sphagnum peat
with tamarack
stumps

Carex peat

_ Macerated peat

Carex peat
Predo ntly

conifer forest
peat

Carex peat

Macerated peat
(in part col-

Marly phase
Marl

Clay

FI o.—Cross-section showing structure of peat
deposit i near Kent, Portage County, Ohio; elevation 1028
feet a.t.; location of sounding indicated on map (fig. 9).

northward than they are at the present time (14).

From these

facts there appears some support for the suggestion that the
probable range in temperature and precipitation as well as the
duration of this warm period made it possible for many trees

82 BOTANICAL GAZETTE [AUGUST

and shrubs to extend rapidly the limits of their distribution. It
is unwise, however, to venture more, since at the present time
definite stratigraphic and botanical data from peat deposits of
northern states have not been exhaustively studied, nor have the
investigations of the later quaternary deposits of the eastern and
southern coastal states been carried to a point where they could
be definitely correlated with the peat beds of this glacial substage.

There followed a wet period, during which the forest in the
Kent deposit seems to have become submerged. The weight of
the trees can scarcely have caused a sinking of the forest layer in
this basin, since its depth is small and the underlying layers of peat
material show no compression or disturbance. With the rise of
the water table a layer of fibrous material from sedges and various
other marsh plants began to accumulate above the forest stratum,
but there soon followed a more rapid increase in the water level.
The area became covered for a time with water.

The period of change recorded so conspicuously in the Kent.
deposit appears to be associated with the Lake Border glacial sub-
stage. It is readily correlated with the time which elapsed when
the front of the Erie lobe receded northward to the Port Huron
morainic system. As the ice in its retreat uncovered the Ohio
divide, inundation followed the escape of waters from the subse-
quent melting of the ice masses. No clay, however, entered into
the formation of the peat deposit. The Lake Border moraines are
practically free from loesslike silts, and apparently they were not
strong enough to spread a seam of clay over this basin. When
peat accumulation recommenced, there was again formed a layer
of macerated material, followed by a fibrous type of peat from
sedges, above which appears a stratum showing small twigs and
branches of shrubs. Once more the area had become cool and dry,
too severe perhaps for the free spreading of forests. Probably
many tree species were again driven southward and replaced by
more open vegetation, such as grassy marsh and shrubs. This cool
period meliorated in severity rather rapidly and became sufficiently
temperate for forests, for in the uppermost layer of peat are the
remains of tamarack (Larix sp.). The stumps of the trees are stand-
ing in the peat itself. The present surface vegetation is a dense stand

1921] DACHNOWSKI—PEAT DEPOSITS 83

~of tamarack. In the partially wooded portion grow heaths such
as Cassandra (Chamaedaphne) sp., Vaccinium corymbosum, and
others, while the ground cover consists largely of sphagnum mosses
with the cranberry and similar plants characteristic of sphagnum
bogs. The southern portion of this tract is under cultivation.

Turning to the Canton peat deposit, it is interesting to note
that the middle forest layer is wanting in this deep basin. The
type of peat material of the period contemporaneous with the Kent
middle forest layer consists of fibrous and relatively coarse plant
remains from sedges and to some extent from reeds. The quantity
of water must have diminished independently of the local alter-
ations in the water table, for layers of a fibrous texture accumulate
only under moderately moist conditions. The overlying peat
stratum, on the other hand, is formed from Hypnum mosses and
sedges, and has an admixture of macerated débris, clearly showing
the advent of a cool period.

The succeeding layers in the Canton deposit show a gradual
elimination of the Hypnum mosses as a peat forming component,
and they also indicate a return of atmospheric conditions swinging
toward a warmer climate. Before its cultivation the Canton area
is reported to have been a marsh with the margins partly forested.
Thus the uppermost layers of peat in the two deposits seem to
show that during their later history, from the last glacial substage
(the Port Huron time and the Lake Champlain period) to the
present, the amelioration of climate has been relatively more
steady than at any time since the culmination of the Wisconsin
period. The lack of structural diversity is related probably to the
distance of these deposits from the direct influence of the later
glacial substages.

he beginning of the Mantua peat deposit (fig. 12), it is reason-
able to infer, dates from the period of accumulation of Hypnum
mosses in the Canton peat deposit and the submergence of the
forest layer in the Kent deposit. In the Mantua deposit the
uppermost layers similarly point to the supplanting of a cool by
a more temperate period of climatic conditions, and to the migration
"of plants as an essential process in the sequence of peat materials.
It is worth noting that the forest layer has the stumps of tamarack

84 BOTANICAL GAZETTE [AUGUST

(Larix sp.) in the lower portion of the stratum; while those of
maple (Acer sp.), ash (Fraxinus sp.), and elm (Ulmus sp.) are
found in the forest litter nearer the surface. The degree of natural
drainage which established itself in time on the surface layers of
this deposit determined, probably in large part, the character of
the succeeding vegetation cover. Deciduous trees such as the red

U/ ares ape eee
SJ eB 9) Hef ere ay ? ee
Ug, : MSE st | >|

1203
Se *
GA
h (é) '
22 e .
) Vy
r) (6) 1
[0 O ‘
Vi MILNES, =
: Ci
\ e
Cy
Z£

Fic. 11.—Location of peat deposit near Mantua, Portage County, ee and of
sounding on lot no. g illustrated in fig. 12; scale, 1 inch=1 mile (2.5 cm. = )

maple, black ash, and elm are still the dominant trees in the present
surface vegetation of this tract of peat-land. Here again it is
obvious that much is not yet clear about the major changes of
climate until quite recent times, and that more extended and more
critical field studies are required upon northern deposits which
admit of ready comparison with the older peat accumulations. |
These questions of climatic changes from the later glacial sub-

1921] DACHNOWSKI—PEAT DEPOSITS 85

stages to the present are critically important, for they bear radically
on interpretations that have already been well supported in the
countries of northern Europe.

It does not lie within the sphere of this paper to review the
literature dealing with the probable causes which produced the
glacial period or its climatic changes. These and other considera-
tions are discussed fully by CLEMENTS (3), Douctass (9), HUNTING-
TON (11), and others.

The only question is - vA AA DA

how far the types |

of peat material and A Deciduous
their sequence in In IA ba gpd egg
peat deposits may rack stumps
furnish evidence of & A A

climatic effects = aes
during the succes- 3 carex peat
sively less extensive © a

positions of the ice = ast
border. The facts 6 SSS SSS SSS ee

given in this article ea | Marly phase
xen iG.

seem to indicate at ?@):| Marly sand
#1 9

least three if not Be

four major oscilla- Fic. 12.—Profile section showing sequence of strata

tions during which in peat deposit near Mantua, Portage County, Ohio;
elevation 1155 feet a.t.; sounding on lot no. 9, west

the climate fluctu-
ated between warm
and cold conditions, between periods of greater dryness and greater
humidity.

Summarizing the climatic changes since the disappearance of
the Wisconsin ice sheet in Ohio, the following may be stated ten-
tatively: In the record of a few Ohio peat deposits an irregular
Series of changes can be traced, due to effects of climatic influences.
Apparently twice a comparatively dry and cool period alternated
with a relatively warm and humid period. After glaciation
had reached its maximum extension, there followed two minor
periods of recession of the ice field, a time during which a cool and
dry climate bordered closely the glacial regions in this locality.

side of Center pad as indicated on map (fig. 11).

86 BOTANICAL GAZETTE [AUGUST

It was probably a period of winds, cooled from the ice sheet, and
of loess deposition. The accumulation of drifted, wind-blown
sand in the Kankakee, Indiana, area, portions of which were later
covered by peat materials from a basal forest, may be referable to
the first two glacial substages. In the general shifting of climatic
belts the cold climate along the border of the retreating ice prob-
ably passed into dry windy conditions. On the exposed ground-
till only marsh plants and low shrubs may have been the dominant
plant population. This period of relative aridity in turn gave
place to a second great advance of ice, the late Wisconsin, probably
not of as great severity as the first, after which a prolonged warm
and somewhat humid climate prevailed. This appears to have
been the period of invasion and wide dispersal of forest trees from
the south, and of a more northerly distribution of certain species
than is now recorded for them. As to the end of the late glacial
time, the climatic characteristics from the last glacial recessions
to post glacial and present conditions stand as yet considerably ill
defined. The evidences indicate periods during which the climatic
zones shifted again somewhat. There appears to have been a

return to cooler and drier climatic conditions, followed by a tem- -

perate and more humid period than exists at the present time in
the same localities. The present period is probably approaching
a climate of rising temperatures and (or) decreasing precipitation.
The botanical data, however, are as yet insufficient to permit more
definite conclusions, and they are wholly inadequate for drawing
a parallel between the past climatic conditions of different countries.

The writer has had considerable hesitation in publishing the
climatic correlations for the peat deposits of these great morainic
systems. Although the interpretation accounts for a series of
facts that are in need of being formulated, yet there might perhaps
be another way of correlating the field observations. For this,
however, the work of several years will doubtless be required.
This preliminary paper may aid in the meantime a field of peat
investigations to which Biytr (2), WEBER (35), and others have
been among the first contributors. With these major climatic
fluctuations as a basis, chronological data of considerable value
may perhaps be obtained by this method of peat investigations

1921] DACHNOWSKI—PEAT DEPOSITS 87

for several sciences, including archaeological research. In its
relation to the practical worker in peat-land problems it is hoped
this paper will suggest the influence which structural differences
in peat deposits necessarily exert upon a true estimate of the value
of peat deposits and upon the progress of peat-land utilization,
especially upon the plans, methods, and equipment which must
be adopted to convert suitable areas into productive sources of
national wealth.

Unitep STATES DEPARTMENT OF AGRICULTURE

LITERATURE CITED

Is BaREN, J. VAN, Zur Frage nach der Entwicklung des Chama Klimas
in den Niederlanden. Die Veriaderungen des Kli 1x. Internat.
Geol. Kong. Stockholm rto10. pp. 23-31. 1910.

2. BLytr, AxEL, Essay on the immigration of the Norwegian flora during
alternating rainy and dry periods. pp. 89. Christiania. 1876

3- CLEMENTs, F. E., Plant succession. An analysis of the development of
vegetation. Publ. Carnegie Inst. 242. 1916. :

ACHNOWSKI, ALFRED P., Peat deposits of Ohio. Ohio Geol. Survey.
Ser. 4, Bull. 16. ror2.

5. , Quality and value of important types of peat material. U.S.
Dept. Agric., Bur. Plant Industry, Bull. 802. roro.

6. ———, Correlation work in peat-land problems. Bor. Gaz. 70: 453-
458. 1920.

7: , Peat lag) Te in le United States and their classification. Soil

Science 10:453-465.
8. DocrurowskI, V. S., vit torfa. (Les espéces de tourbe) Viestnik torfi-
anovo diela 2:273-304. ‘
9. Douctass, A. E., Climatic cycles and tree-growth. Publ. Carnegie Inst.
289. 1910.
to. GEER, G. DE, A geochronology of the ge 12 ese dimes 11. Internat. Geol-
Kong. Stockholm, IQIO. pp. 241-253.
11. Huntincton, ELtswor tH, et al., The fiscatte factor as illustrated in arid
America. Publ. Carnegie Inst. 192. 1914
12. Keirnack, K., Begleitworte zur Karte der Endmoriinen und Urmstrom-
taler Norddeutschlands, Jahrb. K. Preuss. Geol. Landesanst. Berlin,
T9009, .30:507~510. IQII.
13. Kepperer, G. , Bestimmung des Vertorfungsgrades von Moor- und Torf-
proben. Mitt. Ver. Férd. Moorkultur Deutsch. Reich. Jahrg. 38:3-8.
1920.

Lal
a

w
o

31.

BOTANICAL GAZETTE [AUGUST

. Knowtton, F. H., The climate of North America in later glacial and

subsequent post-glacial time. Die Verinderungen des Klimas. 11. Internat.
Geol. Kong. Stockholm, 1910, pp. 367-370. r9I0.

. Konic, J., HASENBAUMER, J., and Grossman, H., Das Verhalten der

organischen Substanz des Bodens und der osmotische Druck derselben.
Landw. Vers. Stat. 69:1-91. 1908.

. LesquEREUX, LEo, On the vegetable origin of coal. Ann. Rept. Geol.

Survey, Penn. 1885. pp. 95-124. 1886.
LEVERETT, FRANK, Glacial formations and drainage features of the Erie
and Ohio basins. U.S. Geol. Survey, Monographs 41:pp. 802. 1902.

, Comparison of North American and European glacial deposits.
Zeitschr. Gletscherkunde 4:241-295, 321-342. I9I0.
LEVERETT, FRANK, and Taytor, FRANK B., The Pleistocene of Indiana
and Michigan and the history of the Great Lakes. U.S. Geol. Survey,
Monographs 53:pp. 529. 1915.

. Mooney, CHARLES N., TutrLe, H. Fotry, and Bownazzr, A., Soil survey

of Stark County, Ohio. U.S. Dept. Agric., Bur. Soils Field Oper. 1913.
PP. 39. IOr5.

Mooney, Cuartes N. et al., Soil survey of Portage County, Ohio. U.S.
Dept. Agric., Bur. Soils Field Oper. 1914. pp. 44. 10916.

. MEttIN, Exzas, and Opén, SvEN, Kolorimetrische Untersuchungen iiber

Humus und: Himifizierung. Sveriges Geolog. Undersékning, Ser. C, no.,
278. 1917.

. Post, Lennart von, Uber stratigraphische Zweigliederung schwedischer

Hochmoore. Sveriges Geolog. Undersédkning, Ser. C, no. 248. 1913.
, Om skogstridpollen i sydsvenska torfmosslagerféljder. Geolog.
Foreningen Stockholm Férhandl. 38:384-390. 1916.

. Potonté, H., Das Auftreten zweier Grenztorfhorizonte innerhalb eines

und desselben Hochmoorprofils. Jahrb. K. Geol. Landesanst. Berlin, 1908,
29: 398-409

. 1909.
Penck, A., The shifting of the climatic belts. Scot. Geogr. Mag. 30:
281-293. Igr4.

. Penck, A., and BRUCKNER, Epuarp, Die Alpen im Eiszeitalter. 3 vols.

Leipzig. 1909.

. RamMann, E., Beziehungen zwischen Klima und dem Aufbau der Moore.

Zeitschr. Deutsch. Geol. Gesells., 62:136-142. 1910.

. Rankry, W. Munn, The lowland moors (“mosses”) of Lonsdale (North

Lancashire) and their development from fens. Types of British Vege-
tation, pp. 256-259. Iorr.

. Russert, [sraArx C., Lakes of North America. Boston. 1895

SANDEGREN, R., Hornborgasjén, En Monografisk framstallning av dess
postglaciala utvecklingshistoria. Sveriges Geolog. Undersdkning, Ser. Ca,
no. 14. 1916.

1921] DACHNOWSKI—PEAT DEPOSITS 89

23,

33-

Ww
on

SAURAMO, MarTrI, Sac AT gprs Studien iiber die ital =
in Siid Finnland. Fennia, Bull. Soc. Géogr. Finlande 41:1-44.
SERNANDER, RUIGER, a the evidences of postglacial changes of ane
furnished by the Cop obmcre! of cidoagin oo Geolog. Féreningen
Stockholm, Férhandl. 1908, 30:465-47

3-
4. ———, Die schwedischen i elisth ie vii postglazialer Klima-

schwankungen. Die Verinderungen des Klimas. 11. Internat. Geol. Kong.
Stockholm 1910. pp. 197-2
U

246. 1910
. WEBER, C. A., Uber die Nesetatina. und Entstehung des Hochmoors von

Kisehanal. 1902.

- ———, Was lehrt der Aufbau der Moore Norddeutschlands iiber den

Wechsel des Klimas in postglazialer Zeit? Zeitschr. Deut. Geol. Gesells.
62:143-162. 1910

. ZAILER, VIKTOR, Die Entstehungsgeschichte der Moore im Flussgebiete

der Enns. Zeitschr. Moorkultur und Torfverwertung 8:105-154, 171-
203. IQIO.

LIFE HISTORY OF CORALLINA OFFICINALIS
VAR. MEDITERRANEA*

S. YAMANOUCHI

The group of red seaweeds known as the Cryptonemiales
includes many species displaying a wide variety of form. The
structure of the reproductive organs and the mode of reproduction
found in this group cannot be ascertained adequately by the study
of a single species. In order to distinguish the Cryptonemiales
from the other groups of Florideae, the method of reproduction, as
existing in Dudresnaya, has constantly been cited as characteristic
and representative of the entire group; but it is merely charac-
teristic of that genus. Moreover, our present knowledge of
Dudresnaya is confined to its morphological features. In any
systematic arrangement of the forms belonging to the ill-defined
Cryptonemiales, Corallina should always be placed near the summit.
This does not mean, however, that the structure of the reproductive
organs and the mode of reproduction are more complicated than
in other forms belonging to this group. About 30 years ago,
Sotms-LAUBACH published his original work on the structure of
Corallina, but no cytological work was attempted, and the life
history of the plant was not established. Consequently, a cyto-
logical study of Corallina was made from material secured at the
Bay of Naples, Italy.

Origin of conceptacle

Generally the conceptacles are formed at the ends of branches
of the thallus. The reproductive organs, which arise within the
conceptacles, originate from these so-called disk cells which com-
pose the central portion of the growing apex of each branch. The
disk cells located at the periphery continue to divide and grow up
around the reproductive organs, leaving only a small aperture or
ostiole at the apex, thus forming the conceptacle. The three kinds

* Translated by CLARENCE C. BAUSMAN, assisted by C. Cursa, from Bot. Mag.
Tokyo 27:279-285. figs. 1-8. 1913.

Botanical Gazette, vol. 72] [90

1921] VAMANOUCHI—CORATIINA gl

of reproductive organs (antheridia, carpogonia, and tetraspores)
are produced in conceptacles on three different individuals.

Nuclear division in vegetative cells

Nuclear division is very common among any of the vegetative
cells, but is most conspicuous among the actively growing (disk)
cells at the ends of the branches. The cell structure varies more
or less according to the position of the cell, but as a rule the nucleus
occupies the central portion of the cell. One or sometimes two
large vacuoles are present, and also many chromatophores. The
cytoplasm seems to be distinctly alveolar in structure. The
nucleus in the resting condition contains one and sometimes three
or four irregular nucleoli. The chromatin material, during the
resting condition of the nucleus, consists of small granules scattered
throughout the karyolymph. Upon approaching the period of
nuclear division, the nucleus slightly enlarges, and the chromatin,
which up to this time was in the form of granules, increases in
amount and finally becomes organized into a definite number of
chromosomes. The male and female individuals possess twenty-
four chromosomes, while the tetrasporic individuals have forty-
eight. The contents of the nucleolus gradually become decreased
with the formation of the chromosomes, and when the chromo-
somes have arranged themselves in an equatorial plate, the nucleolus
has completely disappeared.

In the prophase a small, granular, centrosome-like body makes
its appearance at each of the two poles of the nucleus in the cyto-
plasm near the nuclear membrane. Within the nucleus spindle
fibers are soon formed, originating from the centrosome-like body.
The alveoli of the cytoplasm immediately surrounding this
- centrosome-like body form branched astral rays. In later prophase
the centrosome-like body becomes enlarged, and thus the centro-
sphere is produced.

In the metaphase the chrémosomes divide, and when the two
groups of daughter chromosomes reach the opposite poles, the
daughter nuclei are soon formed. Up to and including the forma-
tion of the daughter nuclei, the centrosome-like body retains its
characteristic form. With further growth of the daughter nuclei,

92 BOTANICAL GAZETTE [AUGUST

however, it gradually decreases in size, and at the approach of the
resting stage of the nuclei it becomes unrecognizable. With the
return of the period of nuclear division, the centrosome-like bodies
reappear, as just described, at the opposite poles of the nucleus.
SWINGLE and others who studied Sphacelaria and Stypocaulon
maintain that the centrosome or “central body” persists from one
mitosis to another. Harper appears to be of the same opinion,
as a result of his work on Lachnea and Phyllactinia. As regards
_ Corallina, the two centrosome-like bodies appear for the first time
at the period of nuclear division, and gradually disappear with the
formation of the daughter nuclei. Thus these structures are not
permanent organs of the cell, but arise de novo at each mitosis to
carry on the mechanism of nuclear division.

Formation of tetraspores

By normal cell division the disk cell divides into two portions,
the upper portion becoming the tetraspore mother cell, while the
lower portion becomes the stalk cell. The tetraspore mother cell
in its growth assumes a clavate form, while its nucleus increases in
size. At first the structure of the nucleus appears to be the same
as that of the vegetative nucleus, but by the time the conceptacle
has developed sufficiently to be recognized as such, the nucleus of
the tetraspore mother cell enters upon the stage of synapsis. In
Corallina the chromatin material is so scanty that a continuous
spireme cannot be formed, but remains in two groups of small
granules at the poles of the nucleus. When the synaptic period
has passed, a centrosome-like body appears at each pole. In the
metaphase a group of twenty-four bivalent chromosomes becomes
arranged in an equatorial plate, and the paired chromosomes split
longitudinally and separate into two groups. The first nuclear
division, which is the heterotypic division, is soon followed by the
second, or homotypic division. With the completion of the second
division, there are formed four nuclei within the tetraspore mother
cell, each of which possesses twenty-four univalent chromosomes.
Later the tetraspore mother cell, by means of three cleavage fur-
rows, becomes divided into four portions, each of which develops
into a tetraspore containing one nucleus. The tetraspores then

1921] : VAMANOUCHI—CORALLINA 93

escape from the conceptacle, float about freely in the water, and
after becoming attached to a suitable substratum proceed to
germinate.

Germination of tetraspores

The first nuclear division at the time of germination of the
tetraspores shows twenty-four chromosomes. The same is true
for. the second and third divisions. With:culture material the
size of the plants obtained from germinating tetraspores was
limited to thirteen cells. Throughout all these divisions there
was no change as regards the number of chromosomes. The infer-
ence, therefore, is that such tetraspores, in nature, would give rise
to sexual plants of normal size, possessing twenty-four chromosomes.

Formation of antheridium

The disk cell divides into two portions. The upper portion,
which ultimately becomes the antheridium, is much smaller than
the lower one; and is situated to one side of the latter. The two
cells gradually become considerably elongated, the upper cell con-
tinuing to elongate until it finally attains a remarkable length. At
the same time its nucleus divides, one daughter nucleus migrating
to the extreme distal portion of the cell, while the other daughter
nucleus remains in the lower portion. Just below the upper daugh-
ter nucleus a cell wall is formed, dividing the original upper cell into
a very short terminal cell and a very long lower cell. The terminal
cell becomes much enlarged and assumes a spherical form; the
nucleus also enlarges greatly and occupies the larger portion of
the cell. Thus the antheridium of Corallina is composed of a
larger, spherical, terminal cell and a very much elongated, narrow,
stalk cell. Later this spherical cell separates from the filiform
stalk cell and functions as the spermatium. More than one antheri-
dium may be formed from the same disk cell. The antheridial
nuclei have constantly twenty-four chromosomes. The sperma-
tium has a thin cell wall derived entirely from the mother cell, and
when compared with other Florideae it is homologous with a
unicellular antheridium. In 1911 SvEDELIUS, after having studied
Delesseria, reported that the spermatium simply consists of the

94 BOTANICAL GAZETTE [AUGUST

naked protoplast discharged from the mother cell. I believe, how-
ever, that this would be disproved by a careful reinvestigation.

Formation of procarp

Each disk cell produces one carpogonial branch or procarp.
The steps in the development of the procarp are as follows: The
disk cell divides to form two cells, the upper one becoming the
auxiliary cell and the lower one the stalk cell. The auxiliary cell
then gives rise to a cell at one side of its exposed terminal portion,
and then similarly to another cell at the other side. Thus two
sister cells are produced from the auxiliary cell, situated side by
side. Of these two cells, the first one formed has become greatly
elongated by the time the second sister cell is formed. The nucleus
of the older sister cell divides to form two nuclei; one nucleus
remains in the enlarged basal region of the cell (carpogonium) and
becomes the carpogonial nucleus, while the other one enters the
hairlike upper portion of the cell (trichogyne) and functions as the
trichogyne nucleus. The trichogyne is separated from the carpo-
gonium by a constriction. The younger sister cell, which is usually
provided with one nucleus, ceases to grow further at an early stage
in its development, and simply remains as a non-functional structure
beside the carpogonium formed by its older sister cell. Every one
of the many disk cells, at the growing tips of the thallus branches,
produces a procarp.

As just described, each procarp is composed of a stalk cell, auxil-
iary cell, carpogonium, and trichogyne, together with the small non-
functional sister cell of the carpogonium. The structure of the
procarp of Corallina, therefore, would seem to be simpler than that
of other Florideae; yet in many Florideae the procarps are solitary,
or, as in the case of Ceramium, two occur side by side. In Coral-
lina, however, 60-70 or sometimes over 100 independent procarps
occur in a group within the same conceptacle, and after fertilization,
before the formation of the carpospores, they fuse with one another,
resulting in the formation of one common structure.

Fertilization and formation of cystocarp
The trichogynes project above the surface of the conceptacle

and are thus freely exposed to the sea water. A floating sperma-
tium comes in contact with the apex of the trichogyne, adheres to

1921] YAMANOUCHI—CORALLINA 95

it, and discharges its contents into it. The trichogyne nucleus now
begins to disintegrate. The spermatium nucleus proceeds down-
ward, finally reaching the carpogonial nucleus, with which it fuses.
At this time the auxiliary cell unites with the auxiliary cells of
adjacent procarps, resulting in the formation of a large central cell
within the conceptacle. The passage between this central cell and
the carpogonium broadens. The sporophytic or fertilized carpo-
gonial nucleus now passes into the large central cell. Since the
sporophytic nuclei of all the procarps within the conceptacle
migrate into this central cell, there are therefore over 100 sporo-
phytic and also about the same number of gametophytic or auxil-
iary cell nuclei included in this common cytoplasm. The two
kinds of nuclei found in the central cell differ as regards their
structure. The sporophytic,nuclei are usually large, rich in chro-
matin, and possess forty-eight chromosomes; the gametophytic
nuclei are small, possess twenty-four chromosomes, and most of
them gradually disintegrate.

Each sporophytic nucleus moves to the periphery of the central
cell, where it divides to form two nuclei. One nucleus enters the
cell which has been formed on the outer surface of the central cell,
while the other nucleus remains inside the central cell. From the
cell produced on the external surface of the central cell, a chain of
cells is formed in basipetal sequence. These cells enlarge, become
spherical, and when they have attained the size of tetraspores,
gradually become constricted, separate, and finally escape from the
conceptacle as carpospores.

Germination of carpospores

After the carpospores have escaped from the conceptacle, they
begin to germinate within twenty-four hours. The first nuclear
division is of the normal type and shows forty-eight chromosomes.
The same is true of the second and third divisions. ‘The sporelings
continue to develop until the 17-celled stage is reached, all of the
cell divisions being of the normal type and showing constantly
forty-eight chromosomes.

1. The male and female plants of Corallina possess twenty-four
chromosomes, while the tetrasporic plants have forty-eight chromo-
somes.

96 BOTANICAL GAZETTE [AUGUST

2. During the formation of tetraspores the forty-eight chromo-
somes become reduced to twenty-four. The tetraspores on ger-
mination show twenty-four chromosomes, and since twenty-four
chromosomes appear in the vegetative mitoses of the sexual plants,
the inference is that the latter arise from tetraspores.

3. The nuclei of the reproductive cells (spermatia and carpo-
gonia) of the sexual plants possess twenty-four chromosomes. The
sporophytic or fusion nucleus, as a result of fertilization, has forty-
eight chromosomes. ‘The sporophytic nuclei give rise by division
to the carpospores, which also possess forty-eight chromosomes.
The carpospores on germination show forty-eight chromosomes,
and since forty-eight chromosomes appear in the vegetative mitoses
of the tetrasporic plants, it is inferred that the tetrasporic plants
originate from carpospores.

4. The male and female waite 4 are gametophytic, while the
tetrasporic plants are sporophytic. The sporophytic generation
begins with the formation of the sporophytic or fusion nuclei,
extends through the formation of the cystocarp and carpospores,
and finally terminates with the formation of tetraspores on the
tetrasporic plant. With the formation of the sige tacit the
gametophytic generation commences.

5. Thus Corallina is another clear example of the alternation
of a sexual plant (gametophyte) with a tetrasporic plant (sporo-
phyte), the cystocarp occurring as an early phase of the sporophytic
generation.

Toxyo HicHer NorMAL ScHOOL
Toxyo, JAPAN

INTRA-OVARIAL FRUITS IN-CARICA PAPAYA
H. F. BERGMAN
(WITH SIX FIGURES)

An unusually interesting teratological phenomenon came to
notice recently when in cutting open a fruit of papaya (Carica
Papaya L.) five small. secondary fruits were found within the seed
cavity. Externally the fruit containing them was in no way

1.—Papaya fruit cut longitudinally, showing seeds and secondary fruits in

Fic.
Position; one secondary fruit turned over to show production of seeds; 3.

different from any other specimen to indicate the presence of the
secondary fruits. These were attached near the basal end of the
fruit, growing out from the placenta and replacing the seeds. In
addition to the four conspicuous fruits there was found also one
very much smaller. Fig. 1 shows four of the inclosed fruits in situ.
Only the style and stigma of the fourth, the smallest fruit, is
Visible.

97) : [Botanical Gazette, vol. 72

98 BOTANICAL GAZETTE [AUGUST

Four of the five fruits consisted of an ovary surmounted by a
sessile stigma. The ovary was not completely developed, in any
case only a single carpel probably being represented. Each of the
four larger inclosed fruits produced seeds. This
may be seen from the figure, one of the fruits
being placed to one side and turned: over to
show the incomplete development and the pro-

Fic. 2—Sketch of duction of ovules. The stigmas, instead of
small secondary fruit 2 Sa i ‘
only partly: visible in being flattened and laciniate, as in normal fruits,
fig.1; naturalsize. | were capitate, considerably swollen, spongy,

and -with tuberculate surface. The smallest
fruit has a very small ovary, without ovules, the capitate stigma
being borne on an elongated style (fig. 2). The inclosed fruits
were yellow, being somewhat paler than normal fruits.

Fic. 3 Fic. 4

Fics. 3, 4.—Fig. 3, portion of epidermis of secondary fruit showing stomata;
160; fig. 4, portion of epidermis of normal fruit showing stomata; 160.

A microscopic examination of the epidermis of these fruits
(fig. 3) showed it to be made up of cells similar in shape but some-
what larger than those of the epidermis of normal fruits (fig. 4).
This similarity extended even to the presence of stomata. The
guard cells were without chloroplasts. The only evident external
difference in the epidermis of the inclosed fruits from that of
normal fruits was in the absence of the coating of wax which the
latter possesses in a marked degree. In cross-section the structure
of the inclosed fruits resembles closely that of normal fruits, the

1921] BERGMAN—INTRA-OVARIAL FRUITS 99

epidermis being thinner in the former. This and the absence of
wax is probably due to the fact that they were not exposed. In all
respects the seeds resemble those produced by a normal fruit.
The embryo was found to be present in the several seeds examined,
and to all appearances, so far as could be ascertained with a hand
lens, was of normal form and size.

Some two or three months after finding these specimens,
another set of intra-ovarial fruits of papaya was supplied to the
writer through the kindness of Dr. L. O. KuNKEL, of the Hawaiian

Fic. 5.—Secondary fruits from seed cavity of papaya; slightly reduced

Sugar Planters’ Experiment Station. These are shown in fig. 5.
Only two of them are comparable in form and size to those shown
in fig. 1. These two were rough surfaced, as may be seen from
the illustration. The lower one of the three middle specimens
Shown in fig. 5 differed in being turbinate and smooth surfaced.
In cross-section it was circular, without a seed cavity, but having a
single vascular bundle near the center. All five fruits in this case
wereaverylightcream color. Nomatured seeds were found, although
the two larger ones had a placental surface with a few rudimentary
ovules. The styles of the larger ones were filiform, tipped by a
very small capitate stigma. An examination of the epidermis of

100 BOTANICAL GAZETTE [AUGUST

three of the five specimens showed it to be similar to that figured for
the other specimens (fig. 3).

These intra-ovarial fruits, although they occur on the placentae,
cannot with certainty be regarded as metamorphosed ovules.
Instead it is more probable that they were produced from buds
which developed adventitiously in places which would normally
be occupied by ovules. The occurrence of adventitious formations
within the ovary replacing ovules has been observed by several
‘botanists. Masters" figures and describes a silique of Cheiranthus

Fic. 6.—Portion of papaya fruit showing secondary pistil as proliferation of stem
axis; Xr. 25:

Cheiri which contained an adventitious silique, replacing an ovule,
within an ordinary silique, and also a grape which had another
grape inside in the place of a seed. He also quotes and shows
figures of a case described by BERKELEY? of a carnation in which
the placentae bore both ovules and carpels. In this case transi-
tional forms between the normal ovules and their carpellary trans-
formations were found. Some of the carpels derived from ovules
produced secondary ovules. MAsrTERs states that in the carnation

* Masters, M. T., Vegetable teratology. London. 1869

2 BERKELEY, M. J., Gardener’s Chronicle, September 28, 1850 (p. 612).

1921] BERGMAN—INTRA-OVARIAL FRUITS IOI

specimens described by BERKELEY “the nucleus of the ovule was
not developed.” No transitional forms between ovules and
secondary fruits such as were described by BERKELEY in the
carnation were found in these papaya specimens.

The formation of secondary fruits within the ovary is evidently
not uncommon in the papaya; and has been observed by many
persons. It is said that in some instances the intra-ovarial fruits
are exact models in miniature of the normal fruits. No informa-
tion was obtained as to whether or not such fruits have a seed
cavity with ovules or seeds.

An instance of the formation, in a different manner, of a second-
ary pistil within the seed cavity. has also been observed. In this
case the secondary fruit, instead of arising from the placenta in
place of an ovule, occurred as a proliferation of the vascular axis
which extends from the pedicel through the pericarp (fig. 6). The
form of the pistil is not representative of the normal form in pistil-
late flowers, but is of the type that is to be found in a petunia or
other similar flower. On cutting the ovary transversely it was
found that no seed cavity was present. A single vascular strand
was located in the center.

Masters refers to intra-carpellary prolification and states that
“it occurs most frequently in plants having a free central placenta,
though it is not confined to them, as it is recorded among Bora-
gineae.”” No instance is cited, however, of a proliferation of the
form here described.

UNIVERSITY oF Hawa
Honotu

LEAVES OF CERTAIN AMARYLLIDS!
AGNES ARBER
(WITH EIGHT FIGURES)

In a previous memoir’ attention has been drawn to the existence
of leaves with a phyllodic type of anatomy among the Amaryllida-
ceae. In the present paper it is proposed to discuss certain special
cases drawn from this family.

Leaf-anatomy of Narcissus

The foliage leaves of Narcissus consist typically of a linear limb
(fig. 1, 2) and a short sheathing base (6). In the very young leaves
the sheath is relatively the more conspicuous organ, while the limb
is scarcely developed. This relation is shown in fig. 2, drawn from a
leaf which slightly exceeded 1mm. in length. In N. Tazetta L.
limbless sheathing leaves occur, in addition to foliage leaves in
which both sheath and limb are developed. An examination has
been made of the anatomy of the limb in the following species,
representing the various sections of the genus:

- SUBGENUS EUNARCISSUS
Section AJAx.—N. Pseudo-narcissus L.
Section GANYMEDES.—JN. triandrus L.
Section QuELTIA—JN. incomparabilis Mill., N. Jonquilla L., N. junci-
folius Req., N. reflexus Lois.
Section Genutn1.—J. biflorus Curt., N. poeticus L.
Section HERMIONE.—N. Tazetta L.

SUBGENUS CORBULARIA
N. Bulbocodium L., N. monophyllus T. Moore.

Anatomy of the type interpreted as phyllodic? has been found
in Narcissus Pseudo-narcissus, N. triandrus, N. incomparabilis,

* This paper represents part of the work carried _ oe the tenure of a Keddey
Fletcher-Warr Studentship of the University of Lon

2 ArBER, AGNES, The phyllode theory of the momentos leaf, with special
reference to anatomical evidence. Ann. Botany 32:465-sor.

Botanical Gazette, vol. 72] [102

1921] ARBER—AMARYLLIDS 103

N. Jonquilla, N. biflorus, N. poeticus, and N. Tazetia; that is, in at
least one species from each of the five sections of the subgenus
Eunarcissus. The leaf of N. Tazetta may be taken as a type (fig. 3).
In this species there is a single series of main bundles lying roughly
midway between the upper and lower epidermis (7b), and a series
of smaller bundles lying near the lower epidermis (nb’). These

Fics. 1-6.—Fig. 1, Narcissus sp. (garden var.): leaf showing relation of sheath -
to limb : staies Xo.5; fig. 2, Narcissus sp. (garden var.): young leaf, slightly
more than 1 mm. long showing predominance of sheath; fig. 3, N. Tazetta L.: trans-
verse section of limb of leaf, X14; fig. 4, NV. Bulbocodium L.: transverse section of
limb of leaf, x23; fig. 5, N. monophyllus, T. Moore.: transverse section of limb of
leaf, X23; fig. 6, Zephyranthes candida Herb.: transverse section of limb of leaf, X14;
1, limb; 6, sheath; nb and nb’, series of normally orientated bundles; ib, series o
inverted bundles (xylem in black, phloem in white, and outlines of lacunae in dotted
ine),

Zephyranthes

Strands are all normally placed with the xylem upward. In addition
there is a series of inverted bundles (ib) toward the upper surface.
N. triandrus has a slender grooved leaf with peripheral bundles,
whose xylem faces inward. The leaf anatomy of N. Tazetta and

104 BOTANICAL GAZETTE [AUGUST

N. triandrus may be compared with that of other Amaryllids in
which inverted bundles occur toward the upper surface, as Zephyr-
anthes candida Herb. (Amaryllis nivea Schult.) (fig. 6). In these
cases the structure is interpreted as indicating that the limb is of a
petiolar nature.

The only plants belonging to the subgenus Eunarcissus in which
non-phyllodic anatomy has been found are WN. juncifolius Req. and
N. reflexus Lois.; in these all the bundles are normally orientated.
This type of structure, however, although apparently rare in

————————— SS

7 PLETE SI .
L/L GCE

<7
|

AAS

—

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S
SSN
\
NN
ANN
Aas

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AN
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\\
ANY
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o \

Fics. 7, 8.—Eurycles sylvestris Salisb.: fig. 7, leaf, petiole incompletely shown,
Xo.25; fig. 8, small part of righthand side of leaf near apex, Xo.5.

Eunarcissus, is characteristic for the subgenus Corbularia. In both
N. Bulbocodium (fig. 4) and N. monophyllus (fig. 5) only two series
of bundles are found, both of which are normally orientated; the
inverted series toward the ventral surface is absent.

The interest of the leaf anatomy of Narcissus, from the stand-
point of the phyllode theory, lies in the fact that within the same
genus there are examples of phyllodic anatomy (fig. 3), and of a
reduced form of anatomy (figs. 4, 5) in which the loss of the inverted
bundles results in a structure to some extent simulating that of a

1921] ARBER—AMARYLLIIDS I05

true lamina. That the anatomical type shown in figs. 4 and 5 is
indeed a reduction from that shown in fig. 3, and that the series
should not be read in the reverse direction, are suggested by the
general morphology of the subgenus Corbularia. The extreme
corona development and the tendency to zygomorphy in the hoop-
petticoat daffodil, as CHurcu™ has suggested, point to its being
a more advanced and specialized type than the various forms of
Eunarcissus.

Pseudo-lamina of Eurycles

The leaf of Eurycles sylvestris Salisb. furnishes a very char-
acteristic example of what has elsewhere? been described as the
““pseudo-lamina’’ of the monocotyledon. The blade (fig. 7) is
large. A herbarium specimen was measured in which it was 19 cm.
long by 25.5 cm. wide. Fig. 7 shows that the primary skeletal
system of this pseudo-lamina may well be interpreted as originating
by the separation of the veins of the distal end of the petiole. The
secondary and tertiary venation is also of interest from this point
of view (fig. 8). A very large number of the secondary veins are
unbranched and unconnected, and it is noticeable that the tertiary
veins are extremely irregular; some pass from one secondary vein
to another, some go from one secondary vein to a primary; while
others leave a secondary vein, form a loop, and return to the vein
whence they arose. The anomalous character of this venation
seems not inconsistent with the view that the blade of the mono-
cotyledon is an organ which is still at the experimental stage of its
evolution from an expanded petiole.

Batrour LaporaTory

CAMBRIDGE, ENGLAND

3 Cuurcu, A. H., Types of floral mechanism. Part I. Oxford. 1908.

A HOMOSPOROUS AMERICAN LEPIDOSTROBUS brs
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 283
JOouN, M; (COULTER AND: W: jf. G. Lanp

Strobili of Lepidodendron so perfectly preserved that they can
be sectioned and their minutest structures studied are common in
European coalfields. Many of these strobili show heterospory,
the megasporangia being at the base of the strobilus, the micro-
sporangia above. The extensive literature of the subject is fully
cited by Scott’ and SEWARD,’ and need not be repeated here.
The extensive American coalfields, with but two exceptions, have
yielded nothing but casts as yet. Perhaps the reason for this
seeming scarcity of petrified material is that it has not been looked
for carefully by competent observers.

In 1911 there came to this laboratory from Professor JOHN L.
TittoNn, of Simpson College, Indianola, Iowa, a well preserved
fragment of a strobilus from the coalfields of Warren County,
Iowa. This fragment, from above the middle of the strobilus,
showed small spores, but of course nothing concerning heterospory
could be determined. This specimen, the first American Lepi-
dostrobus to be sectioned, was fully described by CouLTER and
LanD.’ TILTON reexamined very carefully the place where the
first fragment was found, and discovered several fragments of
cones in a very good state of preservation, and evidently the same
species as the first fragment. These he kindly sent to this labora-
tory. A few fairly well preserved stems of Lepidodendron also
have been received from the coalfields of western Indiana. No
cones were found, but it is evident that these fields will repay
intelligent search.

Among the later fragments obtained from Titron were four
pieces which matched perfectly, showing clearly that they were

t Scott, D. H., Studies in fossil botany. London. 1909.

2 Sewarp, A. C., Fossil plants. Cambridge. rgro.

3 CouLTeR, J. M., and Lanp, W. J. G., An American Lepidostrobus. Bot. GAz.
51:440-453- figs. 23. I9II.

Botanical Gazette, vol. 72] {106

1921] COULTER & LAND—LEPIDOSTROBUS 107

from the same strobilus, the tip being the only part missing. The
restored strobilus was 22 cm. long and 5 cm. in diameter at the
base. The structures were well preserved, with the exception of
the axis, which is replaced by calcite and pyrites. The strobilus
is mature; the sporangia have all opened and are empty excepting
here and there a few spores. Enough sections were made to show.
its character, from the base to the broken tip, the general condi-
tion of the strobilus being almost exactly identical with that
of the fragment described by CouLrer and Lanp. There is no
appreciable difference in size of any of the spores, both those in the
basal sporangia and in the sporangia near the apex averaging 27 in
diameter. It seems probable, therefore, that this particular species
of Lepidostrobus is homosporous, although it is possible that the
spores found in the basal sporangia entered through the dehiscence
slits. It would seem almost impossible that, in such a well
preserved and compact strobilus, all of the megaspores, if there
were any, could have escaped. The real solution of the problem
lies in the finding of younger strobili which have not yet shed any
spores. Negative evidence, however probable, is never conclusive;
but the evidence in the present case is so strong that it seems safe
to infer that this species of Lepidostrobus is homosporous.

The form genus Lepidostrobus was originally established to
include all of the strobili of Lepidodendron. Later it was found
that all such strobili could not be included, even in a form genus,
so that “true” Lepidostrobus is restricted to those strobili of
Lepidodendron characterized by “the great radial elongation of
the sporangium, and its attachment by a long and narrow inser-
tion to the upper surface of the sporophyll-pedicel throughout its
length.”* The chief interest in connection with these strobili is
the question of heterospory. If heterospory has been attained by
all these forms, the origin of the homosporous Lycopodiales is
left in the region of the unknown. Certain species of Lepidostro-
bus are known to be heterosporous, and all of them are suspected.
In one well preserved specimen the microsporangia occur in the
upper part of the strobilus and the megasporangia in the lower part,
as in certain species of Selaginella. The inference has been that

4Scort, D. H., Studies in fossil botany. London. 1909.

108 BOTANICAL GAZETTE [AUGUST

all the species of Lepidostrobus have probably reached the level of
Selaginella in this feature, or, in other words, that Selaginella is
the modern representative of this group. In the Lepidostrobus
form referred to, the microspores are 20u in diameter, and the
megaspores 800, so that there is no question as to the great
differentiation in size. The discovery of a Lepidostrobus, therefore,
which is evidently homosporous is worthy of record and considera-
tion. If these old strobili included both homosporous and hetero-
sporous forms, the history of the modern Lycopodiales would
become simpler. It would also emphasize the independent origin
of heterospory in lines which could by no possibility be related.

UNIVERSITY OF CHICAGO

CURRENT LITERATURE

BOOK REVIEWS
A textbook of botany

FritcH and SALIsBURY! have prepared a sequel to their Introduction to
the study of plants. In the more elementary volume the microscopic details
were omitted, and therefore the present volume supplies these details for
those who wish to know more about plants. Although the anatomical structure
and reproduction of plants are the main subjects, the authors have included
enough physiology and ecology to relate structure to function, and to indicate
the responses of structures. In connection with reproduction, also, there is a
supplementary chapter on heredity and evolution. It is interesting to note
that the authors have abandoned the old method of types, and have treated
groups as a whole, which certainly results in a better conception of the organiza-
tion of the plant kingdom. They have also developed the economic contact
when appropriate, stating that the purpose is “to combat the frequent igno-
tance of botanical students with respect to the economic aspects of their sub-
ject.” This tendency is developing strongly in all the sciences, and is to
be commended as developing a more general appreciation of science, and also
as helping to do away with the old artificial distinction between “pure” and
“applied” science.

The first part of the volume, devoted to anatomy, is an excellent genera
Presentation of the subject, and one that isneeded. There has been a tenden
in the more recent texts to deal chiefly with the anatomy of the reproductive
structures, with perhaps some supplementary information in reference to

vascular anatomy, omitting the numerous other structures that enter into
the structute of plants. In the second part, the life histories of the great groups
are considered in oe sequence, relating the facts to conditions of
living and to future progres

The volume is well Shasta and should prove to be a valuable addition
to the botanical texts for English students.—J. M. C

Principes de botanique

It is a gratification to botanists, long familiar with the work of CHopart,
to greet the third edition of his well known textbook.2 The first edition
* Fritcu, F. E., and Sarispury, E. J., An introduction to the structure and
prouction ‘of plants. 8vo. pp. viii+-458. figs. 230. London: G. Bell & Sons. 1920
T, R., Principes de botanique. Troisiéme édition, revue et wicmuease.
ee 4878. te get. Genéve: Edition Atar. 1921.

109

bi ge) BOTANICAL GAZETTE [AUGUST

appeared in 1907, and the third was ready in 1914, but its publication was
prevented by the war and the unfavorable conditions of printing. The author
has included the more important recent results of investigation, presented in
his very attractive style, and with abundant illustrations.

The organization of the subject is peculiar to CHopatT, and therefore the
volume has a flavor of its own. The four general divisions of the subject are as
follows: ‘“‘ Physiologie générale,”’ “La cellule, les tissus,”’ ‘‘ Physiologie spéciale,”
and ‘‘Génétique.” The chapter topics under this general organization are
often unusual. For example, practically everything usually treated under
morphology, with the exception of anatomy, is presented under “special
physiology,” the evident suggestion being that structures are only significant
in connection with their functions.

It is unusual for a book of nearly 900 pages to contain only ten chapters,
and the subjects are suggestive of the organization. They are as follows:
under general physiology, “Constitution de la matiére vivante” and “Capta-
tion et Papetosmation de l’énergie”’; under the cell and tissues, “La cellule,”
“Organogénie,” and ‘Anatomie’; under special physiology, ‘‘Fonctions de
circulation et d’élaboration,” ‘‘Fonctions de relation,” and ‘‘Reproduction”’;
under genetics, ‘‘ Variations, hérédité,”’ and ‘“‘Conclusion” (theories of the
origin of species). The volume closes with a brief classification of plants.—
J. MAC.

MINOR NOTICES

Dictionary of botanical equivalents.—ARTSCHWAGER and SMILEY3 have
prepared a very convenient dictionary which gives accurate translations of
technical terms which are not usually found in ordinary dictionaries. All
technical terms have been omitted when the English equivalent would be
practically a repetition of French and German terms of Latin or Greek origin.
As the compilers state, it is ‘a practical hand-book, accurate within the
limits set for it.””. The publishers have also provided interleaved blank pages,
so that users of the volume may amplify the list. It will certainly prove 4
very convenient volume for the reader of French and German botanical
literature, both in saving time and in insuring accuracy.—J. M. C.

NOTES FOR STUDENTS

Chlorophyll inheritance.—Considerable interest has always been focussed
upon reported cases of non-Mendelian inheritance. For the most part these
have later been explained satisfactorily on a Mendelian basis, so that at the
present time the only clearly recognized cases of non-Mendelian inheritance

3 ARTSCHWAGER, Ernst, and Smitey, Epwina W., Dictionary of botanical
equivalents (French-English, German-English). 16mo. pp. ii+137. Baltimore:
Williams & Wilkins Co. 1920.

1921] CURRENT LITERATURE III

are certain types of chlorophyll inheritance. WuNGE‘ makes a hopeful attempt
to classify all known cases of chlorophyll inheritance according to the following
scheme:

I. The characters are situated in the nucleus and show Mendelian segre-
gation, self-colored ee usually being dominant. To this class belong the

kn alniba, citrina, chlorina, variegata, and albomarginata forms of
Melandrium, pye eral Pelargonium, Mirabilis, Urtica, Aquilegia, Lunaria
(CorRENS, Baur, and others). The most complex case on record is one
recently solved by LrnpstRoms in which the F, of a trihybrid gives the remark-
able ratio of 36 green:9 virescent-white:7 yellow:12 white.

II. The characters are situated elsewhere than in the nucleus and do not
show Mendelian inheritance. This class is further split up in the following
interesting way: (a) The characters are transmitted by the plastids them-
selves. In this case plants which are endowed with both green and colorless
plastids may, through the uneven distribution of plastids of the two types at
cell division, give rise to pure green and pure white areas, really a ‘‘somatic
segregation.” Such areas, through seed, will breed true to their local char-
acter. There is one known case, the “mosaic” Pelargonium zonale of Baur, in
which plastids evidently accompany the male nucleus at fertilization, for
here inheritance is bi-parental. In all other known cases no plastids accom-
pany the male nucleus, and inheritance is strictly maternal. In -this last
group we find the albomaculata forms of Mirabilis (CoRRENS), Antirrhinum
(Baur), and Primula (GREGORY).

b) Thecharacters are situated in the cytoplaian. In this case no thorough-
going ‘“‘somatic segregation” is possible. A ‘“‘hybrid” plant, combining the
character for normal chlorophyll development with the alternative character
for chlorophyll deficiency, will have these characters well diffused and inter-
min;

en distribution of these effective elements in the scan, resulting in
; of “di

the elements. Pure albinos or pure green individuals are never produced by
these “hybrids.” Here too we find in one case, the albomaculata form of
Capsella (IkENO), the male nucleus seems to be accompanied by some cyto-
plasm, since the chlorophyll inheritance is bi-parental. In the only other
case on record, the albomaculata of Humulus (WINGE), the male evidently
contributes no cytoplasm, for inheritance is strictly maternal.

This classification seems fairly satisfactory, but it involves some funda-
mentally different conceptions from those of CoRRENS and Baur. Probably

*Wince, O., On the non-Mendelian inheritance in variegated plants. Compt.
Rend. Lab. Carlsberg 34:1~20. figs. 4. 1919.

5 Linpstrom, E. W., Concerning the inheritance of green and yellow pigments
in maize seedlings. Genpiics 6:QI-I10. 1921.

5 wh BOTANICAL GAZETTE [AUGUST

the most significant fact, and one about which there can no longer be any
me is that chlorophyll inheritance is sometimes Mendelian and sometimes

on-Mendelian. Naturally this suggests that other types of characters also
may be, at least in some cases, non-Mendelian in inheritance.—M.
COULTER

Plagiotropic shore plants.—From the results of experiments carried on
largely with Atriplex prostratum, TURESSON® reached the conclusion that the
external factor causing prostrate growth is intense illumination, but that the
growth movements are really geotropic in their nature. Emphasis is placed
upon the fact that there are apparently two distinct sorts of plagiotropy, the
one resulting from congenital habits of growth, and the other from response "
to environmental conditions. At times a single species, such as the one
under experiment, will prove to consist of two such forms.—GEo. D. FULLER.

Haustoria of Meliola.—Miss Dompce,’ in continuation of her studies of
South African Perisporiaceae, has examined the haustoria of Meliola, whose
species occur chiefly on leaves and shoots of forest trees and shrubs. She
determined that the species are true parasites, sending haustoria into the cells
of the host, penetrating the cuticle and in some cases sclerenchyma cells.
The species differ in the length and character of the penetrating filament.—
LMC.

North American flora.—Part 2 of volume 32 includes a continuation of
Rubiaceae by STANDLEY. The preceding part included 20 genera, to which the
present part adds 41 more. uch the largest genera are Bouvardia with 30
species (12 new) and Exostema with 26 species (5 new). The remaining 5
new species are distributed among the smaller genera.—J. M. C

Vegetation of Paraguay.—Continuing his report on the scientific results
of a botanical expedition to Paraguay, CHopat® discusses the Apocynoceae,
Urticales, and Araceae observed and collected. A number of new species are
described, and rather extensive notes are made on distribution and ecology.—

EO. D. FULLER

6 TURESSON, aig The cause of plagiotropy in maritime shore plants. Lunds
Univ. Arsskrift. N.F. Avd. 2. 16:no. 2. pp. 32. pls. 2. 1910.

7 Dowce, Era -, South African Perisporiaceae. VI. The haustoria of the
genera Meliola and rai Trans. Roy. Soc. S. Africa 9:117-127. figs. 7. 1921.

§ CuopaT, R., La végétation du Paraguay. Fasc. 3. Geneva. pp. 291-379. figs-
53. 1920.

VOLUME LXXII : NUMBER 3

LEE
DOTANICAL (GAZETTE

SEPTEMBER 1921

EFFECT OF DIRECT CURRENT ON CELLS OF ROOT TIP
OF CANADA FIELD PEA
Henry F. A. MEIER
(WITH PLATES II, III, AND THREE FIGURES)
Introduction
EFFECT OF CURRENT ON LIVING STRUCTURES

The numerous researches to determine the effect of the electric
current on plants may be divided into two general classes: first,
those in which certain organs or entire plants were subjected to
electricity, the effect being measured by increase or absence of
growth; second, those in which the effect of the current on the
individual protoplast formed the basis of study. Among those
interested in problems of the second class, Amicr (1) as early as
1818 suggested, although without experimental evidence, that
protoplasmic streaming was of electrical origin. Impressed by
AMici’s suggestion, and by the striking results of his own and
DutrocHet’s work on the relation of temperature to protoplasmic
streaming, BECQUEREL (2) attempted to show that the direct elec-
tric current had the same effect on protoplasmic streaming as varia-
tions in temperature. He placed cells of Chara in a helix, some
parallel and others at right angles to the direction of the electric
current, using a battery of 10-30 elements, without in any way
influencing the rate of flow. With stronger currents, making
direct connection with the cells by means of platinum electrodes,

113

II4 BOTANICAL GAZETTE [SEPTEMBER

protoplasmic streaming was inhibited. After a time the flow was
resumed. No disorganization of the cells occurred.

JURGENSEN (12) worked with Vallisneria,. noting the effect of
the direct current on protoplasmic rotation. He placed sections of
leaves on a special object holder, in distilled water, with copper
electrodes in contact with the ends of the section. The effect was
observed with a microscope giving a magnification of 235-680
diameters. Using 2-4 Grove cells, the speed of rotation of proto-
plasm was decreased, and long continued exposure to such weak
currents brought about an inhibition of the streaming. If the
current was discontinued after slowing down the rotation, but
before it had entirely stopped, the original speed of rotation was
reacquired after a time. When rotation had completely stopped,
even though the current was broken immediately, movement was
never resumed. Stronger currents produced the same effect as the
weaker currents in much less time, the current from 30 cells sufficing
to produce immediate and permanent inhibition of rotation. If the
current was continued, the protoplasm contracted and gradually
_ migrated toward the end of the cell nearest the anode, where it
formed a dense mass against the wall. At break of current this
mass would rebound toward the opposite end of the cell. On
reversing the direction of current the mass migrated toward the
opposite end of the cell, that is, toward the now positive end.
JURGENSEN regarded these phenomena as coordinate with results
he had previously obtained with unorganized bodies.

Du Bots-REymonp (7) had previously published similar results,
experimenting with starch grains in the cells of a section of living
potato tuber. Movement toward the anode was observed, and, as
in Vallisneria cells, a reversal of current brought the starch grains
to the opposite wall.

KUHNE (14), using the direct current on a plasmodium of a
myxomycete, grown on the slide between platinum electrodes 4
mm. apart, reported nuclei moving toward the anode, the cytoplasm
toward the cathode. In the cells of Tradescantia stamen hairs the
entire cell contents moved toward the anode. The ends of the cells
toward the cathode changed from their characteristic purple to
- green, and the opposite end changed to a light red color. KtHNE

1921] MEIER—ROOT TIP . IIs

experimented further with the effect of the current on unicellular
organisms. Using platinum electrodes, he passed a direct current
through a drop of water containing Actinosphaerium. The first
visible effect of a weak current was the contraction of the pseudo-
podia lying in the direction of the electrodes. If the current was
continued or increased, the pseudopodia lying in the path of the
current became vacuolated, the vacuoles on the periphery burst,
and the protoplasm of the rounded central portion of the organism
began to disintegrate on the side toward the anode. This con-
tinued until the whole organism was disintegrated. KiHNE states
that the phenomena described for Actinosphaerium hold in general
for such forms.

VERWORN (21) repeated and verified KijHNe’s observations,
using non-polarizable electrodes and extending the work consider-
ably, especially with reference to free-swimming protozoa. He
found in Paramoecium and other free-swimming forms a shrinking
at the end toward the anode and a swelling at the opposite end,
which phenomenon he regards as illustrating a general tendency to
increased contraction on the side toward the anode. He found that
some protozoa migrate toward the anode, others toward the cathode.

CARLGREN (3) observed that in Volvox the long axis of the colony
is placed parallel to the lines of the current, and that there is a
movement toward the cathode. If the current is long continued,
the colonies move away from the cathode and sometimes gather at
the anode. The movement of the flagella on the side toward the
anode was inhibited, that on the opposite side not affected. Simi-
larly to VERWORN’s observation on Paramoecium, CARLGREN
noticed in Volvox an anodal shrinking and cathodal swelling with
migration of the colony-forming cells (gonidia) within fixed colo-
nies toward the.anode. It is interesting to note his further
statement that strong currents produced shrinking and swelling on
the sides toward the anode and cathode respectively in dead speci-
mens. Furthermore, he produced this shrinking and swelling in
dead Paramoecia and Amoebae. CARLGREN concludes that the
physical effect of the current (electrophoresis) accounts for many
of the supposed stimulation effects on free swimming forms, and
that it plays a large part in electrotaxis.

116 BOTANICAL GAZETTE [SEPTEMBER

Date (6) experimented with the effect of the current on five
different species of infusoria found parasitic in the intestine of the
frog. The organisms were exposed to the current in various solu-
tions: neutral isotonic saline, slightly acid, and slightly alkaline
solutions (using litmus as indicator). The organisms were exposed
to the current in a trough with unglazed earthenware sides about
I cm. apart, mounted on a slide, the ends of the trough being made
of sealing wax. Non-polarizable brush electrodes carried the cur-
rent to the porous earthenware sides. The results were very inter-
esting. In slightly alkaline solution the organisms migrated toward
the anode; when in slightly acid solution, toward the cathode. It
is true that not all of the five species examined were equally sensitive
to the acid and alkali treatment; that is, it required longer treat-
ment in the solutions for some species than for others in order to
produce the same effect. In more concentrated salt solutions
(good electrical conductors) the migration of the organisms was
inhibited.

More recently LILLIE (15) exposed to the direct current various
animal structures: isolated nuclei, nuclei of spermatozoa, small
leucocytes, and nuclei from lymphoid tissue, also muscle cells teased
out in sugar solution, red blood corpuscles, and larger forms of
leucocytes. These were suspended in N/4 cane-sugar solution
(iso-osmotic with physiological salt solution). In freshly drawn
frog’s blood, the majority of the red corpuscles moved slowly (at an
average speed of 120-130 w per minute) toward the anode, many
showed no migration whatever, and a few moved toward the cath-
ode. The minute lymphocytes moved more rapidly toward the
anode at a speed of 1500 w per minute. The medium sized leuco-
cytes were usually slightly negative (moved toward the anode) or
indifferent. The larger leucocytes, however, with more cytoplasm,
were in almost all cases decidedly positive (moved toward the
cathode). The nuclei obtained by teasing thymus gland and the
heads of spermatozoa moved rapidly toward the anode. The rate
of the latter was about 2.0mm. per minute. LILLie£’s conclusion,
that ‘‘the direction and speed of living cells and portions of tissues
are chiefly dependent on the electrical characteristics of their con-
stituent colloids,” seems justified.

1921] MEIER—ROOT TIP I17

In 1914 Harpy (9) published a short note on the migration under
influence of the direct current of the contents of cells of the onion
root tip. His methods and results were briefly as follows. The
roots were placed horizontally between non-polarizable electrodes,
the final lead to the tissue being some of the fluid in which the roots
had been growing. As to the density of current used and the time
of exposure, the author states: ‘‘A field of 5-20 volts per cm. was
established for from 1 to 10 minutes, when the root was instantly
fixed in acetic-absolute. Strength of field to which the living
matter was actually exposed cannot be calculated.”’ The effect
produced was uniform, and varied only with intensity of current
-and time of exposure. The nucleus was usually slightly drawn out
from a sphere to an ellipsoid, with the long axis parallel to the
direction of the current flow. The nucleus maintained its position
in the middle of the cell. The cytoplasm collected usually at the
end of the cell toward the cathode, although frequently condensed
into an equatorial plate. Within the nucleus the bulk of the solids
collected at the side toward the anode. The nucleolus usually
migrated toward the anode. No influence was exerted on division
figures, spindles and chromosomes showing no sign of orientation
or displacement whatever.

A careful review of the literature of this type of work reveals
that current intensity was seldom measured accurately, and in
most cases even when measured the results are not always repro-
ducible because the organisms or organs studied were usually
mounted in water, which acts as a partial conductor of current
(conductivity varying with quantity of liquid used, electrolytes
present, temperature, etc.), and in such experiments it is impossible
to determine what part of the current flowed arlene the plant
and what part through the water.

EFFECT OF CURRENT ON PARTICLES SUSPENDED IN LIQUIDS

The fact has long been known that finely divided particles
suspended in water or other poorly conducting media will migrate,
if the electric current is passed through the liquid, toward one or
the other of the electrodes. Suspensions in water of starch, par-
ticles of paper, earth, asbestos, finely divided gold and copper all

118 BOTANICAL GAZETTE [SEPTEMBER

move toward the positive pole. The particles of methyl violet,
magdala red, lead, and bismuth move toward the negative pole.

REvss (20) of Moscow seems to have been the first to discover
the phenomenon of electrical migration variously known as electro-
phoresis or cataphoresis. He found that when two poles of a
battery are immersed in a liquid and separated by a membrane the
liquid will move through the membrane toward one of the two
electrodes, and consequently the levels on the two sides of the
membrane will not be the same. He discovered furthermore that
while water moved toward the cathode, particles of various sub-
stances suspended in the water moved toward the anode.

That not all liquids migrate toward the cathode was first
announced by QUINCKE (19). Oil of turpentine and absolute ethyl
alcohol ‘‘that contained an organic impurity”’ migrated toward the
anode. That the nature of the containers plays a part in deter-
mining the direction of flow was shown by the fact that in a glass
tube lined with sulphur, oil of turpentine changed about in its
direction of flow and migrated toward the negative pole. Water,
however, was uninfluenced by the sulphur-lined tube and migrated,
as in glass, toward the negative pole. The inhibiting influence of
electrolytes on the movement of particles in suspension in an
electric field was discovered by JiiRGENSEN (11). Suspensions of
carmine in solutions of sulphuric acid, copper sulphate, and sodium
chloride gave no evidence of movement when subjected to the
current. On dilution of the easily conducting solutions, the par-
ticles again responded to the current.

That water, when absorbed by a semisolid material, will migrate
was shown by Du Bots-REyMonp (7). Incidental to this work was
the invention of the non-polarizable electrode, which consists essen-
tially of a short glass tube plugged at one end by moist kaolin, or
by a camel’s hair brush. Above the kaolin the tube is filled with a
solution of ZnSO, into which dips an amalgamated zinc rod which
is connected with the source of current. The semisolid used by
Du Bois-REYMOND was a cylinder of egg albumin. The non-
polarizable electrodes were brought in contact with the ends of
the cylinder, and in passing the current the end in contact with the
positive electrode developed a constriction a short distance from

1921] MEIER—ROOT TIP 119g

the surface of contact with the clay. The constriction became
hard to the touch, the remainder of the cylinder swelling somewhat.
When the current was reversed, the constricted end became soft
and enlarged and the opposite end became constricted.

In repeating a part of JURGENSEN’s work, QUINCKE discovered
that not under all conditions do the particles in suspension move
toward the positive pole. Starch grains in water in a glass tube,
as well as particles of silk, cotton, and paper migrated toward the
positive pole when suspended in water, and toward the negative
pole when suspended in oil of turpentine. The theory in explana-
tion of these phenomena of poorly conducting liquids migrating in
one direction and suspended particles in the opposite direction under
the influence of the electric current, was propounded by HELMHOLTZ
(10). The fundamental assumption of this theory is that at the
surface of contact of any suspended particle there exists a double
electric layer. If the particle bears a negative charge, ‘the layer of
medium immediately surrounding it bears a positive charge. On
passing the current a displacement of one system against the other
takes place, the liquid particles migrating toward one pole, the
suspended particles toward the opposite pole. How the charge
originates is not explained.

An explanation of the movement in opposite directions of oil of
turpentine and water, and substances suspended in them, was first
suggested by CorHN (5). He showed that with reference to the
sign of the charge of a solid in contact with a liquid, the substance
with the greater dielectric constant is positive to the other sub-
stance. The dielectric constant of oil of turpentine is 2.23, that of
glass 4~7 (according to composition), and that of water is 81. In
agreement with this explanation, glass is positive in oil of turpen-
tine and negative in water. Water has a much higher dielectric
constant than most other substances, and, as we have seen, most
substances are negatively charged in water.

Observations on electrophoresis in colloidal ‘‘solutions” or sols
were published by Picton and LInDER (18) in 1892. Such colloidal
sols consist essentially of very finely divided ultra-microscopic
Particles suspended in a liquid. Since LrnpER and Picron’s publi-
cation the work has been much extended, and the conclusions seem

120 BOTANICAL GAZETTE [SEPTEMBER

inevitable that each colloidal particle bears a surface charge, which
in some cases is negative and others positive, as indicated by the
characteristic differences in the migration of different colloids.
Furthermore, the researches of LINDER and Picton show that the
sign of charge possessed by the particles in a hydrosol bears a
definite relation to the chemical composition of the particles, acid
particles bearing a positive charge and basic particles a negative
charge.

PERRIN (17) extended the work and formulated the following
rule: “In the absence of polyvalent radicals, all non-metallic sub-
stances become positive in liquids that are acidic and negative in
liquids which are basic.”

Harpy (8) found that colloidal particles of derived albumins
“move with the negative” (that is, they bear a negative charge
and move toward the positive electrode) “if the reaction of the
fluid is alkaline, with the positive stream if the reaction is acid.”

The present work was undertaken with the idea of determining
in a more or less quantitative way the effect of the direct electric
current on the protoplast, the actual amount of current flowing
through the organ being under control at all times. The investi-

gation consists of two phases: first, that of cytological effect pro-
duced; and second, the combining of two factors, time and current
intensity, to produce death of the protoplasts.

Materials and methods

Young seedlings of Pisum sativum of the variety known as
White Canada Field Pea were chosen as the best material for this
work, although onion, lupine, and Scarlet Runner bean were tested
and the same cellular phenomena produced. The pea seedlings
were grown in moist sawdust in ordinary 8-inch flower pots. The
seeds were soaked in water for 12-24 hours, when all those not of
uniform size were discarded. The hulls were removed and the
seeds planted in the moist sawdust with the radicles pointing down-
ward. The pots were then placed in the greenhouse. This method,
if the moisture conditions of the sawdust are correct, will produce
uniform germination and seedlings with straight radicles. Two
lots were planted each day, one in the morning and one in the

1921] MEIER—ROOT TIP : 121

evening, giving a choice of between 200-400 seedlings perday. The
pots of seedlings were carried to the laboratory where the experi-
mental work was done. In subjecting the seedlings to the current
the following method was employed. The seedlings were subjected
to the current one at a time in a moist chamber (text fig. 1) made
of plaster of Paris and consisting &E

of a box 18 cm. high, 10 cm. wide, /

and 7 cm. deep with one side open.
A slab of plaster of Paris, cast \
to fit closely, was set against the

open side to serve as a door.

Through the top of this chamber |

the two non-polarizable electrodes il
were inserted. These were made e |
as described earlier, but in actual
practice it was also found that
inserting the copper conducting =
wires without the zinc and zinc
sulphate gave no_ polarization |

2 b&b

within 30 minutes, and with fre-
quent changes of the moist kaolin
was regarded as entirely safe.
Before setting up the elec-
trodes, the moist chamber was
placed in water for 20-30 minutes.
This insured against the roots _ Fis. 1-—Moist eee
being exposed to a drying atmos- to to moist kaolin Guoagh glass tubes;
phere while being exposed to the 4, D, kaolin in contact with extremes
current. The arrangement of the of i he ye ea i ie —
conducting wires, together with 04 attached to glass tube of upper
resistances and measuring instru- electrode by rubber bands.
ments, are diagrammed in text
fig.2. Band B', represented as binding posts in the diagram, con-
sisted in reality of an ordinary lighting socket with key. From
this socket a cord connected to an ordinary wall socket served as a
source of current from the 110-120 volt direct current circuit. In
some cases for added resistance a series plug with 4, 8, or 16 candle

122 BOTANICAL GAZETTE [SEPTEMBER

power lamps was introduced at the wall socket. The current source
in all cases, however, was thesame. The sliding contact rheostat R
has a resistance of 1770 ohms and a capacity of 0.45 amperes; while
Rt has a resistance of 464 ohms and a capacity of 1.2 amperes. The
voltmeter V was attached to the binding posts C, C'. The milli-
volt meter A (text fig. 2) was of Weston Electrical Instrument
Company manufacture, with an upper range of 150 milliamperes
and a lower range of 1.5 milliamperes. M represents the moist
chamber.

The seedlings were sacetally lifted from the sawdust, the adher-
ing particles brushed off with a small camel’s hair brush, the length
measured with a small millimeter rule, and then by means of
tweezers they were placed on the small glass fork which served as a

Fic, 2.—Apparatus and measuring instruments

support and which was attached to the upper electrode by means
ofarubber band. The cotyledons of the seedling were now brought
in good contact with the moist kaolin of the upper electrode, and
the lower electrode (shaped like the letter J) moved upward so that
the kaolin came in contact with not more than the first millimeter
of root tip. The door was now placed in position and the current
turned on with the key of the socket at B, B'. The time of exposure —
was measured with a stop watch. During exposure voltage and
amperage were read on the instruments.

For the cytological phase of the investigation the moots, imme-
diately after exposure, were killed in Flemming’s fluid. It should
be stated that control seedlings were suspended in the moist cham-
ber, in every case, near those being exposed to the current, and the
roots killed and sectioned as the treated roots for comparison.

1921] MEIER—ROOT TIP 123

For that phase of the investigation relating to current intensity
and time of exposure required to produce death, the seedlings were
placed immediately after treatment in moist pine sawdust in glass
battery jars. A stick the size of a lead pencil was pushed down
next to the glass, the seedling placed in the opening thus made, and
the sawdust carefully brought around the root. Figures on labels
placed above each seedling served for identification when obser-
vation was again made, usually 24 hours after treatment. From
4-6 controls were placed in each jar of 12-15 treated seedlings.

All seedlings were carefully selected with special reference to
length and diameter, those not corresponding to type being rejected.
Only roots of 15-20 mm. length were used and of diameter as nearly
uniform as examination without actual measurement could select.
No practical means suggesting itself of measuring the diameter of
the roots before exposure to current, the approximate diameter of
the roots used was found as follows. Free-hand sections were made
of 125 roots (carefully selected as if for treatment with the current),
3-4 mm. from the tip, the sections placed in a drop of water on a
slide and diameter measured under the microscope with eyepiece
micrometer. It was found that all fell within the following meas-
urements: long diameter, 1.03-1.18 mm; short diameter, 0.84-0.96 —
mm. It will be seen from these dimensions that the roots were
somewhat flattened. The cross-sectional area of the roots varied
then from approximately 0.7 sq. mm. too.9 sq.mm. The diameter
is an important factor, since on it depends the density of any given
current intensity per unit area. It should be understood that
these ranges are the extremes, the majority exhibiting no such
variation as the extremes might indicate.

With the method described the actual current flowing through
the tissue can be measured and read from the milliammeter, and
calculated for the unit area. More or less just criticism is often
made of the method of exposure to current of unicellular organisms
in electrotactic experiments when the material to be examined is
placed in liquid. The amount of current flowing through the
organism depends therefore on whether or not the liquid surround-
ing it is'a good conductor. If the liquid medium is a poor con-
ductor, the current will pass in large measure through the organism;

124 BOTANICAL GAZETTE [SEPTEMBER

if the opposite be true, very little if any of the current will pass
through the organism. It is very evident that, since the conducting
power of the medium is vastly increased by small amounts of
electrolytes, the conductivity of the liquid is an ever-changing
value. It is likewise evident that the same objection applies to
roots in water through which the current is passing. Furthermore,
the literature of electro-physiology is filled with references to cur-
rent strength as weak, medium, strong, or with the mere statement
of the number of cells used, with no statement of resistance in the
circuit, so that actual current intensity cannot be determined, and
difficulty is experienced in even approximating the conditions of
the experiment. With the materials and methods just described
these difficulties are avoided.

Observations
KILLING EFFECT OF CURRENT

If a seedling with a root of 15-20 mm. in length and of 0.7-0.9
sq. mm. in cross-section is exposed in the manner described to a
current of o.3 milliampere, the following changes take place. In
about thirty seconds the root begins to lose its normal color and
' becomes watery in appearance. If the current is continued for
two minutes or longer, numerous very fine droplets of liquid appear
over the surface 3-6 mm. from the tip. If the current is now
stopped and the root tip tested, it will be found to be quite flaccid.
Furthermore, measurement shows that the root is now from 0.5-1.0
mm. shorter than before the current was passed. An exposure of
a longer period than two or three minutes results in the root becom-
ing more or less translucent, and on testing after such longer
exposure it is found to have become even more flaccid. In the
preliminary experiments roots were treated with varying amperage
and for different time periods, then fixed, sectioned, and stained.
While the cytological pictures were similar except as to degree of
intensity of results, they were not comparable with each other; for
example, it was difficult to produce the same result with a 0.4 milli-
ampere current and a o.5 milliampere current by varying the time.

After much experimentation, in an effort to arrive at somewhat
comparable cytological results, had ended in failure, it was found

1921] MEIER—ROOT TIP 125

possible to establish in a fairly definite way the quantity of current
and the time required to produce death of the root. This was
accomplished by numerous trials using a constant amperage, and
varying the time factor until exactly the time exposure required
(using that particular amperage) to produce death was determined.
This method yielded comparable cytological results. Current and
.time factors were varied from 0.6 milliampere for fifty-two seconds
to 0.05 milliampere for thirty to thirty-five minutes. Longer expo-
sures were also made for as long as two hours at o.o1 milliampere.
In the determination of whether or not a certain exposure to
current produced death, roots immediately after treatment were
planted in moist sawdust as previously described. Examination
_was made after a lapse of twenty-four hours and record of condition
made. Roots so treated, current intensity of 0.3 milliampere for
two and a half minutes or longer, will after twenty-four hours appear
a chalky white at extreme tip and exhibit considerable shriveling
in the region of rapid elongation. If such a root is tested by being
drawn lightly between thumb and forefinger, it offers little resist-
ance, and flattens readily. It is quite evident that the entire root
tip of 1.5 cm. is dead. If subjected for a less period than two and
a half minutes to this current intensity, a majority of the roots will
show the shriveling in the region of rapid elongation and above, but
the first 4-5 mm. of the root will be more or less translucent, quite
different in appearance from the chalky white previously described,
and quite firm to the touch. It is evident in these cases that such
roots are dead above the first 4-5 mm. of the tip, and that the cells
are still in a living condition in the extreme tip. This conclusion
is further strengthened by the fact that in a great many cases these
roots will show curvatures at the tip. These curvatures take no
specific direction with reference to how the current is applied. The
seedlings were always set into the apparatus with the cotyledons
toward the front, yet the curvatures appeared in every plane, and
varied from a slight crook to a right angle curve, or in some cases
even a bending back on the main axis toa U-shape. These curva-
tures suggest unilateral injury which stained preparations in no
case reveal, and indicate a problem of great interest upon which
it is planned to do further work.

126 BOTANICAL GAZETTE [SEPTEMBER

The criteria by which a root was judged to be dead, living, or
partly dead are the following. When a root after twenty-four
hours was distinctly shriveled and drying in the upper region, that

TABLE I
CURRENT 0.6 MILLIAMPERE, 120 VOLTS; CRITICAL TIME 52 SECONDS
_ Sone Time of Average ead
ESS Numbes Direction sapouare pepe ( ty oe betas above ae
used current seconde a curvature only also
5 aN ee ee ee 5 15 +0.5 4 5 °
Wee ee een 5 30 +O.2 am 5 fo)
Soa eset 5 40 —0.4 4 4 I
Ee gl ere 5 45 —0.5 3 5 °
Cie ein seas 5 50 54 3 3 2
Oe ess pees ee 6 50 art Sek 2 zz 4
TEES Io Pe. —I.I ° fe) Io
TS PTS ces: to 52 —1.2 I I 9
og ct) Cee eters Io 55 —1I.3 ° ° To
POPES oe II s 55 —I.1 I I To
POR Wor ae Mew 5 s 60 —0.9 ° ° 5
1 ens Ee 5 s 60 —o.16 ° ° 5
TABLE II
CURRENT 0.5 MILLIAMPERE, IIO0 VOLTS; CRITICAL TIME 65 SECONDS
Pee Time of | Averag' Dead
Lot number pies a“. set gad gloss a, eae Eine wg fogs

used current ieee a ot curvature only alss
Ne sie es 5 20 +1.0 3 5 °
PEN og rte 5 4 40 +0.1 3 4 I
Yee re ee 5 ‘ 45 << Og 4 4 I
Seve cans 5 \ 50 0.90 4 4 I
Oe eee chess 5 55 —I1.1 2 2 3
baer al oa 5 s 55 —O.1 a! 4 T
Vek i ae 10 { 60 —0.3 I 2 8
Z, Os iliiceig. .. I5 60 —0.6 5 4 Il
48, 27, 10.0 50%6.5 16 y 60 —0O.7 3 6 to
MEO. aa 12 \ 65 —0.7 I ¥ it
T4F IB ee 10 h 65 —1I.I ° ° 10
a CR a i I 7O —o.8 ° ° 5
ro Papa agipaeeesin ee 5 70 —1.0 ° ° 5

portion was regarded as dead. In nota single case in all tests made
did this part revive after having reached this stage. A chalky
white appearance of the first 4 or 5 mm. of tip, together with the

1921] MEIER—ROOT TIP 127

exhibition of loss of turgidity, by showing little resistance to flat-
tening by gentle pressure (being drawn between thumb and fore-
finger) was regarded as evidence that this portion of the root was

TABLE III
CURRENT 0.4 MILLIAMPERE, 100 VOLTS; CRITICAL TIME 90 SECONDS
..: | Timeof |, Average Dead
Lot number | dfvoots | er o"| exposure fos. ( ho Sumber | Revd | above and
used current sameag length | curvature only alec
ee Ra oe res 6 i 30 +1.1 4 6 °
ss an 6 iN 35 +2.0 5 6 °
Be ee 5 uy 40 +-1.4 3 5 °
EES CR ee rae 8 » 45 +o.8 5 8 °
Be ee ec 6 Vv 50 +1.5 3 6 °
es ick: 6 4 ke —o.I 2 5 I
Wie 6 v 60 —0.5 2 4 2
ne EE ESDP I2 v 65 =—o.5 7 9 3
tf | ee eee 12 s 70 —0.5 6 8 4
2 ae seer 6 v 70 —0.3 5 5 I
sy ea Gene tee 6 uN 75 —0.5 4 6 re)
ya | ena Bi ee 13 \ 80 —0.0 5 8 5
ee 10 uN 85 —0.6 2 3 7
sy ey Gee emt Io Vv 90 —1I.0 ° ° Io
10, 04, 96)... 21 4 90 —0.7 2 2 19
TABLE IV
CURRENT 0.3 MILLIAMPERE, 90 VOLTS; CRITICAL TIME 2 MINUTES, 30 SECONDS
Average
as Time of a vee ead Dead
Lot number aan of | exposure as cy pa above ee ag
; used current aii in length | curvature only
_— in mm.
Re eee 6 ‘ gO. | EES 3 6 .
Pee oe tee 6 120 | 0.5 2 * f
Rees Gee 6 120 Org 4 5 ‘
0. 16 nN 135 —0.5 ° 6 ro
ee 7 \ 155°} 8-7 2 3 4
Le Lk Bog ee 5 4 140 —o.6 I I 4
ne se ences 28 150. | —0.7 ° ° 28
WO eis: 10 \ 150 —1.0 ° ° =
a at, CUS epee 18 165 —0.9 ° ° 18

dead. When, however, the appearance of the extreme tip was watery
instead of chalky white and exhibited distinct turgidity, it was
regarded as evidence that the cells were in a living condition.
Associated with the latter condition was an increase in length and

128 BOTANICAL GAZETTE ; [SEPTEMBER

the curvatures mentioned. It is entirely possible for the upper
portion of the root (the region of rapid elongation and above) to be
dead and the tip to continue growth for a short time; in fact, many
such cases were found. It is well understood that it is difficult to

TABLE V
CURRENT 0.2 MILLIAMPERE, 70 VOLTS; CRITICAL TIME 4 MINUTES
Number | Direction | Time of Hips or} Number Dead ead
Lot number of roots of exposure | gain (+) | showing | above above and
used current poet 7 le = curvature only pa
SP eae 5 220 —o.1 I 5 °
Se i eas Io i 225 —0.6 ° 4 6
OF oe See ae ane Io } 230 —o.6 2 4 6
Se eae 2I 240 —0.4 ° a 18
Wei i 15 240 —0.7 ° ° 15
ey erry Bons Bae 8 \ 270 —0.9 ° ° 8
Booey cies 5 \ 270 —0.4 ° ° 5
eo ee pe ae 5 4 300 —0o.6 ° ° 5
_»
TABLE VI
CURRENT 0.15 MILLIAMPERE, 50 VOLTS; CRITICAL TIME 6 MINUTES,
I5 SECONDS
* Average Dead
Number | Direction | Time of loss (—) or] Number | Dead ap
Lot number of roots of hie! Sg gain ( rem nto above ee
used CHEM Toads _— curvature only also
Poe ey en 10 \ 300 —0.4 I 7 2
PS a 15 Bee en ca 15 ly 360 —o.8 4 6 9
Ay Oy TBS eee a 16 3 ae t 4 15 I
to-G7. 5.60. 8 h 370 —0o.4 I 2 6
Lee es 5 375 —o.2 ° ° 5
14, 39; 28s ca 15 375 O09 I I T4
» epee uae 10 375 OF ° ° io
Sibel pee 5 4 390 —<O. 5 ° ° "
16,75, 935. 34 15 390 —0.5 ° ° 15
3,69 6 ae 15 Y 405 —0.5 ° ° 15
OPIle Te) It { 405 —o.6 ° ° 11

set up a criterion of measurement as to when death takes place; in
fact, death has been called by some physiologists ‘(a reversible
process.” The writer believes, however, that these criteria are
sufficiently definite as used, and that they are scientifically sound.

1921]

MEIER—ROOT TIP

129

In determining the time factor, the current was kept at constant
amperage by sliding resistances for a definite time period, the time
being measured by a stop watch. The usual practice was to treat
seedlings in succession in the same manner (as to time and current),

TABLE VII
CURRENT 0.I MILLIAMPERE, 40 VOLTS; CRITICAL TIME 9 MINUTES
5 Average
Number | Directi ime of}, Number Dees
Lot number | of roots | of | *Posure |'rain(4)'| showing | above Parent

sed. current aieuniia yp curvature only alas
Se en eae 5 420 0.6 s 5 °
ft op os Spee acer Io 480 —o.2 I 6 4
4 LOTT Rea eae aiecal II 480 —o.2 ° 7 4
A ats, 8 \ 510 —0.7 ° z 7
VE 3s tee ere 9 525 —0.4 I 2 7
a Re” Seater 13 550 —0.5 ° 2 II
10, 14, 19, 22 20 540 =O.4 ° I 19
Se aes ah oe 5 570 gio & ° 2° 5
Se et 9 600 —0.6 ° ° 9
co Ee Io . 600 ~—0.7 ° ° id

TABLE VIII

CURRENT 0.05 MILLIAMPERE, 30 VOLTS; CRITICAL TIME PROBABLY BETWEEN 32 AND
35 MINUTES

Number | Direction | Time of hae Number | Dead
Lot number of roots of xP’ | gain (+) | showing | above net
used current | iinutes | 2 — curvature} only also
eee Sig Oe May 3 15 —0.5 ° 3 4
Ret + 18 —o.2 ° I °
eg ae ne: 7 1 25 —0.2 ° 3 *
Wee 5 \ 28 —o.r t * 4
eens 16 30 —0.3 3 3 13
oO niet Spe es OS 6 32 —0.4 I T 5
Bie ee 2 35 —0.5 ° sid ,
Sa en 4 { 35 —0.5 ° ks 4
CG a gs ah 2 q 40 0.2 ° - .
ce Re ere 2 h qo. | 0.3 ° ° -
EONS aS ah eee 2 50 ee ° ° .
such group (usually five), being designated as a “lot” in the tables.

Roots were exposed for a time, calculated from preliminary experi-
ments to be below that required to kill, then time of exposure
increased for next lot and so on until all were killed. When ninety

130 BOTANICAL GAZETTE [SEPTEMBER

per cent or over were killed at any particular combination of current
intensity and time, this was regarded as the death point. Death
points were determined for current intensities of 0.6 to 0.05 milli-
amperes as shown in the tables. Direction of flow of current is
indicated by arrows. When the current was applied with the posi-
tive electrode at the tip, the arrow points upward. Under “‘average
loss or gain”’ is given the loss or gain in length over measurement
taken just previous to exposure. Final measurement was always
taken twenty-four hours after exposure. Under the heading ‘‘dead
above only” is given the number in which the region above the first
4or5 mm. was killed. This effect was often noticeable as far back

1G. 3.—Current ge equa required to produce death in roots of 0.7-0.9
sq. mm. cross-sectional a

as the cotyledons. The last column gives the number in which the
entire root was killed. Thus it can be seen from the tables that
the critical time at 0.6 milliampere is fifty-two seconds; at 0.5
milliampere sixty-five seconds; at 0.4 milliampere ninety seconds,
etc. It should be stated that controls were planted with each lot,
and that all showed a decided increase in length, the increase vary-
ing from 12-19 mm. at the end of twenty-four hours.

Plotting the points as shown in the tables into a graph gives
the death curve (text fig. 3). With current of 0.05 milliampere the
death point was determined with great difficulty, due to length of
exposure required, which had a tendency to dry out the root. The
critical time seems to lie between thirty and thirty-five minutes.

1921] MEIER—ROOT TIP I31

It is not contended that the death curve is sharp and definite. As
the tables show, some roots were killed before the maximum was
reached. This difference is undoubtedly accounted for by the
variations in cross-sectional area of roots used.

CYTOLOGICAL

A rather definite cytological effect is produced in roots exposed
to the current just long enough to produce death. Roots exposed
for fifty-two seconds at 0.6 milliampere give a very similar picture
to roots exposed for two and a half minutes at 0.3 milliampere, or
any other point on the death curve. Similarly, roots exposed for
any fraction of the time required to produce death at any amperage
give a comparable picture with those produced by exposure for the
same fraction of time required to produce death at any other
amperage. This fact was established only after long experimenta-
tion, and until then no comparable cytological results could be
-obtained with various combinations of time and current. The
direction of current through the root had no influence except in
direction of migration.

Best results in fixing were obtained by various combinations of
Flemming’s fluid. Root tips immediately after treatment were
placed in the killing fluid. The usual processes incident to the
paraffin method were used, and the roots sectioned and stained in
saffranin-gentian violet. Satisfactory staining was quite difficult
to obtain, and the finer details of the treated protoplasts in most
cases were difficult to distinguish.

In a root exposed to the current just long enough to produce
death, the cells of the central cylinder back of the root cap show
fairly even distribution of cytoplasm, which, however, is coarsely
granular compared with the controls. Many cells show a distinct
migration of cytoplasm toward the positive electrode. It is in
the nuclei, however, that the effect is more noticeable. The
nucleolus may have been displaced in either direction, more cells,
however, showing displacement toward the positive electrode. A
majority of the nucleoli had become elongated in a direction at
right angles to the long axis of the root, similar to that shown in
fig. 3. The nucleolus frequently is elongated sufficiently to reach

132 BOTANICAL GAZETTE [SEPTEMBER

across the nuclear cavity. Other dense material within the nucleus
is in every case deposited in a crescent-shaped mass against the
nuclear membrane toward the positive electrode. This is shown
in some of the cells of figs. 3 and 5. The chromatin appears very
coarsely granular. Occasionally a cell is found in which a small
amount of this granular material is deposited against the side of
the nuclear membrane toward the negative electrode, leaving a
clear central space across which lies the much flattened nucleolus.

The cells of the central cylinder about 1 mm. from the cap
show shrinkage which is evident at the ends of the cells, but not
laterally.

In the cortex of the first millimeter the cells show greater effect
than in the central cylinder. The cytoplasm in these cells is in
nearly every cell definitely aggregated against the wall toward the
positive electrode. The nucleolus no longer lies across the nuclear
cavity, but has migrated with the chromatin toward the positive
electrode (fig. 8). The nuclear cavity is no longer spherical but .
egg-shaped, with the smaller end toward the anode. Chromatin
and nucleolus are packed into the small end, and seem to have
forced distention of the nuclear cavity. Frequently fine granular
threads radiate from this mass toward various points in the periph-
ery of the nucleus, as shown in figs. 8 and 11. This bears a strik-
ing resemblance to fig. 12, pl. 18, of Morrier’s paper (16). The
nucleolus in most cells at this stage cannot be distinguished as a
separate body from the chromatin. _

It is in dividing cells that the greatest effect of the current might
perhaps be expected, yet such is not the case. Migration does not
take place at all in a cell in the process of nuclear division in either
cytoplasm or chromosomes. Staining of division figures is poor,
and in most cases presents a blurred picture in which the chromatin
has the appearance of having melted together. Cells with nuclear
division are shown in figs. 2 and 3. This blurred condition is
characteristic of all division figures, no matter at what stage. All
parts of such a cell usually stain a deep red with saffranin. The
absence of migration should be expected in such cells from results
found by Kite (13) and CHampers (4), who both found the pro-
toplast during division in a very viscous state, in the form of a gel.

1921] MEIER—ROOT TIP 133

KireE states that when such a protoplast was cut into, the pieces
retained their shape definitely and behaved distinctly as a gel.

In the region of rapid elongation in both cortex and central
cylinder, 3-5 mm. from the cap, the cytological picture reveals
little effect compared with the extreme tip. The cytoplasm shows
no migration whatever, although it is more coarsely granular than
that of the controls. The nucleolus retains its form and position,
while the chromatin is aggregated in a crescent-shaped mass against
the nuclear membrane toward the positive electrode in a majority
of cells, in a few toward the negative electrode. In some cases,
however, the entire nuclear material is displaced within the cavity
(fig. 6), and in a few cases even the entire nucleus lies in a dense
mass against the wall toward the positive electrode, a phenomenon
not met with at this exposure in cells nearer the cap. Shrinkage is
quite evident in the region of rapid elongation.

The root cap rarely shows any displacement of either cytoplasm
or nucleus, doubtless largely due to the fact that the moist kaolin
of the electrode is a better conductor than the root, and so very
little current passes through the cap.

The first noticeable cytological effect of the current is produced
on exposure of approximately one-tenth of the time required to
produce death, and the first visible reactions occur in the cortical
region about 1 mm. above the cap. Such cells show large vacuoles
in the end toward the negative electrode, and the cytoplasm appears
slightly more granular than in the controls. The chromatin at this
stage is beginning to migrate toward the positive electrode. The
nucleolus lies in its normal position, but soon after one-tenth of
time exposure begins to show the flattening previously described.
At this stage the region above the first millimeter shows nothing
abnormal, neither do the cells immediately behind the central
portion of the root cap. The effect of the current is progressive
and the results are cumulative. At one-half of the time for death
point, the nucleolus flattens and the cytoplasm definitely begins
to migrate. With an exposure of three-fourths of the time for
death the nucleolus and chromatin have migrated toward the
positive electrode, the cytoplasm being very coarsely granular and
exhibiting a greater amount of migration than in the previous

134 BOTANICAL GAZETTE [SEPTEMBER

stage. The picture at death point has already been described
in detail.

If the current is continued for a longer period than is necessary |
to produce death, all protoplasmic contents, especially the cortical
cells of first 3-4 mm. of tip, are aggregated in a dense mass against
the cell wall toward the positive electrode, as shown in pl. II, also
partially shown in figs. 9 and to.

Discussion

Within thirty seconds after the current is applied, the resistance
in the circuit falls considerably. The resistance, however, was
always kept constant by means of the sliding rheostats. Coincident
with the drop in resistance, the tiny droplets of liquid appeared on
the surface of the root in the region of rapid elongation and above.
This suggests increased permeability of the protoplasts and of the
cell walls to liquids of the cell sap, and further suggests increased
freedom of movement of particles in the sap or cytoplasm or both.
The consequent loss of turgidity and shortening of the root sub-
stantiate this view.

It is most interesting to find that the greatest visible effect of
the current is not in the region of most rapidly dividing cells, but
slightly farther from the tip. This suggests that the protoplasm
of these cells exists in a much more viscous state than in cells
farther from the tip. The lack or presence of free ions would
influence conduction of current. It is possible that free ions exist
in increasingly greater number with the absorption of water from
the primordial meristem to the region of greatest elongation. If
this assumption is true, we would expect least effect of current in
the primordial meristem, where the cytoplasm would be viscous
and behave as a gel, and a greater effect where the cytoplasm
became more nearly semi-fluid, and least effect where the free ions
of the cell sap conducted the current almost altogether. This
assumption agrees with the facts, for the least (or no) migration
occurs in the cells with large vacuoles.

In no preparations made could any basis be found for HarpDy’s
(9) statement that the cytoplasm migrates to the wall, loses its
original charge, gains one of opposite sign, and then migrates toward

1921] MEIER—ROOT TIP | 135

the opposite end of the cell. This statement, however, may apply
to the chromatin. No theory is advanced as to why neighboring
cells behave variously in this regard. The relative hydrogen ion
concentration of the different parts of the cell no doubt plays a
large part with reference to its reaction to the current. The
assumption is generally made that cytoplasm is weakly alkaline.
This conception is probably based on the reaction of the cell sap;
nevertheless we have evidence that the migration of the protein
constituents in the cells is toward the positive electrode. Likewise
it is in accord with Harpy’s (9) results in treatment of a derived
albumen, first with acid, then alkali, and a consequent change in
direction of migration as previously stated. That the chromatin
under some conditions bears a positive charge seems to be suggested
by my own experimental evidence. That the migration of proto-
plasmic particles, as influenced by the current, is due to the particu-
Jar electrical charge of the constituent colloidal particles also
seems probable, and would suggest that the cytoplasm carries (in
the roots of the plants used in this study) always a negative charge.

Summary

1. A method of subjecting roots in moist air to the direct
electric current has been devised which makes it possible to control
and accurately measure the current actually flowing through the
root. There is no evidence that under such conditions roots behave
differently from those in soil or liquid if subjected to the same
current intensity.

2. Combinations of current intensity and time factors have been
determined for producing death of the cells of roots, and the death
curve plotted.

3. Cytological preparations of treated roots show a migration
of cell contents (with few exceptions) toward the positive electrode.

4. The migratory effect (transfer of material) is not the same
for all regions of the root. With one-tenth of time of death current,
the cells immediately back of the root cap show little effect, those
a little older (r mm. back) greatest effect, and the cells with large
vacuoles no or little effect as to cytoplasm.

136 BOTANICAL GAZETTE [SEPTEMBER

5. It is suggested that, with addition of water, more free ions
may occur to conduct the current; that the protoplasts of the
primordial meristem are in a state of gel.

6. It is further suggested that the difference in true acidity,
H-ion concentration of various protoplasts, may account for
occasional different behavior of adjacent cells.

7. The theory of electrophoresis probably accounts for the
migration phenomena, assuming that the constituent colloidal
particles of protoplasm bear an electric charge.

8. Assuming an electric charge carried by such particles, it
would follow that the particles of the cytoplasm of the cells of the |
roots of the Canada Field Pea bear a negative charge, and that the
chromatin particles, in some cases only, may bear a positive charge.

The writer takes pleasure in extending thanks to Dr. W. G.
MARQUETTE and Professor R. A. HARPER for kindly suggestions and
criticism freely given throughout the progress of the work. The
work was done in the laboratories of the Department of —
Columbia University, New York City.

SYRACUSE UNIVERSITY
Syracuse, N.Y.

LITERATURE CITED

. Amici, G. B., Osservazioni sulla Circulazione del Succhionella Chara. Mem. .
gor ene Soc. “Ttal. VIII. 2: Med. 1818 (quoted from BECQUEREL).

2. BECQUEREL, A.C., Influence de I’électricité sur la circulation du Chara.
Compt. Rend. 5:784-788. 1837.

3. CaRrtcREN, O., Uber die Einwirkung des constanten galvanischen Stromes
auf niedere Organismen. Archiv Anat. und Physiol. 1900 (pp. 49-75).

4. CHAMBERS, R., Changes in protoplasmic consistency and their relation to
cell division. Jour. Gen. Physiol. 2:49-68. 1919.

5. Corenn, A., Uber ein Gesetz der Electricitatserregung. Ann. Physik und
Chemie 64:217-232. 1898

6. Date, H. H., Galvanotaxis and chemotaxis of ciliate infusoria. Jour.
Physiol. 26:291-361. rgrr.

7. Du Bots-Reyomonp, E., Uber die innere Polarisation pordser mit Elektro-
lyten getrinkter Halbleiter. Berlin Akad. Wiss. 1856 (pp. 450-468) and
1860 (pp. 846-906). :

1921] MEIER—ROOT TIP 137

8. Harpy, W. B., The coagulation of proteid by electricity. Jour. Physiol.

be
°

Lal
-

24:288-304. 1890.
e on difference in ha potential within the living cell.
Jour. Physiol. 47:108—111.

19
. HetmuHortz, H. von, Studien ahed elektrische Grenzschichten. 'WHIEDE-

MANN’S Asada 7:337. 1879; also Mem. Physical Soc. London I:I-42.

‘ tienen, T., Uber die Bewegung fester, in Fliissigkeiten suspendierter

Kérper unter hen Einfluss des eélektrischen Stromes. ICHERT un
pu Bors-REymonp Archiv. Anat. und Physiol. 1860 (pp. 673-687).

er die in den Zellen der Vallisneria spiralis stattfindenden
akcipsiiaiet heicaaaben Studien Physiol. Inst. Breslau 1861 (pp. 87-
109).

. Kite, G. L., Studies in the physical properties of protoplasm. Amer.

Jour. Physiol. 32:146-164. 1913

Ktune, W., Untersuchungen iiber das Protoplasma und die Contractilitat.
1864.

Lite, R. S., On difference in the direction of the electrical convection of
certain free cells and nuclei. Amer. Jour. Physiol. 8:273-283. 1903
Mortirr, D. M., The effect of centrifugal force upon the cell. Ann.
Botany 13:32 eatin t 99.

PERRIN, J. (Electricité)—“Examen des = qu déterminent le
signe et la grandeur de |’ par contact.”
(Note de M. JEAN PERRIN, présentée par M. Mascart.) Compt. Rend.
136:1388-1391. 1903.

Picton, H., and Linper, S. E., Solution and ee Jour.
> Soc. ri 148. 1892; 67:63. 1895; '71:568. 1897 :1906. 1905.
QuincxE, G., Uber die Fortfiihrung materieller Thelen durchattiaes:
der ea Pogg. Annalen IV. 23:513-508. 1

Reuss, F. F., Mein. Soc. Imp. Nat. Moscou 2: oe 1809 (quoted by

- VERWORN, M. , Die polare Erregung der Protisten durch den galvanischen

Strom. Petvon’e Archiv. 5:1-36. 1889; 46:267-303. 1890; 62:415-
450. 1896; 65:47-62. 1897.

Wiepemany, G., Uber die Bewegung im Kreise der geschlossenen galva-
nischen pa ‘Pons. Annalen 87:321-352. 1852.

EXPLANATION OF PLATES II, ll
PLATE II
Longitudinal sections of root tips: magnification shown by scale; smallest

spaces equal to o.or mm.; XII0.

A.—Root exposed to curtent of 0.4 milliampere for one e and a half minutes;

Positive electrode at tip.

138 BOTANICAL GAZETTE [SEPTEMBER

B.—Root exposed to current of o.2 milliampere for four minutes; nega-
tive electrode at tip.

C.—Control, not exposed to current.

PLATE II

Cells from various portions of roots exposed to current, and from controls;
magnifications for all figures approximately 580 diameters, with exception
of fig. 8, about 500 diameters, and fig. 10, 550 diameters; all photomicrographs
mounted so as to have positive electrode below.

Fic. 1.—Normal cells (not exposed to Seats 8-10 mm. from tip in
cortex.

FIG. 2. els about 1 mm. from tip in central cylinder from root exposed
to current of o.5 milliampere for sixty-five seconds; in the lower right hand
ge dividing

gaa ey Hoa. cortex of root exposed to current of 0.2 milliampere for
one he this being one-fourth time required to kill root at this amperage.

Fic. 4.—Normal cells from cortex about 3 mm. from tip.

Fic. 5.—Cells of central cylinder about 8 mm. from tip; root exposed to
current of 0.6 milliampere for twenty-five seconds.

Fic. 6.—Cells from cortex about 10 mm. from tip; root exposed to very

i ).

G. 7.—No cells from cortex about 1 mm. from tip.

Fic. 8.—Cells from cortex about 1 mm. from tip of root exposed to current
of 0.6 milliampere for forty seconds.

Fic. 9.—Cells from cortex about 4-5 mm. from tip; cytoplasm and nuclei
also displaced; current of 0.3 milliampere for two and one-half minutes.

1G. 10.—Same as fig. 9 but exposed to current only one and one-half

minutes.

‘Fic. 11.—From same region as fig. 8

il wl ae UT APU

PLATE if

BOTANICAL GAZETTE, LXXII

MEIER on ROOT TIP

BOTANICAL GAZETTE, LXXII PLATE Ill

MEIER on ROOT TIP

CHEMISTRY OF AFTER-RIPENING, GERMINATION,
AND SEEDLING DEVELOPMENT
OF JUNIPER SEEDS

CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 284

DEAN A. PAcK
Introduction

In a previous paper the author (17) reported the microchemical
and physical changes accompanying the after-ripening, germination,
and seedling development of juniper seeds. This work was under-
taken with the idea of studying the physiological and chemical
changes occurring in the fats during the after-ripening and the
seedling development of seeds of Juniperus virginiana.

Historical

As early as 1842 Dr Saussure (3), while studying the germina- —
tion of hemp, madia, and rape seeds, discovered two important
results that accompany the germination of oily seeds. He con-
cluded that oily seeds during germination absorb a larger volume
of oxygen than the volume of carbon dioxide given off, and that
the percentage of reserve oil decreases and the percentage of sugar
increases during germination. Part of De SAUSsURE’s work was
later confirmed by the investigations of HELLRIEGEL (g) and others.

SACHS (20) in 1859 studied the transformation of oil in many
seeds, and concluded that starch was directly derived from oils.
PETERS (19) held this same view, but FLeury (4) denied the con-
stant appearance of starch, and stated that sugar appeared first.
The latter investigator was the first to note the probable appear-
ance of organic acids during germination.

Mintz (16) was the first to discover the presence of free fatty
acids in germinating oily seeds. While working on rape, poppy,
and radish seeds he found that the oil gave rise to free fatty acids.
He also noted that this free fatty acid increased several fold
during germination. Although the presence of glycerine was not
139] [Botanical Gazette, vol. 72

140 BOTANICAL GAZETTE [SEPTEMBER

demonstrated, he concluded that the oil was split up into free fatty
acid and glycerine.

GREEN (7), while investigating the reserve products of Ricinus
communis seeds during germination, discovered the enzyme lipase.
He proved that this enzyme was capable of splitting the glycerides
of this seed into glycerine and fatty acid. This investigator con-
cluded that glycerine gave rise to sugar, while the fatty acids gave
rise to vegetable acids. He also demonstrated the presence of a
trypsin-like enzyme, which digested proteids. In a later paper
(8) he continued the same investigation and worked especially on
the lecithin and sugar content. The lecithin was thought of as
being derived from the oils, phosphatic globoids, and proteins.
In this paper he discussed the improbability of oa being formed
from glycerine.

In 1895 LEcLERC DU SABLON (13) investigated many seeds and
finally concluded that saccharose or a nearly related sugar was
derived from oils without the glycerine being set free, as in ordinary
saponification. MILLER (15), in his studies on the sunflower,
records the gradual disappearance of reserve oil and protein mate-
rial from the cotyledons, with the increase of sugar and protein-free
nitrogen in the hypocotyl and roots. In 1912 IvANow (10). fol-
lowed the transformation of the oils in seeds during germination.
He chose for his work seeds having saturated fatty acids, and
others having unsaturated fatty acids. The unsaturated fatty acids
were found to be transformed first, and later the saturated fatty
acids were used. He ascribed the fall in the iodine number of the
fats to the more rapid transformation of the unsaturated fatty
acids to carbohydrates, and not to the formation of acids of shorter
chains. :

KosseEL (12), as early as 1891, believed lecithin to be present
in all protoplasts. SToKLasA (21) states that the phosphatides of
rape seeds during five days’ germination increased from 0.45 to
5.22 per cent. The dry beet seed with a phosphatide content of
0.45 was found to contain 1.78 per cent after nine days’ germination.
CzaPEK (2) quotes data from Scuvutze and his school, also others,
showing the general distribution and percentage of phosphatides
in plant tissues. FRANKFURT (6) in 1894 studied the seeds and

Ate

ii natalia ctenitmenn™

1921] PACK—JUNIPER SEEDS 141

seedlings of the sunflower, and found that glutamin and asparagin
increased during germination. PALLADIN (18) in 1896 stated that
an increase of the proteins indigestible in gastric juice (nearly
proportional to the amount of nucleo-proteins) accompanied the
germination of wheat in darkness. ZALIESKI (22) in rg11 reported
the general appearance of nucleo-protein in plant tissues. He also
found an increase of nucleo-protein with the germination of wheat
and corn seeds.

Investigation
CULTURE METHODS

After the seeds had been prepared, as described in an earlier
paper (17), they were placed on moist filter paper in Petri dishes
and subjected to a temperature of about 5°C. in darkness for after-
ripening and germination. Distilled water was added at intervals
to keep them moist. The changes occurring had to do with the
reserve material already in the seed. The after-ripened seeds and
seedlings were kept under these conditions until being prepared for
analysis. Analyses were made at three different stages: dry seeds,
after-ripened seeds, and late seedling development.

Dry sEEps.—The hard coats were removed from the dried seeds
before preparing them for analysis. In this, as well as in the
following stages, the embryo and endosperm (or more exactly, the
nucellus, megaspore membrane, and all parts surrounded by these
two structures) were the parts analyzed.

AFTER-RIPENED SEEDS.—The seeds were found to require 100
days’ storage in a germinator at about 5°C. for after-ripening (or
to become ready for immediate germination). The seed at this
particular period has already split open the hard coat, and the
hypocotyl is breaking through the nucellus. It was at this time
that the after-ripened seeds were removed from the hard coats and
prepared for the analysis.

DEVELOPED SEEDLINGS.—It required 35 days at 5°C. for the
after-ripened seeds to become developed seedlings, which were
between 3 and 4cm. long. The cotyledons were extended and
free from the old endosperm, nucellus, megaspore membrane, etc.
These latter structures were collected and put with the seedlings

pwned

142 BOTANICAL GAZETTE [SEPTEMBER

so as to have comparable analytical results. The hard coats were
separated and discarded, just as in the collection of the seed material.

ANALYTICAL METHODS AND RESULTS

The material for analysis was prepared according to LOWEN-
STEIN (14) and MILter (15), except for slight modifications. The
collected seeds and seedlings were thoroughly ground with 95 per
cent alcohol in a mortar; then the material was transferred to
evaporating dishes and the alcohol evaporated. After thus treat-
ing the material three times with 95 per cent and twice with absolute
alcohol,*it was dried in a vacuum at 75°C. for one hour. The
material was then powdered and placed in the desiccator until
analyzed. When analyzed the material was in perfect condition,
and showed no signs of oxidation.

The method followed in the analysis was outlined by Kocu (11).
As it was necessary to make both fat and protein analysis on the
same sample, the acid precipitation of the lipoid fraction, as earlier
described by Kocu, could not be used because of possible protein
hydrolysis. The lipoids, therefore, were extracted by an 18-hour
continuous extraction with hot absolute anhydrous ether. Cal-
cium chloride tubes were used to protect the material from moisture
during the extraction. Lipoid or ether soluble material is
referred to as F;. The whole of the lipoids were not dried to get
the true weight, because of the danger of oxidizing the unsaturated
compounds. This lipoid weight was derived by subtracting the
weight of the dry lipoid-free material from the original dry weight.
Such a change made it possible to analyze the lipoids at once and
avoid oxidation (table II); then the lipoid-free material was
extracted with hot 50 per cent alcohol for 12 hours. This 50 per
cent alcohol soluble material is indicated as F,, or extractives.
These extractives were dried to constant weight in vacuum, dis-
solved in hot water, and portions taken for the analysis. The 50
per cent alcohol insoluble material (or F;) was dried in vacuum,
weighed, powdered, and portions taken for analysis (table IV).

Table I gives some general data. The amount of water and
solid material found in the air-dry seeds, after-ripened seeds, and
seedlings at the time the material was prepared for analysis, is

1921] PACK—JUNIPER SEEDS 143

given as percentage of seed weight with hard coats removed. Total
nitrogen is given as percentage of total dry substance and was
obtained by the KJELDAHL method. The analysis of chlorophyll

t
could not be attempted. The amount of chlorophyll present,
however, is given as percentage, and was estimated from the depth
of color, considering the chlorophyll content of the seedlings as
roo per cent.
TABLE II

Liporps (F;)
Dry SEEDS sacar rato SEEDLINGS
MATERIALS
a b a b a b
Total lipoids as percentage total
WEIRD 6a eye ee 53.60 | 53.69 | 43-93 | 44-01 | 11.72 | 11.00
ar pees as percentage total
Oy Weigut. |... fi 5.23] 1.221 2.80) 2.84] 2.36] 2.37
Acid tae as percentage ether
WRU ey yy ee ae L.97 1.90} 5.68] §.09 | 27.75 | 28.12
Saponification number........... 174.7 |172.3. |178.3 |180.0 |126.0 {127.1
SOUP PUD. a. 6 ess vn ccs 133-6 |135.0 [132.1 |131.0 |121.4 [122.0
Neutral fats as percentage ether
MOEN oe ic aye oi aw 95-73 | 95-82 | 87.93 | 88.46 | 52.07 | 50.0%
Penta of P in total dry idee? 0.03 | 0.03 | ©.109] 0.110} 0.092) 0.095
Percentage N as percentage of
otal Wein 6 O Of bial. Oh tia se, O08 Ji.
Percentage of increased weight due}
to probable O, absorption. .... 6.0 1.545: Moe ee. et ae:

In tables II, III, and IV the amount of substance found has
been given as percentage of the total dry substance unless other-
wise stated. Thus in table II the acid value, saponification number,
iodine number, and neutral fats were determined for the total lipoid

144 BOTANICAL GAZETTE [SEPTEMBER

fraction. The percentage of phosphatide was estimated from the
lipoid; P times the factor 25.77. Wuj’s iodine solution was used
in the determination, of the iodine number. No direct nitrogen
determination was made on the lipoid fraction. The percentage
of nitrogen given was found by subtracting the extractive and
protein nitrogen (tables III and IV) from the total nitrogen given
in table I. Table II also gives the percentage of oxygen taken up
by the lipoid material under artificial oxidation.

TABLE III

EXTRACTIVES (F2)

SEEDLINGS
PERCENTAGES OF TOTAL
DRY WEIGHT
a b c a b c ‘ b c
Total extractives. . O.G8 PP O.s0) fis 94 las be |. (84002 [94. §0];..--
Total gens 6:13 | @.2¢ 1.0 $0125 f 220 < ;
nia nitrogen. .| 0.0004] 0.0004]... .| 0.0004] 0.0003}....| O.CO0I]..... es
Amino acid nitrogen.| 0.04 | 0.05 |o.04| 0.27 | 0.25 |o.30| 0.92 | 0.95/0.93
Reducing sugars after]
hydrolysis........ 1.27 %.30. {%.25| 1-66 1.80. |1.88] 7.49 7.4317-55
Direct reducing
sugars........... Traces fe ceka ve SE OOF a. O108)-2:5395° | 3: 3418.37
Reducing sugars
after removal of
NING ois es bees RYACRS be pase bss OG. Pe Ee ade cates es oe
Pentose reaction. ape Pee ve ST RAPKORIS 3. 2) - ee ia aed Barenas,
marked .
Unaccounted for ma-
terial (organic
WON is 2 atin ha ee pee ed Adsseass PO Ey ae ee cane

Table III gives the extractives as percentage of total dry
substance. The total nitrogen was determined by the Bock and
BENEDICT (1) modification of the Fotrn-FarMER (5) procedure.
Ammonia nitrogen was determined by the same procedure after
aerating under diminished pressure a large part of the extraction
solution made slightly alkaline and collecting the ammonia in

ilute HCl. The undistilled material was neutralized with acetic
acid, concentrated, and used for van Slyke amino nitrogen deter-
minations. A third portion was used for the sugar determinations.
The tannins were removed with pure casein. Both after-ripened
seeds and seedlings gave indications of pentose.

1921] PACK—JUNIPER SEEDS 145

The proteins, polysaccharides, etc., are given in table IV as
percentages of total dry substance. The protein nitrogen, which
is stated as percentage of protein, was determined by the KJet-
DAHL procedure. Polysaccharides were determined by the Mon-
SON-WALKER and BERTRAND method. This material gave very
marked pentose reactions. The cellulose was not determined
as such,

TABLE IV
PROTEINS, POLYSACCHARIDES, ETC. (F3)
Dry SEEDS AFTER-RIPENED SEEDS SEEDLINGS
PERCENTAGES OF TOTAL DRY WEIGHT
a b a b c a b
ela pte eee etc. .} 30:73} 30.00) 40.83 | 40.43) .252 2. 54-25 | 54-40
Total proteins (F; eo eee 34.21] ..34.10 — os 27 OSs ys 22.32: 1:33.90
Total As sugars oan 0.0 0.0 0.23] ©.19] 14.91 | 14.79
Indications of pentoses....... 6:0 106.0 Seco Nb a Pala ne CY bt
marked
Discussion

These results force upon one’s attention the great constructive
changes as compared with the destructive changes. The major
fractions seem to be well accounted for. Such a condition can only
be understood when one considers that these results deal with a
seed that requires long continued after-ripening and germination
at a very low temperature. Although the seed material was kept
at a temperature of about 5°C., the constructive metabolism went
on at a rapid rate. The digestion of storage ae and gplscomilg was
accompanied by the synthesis of many f

pounds. The rate and extent to which these changes were carried
on even at 5°C. prove the power and efficiency of enzyme action.
This low temperature, by retarding respiration, reduced the com-
bustion of materials to a minimum, and thereby favored the
accumulation of formative materials in the cells. This accumu-
lation of cell building and cell active materials, together with the
culmination of enzymes, probably leads to the after-ripening of
dormant organs.

The lipoids decreased 9.7 per cent during after-ripening, and
32 per cent during the seedling development. It will be seen that

146 BOTANICAL GAZETTE [SEPTEMBER

the neutral fats sustained this loss. The respiration occurring
during the after-ripening period amounted to only 2 per cent, while
during the seedling period it amounted to about 5 per cent of the
total dry weight. This small amount of material used by the
respiration compared with the large amounts of formative, storage,
and structural material, high in oxygen content, made from the
apparently small amounts of fats, low in oxygen content, will easily
account for the low respiratory quotient reported in an earlier
paper (17) for these seeds during germination.

The phosphatides more than doubled during the after-ripening
process. Glycerine and fatty acids were supplied by the hydrolysis
of fats, while phosphoric acid and nitrogen-containing complex were
probably derived from inorganic phosphorus and the protein
hydrolysis which accompanied the after-ripening. A slight decrease
in the amount of phosphatides occurred during seedling develop-
ment. This decrease could represent the phosphoric acid necessary
for the formation of the nucleic acid, which was constructed at
this period.

The acid value of the ether extract increased during both after-
ripening and seedling development. The iodine number decreased,
while the saponification increased slightly without a marked
appearance of carbohydrates. Such a condition would probably
accompany the breaking up of long carbon chains into shorter
chained compounds. The increased fall in the iodine number
during the seedling development was due perhaps to the more
rapid transformation of unsaturated fatty acids to carbohydrates
(x0). This carbohydrate accumulation during seedling develop-
ment amounted to 20 per cent (tables III and IV). The saponifi-
cation number reached a minimum value for the seedlings,
indicating a large percentage of long chained fatty acids. This is
accounted for by the large percentage of phosphatides in the
seedling lipoids. It appears that these values change materially
in the same tissues with different stages of development.

Dry seed and after-ripened seed lipoids were made to take up
respectively 9.9 and 11.1 per cent of increased weight due to prob-
able oxygen absorbed by artificial oxidation. There was a slight
increase in the reducing power of the lipoids during after-ripening.

1921] PACK—JUNIPER SEEDS 147

Under the same conditions the seedling lipoid material increased
in weight only 3.1 per cent due to oxygen absorption.

Of considerable interest is the increase in extractives with
after-ripening and seedling development. This is represented by
increasing amounts of amino acid nitrogen, and other forms which
probably represent amides, peptides, nucleic acid derivatives,
alcohols, etc. It also represents increased amounts of various
sugars, and very probably organic acids. The ammonia nitrogen
value did not change during after-ripening, although it did decrease
during the seedling development. This decreasing amount corre-
sponds to the amount of nitrogen required during this same period
to build the chlorophyll. As ammonia plays such an important
part in the synthesis of proteins (amino acids), however, it is
probable that this decrease is of no significance and that
amounts fluctuate. In connection with this it is evident ho
some proteins, having carbohydrate groups, were rebuilt during
the after-ripening and especially the seedling development. Amino
nitrogen, van Slyke method, increased about sevenfold during the
after-ripening period, and over threefold again during the seedling
period (table III). The Formol titration on similar lots of seeds
showed a like increase of amino acids during the after-ripening
period. The ratio of the amino nitrogen to the total nitrogen of
F, is as follows: dry seeds one-third, after-ripened seeds one-third,
and seedlings one-half. This could mean the formation of shorter-
chained amino compounds or the further digestion of peptides,
proteoses, or peptones. The increasing amount of non-amino
nitrogen during after-ripening and seedling development shows
the accumulation of other nitrogenous compounds. This is very
probably represented by nucleic acid, peptides, peptones, amides,
and other extractives.

Although the sugar formation was very meager during the
after-ripening period, it reaches noticeable proportions during the
germination and seedling development. Table II shows a o.5 per
cent increase of reducing sugars, after hydrolysis, for the after-
ripened seeds. This included a few hundredths per cent of direct
reducing sugar. It is evident that nearly all of the reducing sugar
_ of the dry and after-ripened seeds is tied up with the tannins.

148 BOTANICAL GAZETTE [SEPTEMBER

The dry seeds gave no pentose reactions, while the after-ripened
seeds and seedlings gave marked reactions. During the seedling
development the percentage of sugars increased manyfold.
Comparing the amount of total extractives and the sum of the
analyzed fractions, it will be seen that there is considerable material
unaccounted for. After adding an average percentage for ash,
however, the 6.68 per cent of extractives for the dry seeds is nearly
all accounted for. After adding the same amount for ash in the
after-ripened seeds and the seedlings, there remain respectively
3 and ro per cent of the extractives unaccounted for. It is evident
that this material is not proteins or, much less, decomposition prod-
ucts of the same. Such an explanation would require a protein
factor of ten or more. It could not be due to an increase of‘ash
because the seeds were kept in distilled water cultures. The
sugars by no means account for this unknown material, and a
possible explanation is the presence of organic acids. A review of
the analytical results of tables II, III, and IV also shows that there
is no other way to account completely for the disappearance of so
much fat. It is evident, therefore, that at least part of the fatty
acids were oxidized to other organic acids. In the course of the
analysis (when F, was neutralized for ammonia distillation) it was
found that the extractives for dry after-ripened seeds and seedlings
all gave an acid reaction. No acid had been used thus far in the
analysis, and this acidity was evidently due to acids in the tissues.
_ The extractives of the dry seeds were distinctly acid, while the
extractives of the after-ripened seeds and seedlings were very acid.
It was also noted that more N/1o NaOH was used to neutralize the
seedlings than either the dry seeds or after-ripened seeds. These,
with previous results, point to the accumulation of organic acids.
Table IV shows an increase of the protein polysaccharides
fraction during after-ripening and germination. There was a
decrease in the proteins with an increase of starch. During after-
ripening, however, there was a 6 per cent decrease of proteins with.
only a 0.2 per cent increase of starch. Of course much of this
protein material appears in F, as amino acids and other nitrogenous
compounds, Moreover, some proteins after hydrolysis and deami-

1921] PACK—JUNIPER SEEDS 149

nation very probably gave rise to sugars and acids or were respired.
The pentose reactions indicate the rebuilding of proteins with
carbohydrate groups. During the germination and seedling devel-
opment the proteins were hydrolyzed to give rise to the amino
acids and nitrogenous compounds of F., with the formation of some
carbohydrates. From the amount of starch (table IV) and sugars
(table III) appearing in the seedlings and the carbohydrates
required for cellulose structure, it is evident that not only the
proteins but still more the fats contribute to the formation of these
materials. From the constant quantity of nitrogen in the analysis
and the fact that no nitrogen compounds were added, it is evident
that the chlorophyll nitrogen was derived from other nitrogenous
compounds.
Summary

A review of these results, together with the changes reported
in the previous paper (17), give an idea of the many changes
accompanying the after-ripening of dormant organs. These
changes are represented by the accumulation of cell building
materials: acids, phosphatides, active reducing substances, soluble
sugars, pentoses, amino acids, soluble proteins, and other nitro-
genous compounds; the accumulation of enzymes; the dispersion
of materials; and the transformation of storage materials. This
rapid accumulation of simple plastic cell materials coupled with
minimum respiration and combustion of materials probably forces
the dormant organs to activity. One thus sees the awakened
active organ as a very unstable structure made up of many unstable
compounds. If these changes are not the basis of the after-
ripening process, they are found to accompany the after-ripening
process.

I wish to thank Dr. Wr~tt1AM CROCKER and Dr. FRED CONRAD
Kocu for their kind aid and criticism of this work.

U.S. DEPARTMENT OF AGRICULTURE
Satt Lake City, UTAH

150 BOTANICAL GAZETTE |SEPTEMBER

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14. LOWENSTEIN, A., The ae determination in commercial products of a
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annuus. Ann. Botany 24:693-726. IgIo.

16. Mtnvz, M. bat la germination des graines oleagineuse. Ann. de Chimie
iV. aai ays.

17. PACK, = A., “The after-ripening and germination of Juniperus seeds.

$130-6o. 1921.

18. Pun W., Recherches sur la correlation entre la respiration des
plantes et les substances azotées actives. Rev. Gén. Bot. 8:225-248.
8

1806.

9. Peters, Ep., Zur Keimungsgeschichte des Kiirbissamens. Landwirthsch.
Versuchs-Stat. 3:I-19. 1861

20. Sacus, J., Uber das Auftreten der Starke bei der Keimung élhaltiger
Samen. Bot. Zeit. 1859:177-188. 1

21. STOKLASA, J, Die Assimilation ies Lecithins durch die. Pflanze. Sit-

ber. K K. Akad. Wiss. Wien 104':617, 712-722. 1895

22. ZALIESKI, W., Uber die Rolle der Nucleoproteide in pt Pflanzen. Ber.

Deutsch. pak Gesellsch. 29:146-155. 1911.

LEAF- TISSUE PRODUCTION AND WATER CONTENT IN
A MUTANT RACE OF PHASEOLUS VULGARIS
J. ARTHUR HARRIS
Introductory

Ina specading paper’ it was shown that the survival of the bean
plant is in a measurable degree dependent upon the morphological
characteristics of the seedling. In 1915 a series of investigations
was undertaken to determine, if possible, something of the proximate
causes of the differential death rate. It was also hoped that some
light would thereby be thrown upon the proximate causes under-
lying the occurrence of teratological variations in the seedlings of
Phaseolus. In undertaking this work the assumption seemed
justified that if innate physiological conditions which might affect ,
growth be associated with morphological variations, some influence
of these factors should be recorded in the size or other characteristics
which result from the relatively enormous expansion which the
organs of the embryo undergo in the course of germination and the
establishment of the seedling.

A first study? demonstrated. that ‘tatoos seedlings in
general show a lower capacity for the development of primordial
leaf tissue than do normal seedlings grown under as nearly as pos-
sible identical conditions. The data then available indicated that
a reduction of the volume of primordial leaf tissue is associated
with abnormalities of all the abnormal types studied, but that the
type of variation influences in some degree the amount of reduction.
In these first experiments the conclusions were based on primordial
leaves only. The use of such leaves has the obvious disadvantage
that they are formed in the seed, and undergo merely an enormous
expansion (and possibly a little differentiation) in the germination.

* Harris, J. AntHuR, A simple demonstration of the action of natural selection.
Science, N.S. 36:713-715. 1912.

7. Studies on the ter
The development of the peace leaves in Ca bean seedlings. Genetics
1:185-196, 1
151] [Botanical Gazette, vol. 72

152 BOTANICAL GAZETTE |SEPTEMBER

of the seed and the development of the plantlet to the stage at
which measurements were made. Since the development of the
primordial leaves during the germination and establishment of the
seedling is relatively great, it seemed quite legitimate to use
the weight of green tissue produced by these leaves as a measure of
the physiological capacity of seedlings of various types. The fact
that these leaves are differentiated in the seed, however, constitutes
a valid objection against their use as a sole measure of the physio-
logical capacity of the seedling. For such purposes a constant
based upon some organ developed later seemed desirable.

In a second study,3 therefore, the tissue weight determinations
were extended to the trifoliate leaves of the third node, as well as
to the primordial leaves of the second node. This leaf was used
because groups of plants of more uniform development can be
selected at the time of maturity of this leaf, than at any later
stage, and because the first compound leaf reaches a degree of
maturity sufficient for the purpose of the present study before the
primordial leaves are too old to be used. It is possible, therefore,
to check results by determinations made on organs differentiated
both in age and in structure. In the first investigation the green
weight of the leaf tissue served as the fundamental measurement.
In addition to this character certain measurements on the sap
properties were also made. In the study of the saps some diffi-
culties were encountered, and it seemed desirable to discontinue
that phase of the work temporarily and to carry out determinations
of dry weight and water content instead. The present study,
therefore, has to do only with the green weight, the dry weight, and
the percentage of dry matter.

Recent investigations fell into two phases. The first was an
endeavor to determine to what extent seedlings which are morpho-
logically aberrant in the race to which they belong also differ from
the normal seedling of the race in their physiological characters,
in so far as these can be measured by the capacity for the production
of tissue. In the second the investigation was extended from intra-
racial to inter-racial comparisons, to ascertain if possible to what

3 Harris, J. ARTHUR, Further studies on the interrelationship of morphological
and physiological characters in seedlings of Phaseolus. Brooklyn Bot. Gard. Mem.
1:167-174. IQI

1921] HARRIS—PHASEOLUS 153

extent a highly abnormal race differs from the parental strain
from which it originated.

Materials and methods

In this paper the characteristics of a fully heritable teratological
race are considered. The material was furnished by a tetracotyle-
donous race, the origin and general characteristics of which have
been considered elsewhere. The tissue of plants of the tetra-
cotyledonous race were compared with those of the normal line
from which it originated.

Seeds of the two series grown in the same field in 1917 were
germinated in flats of sand in 1919. Four lots of fifty seeds each,
two of the tetracotyledonous plants and two of the normal ances-
tral line, were germinated in alternate positions in the same flat.
Conditions, therefore, were as nearly comparable as possible in the
germination of the two series. When the seedlings were of the
proper size for potting, one seedling of the tetracotyledonous race
and one normal control taken from the same flat were transferred
to 3-inch pots of soil, where they stood until they were ready for the
collection of samples of tissues. Weighings were then made of the
primordial leaves in the two cases. Thus, although weight and
other characteristics vary from sample to sample because of age
and the innumerable slight influences of significance in growth,
the aberrant plants and their controls from the very beginning had
as nearly as possible identical environment. However much the
pairs combined in the same sample may differ among themselves,
there seems no possibility of considering that the differentiation
here shown to exist between the morphologically typical and the
morphologically aberrant individuals is due to any extrinsic cause.
In the absence of any knowledge of the amount of variation in the
characteristics of the leaves to be investigated, it was impossible
to compute in advance the size of the sample which should be taken.
Accordingly it was arbitrarily fixed as 100 plants.’

4 Harris, J. Artour, A tetracotyledonous race of Phaseolus vulgaris. Mem.
N.Y. Bot. Gard 6: 229-244. 1916.

, De Vriesian seatetion in the garden bean Phaseolus vulgaris. Nat.
Acad. Sci. 2:317-318. 1916.

5 Sample 305 contained 96 plants, sample 252 only 81 plants, and sample 259

contained 138 plants.

154 BOTANICAL GAZETTE [SEPTEMBER

In work with the variants in normal lines of beans there is no
difficulty whatever in distinguishing primordial leaves from those
subsequently formed, except occasionally in extreme variations
involving stem characters such as would ordinarily be classed as
fasciations. In the case of the tetracotyledonous race, however, it
is often difficult to distinguish between true primordials (those |
formed in the seed) and the simple leaves (not compound) formed
subsequently. This difficulty was noted in the first paper on the
tetracotyledonous race, and two series of countings at different
stages of development of the seedling were made to determine to
what extent personal equation may affect the constants for number
of primordial leaves.

For practical reasons it was not feasible to count the leaves of the
tetracotyledonous plants used in these experiments immediately
after germination. Countings, therefore, were made just before
the samples were taken. The numbers recorded are those of leaves
which were regarded as certainly primordial. Those which from
their color or texture appeared to be of subsequent development
were omitted. In this race filaments are of rather frequent occur-
rence. These are probably morphologically much reduced leaves,
and were also disregarded. Thus the number of primordial leaves
is probably on the average slightly under rather than over the true
number for the series as a whole. Since we are primarily concerned
with a comparison between definite types of seedling classification
with respect to number of leaves,. this procedure can introduce no
sensible error into the results.

Because of some uncertainty as to the leaves which were to
be considered primordial and the considerable variation in the
stages of development of the compound leaves in the tetracotyle-
donous plants, it did not seem feasible in the majority of determina-
tions to consider separately the weight of tissue formed by the
compound leaves. This, however, has been done indirectly in the
case of certain samples based on the plants as a whole.

Data
The data fall in three groups: a series of weighings of primordial
leaves of plants unclassified with respect to number of primordial
leaves; a series of weighings of primordial leaves of plants classified

1921] HARRIS—PHASEOLUS

T55

with respect to number of primordial leaves; and a series of weigh-
ings of total epicotyledonary tissue.

TABLE I
MEAN GREEN WEIGHT PER PLANT AND PER LEAF IN SEEDLINGS OF A TETRACOTYLE-
DONOUS RACE AND IN NORMAL PLANTS OF THE ANCESTRAL RACE

VALUES PER PLANT VALUES PER LEAF
SAMPLE
Abnormal | Control | Difference Pores Abnormal] Control | Difference oa
Unclassified
A200. os 0.6991 | 0.7516 |—0.0525| — 6.9 |0.1718 |0.3758 |—0. 2040] —54.2
Re 0.6972 | 0.7607 |—0.0635| — 8.3 |0.1680 Jo. 3804 |—0. 2124) —55.8
$O8 ce 0.6323 | 0.7568 |—0.1245| —16.4 |0.1542 |0.3784 |—0.2242| —59.2
Ps ss ana 0.7012 | 0.6862 |+0.0150] + 2.1 [0.1703 |o.3431 |—0.1638) —47.7
2 leaves
BEG. 6. 0.4520 | 0.7263 |—0.2743| —37.7 |0.2260 |o.3632 |—0.1372| —37.7
SOR cc 0.5958 | 0.7994 |—0. 2036 25.4 10.2979 10.3997 |—0.1018] —25.4
3 leaves
4 Gane 0.6313 | 0.7760 |—0.1447| —18.6 |0.2104 |o.3880 |—0.1776| —45.7
Cs Ee 0.5662 | 0.7189 |+0.1527| —21.2 |0.1887 |0.3595 0.1708] —47.5
BBB easy sy 0.5791 | 0.7766 |—0.1975| —25.4 |0.1930 |o.3883 |—90.1953| —50.2
SE ee 0.6577 | 0.8015 |—0.1438] —17.9 |0.2192 }o.4008 |—0.1816| —45.3
319......] 0.6200 | 0.7817 |—0.1617]} —20.6 |0.2067 |o.3909 |—0.1842| —47.1
4 leaves
ac ng 0.6703 | 0.7786 |—0. 1083 13.9 |0.1676 jo. 3893 |—0.2217| —56.9
B04) oC . 0.5904 | 0.6671 |—0.0677 10.1 |0.1499 |0.3336 |—0.1837) —55.0
S00, 0.7066 | 0.8103 |—0.1037| —12.7 [0.1767 |o.4052 |—0. 2285) —56.3
2905) 0% 0.6556 | 0.8142 |—0.1586] —19.4 [0.1639 |0.4071 |—0.2432| —59.7
Bes co 0.7368 | 0.9028 0.1660 18.3 |0.1842 |o.4514 |—0.2672| —59.1
Ly ee 0.7201 | 0.7783 |—0.0582] — 7.4 }o.18 .3892 |—0. 20902} —53.7
2 a 0.7375 | 0.7529 |—0.0154 2.0 |0.1844 |o.3765 |—0.1921] —51.0
5 leaves
LF eo 0.6371 | 0.7639 |—0.0998 13.5 |0.1274 |0.3685 |—0.2411| —65.4
BOR yc, 0.6409 | 0.6987 0.0578] — 8.2 |0.1282 jo. 3494 |—0.2212| —63.3
ty ee ae 0.7334 | 0.7867 |—0.0533] — 6.7 {0.1467 |o.3034 |—0.2467| —62.7
GOO Oe sk 0.8032 | 0.8366 |—0.0334 3.9 |0.1606 jo.4183 |—0.2577| —61.6
AI ee, 0.7125 | 0.7987 |—0.0862 10.7 |0.1425 |0.3994 |—0.2569| —64.3
6 leaves :
Bec. 0.7123 | 0.7268 |—o0.0145| — 1.9 |0.1187 |0.3634 |—0. 244 67.3
ao a Ss 0.7351 | 0.7646 |—0.0295| — 3.8 |0.1225 |o.3823 |—0.2598| —67.9
oo eee ©.7950 | 0.8248 |—0.0298] — 3.6 |0.1325 |o.4124 |—0.2799| —67.8
7 leaves
Cy peers 0.7312 | 0.7785 |—0.0473| — 6.0 |o.1045 [0.3893 |—0. 2848) —73.1
Epicotyl
4a S., 1.4388 | 2.0369 |—0.5981] —20.4 | ------efe cree efor reer fe ere eeee
ee I.§442 | 1.9333 |—0.3691| —190.3 | .-.--- efor ere espe eee eee tde rete es
BAG cae: 1.5448 | 2.0396 |—0.4948] —24.3 |... .eeefeee eee efe eset ee cfe re eees
S80. is 1.6325 | £.9028 |—0.2703] —14.2 |. wee eee fe ese eeefe cere netfee cece
CS are 1.0634 | 1.1512 |—0.0878 Pf One FeO re eee

PLANTS UNCLASSIFIED WITH RESPECT TO NUMBER OF PRIMORDIAL
LEAVES.—In preliminary work (samples 226-229) the total weight
of primordial leaf tissue in the abnormal seedlings is compared

156 BOTANICAL GAZETTE [SEPTEMBER

with the total weight in the control plants irrespective of the
number of primordial leaves formed by the individual plants of the
tetracotyledonous race. The total number of leaves per plant,
however, was determined in these four series.© Thus it is possible
to give the average weights both per plant and per leaf in the two
series. The results show that in three of the four cases the green
weight as given in table I of the approximately four primordial
leaves of the tetracotyledonous race is lower than that of the two
_ primordial leaves of the dicotyledonous strain. The percentage
differences in total weight range from +2.1 to —16.4, with a
general average of —7.37. When the comparison is made on the
basis of mean weight per leaf, the primordial leaf of the abnormal
seedling is found to be on the average 54.22 per cent lighter than
the leaf of the normal seedling.

For dry weight, given in table II, all four series show lower
average weight in the tetracotyledonous strain. The percentage
differences for dry weight of primordial leaves per plant vary from
—1.6 to —18.0, with a general average of —10.90. On the basis
of mean dry weight per leaf, the weight for tetracotyledonous plants
is found to be from 49.6 to 59.9 per cent lower than that of the
normal seedling, with a general average percentage difference
of —55.92. Thus the results for these four samples clearly indicate
that an abnormal race shows the same relationship to the normal
parental race as do abnormal individual seedlings to the normal
seedlings in the same race.

PLANTS CLASSIFIED WITH RESPECT TO NUMBER OF PRIMORDIAL
LEAVES.—Upon the completion of this preliminary comparison it
seemed worth while to analyze the relationships more minutely
by considering individually the results for seedlings of the tetra-
cotyledonous race with varying numbers of primordial leaves.
These results were only attained at the cost of great labor, since
it was difficult to secure considerable numbers of seedlings of any
given type simultaneously. It was necessary, therefore, to make
determinations for abnormal and control plants in small sub-
samples, and to combine these to form samples of 100 seedlings

6 The average numbers per plant were as follows in the four samples: 226=4.07,
227=4.15, 228=4.10, and 229=3.91.

1921] HARRIS—PHASEOLUS 157

each. The results are shown in table I for green weight, table II
for dry weight, and in table III for the percentage of dry matter in
the primordial leaves. The data show that in the case of both
green and dry weight tissue production is invariably higher in the

TABLE II

MEAN DRY WEIGHT PER PLANT AND PER LEAF IN SEEDLINGS OF A TETRACOTYLEDONOUS
CE AND IN NORMAL PLANTS OF THE ANCESTRAL RACE

VALUES PER PLANT VALUES PER LEAF
SAMPLE ;
Abnormal} Control | Difference amend Abnormal Control Difference oo
Unclassified
Cs ae ere 0529 | 0.0600 |—0.0071] —11.8 |0.0130 |o.0300 |—o0.0170) —56.6
oe eg ee 0.0530 | 0.0604 |—0.007 12.2 |0.0128 |o.0302 |—o.o01r74| —57.6
2808 0.0528 | o. —o0.0116] —18.0 |0.0129 Jo.0322 |—0.0193} —590.9
re Ts en 0.0539 | 0.0548 |— — 1.6 10.0138 |0.0274 |—0.0136| —49.6
2 leaves
71 ete ee 0.0355 | 0.0587 |—0.0232| —39.5 |0.0178 |o.0294 |—0.0116] —39.4°
O50 foas 0.0403 | 0.0542 |—0.0139| —25.6 |0.0202 |o.0271 0.0069] —25.4
3 leaves
OA AE 0.0492 | 0.0649 |—0.0157| —24.1 |0.0164 |o.0325 |—0.0161] —49.5
79 Ens 0.0427 | 0.0562 |—0.0135| —24.0 |0.0142 |o.0281 |—0.0139] —49.4
se Re 0.0404 | 0.0565 |—o.0161| —28.4 {0.0135 |o.0283 |—o.0148} —52.2
BOS es 0.0404 | 0.0539 |—0.0135| —25.0 |0.0135 |0.0270 |—0.0135] —50.0
ade clog fe 0.0360 | 0.0488 |—0.0128} —26.2 [0.0120 |o.0244 |—0.0124] —50.8
4 leaves
1 Gsl graae 0.0517 | 0.0641 |—0.0124] —19.3 [0.0129 |o.0321 0.0192} —59.8
204.205). 0.0470 | 0.053 0.0062} —11.6 {0.0118 |0o.0266 |—0.0148} —55.6
2060 oe) 0.0493 | 0.0576 |—0.0083] —14.4 |0.0123 |o.0288 |—0.0165| —57.2
20000 2.) 0.0409 | 0.0540 |—0.0131| —24.2 |0.0102 |o.0270 |—0.0168) —62.2
200 Scr. .0444 | 0.0568 |—0.0124] —21.8 |o.o1II |o.0284 |—0.0173| —60.9
KO Oe 0444 | 0.0516 |—0.0072} —13.9 |0.o011r |o.0258 |—0.0147} —56.9
$20 80. 0.0434 | 0.0478 |—0.00 Q.2 |0.0109 |o.0239 |—0.0130] —54.3
5 leaves
p18, ieee 0.0488 | 0.0604 |—o0.0116] —19.2 |0.0098 |o.0302 0.0204 67.5
B08 6 0.0462 | 0.0537 |—0.0075| —13.9 |0.0092 |o.0269 |—0.0177| —65.7
roe AE 0.0501 | 0.0562 |—0.0061] —10.8 |0.0100 |o.0281 |—o.0181| —64.4
SOG ys 0.0496 | 0.0549 |—0.0053 9.6 |0.0099 Jo.0275 |—0.0176] —64.0
eg See 0.0423 | 0.0500 |—0.0077/ —15.4 |0.0085 |o.0250 |—0.0165) —66.0
6 leaves
250.2 s.. 0.0528 | 0.0558 |—0.0030] — §.3 |0.0088 |o.0279 |—0.o191| —68.4
ee 0520 | 0.0555 |—0.0035| — 6.3 |0.0087 |o.0277 |—9.0190| —68.5
Ce eee 0.0496 0565 0069] —12.2 |0.0083 |o.0283 |—0.0200] —70.6
7 leaves
a59..5... 0.0557 | 0.0614 |—0.0057| — 9.2 |0.0080 |0.0307 |—9.0227| —73.9
Epicotyl
cP. eae O:1048 | 0.1507 [0.0450]... 2. oe | ects ee epee ee tbe see tteerete es
M40 caus O.4580 10.3443 (0. C204 5 pe ee ee ee ee Eee eee eee
ae a ne O.1027 | O, F554 (0.0587). oP finns ee afl so ew py wees ss
250.500, OAs 16. Yare 1-8 00901 eo a is eer ee ce ds eee
ot Canes G.0030 | GO 1045" 10.0100) 6c. oe he ce bea vk es cients tes

158 BOTANICAL GAZETTE [SEPTEMBER

two primordial leaves of the normal ancestral strain than it isin the
two to seven leaves of the tetracotyledonous strain. The percentage

TABLE III
dsppaioe age SUBSTANCE IN SEEDLINGS OF A TETRACOTYLE-
RACE AND IN NORMAL PLANTS OF THE
ANCESTRAL RACE

PRIMORDIAL LEAVES
SAMPLE :
Abnormal Control Difference
Unclasifed
Dee ee Pa 7.566 7.982 —o.416
“ei Oyen Ge eas 7.601 7.940 —0O.339
=F Rte ale ESOL Na as 8.350 8.509 —0.150
990s. ee ee, 7.686 7.986 —0.3
2 leaves
BRB. Gag ie eae 7.853 8.082 —0. 229
BOG a a 6.765 6.788 0.023
3 leaves
OSS ere ee 7.710% 8.363 —0.570
Oy I OES 7.541 7.817 —o.276
5, eas gene Sara 6.976 7.2968 —0. 299
BOSC Nbc cows cade 6.142 6.724 —0o.582
BIG. vies oe 5.806 6.242 —0.436
4 leaves
Bee Ors ike oc 7712 8.232 —0.520
BOA ee ee 7.841 7.974 —0.133
ABO er eels 6.977 7.108 —0.131
S00. i oe ees 6.238 6.632 —0.394
MO ct ane 6.026 6.291 —o.265
Std ee 6.165 6.629 —0o.464
SIG eee, 5.884 6.348 —0o.464
5 leaves
S546; . eee a, 7.659 8.106 —0.537
208s a Se ee es 7.208 7.685 —O.477
S07 a ee 6.831 7.143 —0.312
SOO. Ss ee. 6.175 6.562 —0. 387
Sal oe. 5.936 6.260 —0.324
6 leaves
SEO ee cea vee 7.412 677 —0. 265
B0Qc Se 7073 7.258 —0,185
GOP aa Pe de 6.238 6.850 —0o.612
7 leaves
SEQ Ub aa) Ve 7..620 7.892 —0.272
Epicotyl
SAA ie eee. 7.283 7.398 “OL LTS
BAG. oes tk 7.505 7. Sar —0,036
BAB ee Cree: 7.205 7.423 —o,128
B50 5 i eee ees 7.2 7.425 —0.118
pe ye Spa eo eas e 8.834 9.083 “0.249

values show considerable variation from sample to sample. As
might have been expected on a priori grounds, the deficiency of

1921] HARRIS—PHASEOLUS 159

the weight of primordial leaves in the tetracotyledonous line is
greatest when only two leaves are formed.

A comparison of the average percentage differences for abnormal
plants with various numbers of leaves gives the following results:

No. of leaves Green weight Dry weight
Bet re aa sche ls — 31.55 — 32.55
Bere ea i ees — 20.74 — 25.54
Aes aa Skewes —1I1.97 —16.34
Sra ewe eis 8,60 —13.78
Gee era ae ak m2 16 — 7.93

Only one sample is available for seedlings with seven primordial
leaves, and it is omitted from the comparison. The results for the
other five classes show that:

a) The difference between the ve weight of primordial leaf
tissue in the abnormal seedling and its normal control decreases as
the number of leaves in the abnormal plant increases, but that
throughout the entire range of variation of leaf number studied the
tetracotyledonous plant produces a smaller total weight of leaf
tissue than do normal plants of the line from which it was derived.

b) The differences between tetracotyledonous and dicotyle-
donous plants are always greater when the comparison is made on
the basis of dry weight than when it is made on the basis of green
weight.

If the comparison be made.on the basis of average weight per
leaf the following results are obtained:

No. of leaves Green weight Dry weight
eee rer nena —31.55 —32.40

Cae Ea Sirians —47.16 —50.38

re he eg eer — 55.95 —58.12

Lae ae ce NS 7 —63.46 —65.52
Oe ay cee cs — 67.66 —69.16

The percentage differences in average weight per leaf of course
increase as the number of leaves in the abnormal seedlings increases.
Again the greater percentage difference when dry weight serves as a
basis of comparison is conspicuous. The percentage of dry matter

160 BOTANICAL GAZETTE [SEPTEMBER

in the seedlings of this extremely abnormal race is shown in com-
parison with the normal control plants in table III. The results
are self-explanatory. Without exception, in the twenty-three
samples representing weighings of 9958 leaves of abnormal and
4668 leaves of normal plants, the percentage of dry matter is lower
in the abnormal than in the control series. A study of the averages
for the individual groups of seedlings, classified with respect to
primordial leaf number, does not suggest a significant difference in
the percentage of dry matter in the different classes of seedlings.
Probably a far larger series of weighings would be required to
bring out such a differentiation if it exists at all.

TOTAL WEIGHT OF EPICOTYLEDONARY TISSUE IN FLANTS OF
TERATOLOGICAL AND NORMAL RACES.—In the foregoing discussion
comparisons were limited to the weight of primordial leaves. This
was done because of the difficulty of securing leaves subsequently
formed in comparable stages of development in the normal and
teratological seedlings. It seemed desirable to supplement these
studies by the determination of the total weight of tissue produced
by the two races. The results for a comparison of the total weight
of tissue produced above the cotyledonary node by tetracotyle-
donous plants and their normal control of line 139, are shown under
the heading ‘‘epicotyl”’ in the fundamental tables of data.

The constants show that without exception the green weight and
dry weight per plant and percentage dry matter are higher in the
normal than in the tetracotyledonous plants. The percentage
differences range from —7.6 to —29.4 in the case of green weight,
and from —10.1 to —30.5 in the case of dry weight. The differ-
ences in percentage of dry matter range from —0.036 to —0.249.
The average weight of green tissue per plant is 1.4447 for the
abnormal and 1 .8088 for the control series, or a difference of —o . 3640
gm. The average.dry weight per plant is 0.1093 for the abnormal
and o.1384 for the normal seedling, or a difference of —o.0291 gm.
The average percentage difference for the green weight is — 18.96,
while for dry weight the difference is —20.30. The percentage of
dry material in the abnormal seedling is 7.6448 as compared with
7.7740 in the control, a difference of —o.1292.

1921] HARRIS—PHASEOLUS 161,

Summary

This paper presents the results of an investigation of green
weight, dry weight, and of the ratio of green weight to dry weight in
primordial leaf tissue in mutant and parental races of Phaseolus
vulgaris. The data show that when grown under as nearly identical
conditions as possible the primordial leaves of the mutant (tetra-
cotyledonous) show a smaller green weight, a smaller dry weight,
and a lower ratio of dry weight to green weight than those of the
normal (dicotyledonous) parental race. Thus the tetracotyle-
donous race is distinguished not merely by striking morphological
differences, but by physiological differentiation as well. In this
respect the results for the heritable mutant race are in agreement
with those for variant individuals within the same strain.

STATION FOR EXPERIMENTAL EVOLUTION
Cop Sprinc Harsor,

TECHNIQUE IN CONTRASTING MUCORS
ALBERT F. BLAKESLEE, DoNALD S. WELCH, AND J. LINCOLN CARTLEDGE
(WITH TWO FIGURES)

For the last two years a more or less intensive study of the
sexual reactions between different races of mucors has been con-
ducted. These reactions have been tested by growing the races
side by side in culture dishes under suitable environmental condi-
tions and observing the abundance of conjugations which take
place between the races thus “contrasted.’”’ In making so large
a number of contrasts, it has been necessary to develop a special
technique in order to minimize the time consumed in the prepara-
tion and handling of the cultures, to obtain greater accuracy in
making observations, and to avoid the various experimental
errors to which one untrained in the work is liable. As has
already been shown, the discordant results obtained by different
investigators working with the same species of mucors may be
explained by a difference in the technique employed. It has
seemed desirable, therefore, to give in some detail the methods used
before presenting the results of the investigations in a series of
papers which it is hoped to publish shortly.

GROSS CULTURES.—As a source of races to be investigated,
gross cultures grown in the laboratory are more convenient than
natural cultures found out of doors. Certain forms are character-
istic of certain types of substrata. Most mycologists are familiar
with the flora obtained from dung cultures made by placing bits
of dung on filter paper above damp peat moss in a covered crystalliz-
ing dish. Brazil nuts have been found a constant source of certain
forms such as Cunninghamella bertholletiae, C. echinulata, Syncephal-
astrum, and certain other species. In making gross cultures of
these nuts it was found convenient to use chiefly the shells, since
the meats furnish too luxuriant a supply of nutrient, so that
Rhizopus is likely to overgrow the less vigorous forms in the culture.
The nuts were cracked separately and their shells placed in piles

Botanical Gazette, vol. 72] [162

1921] BLAKESLEE, WELCH, & CARTLEDGE—MUCORS 163

on filter paper above peat moss in shallow galvanized cake tins
covered with glass plates. The shells of each nut were kept
separate and placed near the edge of the culture dish in order to
facilitate their examination with the hand lens. The hands and
the nut-cracker were sterilized with alcohol after cracking each nut,
in order to prevent an undue amount of infection of one nut from
spores which may have been on the one cracked previously. It
was the usual practice to reserve a culture dish for the nuts obtained
from a single collection, despite the fact that many of these collec-
tions were from stores within a radius of thirty-five miles from
New York City, and very probably had the same ultimate source.

Another prolific origin of mucors is soil obtained from different
sources. It was most conveniently scattered on bread, which fur-
nished a suitable medium for the germination and growth of the
spores which the soil might happen to contain. The bread before
using was sterilized in the autoclave without pressure for about 5
minutes, a longer time not being used since it might make the bread
soggy. If the surface of the bread has become dry, it may be
moistened slightly with sterilized water.

STOCK CULTURES.—The races were obtained in pure cultures
by making transfers from individual heads in the gross cultures.
Since there is possibility of spores from another race being on the
head from which the transfer was made, a second pure transfer
was regularly made from an individual head in the first test tube,
thus avoiding the likelihood of the stock cultures being mixtures of
more than a single strain. As a precaution against too rapid dry-
ing out, the amount of agar flour in the stock cultures was raised
from 2 to 3 per cent, and standard no. 230 nutrient, consisting of 2
per cent each of dextrose and dry malt extract plus o.1 per cent
meat peptone, was used.

Inrection.—Knowledge of an investigator’s methods may
enable the impartial critic to judge whether the known sources of
experimental error are properly guarded against. To the bacteri-
ologist and the student of fungi in pure cultures, one of the greatest
sources of error is infection. When this infection is caused by a
form different in appearance from the species under cultivation,
the presence of the foreign cadclesl: is readily recognized. Infection

164 BOTANICAL GAZETTE [SEPTEMBER

is less readily recognized, however, when the invading growth is
another race of the same species. Syncephalastrum and Cunning-
hamella are forms which bear their spores externally and shake them
off at the slightest touch or breath of air. When a dish containing
a mature culture of these species is opened, the spores may be seen
to rise in clouds. The spores of Rhizopus, although inclosed in a
sporangium, are readily scattered into the air by the rupture of
the brittle sporanguim wall, and in consequence Rhizopus also is
a common source of infection. That the air may be filled with
viable spores of both sexes of Cunninghamella has been shown by
exposing Petri dish cultures for a short time and growing them
at a temperature suitable for zygospore formation. In the
laboratory where Cunninghamella had been recently grown, it was
always possible to find growths of the same species in Petri dishes

exposed in this way, and frequently both the sexual races were
obtained, as shown by the production of their zygospores. . Experi- _
ence has shown, therefore, that in working with Cunninghamella one
must observe greater precautions to avoid air-borne infection with
other strains of the same species than is necessary when working
with many other forms.

Not only are cultures of Cunninghamella especially liable to
infection with spores of the same species, but the spores of this
species which gain access to a mature culture are able to germinate
and grow on the aerial mycelium which they infect. With most
mucor species, vigorous growth on the nutrient substratum is
necessary before zygospore formation is possible. With Cunning-
hamella, however, connection with the nutrient agar does not appear
to be necessary in order to allow the mycelia to assist in zygospore
formation, since if spores of one sex are planted on an aerial growth
of the other sex, zygospores are likely to be produced. This
peculiarity of Cunninghamella was responsible in the earlier cultures
for the appearance of zygospores where they should not be found
on the theory of sexual dimorphism, and led to a repetition of the
first series of cultures and a revision of the technique.

NUTRIENT MEDIA.—The method of growing and testing races
of Cunninghamella for sexual reactions was the same as that adopted
for other forms, with such slight modifications as the peculiarities of

1921] BLAKESLEE, WELCH, & CARTLEDGE—MUCORS 165

the individual species demanded. Two per cent agar with the addi-
tion of different nutrients was used as a substratum in all cases.
_ The. formula varied with the different species tested. No. 230
standard stock nutrient (already described) was used in the tests
when possible. Before starting an extensive series of tests of a
given species, however, the effects of a number of different nutrients
were tested, and the one chosen which was able to support a relatively
abundant production of zygospores. For ‘‘imperfect hybridiza-
tion’’ reactions no better nutrient was found than no. 362, which
is a milk whey agar consisting of 2 per cent agar, 1 per cent dextrose,
and 2 per cent dry milk whey powder. Some species form zygo-
spores at laboratory temperatures, while others require a higher
temperature for sexual reproduction. The species of Cunning-
hamella investigated belong to the latter class, and accordingly
tests of this genus have been grown in the incubating oven at
temperatures between 24° C. and 28° C.

CULTURE DISHES.—A suitable culture dish is a matter of some
importance, especially when large numbers of cultures are handled
together. It should be relatively small in order to economize
space, and yet should provide sufficient surface of the nutrient
medium to support vigorous growth of the two contrasted mycelia.
The danger of infection must be reduced to a minimum, and yet
the dishes should be such as to be manipulated easily in being
filled with nutrient, inoculated with the races to be tested, stored
during incubation, and examined under the microscope. Test
tubes, although fitted for holding material in stock cultures,
require considerable time to be plugged, filled, and sterilized, and
moreover cannot easily be handled for observation under the
microscope. Petri dishes, while in many ways superior to test
tubes, are expensive, do not stack well, and are furnished with a
loosely fitting rimmed cover. The Syracuse watch glass with
ground rim for pencil labeling has been found to satisfy all the
requirements of a safe and convenient culture dish, and has been
used almost exclusively in recent years in testing contrasts between
different races. They are conveniently handled in stacks of five,
four dishes for cultures and an empty one for the top cover. Each
dish, except the bottom one, serves thus as a cover for the one

166 BOTANICAL GAZETTE |SEPTEMBER

below. A single stack, therefore, can be used in testing each
of two races by contrasts with a plus and a minus tester. The
stacks of culture dishes are dry sterilized, and when cool filled with
sterilized nutrient agar slightly above the melting point. If the
agar is too warm, moisture may condense on the covers and later
drop on to the surface of the hardened agar. The process of pour-
ing agar into the dishes is carried on in a special culture room to
minimize danger of contamination. The cultures are ready for
inoculation as soon as the agar has begun to harden. Pouring
agar into sterile dishes rather than sterilizing the dishes after they
have been filled not only saves considerable time in the process,
but avoids the spattering of nutrient on the edges of the dishes,
which is likely to ensue when they are autoclaved, and is a ready
source of infection. It has not been found necessary to use cleared
agar, but the sediment at the bottom of the flask from which the
stacks are poured has usually been discarded. This sediment may
be conveniently anchored to the bottom by cooling the flask when
full in a shallow pan of water.

InocuLaTions.—Since forty or more individual races in test
tubes may be used in inoculating a given series, it is obvious that
some precautions are necessary to avoid contamination from spores
falling from these tubes, or from the weft of spore material taken
from them for inoculation. Exposed Petri cultures have shown
that this danger is great if not guarded against. In making inocula-
tions, great care was taken never to expose to the air in the inoculat-
ing chamber any spore material in a dry condition. A fairly
large piece of rather soft agar was transferred with a flamed plati-
num needle or spatula to the tube from which it was wished to
obtain a transfer. The piece of agar was cautiously pushed against
the spore material, and thoroughly mixed with it, care being
observed that no dry filaments adhered to the needle or to the
mixture of agar and spore material to be used as the inoculum.
Moreover, the cotton plug was not removed suddenly from the
test tube, since if this is done spores are likely to be shaken into
the air, sometimes in visible clouds. After the inoculation the
needle was not at once flamed, as the heated inoculum may sputter
and scatter bits containing viable spores. The needle, therefore,
was left in a tube of about 80 per cent alcohol while the label was

1921] BLAKESLEE, WELCH, & CARTLEDGE—MUCORS 167

being written on the culture. This alcohol bath helps to sterilize
not only the needle but also the base of the needle holder, which
cannot readily be flamed, but which may carry spores from the
test tube cultures. The alcohol was burned off and the needle
flamed before a new inoculation was made. A layer of shot will
be found convenient to weight the jar of alcohol and to receive
the point of the needle. It is a rule of the laboratory never to lay
a test tube down from which a transfer is being made until the
label is written on the new culture.

The first race to be tested was inoculated in a streak at the
left and at the right respectively of the first and second culture
dishes in the stack. Similarly the second race was streaked at
the left of the third dish and at the right of the fourth dish. In
like manner other stacks were inoculated with the remaining races to
be tested, so that finally a series of stacks was secured with two
of the dishes streaked with one race and two dishes with another
race. They were then ready to be planted with the testers, which
are most conveniently a pair of races of opposite sex. In such a
case, the plus was streaked on the right of the first and third culture
dishes of each stack, and the minus on the left of the second and
fourth dishes. Each dish, therefore, contained a tester and a
race to be tested, and each stack accordingly completely tested
two races. An advantage in choosing a plus and a minus race as
the two testers in a series was that they could be planted together
as controls for the production of zygospores. They may be
grown in duplicate, and a pair of dishes with nutrient but without
inoculations may complete the control stack and give evidence
of the amount of infection to which the cultures are liable. In
inoculating the testers a larger amount of spore material was rolled
up on the needle, which sufficed without renewal for the inocula-
tion of 30 or 4o dishes. With practice the process of inoculation
could be carried on with relative rapidity. In inoculating a culture
with more than a single race, the needle should be kept on its own
side, to decrease the likelihood of spores falling upon a part of the
substratum reserved for another race.

When “imperfect hybridization” was expected, the tester and
the race to be tested were streaked so that the lines of inoculation
formed a V instead of running parallel. In consequence, the two

168 BOTANICAL GAZETTE |S EPTEMBER

mycelia met sooner in their growth at one end of the line of contact
than at the other, and thus offered a greater area at a given time
for the observation of sexual reactions which may soon be covered
by the later growth of the mycelium. Obviously the angle of the
V must be left open, and care taken in planting a tester to avoid
touching with the needle the previous. line of inoculation. The
distance between the points or lines of inoculations may be a matter
of some importance, since certain forms fail to produce zygospores
in the line near the inoculations, while others produce them only
within a distance of a few millimeters from the inoculations.

After inoculation, the stacks are stored in the incubating oven
if greater than laboratory temperature is necessary. If the stacks
are inverted until the mycelium covers the agar, the danger is
avoided of water condensing on the dishes above and falling upon
the cultures, with a consequent running together of the recently
made inoculations. It may be found desirable to have jars of
water on the culture shelves to prevent the nutrient from drying
out before they are finally recorded. Before the cultures had
matured, they were inspected to see whether any inoculation had
failed to grow. With Cunninghamella the inspection was more
thorough than with most other forms, and consisted in an exami-
nation for beginnings of conjugation such as are seen in “imperfect
hybridization.”” Apart from this early inspection on the first or
second day after inoculation, and before there is much danger in
disseminating spores from the cultures into the air, the stacks were
not opened before being sterilized in the autoclave, generally on the
seventh or eighthday. The heat of the autoclave melts the agar and
tends to glue the filaments to the bottom of the dish above. It
_ was found convenient, therefore, to have the stacks inverted during
sterilization, with a pan below to catch the melted agar. Just
before cooling the stacks were erected and each dish lifted in succes-
sion. Any of the cultures still adhering to their covers after this .
procedure may be freed by the use of alcohol. Keeping the dishes
closed while the spores are likely to be shed reduces the amount of
infection of the laboratory air, which is probably impossible to
prevent entirely when a species like Cunninghamella or Syncephalas-
trum is cultivated in a wholesale manner. Fig. 1 shows a series

1921] BLAKESLEE, WELCH, & CARTLEDGE—MUCORS 169

of empty stacks in the inoculating room ready for pouring. A
tube of alcohol is seen at the right holding the inoculating needles.

EXAMINATION OF CULTURES.—The cultures were examined under
the binocular microscope by the transmitted light of a substage
electric lamp. In some species the mycelium and spores above the
substratum hid any zygospores which might be present, and neces-
sitated manipulating the culture before examination. Wetting
with alcohol, pressing down the aerial growth with the finger, and
even washing the spores away under a jet of water occasionally

Fic. 1.—Inoculating chamber with stacks of culture dishes ready for pouring

was found necessary. The relative abundance of zygospores when
present is shown by the grades A to D. A indicates about the
maximum number of zygospores to be expected of the species under
the given environmental conditions, while D indicates generally less
than a dozen zygospores in the whole culture. Absence of zygo-
spores is indicated by O. Naturally the zygospores would be
expected to form in greatest numbers at the line of €ontact between
the opposing mycelia, and in some species produce a sharply defined
dark line. In forms like Rhizopus and Cunninghamella, in which
the zygospores are produced on branching aerial filaments, the
zygospores may spread from this median line until ultimately

170 BOTANICAL GAZETTE [SEPTEMBER

they are scattered through the whole culture. They should not
be least abundant in the center, however, and a very few isolated
zygospores at some distance from the line of contact make one
suspicious of possible infection and demand a repetition of the
culture.

In the study of incompleted sexual reactions such as are found
in ‘‘imperfect hybridization,” greater care must be exercised than in
the observation of zygospores, since the cultures have not been
sterilized, and infection may take place in an early examination of
the dishes and be the cause of the sexual reactions seen when the
cultures are looked at later. At first glass plates were used to
cover the cultures, to prevent the delicate filaments from drying
and collapsing while they were being examined. This entailed
cleaning and sterilizing the plates in alcohol and afterwards drying
them, and consumed more time than the procedure finally adopted.
By this method a-stack was placed on a sheet of wet blotting paper
and covered with a crystallizing dish lined with moist paper,’ thus
forming a humidor for the cultures. The stage of the binocular
microscope was covered by several layers of wet blotting paper
perforated to match the opening in the stage for the entrance of
light. A collar of moistened blotting paper formed a moist chamber
with the wet paper on the stage and allowed the examination of
a culture to continue fér some time without collapse of the hyphae.
The cover was removed from the stack in the humidor formed by
the crystallizing dish and placed upside down on the table. The
bottom of the first culture dish was swabbed with a pledget ‘of
cotton soaked with alcohol before being put in the moist chamber
formed on the stage of the binocular, and after being examined was
placed upside down on the inverted cover. The second,. third,
and fourth cultures were treated in a similar manner, except that
the bottom of the fourth culture, which had not been in contact
with any culture below it, was not treated with alcohol. After
the last dish had been removed from the humidor and examined,
it formed the last member of an inverted stack, and a new stack
was placed in the humidor ready for examination. From time. to
time it was found necessary to re-wet or renew the blotting paper
on the binocular. The paper on the stage is theoretically capable

1921] BLAKESLEE, WELCH, & CARTLEDGE—MUCORS I7z

of transmitting spores to the cultures examined, but when the
dishes were treated with alcohol in the manner indicated, it has not
proved asourceoferror. Fig. 2 shows the arrangement of apparatus
in an examination of cultures. At the left are two trays with stacks
of cultures ready for examination. Next toward the right is a
glass plate containing the humidor and the inverted members of
a stack already examined. On the stage of the binocular is a
culture under examination. The fifth dish of the stack not yet
examined is covered by the humidor. At the extreme right is a
series of inverted stacks which have already been examined. The

Fic. 2.—Culture dishes and apparatus used

stender dish marked ‘‘alcohol” contains a wad of cotton for swab-
bing the dishes. Blotters are seen on the stage of the binocular as
well as the paper collar which partially incloses the culture under
examination.

In earlier work on “imperfect hybridization”’ the bits of mycelium
at the line of contact between two races were removed with needles
and teased out for examination under the compound microscope
in order to determine the presence or absence of sexual reactions.
Unless stages in conjugation are relatively abundant, they are much
more likely to be missed by this method than when examined at
the proper time in the living condition under the binocular. The
time of examination, however, must be well chosen, since if an
examination is attempted after the line of contact between the two

172 BOTANICAL GAZETTE [SEPTEMBER

races has become grown over, even a relatively strong reaction
may not be evident. The growth of only a few hours may render
a regrading of a culture impossible.

In the foregoing pages some of the sources of experimental
error likely to be encountered in studying the sexual reactions
between races of mucors have been pointed out, and the technique
which a familiarity with these sources has led the writers to adopt
has been outlined. What has been written may serve as an introduc-
tion to a paper to follow in this journal, in which it may be possible
to show that the discordant conclusions reached by certain inves-
tigators working with the same material may have been due to
differences in the methods employed.

STATION FOR EXPERIMENTAL EVOLUTION
CoLtp Sprinc HarBor,

GERMINATION OF AECIOSPORES, UREDINIOSPORES,
AND TELIOSPORES OF PUCCINIA CORONATA?
G. R. HOERNER

During comparatively recent years several workers have con-
tributed considerable information concerning the phenomena of
spore germination of crown rust of oats. The data herein recorded
were the result of a series of experiments undertaken to determine:
(1) the viability of aeciospores collected in several localities on
species of Rhamnus; (2) the length of time urediniospores from a
number of grass hosts, obtained in different localities, would remain
viable; (3) the conditions under which urediniospores developed
from artificial inoculations of oats in the greenhouse could retain
their ability to germinate; (4) the optimum temperature for the
germination of viable urediniospores; (5) whether teliospores devel-
oped on oat seedlings in the greenhouse would germinate imme-
diately; and (6) how early in the spring teliospores produced in the
field on a variety of hosts and collected in various places would
germinate.

AECIOSPORE GERMINATION.2—From June 22 to July 11 inclu-
sive specimens of rusted Rhamnus were collected at Montevideo
and Moorehead, Minnesota; Wahpeton, North Dakota; Aberdeen
and Brookings, South Dakota; and Beaver Dam, Wisconsin.
Immediately following collection in the field, the fresh material was
posted to Saint Paul, Minnesota, where the specimens were uni-
formly packeted in manila envelopes and filed in tin herbarium
case boxes. The minimum period from the date of collection to
the time the spore germination tests were made was 167 days.
Negative results were attendant upon all attempts at germination
of the aeciospores from any of the specimens.

‘Investigations carried on while a graduate student at the University of
Minnesota, 1916-1918.

? All spore Dee tests in these experiments, unless otherwise stated, were
made in hanging drops of distilled water in van Tieghem cells at room temperature
(about 18°C.)

173] ‘ {Botanical Gazette, vol. 72

174 BOTANICAL GAZETTE [SEPTEM BER

UREDINIOSPORE GERMINATION.—Rusted specimens of either
Avena fatua, A. sativa, or A. sterilis were collected from May 7 to
December 15 inclusive at San Diego and Santa Barbara, California;
Carrol, Missouri Valley, Onawa, and Sioux City, Iowa; Lexington,
Kentucky; Gilliam and Shreveport, Louisiana; Albert Lea, Belle
Plaine, Caledonia, Granite Falls, Hinckley, Pipestone, Preston,
Saint Paul, Sauk Center, Spring Valley, Two Harbors, Virginia,
Wabasha, and Zumbrota, Minnesota; Sedalia and Springfield,
Missouri; Pembina, North Dakota; Brookings, Bushnell, and
Newell, South Dakota; Jackson, Knoxville, and Nashville, Ten-
nessee; Beaumont and San Antonio, Texas; Lynchburg, Virginia,
and Madison, Wisconsin. The freshly acquired material was
treated in the same manner as were the specimens of the aecio-
sporic stage. After a maximum period of 87 days from date of
collection, the urediniospores collected on A. sativa were still viable.
To determine the possibility of differences in the germinating
capacity of urediniospores secured on various hosts in different
localities, when subjected to similar environmental conditions, the
following series of greenhouse inoculations was devised:

a) Rusted specimens of A. sativa were collected at Saint Paul,
Minnesota. The spores were used as the original inoculum for
infecting Improved Ligowa Oats (Minn. 281). Spores obtained as
a result of this infection were again used as a source of inoculum
for another set of the same host. This procedure was continued
for five successive spore generations.

b) Rust collected on A. sterilis at Saint Paul, Minnesota, was
used as the original inoculum for infecting the same host as that
mentioned in the preceding case. The subsequent procedure was
the same. :

c) The original inoculum for the third series was identical with
that described in the second series. The successive inoculations
resulted in two spore generations being developed on Improved
Ligowa Oats (Minn, 281), one generation on A. sterilis, followed by
two generations on Improved Ligowa Oats (Minn. 281).

d) Rusted specimens of A. sterilis were collected at Lynchburg,
Virginia. The spores were used as the original inoculum. Sub-
sequent inoculations resulted in five spore generations being devel-

1921] HOERNER—GERMINATION 175

oped on Improved Ligowa Oats (Minn. 281), one on A. sterilis,
two on Improved Ligowa Oats (Minn. 281), followed by one
generation on A. sterilis.

e) Rust collected on A. sativa at Lynchburg, Virginia, was used
as the original inoculum. Subsequent inoculations resulted in five
spore generations being developed on Improved Ligowa Oats (Minn.
281), one on A. fatua, followed by two generations on Improved
Ligowa Oats (Minn. 281). :

f) Rusted specimens of A. fatua were collected at San Diego,
California. The spores were used as the original inoculum. Sub-
sequent inoculations resulted in thirteen successive spore genera-
tions being developed on Improved Ligowa Oats (Minn. 281).

g) Rust collected on A. sativa at Tallulah, Louisiana, was
used as the original inoculum. Subsequent inoculations resulted
in thirteen successive spore generations being developed on
Improved Ligowa Oats (Minn. 281).

Heavily rusted leaves were cut from plants in each series and
placed in Petri dishes. Germination tests showed the spores from
each series to be viable when removed from the greenhouse. The
following environmental conditions were provided:

A. Petri dishes were placed outside and protected by Pome
with about one foot of leaves and snow.

B. Petri dishes were placed outside and not afforded any
protection.

C. Petri dishes were wrapped in heavy ets paper and
placed i in a dark cabinet drawer, indoors.

D. Petri dishes were placed indoors fully exposed to sunlight.

Material from series a, b, f, and g was subjected to environment
A; from series a, e, f, and g to environment B; from series } and g
to environment C; from series c and g to environment D. Series
a, c, e, f, and g under all of the environmental conditions and series
g under environments A, B, and D gave no positive germination
tests. The germination tests from series 5 under all environments
provided, of series d under environment A, and of series g under
environment C were all positive. The temperature range for
environments out-of-doors was between —27°F. and 42°F. inclu-
sive, while for the indoors environments it was between 29° F. and

176 BOTANICAL GAZETTE [SEPTEMBER

86° F. inclusive. No consistent differences as to viability of spores
from various hosts and with different greenhouse life histories
were noted.

Specimens of rusted A. sativa were collected at Saint Paul,
Minnesota. Attempts were made to germinate spores at different
temperatures, which resulted in positive germination tests at rela-
tively low temperatures (about 7°C.), although apparently not
above 32°C. A temperature nie about 18°C. seemed to be the
optimum.

JOHNSON,’ in his germination studies of uredospores of crown
rust of oats, came to similar conclusions. He gave 7°-8°C. as the
minimum, 30°C. as the maximum, and 12°-17°C. as the optimum
for germination.

TELIOSPORE GERMINATION.—Uredinial material collected from
January 21 to April 20 on A. sativa and A. sterilis at Saint Paul,
Minnesota, was used as the original source of inoculum from which
sixteen different series of seedling oat hosts in the greenhouse were
infected. Plants of each series produced telia in abundance.
Negative results were obtained in all attempts to germinate these
teliospores. Rusted specimens of either A. sativa or A. sterilis
were collected from May 19 to May 2 of the year following, at
Baton Rouge, Louisiana, and Olivia, Rochester, and Saint Paul,
Minnesota. All attempts at germination gave negative results.

Summary

1. Aeciospores from herbarium specimens of Rhamnus were not
viable after a period of 167 days from date of collection.

2. Urediniospores from herbarium specimens of Avena sativa
proved to be viable as long as 87 days after date of collection.

3. Unprotected urediniospores lost their viability within 22 days,
with a minimum temperature, during this period, of —27°F. and
a maximum of 42°F.

4. When afforded protection with a temperature range similar
to the unprotected, these spores remained viable as long as 44 days.

5. Exposed to light, viability of urediniospores was lost within

3 Jonson, E. C., Cardinal temperatures for the germination of uredospores of
cereal rust. Phytdpath. 2:47, 48.

1921] HOERNER—GERMINATION 177

23 days, during which period the maximum temperature was 86°F.
and the minimum 29°F

6. Kept in the dark, urediniospores at similar temperatures to
those exposed to light, remained viable as long as 79 days.

7. Urediniospores germinated at a temperature as low as 7°C.,
with an optimum of 18°C., and a maximum of 32°C.

8. Teliospores developed on oat seedlings in the greenhouse and
not afforded a period of overwintering did not germinate.

g. Previous to overwintering and as late in the spring as May 2,
teliospores developed in the field were incapable of germination.

OREGON AGRICULTURAL COLLEGE
CORVALLIS, OREGON

CURRENT LITERATURE

MINOR NOTICES

Handbook of Yosemite National Park.—Hatt' has edited a volume of
information in reference to Yosemite National Park. He has also written the
chapter on trees, but the volume is really the combined product of more than
a dozen specialists, and appears to be decidedly superior to the handbooks
usually available for the guidance of travelers. The ideas sa policy of
actuating the best minds of the nation in the creation, administration, and use
of such parks are admirably set forth by SrEPHEN T. MaTHER, Directo United
States National Park Service.

Several professors of the University of California have contributed chap-
ters on their own subjects, KROEBER dealing with the anthropology, LAwsoNn
with the geology, GRINNELL with the animal life and its distribution according
to life zones, VAN DvkE with the insects, and Jepson with the plant life. All
these accounts are in attractive style and are scientifically accurate. JEPSON’S
chapter on the Sequoia seems to be particularly happy in presenting the life
problems of these great trees in attractive and accurate form. His treatment
of the wild flowers is based upon ecological principles, and here, in common
with the other chapters of the book, there is appended a sufficient bibliography
to lead the interested traveler or student into the available literature upon
the subject —Gro. D. Futter

Plant analysis.—Stechert and Company have recently republished GREEN-
IsH’s translation of DRracENDoRrF’s Plant analysis, qualitative and quanti-
tative.2—W™. CROCKER.

NOTES FOR STUDENTS

-Mutation.—For the past two decades the term mutation has held a very
prominent place in the vocabulary and thought of biologists, yet most of us
have had a very inexact understanding of the phenomena involved. Even
now an understanding of the causes is probably quite remote, but at least our

* Hatt, ANSELL T., Handbook of Yosemite National Park. 12 mo. pp. ix+347-
pls. 27 and map. New York: Putman’s Sons. 1921. $2.5

2 Dracenvorr, G., Plant analysis, qualitative and quantitative. pp. Bt ig
Translated by Henry G. GREENISH. 1883.

178

1921] _ CURRENT LITERATURE 179

knowledge of the characteristics of mutation are rapidly becoming more
accurate. Mutations were first ‘discovered’ by Dr Vries in O6enothera
Lamarckiana, and characterized as being qualitative, discontinuous, and con-
stant changes in the germ plasm. These three fundamental characteristics
still hold true, but some of DE Vrre’’ other ideas on the subject have been
considerably qualified by later work. For convenience the phenomena may
tentatively be classified under five heads. Information has come largely from
the published reports of a number of investigators, as indicated, and to some
degree is supplemented by papers delivered at the last meetings of the Ameri-
can Association.

1. Locus CHANGE.—These are changes restricted to a single locus of one
of the chromosomes. Usually they ate saecuve only on one ey rapeseed of a
pair, without affecting the on-

sequently the change first appears in the heterozygous condition. Baur3

“ce ”)
n

mozy
recessive to the previous condition. Only a very few dominant or “gai

the basis for progressive evolution. In the fruit-fly these changes take place
late in gametogenesis, since only one new individual of the new type appears
in a progeny. Baur, working on Antirrhinum, concludes that changes of
this sort take place more fccmeitie in the vegetative tissues than in connection
with gametogenesis, which should result in large numbers of the new type
among the progeny. In this respect it is quite probable that we are dealing
with fundamentally different situations in animals, where the germ cells are
differentiated so early in ontogeny, and in plants, where the germ cells are
merely late products of permanent growing points.

LENY‘ states that there is no periodicity to these mutations, thus
refuting one of the early ideas of De Vries. The same investigator demon-
strates that reverse mutations are more frequent than original mutations.
This, however, is simply because they are in the reverse direction, and not
because of their recent origin. In the case of these reverse mutations, the _
changes are always full jumps back to the original starting point, and never
result in an intermediate condition; nor will the selection of extreme types at
all modify the rate at which these reverse mutations occur. In the opinion
of the reviewer, however, this does not completely dispose of the possibility of
modifying the rate of mutation by selection (it seems quite possible that rate
of mutation might fall under the influence of multiple modifying factors).

3 Baur, Erwin, Mutationen von Antirrhinum majus. Zeit. Induct. Abstamm.
Vererb. 19:177-1093. figs. 10. 1918.

4 ZELENY, CHARLES, The direction and ireqhency of mutation in a series of
multiple alleiomorphs. Anat. Rec. 20:210-211. 1921.

180 BOTANICAL GAZETTE [SEPTEMBER

MULLER and ALTENBURG,S who have conducted a critical examination of
the fruit-fly for mutations occurring on the first and second chromosomes,
state that the vast majority of mutations have a lethal or semilethal effect
when present in the homozygous (recessive) condition. It is obvious, there-
fore, that a critical search for mutations must involve a very special technique.
MULLER is in possession of this technique through his intimate knowledge of
the linkage groups on the chromosomes in question, and his ability to detect
the absence of certain expected classes. On the sex chromosome he uncovered
the startling fact that 50 per cent of the mutations were located in a restricted
region at one end of the chromosome, which amounted to about 2 per cent of
its length as charted from cross-over values. It is an open question whether
this indicates a highly mutable region of the chromosome, or whether cross-
over values are an inaccurate index of length.

The most promising phase of MULLER’s work arises from this critical
study of the rate of mutation. Considering the whole length of the sex chro-
mosome, one mutation occurs in 106 gametes. For the second chromosome
the corresponding value is one in 175 gametes. ZELENY states that mutation
is as frequent in one sex as in the other. Having established these constants,
MULLER is now investigating the possibility of modifying the normal rate of
mutation. Already he has been successful in depressing the rate one-half by
means of low temperatures. Eventually such work may be of great practical
value. A knowledge of the conditions necessary for the maximum rate of
mutation should enable the pedigree culturalist to achieve much more rapid
results than otherwise.

2. DEFIcreNcy.—A rare phenomenon is described by BripcEs,® working
on the fruit-fly. This is more extensive than a simple locus change, being 4
“regional mutation,” a loss or “inactivation” of a portion of a chromosome.

LIC B

resulted in the appearance of an extra piece of chromosome which duplicates
in content a known region of the sex chromosome.

4. NON-DISJUNCTION.—This phenomenon, made famous through the
classic work of BRIDGES on the sex chromosome of the fruit-fly, may prove to
' be a fairly common occurrence. In an irregular reduction division one of the
chromosomes fails to ‘‘disjoin”’ seu from its mate. As a result, one or
two gametes are formed with an extra chromosome, and others which lack
this chromosome. The mating of one of the former with a normal gamete
would produce a zygote with an extra chromosome. BLAKESLEE, BELLING,

5 Mutter, H. J., and Atrensure, E., A study of the character and mode of
origin of eighteen mutations in the X-chromosome of Drosophila. Anat. Rec. 20:
213. 1921.

6 Bripces, CaALvin B., Vermilion-deficiency. Jour. Gen. Physiol. 1:645-656-
1919. :

1921] CURRENT LITERATURE 181

and FARNHAM? have discovered this phenomenon in Datura. The normal
diploid number of chromosomes in this form is twenty-four. Twelve different
“mutants” have been discovered with twenty-five chromosomes. This seems
to indicate that each of the twelve chromosomes (haploid) has failed to disjoin
at least once in history. These twelve new forms are abnormal in their vege-
tative features, and notably low in fertility.

ETRAPLOIDY.—A hurried or incomplete mitosis will sometimes result
in te simultaneous duplication of all of the chromosomes. This phenomenon
has been observed several times, and there are indications that it has taken
place frequently in the past. A general survey of the chromosome counts
emphasizes the fact that the haploid number is much more frequently an even
number than an odd one. This, together with the fact that there are several
species groups in which the chromosome count of some of the members is just
twice that of the others, suggests that tetraploidy may have played a con-
siderable réle in evolution. Tetraploidy commonly, but not always, brings
gigantism.

BLAKESLEE now puts the finishing touches on this tetraploidy conception
by more work on Datura. In addition to the abnormal forms with twenty-five
chromosomes, he has discovered one completely triploid (thirty-six) and
one tetraploid form. These latter both seem to be in a> “better balanced”
condition than the non-disjunctional (twenty-five) forms, since they are more
“normal” with respect to their vegetative features and fertility. The beauty
of the situation arises from the fact that the tetraploid type contains a pre-
viously known Mendelian factor. In normal forms a hybrid of the compo-
sition Aa will give a 3:1 ratio of purple- and white-flowered in the F,. The
tetraploid form AAaa gives gametes in the ratio 14 A:4Aaz1aa. These
recombine to produce an F; of 35 purple:1 white. The F; and later generations
behave according to expectations on this basis.

A question of terminology now arises. Of these various.types of germinal
changes, it seems the consensus of opinion to restrict the term mutation to the
locus change. This is undoubtedly the most frequent type of change to =
place, and possibly the most effective single factor in evolution. Deficienc
and duplications are very rare at best. Non-disjunction and Siacr 5 are
probably fairly common, and the latter is doubtless very important in evolu-
tion. These last two (and panes Laces as well) may be referred to
collectively as “chromosome aberra

this differs from maging as originally described by DE VRIEs.
This is not surprising in view of the fact that the original example of muta-
tion was not a true case of mutation at all; it now seems certain that O. Lamarck-
iana is a hybrid, and its “mutants” merely recessives being segregated out.

? Braxestits, ALBERT F., BELLING, JOmN, a0 and Farnuam, M. E., Chromosoma
duplicati ‘ ts. Science 52:388-390. 1920.

182 BOTANICAL GAZETTE [SEPTEMBER

Mutter’ deserves the credit for solving this vexing problem. -In the fruit-fly
he discovered an essentially true-breeding hybrid race, and explained it by
a system of balanced lethal factors. These factors assert their lethal effect
only when they occur in the homozygous recessive condition. In this
race of flies, two such factors are present in heterozygous condition on the
same pair of chromosomes, the dominant members of the heterozygous sets
being on the opposite chromosomes of the pair. Such a hybrid continues
€ a 0)

to the progeny. The recessives of any heterozygous set on this same
chromosome pair will remain concealed when the stock is allowed to in-
ree ccasional crossing-over will cause the appearance of a few (but
in predictable frequencies) of these recessives, like the ‘‘mutants’’ thrown by
O. Lamarckiana

t is Siseceatlie to note that Dr Vries? himself now subscribes to
bout

with the charactef factor. Heterozygous combinations give good seeds,
homozygous give sterile. If one of the two lethal factors become “vital,”
the O. Jaeta or O. velutina mutation appears.—M. C. CouLTER.

axonomic notes.—Miss BurLINGHAM®” has described five new species of
Russula from Vermont and one from Massachusetts, most of which seem to
be rare.

ScHLECHTER™ has revised two African genera of the Orchidaceae, Schizochi-
lus and Brachycorythis. In the former genus he recognizes twenty-five species,
thirteen of which are new; while in the latter genus twenty-three species are
recorded, four of which are new. He also establishes two new genera, Gyala-
denia and Diplacorchis.

MovrRILL,” in continuation of his investigation of Polypores, has pub-
lished an account of some of the resupinate forms which are rose-colored, lilac,
red, or purple. He presents twenty-six species of Poria, five of which are

H. J., Genetic variability, twin hybrids, and constant hybrids, in 4
case of balanced lethal factors. Genetics 3:422- . £. £018.
9 DeVries, H., nie hue senaionsn un ghibpenwelie Artbildung. Flora 11-12:
208-226. 1918
bad Buxrmtasan, GERTRUDE S., Some new species of Russula. Mycologia 13: .
129-134. pl. 7. 192
SCHLECHT oer Revision der Gattungen Schizochilus Sond. und Brachycorythis
Ldl. Beih. Bot. ponent 38:80-131
™ Murrityt, Wititam A. ,Light-coloed jeenbate Polypores. III. Mycologia
13:83-100. 1921.

199t} .< CURRENT LITERATURE 183

described as new. In a later publication he considers the resupinate forms
in which yellow is the predominant color, presenting sixteen species of Poria,
seven of which are new.

BLAKE” has revised four genera of Compositae (Asteraceae) which are
restricted in their distribution to the tropical and subtropical portions of
North and South America, as follows: Acanthospermum (eight spp., three new),
Flourensia (twenty-three spp., five new), Oyedaea (twelve spp., three new),
and Tithonia (ten spp.). The revisions include full bibliography and lists of
collections.

KAUFFMAN'S has described a new genus (Isoachlya) of Saprolegniaceae,
which is chiefly distinguished “by the presence of the cymose or Achiye
mode of formation of secondary sporangia, coupled with diplanetic zoospores.”’
It includes three species, one of ou is new, the other two being trans-
ferred from Achlya and Saproleg

Naxkar® has published a detain monograph of the Pepcicliacess of
Japan, including 7 genera, 91 species, and 33 ahora Phere the 15 new
* species, there are numerous transfers frctdvtig new 1.

Kuno” has published an enumeration of the Lables. 3 the Kurile Islands
and Yezo Island, with full bibliography and citation of collections. The list
includes 38 species, 7. among 21 genera. A new species is described
in Teucrium and in Scute

Brirron and Fase dese described a new genus (Neoabboitia) of Cacta-
ceae, a treelike form previously named Cactus paniculatus Lam., and later
Cereus paniculatus DC, It is a monotypic genus of Hispaniola, Aciliestad to
Dr. W. L. Assotr.—J. M. C.

Physical properties of protoplasm.—SerIrriz® has carried out microdis-
section of protoplasm from a number of lower animals and plants, and his
work leads to the following conclusions. (1) There is a plasma membrane on

, Light-colored resupinate Polypores. IV. Mycologia 13:171-178. 1921.

4 BLake, S. F., Revisions of the genera euenap gta Agar Ovyedaea,
and Tithonia. Contrib. U.S. Nat. Herb. 20: 383-436. pl. 23.

*s KauFFMAN, C. H., Isoachlya, a new genus of the iis Amer.
Jour. Bot. 8:231-237. pls. 13, 14. 1921

% NAKAI, TAKENOSHIN, Touhase systematis Caprifoliacesrum Japonicarum.
Jour. Coll. Sci. Tokyo 43: art. 2. pp. 139. 1921.

7 Kupo, Yusuun, Enumeratio Labiatarum specierum varietatum fo: que
in Insulis Kodlontbus et Insula Yezoensi sponte nascentium. Jour. Coll. Sci. Tokyo
_ 43: art. 8. pp. 509. pls. 2. 1921.

78 Britton, N. L., and Rose, J. N., Neoabbottia, a new cactus genus from His-
paniola. Smithson. Miscell. Coll. 72: no. 9. pls. 1-4. 1921.

9 SEIFRIz, W., Observations on some physical properties of protoplasm by aid of.
microdissection. Ann. Botany 35:269-296. 1921.

184 BOTANICAL GAZETTE [SEPTEMBER

the surface of all protoplasm; (2) physical considerations lead to belief in a
) plasma

s; (4) the membrane is of high viscosity, probably a gel, which readily
reverts to a liquid sol state; (5) it is capable of ready adjustment to changes
in contour and area; (6) protoplasm in most cases forms a membrane almost
instantly on the surface; exceptions are due to extreme liquidity; (7) the
living membrane is rather delimited from the inner plasma, but it cannot be
isolated from it; (8) the degenerated, coagulated plasma membrane can some-
times be isolated, being then of finer consistency, elastic, and exceedingly
tough; (9) the nucleus and vacuoles also possess protoplasmic membranes
resembling the-outer plasma membrane; (10) the thickness of the membrane
is probably about 0.1

Protoplasm, when dissected i in water, in most cases is immiscible in it.
When it is miscible, it is caused by extreme liquidity or disintegration. The
immiscivity is possibly due to the colloidal and chemical nature of the proto-
plasm. The absorption and retention of water by protoplasm are essentially
inhibition processes—Ww. CROCKER.

Food storage in cotyledons.—DuccArR” has found that removal of the
cotyledons of the pea seedling at an early stage of growth causes a much slower
development of the plant, but their removal after the food is largely withdrawn
causes no reduction in growth rate. Removal of the endosperm of the corn
has far less effect. Glycocoll and sodium nucleinate in water culture partially
substitute for the loss of the cotyledons. Asparaginate and alanin depress

e growth with cotyledons removed. The author is to run experiments in
sterile conditions to further test the possibility of organic materials substituting
for the cotyledons —WM. CROCKER. :

Disease resistance.—McLEAN*™ concludes that Szinkum mandarin is
resistant to citrus canker because its stomata are of such shape as to exclude
liquid water and thus stop the entrance of the motile bacterium that produces
the canker. The Florida seedling grapefruit which is susceptible to this

_ disease has stomata of about the same size, but they are of such shape as to
permit the accumulation of liquid water in the stomata and allow the entrance
of the bacterium.—Wa. Crocker.

Duccar, B. M., The nutrition value of food reserve in cotyledons. Ann. Mo.
Bot. Gard. 7:291-298. 1920

at MCLEAN, F. T., A ee of the structure of the stomata of two pet of es
in relation to the dines canker. Bull. Torr. Bot. Club 48:101—106.

—
VOLUME LXXII NUMBER 4

tHE
DOTANICAL GAZES

OCTOBER 1921

SEXUAL DIMORPHISM IN CUNNINGHAMELLA

ALBERT F. BLAKESLEE, J. LINCOLN CARTLEDGE, AND
DoNnaALtpD S. WELCH

(WITH ONE FIGURE)
Introduction
HETEROTHALLIC AND HOMOTHALLIC FORMS

In 1904 (1) it was shown that the mucors can be classified into
two main groups according to their ability to produce zygospores
from the sowing of a single spore. Species which are able to form
sexual spores by the conjugation of branches from the same plant
were called homothallic, since the mycelia appeared to be sexually
alike; those which were able to form sexual spores only by the
interaction of different plants were called heterothallic, since the
mycelia taking part in conjugation appeared to be sexually different.
The terms homothallic and heterothallic were used instead of
hermaphroditic and dioecious because at the time they were first
Suggested our knowledge of sexuality in the mucors did not seem
to warrant unreservedly accepting the idea of a strict sexual
dimorphism in these forms, although such a dimorphism was
strongly indicated by the interaction which had just been dis-
covered between plus and minus races.

In later publications (5, 6) the desirability was pointed out of
extending the use of the terms homothallic and heterothallic to
signify the type of sexual differentiation in all gametophytes, in
contrast with the terms homophytic and heterophytic suggested

185

186 BOTANICAL GAZETTE [OCTOBER

for sporophytes. It was not expected that these terms would
supplant the more familiar words hermaphroditic and dioecious.
They may be found useful in bringing about greater accuracy in
sexual terminology, and in emphasizing the inconsistency of calling
a form like Marchantia dioecious and a form like the common lily
hermaphroditic, when the two belong to the same sexual type.

EVIDENCE FOR SEX INTERGRADES IN HETEROTHALLIC SPECIES

It is well known that sex intergrades are relatively frequent
in sporophytic plants like the willow and hemp, which are commonly
classified as dioecious. Similar sexual abnormalities, therefore,
have been expected and sought for in heterothallic mucors ever
since heterothallism was discovered in these forms in 1903. The
fact that no race of a heterothallic mucor™ has been found by the
writers which, if it gave any sexual reaction at all, behaved otherwise
than as a plus or a minus, indicates that sex intergrades in these
forms are at best extremely rare. It is true that a number of
investigators have reported findings which they have interpreted as
opposed to the existence of a strict sexual dimorphism in the bread
molds and related forms. Despite the fact that their conclusions
were in harmony with our expectations based upon the condition
in higher forms, the instances of supposed sex intergrades in hetero-
thallic species are either isolated observations of two conjugating
filaments which seem to originate from the same hypha, or have
been supported by experimental evidence open to criticism. The
inadequacy of the evidence has been pointed out in earlier publi-
cations (4, 7, 8), but it seems appropriate to mention two examples
more or less typical of their kind. The first case is cited by Miss
McCormick (15), and is illustrated by a figure showing a partially
matured zygospore with the suspensor on one side arising from a
filament which curves over and connects with the filament from
the suspensor on the other side. In reply to an inquiry in regard
to this zygospore Miss McCormick has written that after the

* The peculiar homothallic mycelium produced by regeneration of the germ tube _
and at times produced from the germination of spores in the germ sporangium in
Phycomyces (3) is a temporary condition only, and apparently should more properly

be considered a mixochimera of plus and minus protoplasm, as BurcErFF (13) suggests,
than as a sexually constant race.

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 187

drawings were made the homothallic strand was lost in an attempt
to make a permanent mount of the fresh material. So far as we are
aware, such a condition as Miss McCormick figures has not been
described elsewhere for Rhizopus since 1903, when heterothallism
was first discovered in the mucors. Inasmuch as an enormous
number of zygospores of Rhizopus must have been observed more
or less closely during this time, since it is a common type for labora-
tory study (Miss McCormick herself [16] reports having examined
over 2000 in her cytological investigations in this species), it appears
reasonable that in an isolated instance of this kind, the filaments
from the two sides of the zygospore which appeared to be connected
may in fact have been separate, but the place of separation obscured
by overlying hyphae. That it is unsafe to judge of the thallic
condition of a species from the hyphal connections is shown by
experience with a class of students who were studying Rhizopus
shortly after heterothallism had been discovered in other mucors,
but before it had been demonstrated for this species. They were
asked to find cases in which both the suspensors originated from
branches of the same filament. A number of cases were found in
which the two suspensors actually seemed to be connected, but in
every instance there were one or more overlying filaments which
would render the condition open to doubt by a critical observer.
The second case is a paper by NAMYsLowskKI (17), in which he
throws doubts upon heterothallism in the whole group of the mucors.
His experimental evidence comes from isolating single spores of
Rhizopus and sowing the resulting mycelia on bread. The appear-
ance of zygospores in fourteen out of forty-six such single spore
cultures led him to conclude that his Rhizopus was homothallic.
As has already been pointed out (7), the facts that six of these
cultures were destroyed by bacteria and that thirteen more were
devoid of even sporangia and hence probably also infected with
bacteria, rendered it probable, to one familiar with pure culture
methods, that the zygospores which NamysLowski obtained in
part of his cultures from the sowing of a single spore actually might
have arisen through interaction with the opposite sex which had
gained access to these cultures through infection. This explanation
seemed later confirmed by the isolation of the two sexual strains

188 BOTANICAL GAZETTE [OCTOBER

from zygosporic material which Namystowsk! kindly sent to one
of us. NamySsLowskI (18), however, still believes, upon evidence
which we have criticized, that heterothallic species have been
shown capable of producing homothallic zygospores.

The two examples given are typical of less careful observations.
Although cases of homothallism in heterothallic species on a priori
grounds were to be expected, we have never found them ourselves,
and could not feel that the reports of them by other investigators
could stand critical examination. It reminded one of the reports
of the birth of a full black negro baby from pure white parents
which from time to time have appeared in literature and been
passed on by rumor, but which have in no case been confirmed
by students of human heredity.

BURGER ON CUNNINGHAMELLA

The condition outlined was the situation in the early part of
1919, when BURGER announced the finding of hermaphroditic as
well as “pseudo-heterothallic’’ strains in Cunninghamella and
Syncephalastrum. At the same time report came from one of the
laboratories of the Department of Agriculture of a strain of Rhizopus
which would form zygospores with both plus and minus test strains
of this species. As to the Rhizopus, it was found upon inquiry that
this particular strain had died out, and that after all it had not shown
the capacity of conjugating with both the opposite sexes. BURGER’S
paper on sexuality in Cunninghamella (14) presents the most exten-
sive evidence which has yet appeared for sex intergrades in any
heterothallic mucors. Although his arguments from the data pre-
sented seemed open to some criticism, his publication made the genus
Cunninghamella the most likely source known for sex intergrades, the
investigation of which would have considerable genetic interest. —
Recently published studies by one of us (11) had shown that races
with plus and races with minus tendencies can arise by mutation
from a homothallic species, and that such a race may cease to form
zygospores and take on the appearance of a heterothallic species.
It seemed worth while, therefore, to look for races with homothallic
tendencies among heterothallic species, in view of BuURGER’s paper.
Accordingly, a rather extensive study of the interaction of strains

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 189

has been made for four species of Cunninghamella, the details of
which will be given later. Since they offer no support to BURGER’s
conception of hermaphroditism in the genus, and since his cultures
were allowed to die out before his final results were published,
making it impossible for his material* to be retested, it is necessary
to subject both his experimental technique and conclusions to —
searching criticism in lieu of other means of judging of the correct-
ness of a statement which runs counter to the experience of most
careful workers on the Mucorineae. BURGER’s paper will be con-
sidered before discussing the results of this investigation.

BurGER found great irregularity in the sexual behavior of races
of C. bertholletiae. While some races were consistently either plus
or minus-in reaction, others appeared to react both as plus and
minus with properly chosen test strains. Certain races seemed to
form a sexual triangle. His race A, for example, would form
zygospores with B, race B would form zygospores with C, race C
would form zygospores with A, and the family triangle was complete.

BURGER’s conclusions are based primarily upon tests with
twenty-six? races of C. bertholletiae. Since he says ‘authentic
cultures of C. bertholletiae and C. elegans were obtained from
Holland,” and later credits us with having sent the only race of
C. elegans which he used in his tests, there is little doubt that his
race no. 21 of C. bertholletiae is identical with the no. 213 which we
secured from the Centralstelle, and of which we sent a subculture
to the Harvard laboratory with C. elegans shortly before BURGER
used the strains in his investigations. In addition to these two
races, he used the plus and minus strains of C. echinulata and of
Mucor V, which had also been sent by us to the Harvard laboratory.
The sexual races of these two species were contrasted with all his
twenty-six races of C. bertholletiae, but without finding any “imper-
fect hybridization” reactions. The race of C. elegans and six races
of C. bertholletiae were individually contrasted with the remaining
races of a collection consisting of twenty-six races of C. bertholletiae,
five races of C. echinulata (including our plus and minus strains),

2 Except his race no. 21, which will be discussed later.

3In two places in the text (probably through error), his race no. 25 is called
Mucor V minus.

Igo BOTANICAL GAZETTE [OCTOBER

and plus and minus strains of Mucor V and the plus strain of
C. elegans. The positive and negative results are assembled in a
table. The sexual condition seemed to BurGER so hopelessly
confused that he was led to the following conclusions contained
in his summary:

1. In Cunninghamella there does not exist sexual dimorphism.

2. C. echinulata plus and minus, or Mucor V plus and minus as separated
by BLAKESLEE, are unable to form progametes or gametes when contrasted
with any one of twenty-six cultures of C. bertholletiae.

any of these cultures of C. bertholletiae were able to form zygospores
whines: contrasted with certain other cultures of this same species.

4. There exists a selective power in some strains to form zygospores with
certain other strains. This condition of pseudoheterothallism cannot be ex-
plained at present

5. There exists a condition in some strains which might be called hermaph-
roditism

6. in none of the hermaphroditic strains did branches of the same hyphae
conjugate.

7. Zygospores were produced only when two strains were contrasted whose
gametes were compatible.

It will be well to examine this summary to see whether the
rather sweeping conclusions are warranted from BURGER’S own
data, assuming for the moment that these data are not open to
criticism. The results of his contrasts are more readily compared
if his table be rearranged as shown in table I. The six testers of
C. bertholletiae are placed at the top, together with the plus race of
C. elegans and of Mucor V, which were also used as testers. On
the side, grouped according to sex, are placed the twenty-six races
with which the testers were contrasted; H stands for imperfect
hybridization, Z for zygospores. If the latter is inclosed in paren-
thesis, it indicates the occurrence of zygospores in a contrast where
they would not be expected on the basis of a strict sexual dimor-
phism. No grades are given in table I, since none are presented
in the original paper.

The sexual behavior of the twenty-six races of C. bertholletiae
shown in the table I is not so badly mixed as even BuRGER himself
was apparently led to believe from his method of analyzing the

‘data. He says: “Nos. 1 and 2 have always remained constantly

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA Iol

plus, while nos. 4-6, 12, 15, 18, 19, 22-26 were always minus, nos.
3, 7-11, 13, 14, 16, 17, 20, 21, . .. , however, have reacted with
both the so-called plus and minus strains.’”’ This is a curious
conclusion, that nos. 1 and 2 are constantly plus because they

TABLE I

REARRANGEMENT OF DATA IN BuRGER’S TABLE I: Cunninghamelia bertholletiae,
26 RACES (1-26); NUMBER OF COMBINATIONS POSSIBLE, 325; NUMBER OF COM-
BINATIONS MADE, 135; ABERRANT COMBINATIONS, 6; ‘‘ PSEUDOHETEROTHALLIC
HERMAPHRODITIC RACES,” 3 TO 8; Z STANDS FOR OCCURRENCE OF ZYGOSPORES,
H FOR OCCURRENCE OF “IMPERFECT HYBRIDIZATION’? REACTION; PARENTHESES
INDICATE THAT REACTION IS ABERRANT ON BASIS OF SEXUAL DIMORPHISM

9 plus t4 plus} 34 7 minus| 3 min

Races contrasted yao od to plus or i gone IV oe oie a tyne

minus mete plus] Sora minus | minus
us or plus and minus 9...|...... oO O O O Z Z Z
Plus rife fete aban, @ Mel Piha O O O z Zz Z
Plus or plus and minus 14...| O gel Cl ae 2 O Z Z Z
Plus or plus and minus 16...|. O O12) O O z if Zz
us soy Se meas 8 Oo O O O Z on ee
Plus or plus and minus ~ (Z) O (Z) O oO re fe Z
Plus fap O O O O Oo v4 O O
d = oh O O O O O z O O
fade O O O O 0 0 O L

eraceplneins minus 3...) Z Z H oO (Z) 2G ia
inusorplusandminus 7...) Z Z oO oO AS aes oO
: ae Zz Zi: H O 0 oO O
Minus 12.47 2 Z H O oO O Oo
Minusorplusandminus 13...| Z Z H Oo} (@) 18) O
Minusorplusandminus 21...| Z Z H i De ee ee (Z)| (Z)
us m= Z O O O O oO O
Minus 5 Z O ) O O O O O
nus 6 2 O O O O O O Oo
nus 15 Z O O O O O O O
nus 18 oO 2 O oO Oo O O O
nus 10.. O Z O O O O O O
nus 22... O z O O O 0 O O
nus Pie ae 8 Z O oO O O O O
nus 4 O O H O O O O
nus euch OO O ) H O O O O
nus 20.612: 0 O O H O O oO O
minus] 32...| O 0:10 Hi Zz Oo O O

produced zygospores with a hermaphrodite (no. 21) and with no
other race; while no. 11 is listed among those which have reacted
with both the so-called plus and minus strains when it formed
zygospores only with no. 3, which need not be considered other than
as a good minus. Burcer further believed that there were twelve
hermaphrodites, since he lists this number, including no. 11 among

192 BOTANICAL GAZETTE [ocroBER

those reacting with both plus and minus strains. Referring to
table I, it will be seen that in only eight contrasts are zygospores
found where under a strict sexual dimorphism they would not be
expected. Two of the eight are duplicates, leaving only six dif-
ferent contrasts showing aberrant reactions. It is not necessary,
however, to consider more than three races hermaphroditic to
account for the aberrant results. These three hermaphrodites may
be variously chosen. Race no. 21 has three aberrant reactions,
which is the largest number shown by any race. Both races nos.
14 and 20 show two aberrant reactions each, and may be chosen
with no. 21 to make up the three hermaphrodites. Since nos. 14
and 20 are both assumed to be hermaphrodites, the reaction between
them ought not perhaps to be credited to both of these races. How-
ever the credit of aberrancy is adjusted between nos. 14 and 20,
race no. 21 remains the one which gives the largest number of
aberrant reactions, and therefore of all the twenty-six races it is
the one most surely shown by BurGER’s data to be a hermaphro-
dite. This no. 21 is the same as our no. 213, and is the only one
of the twenty-six races which it has been possible to reinvestigate.
Its sexual behavior will be discussed more fully later.

Conclusion no. 1 of BURGER’s summary that in Cunninghamella
there does not exist sexual dimorphism would seem too sweeping
a statement in view of the fact that in Mucor and Absidia, which
are predominantly heterothallic, forms are known, such as Mucor
heterogamus (which with other similar species has been placed by
some workers in the genus Zygorhynchus), and Absidia spinosa,
which are homothallic. Races of two other species of Cunning-
hamella reported upon in the paper under discussion gave no
evidence of hermaphroditism, and in consequence the data pre-
sented warrant the conclusion at most in reference to a single
species. That in this single species three out of twenty-six races
showed, in 135 out of a possible 325 contrasts, six reactions which
were interpreted as indicating hermaphroditism, would render the
species in the same class with the willows and others of the flowering
plants called dioecious. That sexual dimorphism, strictly speaking,
does not exist in higher plants is strongly suggested by past obser-
vations and experimentation, but the term sexual dimorphism is

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 193

currently applied to the so-called dioecious condition in forms like
the willow, despite the familiar exceptions.

Conclusion no. 2, that the sexual races of C. echinulata and
Mucor V as separated by us are unable to form progametes with
any of the twenty-six races of C. bertholletiae studied, is too sweep-
ing a statement, and will be shown later to be incorrect. In place
of “are unable to form” should have been written ‘have not been
observed to form’’ progametes.

The statements of fact in conclusions nos. 3, 4, and 7 are what
one could make in regard to a heterothallic species. Conclusion
no. 5, that a condition of hermaphroditism exists in some strains,
seems somewhat opposed to the fact brought out in no. 6, that
these hermaphrodites do not themselves take part in conjugation
when growing alone in pure cultures, ‘‘a fact which indicates that
this species is not homothallic,”’ according to BuRGER. “Homo-
thallic” it will be remembered is a term used by us to indicate a
hermaphroditic condition in gametophytes. The line of reasoning
is as follows: some strains are hermaphrodites, in none of the her-
maphroditic strains did branches of the same hyphae conjugate,
therefore the species is not hermaphroditic.

Earlier in the paper the fact that the stock tubes containing the
individual twenty-six races did not produce zygospores under
nutrient and temperature conditions favorable for their formation
showed according to BurGER “that the cultures were pure and
not a mixture of strains.’”’ On the contrary, BURGER’S own data
show that lack of zygospore formation cannot be a proof of freedom
from mixture of strains. Table I makes the matter clear. The
minus race no. 4 fails to form zygospores with the plus race no. ro.
If nos. 4 and 10 were mixed in a tube culture, therefore, they would
not be expected to form zygospores, and yet the plus component
(no. 10) of this mixture would form zygospores with the minus races
3, 7, 8, etc., while the minus component (no. 4) would form zygo-
spores with the plus races nos. 9 and 14. The tube containing the
mixture suggested would be able to conjugate, therefore, with both
plus and minus strains, and such a reaction is BuRGER’S proof of
hermaphroditism in Cunninghamella. ‘Table I shows that eighteen
out of the twenty-six races could be mixed to form twenty different

194 BOTANICAL GAZETTE [OCTOBER

combination pairs capable of reacting with both plus and minus
races. If all of the 325 possible contrasts had been made between
the twenty-six races instead of only the 135 actually attempted,
it is probable that a considerably larger number of pairs of races,
capable when mixed of producing zygospores with both plus and
minus races, would be evident. So far as the data of BURGER go,
however, they are sufficient to show that absence of zygospores in
a culture cannot be offered as proof that it is not a mixture of
strains; and to indicate that infection, if it occurred, rather than
the existence of pseudoheterothallic hermaphrodites, might be the
cause of zygospores in cultures where they would not be expected
on the basis of sexual dimorphism.

BuRGER believed he had eliminated the possible objection that
his cultures had been mixed by making several single spore cultures
from each of the strains nos. 9, 3, and 21, and obtaining zygospores
whenever such cultures from one of these strains were contrasted
with those from either of the other two strains. The test, on the
face of it, may appear to be a critical one, and in fact if only these
three strains had been kept in cultivation they would now afford
an opportunity of critically retesting data upon which BURGER’S
theories are based. Since, however, these cultures were destroyed
before the publication of his paper in which their peculiar behavior
is described, it will be necessary to depend upon circumstantial
rather than upon direct evidence. As seen from table I, nos. 9
and 3 may be considered good plus and minus races, and in conse-
quence should be expected to give reactions when grown together.
In consequence, interest centers rather in strain no. 21. This race
it will be remembered gave the most aberrant reactions, and
together with nos. 14 and 20 is able to account for all the evidence
that can be brought forward in support of BuRGER’s theory 0
pseudoheterothallism. No 21 is predominantly minus and so
should be expected to give reactions with the plus strain no. 9.
The abnormal reaction, therefore, is between nos. 21 and 3. The
surprising thing about these tests is that apparently there were no
controls. Each of the three single spore cultures of no. 3 were
contrasted against each of the four single spore cultures of no. 21,

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 195

but nothing was said about control contrasts between the sub-
cultures of no. 3, nor of contrasts between the subcultures of no. 21,
nor is mention anywhere made of uninoculated controls to discover
what the danger might be from air infection of spores of the oppo-
site sexes. For aught we know, single spore subcultures of_any
race might have appeared to produce zygospores when contrasted
together at the time BURGER made his single spore cultures, which
was apparently at the end of his series of contrasts with the twenty-
six races. Neither in these single spore culture contrasts nor in
any of the others is the abundance of zygospores graded. A single
zygospore or a limited number which might make the investigator
suspicious of mixture of strains in his stock culture or of infection
in his contrast culture apparently have been classified as of equal
value with our grades A and B

In a previous paper (12) attention was called to the peculiar
danger of air borne infection of Cunninghamella when forms of
this genus had previously been grown in the laboratory. Cunning-
hamella, it may be remembered, was first described as an Oedo-
cephalum, a hyphomycetous genus with exogenous spores, but was
later (2) shown to be a heterothallic mucor by the isolation of its
sexual races and their combination to form zygospores. It has
already been shown that another investigator who found zygo-
spores in his cultures after planting the mycelia from single spores
Was apparently misled into a theory of hermaphroditism for
Rhizopus on account of unsuspected infection of his cultures with
sexual races of the same species. It seems reasonable to suspect
that BurGER has fallen into a similar error, since he gives no evi-
dence to the contrary, rather than to believe he has discovered a
sexual condition unparalleled in the experience of other critical
workers.

There are a number of perhaps minor matters in the body of
BURGER’s paper, such as the use of the terms neutral and zygo-
tactic, to which objection might be made. Enough has been said,
however, to indicate that his data do not inevitably lead to
his main conclusion of pseudoheterothallic hermaphroditism in
Cunninghamella.

190 BOTANICAL GAZETTE LOCTOBER

BURGER’S CONCLUSIONS COMPARED WITH NEW DATA

It will be remembered that of the cultures used by BURGER,
Cunninghamella echinulata plus and minus, C. elegans plus, Mucor
V plus and minus, and his race no. 21 of C. bertholletiae were obtained
from us. These races are still running, and it has been possible
therefore to compare their behavior with the observations of
BURGER on the same material.

The second conclusion in his summary, to the effect that neither
the sexual strains of our C. echinulata nor those of our Mucor V
are able to form progametes with any one of twenty-six cultures
of C. bertholletiae, is contrary to our experience. Table II shows

TABLE II
“IMPERFECT HYBRIDIZATION” BETWEEN RACES OF Cunninghamella bertholletiae AND
Mucor V pus AND MINUS; Mucor V PLANTED 4:00 P.M., 11/19/19; C. berthol-

nested PLANTED I1:00 A.M., 11/20/19; RECORDS seas 2:00 TO 4:00 P.M
11/22/19; NUTRIENT NO. 380 (BURGER’S OATMEAL AGAR); c AND d_ INDICATE
GRADES OF IMPERFECT HYBRIDIZATION; O INDICATES ABSENCE OF OBSERVED

REACTION
Neutral .
Plus races oe Minus races
C. bertholletiae
217 | 227 | 268 | 234 | 464 | 456 | 215 | 452 266 | 457 | = 213 ose
ssa aa O101.01-0101,0) 6104 tie ci8
cor V minus..| c c eroro, oro; 0 3 01 0

the results of contrasts between the sexual races of Mucor V and
testers from the collection of races of C. bertholletiae grown on
oatmeal agar made up according to BURGER’s method of prepara-
tion. The majority of the races (including no. 213, which is
BURGER’S no. 21) showed “imperfect hybridizations” with the
opposite sex of Mucor V. The nutrient chosen does not appear
to be the best for the reaction, but was used to make the conditions
of the experiment so far as possible comparable with those reported
in the paper under discussion. ‘Imperfect hybridization’’ between
Mucor V plus and our race no. 213 has been obtained on other
nutrients, but the reaction with this particular race has never been
strong and might readily have been missed had we employed @

less successful method of observation (12).

1921] BLAKES LEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 197

Our old test races of C. echinulata (nos. 885 and 886) are able
to form ‘‘imperfect hybridization” reactions with a number of the
races of C. bertholletiae, although no sexual reaction between them
and our race no. 213 has been observed.

Our race no. 213, which is the same as BURGER’s no, 21 and
is the strain which furnished the strongest evidence for his theory
of pseudoheterothallic hermaphroditism, has been tested against
eighty-eight other races of the same species obtained from Brazil
nuts from various localities. In all these tests it has reacted, if at
all, only as a minus. In BuRGER’s experience, although predomi-
nantly a minus, it produced zygospores in three combinations with
the seventeen other minus races, a total of 17.5 per cent of the
contrasts between it and other minus races. If it had reacted in
‘the same manner we should have expected it to produce zygospores
with a.minimum of eleven of our sixty-eight other minus races.
As a matter of fact, it showed reactions with none of these minus
races. That so great a difference really exists between our minus
strains and those studied by BURGER seems unlikely.

BURGER seems not to have observed the imperfect sexual
reactions between races of C. bertholletiae which failed to carry
through to zygospore formation. Partly for this reason perhaps,
despite his own evidence already adduced to the contrary, he failed
to appreciate the fact that absence of zygospore formation in a
culture is not a- proof of its freedom from mixture with strains of
the opposite sex. The imperfect reactions in C. bertholletiae will be
discussed later. In our experience the plus race no. 465 forms only
imperfect reactions with the minus race 457. In consequence,
when these two races are planted mixed in a Petri culture in con-
trast with the plus race no. 217 and the minus race no. 459, a
triangular reaction has been obtained, as shown in fig. 1, where the
mixture is represented as forming zygospores with both the plus
race no. 217 and the minus race no. 459, while the latter two are
also forming zygospores together. Although we have obtained
the triangular reaction shown in fig. 1, which BuRGER considered
a proof that sexual dimorphism does not exist in Cunninghamella,
we know in this case that the reaction is due to a mixture of
strains and not to pseudoheterothallic h phroditi BURGER’S

198

BOTANICAL GAZETTE

[OCTOBER

conclusions, therefore, are not justified from ‘his own data, and
the few races which it has been possible to retest from among

Mixture of :
“he 46504) & 467(-) a

seer

459(-) 217(+)

G. 1.—Diagram Edens
a dish culture: at lower right
and left were planted secidini

those studied by him have shown
either reactions which he considered
impossible or have failed to show the
reactions which he found and upon
which his theory of pseudohetero-
thallic hermaphroditism in Cunning-
hamella was based. It must be em-
phasized, however, that despite the
necessity for considering the evidence
for sex intergrades in heterothallic
mucors open to serious criticism, there
is no proof at hand that such inter-
grades do not exist. A somewhat

detailed consideration of the evi-
dence for them in Cunninghamella has
been given to indicate a few of the
dangers into which even one with some
experience with cultural methods is
likely to fall. The data already pub-
lished (10) and to be presented in
the following pages show that sex intergrades must be extremely
rare in the mucors, and place the burden of proof on observers
who think they have found evidence for their occurrence.

h are formin

(represented by dots at line of con-
tact between them); in upper third
was planted a mixture of plus and
minus races 465 and 457 which
fail to form zygospores with each
other, but form them with the re-
spective opposite sexes 459 and
217.

New data on Cunninghamella

Tests of the sexual condition in Cunninghamella were made with
202 races of four species; forty-two races of C. elegans, eighteen races
of C. echinulata, eighty-nine races of C. bertholletiae, and fifty-three
races of a species as yet unidentified.4 The method of running the

4 The discrepancy between the number of races given here and that listed in a
previous publication (10) is due to the separation of Cunninghamella A from the other
species and the omission of four races ftom the tables on account of infection in the
stock tubes, because of incomplete records or for other reasons. All told; including
tests with other genera, a considerably larger number of contrasts has been made with
Cunninghamella than is reported.

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 1099

gross cultures to obtain the races to be investigated, as well as the
detailed methods of making contrasts between them has been
described in a previous publication (12) and need not be repeated
here. Table III gives the origin of the different races used in
the tests. Samples of different types of soil were taken from
different stations, chiefly near Cold Spring Harbor, and were the
source of races of C. elegans and C. echinulata. Brazil nuts fur-
nished both C. bertholletiae and C. echinulata, as well as the undeter-
mined species A. All the gross cultures were given a serial number
preceded by the letter JT or H. The individual nuts in these
cultures were indicated by capital letters, and the same was done
for the spots on the soil and bread cultures from which transfers
were made. In some cases more than a single transfer was made
from an individual nut, as is shown by nos. 737 and 738. Generally
more than a single race was isolated from each gross culture which
showed fruits of the fungus sought, since, as table III shows,
sexually distinct races are frequently present in the same gross
culture. Undoubtedly among our numbered races some are dupli-
cates, but duplication would probably not have been avoided if only
a single race had been taken from each purchased collection of nuts.

More races of a single species were taken from 7117 than from
any other gross culture. From this culture, however, both plus
and minus sexes were obtained, and the various races of the same
sex are far from all being duplicates, as may be seen by comparing
the records of nos. 732, 733, and 739, shown in table VII A.
Despite the facts that the opposite sexes were frequently found to
be present in the same culture and that the gross cultures were
run at a temperature favorable for sexual reproduction, no zygo-
spores of Cunninghamella in gross culture were found. Their
absence may be due to the relatively meager growth of the fungus
under the conditions in gross cultures.

The tests with the different species may be considered sepa-
rately. The individual and mean grades were assigned as already
described (10, 12). For the most part, individual contrasts were
made only once, since it seemed more profitable to obtain some-
what roughly graded records of a relatively large number of separate

200 BOTANICAL GAZETTE [OCTOBER

TABLE III
ier OF RACES OF Cunninghamella INVESTIGATED SHOWING RACE SPECIES,
WHETHER C. bertholletiae (C. berth.) C. echinulata (C. ech.), C. eas (C. cle8:), .

OR THE UNDETERMINED SPECIES C. id IN CASE OF BRAZIL NUTS, PLACE IN
NUTS WERE PURCHASED IS INDICATED.

— Species Culture no. Substratum Locality represented Plus sks Minus
179..| C. berth. Hr E | Brazil nuts | Huntington, N.Y. SOG Store
180..| C. berth. Hr B razil nuts Prensgron Ney be ota ane
St Au Hz C | Brazil nuts Huntinetan ola Beg 2 a See, Place
so, A. Hi E Huts.) Huitington, N.Y. hens ees: x
183..| C. berth. Hr B } Brazil nuts ingto Ve Pas pe tery x
184:.) CoA. Hi G note -| Mutingwon, Ney 1. sa, x
185..| C. berth. Hr A | Brazil nuts Huntington; Neo ol 4. ea x
186..| C, berth. Hi D | Brazil nuts MNUINPCON IN Te cag ede ness 3
1470 CA. Hz C | Brazil nuts | Huntington, N.Y. ot. Suid x
188..| C. A. H2 Brazil nuts ti Neve uk ey x
189..| C. berth. H2 B ) Brazil nuts . | Huntington, NY) |... ..)...5¢ x
tgo..| C. A, H2 B | Brazil Huntington, N.Y > ea nee open
ror..| C. A. H2 C | Brazil nuts | Huntington, N.Y. = aay Bae ee
192..| C. berth. Hz -C.| Brevi nate” {| Huntington, N.Y) 1... 2.40... x
r93¥.1 C. A. H2 E | Brazil nuts un Flin a Rive ca ht ake
$05.51 Co WS Te ast ec, ee, “Centralstelle,”

Holand cies i er a eee x
214..| C. berth. | Tr2 C | Brazilnuts | New York City |.....|..... :
ats..| C, berth. | Teg ¥ | Bravii nots. | New York City lec a ea
216..| C. berth T27 razil nutes |: Huntington NY. ei i en os x
217..| C. berth. | T38 A | Brazil nuts Oyster Bay, N.Y She
218..| C. berth T38 D | Brazilnuts | Oyster Bay, N.Y rsa (eae ds LAR
219..| C. berth T38 E facil nuts . | Oyster Bay, N.Vo t.s. e. = =
220..| C..berth T39 A Hits) Oyster Bay Noy Tse ta cc +
221..| C. berth 130-8 razil nuts Oyster Bay, Ne of x
aaz..|.C. berth. | T39 D | Brazilnuts {| Oyster Bay, N.Y. [.....|...-- x
223..) C. berth T40 A | Brazilnuts | Oyster Bay, N.Y. |...../..... x
a24..1, CA, T4o D | Brazil nuts | Oyster Bay, N.Y. |.....|....-. x
926..| CA, T4o B ravi nuts «| Oyster Bay, N.Y fs. x
226..} C. berth 40 Brazil nuts | Oyster Bay, N.Y. j.w...).... x
227..| ©. berth. T4o E il nuts Oyster Bay, N. Ses hee
228..| C. berth. | T48 A | Brazil nuts PRCRSVile Io es >
229.4 Cech. Tiz# G | Brazil nuts New York City ee Pe eee eye
232..| C. berth. Tso F | Paradise nuts; New York City =|.....|..... x
233..| C. berth. | Ts1r A yaail nuts. | New York City 4.5...1.<... x
234..) C. berth. | Ts51r B | Brazilnuts | New York City ee ALANS BIRR
245..| C. A. ey razil nuts | New York City Be ras eae:
236,.| ©, ech. T51 H| Brazilnuts | New York City cae Sac Rr
237..| C. berth. | Ts52 A | Brazilnuts | New York City MAS Beco x
238..} C. ech. Ts52 C | Brazil nuts | New York City aa Pr A a
230.1 CA. T52 D | Brazilnuts | New York City j|.....]..... x
240..| C. berth: | Ts3 B razil nuts | Worcester, Mass. © |.....)...:. x
a4u..1 C, berth. | Des € razil nuts | Worcester, Mass. |.....|....: x
242..| ©. A. T53 D | Brazil nut Worcester, Mass. pe Tare EAs
243..| C. berth. | Ts54 A} Brazilnuts | Washington, D.C. |.....|.. aioe
244..| C. berth. | Ts54 B | Brazil nuts eshineton, DG. 4... ..ie x
245-.{ C. berth. | Ts At 3 i Brookiva, N.Y fore. ch, x

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 201
TABLE I1I—Continued
— Species Culture no.| Substratum Locality represented Plus aoe Minus
246..| C. berth Ts5 B | Brazil nuts Wookiyn, MY Geb x
247..| C. berth Tss F | Brazil nuts qoukiyn, NV to. 5 ee agar
248..| C, ech. T66 A | Brazil nuts New York City 7 Aa iit eat Rane ia
249..| C. berth T66 B | Brazil nuts lew York City’ {e534 + i Rae ai
250..} C. ech. T66 C | Brazil nuts jew Yorke City tela x
252..| C. berth T67 A | Brazil nuts jew York City te ee Sh oe x
253..| C. berth T67 C srazil nuts lew NOrk City odes hc m3
254..| C. berth T68 A | Brazil nuts WOOK vn NY. ee Pe *
255..| C. ech. T68 A | Brazil nut rooklyn, N.Y. yee basher Pasa
256..| C. A. T68 B | Brazil n dna an Me OO are RO To ee x
267,.1 °C. A, T68 C srazil nuts YOORIVN ONY soe ig. he x
258..| C. berth T68 D razil nuts POOKIVED DL ie a x
256. 00. A. T68 E razil nuts rooklyn, N.Y. Re eo ae
260..1 C. A. T68 E zil nuts rooklyn, N.Y. 2, eget ange et
261..| C. A, Los razil nuts ew York City 2 a Cia aed Brret
262..) C. berth T73 8B reel nuts 4 New York City oi fo x
265..| C. ech. T44 B | So Id Spring Harbor |.....}..... <
266..| C. berth Tso F | Paradise nuts} New York City (|.....|..... x
267...) C.A. T52 D| Brazil nuts | New York City Si evees
268..| C. berth. | Ts52 D | Brazil nuts | New York City Bae free es Cee
260:./' C.A:. T68 C | Brazil nu TOOKIVI: INV oo diet x
a70. 1 COA, T27 B razil nuts hintington, Noy. boa x
271..| ‘C. berth T38 B razil nuts yster Bay, N.Y ee ae
e724 ©. A. T68 D | Brazil nuts POOKIE ee sa x
273..| C. A. T73 C | Brazil nuts | New York City + ls PENS Fe et
274..| C. berth 73 © razil nuts OW Pore OY cet, x
275..| C. berth T74 E razil nuts OW Tire Cy dl x
372..| C. berth T76 B razil nuts OW VOTE CIV os x
373-.| C. berth 176°C razil nuts OW VOR Cy ak 5S aa
446..) C. berth fo razil nuts MOORE NY Oo Te *
447..| C. berth T74 C zil nuts ew VOre CR sas x
448..| C. berth T75 A | Brazil nuts low York (My 2 diag ot, x
449..| C, bert T79 razil nuts OW TOUR NE as x
450..| C. berth T80 B razil nuts lew York ONY = fooc.. © a
451..| C. berth T80 E razil nuts ew: York City ee x
452..| C. berth. | T8r B razil nuts rookiyn, NOY.) di... oe Cee ae
453-.| C. berth. | T8r E razil nuts POORIVI, ON ee PT a 4 x
454..| C. berth To96 A | Brazil nuts Oe NTR ae Brees Vata ie x
455-.| C. A. To96 E | Brazil nuts CON dig as x
456..| C. berth. | To96 C | Brazil nuts torrs, Conn ee a re
457..| C. berth. | To7 B | Brazilnuts | Amsterdam,N.Y. |.....|..... x
458..| C. berth. | Too A | Brazil pn i ee x
459..| C. berth Too D | Brazil nuts Amsterdam, Nov. 4.66 ~
460..| C. berth Too C razil nuts Meastetdam NYS i ih x
461..| C. berth. | Troo A razil nuts Amsterdam, N.Y. his pesk x
462..| C. berth. | Tror A razil nuts Amsterdam, N.Y.) if .. x
463..| C. bert Tior B i mits.) Amsterdam, N.Y. 2 1, -.5. 1.5... x
464..| C. berth. | Tror C razil nuts Amsterdam, N.Y. ae ee wre
465..| C. berth To8 razil nuts | Amsterdam, N.Y. 5 eee Saar) Pee
466..| C. eleg T29 D | Soil Cold Spring Harbor | x |.....J...-.
467..| C. eleg T36 B | Soil Cold Spring Harbor }..... re Se
468../ C. eleg T36 C | Soil Cold Spring ae b : ee ae FOLe x
469..| C. eleg T44 D } Soil Cold Spring ey Cees Pe
47° eleg Ts8 D | Soil Cold Spring Harbor yee Bees Pe

202 BOTANICAL GAZETTE . [OCTOBER
TABLE I11—Continued
_— Species Culture no. Substratum Locality represented Plus pag Minus
Ayi-:| C. elec. T6o0 Te) Cold Spring Harbor Kes eee ee
472..| C. eleg. T6o D | So Cold Spring Harbor |.....]..... x
473-.| C. eleg. T6o0 E |} So Cold Spring Harbor pity peor reg
474..| C. eleg. Tor. D j5So0 Cold Spring Harbor x hos ane
475-.| C. eleg. EG: Col So Cold Spring Harbor |.....|..... x
476..| C. eleg. T6r-E So Cold Spring Harbor |.....|..... x
477-.| C. eleg. T61 G} So Cold Spring Harbor |.....|..... x
478..| C. eleg. T62 A | So Cold Spring Harbor |.....|..... x
479..| C, eleg. T62 A | So Cold Spring Harbor |.....|..... x
480..} C. eleg. T63 A | So Cold Spring Harbor |.....|..... x
481..! C. eleg. T64 D | So Cold Spring Harbor ies alae
482..| C. eleg. T64 ) Cold Spring Harbor: } 6x .}.1-..1)-4.2
483..| C. eleg. T64 E | So Cold Spring Harbor |.....|..... x
484..| C. eleg. T64 F | So Cold Spring Harbo ed SOR a
485..| C. eleg. Loe © te) Cold Spring Harbor x ieee
486..| C. eleg. T65 A | So Cold Spring Harbor |.....|..... x
487..| C. eleg. T84 A | So Cold Spring Harbor ee pee
488..| C. eleg. T84 B ) Cold Spring Harbor }.....]..... *
489..| C. eleg. T84 ) Cold Spring Harbor |.....|..... x
490..| C, eleg. T85 B | So Coid Spring Harbor]. 4.51.35 x
491..| C. eleg. T8s D | So Cold Spring Harbor |}.....]..... x
492..| C. eleg. T8s5 E | So Cold Spring Harbor nag Bare Fever i
493-.| C. eleg. T86 A | So Cold Spring Harbor Den Pian ge uigue re
494..| C. eleg. 1386 © |:So Cold Spring Harbor 5 ates oper Cate
495-.| C. eleg. T86 E | So Cold Spring Harbo Roe ee a
496..| C. eleg. T86 F | So Cold Spring Harbor} x) jis. es
497-.| C. eleg. T86 0 Cold Spring Harbor Sock eviews
498..| C. eleg. T87 0 Cold Spring Harbor b dit Cac me rer
499-.| C. eleg. T87 F | So Cold Spring Harbor pe ee Pe
500..| C. eleg. T89q 0 Cold Spring Harbor Mi tors be es
5or..| C. eleg. T89 B | So Cold Spring Harbor Bel
502..| C. eleg. 189 ©‘) So Cold Spring Harbor ae Picea Beet
503..| C. eleg. To2 B |} So Cold Sprin rbor 5 tee Be eee Pe
504..| C. eleg. To2 D | So Cold Sprin rbor Sle ee ae
505..| C. eleg. To2 D | So Cold Spring Harbor Re wee, bees
506..| C. eleg. To2z E | So Cold Spring Harbor |.....|..... x
507..| C. eleg. To2 G | So Cold Spring Harbor |.....|..... 4
508,.| C_ A, Ts52 srazil nuts Ne ork City be eae eee
$10..1 een. 1. La tory
ection | Washington, D.C. |.....]..... x
rr.) Cok T73 D | Brazil nuts Mew Vor ty 6 x
pra tA, T75 A il nu New York City SOUS ee
33..) CoA. T75 B | Brazil nuts | New York City |.....|..... x
ra.) UA: 775 ©) Braail nuts | New York City |.....[..... x
rc. CLA. T75 F | Brazil nuts | New York City oe.
16.) CoA, T76 A | Brazil nuts. | New York City |.....|..... x
£7... C. A; T76 D iinute | New Yoru City . f.... bus. x
8.1 C. A; T76 E } Brazil nuts mew Vorwe City. 1h x
16..) CA. T7o B real nits | Mew You City = 1... 4, x
ao,.| C. A, T79 F | Brazilnuts | New York City |.....|..... x
war.t OA, T80 A | Brazil nuts | New York City Rosh cages
§22., CA. T8z C | Brazil nuts | Brooklyn, N.Y > ee Penn Bee
523.) €. A; T8: G | Brazilnuts | Brooklyn,N.Y. |.....|..... x
g24..j C. A. T96 nut torrs, Conn. be Senne) Bis

BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA

1921] 203
TABLE IlI—Continued

— Species Culture no. Substratum Locality represented Plus — Minus
S25. C. ech To8 C | Brazil nuts | Amsterdam, N.Y. ss Faas aero
526..|-C. ech. ‘Loo A: |. Braziinuts . | Amsterdam N:V. 0 12 le x
527.) CC. ech, To7 A | Brazil nuts Amsterdam, N.Y us
528..| C. ech. Too E razil nuts | Amsterdam, N.Y ON eases
529..| C. ech. Too E rail nuts | Amsterdam oN Vo Fee *
718..1°C berth..| Lrir razil nuts Otway, Dees cos a a x
Fiore Cuberth| “E112: razil nuts Parkersburg (W,Vao jin clisos. hs
yao. Cy berth, | firs: € razilnuts | Louisville, Ky. —s_[..... Sy
721..| C. berth. | Tr14 A razil nuts Pea Ad. a is x
722..| C. berth. | T114 D razil nuts RERUN BN 5 Ee pic te cas x
723.;) Co Derth. [EIS A razil nuts Pickory, NC te. nee Oe
7242.1 ©, berth: 4 F115 B razil nuts Hickory, NoCioe os ee ee ok x
725..| G. berth, |; Tits: B razil nuts Bickory, NG aba ty x
726,.| C. berth. | Trrs F tam wane. | Mackory, Bt x
727..| C. berth. | Tz16 B i] nuts Byoxvile, Tent eo) oe x
925.) Coberth, ) P16. C razil nuts Knoxville, Tenn. [60 och es, x
729..| C. berth. | T116 G razil nuts Knoxville, Venn 26 7c oy, x
739..| C. berth. | Tz17 B | Brazil nut Byorville, Tenn i *
Jarl. berth: ||- Fir? B razil nuts Kuoaville, Tene yi. x
932..1'C. bert T1117 B il nuts Knoxville; Tenn. 2) 2 6y2) > a.
733+.) G. berth, | Tr17 B razil nuts Knoxville. Tenn od oi x
734-.| C. berth. | Trr7 C razil nuts Kroxvilte, “Leni oe x
735--| C. berth. | T11r7 C razil nuts Knoxville Tenney l. . 1o . x
736..| C. berth. | T1r7 D razil nuts vie se x
737..| C. bert E1r7 D H nuts) | Buoxvine, Fenn. oot x
738..| C. berth. | Tx17 D razil nuts oxville, Tenn > ned Bs BR
739--| C. berth. | Trr7 E razil nuts Mnovville Tenn oe ee x
740..| C. berth. | Tx18 A | Brazil nuts He, Leni le x
741..| C. bert T118 D razil nuts Knoxville, Fenn. i =
7420:-C. A, TritA razil nuts Norwave me. i x
fag. Ay rit B razil nuts WNOrway, MG as x
FAA TC. AS Trt € razil nuts Norway; Me. ° 63 ioe. x
745... CA, Trim G razil nuts OIWay, Mel ee. x fo.)
747..| C. ech. Ti13 B ilnuts | Louisville, Ky ye AE Rae
748..| C. A. Tr13 B | Brazil nu isville hee Rss oe
749..| C.A., T113 B | Brazil nuts | Louisville, Ky peat tee
759..| C. ech. Tris C il nuts MEI 8 hae x
oi. tA. T113 D |} Brazil nuts MOVIE, Ne oo te lec. 3
752.3) U. A. Lii3 Do} 4 iinuts {| Louisville, Ky ef ae
Tsact bo A. Tr16 A srazil nuts Knoxville: Team 30 och os x
1581 CA. T116 D i oxville, Tenn. .3 aa ee
755-1. C. A: a0 D razil nuts Knoxville, Tenn. 5 ae Pa ae) Wen ena
756..| C. ech. T116 E | Brazil nuts Rroxvue, ben x
757.41 CUA, T116 E razil nuts oxville, 2 eg) eatin cy Baer x
758.14 C A, 116 H| Brazil nuts | Knoxville, Tenn. |.....[..... x
750.1 CA: 118 D | Brazil nuts Knoxville, Tenn Ga ee
779..| C. berth. | Trrs D | Brazil nuts | Hickory, N.C. ee ae a
weg Ce be ok Laboratory

culture Cambridge, Mass. eo ee ee.
Pee Cech fe ee Laboratory

culture Cambridge, Mass:. jf. 6.2. .4...-. x

204 BOTANICAL GAZETTE |ocTOBER

contrasts than to attempt to secure more accurate records by
averaging the grades of a relatively few contrasts which had been
several times repeated. If any of the cultures had become infected
or in any other way appeared abnormal, the contrasts of course
were repeated. In a few cases, especially in the earlier contrasts
with C. bertholletiae, zygospores were found where, on the basis of a
strict sexual dimorphism, they would not be expected. A repetition
of these contrasts under improved technique gave the results incor-
porated in table VILA, and indicated that their earlier aberrant
behavior was due to infection with the opposite sexes of the same
species. All contrasts with species of Cunninghamella have been
grown in the incubating oven at 24°-27°C
CUNNINGHAMELLA ELEGANS

Table IV shows the tests with C. elegans. Twelve races were
used as testers, and in all 426 contrast combinations were made
with the total forty-two races. Of these, twenty-five were plus,
sixteen were minus, and one, on account of its failure to show
reactions in any of the combinations tested, has provisionally been
listed as a neutral.

CUNNINGHAMELLA ECHINULATA

Table V shows the tests with C. echinulata. All the 153 possible
contrast combinations were made with the total eighteen races.
Of these, ten were plus, eight were minus, and none failed to show
a sexual reaction in at least two contrast combinations. Since no
reactions occurred when races with like sign were contrasted
together, only the contrasts between plus and minus races are
represented in the table.

CUNNINGHAMELLA A

Table VI shows the tests with the undetermined species of
Cunninghamella provisionally termed Cunninghamella A, It is a
form intermediate in appearance between C. bertholletiae and C.
echinulata, and was at first confused with them. In tube cultures
it approaches more nearly the habit and color of C. echinulata.
From this species, however, it may readily be distinguished micro-
scopically, especially by the lack of conspicuous echinulations on
the conidia. The form, however, needs a more careful study than

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 205
TABLE IV

FORMATION IN DIFFERENT COMBINATIONS INDICATED BY LETTERS TO 1);
ABSENCE OF ZYGOSPORES INDICATED BY U; GRADES ASSIGNED TO INDIVIDUAL
RACES ARE MEANS OF THEIR REACTIONS WITH TESTERS OF OPPOSITE SEX; NO. 230
NUTRIENT USED, CONSISTING OF 2 PER CENT AGAR, 2 PER CENT DRY MALT EXTRACT,
2 PER CENT DEXTROSE, AND 0.1 PER CENT MEAT PEPTONE,

Minus testers Plus testers
Grade Races
475 | 472 | 468 | 478 | 507 | 406 | 466 | 474 | 469 | 470 | 471 | 473
Plus races
2.60 | 400 re. Bre Te | ee To La oP TO PO
POOH ase eee oe ATS BVO TD 10 7ro 7 O10 FO 1010
2 AO PAST le hie ce BAA tB tO TD TO 107070 10°|070
SAO SOR es CrB eB ya Bor OD OO: 0710. 0
FBO ARES or So os Boer Dp ey BO OO Orr Oot oO
ri ea ee” UN at BS AGA EOC 1D rere Of Oro 1 OO
PERO AOA ee ALB oa DDO 10-78 oO 0.) Oo.
2.20 1800 ky Bon Pe COP OO Ow OO 20 Fo
290 4 Sg ee or, Bib rc. DC 10-0 ee Oo: TG
BOO MOO eS oS we Crh Cus OOO Ose PO 4 O47 oO
BOO} BOO is Cues BoC Bee: Ovo ee te 10.41 oO
© OOP 802 es ay oa Cre re tt BR to ote PO LO Too
TRO ar CPB Ba DTU ee role oO
BBO 469s 6 obs Sy Cyc PevulC fps OOo 1 oO: ;Oo1e to
EiOO Taree CtC rh Dpto O.10 1 Or0 |. Oo 18
POG Abe ee Pak BLiLCopirD ype 0 10 1040250 10
SOG 1 B08 vie en: CLC pee ye e704 OO Or 6
TE AO AOR or Dro te Le eo te OO O10 10.1 O
PA ae DeDiD TOre +O Oo -O°Tro ro 18h...
1.40 | 481. CC oC iD OO Te Oo O18 POT oO
TAO | ASS ey ClCo reap to 610,076 10 oO 190
AO P MGs Cro tpa ea pro Tre too Te 70 6
1.40 | 495. Coro pt pp OO pot oO oO
E40 feos oa CLiprlrprtpi Cc ro ro 1o +o O46. ob
ESOOs BOE Oey OO] Crp tO bo 1070 10°) 0 4.0
Neutral races
OOS ft AG Sa a O10 (0/6/00 1.030 1010 10716
Minus races
2.70 1800.6 O1O FO LO 1O re CBU BIS Tee
ON? aye 2 ooo eo, Ol. Ono vo fR eC 1A TB COLD
BUG eIOc ges OO £07010 -B ETB Te 1c Fre LD
PES7 FP AOO ee oy OO O70 tO TR BCC rA TBD
SAS PAIS OSG kek tO O 10 1D BAR A LC LC Le.
ig A va ee ee Oro Oro OTC rR 1 CAG rTCa kB Fe
220 ABQ. ae, OO +G7 CO TRB YY CLC Pe Ure Te
2.84 F408. Oro hi AO TO BrP Cc CB Ye Dp
2.44 f 456. 6055 2, ProTrO TO rO4aS tk Bec Tce
216 t 4000 O10 7070/0 78 (0 7C71C pe re 1c
1.501 Ae a. Orolo |. [OTB CiD ITB Dav iCc
eet aes 8 COTO Oro Tro TA Te TD PC pte Te
Roe MO es: O20 10 +610 1/C 1rC 7 C lC ep Pe
TPE ee oa O1O7O (O;G1 RIC Tre CO rc ED
TOR) Rie oe O1,O7;,0 10 J2.71C 1B 10 10 -o oO 1c
Oph O79 oe, O1O ro 1Gto1ro 1D DYDD Ep To
Grades (all combina-
MOMS) 6|2.24|2.12|1.44|/1.12|2.69|2.25/2.12|2.06|/1.94/1.94|1.31

206 BOTANICAL GAZETTE [OCTOBER

it has received before it can justly be described as a distinct species.
The manner in which the races reacted in combinations first
suggested that another species was included in the collections, and
a later inspection and microscopic examination showed that species

TABLE V

SUMMARY OF TESTS OF Cunninghamella echinulata: RELATIVE STRENGTH OF ZYGOSPORE
TION IN DIFFERENT COMBINATIONS INDICATED BY LETTERS A TO D

ABSENCE OF ZYGOSPORES INDICATED BY O; GRADES ASSIGNED TO INDIVIDUAL
RACES ARE MEANS OF THEIR REACTIONS WITH TESTERS OF OPPOSITE SEX; CON-
TRASTS BETWEEN RACES OF SAME SEX MADE BUT NOT REPRESENTED; IN ALL
CASES THEY FAILED TO PRODUCE ZYGOSPORES; NO. 362 NUTRIENT USED, CON-
SISTING OF 2 PER CENT AGAR, 2 PER CENT WHEY POWDER, AND I PER CENT

Grade

2.50") 3295 1 3587) 2 04 | 2.03 | 280 1285 1.2025) bits: [0.50

Grade Minus races
Plus races

747 885 527 229 525 238 236 255 248 528
2.70 | 886. B B B B B C B B KS Cc
2.90 4 86865. oles: C c C C B c Cc B B C
4.00 | Yeo. Ce a, C B B A O B B D D oO
¥700 | 516.4. 3- 2 t B B B C c Be O D O O
Psa 690-0 6. B 2 C C 1@) Cc e 0 C O
r.10 | §26. it B oO O B O O & D O
Be | ee LS © C oO O D Os 0 O O
0.50 | 250. B O O O Cc O O O O O

A could be distinguished from the other species. Six races were
used as testers, and in all 297 contrast combinations were made
with the total fifty-three races. Of these, twenty-two were plus,
twenty-nine were minus, and two, on account of their failure to
show reactions in any of the combinations tested, were listed as
neutrals. Imperfect sexual reactions, indicated by small letters in
table VI, will be discussed under the following species.

CUNNINGHAMELLA BERTHOLLETIAE
Table VII A shows the tests with C. bertholletiae. Fifteen races
were used as testers, and in all 12r5 combinations were made with
the total eighty-nine races. Of these, twelve were plus, sixty-nine
were minus, and eight, on account of their failure to show reactions

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA

TABLE VI

207

SUMMARY OF TESTS OF Cunninghamella A: RELATIVE STRENGTH OF ZYGOSPORE FORMA

STRENGT.

LETTERS 4

SEXUAL REACTIONS INDICATED BY O; GRADES ASSIGNED TO INDIVIDUAL RACES ARE

HEIR REACT
USED, CONSISTING OF 2 PER CENT

CENT DEXTROSE.

IONS WITH TESTERS OF OPPOSITE SEX; NO. 362 NUTRIENT
AGAR, 2 PER CENT WHEY PO

WDER, AND I PER

Minus testers Plus testers

Grade Races

269 182 257 515 242 181

Plus races
BOO RES ee ea A A OE Boao 8) Oo
SOU ee a A A B 8 2B Saker aus O
Ge Bien) a eee B B A O 2 es ar pean
BO F IOt. Soo oes B B B O O O
BcOP VEO iy cme CG B B O O O
ore OF C oe B O O O
DAR eee rc ey C B C O O O
2. BO a ee: & Cc oe O O O
2. PRE ea ee st c Cc . O O O
PE 258 a, C i D O O O
Poe MSE ee oe Y C us D O O 0
Or SOS es ee C D C O O oO
EGF) ber oe oe, D C am O O O
POP de oS D Cc iB O oO O
PSs 1 906. case fo ee, & D D O O O
> ue ar cg ag coe en c D D O O O
Pees 1 S24 eee cl D C D O oO O
EO 100. on a D D D O O O
FP Oe Sie oe D oO C O O O
O07). 820 32 6 oc DD, D O O O O
Se Ise a ca D O O O O O
Oss 10s D oO O O O O
Neutral races
001 JAR oe a O O O O O oO
O00: fF ona eS O oO O O O O
Minus races

2.09 1 Ye Oo 4 oO A A B
Ra ea, OR ie en ey yn O Oot. A B A
3:07 (20000 oe ae O O A A B
SR Sa SIF ee oO O O A b b
SUS8 1 S88 O O Oo A b b
600 (944 Ge O O O A C B
BOO FASS ee eos Oo O O A = B
PAP eA ic O O O A D Cc
238 O66 es oO O O B Cc 3
POT ase oo O oO O B D D
1.07.) 288, oO O 0 d b D
R557 Sie ye ae O O O B O D
PO ew O O O B 0 0
COO 9et O Oo O b O oO
Ara eee ene O O 6) Cc 0 O
Ot oie 6 O O O Cc 0 0

208 BOTANICAL GAZETTE [OCTOBER

TABLE VI—Continued

Minus testers Plus testers

Grade Races

269 a0 257 515 242 181

Minus races

Po Da i aor dee lpn ie rg O O O Cc O O
O.67 brit. oa O O O C O Oo
O67 81655 a O O O C O oO
O07 PSth es O O O . O O
ragty sy Rl Gh (oie mele eyes oO oO O c O oO
O69} 9Ae oO O O c oO O
OF) Tha coe eee O O O Cc oO oO
OOF teeter yee, O O oO 5 oO oO
OOF P7Ges ee yt O oO oO c O O
O07) O4F 2. 5. O oO O c O O
O07 Set ec oO 0 O c O O
O55 | Soh es. oO oO oO D O O
Oss PelOe ee. O oO O O O d
Grades (all combinations) .} 1.91 1.86 1.82 2.50 0.07 163

in any of the combinations tested, have been provisionally listed
as neutral.

C. bertholletiae seems to differ from the other species of Cunning-
hamella investigated except species A, and in fact from all the
other mucors which have been studied in the same manner, in that
between certain races imperfect sexual reactions have been found
which do not lead to zygospore formation. It is possible that
such reactions may occur more frequently than is realized. In
contrasting the first few. testers of a given species, the practice has
been to look for imperfect reactions at an early stage of develop-
ment, and, if none are found, to examine the culture dishes in later
series only at the end of the growth period when imperfect reactions
would not readily be recognized. It is thus possible that some of
the zero records for the contrasts of species A in table VI would be
replaced by grades of imperfect sexual reaction if they had all
been retested and inspected at an early growth period. Imper-
fect reactions are graded in the tables by small letters instead of
by the capitals used for zygospore formation. The reaction might
readily be confused with the early stages of zygospore formation
or the final stages of ‘‘imperfect hybridization.” Imperfect
hybridization has heretofore been found to occur only between the
opposite sexes of different species. When dealing with races of

SuMM.

RELATIVE ST.

21]

BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA

TH IN IMPE

TABLE VII
ARY OF TESTS OF Cunninghamella bertholletiae:

RFECT SEXUAL

209

RELATIVE STRENGTH OF ZYGOSPORE
D,

DICATED BY SMALL

LETTERS

a To d; PRODUCTION OF PARTHENOSPORES (a-ZYGOSPORES) INDICATED BY CAPITAL LETTER

TERISK; ABSENCE OF OBS

ERVED SEXUAL REACT

ION INDICATED

By O;

OF THEIR SEXUAL REACTIONS WITH
TESTERS OF OPPOSITE SEX; NO. 230 NUTRIENT USED, CONSISTING OF 2 PER CENT AGAR,

2 PER CENT DRY MALT EXTRACT, 2 PER CENT DEXTROSE, AND 0.I PER CENT MEAT
PEPTONE
A. INTRASPECIFIC REACTIONS Fo Magara
Grape} Races Minus testers ress Plus testers ‘Minus testers Roden
266 oi OY 8 o 34 aij [424i 63 O4 4 i495 88 6 5f5
Plus races
Soo pre AUBLBLBRUBTS | €C).01 017100 Ono Ol dite Ch OT:
2.71 | 234.. Ibibbe?= Bi cl bEb1 Ol OFO! OF.0Ol Ol Obi dtc oro
2.71 | 268. LBIAPB? Blere be, OVOl Oro OO LO ec Phe OL.
eRe AOS) Cr bi Bi bie rat CrotOv OL ororgeroy or... DO: 3:
ea tT 287. os Breeelt Brel bic? Orolo: OOO Ore). GC OL...
BAe AGA CEL: By; Bi} BIB ¢ tdi Cl).0, 0101 OO Ot Ole bh ab OR:
iat ae Bi Ci Bl Al Di OO}. ci 010! 0; O10; O10) Ol... POR...
ioe b e90s ee ble Did t_biecrol-0O1 0) O10! 6] OOO... ICW OL;
TAs AG oe CEepLec LDL dt Orel O| GLOLG) Ort O13 1 Oi kt Ol:
b96 eis Dicer oT CrerolyO1rorero oreo OL... 2 error...
£220 | O4te ss cre€retdre tore: 07 ei 0) O01 O01 0] OF. t FCW OT O
Oa eo. DOLD OL O01 Dror Or GrGl010. 01 OL OL a bor
Neutral races ‘
O00 Ore oe OF Ororororo; ol Ore oro. oreo! OL. OL:
B06) 247 oo, OF 01010! OT Gi OF 0] G1 01 G6 Ot 0] Ol de Ol:
O08 1 eig.. 3 lc. OFro; 6} Of 0; 010) Ol 00 OH 8 Ot OL 1 OL:
0,00 | 3727.5 ,... OF O10! OFO} OF CO! O} 0} OF Oj] O01 O} ORs aOR.
0,00 | 450.555: 0! 01 OF 0) O10; OLG! 0} OF 01-010) OF, Ol. ie. Lok...
9.00 | 454....... OO; 01 6G] OF 0} 610! 0 FOC OL Ore. CG. Oy... 1. Ol..:
O00.) 990.607 35 OrOoTrol1o;ororod! O10) Grol GG) Gi OL Ord. orOon..
00.1 Faq ioc.. 5) O} O} O} Of] O} O| O} O| O| O} Of; O} O} OF O}. OL:
Minus races
$.00 1939 See O10 OO! 0 O10| O10: ALAL BC) Biel... Or biC
$200. 1 G06 |) OL010-0101 601 OFO! ALB Bi bt BI C).0l Offa dh.
S00) 2742 rs GO; Ol 0} 0; 6} OF 01 Ol OF BB Bi bi Al ci Gi el.
3:00 |) F200. 225 3 O'; 0101 01 01 O10) GO] GOLA! ALATLOLAI cl..4..:)OPer..
S00 7407... O}..:) O01 O10} O} 0} 0; Bi Cj] Albi Bi bi CO} OL. |...
oe ea 7 at es GO} 0; 0} 0):01-0101 01 OF Al BI Bic) Bist hala,
907 | are cy O10! o}.. 10) OF GCG} OF Ol] BI Bi Bib) BDO, Ole...
07 t 28000 os. O| O01 G6! 6101.6; GLO Bi Bi Bic! Bleek
2.09:1 362.05 207, 0) 01-01 0} 01 6G! 01 O01 At Bi Bib} Bi O..4 4 aL.
OOF | £60, 62 ees OLO; + OLOLOro! OO} Ol BiB Si ¢i Bie} O11 CLek:.
2.50 | 93st. 25, O} O} O| O| O| CO} O| O| O} B/ BI B{| C| B] dj...j...]...] a [D*
2.50 |) 9960005. 3 | GOO: 0} OF 0101 OF0) Al Al BI Ol Cl €4..4:.4..47 81...
B40.) Abeo oo, 0101.6) 0! O60! 01016. Ci Cl Ci bi Bleh. abe.
at? | 2G 016! 6161 0) 0-61 OF 01 Bi DIC! a7 BO Ek.
2:00} 180... . 4 OOo: 0! G1 01... OF Ol Cl e€ic thi Ci ad} OF.) OFOL.
2.00 | 183....... O| 0] O| O|...; 0} 0] O| O] bj c}/ c¢}|c]{ec¢}]d{O; O; Oj bi..

[OCTOBER

BOTANICAL GAZETTE

TABLE VII—Continued

pies gers lee a eee se aa eee i gee gee A eg A Ge Seem cine Bee Mae ebas Gabe cage yomer fete wate SC 1 cheng poet mo oe yak ae So ace re a eee ge aera Ra ne

en Sl ies we De a ee ee

by | eh a] woaoe vo eleme eee Me eseoce... 5606s ee
Oe eee ee a
a: ieee ee eee
B18) Ott ee a

% SOS900000 LOO 00 vOOOOOOOTOOOOD OO COO OOOUCDOOOOCOOUDOO

i é TOO vOOuMOOOAROCO yBOOOOOOLVO99O99909990090000 a vad vOVOO

: S| BPHovvv v0 vO vpvyvyd ye vuvOvOOOOvsO 0000000 e0000000000

3 S PVYVHYUYVHYVHVHHVHVHOVHOTVL VEOH YVYHOVVLVVLVLLVLVLVYHVLOOOOOvOOO0O0 v0

z 8 . DPvoQvovvvvvvv0vv0v0Ovvvvvve9dvv vv vv VV V0 v Vdd vOOOOO000Os
g P| O2OOVECvs 2800 TH oAvreoMeoMoveovuUUUUUUD ODUM UUM LDLONM
s #8 be ojelelelelelolelelolelelelolelele) eo) elolelelelelelolelele)ole)elele)e)olelelelelelelelol=)
5 Ee: 2 099999999999990009009090000000009009000000900000000
5 & eolelelelelolelelolelelelojeelelee)eeelelelelelelolelelelelelelololololelelelelelelelolo)
i = Rojelololelelelolelelelolelsjlolololololololelelelelalalolelelelolelelolelelelelelelelolelelo|
i Ph eseolejlejejojelelalajlelelelelelelojejlelelelejolelalelelelelelelole)olololelolelelelolelo\>)
“ 2 SOOSOSOSOSOOSOOSOO SSO OOOO S 9999 0O9090909009900000000000

E ra BO OOOO OOS OOOO ROO OS COORD OO OOOO OO0oe

3 SCOSSSOSSSSSOSSS SSS SSO Sooo ooo oOo CoCo oOOOCOOCOC0000000

8 elelelelelelelelelelolelololele) a) eee) eleele)e)e)e)e) ele) e1e)ele)a)elelelelelelelelelelele)
Wee a

: ee eee.

° SIS TSE TS SSSS OSS SPSS PESSE SASSI TIS TS SS SSSR SSIs Sy
SSSLILAASSSIVSSEKHHEHH LS 88s BLLHHHSHSHSSSSSS LLIB

GRADE

paneer Seth Na eM yea yim, am gis a aoe ye eda Ne Ms Serge eg es a Ry a ae eee ine Sar pepe ee are rates yea etn ae ae nae ce ee ee re eee

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 211

‘ TABLE VIIl—Continued

o.60:90 00

A. INTRASPECIFIC REACTIONS daa atay
GRADE RACES Minus testers pooping Plus testers Minus testers Dob net
266 1457 1459 |213 |183 |241 [18 5 145 7 |227 |268 |234 |464 |456 |188 lass |260 |ror |515
Minus races
od ay ets eee 01-010) OFOLO1. OL 0OLObe Ol OL OLOT OO; c
al ik 7. Oat GO| OG rOrOLOLOVOL@Ord] OFOLoTrda-O7.. c
cs ay Die ee ea O; OPO; OF OF OPO) OVore 1010; 01T0Lro}:. c
cael = Wen ce O| O} O} O} OF O} O} O} O} d}| O}| O| O} dj O}.. a
cc ae Br ce eke ages QO} 0; OF OO] OO] CO] GO; OC] 07 OF 0] Oi cc EOT.. O
Sy (all iy © Con O} OFO} 07 O10 0} Gl -d70] 01 01 DI Ol... c
Grades (all com} %/3/2/8/S/5/ 3/8/18) siaislsisis
tions) egg alalalalxals ° ° adel ew |e oe °

the same species, if any reaction was initiated at all, it was carried
through to the production of zygospores, except of course for some
obviously detrimental check in environmental conditions. The
sexual process resulting in the production of zygospores may be
considered the sum of two distinct reactions; first, the formation
of opposed progametes or at most gametes; second, the dissolution
of the cross walls between the gametes and the growth of the
fusion cell into a zygospore. Only the first reaction can take place
when the plus and minus races contrasted belong to different
species.5

A number of facts indicate, however, that in the races listed
under C. bertholletiae we are dealing with a single species. The
essential uniformity of the strains in morphological appearance
speaks for specific identity, and the production of zygospores fails
to separate them into any consistent groups. A quadrangular
reaction within selected groups of four may be discerned from
table VII A. Thus the same four races shown in fig. 1 form the
following quadrangle, in which Z stands for zygospore formation,
H for imperfect sexual reaction, and O for no sexual reaction. Other
similar quadrangles may be assembled from table VIIA. The fact
that only imperfect reactions are found in certain contrasts when

True hybrids have been reported between closely related species of Mucor by
Sarto and NAGANISHI (19).

212 BOTANICAL GAZETTE [OCTOBER

zygospores would be expected does not alter the sex of the races in-
~ volved. When they take part in any sexual reactions at all, they are
consistently either plus or minus. The first reaction of the sexual
process is sufficient to indicate their sex, and gives an index of their
sexual vigor. In calculating the mean grades of sexual activity for
the different races, therefore, it has been considered fairest to give
the imperfect reactions equal weight with zygospore formation.
What are the causes which prevent oné combination in a quad-
rangular reaction from carrying the sexual process through to
completion is a question requiring further study. In certain cases,

465 plus H 457 minus
Z O Z
459 minus 4 217 plus

at least, the distance between the inoculations of opposing strains
seems to be a matter of some importance. In Circinella spinosa
it has always been necessary to inoculate the opposite sexes very
close together in order to obtain zygospores, which are not formed
beyond a few millimeters from the points of inoculation. In a few
cases a retest of an imperfect reaction between races of C. berthol-
letiae, but with inoculations close together, has shown zygospore
formation. .

Certain contrasts which were repeated with inoculations at the
usual distance apart gave different reactions from those first
obtained, as may be seen by a comparison of table VII A with
table VIII where the retest contrasts are listed. In table VIII
there is, as might be expected, a certain amount of change in
the grades assigned to the strength of the reactions. The present

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 213

interest, whoever, centers upon the grades inclosed in paren-
theses, which indicate reactions which have changed from a
perfect to an imperfect reaction as shown by the production of
stages resembling imperfect hybrids in place of zygospores. It
will be seen that there are certain unexplained irregularities in the
production of zygospores or of only imperfect reactions which
indicate that the preliminary tests have not discovered all the
factors involved. Enough has been learned, it is believed, to
indicate that some of the factors are environmental which deter-
mine whether a sexual process in this species goes through to

TABLE VII

RETESTS _ CONTRASTS BETWEEN RACES OF Cunninghamella bertholletiae: CAPITAL

RS INDICATE GRADES OF ZYGOSPORE FORMATION; SMALL LETTERS INDICATE

pri bees OF IMPERFECT SEXUAL REACTION; LETTERS INCLOSED IN PARENTHESES

SHOW CHANGE IN TYPE OF REACTION FROM ZYGOSPORE FORMATION TO IMPERFECT

REACTIONS; REACTIONS WITH ASTERISK INDICATE PRESENCE OF PARTHENO-
SPORES; NO. 230 NUTRIENT USED

Races | 266 | 729 | 732 | 457 | 737 | 213 | 450 | 731 | 219 | 180 | 241 | 232 | 460 | 718 | 74x | 721

FSG ot alt tO) ec © eel ee ee

iy totes (aR RN GR ee a C1 eas OA Bes ae

AOC ie | ee re arte Oy Oe) +

Lege A oo Deuie MPC Gt Ge Aa) ee Ske ns ies Gey ie ate

completion with the formation of zygospores or is confined to the
first reaction with the formation of progametes or at the most
gametes.

Although environmental differences not readily controlled in
the cultures may have some influence upon the extent of the sexual
reaction, the genetic constitution of the individual races in the
main must be responsible for their sexual behavior. We have not
succeeded, however, in an attempt to subject the genetic differ-
ences to a factorial interpretation. Distinct classes of plus and
minus races differing sharply in the strength of their sexual activity
or in their capacity to form zygospores or only imperfect reactions
with certain other races do not seem to exist. Thus certain con-
trasts from table VII A may be arranged in such a way that no

214 BOTANICAL GAZETTE [OCTOBER

fewer than five differences in reaction are shown both in the plus
and minus strains chosen to form table IX. A graded series is
indicated which might indefinitely be expanded as more and more
races were tested.

“IMPERFECT HYBRIDIZATION’? BETWEEN SPECIES
Tables IV to VIIA deal with sexual reactions between races
within the individual species concerned. In tables II, VII B, X,
and XI are given the results of contrasting individual races of one
species with those of another species. Many of the contrasts were
made before the species Cunninghamella A was separated from

TABLE Ix
ARRANGEMENT OF SELECTED RACES FROM TABLE VIIA SHOWING

TRASTED: CAPITAL LETTERS INDICATE GRADES OF ZYGOSPORES,
SMALL LETTERS GRADES OF IMPERFECT SEXUAL REACTION.

Plus races
Minus races
217 227 456 779 234
SOB. ee A B C D b
BEG. re B B c D c
Seo. ee B B D O b
ay a a gn B C b O b
eas Pome NRG Se € c d O b

C. echinulata and C. bertholletiae. Those between the testers H
and D and the races of Cunninghamella A were made merely for
the purpose of identifying the sex of the latter, and were not graded,
since they were not originally intended for publication. It has
seemed best, however, to include these and the reactions in table
VII B, since they furnish cumulative evidence in regard to sexual
dimorphism in Cunninghamella. Two races of C. elegans (nos. 496
and 506, respectively plus and minus) failed to show reactions with
the old plus and minus testers of C. echinulata (nos. 885 and 886).
In table VII B certain combinations are starred because in them |
the imperfect hybridization reactions led to the production of
parthenospores (a-zygospores). When certain races of high sexual
vigor are contrasted, gametes which have been formed but which
have been unable to unite may develop into thick-walled sculptured

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 215
spores, which are with difficulty distinguished from the true zygo-
spores. Superficial inspection under low magnifications would
undoubtedly lead to their classification as zygospores, but it is not
unlikely that in our records, especially the earlier ones on C. berthol-
letiae, contrasts may have been listed as weak zygospore reactions,

TABLE X
SUMMARY OF REACTIONS es DIFFERENT SPECIES OF ee
Z INDICATES ZYGOSPORES; SMALL LETTERS INDICATE GRADE
IMPERFECT REACTIONS

C. bertholletiae C. echinulata C. elegans
217 plus 266 minus | 885 plus 886 minus | 406 plus | 506 minus
ee ho ogg
DNS ee fe O c O ¢c

266 mings. Oe c O c O
C. echinulata

O58 WME oo. O Coc pee. | Z O oO

$86 minus... .:.... c O fe eee ne oO O
C. elegans

AO0 Paes O c O OF eee, Z

Writs: c O O O De
TABLE XI

Cunninghamella A: UNGRADED “IMPERFECT HYBRIDIZATION” REACTIONS WITH PLUS
AND MINUS Mucor TESTERS H AND D; H IN BODY OF TABLE
DICATES IMPERFECT REACTIONS

Plus races Minus races
Mucor
515 | 242 | 759 | 260 | 273 | 522 | 182 | 269 | 188 | 95 | 370 | Sit | 245
H plus howe rs Oro ro 0 10 0 (AA te) Baa
D minu HiHiH BAH O1e 10 70.10 ,010

when they should have been called imperfect reactions with forma-
tion of parthenospores. A close examination, especially in the
younger stages, will show that parthenospores develop from single
gametes, and that the suspensor on only one side has a typical
appearance, with what appears to be the suspensor on the opposite
side frequently more or less rounded off and not closely adnate to the
spore. The parthenospores themselves are often distinctly mis-
shapen, but when the zygospores are small, as is true of those of
species of Cunninghamella, it may be difficult to distinguish them

216 BOTANICAL GAZETTE [ocToBER

even with careful inspection. Parthenospores have been obtained
between certain strong races of different species in other genera
with larger zygospores when no doubt of their true nature was
likely to occur after a careful examination. Figures of partheno-
spores formed on homothallic species, at stimulus of contact with
a sexually vigorous race of a heterothallic species, are given in an
earlier publication (9, pl. J). The possible presence of partheno-
spores must not be overlooked in judging reports (19) of true
hybridization between different species in the mucors.

So far as the reactions between different species of Cunning-
hamella have been tested, they argue for the sexual dimorphism
of this genus.

Discussion

The data in the present paper refer only to the mucor genus
Cunninghamella. A preliminary summary has already been given
of tests with other genera (10), and it is hoped to publish a detailed
account of these tests at a later date. The data so far accumulated
show no behavior inconsistent with the idea of a strict sexual
dimorphism. The work, especially with Cunninghamella, indicates
that sex intergrades must be extremely rare if ever present in these
forms, despite the fact that they would be expected on a priori
grounds and the fact that other observers have thought they had
found them.

In the species of Cunninghamella there is apparent a graded
series so far as the strength of sexual activity is concerned, ranging
from a reaction with grade A between sexually strong races to
grade O between sexually weak races. Races which have shown
no reactions in any contrast tested are provisionally listed as
“neutral.” The term neutral is obviously relative, and not meant
to indicate absolute absence of sex. The number of races listed
as neutral for a given collection tends to decrease as more testers
are used in contrasts. Thus it is evident from table VII A that
if strain no. 217 had not been used as a tester, strains nos. 719, 727,
and 725 would have been listed as neutrals rather than as minus
strains, since they would have shown no reaction against any of
_ the plus or minus testers used. Neutrals seem to form the low

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 217

extreme of a continuously graded series of sexual vigor, and the
term as applied undoubtedly includes both plus and minus races.

It is doubtful whether much significance can be attributed to
the proportion of plus and minus races in the collections of the
different species of Cunninghamella as indicative of their relative
distribution in nature. In C. bertholletiae the minus sex seems to
greatly predominate over the plus. In C. elegans the condition is
reversed. The first species was obtained from Brazil nuts bought
in different stores, mostly in or around New York City. Many of
the gross cultures, therefore, may have originated from the same
wholesale shipments. The races may be representative of the
shipments from which they came rather than of the locality where
they were grown. Experience with Rhizopus (4) indicates that in
a mixed culture which is producing zygospores in abundance, one
is likely to isolate almost exclusively one or the other of the two
sexes. The cargo carriers from which the nuts originated may
have been infected chiefly with minus strains. That there is
considerable diversity in sexual vigor of these strains, however, is
- seen from the tables. C. elegans was obtained from different types
of soil around Cold Spring Harbor, and it is possible that collections
from other regions would show a predominance of the opposite sex.

The clearest result from the study of Cunninghamella is the
fact that in 2091 contrasts (2250 including contrasts between
different species of Cunninghamella) made between 202 races from
four different species (see footnote 4) there were none which, if they
showed any sexual response at all, reacted otherwise than as either
a plus or a minus.

Miss Atice M. Pricket, Miss MARGARET CONOVER, and Miss
Mary E. Drummonp have assisted in the progress of the investi-
gation which is here reported.

Summary
1. The terms heterothallic and homothallic are distinguished
as applied to gametophytic sexual differentiation in the mucors.
2. Types of the evidence in support of sex intergrades in hetero-
thallic mucors are given and criticized.

218 BOTANICAL GAZETTE [OCTOBER

3. BURGER’s paper on Cunninghamella, in which he concludes
that sexual dimorphism does not exist in this genus, is discussed
(1) from the standpoint of his own data, (2) from the standpoint
of our experience, and the decision is reached that his conclusion
is not warranted.

4. Data on Cunninghamella elegans, Cunninghamella A (an un-
determined species), C. echinulata, and C. bertholletiae give a total
of 2250 contrasts between a total of 202 races.

5. In C. bertholletiae certain contrast combinations lead to
imperfect sexual reactions when zygospores might be expected.

6. In none of the species were races found which reacted as
sex intergrades.

7. It is concluded that so far as the material investigated is
concerned Cunninghamella is sexually dimorphic.

STATION FOR EXPERIMENTAL EVOLUTION
3 PRING Harpor, N.Y.

LITERATURE CITED

1. BLAKESLEE, A. F. Sexual reproduction in the Mucorineae. Proc. Amer.
Acad. 40:205-319. 1904.

2. ———, Two conidia-bearing fungi, Cunninghamella and Thamnocephalis.
Bor. Gaz. 40:16I-I70. 1905.

, Zygospore germinations in the Mucorineae. Annales Mycol.
4:1-28. 1906

4. , Zygospores and sexual strains in the common bread mold, Rhizopus
nigricans. Science N. S. 24:118-122. 190

, Differentiation of sex in thallus, piccionhyie, and sporophyte.
Bor. Ga 42:161-178. 1906.

6. ———, Nature and significance of sexual differentiation in plants.
Science N. S. 25:366-372. 1

, Heterothallism in bread mold, Rhizopus nigricans. Bot. Gaz.

43: 415-418. 1907.

, Papers on mucors. Bor. GAz. 47:418-423. 1909.

, Sexual reactions between hermaphroditic and dioecious mucors.
" Biol. Bull. 29 :87-103. I9IS5.

10. , Sexuality in mucors. Science N. S. 51:375-382, 403-409. 1920.

II. , Mutations in mucors. Jour. Heredity 11:278-284. 1920.

12. BLAKESLEE, A. F., Wricu, D. S., and CartLepcE, J. L., Technique in
contrasting mucors. Bot. GAz. 72:162-172. 1921.

ee
*

1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 219

13. BurceErr, H., Untersuchungen iiber paaraes Sexualitat, und Erblich-
keit bei Pincouices Flora N. F. 8:353-448. 1915
14. BURGER, OWEN F., Sexuality in Gunaal choaita: Bor. GAz. 68:134-146.

15. Mccoisce. chase i A., Homothallic conjugation in Rhizopus. Bor.
GAZ. 51: 229-230.
cnasenk of the zygospore of Rhizopus nigricans. Bor. Gaz.
ae es 1912.
17. NAMYSLOWSKI, B., Rhizopus nigricans et les conditions de la formation de
ses zygospores. Bull. Int. Acad. Sci. Cracovie 1906. 676-692.
, Etat actuel des recherches sur les oe de la sexualité des
iisrtntes: Rev. Gen. Botanique 32:193-215. 19
. Sairo, Kenpo, and NAGANISHI, HIROSUKE, ene zur Kreuzung
zwischen verschiedenen Mucor-Arten. Bot. Mag. Tokyo 29:149-154.
IQI5.

ot
o

NOTES ON WILLOWS OF SECTIONS PENTANDRAE
ND NIGRAE

CARLETON R. BALL
(WITH FOUR FIGURES)

In 1905 the writer began a series of contributions under the
title, Notes on North American Willows, of which three were pub-
lished.t This general title has been dropped because of the great
disadvantage of not being able to indicate clearly, in the title, the
content and scope of each paper. For this reason the most recent
contribution appeared under a specific title,? as does the present
“one. These data have been derived from studies incident to the
treatment of the genus Salix in various floras and manuals of
botany.’

The location of the herbarium specimens cited is -as follows:
B, herbarium C. R. BALL; C, Canadian Geological Survey, Ottawa;
D, herbarium C. C. Dream, Indiana; F, Field Museum, Chicago;
FBb, Bebb Herbarium in Field Museum; I, Iowa State Agricultural
College; N, United States National Herbarium; N.D., North
Dakota Agricultural College; N.M., New Mexico Agricultural
College; R, Rocky Mountain Herbarium, University of Wyoming.

SALIX SERISSIMA (Bailey) Fernald.—S. arguta* S. pallescens
. Anderss. Svensk Vetensk. Acad. Handl. 6:32. 1867.—S. lucida
serissima Bailey in ARTHUR, Bull. Geol. Nat. Hist. Survey Minn.

t Bot. Gaz. 40:376-380. pls. 12, 13. 1905; 60:45—-54. figs. 3. 1905; and 60:
391-399. 1915.

2 Batt, C. R., Undescribed willows of the section Cordatae. Bor. Gaz. 71:
426-434. fig. I. 1921.

3 Barr, C. R., Salix in Courter and Netson, Man. Bot. Rocky Mt. Region,
pp. 128-139. 1909.
, Salix in Prrer and BEartie, Flora of the Northwest Coast, pp. 113-118.

IQI5.

———, Salix in P. C. Stanpey, Flora of Glacier National Park, Contrib. U-S.
Nat. Herb. 22:319-324. 1921.
, Salix in Cuas. C. Dean, Trees of Indiana, revised ed., pp. 34-45. Pls.
IO-I4. 1921. m

Botanical Gazette, vol. 72] 220

1921] BALL—WILLOWS , [221

3:19. 1887.—S. serissima (Bailey) Fernald, Rhodora 6:7. De-
cember 28, 1903.

When this species was established by FERNALD, in the very
interesting and comprehensive article cited, he fully set forth its
ecological characters and catalogued all available herbarium speci-
mens. ‘These showed its range to extend westward from Connecti-
cut to northern Ohio, Wisconsin, and northern Minnesota. The
type locality in Minnesota, and the most westerly station then
known, was Mud River, Vermillion Lake, Saint Louis County,
lying in the extreme northeastern part of the state, about 75 miles
north of Duluth. Rosrnson and FERNALD‘ extended the range to
Alberta, while the writers has reported the species from Teton
County, Montana. SCHNEIDER extends its range eastward to
Newfoundland, north to the eastern shore of James Bay and the
Severn River in Keewatin, and west to Edmonton, Banff, and
Crow’s Nest Lake in Alberta. The specimens cited later extend
the range southwestward to Pembina and Rolette counties in
North Dakota, and to Flathead County in extreme northwestern
Montana. Both the Montana specimens come from the east side
of the Continental Divide. Teton County lies on the plains at
the eastern base of the Rocky Mountains, at an average elevation
of about 4000 ft. Choteau is on the Teton River, which arises in
the high mountains, but here flows eastward through the plains to
the Missouri River. The localities in North Dakota are a south-
ward extension of the distribution in Manitoba, while those in
Montana obviously represent a similar extension of its distribution
in the mountains of Alberta. It is quite possible that further
search will extend the range both north and south in the Rocky
Mountains. The Kennicott specimen from Slave River extends
the range far to the north of Edmonton, into Athabasca or
Mackenzie.

Montana.—Choteau County, Choteau, on Teton River, about 4000 ft.
elevation, lat. 112°10’ W., Griffiths and Lange, August 22, 1900 (B); Flathead
County, 3-4 ft. high in open marsh along Swiftcurrent Creek below Lake
McDermott, alt. about 1350 m., P. C. Standley 16053, July 20, 1919 (B, N).

4Rosinson and FERNALD, in Gray, New Man. Bot. 322. 1908.
’ Bart, C. R., in Courter and Netson, New Man. Rocky Mt. Bot. 130. 1909.

222 BOTANICAL GAZETTE [OCTOBER

ALBERTA.—Crow Nest Lake, Rocky Mountains, J. Macoun 39 (Geological
Survey Canada 94,440), August 8, 1897 (B); Rocky Mountains Park, Banff,
low ground near the village, alt. 4500 ft., W. C. McCalla 2252, shrub 6 ft. tall,
June 19, 1899 (N); vicinity of Banff, NV. B. Sanson 304, July 14; 307, 309;
315A, 2167, July 15; 2173, June 27, 1911 (B); Calgary, J. Macoun 16 (Geo
logical Survey Canada 94, 336), June 5, 1897 (B); Grattan Creek, near Battle
River, Macoun and Herriot (Geological Survey Canada 70,252), August 17,
1906 (B).

ATHABASCA or MACKENZIE.—Slave River, R. Kennicott, July 1860 (N).

ManitTosa.—Bog north of Carberry, Macoun and Herriot (Geological
Survey Canada 70,262), June 11, 1906 (B); near Sidney, Macoun and Herriot
(Geological Survey Canada 70,263), June 12, 1906 (B) (70,264), June 13,
1906 (B).

NortH Daxota.—Rolette County, Turtle Mountains, woods around
Upsilon Lake (Fish Lake), D. C. Mabbott 464, September 7, 1917 (B); Pembina
County, Walhalla, L. R. Waldron 1666, August 16, 1902 (B, ND).

ANDERSON in 1867 published S. arguita* S. pallescens hiriis-
guama, based on a specimen collected by BourGEAU at Lake Win-
nipeg and having short aments on short peduncles, scales densely
white pilose except at tips, and narrow, sharply serrate leaves.
Throughout its range S. serissima has short aments and pilose
scales, but not narrow and sharply serrate leaves. The three
Manitoba specimens cited do have such leaves, and it is quite
possible that they represent this form. ‘The leaves are not quite
fully developed, and it seems hardly desirable to designate them
as belonging to it without more and older material. On no. 70264
the under surfaces of the leaves show scarcely any traces of glauces-
cence. The leaves of all three are discolored in drying, however,
which tends to obscure this character.

On flowering specimens from Manitoba (Macoun and Herriot
70262) and Alberta (Sanson 304, 309, 2167), a peculiar appearance
has been observed. The capsules, nearly or quite full sized, but
not mature, are minutely roughened or papillate, and the surface,
viewed by reflected light, has a striking and deceptive resemblance
to a fine lustrous puberulence.

SALIX LASIANDRA Bentham.—S. lasiandra Benth., Pl. Hartweg,
335. 1857.—S. speciosa Nutt., N. A. Sylva. 1:58. pl. 17. 1843.
not Host, 1828, or HOOKER and ARNOTT, 1832.—S. arguta lasiandra
Anderss. Svensk. Vetensk. Akad. Handl 6: 33. 1867 (Monog. Sal.).

1921] BALL—WILLOWS 223

—S. lasiandra Lyallii Sargent, Gard. and For. 8: 463. 1895.—
S. Lyallii (Sarg.) Heller, Bull. Torr. Bot. Club 25: 580. 1898.

This beautiful species was described by BENTHAM from a
staminate specimen, no. 1954, collected by HARTWEG on the Sacra-
mento River in California. The cotype in the Gray Herbarium
is a twig about 12 in. long, not fully in anthesis. The expanding
leaves are only 2-4 cm. long and 5-9 mm. wide. The aments are
4cm. long by 5-9 mm. wide.

The species had previously (1843) been described by NUTTALL
from specimens observed abundantly on the Oregon and Wahlamet
(Columbia and Willamette) rivers, and occasionally as far east as
the Blue Mountains and the Boiseé (Snake) River.

It is a curious coincidence that FENDLER’s no. 816, collected
near Santa Fe, New Mexico, and made by ANDERSSON the type of
his S. Fendleriana, also is a staminate specimen with the aments
not yet fully in anthesis and the leaves just unfolding. SCHNEIDER
regards this specimen also as representing the true S. lasiandra
rather than the green-leaved S. caudata, because, as he states, in
some of the cotype specimens he has examined the leaves are more
fully developed and show the glaucous under surface. ‘Two speci-
mens of this number in the National Herbarium are not sufficiently
developed to show this.

The range of this species has been discussed recently by
SCHNEIDER (Jour. Arnold Arb. 1:17. 1919). Its distribution in
Colorado and New Mexico, the southeasternmost extension of its
range, is so restricted, and in a way so separated from the remainder,
that the specimens known from these two states are listed below,
in order to stimulate the interest of botanists.

CoLoraDo.—Montrose County, Cimarron, Gunnison River, alt. 6900 ft.,
C. F. Baker 141, June 15, 1901 (N); San Miguel County, Norwood Hill, river
banks, alt. 7ooo ft., E. P. Walker 453, August 11, 1912 (N); Archuleta
County, Piedra (creek), E. O. Wooton 2718, August 12, 1904 (N, NM).

New Mexico.—Rio Arribo County, Nutritas Creek below Tierra Ama-
rilla, alt. 2250m., W. W. Eggleston 6636, April 18-May 25, rorr (N);
meadows, vicinity of Chama, alt. 2380-2550 m., P. C. Standley 6645, July 9,
torr (N); Sante Fe County, Sante Fe Canyon, 9 miles east of Sante Fe, alt.
8000 ft., A. A. and E. G. Heller 3637, June 2, 1897 (N); Sante Fe Creek, 4 .
miles east of Sante Fe, alt. 7500 ft., A. A. and E. G. Heller 3719, June 27,

224 BOTANICAL GAZETTE [OCTOBER

1897 (N); McKinley County, north of Ramah, Z. O. Wooton, pe 25, 1906
(NM); Socorro County, Mogollon Mountains, middle fork of Gila River,
alt. about 7000 ft., E.'O. Wooton, August 4, 1900 (N); west fork 7: Gila River,
alt. 6800 ft., Woeion. August 6, 1900 (N, NM); northwest of Mogollon Moun-
tains, Lower Plaza, Frisco, alt. 5800 ft., Wooton, July 25, 1900 (N, NM);
Frisco River, near Frisco, alt. 5800 ft., Wooton, July 25, 1900 (N).

SALIX LASIANDRA Abramsi, n. var.—Leaves narrowly lanceolate,
5-11 cm. long, 1-17 cm. wide, common sizes 6-7 X1, 7-8 X1-1.5,
and g-11X1.5cm., margins shallowly serrulate to subentire;
petioles short, 4-8-10 mm. long, thinly pubescent to glabrous, the
glands of the distal upper surface small and inconspicuous or
wanting; aments short, usually 2-3, sometimes 4.cm. long; cap-
sules 5.5-7 mm. long; pedicels 1-1.5 mm. long.

This variety is named for Professor LERoy Asrams, of the Department of
Botany of Stanford University, California, well known for his contributions
to Pacific Coast botany and collector of the type specimen, his no. 4493, “near
Sentinel Hotel, Yosemite Valley, Yosemite National Park, alt. 4000-4500 ft.,”
on June 23, 1911. It differs from the species chiefly in the smaller and nar-
rower, less serrulate leaves, and the nearly eglandular petioles. It seems to
be limited in its distribution to the Sierra Nevada of central eastern California, ©
from Plumas County, south to Fresno County. Nearly all the specimens
collected by Duprey in Nevada and El Dorado counties are immature and
not identifiable with absolute certainty.

CaLrFoRNIA.—Sierra County, vicinity of Gold Lake, 1940 m., W. W.
Eggleston 6263, 6265, August 28, 29, 1910 (N); Nevada County, lower end of
Donner Lake, A. A. Heller 6879, July 8 (N, St.) 6943, July 16, 1903 (N, St.);
vicinity of Donner Lake, W. R. Dudley 3007, 5008, June 12; 5018, 5026, 5027,
5049, June 14; Soda Springs station, Dudley 5138, June 15; flat land of the
Yuba River opposite Cascade, Dudley 5149, 5150, June 15; by Truckee River,
1.5 miles below Truckee, Dudley 5155, June 17; Independence Lake, by outlet
bridge, Dudley 5276, 5277, June ro (all St.); Placer County, Monte Vista,
Dutch Flat, W. R. Dudley (fol.), August 1909; El Dorado County, Glen Alpine
Springs, W. R. Dudley 5660, June 1900 (St.); between Glen Alpine Spring and
Camp Agazziz, Dudley 5664, June 27 (St.); Tallac House, Lake Tahoe shore,
Dudley 5725, June 28, 1900 (St.); Glen Alpine, 6800 ft., E. A. McGregor 204,
August 26, 1909 (St); Mariposa County, Mirror Lake, W. R. Dudley, June 12)
1894 (St), Yosemite National Park; near Sentinel Hotel, alt. 4000-4500 ft.,
L. R. Abrams 4493 (fem. type), June 23, torr (St); Merced Canyon, near
Cascade Creek, 3500 ft., Abrams 4684, July 12, 1911 (St); Fresno County
_ region of Sidney Creek, 5300 ft., Hall and Chandler 360, June 25-July 15
tgoo (St).

1921] BALL—WILLOWS 225

SALIX CAUDATA parvifolia, n. var.—-In the northern part of the
range of S. caudata is found a form of lower stature and with

Fic. 1.—Portion of type specimen of Salix caudata parvifolia n. var. (nat. size)

shorter, narrower leaves (fig. 1). It occurs rather commonly and
appears to be the dominant form in the mountains of northwestern

226 BOTANICAL GAZETTE [OCTOBER

Montana and southern Alberta. While examination of a large
number of specimens indicates that it passes gradually into the
more typical form of the species, as.do many other varieties, its
recognition as a variety should help to a better understanding of
the range of expression in S. caudata. Little is known of its height
other than the notes given by STANDLEY, which indicate a lower
stature than that of the species. The branchlets frequently are
shorter and more divaricate; the leaves are very small, 5—8 cm.
long, 7-12 mm. wide, seldom exceeding 1 cm. in width, common
sizes being 6cm.xX8mm., 7cm.Xg-10 mm., or on sterile shoots
8-10 cm. X11-16mm., strongly glandular-serrulate, as are the
stipules also. The aments are 2-3 or 3.5 cm. long, rather lax; the
scales 3-3.5mm. long, linear-lanceolate, acute to truncate or
toothed, and glabrate. The capsules are 6.5-8 mm. long.

The range of variety. parvifolia is in the Rocky Mountains from Banff,
Alberta, to the Yellowstone Park in Wyoming and the Wahsatch Mountains
near Ogden, Utah, also in the mountains of western Idaho and eastern Oregon,
and westward in Oregon to the eastern slope of the Cascades in Wasco County.

ERTA.—Rocky Mountains Park, NV. B. Sanson 164 m., June 17, 1911
(B); 265, July 5, 1911 (B); 413, 414, August 21, 1911 (B); 2056, June 22,
1912 (B).
MonTAanaA.—Flathead County, Glacier National Park, 6-8 ft. high, boggy
meadow, along Swiftcurrent Creek, below Lake McDermott, alt. about 1350
m., P. C. Standley 16865 (type) August 1, 1919 (N); thicket along lake, abun-
dant, very slender, 6-12 ft. high, vicinity of Glacier Hotel (‘‘Lewis’s”), at head
of Lake McDonald, alt. 900-1050 m., Standley 17906, August 22, 1919 (N);
Deer Lodge or Powell counties, Deer Lodge Valley, mountain streams, 5000
ft. ubaat J.W. Blankinship 788, m. f., May 27, 1906 (N).

Wyominc.—Yellowstone National eck. Upper Fire Hole Basin, Yellow-
stone bake J. M. Coulter, Hayden Survey, July 1872 (N 253728, fr.); along
Lamar Creek, J. N. Rose 406, fr., August 20, 1893 (N).

Ipano.—Fremont County, dene an irrigating ditch, St. Anthony, Merrill
and Wilcox 899, fr., July 6, 1901 (B, N); Washington County, Weiser, alt.
2200 ft., M. E. Jones 6548, July 5, 1899 (N)._,

OrEGON.—Union County, a small tree, bank of Catherine Creek, alt. 3500
ft., W. C. Cusick 2385, m. f. fr., May 30, June 28, 1900 (N); Grant County,
Prairie City, alt. rog4om., W. W. Eggleston 13700, September 5, 1916 (N);
Wasco County, along streams in yellow pines, near head of Warm Springs
River, alt. 3000 ft., HE. I. Applegate 2777, September 7, 1898 (N).

Ur die: Mountains near Ogden, Hayden’s Expedition, 1872 (N, sheet
26198 in part, with S. lutea Nutt.).

1921] BALL—WILLOWS 227

SALIX LucIDA Muhl.—I am at a loss to understand the dis-
cussion of the distribution of this species by SCHNEIDER. In his
discussion of S. /asiandra (p. 16) he says:

In 1867 ANDERSSON created two new:species: S. arguta and S. lancifolia.
Laas S. arguta he referred his S. Fendleriana of 1858 as a synonym, but only

““p. p.”” Nevertheless he cited both specimens upon which he previously based
his species, and added to them in the first place a specimen collected by Bour-
GEAU “‘ad fl. Saskatchavan, prope Carlton-house.” This specimen (I have not
yet seen the type in Herb. K.) probably belongs to S. Jucida, and is identical
with one of BourGEAU’s specimens from the “Saskatchevan, 1859,” preserved
in Herb.G. Therefore the typical S. argenta of ANDERSSON consists of three
different things, namely S. Jucida (Bourgeau)—.

From this it would seem that SCHNEIDER thinks S. lucida is
represented in Saskatchewan by two collections of BOURGEAU.
Under S. lucida he states:

There is likewise no proof that it occurs in Manitoba, Assiniboia, Saskatche-
wan, northeastern Alberta, Athabasca, and the Northwest Territories as far
north as Great Bear Lake. Apparently S. serissima and S. lasiandra have
been taken for S. lucida, of which the northeasternmost locality from where
T have seen material is the Hill (or Hayes) River in Manitoba (R. Bell, August
1880, no. 24585, fr.; O.). But it seems very rare (or represented by S. seris-
sima) in these regions and in western Ontario, becoming frequent to the east
of Lake Huron in southeastern Ontario and southern Quebec.

The first two sentences are contradictory. One says that there
is no proof of the occurrence of S. lucida in Manitoba, Saskatche-
wan, etc. The second states that the ‘‘northeasternmost”’
biortiiweverinset ?) locality from which S. lucida is known by
him is in Manitoba, and he cites a specimen in the herbarium of
the Canadian Geological Survey. Although the writer has seen
no specimens of S. /ucida from Manitoba, there is a strong proba-
bility that it occurs in that province. S. serissima, however, is
much more common there, at least in a narrow-leaved form.

SALIx Gooppincu Ball.—S. Gooddingii Ball, Bort. Gaz. 40:
376. pl. 12, figs. 2. 1905; SCHNEIDER, Bort. Gaz. 65:12. 1918;
SCHNEIDER, Jour. Arnold Arb. 1:9. 1919.—S. nigra of numerous
authors, not MarsH.—S. nigra vallicola Dudley in ABRAMS, F1. Los
Angeles and vicinity. 100. 1904.—S. vallicola (Dudley) Britton,
N. A. Trees 184. fig. rgr. 1908.

228 BOTANICAL GAZETTE [OCTOBER

This species was described in 1905 from a single collection of
immature and somewhat parasitized pistillate specimens, and at
that time placed in the section LoncrroLiAE. Not long after describ-
ing it, I was indebted to Professor W. W. Row tee for calling my
attention to the fact that the species belonged rather in the NIGRAE,
and that GOopDING’s no. 719 represented the staminate plant.

Fic. 2.—Salix Gooddingii Ball: large trees on levee at border of Arizona Agri-
cultural A Bien: Substation, near Yuma, Arizona, showing form produced in
open grov

Such an error would scarcely have been made if mature specimens
had been in hand. In the present instance the type specimen,
with its puberulent to pubescent branchlets and tomentose cap-
sules, constitutes so striking a departure from the characters so
long associated with the species of section NicrAr, and agrees
superficially so well with those of far western members of the
LONGIFOLIAE, that the deception was complete. Recently the
writer has studied the numerous older collections of this species
as well as some more recent material. Some interesting notes on
habit, size, etc., have been obtained by Mrs. AGNES CuaseE and the

1921] BALL—WILLOWS 2209

writer (figs. 2-4). The rather abundant material and the fuller
notes now permit a complete description of the plant, as follows:

Shrub 3 mm. tall, to tree 3-9 dm. in diameter and at least 12
and probably 15m. in height; bark furrowed, gray; branchlets
straight, slender, yellowish, glabrous to puberulent, more or less
shining, seasonal twigs usually densely pubescent to subpilose;
bud scales small, 2-4mm. long, color and pubescence as in
branchlets.

Leaves numerous; stipules 1-3 mm. long, or 8—-1o mm. long on
vigorous shoots, semiclordate to subreniform or sublunate, glandular-
denticulate to dentate, often densely glandular on the upper
(inner) surface also (see Ball 1821, 2069; Chase 5517); petioles
3-6 mm. long, yellowish, densely pubescent to glabrate; blades
linear-lanceolate, usually somewhat falcate, 8-15 mm. wide, 6-10
cm. long, commonly 8 mm. by 8 cm., on new shoots up to 2.4 by
15cm., usually acute at base, acuminate at apex, margins finely
and shallowly glandular-denticulate with about 8 teeth per cm.,
green or yellowish green on both sides, often pubescent or puberu-
lent until half grown, usually glabrous at maturity or the midrib
beneath permanently pubescent; veins prominent above.

Aments coetaneous, numerous, solitary, terminating lateral
leafy peduncles 2—4 cm. long, and bearing 3—6 small leaves; rachis
densely pubescent to pilose; scales oblanceolate to lanceolate-
oblong, or the staminate obovate, occasionally toothed or even
lacerate at apex, 2.5-3 mm. long, yellow, more or less densely pi-
lose, sometimes nearly glabrous on outer apical portion, deciduous;
pistillate aments (originally described from immature parasitized
specimens) 3-6 or 8 cm. long, 1.5-2 cm. wide, lax; capsules ovate-
conic, 5.5-7 mm. long, roughened, thinly to densely pilose with

gray hairs at anthesis, becoming glabrous at maturity; pedicels
2-3 mm. long, pilose, becoming glabrous; style less than 0.5 mm.
long; stigmas divided, o.3-0.5 mm. long; staminate aments 4-6
or 7cm. long, 1-1.2 cm. wide; stamens 5-6, filaments pilose on
lower third or half. :

S. Gooddingii is found along streams and about springs from southwestern
New Mexico to southern Nevada (Lincoln County), Baja California, and
thence northward through the interior of California to Tehama County, in

230 BOTANICAL GAZETTE [OCTOBER

Fic. 3.—Salix Gooddingii Ball, showing forms produced under conditions of
previous over-crowding; near Yuma Experiment Farm of U.S. Department of Agri-
culture, in California, near Yuma, Arizona.

1921] BALL—WILLOWS 231

the vicinity of Red Bluff. It is most abundantly distributed in the valleys,
having an elevation of only 0-200 ft., but ascends the foothills streams to
1500 ft. or more. The specimens listed later are referred to this species. The
arrangement is from east and south to west and north. According to
SCHNEIDER, this species is found as far east as the Rio Grande Valley in south
central New Mexico and in the Davis Mountains of southwest Texas. The
material from those districts is discussed later.

EW MeExico.—Grant County, Dog Spring, EZ. A. Mearns 183 (tree 25 ft.
high, 1 ft. in diam.), May 29, 190 (3?) (N); Dog Spring, Dog Mountains,
Mearns 2419, September 22, 1903 pu tree 20 ft. high, Emory Spring, at foot
of Emory Peak, Mearns 277, June 4, 1902, (N); near Kingston, in meadows,
at 6600 ft. elevation, O. B. Metcalfe oS 1904 (N); Mangas Springs, 18 miles
northwest of Silver City, alt. 4770 ft., Meicalfe, ee 26, 1903 (N); Gila,
alt. 4200 - E. A. Goldman 1561, October 9, 1908 (N

Arizona.—Graham County, Sierra Bonita Ranch, 23 nantes north of Willcox,
R.A. pr 1904 (B); Duncan, J. N. Rose 11737, April 1908 (N); Cochise
County, Ft. Huachuca, Dr. Edward Palmer 452, April 26-May 21, 1890 (N);
Dr. Patzky (?), 1890 (N); T. E. Wilcox 1894 (N); Chiricahua Mountains,
Joe Smith’s Ranch, alt. 5500 ft., J. C. Blumer 2306, November 22, 1906 (B);
Bonita Canyon, alt. 6500 ft., Blasi mer 2300, Miah 4, 1906 (B); Santa Cruz
County, Nogales, J. Tilston: March 28, 1908 (B): near Santa Cruz River,
east of Nogales, Tidestrom 743, March 30, 1908 (B): Sonaita Creek,
Patagonia, F. M. Chamberlain 5, April 2, 1904 (N); in creek bed at Patagonia,
Tidestrom 814, April 10, 1908; Calabases, common in bottom lands, Tidestrom
870, April 21, 1908 (B), same locality, Tidestrom 886, April 24, 1908(B); Pima
County, Canoa to Arabaca (Arivaca) D. Griffiths 3667, March 13-April 23,
1903 (N); Tucson, Mearns 178 (2658) November 21, 1893 (N); J. J. Toumey,
April 13, May 20, 1894 (N); March, May 16, 1896 (N); Myrile Zuck, May 16,
1896 (N); G. R. Vasey 266, March 1881 (N); J. N. Rose 11767, April 16, 1908
(N); Rose, Standley, and Russell 15192, April 27, 1910 (N); Blumer B 16,
alt. 2400 ft., April 15, 1907 (B); Santa Cruz River, near Tucson, Blumer B
16a, May ro, 1907 (B.N,); Santa Catalina Mountains, alt. 3000 ft., Blumer
B 17, April 25, 1907 (B.N,); Santa Rita Mountains, Andrade, Griffiths 4079,
April 18, 1903 (B.N.); Pinal County, near Dudleyville, Griffiths 3666, March
13-April 23, 1903 (N); Yuma County, Yuma, State Experiment Substation,
C. R. Ball 1740, 1741, June 15, 1911 (B,N); Ball 1901, May 26, 1915 (B,N);
Mohave County, Topock, abundant along Colorado River, alt. 600 ft., EZ. A.
Goldman 2970, September 27,1917 (N); Beaverdam, alt. 1800 ft., M. E. Jones
5020, April 5, 1894 (N); Littlefield, near petrified springs, J. Tidestrom 9236,
April 29, 1919 (B); at spring 8 miles above Pierce’s Ferry, alt. 1700 ft., Jones
5077u, April 18, 1894 (N); locality unknown, Fremont’s Expedition to Cali-
fornia, no. 202 (A), 1845 (N), has “Utah” written on label, but “Ariz.” added
by same hand that added number and date; Beaver Creek, B. E. Fernow,
August 1896 (N)

[OCTOBER

Fic. 4.—Salix Gooddingii Ball, showing character of bark on large trees, near
those shown in fig. 2.

1921] BALL—WILLOWS 233

NeEvapa.—Lincoln County, Muddy Creek (R) near Virgin River, L. N.
Goodding 6809, (type), May 2, 1602 (B, N); Rioville, Colorado River, Goodding
719, May 6, 1902 (B, N); along ditches, Bunkerville, J. Tidestrom 9202, May
27, 1919 (B); Nye County, Ash Meadows, Coolie and Funston 2145, March
1891 (N), sub nom. nigra venulosa.

Mexico.—Baja California, Seven Wells on Salton River, E. A. Mea
2869 (Internat. Boundary Commission), April : 1894 (N); L. Schoenefeldt
2877 (Internat. Boundary Commission) April 9, 1804 (

CALIFORNIA.—Mexican Boundary, Unlucky sega - Schoenefeldt 2918,
May 1, 1894 (N); Imperial County, Yuma (Fort Yuma Indian Reservation)
pumphouse at ferry, C. R. Ball 1741, June 15, 1911 (B); Indian Reservation,
Agnes Chase 5517, April 7, 1910 (B); Salton Basin, S. B. Parish 8092a,
June 30, 1912 (B); San Diego County, Bernardo, San Dieguito River, L. R
Abrams 3371, May 2, 1903 (N); Pine Valley, E. A. Mearns 3977, August 12,
1894 (N); Orange County, Santa Ana River, near Orange, L. R. Abrams 3256
(type of S. nigra vallicola Dudley) April 16, 1903 (N); San Bernardino County,
Colton, M. E. Jones 3195, April 28, 1882 (N); Fort Mojave, Mojave River,
J. G. Cooper, March 25, 1861 (N, 319845); undated (N, 319846); Inyo

foe Sed

Coville and Funston 262, February 6, 1891 (N); Furnace Creek Ranch
house, Death Valley, Coville and Funston 469, March 24, 1891 (N); Kern
County, on the Tulare Plains, about 10 miles south of Bakersfield, alt. 400 m.,
Coville and Funston 1236, July 13, 1891 (N); Tulare County, Hanford, Alice
Eastwood 3846, 3851, March 24, 1914 (N); Visalia, Eastwood 34, May 11, 1804
(N); Madera County, Fresno River, J. W. Congdon, June 21, 1903 (N);
powerhouse no. 1, San Joaquin River, alt. 1000 ft., E. G. Dudley 5, November
1911 (B); San Joaquin County, large tree, 10-18 in. diam., in Tom Payne’s
or Paradise Cutoff, Tracy pike, about ro m. south of Stockton, C. R. Ball 1920,
June 1, 1915 (B, N). Amador County, Sutter Creek, Ione, C. H. Merriam a,
September 15, 1905 (letter) (N); South Jackson, 1500 ft., Geo. Hansen 108,
July 3, 1892 (N); Sacramento County, Sacramento, L. F. Ward 89, October 1,
1895 (N); Sacramento Valley, Wilkes Exploring Expedition 1234 (N); Lake
County, bank of Cache Creek, H. N. Bolander 2678 (N), 1863; Clear Lake
(not certainly in Lake County), J. T orrey 490 (N), 1865; Yolo County, near
Madison, A. A. Heller 5419, April 29, 1902:(N); Rumsey, C. F. Baker 2936,
May 7, 1903 (N), Butte County, Biggs, near United States Experiment Farm,
C. R. Ball 1820, 1821 (B, N), 1822, 1824 (B), August 15, 1913; same place,
Ball 1939 June 4, rors (B, N); Chico, bank of Chico Creek, Bail 2069, June 15,
1916 (B); Tehama County, Red Bluff, L. E. Smith, 596, 599, 600, March 26,
1914 (N); 668, 669, May 8, 1914 (N); Shasta County, Reed Creek, L. E.
Smith 610, March 30, 1914 (N).
In addition to this distribution, SCHNEIDER (Bot. Gaz. 65:12-13. 1918;
Jour. Arnold Arboretum 1:9. 1919) credits S. Gooddingii with an eastern
extension of range to central southern New Mexico and southwestern Texas

234 BOTANICAL GAZETTE [OCTOBER

(not ‘‘northwestern,” as SCHNEIDER states). The specimens so determined

by him are listed later. Two chief districts are involved. The localities in

00
miles to the southeast, forming part of the watershed between the Rio Grande
and the Pecos rivers. I am by no means convinced that all of this material
represents S. Gooddingii instead of a form of S. nigra.

New Mexico.—Dona Ana County, on the White Sands, alt. 3700-4000
ft., E. O. Wooton, August 24, 1899 (N, 3 sheets, twigs brown

TExAs.—El Paso County, near El Paso, G. R. Vasey, March 1881 (N, 2
sheets); Vasey 267, April 1881 (N, 2 hese: V. Havard, November 1881 (N);
without locality, Havard, 1881 (N 264239); Mexican Boundary Survey, chiefly
-In the valley of the Rio Grande below Donana, Parry, Bigelow, Wright, and
Schott Poa (N); Jeff Davis County (pisbably): Fort Davis, V. Havard,
April 1885 (N); Davis Mountains, S. M. Tracy 187, April 24, 1902 (N);
Tom Green County, Knickerbocker Ranch, along Dove Creek, Frank Tweedy,
May 1880 (N) (strongly suggests S. nigra Lindheimerii Schn.).

SALIX LAEVIGATA araquipa (Jepson), n. var.—S. laevigata forma
araquipa Jepson, Fl. Calif. 339, 1909.—The original description by
Jepson reads as follows:

Forma araguipa Jepson, n. form. Small tree; one-year-old shoot with
dense close tomentum; brown tuft of hairs on old wood at base of season’s
shoot very conspicuous; leaves reddish brown above; catkins long and dense.
Arbor parva ramulis annotinis cum denso appresso tomento; valde manifestus
caespes fusci pili basi horni ramuli in ligno vetere; folia rufo-fusca supra;
amenta longa artaque.—Dry gulches, Araquipa Hills, Solano County, May 2-6,
1891, W. L. J

The type came from “dry gulches, Araquipa Hills, Solano
County (California), May 2-6, 1891, W. L. Jepson.’ This county
lies northeast of San Francisco. I have not seen the type specimen,
but an examination of the material in the National Herbarium, as
well as that in my own herbarium, shows that this variety is found
rather rarely in central California, but occurs commonly in the
southern part of the state, comprised in Los Angeles, Orange,
Riverside, San Bernardino, and San Diego counties. The vesture
of the seasonal twigs, the buds, the petioles, and even the basal
portion of the midrib, especially beneath, makes such a striking
contrast with the glabrous and shining epidermis of the typical
form that forma araguipa seems worthy of varietal rank. It
should be noted, however, that the conspicuous tuft of brown hairs

1921] BALL—WILLOWS 235

at the base of the seasonal shoots is found on many specimens of
which the shoots themselves are glabrous. The following specimens
are referred to this variety:

CALIFORNIA.—Sonoma County, near Sonoma, A. A. Heller 5348, April 23,
1902 (N); San Bernardino County, San Bernardino, G. R. Vasey 265, February
1881 (N); S. B. and W. F. Parish 1204, 1881 (N); alt. 300m., J. B. Leiberg
3243, 3244, both in part, April 4, 1898 (N); Los Angeles County, Rivera,
E. Braunton 364, May 10, 1902 (N); Los Angeles River near Rivera, L. R.
Abrams 3253, April 14, 1903 (N); San Francisquito Canyon, elevation 1500 ft.,
W.M. Moore, October 7, 1912 (B); Orange County, Santiago Canyon in Santa
Ana Mountains, V. Bailey 1185, July 17, 1907 (N); Riverside County, Bar-
ranca, in mountains east of Pigeon Pass, F. M. Reed 2279, March 15, 1908 (N);
San Diego County, Campo, by streams, C. G. Pringle 332, April 18, 1892 (N);
Fall Brook, M. E. Jones 2870, March 25, 1882 (N); Jacumba Hot Springs,
near Monument 233, E. A. Mearns 3245, May 20; 3322, May 28, 1894 (N);
Warner’s Hot Springs, Alice Eastwood 2589, April 9, 1913 (N).

Arizona.—Beaver Creek, B. E. Fernow, August 1896 (sub nom. amygda-
loides) (N).

SALIX LONGIPES Warpit (Bebb) Schneider.—S. nigra Wardiz
Bebb, U.S. Nat. Mus. Bull. 22. 114-115. 1881.—S. longipes Wardii
(Bebb) Schneider, Bor. Gaz. 65:22. 1918.

_ So far as known, this species has not been reported heretofore
from any station north of the Ohio River. In the autumn of 1918,
a specimen collected on the banks of the Ohio, in Perry County,
Indiana, was found in a collection of Indiana willows received for
identification from CHarLes C. Dram, State Forester of Indiana.
On asking his interest in getting more material, he was kind enough
to visit the spot again in 1920 and make another collection. Both
specimens show only the characteristic foliage, but there can be no
‘doubt of their identity.

Inp1aNa.—Perry County, low bank of Ohio River about 6 miles east of
Chnsetions Chas. C. Deam 26749, September 24, 1918 (B,D); same place, a
sprawling shrub growing in crevices of rock, the branches about 3 ft. tall,
probably Legere oe during the winter, at least, Deam 33220, October 1,
1920 (B,

The ou northern range of the species is from Washington, D.C.,
northwestward up the Potomac Valley to Alleghany County, Maryland, and
westward in Upshur County, West Virginia (about lat. 39° N.), and Fayette
County, Kentucky (about lat. 38° N.). Neither Upshur County nor Fayette

236 BOTANICAL GAZETTE [OCTOBER

County is near the Ohio River, although the latter is in the same latitude
as Perry County, Ohio, and less than roo miles east of it.

SALIX AMYGDALOIDES Andersson.—This species is mentioned
only to note extension of its range into two states excluded by
SCHNEIDER, who in the main has set very accurate boundaries for
its distribution. These states are Arizona and New Mexico.
These specimens bear mature ovate-lanceolate leaves, and there
can be no doubt of their identity, as those of S. Wrighti are
linear-lanceolate and shorter-petioled.

ARIzONA.—Navajo Indian Reservation, Tunicha Mountains, 7000 ft.,
E. A. Goldman 2909, August 20, 1917 (N).
New Mexico.—San Juan County, near Farmington, 1550-1650 m.;

; ey I N.
of Shiprock Agency, 1425 m. elevation, Standley 7867, August 11, rg11 (N).

These localities are in the extreme northeastern corner of Arizona and the
extreme northwestern corner of New Mexico, respectively.

It may be worth noting also that the excellent survey of Indiana being
made by Cuas. C. Dream, State Forester, shows, by specimens I have seen,
that S. amygdaloides occurs in fifteen counties in the northern third of the
state (3-4 tiers of counties), and at two outposts, Henry and Marion counties
in the central part of the state.

BuREAU OF PLANT INDUSTRY
Wasuincton, D.C

POLYPODIUM VULGARE AS AN EPIPHYTE!

DuNCAN S. JOHNSON

(WITH THREE FIGURES)

While Polypodium vulgare is common on rocks, may often grow
on the trunks of fallen trees, or sometimes even creep a few feet
up living trunks, Ihave not been able to/ffind a definite report of
its being really epiphytic in habit in the United States. ScHIMPER,’
the first general student of. American epiphytes or air plants, says
(1888, p. 131):

In the North American forests’ the shade plants of the soil would not be
able, because of lack of moisture, to grow on. the bark of trees. Thus the so
common Polypodium vulgare ascends to the trees in North America, just as
little as it does in central or northern Europe.

Observations made:at Cockeysville near Baltimore, Maryland,
latitude 39° 30’ N, shows that this polypody can grow-and fruit
for years as.a true epiphyte, high up on'the erect branchless trunks
of living trees. The ferns were not growing in an unusually moist
region, as was true of the epiphytic individuals of it reported by
Curist’ (p. 325) as growing near.a waterfall as. Montreux, or in
the damp forests of Portugal (see also ScHIMPER 1888, p. 31).
On ‘the contrary, the trees bearing this fern in Maryland were
near the top of’a northward facing cliff, more than 100 feet above
a small stream, and at the western end of a ravine which is about
125 yards wide at this level. Two dozen or more plants of this
fern were found growing in the deep furrowed bark of six different
chestnut‘ oaks (Quercus Prinus). |The clumps of polypody were at
various heights’ up to 20 feet or more above the ground. Clumps
of all sizes were found, showing that they had started on the tree
from prothallia, and had not:arisen from rhizomes that had climbed
upward from'the soil. With one exception they were all on the
north side (between N.N.E. and N.N.W.) of single erect trunks.

* Botanical contribution from the Johns Hopkins University, no. 70.

?Scummperr, A. F. W., Die epiphytische vegetation Amerikas. 1888.

3 Curist, H., Geographie der Farne. 1910.

237) : [Botanical Gazette, vol. 72

238 BOTANICAL GAZETTE [OCTOBER

The exceptional case was that of a set of several clumps on a tree
which had two trunks from a point about 5 feet above the ground.

F of Quercus Prinus (between 2 feet and 6 feet
above soil) awe several denis of Polypodium vulgare established as epiphytes on
the bark; cards 25 inches in size; #4.

1921] JOHNSON—POLY PODIUM 239

The two forks of the trunk stood almost in a north and south line,
and the crotch between them in an east and west direction. The
larger clump of polypody, which bore more than forty full grown
leaves, grew just below the fork on the east side of the tree (fig. 1).
At 6 inches and at 2 feet below this, on the same side, were two
smaller tufts of this fern (fig. 1). Both the latter evidently profited
from the collection of considerable water by the fork above, part
of which water was directed down the shallow grooves of the bark
in which these two clumps grew. This somewhat more abundant
water supply, which is likewise more constant, probably explains
_ the presence of these tufts on the east side of the tree, while all
the other clumps of this polypody seen were confined to the north
sides of the trees. The other five trees on which this fern was
growing had trunks that were perfectly straight and without forks
or any branches for many feet above the ferns (fig. 3). There was
thus no collection of rain, as in the forked trunk, but each clump of
polypody was dependent entirely on the portion of water that
chanced to run down the particular furrow in which it grew. The
fronds of the polypody on the unbranched trunks, although barely
half as large as those on the forked trunk, were quite mature, and
many of them bore spores. The more favorable growing conditions
on the forked tree were indicated not only by the larger size of the
polypody itself, but also by the richer growth of bryophytes and
lichens, which were much more abundant below the fork ee above
it on this tree, or than on any of the erect trunks (fig.

Aside from the smaller fronds of the epiphytic apie they
apparently were not different from those growing on the soil.
In both the rhizome was largely covered by epiphytic liverworts
and lichens and sometimes by more or less humus. The external
character and internal structure of the rhizome and of the leaf, even
to the thickness of the cuticle and of the mesophyll of the latter,
were quite alike in plants of both habitats. The roots of both
epiphytic and terrestrial plants were abundant, closely matted, and
thickly beset with root hairs. Many of these root hairs had one
or more fungous hyphae running lengthwise through them. These
hyphae could often be seen entering at the tips of the root hairs.
Whether they have the function of mycorhizal fungi has not been
determined.

240 BOTANICAL GAZETTE [OCTOBER

FooD OF EPIPHYTES.—Not only the water, which was running
over the bark of the supporting tree, but also the indispensable
mineral foods dissolved in it, are absorbed by the roots of the
epiphytic fern. In the locality under discussion, as well as in the
wet tropical forests where epiphytes are most abundant, there can
be but minute traces of mineral dust from the forest covered soil

Fic. 2.—Several clumps of polypody from near x in fig. 1, showing epiphytic
lichens and liverworts, fruiting fronds of fern above, and young plants developed
from prothallia below x at left; «3.

blown by winds to the tree tops, to be washed down over the trunks
by rains. It is evident, therefore, that the air plant is really de-
pendent on the tree not only for support, in an advantageous posi-
tion for light, but it must also rely on the tree to raise from the
soil the food salts needed. In other words, the mineral-containing
substances, resulting from the disintegration of bark, twigs, and
leaves of the supporting tree (or perhaps a neighboring one), and

1921] JOHNSON—POLY PODIUM 241

which are then washed down to the epiphyte, must first be carried
above the epiphyte by the water vessels inside the tree. The
epiphyte is to this extent dependent on a physiological process of
the living host, the upward conduction of water, which involves a
considerable expenditure of energy. The mineral food demands
made upon the tree by the epiphyte are thus somewhat equivalent
to those made by the “half-parasite” of its host. The chief
difference is that the mistletoe exacts its quota of salts (and of
water also) from within the living host, before they have been

Fic. 3.—Trunk of pane Prinus bearing at x and y (north side of ee two tufts
of P, oh vulgare; upper tuft 9 feet above soil, others above this are 18 or 20
feet from ground; Xs.

used by the host itself, while the air plant gets its salts from the
surface of the tree after they have served their function within it.
The water obtained by the epiphyte of course has never been
inside the supporting tree. If the mistletoe is to be called a “water
(and salts) parasite,’ the epiphyte is a “‘salts saprophyte”; that
is, it secures its mineral food from the dead and no longer functional
portion of the supporting plant.

ORIGIN OF TEMPERATE ZONE EPIPHYTES.—SCHIMPER (1888)
announced the very important generalization that the vast majority
of all vascular epiphytes are of tropical origin. Of extratropical
epiphytes he believed that only the relatively few types found in

242 BOTANICAL GAZETTE [OcTOBER

the rain forests of southern Chile and of New Zealand, with perhaps
a couple of epiphyte ferns in Japan and southern Australia, are
indigenous in origin. The other temperate zone epiphytes of the
Old World, of South America, and according to SCHIMPER all,
epiphytes of temperate North America, have acquired this habit
while in the tropical forest. ScHIMPER stated that it is the most
xerophytic of the tropical epiphytes, those growing on the branches
of the relatively dry roof of the forest, that have wandered out
across the neighboring savannas and subtropical forest and onward
sometimes 10 or 15 degrees beyond the tropics to populate with
epiphytes the warmer and moister of the neighboring temperate
forests. Because of the adaptation of these epiphytes to the dry
conditions at the top of the forest, they have been able, in spite of
the still more rigorous conditions encountered there, to colonize
certain temperate forests. For the epiphyte that migrates from
the tropics to the temperate zone, probably the most critical
adverse condition encountered is not the occasional hot, dry summer,
but the periods of low humidity during the generally wet winter
season, when cold, dry, northwesterly winds prevail, during which
the evaporation rate is high and water cannot be absorbed by the
frozen roots. For example, the writer has noticed that tufts of
Tillandsia usneoides, hung on a deciduous magnolia tree each year
in May, thrive and grow rapidly during the summer, and even
look fresh and green after several frosts in the autumn. They
ultimately succumb, however, to the cold dry westerlies of winter,
even of so moderate a winter as that of 1920-21. The precise
measurement of the evaporating power of the air at these low
temperatures, a factor of prime importance also to terrestrial
plants, especially evergreen ones, must await the invention of a
practicable frost-proof evaporimeter. Possibly the exposure of the
epiphyte to sunlight, when the supporting tree is bare of leaves, is
directly injurious also, although this seems hardly likely, since this
same Tillandsta is abundant on deciduous trees only 200 miles
south of Baltimore, where the winter sunlight would probably be
at least as strong. The sunlight of course must work harm
indirectly by increasing transpiration, which probably explains
the usual restriction of polypody to the north sides of the trees.

1925] JOHNSON—POLY PODIUM 243

The epiphytic ferns and seed plants of temperate North America,
such as Polypodium polypodioides, P. aureum, Vittaria lineata,
Psilotum triquetrum Sw. (=P. nudum [L.| Griseb.), Tillandsia
usneoides, and Epidendrum conopseum, and the eighteen others
named by ScHIMPER, have each a more or less widespread distribu-
tion in the American tropics, from whence they have probably
migrated northward. The occurrence of Polypodium vulgare as
an epiphyte in temperate North America, therefore, has a very
interesting bearing on this question of the possible origin of extra-
tropical epiphytes. For this fern, although distributed across the
whole north temperate zone, in the New World from western Canada
to Maine and south to Missouri and Georgia, and from Great
Britain to Japan and southward into Northern Africa, is not known
in the tropics, neither have fossils of it as yet been found there.
We have no adequate evidence, therefore, that Polypodium vulgare
acquired in the tropics the epiphytic habit which it assumes
occasionally in Maryland, and more frequently in the damp forests
of Portugal and Azores (SCHIMPER, 1888; CHRIST, 1910). The
occurrence of this fern (or a closely similar polypody) in Cape
Colony suggests that it may have crossed the equator by land,
but of this there is no positive evidence, and this view seems
negatived by the lack of fossils in equatorial Africa, and also by
the absence of this polypody at the present day from the temperate
highlands of the eastern tropics. From what is known of the
habitats of Polypodium vulgare it seems most probable that this
species is primarily a terrestrial plant of temperate forests. It
probably entered North America from Eurasia via Alaska, and
thence spread southward and eastward. It has acquired great
hardiness while living on dry rocky ledges, often with a very scant
water supply, and with no more soil than can collect in a few minute
cracks of the rock. Thus this temperate zone polypody has come
to be able to persist also in some shaded situations, on the very
precarious supply of water and minerals to be found on the trunk of
a rough barked tree. This is clearly true in spite of SCHIMPER’S
somewhat too positive statement (1888, p. 152) that “in the less
damp North American forests the first step, the migration of the
terrestrial plants to the trees, is impossible, and herewith the origin

244 BOTANICAL GAZETTE [OCTOBER

of an indigenous epiphytic association is excluded from the begin-
ning.” This Polypodium seems evidently an endemic epiphyte of
the temperate zone, and not one imported with this habit already
formed from the tropics. It might well be designated a facultative
epiphyte. In its ability to live on various substrata it closely
resembles dozens of species of ferns and seed plants of the tropical
forests which can be found growing, now on soil, now on dry rocks,
and again as epiphytes on tree trunks.

It might perhaps be suggested that more of our temperate
zone plants should prove able to live on trees. As a matter of
fact, however, few of our saxicolous vascular plants are really as
hardy as this polypody, the thick-cuticled leaves of which are
capable of rolling up in dry weather and so of lessening transpira-
tion. The combination of these two features, uncommon in plants
of this region but common in epiphytic ferns of the tropics, is
probably an important:one in'enabling this fern, and likewise its
relative Polypodium polypodioides, to adopt the epiphytic habit.
The evergreen leaves of Polypodium vulgare, which are also char-
acteristic of most, although not of all epiphytes,:are probably of
great importance to this plant of shady deciduous forests. They
enable it to carry on an important share of its photosynthetic
work on any mild days between October and May, when abundant
light reaches it because the surrounding trees are bare of leaves.
In other words, while growing on soil or rocks this fern has developed
more of these xerophytic characters, which fit it for living.as an
epiphyte, than perhaps any other vascular plant of the north-
eastern United States. It seems at the present time to be an
indigenous temperate-zone epiphyte in the making.

Jouns Hopkins UNIVERSITY

BALTIMORE, Mp.

CHROMOSOMES OF CONOCEPHALUM CONICUM

Amos M. SHOWALTER
(WITH PLATES IV, V)

The discovery of visible chromosome differences between the
sexes in many animals has led to a very wide acceptance of the
hypothesis that sex in animals is determined by the presence or
absence of certain chromosomes. This discovery has stimulated
botanists also to search for sex determinants, and experimental
work has apparently demonstrated that in Sphaerocarpos and
Thallocarpus two of the four spores formed by the division of a
spore mother cell produce male plants and the other two female
plants. In several dioecious mosses also experimental results
indicate that the sex potentialities are probably separated in the
reduction divisions. As yet, however, a visible chromosome differ-
ence between the sexes has been found in only two species of plants,
Sphaerocarpos Donnellii reported by ALLEN,’ and S. texanus
reported by Miss SCHACKE.

The present study of the chromosomes of Conocephalum coni-
cum (L.) Dum. was begun primarily for the purpose of determi-
ning whether or not there exists a visible difference between the
chromosomes of the two sexes in this species. The results in
regard to this question are totally negative, but the chromosome
number is found to be nine instead of eight, as reported by previous
workers for the gametophytes of this species.

The material used in the greater part of the study was grown
in the greenhouse in two separate cultures of male and female
plants respectively. These cultures were started with thalli bear-
ing old gametophores of the previous season’s growth, collected

* Arren, C. E., A cl diff lated with sex difference in S phaero-
carpos. Science, N. S. 46:466-467. 1917.
, The basis of sex inheritance in Sphaerocarpos. Proc. Amer. Phil. Soc.
58: 289-316. 1910.
2 Scuacke, M. A., A chromosome difference between the sexes of Sphaerocar pos
texanus. Science, N.S. 49:218. 1919.
245] [Botanical Gazette, vol. 72

246 BOTANICAL GAZETTE [OCTOBER

November 8, 1919, in Parfrey’s Glen near Merrimac, Wisconsin.
The archegoniophores were removed to prevent the possibility of
the development of male sporelings from the sporogones, which
latter were well developed at that time. The plants grew rapidly,
and apical tips of the plants of the two sexes were fixed at several
different times during the latter half of December. A few almost
mature antheridiophores fixed in the field and imbedded in paraffin
were obtained from Dr. W. N. Stet. In addition to this material
Dr. ALFRED GUNDERSEN and Professor A. F. BLAKESLEE generously
supplied living plants from stock received from Copenhagen, and
Professor A. J. EAmEs sent plants from Cascadilla Ravine, Ithaca,
New York. Comparative studies were made on these plants, but
all figures shown were drawn from the Wisconsin material.

Flemming’s medium solution with 4 per cent of urea added was
used jn fixing. Paraffin sections 4-6 » thick in the case of the
apical tips and 3 p thick in the case of the antherids were stained
with Flemming’s triple combination. The sections on a few slides
were restained in Heidenhain’s haematoxylin, but gave results
less satisfactory than those obtained with the triple stain.

The resting nuclei and stages in the formation of the spirem
were not examined critically in this study. Numerous nuclei in
spirem stages and in equatorial plate stages were found in these
preparations, but very few cases of spirem segmented into chromo-
somes not yet drawn into the equatorial zone of the spindle were
seen. Evidently, as observed by Farmer,’ the transition from
the unsegmented spirem stage to the equatorial plate stage is very
rapid, if indeed the migration toward the equatorial region does
not begin before the segmentation of the spirem, as evidenced
by the frequently observed tendency of the chromosomes to lie end
to end in the equatorial plate (figs. 2, 3,9). The limited number of
observations, however, does not justify any conclusion on this point.

Judging by the large number of nuclei in the equatorial plate
stage, a considerable pause in the movement of the chromosomes
occurs at this point, which also coincides with FARMER’s observa-
tions. The longitudinal splitting of the chromosomes does not

3 FARMER, J. B., On spore formation and nuclear division in the Hepaticae. Ann.
Botany 9:469-523. 1895.

1921} SHOW ALTER—CHROMOSOM ES 247

become apparent until very late; in fact, it is perceptible only
when the separation of the daughter chromosomes has actually
begun (figs. 13-15). The chromosomes are in the form of bent,
crinkly rods of varying lengths (figs. 1-11). The crinkliness is
less apparent in the late metaphases and in the anaphases when
the chromosomes are drawn out into smooth rods (figs. 12, 16, 19).
As observed by Escoyez,‘ they occupy a very definite plane in the
equatorial plate stage; in polar view they are easily counted at
this time, but in lateral view they appear as tangled masses
(figs. 8, 14, 15). Only one case (fig. 11) was found of an equatorial
plate stage in which the individual chromosomes could be traced
with any degree of certainty in a lateral view, and a very few such
cases in anaphases (figs. 12, 16, 19). The chromosome number is
plainly nine in either sex (figs. 1, 2, 4, 9, and 18 female; figs. 3, 5,
6, 8, and 1o male), one of the chromosomes being very small.
This small chromosome shows no constant difference in behavior
from the other chromosomes, either as to its position on the spindle
or in its time of division. In one case (fig. 15) it was found to
have been divided earlier than the other chromosomes, and in
another case it was found undivided in the equator of the spindles
when the other chromosomes were in anaphase (fig. 19). Meta-
phases and anaphases in which the individual chromosomes are
distinguishable are very rarely found, but if the small chromosome
constantly led the way in division, as it appears to do in fig. 15,
or if it constantly lagged, as seems to be the case in fig. 19, it should
usually be visible in the metaphases and anaphases, even though
the other chromosomes are not distinguishable one from another.
Apparently the small chromosome ordinarily divides at about the
same time as the other chromosomes, and in lateral view is dis-
tinguishable from them only in rare cases (figs. 12, 15, 16).

In cells of the apical tip of the thallus (of either sex) in which
the chromosomes are commonly spread out so as to make accurate
counts possible, the small chromosome is visible in about 80 per
cent of the cases counted; but in the antherid, where the cells are
much smaller and the chromosomes generally more closely grouped,

4Escoyez, E., Blepharoplaste et centrosome dans le Marchantia polymorpha.
La Cellule 24:247-256. 1907.

248 BOTANICAL GAZETTE [ocroBER

it is visible in a much smaller percentage of the cases. Consider-
ing the size of this chromosome, it is to be expected that in some
cases it should be obscured from vision by the other chromosomes
(figs. 7, 8, 14, 17).

FARMER, BOLLETER,’ EscovEz, and Woopsurn’® report eight
chromosomes in the haploid nucleus, and in my preliminary note?
J suggested the possibility of a variation as to chromosome number
in this species. More recent studies in plants from Ithaca and
from Copenhagen make it seem quite certain that the same number
of chromosomes is to be found in the plants of this species in those
regions. It seems probable, therefore, that these investigators have
overlooked the small chromosome, a thing which might easily
have happened, especially since they were interested primarily in
other phenomena.

A comparison of the chromosomes -of one sex with those of the -
other shows no perceptible difference, either in the number or size
relations, as may be seen by comparing figs. 1, 2, 4, 7, 9, and 18
(female) with figs. 3, 5, 6, 8, and 10 (male). Although this condi-
tion of like chromosomes in the two sexes in Conocephalum is not
an evidence against the sex chromosome basis of sex inheritance
in the dioecious Bryophyta, it does show that the marked differ-
ence between the chromosomes of the two sexes in Sphaerocar pos
is not a universal condition among these plants.

Summary

1. The chromosome number in the gametophyte of Cono-
cephalum conicum (L.) Dum. is nine instead of eight as reported
by previous investigators.

2. The chromosomes vary considerably in size, one being very
much smaller than any of the other eight.

3. There is no perceptible difference between the chromosomes

‘of £6 male and those of the female plant.

5 BoLteter, E., Fegatella conica, eine morphologisch-physiologische Monographie.
Beih. Bot. Centralbl. 18:327-408. 1905.

6 WoopspuRN, W. L., Spermatogenesis in certain Hepaticae. Ann. Botany
252299-313. 1911

seca, A. M., The Socios of Concephalum conicum. Science,
N. S. 532333. 1921.

BOTANICAL GAZETTE, LXXII PLATE IV

SHOWALTER on CONOCEPHALUM

BOTANICAL GAZETTE, LXXII PLATE V

SHOWALTER on CONOCEPHALUM

1921] SHOW ALTER—CHROMOSOMES 249

4. The plants received from Ithaca and Copenhagen show the
same number and size relations of the chromosomes as do the
Wisconsin plants.

I wish to acknowledge my indebtedness and gratitude to
Professor C. E. ALLEN, at whose suggestion and under whose
direction this study has been made.

UNIVERSITY OF WISCONSIN

EXPLANATION OF PLATES IV, V

All drawings were made with the aid of a camera lucida at a magnification
of about 3800, using a Zeiss 2mm. apochromatic objective N. A. 1.40 and
compensating ocular no. 18 with a tube length of 160 mm.

IGS. 1-11.—Equatorial plate stages in polar view (some slightly eae
except fig. 11 and one cell in fig. 8, which are in lateral view; symbol followi
number indicates sex in each case; fig. 1 from cell of dorsal surface layer near
apical cell; figs. 3-6 from cells of ventral surface layer; in fig. 4 one chromo-
some at left upper focus cut in sectioning; figs. 7, 10, and 11 from cells of
interior of thallus; fig. 8, group of six cells in antherid; fig. 9, cell of young
scale.

Fic. 12.—Anaphase in cell of air chamber wall, small chromosome being
visible in upper group o:

IG. 13.—Early m ehipliase in cell of ventral surface layer, in slightly
oblique (nearly polar) view; one chromosome, except tip of one end, in adjacent
section shown in fig. 13a.

IGS. 14, 14a.—Early hotaphases in cell of interior of thallus, cut in section-
ing; mer Rae not all distinctly recognizable.

Fic. 15.—Early metaphase in cell of scale, showing small chromosome
already divided, other chromosomes not individually distinguishable.

Fic. 16.—Early anaphase in cell at juncture of scale and main body of

IGS. 17, 18.—Anaphase daughter groups in successive sections of same
cell, seventeen in polar ven, eighteen in equatorial view; cell in floor of young
air chamber.

1G. 19.—Early anaphase in cell of ventral surface layer; small chromo-
some not yet divided.

PEACH YELLOWS AND LITTLE PEACH?
MEL 1 COOK

(WITH PLATES VI, V1)

Peach yellows and little peach are well known but poorly under-
stood diseases, and have been the subject of study by many workers
for a number of years. Although they have engaged the efforts
of some of our most efficient workers, the causes are as yet unknown,
the symptoms not well defined from similar symptoms due to some
other common causes, and the methods of control are very unsatis-
factory. Although the researches have been directed along many
lines, very little attention has been given to the morphology of the
organs of the infected plants as compared with the morphology of
corresponding organs on healthy trees. The fact that a knowledge
of the morphology is frequently a very important factor for physio-
logical studies has led to the preparation of this paper, hoping
that the accumulation of data along various lines may eventually
assist some student to solve this problem.

The material used was taken from trees in an experimental
orchard at Vineland, New Jersey, which was planted and managed
by the Department of Horticulture of the New Jersey Agricultural
Experimental Station. The trees were under constant observation,
and there was no doubt as to their condition. The material was
carefully collected during the early morning and mid-afternoon of
a bright warm day in midsummer, when the conditions were
exceptionally favorable for growth. Care was taken to select
leaves of approximately the same age, and the same precaution
was taken with the twigs. A great many sections were cut and a
considerable number of drawings made, from which the figures
shown in the plates were selected.

The studies were based on a comparison of the structure of
corresponding parts, the relative amounts of starch in these organs
morning and afternoon, and its relative location. The studies of

*Paper no. 29 of the Journal Series, New Jersey Agricultural Experiment
Station, hoes of Plant Pathology.

Botanical Gazette, vol. 72] [250

1921] COOK—PEACH YELLOWS AND LITTLE PEACH 251

structure did not show any differences of importance, and will not
receive further consideration at this time. The study, however, of
the amount and location of the starch within the tissues of the
leaves and green shoots gave some interesting data, and therefore
the basis of the work is a comparative study of the results of
photosynthesis and translocation of fob a Gangs in healthy and .
diseased trees.

Before considering this phase of the hak the generally recog-
nized symptoms of these diseases are indicated, since they must be
referred to from time to time. The first symptom in both cases is
an infolding along the midrib or rolling of the margins, accompanied
by a pronounced backward curving from base to tip so as to give
&, Sickle or crescent effect, and the development of a decidedly
leathery texture which is very apparent to the touch. The second
symptom for yellows is the development of enlarged, prematurely
ripened fruits, which show a characteristic red spotting or blotching
over the surface and through the flesh, especially prominent near
the stone. The final stage in the yellows is the development of
fascicled, willowy shoots. Very similar symptoms may be pro-
duced by partial or complete girdling of trunk or branch by winter
injury at the collar, by borers, by label wires, or other factors.
There is no doubt that many of the reported cases of peach yellows
in the past were in reality cases in which the symptoms were
produced by some of these causes. ‘The first stage or leaf characters
in little peach is similar to that of yellows, but is very likely to be
more pronounced than in yellows. In the second stage the fruit
is small and ripens later than in the normal healthy trees. There
is no willowy growth as in the case of yellows. The symptoms
just described are subject to many variations, dependent upon
cultivation, care, and other factors. Yellow foliage may be due
to many other causes, and is not necessarily a symptom of yellows,
In fact, trees infected with this disease may be very green, especially
if fed with a fertilizer high in nitrogen. Trees infected with yellows
will sometimes persist for a number of years, but those infected
with little peach usually die in a comparatively short time.

In a normal healthy plant the starch content is expected to be
much greater in the afternoon than in the early morning, due to

252 BOTANICAL GAZETTE : [ocTOBER

the high photosynthetic activity during the day and the lack of
photosynthesis and a very active translocation of starch during
the hours of darkness. In this work a study of the sections of
leaves from healthy trees removed early in the morning and in
mid-afternoon was made for comparison with leaves from diseased
trees which were collected at the same time. In the leaves from
normal healthy trees it was found that there was very little or no
starch in the leaves during the morning hours, and an abundance
during the afternoon (figs. 1, 2.) This of course was to be expected,
and indicated that the photosynthetic and translocation processes
were normal and active on the day that the material was collected.
In some instances a small amount of starch was found in the cells
in the morning in the immediate vicinity of the veins (figs. 3, 4).

This was no doubt due to incomplete translocation and may possibly
indicate a slightly abnormal condition.

Leaves were collected from the varieties known as Samay; Hiley,
and Chinese cling, which were affected with yellows. In those in
which the disease was severe, the amount of starch in the sections
from leaves cut in the morning was almost as great'as the amount
found in leaves cut in the afternoon, indicating little or no trans-
location of the carbohydrates (figs. 5, 6). The amount of starch,
however, was not as great in either case as in the healthy Elberta
(fig. 2) in the afternoon, but was greater than in the healthy Hiley
(fig. 4). These differences in the amount of starch in the individual
trees may be due to a difference in the physiological activities of
the trees, and may possibly be accounted for by differences in
variety, age, or other factors. .

A morning section of a Chinese cling affected with yellows (fig. 7) _
compared with a morning section of a healthy tree of the same
variety showed a much larger amount of starch in the leaf from
the diseased tree than in the leaf from the healthy tree, indicating
not only a reduced translocation of carbohydrates but also an
accumulation of these products. There was very little difference,
however, between the amount of carbohydrates found in the
morning and afternoon sections from diseased trees (figs. 7, 8).

The little peach was studied on Elberta and Hiley. The
amount of starch was practically the same in the sections from

tg2t] COOK—PEACH YELLOWS AND LITTLE PEACH 253

leaves collected in the morning as in the afternoon (figs. 9, 10),
but was less than in the trees affected with yellows (figs. 5,6). In
some other sections, however, the amount of carbohydrates in both
morning and afternoon sections was greater than that shown in
figs. 9 and 10. The starch in the sections from leaves cut in the
morning was most abundant in the central part of the leaf (fig. 9),
and may indicate some translocation. A morning section of leaf
from Elberta infected with little peach (fig. 11) showed a large
amount of starch, indicating that very little translocation of starch
had taken place during the preceding night. .

Pieces of new growth shoots were collected at the same time that
the leaves and sections from Elberta, Stump, Hiley, and Chinese
cling were studied. The results were practically the same through-
out, but as the material from the Hiley was most abundant and most
satisfactory it is used for this part of the discussion. A comparison
of morning and afternoon sections of young shoots from a healthy
tree shows a considerable amount of starch in the inner layers of
cortex in the afternoon section (fig. 13) and very little in the morning
section (fig. 12), indicating normal translocation of carbohydrates.
These twigs were from the same tree as the leaves in figs. 3 and 4.
The shoot from the tree affected with yellows (figs. 14, 15) was
slightly older than the healthy shoot. The amount in the morning
and afternoon was practically the same, indicating that there was
little or no translocation of carbohydrates. These twigs were from
the same tree as the leaves shown in figs. 5 and 6. The sections
from the tree affected with little peach showed a slightly smaller
amount of starch in the morning (fig. 16) than in the afternoon
(fig. 17), which may possibly indicate that there was a small amount
of translocation. These twigs were from the same tree as the
leaves in figs. 9 and ro.

It will readily be seen that all these studies on both the leaves
and the new growths indicate that the translocation of starch is
partly or completely inhibited in the diseased trees, probably
dependent upon the severity of the disease. This is indicated by
the large amount of starch present in leaves and green twigs from
diseased trees in the early morning, as compared with the relatively
small amounts in leaves and green twigs from healthy trees at the

254 BOTANICAL GAZETTE [OCTOBER

same hour. It is very generally recognized that girdling interferes
with the translocation of carbohydrates, and as a result thereof
bearing plants very frequently produce extra large fruits which
usually ripen prematurely. The production of large premature
fruits is also a characteristic symptom of yellows, and it therefore
appears that the physiological behavior of a tree affected with
yellows is the same or very similar (so far as photosynthesis and
translocation of carbohydrates are concerned) as in a tree that
has been girdled. In trees affected with little peach, however,
the symptoms, so far as the fruit is concerned, are just the reverse,
the fruit being somewhat smaller and ripening later than normally.
This may possibly account for the fact that sections of twigs from
trees affected with little peach showed some evidence of trans-
location of starch, while those from trees affected with yellows did
not show any such evidence. These differences, however, may
have been due to other causes, such as severity of infection, age of
trees, or other factors.

The preceding discussion indicates that the translocation of
starch is greatly reduced, possibly completely checked, in trees
affected with either of these diseases; or that have been girdled
and injured by label wires, bores, or at the collar as a result of
freezing. In all cases the results are an accumulation of starch
in the leaves, which may account for the leathery texture, but does
not offer an explanation of the willowy growth of the final stage
of the yellows. If the translocation of carbohydrates is reduced
or prevented, however, it may have a secondary effect on the
tree, resulting in the willowy growth.

Furthermore, the reduction or inhibition of the translocation of
carbohydrates may also account for the enlarged premature fruit
which is characteristic of trees affected with yellows, or that have
been girdled, but it does not explain the undersized fruit and
delayed ripening which is characteristic of trees affected with
little peach. These facts indicate that some of the symptoms of
these diseases are due to reduced or inhibited translocation of
carbohydrates. The cause of this condition is a question that
remains unanswered.

PLATE VI

BOTANICAL GAZETTE, LXXII

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PLATE

BOTANICAL GAZETTE, LXXII

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COOK on PEACH DIS

1921] COOK—PEACH YELLOWS AND LITTLE PEACH 255

The writer is indebted to Professor M. A. BLAKE and Mr.
Cuas. H. Connors of the New Jersey Agricultural Experiment
Station, for advice and assistance; and to Miss GERTRUDE E.
MAcpPHERSON for cutting the sections and doing most of the work
on the drawings.

RUTGERS COLLEGE
NEw Brunswick, N.J.

EXPLANAT ION OF PLATES VI, VII

Fic. -1 —Normal lest of Elberta a taken early in morning.
Fic. 2.—Same taken in afternoon.

Fic. 3.—Normal leaf of Hiley Felon taken in morning.

Fic. 4.—Same taken in afternoon.

Fic. 5.—Leaf of Hiley with yellows taken in morning.

Fic. 6.—Same taken in afternoon.

Fic. 7.—Leaf of Chinese eat oes yellows, taken in morning.
Frc. 8.—Same taken in aftern

Fic. 9.—Leaf of Hiley with little le peach taken in morning.

Frc. 10.—Same taken in afternoon.

Fic. 11.—Leaf of Elberta with litle peach taken in morning.

Fic. 12.—Section of twig of normal Hiley taken in morning.

Fic. 13.—Same taken in afternoon.

Fic. 14.—Section of twig of wash with yellows taken in morning.
Fic. 15.—Same taken in afternoo

Fic. 16.—Section of twig from Hiley with little peach taken in a
Fic. 17.—Same taken in afternoon.

EFFECT OF LOCATION OF SEED UPON GERMINATION
EDWARD N,. MuNNS

The influence of parent trees upon the size and germination of
Jeffrey pine seeds has been shown in a previous paper." The
marked results obtained from that work resulted in the present
study, in which it has been sought to determine the value of seeds
from different parts of the pine cone; and to decide what relation,
if any, exists between the position of the seed and germination.
The cones used were collected from Pinus Jeffreyi trees on the
eastern slope of the Sierras in Lassen County, California, in Sep-
tember 1919. No attempt was made to choose the trees from
which the cones were taken, except that the trees were young and
growing thriftily, considering the site upon which they stood.

The cones were grouped according to size in three divisions,
based on the gross characteristics of length, breadth, and weight.
They were dried slowly in a room at air temperature, and as they
opened the. seeds were extracted. The cones were divided into
three sections of approximately equal size, to be known as the
upper, middle, and lower portions. The seeds were carefully
collected and graded into three classes, large, medium, and small,
using ocular means of determining the size and comparing one
seed’ with another. Inasmuch as a number of individuals helped
’ to determine the size of the seed grains themselves, the individual
variation from this source was very largely eliminated. The seeds
were cleaned, counted, and weighed, each lot kept separately, and
sufficient seeds to carry out the test taken at random from each
lot. To determine the germination, a number of each lot of seeds
were sown in cans containing a uniform depth of soil and covered
by an approximately equal depth of sand in each case. As previ-
ous work has shown that for Jeffrey pine a soil moisture content
of about 15 per cent gives the best results, frequent weighings
were made to keep the moisture content of the samples a constant at
this figure. The result of this study is presented in tables I-VI.

tMunns, E. N., Effect of fertilization in seed of Jeffrey pine. Plant World
22:4. 1910.

Botanical Gazette, vol. 72] [256

1921]

MUNNS—GERMINATION

It was found that there was an increase in the number of seeds
with an increase in the size of the cones, medium cones having
27 per cent more seeds than the smaller ones, and the large cones

TABLE I
NUMBER AND WEIGHT OF SEED PER CONE
Num- Noir IGHT AVERAGE WEIGHT PER 100 SEEDS (GM.)
BER OF OF DE-
BER OF
WEIGHT| UNDE- | \eye,-| VEL-
SIZE OF VEL- OPED By portion of cone By size of seed re
OF cone | opep | OPEP | seeps, —
CONES (cm.) | seeps | SEE ie.
PE ER | CONE : Medi-
CONE | (gy) Upper | Middle | Lower | Large — Small | cone
Ey Use ees 228 60.6 62.0 |: §.33 | 8.47 | 8.75 | 8.49 | 20.33 Sat) 6.17 8.57
Medium......... 189.2.) 58.0 |: 51.6 }'.4.08 | 7.30 |. 8.92 1 -. 7.83 | -0.24-]-- 7.82 1 §.8r 7.78
a1 Rae ga gat 145 37.3°| 38.0) 2:66) G.aa | 7.78) 7.68:) 7.83 1 6.49 | 6:30 7.09
TABLE II 3
NUMBER OF SEEDS PER CONE BY SIZE OF SEED
LARGE CONES MEDIUM CONES SMALL CONES
SEEDS : ;
Upper —_ Lower} Total | Upper _ Lower] Total | Upper a Lower) Total
Undeveloped. ........| 28.7 | 22.2 | 18.7 69.6 | 25.5 | 16.9 | 15.9 | 58.3 | 13-0 | 14.5 |-19.7 | 47.2
ge eran oer nein ds 4:9 | 1079 9.6 | 2877 Og 6.9 1.8 i 13.6 I.5 2.0 1 37.9
PARURS Sey: 19.9 | 16,2 1 6.41) S89 7.8) Bet 6 Tay. 6.5 | 2.9 | 4.6] 4.0
PE eat 2.8 2.0 2:3 7.619. 0 1" 23 0.8) Bee ti S.6 1 8.6} 8.0). Bis
Total developed seeds 21.4 | 98.3 |.12.3 | 67:01 18:5 | 96.9 | 9.9] 52.61 25:7 7.41. 8.8 130.6
Total. 131.6 109.9 86
TABLE III
PERCENTAGE OF SEEDS IN CONE BY LOCATION IN CONE
LARGE CONES MEDIUM CONES SMALL CONES
SEEDS : -
Upper — Lower, Total | Upper — Lower} Total | Upper — Lower! Total
Undeveloped......... 41.2 | 31.9 | 26. oo | 43.7 | 29-0 | 27.3 | 100] 27.5 | 30.7 | 41-8} 100
ick Gia ieee inca 26.2 | 54.5 | 10.3 100 | 41.6 | 46.3 | 12. 106. 1-70.8)1..8.8 | 42.7 |. 100
Medium: <. 05000555 37.01 45.1 | 17.9 | 100 | 26.3 | 53.6 | 20.5 100 | 46.4 | 20.7 | 32.9 | rI00
“ages i tins Hoe Ue 43.4 | 26.3 | 30.3 | 100| 22.5 | $7.3 | 20.2 | 100 | 42.3 | 35.3 | 22.4 | 100
Total developed as 34-5 | 45-6 | 19.9 | 100] 30.0 | 52.2 | 17.8 | 100| 59.8 | 18.7 | 21-5 | 00

51 per cent more than the small cones. Another interesting thing
was that there were more undeveloped seeds than developed, except
in the case of the small cones, where there was a slight decrease.
In the large cones 47.1 per cent of the seeds were fully developed,

258

BOTANICAL GAZETTE

[OCTOBER

in the medium cones 47.0 per cent, and in the small cones 54.2 per

cent.

In each cone it was found that there were twice as many large

as small seeds, and more medium seeds than there were large and
small seeds together, except in the small cones where there was a
slight decrease.

The quantity of large seeds amounted to about 30 per cent of the
total in the large and medium sized cones, and 43 per cent in the

TABLE IV
PERCENTAGE OF SEEDS IN CONE BY DEVELOPMENT AND SIZE

LARGE CONES

MEDIUM CONES

SMALL CONES

Upper

_— Lower

Upper

Mid-

Aver-
dle Lower age

Mid- Aver-
dle Lower age

eloped .. i... cs.54.
Lpehens vee Pipe esas

Total

36.7
63.3

50.0
50.0

37.2

47.9
62.8 | 53.0

46.6
53-4

54.2
45-7

100.0

100.90

100.0

100.0 |100.0

34-5

TABLE V
WEIGHT OF SEEDS IN GRAMS PER 100 SEEDS
‘

SIZE OF SEED

LARGE CONES

MEDIUM CONES

SMALL CONES

Upper | Middle

Lower

Upper

Middle) Lower

Upper

Middle Lower

10.20 | 10.14

Large
Mectum

mall

8.47
5.92

8.15
6.41

ar.
e:
6.32

o7
84

8.33
60

small cones; medium seeds made more than 50 per cent of the
total in the large and medium cones, and 35 per cent in the small
cones; while the small seeds formed 12 to 17 per cent in the large
and medium cones, and 21 per cent in the small cones.

The weight of seeds ranged from 4.20 to 11.07 gm. per hundred
seeds, the average being 8.28 for large cones, 7.56 for medium
cones, and 6.85 for the smallest.
unity, the heaviest seeds in the small cones exceeded this by 135
per cent, the smallest in the medium cones was 14.5 per cent

Using the smallest seeds as

1921] MUNNS—GERMINATION _. 259

heavier, while the largest was 141.7 per cent. The lightest seeds
in the large cones exceeded the smallest seeds by 41 per cent, and
the largest seeds were 164 per cent heavier than the smallest seeds.

Table VI shows that it is the size of seed rather than position
in the cones which is the determining factor, there being a decided
decline in the germination per cent with the size, while apparently
no relation holds between position and germination. It has been
shown that the weight of the seed is directly influenced by the

TABLE VI
GERMINATION PER CENT BY SIZE OF SEED AND LOCATION
Material Large cones Medium cones Small cones Average
Deree Qeed 3) ic a 66.9 58.1 55-2 60.1
Medium seed............. 51.9 52.4 35-4 46.6
SOO rae es oy 35-2 25.5 23.7 28.1
Ripper cones esha. 51.0 38.6 35.8 41.8
Middle cones............. 52.9 50.7 “5 47.6
Rewer Cots oo oy 50.7 46.7 39-1 45-5
Average for cones... .. | Sis | 45-3 | 38.1 | 45.0
TABLE VII
GERMINATION PER CENT BY WEIGHT OF 100 SEEDS IN GRAMS
Weigh inati iy inati : Germinati
peat, | Srmimtim | wane | Cemmtin | wae | Ocmina
AO Sah 7.0 49.5 10.0 | 64.5
BO ace 24.5 8.0 48.5 it. 72-5
OO 9.0 56.5 12.0 |

size of cone, and this is further reflected in the germination. Chart-
ing the weight and germination, it was found that a straight line
relation existed, which is expressed in table VII. A curious rela-
tion was shown in the rapidity of germination. Seeds from the
lower portion of the cones completed half their germination five
days sooner than seeds from the middle third of the cone, which in
turn were five days earlier than seeds from the upper part of the
cone. Apparently this was independent of the size of the seeds
and varied with the size of the cone, the seeds from the larger
cone being the more rapid. Final germination apparently did not
conform to any regularity, except that the seeds from larger cones

260 “ BOTANICAL GAZETTE [OCTOBER

completed their germination first, followed by the medium sized
cone, the small cone seeds being last, with two weeks difference
between the large and small cones.

These results: have an immediate application in forestation
work. So far as is known, little attention is being paid to the
parentage or the condition of the seed before sowing. As pointed
out previously, only seeds from thrifty trees should be used, and in
the present study it appears that if it is impossible to collect
only the largest cones in the field, a screening process is necessary
to remove the small seeds and secure only those of large size.
Studies under way show a relationship between the size of seeds and
the early growth and establishment of forest tree seedlings similar
to that given here, and it is believed that the ‘‘dominance”’ classes
in the forest in a measure are an index of the size of the seed from
which the tree originated. To secure the best possible forest, it is
believed that forest nursery practice should be confined only to the
production of trees from the heaviest and therefore largest seed.

Forest SERVICE
Wasuincton, D.C.

CURRENT LITERATURE

BOOK REVIEWS
Diseases of economic plants
e appearance of a revised edition of STEVENS and HaAtt’s Diseases of
economic plants* will be welcomed by every one interested in plant pathology.
Since the publication of the first edition in 1910, so much progress has been
made in the rapidly expanding field of plant pathology that a revised edition
of this work will be appreciated, especially by the busy teacher and investigator.
The general plan of the book is similar to that of the first edition, although
some changes have been made. The first fourteen pages are devoted to a
brief summary of the history of plant pathology, the damage caused by plant
diseases, and methods of prevention or cure. General diseases, such as damp-
ing off, root rot, and soil diseases, are discussed in a special section of the book.
The diseases of special crops are grouped under the crop plants upon which
they occur, and a chapter on tropical diseases has been added. This is followed
by a chapter on fungicides and spraying apparatus, and another on soil disin-
fection. The bibliography contains 556 well chosen titles. Since the book
is intended primarily as a text for college students, according to the author,
many students, and certainly many teachers, will wish that the historical
summary were more detailed. One might wish also that the damage caused
by plant diseases had been discussed more fully. An account of the most
serious epidemics probably would have been especially appreciated. The
methods of disease prevention are grouped on the basis of more or less specific
operations, such as seed treatment, the use of protective sprays and dusts, the
selection of resistant varieties, and avoidance of practices which aid in the
dissemination of the parasite. A brief account of quarantines possibly might
have been desirable; and a more general grouping of control measures probably
would seem preferable to some pathologists. The discussion of specific diseases
is limited to essential facts. ‘The economic importance, signs, general etiology,
and control measures are given for all important diseases. The presentation
is as detailed as could be expected in a book of such wide scope, and the litera-
ture citations by the student to sources from which further information
may be obtain
5 hook | is an excellent compendium of practical facts regarding plant
decane and should be especially valuable as a reference. It is concisely
written, well illustrated, and contains an extensive bibliography. It is to be
hoped that the book will find its way into the hands not only of students,
teachers, and investigators, but also of farm bureau advisers and the more

* Stevens, F. L., and Hatt, J. G., Diseases of economic plants (revised edition
by 2,1. STEVENS). ‘pn. 507. Macmillan Co. 1921.

261

262 BOTANICAL GAZETTE [OcTOBER

intelligent growers. STEVENS has rendered a distinct service to phytopath-
ology by summarizing in a compact, neatly bound volume such a vast body
of knowledge in an increasingly important field of applied botany.—E. C.
STAKMAN.

A textbook of botany

Under the title General Botany, DENSMORE? has added to the already
numerous textbooks of elementary botany whose scope and content are suitable
for use in the junior college or normal school. The headings of the first two
and of the last chapter in the book, The relations of plants to the environment,
The form and adjustments of the plant body to the environment, and Plant
associations, show that ecology has been given due emphasis. The inter-

ning chapters are devoted to plant anatomy, physiology, and morphology
in a way that seems to fit the title of the book. There is even an attempt at
the beginnings of classification, with the consideration of representative species
and families from the spring flora. In a word, the material is sufficiently
comprehensive that in the hands of a good ae it will furnish the basis of
a good general introductory course in the subject.

There is evidence in the volume that it comes as a result of a wide expe-
rience in the laboratory and in the field. The illustrations are numerous, many
are original, and several, such as those of diagrammatic life histories, are of
more than usual merit. The addition of a glossary would have supplemented
the usefulness of the volume.—GeEo. D. FULLER

West African forests
A volume entitled ‘West African forests and forestry,” by Unwin,3 late

ere are also chapters on The oil bean seeds and nuts of the forest;
The oil palm and palm kernel industry; The forest in relation to agriculture;
and A bibliography of West African forests. Considerable space is also devoted
to the native names for the various trees.

e abundance and excellence of the photographs, together with the notes
on the general forest conditions, — oe ecologist and geographer with
gs data eae the a relatively unknown region.
e adequate and able to add to the usefulness of the volume,
but the pe puRE leaves much to be desired in the way of accuracy and
completeness of citations.—GeEo. D. FULLER.

2 Densmore, H. D., e8iri botany. 12mo, pp. xiit4s50. jigs. 289. Ginn
and Co., Boston. 1920.
, West Asan _— and forestry. 8mo. pp. 527. jigs. 110.
London: T. ue Unwin Ltd.

1921] CURRENT LITERATURE 263

NOTES. POR STUDENTS

Flora of southern Illinois.—In analyzing the elements reared into the
4 di

as a recent invasion, but as the remnants of a more numerous aggregation that
existed here in the remote past. These species, therefore, are not extending
but rather restricting their range. Two floristic formations are distinguish

they center. The former dominates the rich soils of the Mississippi and the
Ohio River flood plains formerly covered with rich forests. Among the common
tree species are Taxodium distichum, Nyssa aquatica, Gleditsia aquatica, Fraxinus
profunda, Liquidambar styraciflua, Quercus lyrata, Betula nigra, Carya laciniosa,
and many others. Among the herbaceous plants may be mentioned Hottonia
inflata, Triadentum petiolatum, Dianthera ovata, Spilanthes americana, and
Mikania scandens. The Mounds formation reaches its best development upon

densis, and Acer saccharum. Upon the lower elevations the trees are large and
tall, while upon the poorer soil and greater elevations of the Ozark hills not
only is there a decrease in size, but there is a greater predominance of oaks
and hickories, such as Quercus velutina, Q. alba, Q. stellata, Carya glabra, C.
ovalis, and C. alba.

The report concludes with a list of woody plants collected. This includes
not less than twelve species and varieties of Carya and fifteen species and
eight hybrids of Quercus.—Gro. D. FULLER.

Seasonal —- in corbohy Grates Mista! has recently published a
paper on apple seedlings. Analy-
sis has been made on one- and two-year old stems and roots and on fruit spurs,
for the determination of the amount of starch, sucrose, maltose, glucose, and
total sugars at intervals of fifteen days during the year. Some determinations
of acidity in autumn, winter, and spring have also been made. Starch reaches
its maximum amount in one- and two-year old apple stems in October an

November, with a secondary increase in June. The same is true of roots.
Total carbohydrates show a similar curve, reaching 44 per cent in winter.
Total and reducing sugars in one- and two-year old stems.and in roots increase
in January and March. The author finds an increase in acidity in November,

4 Pa , E. J., Botanical reconnoissance of southern Illinois. Jour. Arnold
Aiictae 3 a: a §3. 1921.

5 Mirra, S. K., Seasonal changes and translocation of carbohydrate aga in
fruit spurs and two-year old seedlings of apple. Ohio Jour. Sci. 21: 89-103. i

264 BOTANICAL GAZETTE [ocroBER

while the tissue is practically neutral in February and March. He states also

that there is a general correlation between acidity of tissues and the relative

activity of diastase and maltase as determined from amount of glucose and

maltose in tissues. _Maltose i is most abundant when acidity is high and near
s

the optimum for maltase activity. An average of eight determinations of
maltose made in November, when acidity is highest, is 1.99 per cent, and an
average of eight similar determinations made in March, when tissues are practi-
cally neutral, shows 1.86 per cent maltose. This difference seems too insignifi-
cant to conclude that maltose is present in larger quantities at a time when
acidity is highest, especially when maltose determinations vary from 0.46 to
3 or 4 per cent. e only conclusion concerning this, in the reviewer’s judg-
ment, is that maltose is always present and in very variable amounts.—JOHN
M. ARTHUR

Ecology of the Gangetic plain.—In a paper of more than usual interest,
DupceEon’ has included bbe results of his studies of a region whose ecology
has been almost unkno This part of India, lying immediately about
Allahabad, has a deceit whetodic: climate, with about 90 cm. of rainfall, and
three distinct seasons. The rainy season, from June to the end of September,
has high precipitation, high humidity, high temperature, and low insolation;
the cold season, from October to the end of February, has high humidity, high.
insolation, but low rainfall and low temperature ee 35° F. to ss’ F.); the
third or hot season, has Jow rainfall and humidity, but high insolation and
temperature (mean 80° F.).

The existing vegetation is shown to be influenced quite as much by the
biotic factors of a human population of 530 persons and 470 domestic grazing
animals per square mile as by the nature of the climate. Most of the area is
covered with dry meadow and thorn scrub, but it seems certain that these
associations, now balanced against intense human influence, are really the
retrogressive remains of a much richer climatic vegetation. The author seems
to have thoroughly established his final conclusion, that “if the retrogressive
influence of the biotic (human) factors were removed, the vegetation would
pass through the progressively higher forest stages of (1) fully developed thorn
scrub, (2) pioneer monsoon deciduous forest, and (3) climatic climax monsoon
deciduous forest, a forest of considerable density and luxuriance.’’ This forest,
as shown by adjacent regions, would show Terminalia tomentosa and Tectona
grandis as dominant, and would also contain Sterculia spp., Bombax
baricum, Anogeissus latifolia, Buchanania latifolia, Eugenia Janttolons, and
probably Acacia catchu and Shorea robusta. —Gro. D . Fu ‘

6 DupGEON, WINFIELD, A contribution to the ecology of the upper Gangetic
plain. Jour. "Ind: Bot. 1:1~29. figs. 9. 1920.

VOLUME LXXII NUMBER 5

LHE
HOTANICAE” (GAZETTE

NOVEMBER 1o2t

DECAY OF BRAZIL NUTS

EDWIN ROLLIN SPENCER
(WITH PLATES VIII-XII AND THREE FIGURES)
Introduction

Brazil nuts, Para nuts, Cream nuts, etc., are the seeds of
Bertholletia nobilis Miers and B. excelsa Humb. and Bonpl. The
nuts are harvested in the months of January, February, and March,
when the heavy pericarps containing the seeds fall to the ground.
They are collected and transported from the forests to the seaports
at a time of year when heat and moisture favor fungous growth,
and often a cargo reaches New York 30 per cent spoiled. The
United States Bureau of Chemistry holds that nuts are adulterated
food if more than 15 per cent are spoiled, and requires that such
nuts be shelled before being placed on the market. In spite of
these measures, however, Brazil nuts reach the consumer containing
from 10 to 25 per cent of spoiled nuts. There were 43,076,348
pounds of Brazil and Cream nuts shipped into the United States
in 1919 (7). It is probable that half of this amount, or 21,538,174
pounds, were retailed in the shell. It is conservative to estimate the
loss through spoiled nuts at ro per cent of this amount, or 2,153,817
pounds, an approximate money loss, at 40 cents per pound, of
$861,526.80, which falls directly upon the consumer. Brazil nuts
do not become rancid very readily, and for this reason they are
not placed in cold storage during warm weather as are most other
nuts. They are heaped in piles in supposedly dry and often very

265

266 BOTANICAL GAZETTE [NOVEMBER

-hot rooms. where, when moisture is present, fungous growth is
favored.

There is a wide difference in shell porosity of Brazil nuts, and
a positive correlation between fungous infection and shell porosity
has been demonstrated. Two two-pound samples of Brazil nuts
purchased at two different grocery stores were tested for porosity
of shell as follows. The nuts were taken one at a time and dipped
first in 95 per cent alcohol to prevent the collection of surface
bubbles, and then plunged two or more inches beneath the surface

TABLE I
VERY POROUS SLIGHTLY POROUS LEAST POROUS
‘ SPOILED
PERCENTAGE SPOILED
Cracked | Spoiled | Cracked | Spoiled | Cracked | Spoiled | SAMPLE
Sample I
166.75) or 4 BOM Ae Palas Cea bee wie Cleary AEs Te ee
Ge aie ia wk ya ae Cobia keke bom ae 6 26 Qo festa outs es hee eae
Ci tn es foci Meaty tice irs) bo iran rae Soman Bear aneurid Byitonnco a 49 Ben Ree
Bi Ae MUNN bs hs bas $s Oa «hey Ga SARS ek ee ct a 19
Sample IT
60 as 2 Dae cies es atl Ga ee Eee Ow
BN a tee fe ee 21 ig Penny ae ura Pape a
een) Enron) Rn Recon) Gene 7° ak ee
ETA OUI bo ei I, | Dead Aaa Mee me 14

of hot water contained in a tall beaker. The heat-expanded air
arose in bubbles from the pores of the shell. Table I shows the
results obtained. The conclusion to be drawn from these data is
that the most porous nuts are not necessarily spoiled, but readily
become infected when conditions favor infection, while the least
porous nuts are much less subject to infection. It is quite possible
that so long as the water content of the nut is sufficient to support
fungous growth, nuts with very porous shells may be entered and
spoiled if storage temperature is favorable. Such infections prob-
ably account for the high percentage of spoiled Brazil nuts bought
of retailers whose wholesale patrons have scrupulously complied
with the ruling of the Bureau of Chemistry when the nuts were
purchased at port.

1921] SPENCER—BRAZIL NUTS 267

Although the use of nuts as foods and confections has recently
become extended and general, there is but little concerning nut
diseases in the literature, and studies of the diseases affecting the
nuts only for the most part have been superficial. MANGIN (17)
described a “black rot” of chestnuts caused by Harziella castanae
Bain., and found it to cause a 26 per cent loss of nuts gathered late
in de season. VON IvANOFF (31), in studying Trichothecium
roseum Link, found it in pure state on the kernels of Corylus avellana
and Pinus cembra, and this, with RAND’s (23) work on Coniothyrium
caryogenium Rand, is the only serious investigation of nut parasites
that has been made. Marrz (18) reports a species of Cephalo-
thectum on pecans in Florida. Kuni (13) isolated Aspergillus
flavus Mont. from Brazil nuts, but his description of both disease
and fungus is meager.

A few parasites of nut plants cause diseases of the nuts them-
selves. The most serious disease of this kind is that produced by”
Pseudomonas juglandis Pierce, which, according to SmrrH (27),
attacks the nuts as well as other growing parts, and ‘‘a nut in
such cases is deformed in shape... . and the kernel .. . . is
only poorly developed.” Prerce (21) says that in young nuts
the kernel is destroyed. Chestnuts are affected by Endothia
parasitica (Murr.) A. and A. RuMBOLD (24) says that the hyphae
of this parasite spread throughout the kernel. The kernel spot of
pecan produced by Coniothyrium caryogenium Rand has incidently
been studied by TuRNER (30), and by RAnp (23). In addition to
these studies, there have been some reports on storage results
(6, 29), and McMurran (16) mentions what he considers a non-
parasitic disease, the “‘black-pit” of pecan.

The aim of the present investigation was to isolate and identify
as many as possible of the more important fungi and bacteria
causing deterioration of Brazil nuts. Seven distinct organisms
have been isolated, studied, and their etiological relation to the
nut deterioration demonstrated. The remainder of the paper com-
prises the methods of study and descriptions of the organisms
isolated.

Methods

The nuts studied were obtained from two wholesale firms in

Chicago and from retail grocery stores in Champaign and Urbana,

268 BOTANICAL GAZETTE [NOVEMBER

Illinois, and were purchased at different times during the year
1919-20. Each nut was superficially examined and the shell
carefully removed by cracking it with a hammer. The diseased
nuts were dropped, shell and all, into suitable sterilized glass dishes, *
one nut in each dish. A number was assigned to each, but only
those diseases which were most prevalent and which presented
the most conspicuous diagnostic features were selected for
study.

A preliminary examination was made of thin razor sections of
diseased tissue mounted in water or xylol, in order to discover
whether fungi or bacteria were present, and if so, to ascertain
their general relation to the host tissues. If this examination
showed any single species of organism to be predominant, isolations
were made either by direct transfer to cornmeal agar plates, or by
dilution plating as the case required. These isolations were from
both exterior and interior portions of the nut, and when from the
interior were carried out in the following manner. The nut meat
was cut into with a flamed scalpel and carefully broken apart.
A central portion of about 4 sq. mm. area was carefully removed
with a flamed scalpel from one of the newly exposed surfaces, and
discarded. In the center of the cavity thus made small pieces of
diseased tissue were loosened with the point of the scalpel, and
immediately carried in a sterilized loop to the surface of cornmeal
agar plates.

Following isolation, the next step was to determine whether
the fungi isolated were responsible for the various diseased condi-
tions. Two methods were used; first, pieces of mycelium or a
few spores were placed on sterile kernels contained in sterilized
one-inch test tubes;. and second, pieces of mycelium or a few
spores were placed upon strips of sterile nut meat, 50 uX5 X10 mm.,
which were contained in tubes of sterile water, one strip on the side
of the tube just above the surface of the water and the other in
the water. By the first of these methods the rotting power of the
parasite was made evident within a few weeks by the softening of
the whole mass. With the second method results were obtained
more quickly by more or less complete dissolution of the very thin
sections employed. The following media were used in the case
of every organism.

1921] SPENCER—BRAZIL NUTS 269

CORNMEAL AGAR.—This was prepared as recommended by
SHEAR (26), except that the medium ready for filtration was poured
into precipitation cones and autoclaved. After solidifying, the
precipitated dirt at the apex of the inverted cone was removed and
the clean agar melted and tubed.

BRAZIL NUT AGAR.—Fifty grams of Brazil nut kernels which
were free of, or easily freed from, their inner seed coats were
ground in a nut grinder (a Russwin no. 1 Food Cutter was used),
and steeped for one hour at from 58° to 60° C. in 1000 cc. of distilled
water, counterpoised, and filtered. Fifteen grams of powdered
or crude agar was added and the mixture boiled for ten minutes,
counterpoised, poured into precipitation cones, and autoclaved at
15 pounds for fifteen minutes. After solidification the agar was
removed from the glass cone and placed on a clean sheet of paper.
After removing the sediment the dirt-free agar was returned to the
precipitation cone and again autoclaved. The resolidified agar
cone was in two distinct layers, and the translucent layer was
the one used.

Nut pLucs.—It was found possible, by flaming a scalpel after
each stroke, to cut out nut plugs of considerable size which were
free from contamination. The kernels from which such plugs
were to be cut were placed in a 2 to tooo solution of ic chlorid
where they remained for thirty minutes. They were taken from
the solution one at a time, held by one end between thumb and
finger, and shaped by cutting away a thin layer with a sharp scalpel,
flamed after each stroke. When the plug was finished it was cut
off after placing it within the mouth of the reclining one-inch test
tube. Nut plugs made in this way remained uncontaminated for
several months.

Nut strips.—Strips of nut meat, 50 uX5X1omm., were cut
on a microtome and preserved in absolute alcohol. When used
they were taken from the alcohol with sterilized forceps and placed
in sterile water in a Petri dish. From this they were removed
with a sterilized loop and placed in test tubes containing sterile
water, as already described.

AUTOCLAVED RICE.—This medium was made by placing two
or three grams of rice and twice the volume of water in test tubes
and autoclaving.

270 BOTANICAL GAZETTE [NOVEMBER

MICROTOME SECTIONS.—These were made in order to show the
morbid histology in comparison with the normal histology.: Because
of the oil content of the nut, ether was found to be the best killing
and fixing agent. The ether was replaced after three days with
chloroform, and the ordinary schedule for imbedding with this
reagent followed (2). After sectioning it was found that the oil
content had not been sufficiently lessened, and that without its
removal a distinct view of the structures could not be secured. To
obviate the difficulty the sections were fixed to the slide, treated
with xylol, xylol and absolute alochol, absolute alcohol, and then
flooded four or five minutes with ether. The slide was held
horizontally between thumb and finger, and the dissolved fats
collected on the under side of the slide, from which they were wiped
off before placing the slide in 95 per cent alcohol. ‘The slide was
kept in each of the 95, 85, and 70 per cent alcohols for about five .
minutes, and then flooded with Pianese IIIb for 15 minutes (32),
washed with distilled water, 70, 85, and acidulated 95 per cent
alcohol, 95, 100 per cent alcohol, 100 per cent alcohol and xylol,
xylol, and mounted in balsam. The stain shows the host tissue
in red and the fungus in green.

Two of the fungi produced pycnidia which were sectioned for
study. These were taken from cultures on cornmeal agar, killed
and fixed with chromacetic fixing fluid, and stained with Bismark
brown, following the usual schedule for this stain. The pycnidia
were removed from the culture on a strip of agar, usually about
1 X2X4 mm. in size, which remained intact throughout the process
and served well in the orientation of the specimens in the imbedding
dish.

FREEHAND SECTIONS.—It was occasionally found necessary
to stain razor sections made for the preliminary study of the dis-
eased tissue. The sections were cut as thin as possible and placed
in a watch glass contained in a Petri dish. The watch glass was
then filled with ether and the Petri dish closed. When the ether
had evaporated, 95 per cent alcohol was poured over the sections and
allowed to stand for ten or fifteen minutes. This was followed
with 85, 70, and 50 per cent alcohols for five minutes each. The
_ sections were then transferred to slides prepared with albumen

1921] SPENCER—BRAZIL NUTS 271

fixative, flooded with water, and allowed to stand over night.
They were stained with Pianese IIIb, or with jod griin-erythrosin
in the following manner. They were placed in 95 per cent alcohol
for five minutes, flooded with jod griin (1 per cent solution in 95
per cent alcohol) for thirty minutes, washed with 95 per cent
alcohol, then absolute alcohol, flooded with 1 per cent solution of
erythrosin in clove oil for forty-five minutes, washed with absolute
alcohol, cleared with carbol-turpentine clearer, and finally washed
in xylol and mounted in balsam. This proved to be the most
satisfactory of any method tried for staining mycelium in the
tissue.

PROTEOLYTIC ENZYMES.—The Brazil nut agar serves well to
show the presence or absence of certain extracellular proteolytic
enzymes. The proteid precipitates to which the opacity of the
agar is due are digested by the enzymes, and a transparent halo,
which enlarges as the thallus or colony enlarges, surrounds the
growth. All the organisms studied were tested for the presence of
these enzymes. The enzymes were precipitated from cornmeal
broth in which an Actinomyces or a Bacillus, the two most active
enzyme producers, was grown. The broth was poured into Pior-
kowski culture flasks to a depth of 0.25 inch, about 200 cc. being
required for each flask, and inoculated. After ten days the culture
was filtered through paper and enough 95 per cent alcohol added
to the filtrate to make 80 per cent alcohol. Three days later a
fluffy white precipitate had collected at the bottom of the precipita-
tion cones, and the excess alcohol was siphoned off (12). From
25 to 5occ. of absolute alcohol was added to the precipitate and
immediately filtered. Before the precipitate had become dry
it was again washed with 50 cc. of absolute alcohol, and while still
moist was removed to a desiccator containing sulphuric acid, and
allowed to remain there for two days. The hard, gray material
_was then scraped from the paper to be redissolved in sterile water
when used.

MorpHOLoGcy oF Brazit NuT.—The kernel of the Brazil nut,
as it is ordinarily removed on cracking the shell, is covered with
a thin, dry coat which may be quite loose or may adhere very
tenaciously. The embryo within, principally radicle, is completely

272 BOTANICAL GAZETTE [NOVEMBER

enveloped with a layer of endosperm 4o to 50 uw in thickness, and
as reported by YouNG (35) is ‘‘plainly differentiated into cortical
and medullary tissues separated by a layer of procambium along
which rudimentary vascular bundles are arranged at intervals.”
There is a single, somewhat irregular layer of epidermal cells just
beneath the endosperm, and within 5 mm. of the distal end are the
two very minute, unequal cotyledons which “‘measure about 750
by 175 #” (1, 25). The cortical and medullary cells are similar
in shape and size, and are largely filled with oil and proteid bodies.
The endosperm cells, arranged with the long diameter at right
angles to a median plane, are especially rich in proteids (28). The
procambium cells with the long diameter at right angles to that of
the endosperm cells contain few or no proteid grains (fig. 1).

The outer seed coat or shell is made up of two layers; the outer
with its crinkled surface is light brown and softer in texture than
the inner layer, which is dark brown and has a glazed inner surface.
In the angles of the shell this layer seems to be of two layers which
divide, leaving spaces filled with still another tissue that is lighter
in color and softer in texture than the outer of the shell layers. In
the micropylar angles of the seed is a narrow cavity. Such cavities
are termed by BERG (1) the “‘loculi spurii in testa,” and extend the
entire length of the shell. This open channel probably serves as
the usual entrance of the parasites of the nut (fig. 1).

The tissues of the seed, taken in order, beginning with the shell

are: (1) outer seed coat in two distinct layers, with a softer tissue

filling the triangularly prismatic corners; (2) the thin inner seed
coat which may or may not adhere to the kernel; (3) the endosperm
layer, two cells thick; (4) epidermis, a single-celled layer; (5) cor-
tex, of large storage cells; (6) procambium layer, generally three
cells thick; (7) the medullary tissue, of large storage cells.

Diseases of the Brazil nut

1. BLACK CRUST

GENERAL DESCRIPTION.—Fully 5 per cent of all diseased Brazil
nuts are affected with black crust, but there is no external indica-
tion of their condition, since the shells are normal in color and the

1921] SPENCER—BRAZIL NUTS 273

weight is the same as that of sound nuts. When the shell is
removed the kernel presents a dull black appearance which, if the
whole nut is affected, reminds one of a large sclerotium. A cross-
section of the diseased kernel shows the blackened portion to consist
of a thin layer, too-250 mu in thickness, apparently having no
connection with the tissues beneath, which, aside from their light
brown color and their pronounced nut odor, appear to be normal

Fics. 1, 2.—Fig. , Diagrammatic drawings of cross and longitudinal sections
of Brazil nut: @ and _ “loctile i in testa; 0, en osperm layer; ¢, procambium layer;
d, medullary tissue; e, outer layer of outer seed coat; j, inner layer of outer seed coat;
é, = tissue filling | corners of shell; /, inner “ coat; fig. 2, pycnidium with imma-
ture spores, Pdlionidla macros pore Rh. Sp.;

(figs. 34-36). The diseased nut meats are frequently found covered
with various fungi, chiefly Penicillium or Aspergillus, with black
crust under the mold. A study of microtome sections shows that
the mycelium is in the endosperm layer, the affected cells of which
are hypertrophied (figs. 34, 35). The cortical cells of the radicle
immediately beneath are not parasitized, but their contents are
markedly changed. The proteid grains are almost or quite lacking
in the epidermal and outer layers of the normal cortex, while in
diseased nuts there is a superabundance of small proteid grains in

274 BOTANICAL GAZETTE [NOVEMBER

this region (figs. 34, 35). As it is possible to find nuts seemingly
free from any other organism, the black crust fungus is easily
isolated. Small pieces of tissue taken aseptically from immediately
below the crust on direct plating gave pure cultures.

MorpHo.tocy.—The mycelium on cornmeal agar is of two
kinds, that made up of cells which are longer than wide, and that
with cells either nearly globular or wider than they are long (figs. 18,
19). The long-celled type predominates, both in the aerial and
the submerged mycelium, except near pycnidia, where the shorter
cells are most in evidence. The long cells are 14-32 u in length
by 3.5-14 in width, the short ones measuring 10-18 yp in diameter.
Both types are thick-walled and black when mature, and both
have granular contents (figs. 19, 20). In autoclaved rice and in
the black crust of diseased nuts the hyphal cell is transformed
until the hyphae suggest chains of conidia (figs. 14, 20). These
cells are black, 1o-15X5-8y in size, and contain one or two
guttulae. They readily break away from the hyphae and function
as spores.

Pycnidia are produced sparingly, and only along the border of a
thallus where it comes in contact with another thallus, either of the
same or of some other species. No pycnidia were found on dis-
eased nuts or on any of the cultures except those on cornmeal agar
plates. They are black, smooth, globose-conical, beaked, and
150-350indiameter. The beak is 100-250 yp in length (figs. 2, 21).

The spores are borne at the base of the pycnidial cavity on
short, hyaline, often septate conidiophores which are interspersed
with narrow strap-shaped, hyaline, continuous paraphyses that
are from one to six times as long as the conidiophores, the conidio-
phores being 5-14 4 in length by 3-5 uw in width (fig. 13). The
spores are at first hyaline, unicellular, 26-36 X 14-20 u in size and
irregular in shape, but with maturity they become sooty black,

striated, uniseptate, regular in shape and uniform in size, being
28 X14 p (fig. 15).

CULTURE CHARACTERS.—On cornmeal agar plates the fungus
grows at the rate of o.5-o.7 mm. per day at room temperature.
The thallus is at first milk white, and the margin of it remains
uncolored so long as it is increasing in size. After five or six days

1921] SPENCER—BRAZIL NUTS 275

the central portion becomes green, and a few days later turns sooty
black. The thallus then is made up of three concentric rings, the
outer white, the next green, and the innermost black (fig. 11).
As the thallus ages it shows marked zonation, and becomes entirely
black when growth ceases. Aerial mycelium is produced on all
parts of the thallus, but is most luxuriant in the central area. On
Brazil nut agar the growth is very much slower than on cornmeal
agar, usually 0.3 mm. per day at room temperature, and the en-
tire thallus remains hyaline. On nut plugs the growth was very
weak, but a crust similar to that of naturally diseased nuts was
formed after three months. On autoclaved rice the growth was
vigorous, and several characteristic color reactions were noted
(fig. 8). Eight days after inoculation: aerial mycelium snow white
with line of Antique Green’ below; rice grains in contact with
glass, white bordered with Cerulian Blue; all interstices with
greenish tints. After fifteen days: aerial mycelium white with
lower border line Prussian Blue, almost black; contacts of grains
with glass white bordered with Prussian Blue; interstices purple
tinged.

The hyaline immature spores as well as the black mature ones
germinated readily. The immature spores occasionally germinated
in ten minutes after planting, while more than an hour is required
for the germination of the mature spores, but the germ tubes of the
mature ones soon outstrip those of the immature (figs. 16, 17).
There is no change in either spore, except a slight swelling in
germination, the immature spore remaining unicellular. This phe-
nomenon of the germination of immature as well as mature spores
has been pictured by Hicerns (11) for a related species.

TAaxoNnomy.—The morphological characters of the fungus are
those of Pellioniella Sacc., but according to SACCARDO (25) there
is but one species in the genus, P. deformans Penz. and Sacc.,
whose spore measurements are a little more than half those of the
Brazil nut parasite. The fungus, therefore, is given the name
Pellioniella macros pora.

* The nomenclature used in describing colors throughout these investigations is
that given in Ropert Rmwceway’s Color standards and color nomenclature, pub-
lished by the author, Washington, D.C. ror2.

276 BOTANICAL GAZETTE [NOVEMBER

Pellioniella macrospora, n. sp.—Pycnidia sparse, smooth,
carbonaceous, globose-conical, beaked, 150-350 in diameter,
beak 1oo-250 uw in length. Conidiophores at base of pycnidial
cavity, hyaline, often septate, 5-15 3-5 uw. Paraphyses hyaline,
strap-shaped, continuous, 5-5ou. Immature conidia hyaline,
unicellular, irregular, 26-36 14-20 wu; mature conidia sooty black,
striated, uniseptate, regular, 28 X14 wu.

Hasitat.—Parasitic on endosperm of seed of Bertholletia
nobilis Miers and B. excelsa Humb. and Bonpl.

2. WHITE MOLD

GENERAL DESCRIPTION.—White mold is not so common as
black crust, and is probably responsible for less than 1 per cent of
the Brazil nut decay, but it is a real factor in this loss. The
diseased nut is normal in external appearance, but is below normal
in weight. When cracked, the white, fluffy mycelium is seen to
cover the entire kernel, but soon after exposure the hyphae collapse
and the yellowed endosperm becomes visible through the mycelial
mass. A pronounced musty odor arises from the newly shelled
nut, but the taste of the diseased meat has nothing to distinguish
it. A cross-section of the nut kernel shows three typical features
of the disease: (1) the white moldy covering; (2) the endosperm
layer, sulphur-yellow in color and more than twice as thick as in
the normal nut; and (3) irregular cracks and cavities in the
radicle, all filled with white mycelium and spores. The mycelium
penetrates to the center of the radicle. The hyphae in the tissue
are very tenuous, less than 2 y in diameter, and are usually so
closely associated with the cell walls of the host tissue as to make a
study of them in situ very difficult, but the cell walls of the diseased
nut are penetrated by them. The fungus was isolated as described,
but spore dilutions made by touching a sterile loop to the mycelial
mass in the internal check of the kernel gave pure cultures also.

MorPxHoLocy.—Mycelium taken from the nut, from nut plugs,
and from other media was uniform in character. The following
description is of mycelium taken from cornmeal agar plates. The
cells measure 20-70 X3.5-10.5 uw, and are hyaline with granular
contents and guttulae. Anastomosis of cells is of frequent occur-

1921] SPENCER—BRAZIL NUTS 277

rence, especially in the submerged hyphae, while in the aerial
mycelium simple loops and coils are common (fig. 24). The hyphae
are unconstricted at the septa, and unbranched cells are of quite
uniform size throughout their length. Cells bearing branches
are swollen at the points from which the branches arise.

10:05 AM

17:00 AM. 12-95. EP,
G. 3.—Development of spore mass of sidiceaeges eh bertholletianum n. sp.; .
a line shows size of water drop surrounding mass; 100

The conidiophores, 50-90 » in length, are in most instances
simple branches from either a principal filament or from its branches.
They are spindle-like, with rounded tips from which the spores
are cut off (fig. 3). The single-celled, oblong-elliptical, hyaline
conidia are 8-12%3.5-54 4 in size, and contain two guttulae
(fig. 23). They collect, as they are produced, in a spherical mass
at the end of the conidiophore. A drop of water surrounds the
spore mass after the third spore arrives (fig. 3).

278 BOTANICAL GAZETTE [NOVEMBER

CULTURE CHARACTERS.—On cornmeal agar the fungus grows
rather rapidly, o.5-1.0 cm. daily at room temperature. The thal-
lus is: very regular and is distinctly zonated after reaching a
diameter of 4 or 5cm. There is a dense growth of white aerial
mycelium on the older portions of the thallus. On Brazil nut
agar the characters are as previously stated, except that the
growth is a little more rapid, and a halo 3 mm. wide, due to the
digestion of the solid proteids, surrounds the thallus. On nut
plugs the fungus grows luxuriantly and destroys the nut meat
without giving off any appreciable odor. A large amount of fluffy
mycelium is the characteristic feature of its growth on nut plugs
as it is on the nut in the shell. On autoclaved rice the growth is
vigorous and a pink tinge appears in the medium after two days.
After ten days four colors are distinguished; where the rice is in
contact with the glass in the older portions, Ochraceous Buff, in the
younger, Venetian Pink; interstices between the grains are filled
with mycelium through which a Jasper Pink color shows, in the
older portions; in the younger portions it is Light Hortense Violet.

The nut strip above the water is soon covered with the dense
mycelium, and is appreciably shrunken within five days. The
strip in the water remains intact, but the water is soon filled with
the mycelium which makes its way upward from the strip at the
bottom. In hanging drop the spores germinate with a single
germ tube, which in the most vigorous, at room temperature, may
attain the length of the spore in two hours after planting. Spore
production in hanging drop at room temperature proceeds at the
rate of about one spore per hour per conidiophore. The conidio-
phore lengthens and increases in diameter as the conidia are cut
off at the end. The process is very like spore production of Tricho-
thecium as described by Linpav (14).

TaxonoMy.—The fungus evidently belongs to Cephalosporium,
but none of the species of this genus as reported by SACCARDO
(25) has characters sufficiently like the Brazil nut parasite to permit
it to be classified as one of them. C. fructigenum McAlp. (15) has
spores of almost identical shape, size, and appearance, but it has
knobbed conidiophores and oblong spore masses which are not pres-
ent in this species, which therefore is described as new.

1921] SPENCER—BRAZIL NUTS 279

Cephalosporium bertholletianum, n. sp.—Conidiophores hya-
line, simple or dichotomously branched, 50-90 p long, 2- to 4-septate;
spore mass globular; conidia hyaline, unicellular, oblong-elliptical,
guttulate, 6-12 X3.5—5 wu, ends obtuse.

Hasitat.—On radicle of seed of Bertholletia nobilis Miers and
B. excelsa Humb. and Bonpl., causing decay.

3. DRY ROT

GENERAL DESCRIPTION.—The shell of the nut affected by dry
rot is mottled, but of somewhat lighter shade in its darkest areas
than the shells of normal nuts, and the weight is much below normal.
The cracked shell appears to be filled with a kernel which adheres
more closely to the shell than is usual, but which is so similar in
color and general appearance to that of sound nut kernels that it
might easily pass casual observation as such, although in reality
it is merely a mass of mycelium. Small pieces of mycelium taken
from this mass swell to approximately twice their size when placed
in water. Under the microscope the hyphae were seen to be
irregularly branched and septate. No conidiophores were seen,
but what appeared to be unicellular elongated conidia of greatly
varying length were occasionally found.

MorpHoLocy.—The hyphae which make up both the aerial
and the submerged mycelium are irregularly branched, and more
or less constricted at the septa. The cells are 14-90 u long by
3-5-11 pw wide, hyaline with granular contents and guttulae (fig. 44).
Anastomosis frequently occurs, especially in older thalli, when
spores falling on the medium germinate, producing a tube which
unites with the cell of an older hypha, another germ tube, or an-
other spore (figs. 29, 48).

The simple conidiophores are borne at any place along the
hyphal strand, seldom more than two being produced by a single
cell. Branched conidiophores are rare. Thalli resulting from
direct planting of mycelium taken from the diseased nut produce
but few conidiophores, and rarely more than single-celled conidia.
Conidia from transferred cultures are from 1- to 8-celled, sub-
cylindrical, slightly sickle-shaped, without pedicel, and conical
at base (fig. 42).

280 BOTANICAL GAZETTE [NOVEMBER

No perithecia were found, but sclerotia were formed on auto-
claved rice. These are dark gray and 500-1000 uw in diameter.
Terminal chlamydospores are produced on 60-day old cultures.
They are globular or oblong, with an average mean diameter of 14 p,
and with a scarcely perceptible yellow tinge (fig. 45)

CULTURE CHARACTERS.—Pure cultures are easily obtained by
directly planting pieces of mycelium taken from the innermost
portion of the mycelial mass. On cornmeal agar the rate of
growth averages o.5 cm. daily at room temperature. The thallus
is arachnoid and regularly zonated, the zones averaging 0.5 cm.
in width. Aerial mycelium covers the entire thallus but is most
luxuriant in the central area, and there it is tufted. On Brazil nut
agar the growth is more dense and a little more rapid than on corn-
meal agar, its rate being from o.7 to 1.0 u at room temperature.
An extra-cellular, proteolytic enzyme is secreted, causing a halo
of 3-5 mm. in width in the medium surrounding the thallus. The
aerial mycelium is more luxuriant on this agar than on the other.

The fungus grows vigorously on nut plugs, so that in a few days
the plugs are enveloped with the snow-white mycelium, while a
putrid odor is exhaled. After two or three months the plugs are
completely reduced and only a mycelial mass remains. There is
no color change on autoclaved rice until it shrinks away from the
tube, when it is Maize Yellow. The fluffy, white, aerial mycelium
surmounts the rice column and covers its sides as the growth
proceeds downward. Apparently complete destruction of the
rice is accomplished within two months. On carrot plugs the
growth is not so rapid as on other media, but is marked by an
abundance of white aerial mycelium. It is without color change.
On the strip of nut meat above the water the growth is vigorous,
and if the water surface remains near enough to the strip it is
destroyed within eight or ten days. The strip in the water often
appeared to be intact when it was not, the mycelium retaining the
outline. It was probably destroyed as soon as the strip above.

In hanging drop the conidia begin germinating after three or-
four hours at room temperature, but many of them require twenty-
four hours or more. Seldom more than two cells of a spore germi-
nate, but frequently one cell produces two germ tubes (fig. 46). It
often happens that spores are united by a short germ tube. Occa-

1921] SPENCER—BRAZIL NUTS 281

sionally four or five conidia are connected in this way (fig. 47),
resulting, as.is clearly shown by drop cultures, from germination
succeeded by anastomosis (fig. 48). In all cultures the dense
mycelium collects and retains water enough to germinate the 1- and
2-celled spores, and their germ tubes anastomose readily with the
first cells, conidial or hyphal, with which they come in contact.
It is often difficult to distinguish between conidiophores bearing
conidia and conidia anastomosed to hyphal cells with a short germ
tube (fig. 44).

Taxonomy.—The fungus is a species of Fusarium which,
according to WOLLENWEBER’S (34) scheme of classification, belongs
to the section Eupionnotes: chlamydospores present; perithecia
unknown; conidia subcylindrical, sickle-shaped; base without
pedicel, conical; terminal chlamydospores.

4. ASPERGILLUS DECAY

GENERAL DESCRIPTION.—Brazil nuts attacked by Aspergillus
may give no external indication of their internal condition except
in the most advanced stages of the disease, when the weight of the
nut is appreciably lowered. The kernel shrinks, often cracks
open, and is always covered with a mass of dark brown spores.
The odor of the diseased nut is strongly rancid with a putrid taint;
the taste is at first sour, later very bitter. Occasionally nuts that
are merely discolored have this same taste. Kuunt (13) states that
Brazil nuts affected with Aspergillus flavus Mont. are poisonous,
and that the discoloration caused by this fungus is so slight that it
does not prevent their being eaten. Both his observations and my
own indicate that the disease, although present, may often escape
notice, and that it is really far more prevalent than it appears to
be under superficial examination. Nuts in advanced stages of the
disease, however, occur less frequently than black crust. The
mycelium of the fungus penetrates the tissues to the center of the
nut, and when there is a central locule, appears as a white mold on
the walls of the locule. When the diseased kernels crack open, a
mass of spores fills the locular space.

Morpuotocy.—The mycelium consists of irregularly branched
hyphae which are slightly constricted at the septa (fig. 31). The
cells are 20-65 X 3.5-11 m, with granular contents of a faint greenish

282 BOTANICAL GAZETTE [NOVEMBER

tint. Conidiophores varying from ten to several hundred microns
in length arise at irregular intervals from the hyphae. The shortest
of these have little or no filamentous part, but consist merely of
the head and sterigmata (fig. 28). Sterigmata are also borne singly
and in groups of from two to four on the hyphal cells (fig. 27).
The heads of the conidiophores measure 10-20 uw in diameter, and
the sterigmata, from two to many per head, are 10-12 5-7 up.
The globular, echinulated conidia are of different shades of
yellow, and 5-10 uw in diameter, but the predominant size is 7 u
(fig. 29). |

CULTURE CHARACTERS.—On cornmeal agar the rate of growth
varies from 0.3 to 1.0mm. daily at room temperature, and after
forty-eight hours the central portion of the thallus shows the
forming spore clusters in Light-Buff. The spore masses become
darker with age until Lemon-Chrome is finally reached. On Brazil
nut agar the growth is very similar to that on cornmeal agar, but
with a halo 1 to 2 mm. in width, showing the presence of an extra-
cellular, proteolytic enzyme surrounding the thallus. The color
of the spore mass at maturity is from Orange-Cinnamon to Mikado-
Brown. On nut plugs the growth is rapid, and a gas with the
odor of carbon bisulphide is evident. The color of the spore mass
is Primrose-Yellow at first, Honey-Yellow to Tawny-Olive at
maturity. At the end of two or three months all that remains of
the nut plug is a mass of partially disintegrated cell walls in a mass
of mycelium.

The growth on autoclaved rice is vigorous, with spore masses
forming within forty-eight hours. There is little change in the
color of the medium except for the development of a slight greenish-
yellow tint below the spore mass. The color of the spore mass
changes from Oil-Yellow to Orange-Cetrine. The odor of a 30-day
old culture is very like that of cider vinegar. The nut strip above
the water is entirely covered with spore masses within three days,
but only about one-fourth of it is destroyed before it becomes too
dry to support the fungus. A luxuriant growth of mycelium arises
from the strip in the water, and usually the strip is destroyed before
fifteen days.

1921] SPENCER—BRAZIL NUTS 283

Taxonomy.—A culture of this species was sent to CHARLES
THom, and the following excerpt is taken from his reply dated
January 29, 1920:

The organism belongs to the general group in which we are trying to
separate three lines, the Aspergillus oryzae-flavus line, the Aspergillus wentii
section, and the one which has been designated by Kira as Aspergillus tamari.
This one, from the examination today, would appear to belong to the section
containing A. famari. Whether it is safe to identify it under an existing
name or not would be doubtful.

5. BACTERIAL DECAY

GENERAL DESCRIPTION AND MORPHOLOGICAL CHARACTERS.—
When Brazil nuts are affected by. this bacterial decay, the shell
is black and greasy, and usually exhales a rancid odor. When the
shell is cracked open the remains of the kernel are found as a
white mass which ordinarily fills only a small portion of the shell
cavity. Microscopic examination of fragments of the refuse shows
numerous bacterial spores, but usually no vegetative forms and no
fungi. When dilution plates were made from the decayed residue,
one spore-bearing organism largely predominated.

The vegetative cells of the organisms in cornmeal broth are
rod-shaped, rounded at the ends, vigorously motile, and usually
single but often in chains of from two to six individuals. The rods
measure 2.5-5.0 uXo.8-1.2 uw. Spores are formed within forty-
eight hours in one end of the vegetative cells. When the cells are
stained by LorFFieR’s method, the organism is found to have
humerous long, peritrichiate flagella; stained with LOEFFLER’s
methylene blue the protoplasm is seen to be granular with from two
to four darkened patches which are unevenly distributed, usually _
giving a banded effect, although often the bands are oblique as well
as horizontal (fig. 38). The organism stains readily with methylene
blue, Gentian violet, and carbol-fuchsin, but it is Gram negative.

When sterile nut plugs were inoculated with the bacillus from
pure culture, they were reduced in about fifteen days to an oily
mass which, in all essential characters, was like the remains of the
nut kernels in the natural cases of nut decay. Dilution plates
made from nut meats that had decayed, following pure culture

284 BOTANICAL GAZETTE [NOVEMBER

inoculation, showed only one type of colony, and this proved to
consist of the organism with which the plugs had been inoculated.
The organism had no appreciable effect on the nut strip above the
water, and the strip in the water was only very slowly decomposed,
but strips in cornmeal bouillon were completely destroyed within
ten to fifteen days. The organism grows best in the presence of
air, as the colonies on all plated media and stab culture show, but
deep lenticular colonies (fig. 40), and colonies next to the glass
(fig. 39) in agar plates, as well as the faint line of growth along
the stab, indicate that it is a facultative anaerobe.

While none of the usual tests for particular enzymes was
made, the reactions in different culture media indicate the produc-
tion of diastase, invertase, rennet, and pepsin. In Brazil nut agar
plates there is formed a transparent halo about the colony, and as
the opacity of the agar is due to the presence of solid proteid matter
(20), the halo results from the digesting of these proteids. There
is an abundant secretion of the protease which makes the halo,
as the diameter of the transparent area is from two to three times
that of the colony itself. This enzyme was precipitated as already
described, and drops of a water solution of the dried precipitate
placed on Brazil nut agar plates. A transparent area as large as
the drop of solution was formed in a plate 2 mm. thick in from two
to three hours.

The organism seems to be an undescribed one, and a complete
description of it will be given in a separate paper.

6. ACTINOMYCES DECAY

GENERAL DESCRIPTION AND MORPHOLOGY.—Empty shells that

are intact and still retain their normal color are occasionally found
among Brazil nuts. When these shells are cracked open a char-
acteristic musty odor is evident, and the inner shell wall is seen
to be covered with pinkish velvety pustules that are from one to
several millimeters in diameter. Water mounts of pieces of a
pustule show tenuous, mycelial-like strands, or chains of spores
which readily stain with carbol-fuchsin. The filaments are not
long but branch, and the mass is so bound together by the branches
that it is quite impossible to separate entire filaments from the mass.

e°
1921] SPENCER—BRAZIL NUTS 285

The filaments are never entirely straight nor yet very crooked, and
chains of spores are usually contained in the free ends (fig. 37).
No spirals were found on any of the media. The diameter of the
filaments varies from 1.0 to 1.3 uw, and the oblong spores measure
1.6 Xo.8 uy.

The germination of spores was studied with an oil immersion
lens, in a hanging drop prepared as follows. A thin film of synthetic
agar was spread on a thin cover-glass, and a loop full of a dilute
spore suspension placed on the agar film. This was inverted over
a dry Van Tieghem cell. The water soon evaporated, leaving the
spores in contact with the agar, where their germination was
easily studied and camera lucida drawings made. According to
DRECHSLER (9), Actinomyces spores produce from one to four
germ tubes, ‘‘the approximate number being more or less char-
acteristic of the species.’ This species produces one and two
germ tubes which often branch directly on leaving the conidium
(fig. 36).

The organism was studied in the manner suggested by CoNN
(3) and Waxksman (33), and the media were made in accordance
with directions given by WAKSMAN (33). The following culture
characters were noted:

CULTURAL CHARACTERS.—1. Synthetic agar: room tempera-
ture, after ten days: growth densely compact but thalli small, at
first white, but after ten days Pale Pinkish Buff; aerial mycelium
white and dense; soluble pigment none.

2. Calcium malate-glycerin agar: growth spreading and not
zonated, bordered by submerged mycelial bands of varying width,
pearl white; aerial mycelium short, loose, and pearl white; soluble
pigment.

3. Glucose agar: growth luxuriant, color same as in synthetic
agar, thallus conspicuously zonated; aerial mycelium white to
Pale Pinkish Buff, powdery; soluble pigment none.

4. Glycerin agar: growth densely compact, not zonated, Pale
Pinkish Buff; aerial mycelium powdery, white; soluble pigment
none.

5. Brazil nut agar: growth rapid, densely compact with wide
margin of submerged mycelium, white to Pale Pinkish Buff;

286 BOTANICAL GAZETTE NOVEMBER

aerial mycelium dense, white; soluble pigment none; enzymatic
zone three to four times the diameter of thallus.

6. Cornmeal agar: growth dense but zonated, Pale Pinkish
Buff; aerial mycelium powdery; soluble pigment none.

7. Egg albumin agar: growth thin, conspicuously zonated,
Pale Pinkish Buff; aerial mycelium powdery, Pale Pinkish Buff;
soluble pigment none.

8. Nut plugs: growth vigorous, Pale Pinkish Buff; aerial
mycelium powdery, white; medium not completely destroyed,
but much shrunken and blackened.

9. Autoclaved rice: growth vigorous, Pale Pinkish Buff; aerial
mycelium 2cm.; almost completely destroyed in sixty days.

1o. Potato plugs: growth vigorous, crumpled, Pale Pinkish
Buff; aerial mycelium abundant, at first white, later Pale Pinkish
Buff; medium with no change in seis much reduced in size in
two months.

11. Carrot plugs: growth at first slow, appearing after five
days, crumpled and dense, Pale Pinkish Buff; aerial mycelium
powdery, at first white, later Pale Pinkish Buff; medium darkened
near the growth, no change in color in other regions, much shrunken.

12. Brazil nut bouillon: growth surface pellicle, snow-white;
aerial mycelium white, powdery; medium somewhat clarified.

13. Nut strips: growth slight on strip above water, and none on
strip in water; no growth on surface of water. :

BIOCHEMICAL FEATURES.—The proteolytic enzyme which makes
the halo in Brazil nut agar plates was the only one studied, but the
growth reactions in different media were taken to indicate the
probable production of several other enzymes, diastase and inver-
tase especially. The proteolytic enzyme was isolated by precipita-
tion, as previously described, and its proteolytic power tested by
placing drops of a water solution of the dried precipitate on Brazil
nut agar plates. Transparent areas the size of the drops developed
in from two to three hours, depending upon the thickness of the
agar plates.

Taxonomy.—The organism is an Actinomyces which, according
to WAKSMAN’S key, belongs in division B, ‘‘no soluble pigment
produced on gelatin or other protein media,” and in section J,

1921] _ SPENCER—BRAZIL NUTS 287

“species strongly proteolytic; gelatin liquefied rapidly, milk
clotted and peptonized rapidly.” No species given in this division
and section, however, has the characteristics of the one found in
Brazil nut shells. It is therefore given the name of Actinomyces
brasiliensis.

Actinomyces brasiliensis, n. sp.—Straight, branched hyphae
1.0-1.3 win diameter; spores borne in chains in free ends of hyphae,
oblong, 1.6 X0.8 w; growth Pale Pinkish Buff on all agars except
calcium malate-glycerin, on which it is white; zonated on glucose,
cornmeal, and egg albumin agars; aerial mycelium on al! media,
white to Pale Pinkish Buff; no soluble pigment formed.

Hapirat.—Parasitic on kernels of Brazil nuts.

7. PHOMOPSIS DECAY

GENERAL DESCRIPTION.—Only one nut was found affected
with Phomopsis decay, but because of its striking diagnostic
features the fungus was isolated and studied. There was no
external indication of the diseased condition, but the kernel of the
nut was rich brown, with a few black specks near one end. The
odor of the nut was pleasant and the taste agreeable. Stained
hand sections showed that the mycelium of the fungus had pene-
trated into the radicle to considerable depth.

MorpPHotocy.—The mycelium was tenuous, septate, and at
first hyaline, but soon became brown or smoke colored. According
to DiEpDIcKE (8), the form of the pycnidia is greatly varied. In the
Brazil nut species several of the forms pictured by DrepIcKE were
observed, but the one most commonly met with was mammiform,
with a wartlike protuberance. The irregular pycnidial cavity so
common to the genus was frequently observed, but a regular
Cavity was the rule. Two forms of spores were present in all
pycnidia examined (fig. 50), and as is customary, the Phoma type
will be designated as A, the filamentous as B spores. The B
form did not germinate in hanging drop, a fact supporting the
Statement made by Grove (10) that these may or may not be
spores. When they fail to germinate they are probably what
SACCARDO (25) took them to be, conidiophores, which according
to Grove ‘‘become more curved than when in situ.” The A

288 BOTANICAL GAZETTE [NOVEMBER

spores are oblong-elliptical, hyaline, guttulate, and measure
5-7 X1.7-3.5 uw. The B spores are filiform, usually hook-shaped,
hyaline, continuous, and measure from 17—24.5 X2-3.5 yp.

CULTURE CHARACTERS.—The fungus grew well on all media
used. On cornmeal agar the thallus was circular and without »
zonations. A loose aerial mycelium covered the entire thallus,
and numerous pycnidia varying in size were scattered over the
surface of the plate. The pycnidia appeared simultaneously with
the brown color, which was usually noticed after five or six days.
On Brazil nut agar the growth was similar to that on cornmeal
agar. The clear halo formed in the agar plate barely exceeded
the size of the thallus. On autoclaved rice a brown or smoky color,
due to the mycelial growth, was noticeable, but no color change
occurred in the medium. Nut plugs were soon covered with a
brown mycelium which later became almost black. The surface
was soon covered with black, wartlike pycnidia, and the entire
_ mass when cut through suggested a dried sponge. The odor was
similar to that of very rancid nuts. The fungus made no growth
on nut strips above the water, but a dense mass of mycelium, filled
with black strands, developed on the strips in the water. These
strips retained their form, but the cessation of mycelial growth,
which occurred between ten and fifteen days after inoculation,
. marked the time of nutrient exhaustion.

Taxonomy.—The fungus is a typical Phomopsis which
approaches P. aucubicola Grove more nearly than any other
described species. A spores are shorter, and this, coupled with the
fact that it occurs on an unrelated host, necessitates describing it
as new.

Phomopsis bertholletianum, n. sp.—Pycnidium dark brown,
mammiform, with wartlike protuberance, irregular in shape and
size, varying from o.1 to 1.0; conidiophores filiform, hyaline,
continuous, 15-20 yw long, often indistinguishable from B spores.
A and B spores present, A spores oblong-elliptical, hyaline, guttu-
late, 5-7X1.7-3-5@; B spores filiform, usually hook-shaped,
hyaline, continuous, 17-24.5 X 2-3.5 um.

Hasitat.—Parasitic on kernels of Brazil nuts.

1921] ' SPENCER—BRAZIL NUTS 289

8. BITTER ROT

Figure 4 shows a part of a Brazil nut affected with bitter rot, and
fig. 49 shows spores of the fungus, two of which have conidiophores
attached. Neither the spores nor the mycelium was viable, and
time prevented more than a superficial examination being made.
The fungus is apparently a Myxosporium.

— TEACHERS COLLEGE
PE GIRARDEAU, Mo.

LITERATURE CITED
- BERG, Orro, Bertholletia excelsa Hb. et Bpl., Martii Flora Braziliensis.
14:478. 1859.
2. CHAMBERLAIN, C. J., Methods in plant histology. University of Chicago
Press. Chicago. 1915.

Leal

3. Conn, H. J., The possible function of Actinomyces in soil. Jour. Bact.
1107: To16,
4. , Soil flora studies, V. Actinomyces in soil. N.Y. Agric. Expt.

Sta. Tech. Bull. 60. 1917.

5. CHESTER, F. D., A manual of determinative bacteriology. Macmillan |

Co. New York. ro14.

- Corset, L. C., Cold storage. W.Va. Agric. Expt. Sta. Bull. 75. rgor.

. Department of Commerce. Brazil and Cream nuts. Mont y Rue
of Foreign Commerce of the United States. December, roro.

8. Diepicke, H., Die Gattung Phomopsis. Ann. Myc. 9:8. ro1t.

9. DRECHSLER, C. , Morphology of the genus Actinomyces. Bor. Gaz. 67:65-

83; 147-168. 1910.

10. GROVE, W. B., The British species of Phomopsis. Roy. Bot. Gard., Kew
Bull. Misc. Tnfora, no. 2. 1917 (p. 49).

- Hicerys, B. B., Plum wilt, its nature and cause. Ga. Agric. Expt. Sta.
Bull. 118. seed

12. Jones, L. R., Pectinase the cytolytic enzyme produced by Bacillus caro-
tovorus and certs other soft-rot organisms. N.Y. Agric. Expt. Sta.
Tech. Bull. 11. 1909.

- Kunz, Huco, Uber eine eigenartige Veranderung der Paranuss. Pharm.
Zentralh. 51:106. 1910

- Linpau, G., Trickaucion roseum. Rabenhorst’s Kryptogamen-Flora.
8:366. 1

. McAreieg. D., Fungus diseases of stone-fruit trees in Australia. Dept.
Agric., Melbourne, Victoria. 1902.

16. McMurran, S. M., Diseases of trees. Amer. Nut Jour. 4:81. 1916.

“uO

al
Leal

Lal
w

-
a

Cl
on

i)
wn

BOTANICAL GAZETTE {NOVEMBER

. Mancin, M. L., La Pourriture des Chataignes. L’Aced. D’Agr. France.
4:885. 1918.
. MARTz, Diseases and insect pests of the pecan. Fla. Agric. Expt. Sta.
Bull. 14 Be
IGU W., em der Bacterien. Handbuch der Morphologie Ent-
ei ae ae und Systematik der Bacterien. Verlag von Gustav

ischer, Jena. 1900.
. OsBorne, T. B., os Crapp, S. H., Hydrolysis of excelsin. Amer. Jour.
Phys. 19:53.
RCE, N. B. Wein bacteriosis. Bor. GAz. 31:272. I

. PEARSON, C. H., Uses of the Brazil nut tree. Amer. "ie 23:782.

1910.
. Ranp, F. V., Some diseases of pecans. Jour. Agric. Res. 1:303.
. RuMBOLD, CAROLINE, Notes on chestnut fruits infected with the ao
blight fungus. Phytopath. 5:64. 1915.
. SaccaRDO, P. A., Sylloge Fungorum. Vol. XVIII.
HEAR, C. L., and StEvENsS, NEtr E., Cultural ae aie of the chestnut
blight fungus. U.S. Dept. Agric. B. PL. Cr. 321:
. SmMitH, R. E., Walnut culture in California, atid blight. Cal. Agric.
Expt. Sta. Bull. 24%. 1077.
. STRASBURGER, E., Textbook of botany, 4th Eng. ed. Macmillan Co.
London. 1912.
. Stuckey, R. P., Pecans, varieties, influence of climate, soil, stock on scion.
Ga. Agric. Expt. Sta. Bull. 116. rors.
. TURNER, WiLL1AM F., Nezara viridula and kernel spot of pecan. Science
47: 490. 1918.
. Von Ivanorr, K. S., Uber Trichothecium roseum Link als Ursache der
Bitterfaule von Frvcten. Zeitsch. Pfl’kheit 14:36. 1904
. VAUGHAN, R. E., A method for the differential staining of fungus and host
cells. Ann. Mo. Bot. Gard. 1:241. 1914.
WaksmaN, S. A., Cultural studies of species of Actinomyces. Soil Sci.
8:71. 1918.
. WOLLENWEBER, E. W-, sone a geosphacrelie, Nectria, Calonectria.
Eine Morpl zur Abgrenzung von a
mit cylindrischen und aio ead ana EB Phytopath. 3:
197- 1913
. Young, W. J., A study of nuts with special reference to microscopic identi-
fication. U.S. Dept. Agric. Bur. Chem. Bull. 160.

EXPLANATION OF PLATES VIII-XII
All drawings were made with camera lucida.
PLATE VIII
Fic. 4.—Part of Brazil nut kernel affected by bitter rot; Xr.
Fic. 5.—Thalli of Actinomyces brasiliensis n. sp. on cornmeal agar; X#-

1921] - SPENCER—BRAZIL NUTS 201

Fic. 6.—Thallus of Actinomyces brasiliensis n. sp. on cornmeal agar; X 2}.

Fic. 7.—Colony of Bacillus from Brazil nut on cornmeal agar; X2.

Fic. 8.—Pellioniella macrospora n. sp. in autoclaved rice; tube on right
20 days old; tube on left 10 days old; Xx.

Fic. 9.—Brazil nut 30 days after inoculation with Pellioniella macrospora
n. sp.; nut plug at top marks place of inoculation, and along two edges inner
seed coat removed to expose blackened endosperm; Xr.

Fic. 10.—Thallus of Actinomyces brasiliensis n. sp. on Brazil nut agar, sur-
rounded by transparent area in which proteids have been digested owing to
secretion of proteolytic enzyme; X13.

1G. 11.—Thallus of Pellioniella macrospora n. sp. on cornmeal agar:
three zones: (1) scarcely visible outer zone of white; (2) zone of nearly same
width that is green in growing thallus; (3) inner black circle; X#.

1G. 12.—Actinomyces brasiliensis n. sp. on potato plug after 10 days; X1.

PLATE IX

Fic. 13.—Paraphyses, immature conidia, and conidiophores of Pellioniella
macrospora n. Sp.; X500

Fic. 14. Conidin like cells of hyphae of P. macrospora n. sp. from dis-
eased tissue of Brazil nut; 500.

Fic. 15.—Mature, immature, and transitional stages in development of
conidia of P. macrespore n. SP-j ree 502.

Fic. 16. idia of P. macrospora n. sp., planted
in same hanging drop with mature conidia shown in figure 18; X 500.

1G. 17.—Germination of mature conidia of P. macrospora n. sp.; germ

tubes from one to two hours longer in emerging than those of immature conidia
shown in figure 17; 500

Fic. 18.—Hypha of P. macrospora n. sp., showing most common type of
cell; 500.

Fic. 19.—Hypha of P. macrospora n. sp. from near pycnidium; X 500.

Fic. 20.—Conidia-like cells of hyphae of P. macrospora n. sp., taken from
culture in autoclaved rice; 500

1G. 21.—Section of pycnidium of P. macrospora n. sp., enlarged about

450 diameters.

Fic. 22.—Hyphae of P. macrospora n. sp., showing two types of cells;

PLATE X

Fic. 23.—Conidia of Cephalosporium bertholletianum n. sp.;

Fic. 24.—Hyphae, conleinece and spore masses ae re water
drops, C. bertholletianum n. sp.; X 500.

Fic. 25.—Germinating osnidta of C. bertholletianum n. sp., two hours after
planting; X 500.

Fic. 26.—Germinating conidia of C. bertholletianum n. sp., twenty hours
after planting; X 500.

292 ; BOTANICAL GAZETTE [NOVEMBER

Fic. 27.—Hyphae of Brazil nut Aspergillus bearing sterigmata; X 500.

Fic. 28.—Hypha of Brazil nut Aspergillus bearing short stalked conidio-
phores; X 500. 7

Fic. 29.—Conidia of Brazil nut Aspergillus; 500.

Fic. 30.—Mature conidiophores of Brazil nut Aspergillus; X 500.

Fic. 31.—Hyphae showing branching habit and anastomosis, Brazil nut
Aspersillas X 500

32. Baty stages of conidiophores of Brazil nut Aspergillus; X 500.
PLATE XI

Fic. 33-—Microtome section of normal nut kernel showing tissues named
in order, beginning at top: endosperm, epidermis, cortex, procambium, and
medulla; x5

FIG. 34 _-Microtdyss section of Brazil nut affected by Pellioniella macro-
spora n. sp., showing dense mycelial growth in endosperm region; X 1000.

Fic. 35.—Microtome section of Brazil nut affected by P. macrospora n. sp.,
hovide relation of fungus to host tissues; 500

Fic. 36.—Germinating conidia of ‘Litheuncas brasiliensis n. sp.; 1000.

Fic. 37.—Hyphae and conidia, Aciinomyces brasiliensis n. sp.; > 1000.

Fic. 38.—Vegetative cells of Brazil nut bacillus; 1000.

Fic. 39.—Colony of Brazil nut bacillus growing near glass in cornmeal

agar plate; >50.
1G. 40.—Deep colony of Brazil nut bacillus n. sp.; X 50.
Fic. 41.—Surface colony of Brazil nut bacillus n. sp.; X50.

"PLATE XI
Fics. 42-49, and 51 are of a Fusarium which causes dry rot of Brazil nuts.

Fic. 42.—Conidial variation and anastomosis; 500
Fic. 43.—Typical hyphae showing difference in size asd branching habit;

Fic. 44.—Hyphae bearing single conidiophores and conidia anastomosed
to hyphal cells by germ tube; X 500

Fic. 45.—Terminal SE REES X 500

Fic. 46.—Germinating conidia in hanging dca culture; 500

Fic. 47.-—Anastomosing conidia and hyphae from culture site: X 500.

Fic. 48.—Anastomosis of germinating conidia in hanging drop; 500.

Fic. 49.—Conidia ‘ie bcupiaaree of bitter rot fungus, taken from
pustules on diseased k ‘00.

FIG. 50. Pelee se two having germ tubes attached; X 500.

Fic. 51.—Hyphae of Fusarium from washed agar plates; X 500.

BOTANICAL GAZETTE, LXXII PLATE VIII

SPENCER on BRAZIL NUTS

BOTANICAL GAZETTE, LXXII PLATE IX

SPENCER on BRAZIL NUTS

BOTANICAL GAZETTE, LXXII Ad EX:

SPENCER on BRAZIL NUTS

PLATE XI

BOTANICAL GAZETTE, LXXII

SPENCER on BRAZIL NUTS

BOTANICAL GAZETTE, LXXII

PLATE XII
ey 7 i \ 5 S Costes 7

relat =

. SCsy) |» Laas
: 51 a
sito a(eelefeye
C0) A

——

SPENCER on BRAZIL NUTS

GROWTH RINGS te A MONOCOTYL
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 285
CHARLES J. CHAMBERLAIN
(WITH SIXTEEN FIGURES)

The principal object of this paper is to announce the discovery
of growth rings in a monocotyl, but some observations upon growth
rings in other plants may not be out of place. The most familiar
example of periodic growth is seen in the annual rings of Gymno-
sperms and dicotyls; but even when there is a strong tendency to
form only one ring every year, there are numerous variations,
especially when the rings are very wide.

In Melia azedarach the annual rings are often more than a centi-
meter in width, but it is common to find in each season’s growth a
dozen or more secondary rings which are easily seen with the naked
eye. The part of the ring formed in the spring and summer is
quite sharply differentiated from that formed in the autumn, and it
is in this autumn wood that the secondary rings are most con-
spicuous. In the spring and summer wood the few rather indefinite
secondary rings are due to varying proportions of tracheae and
tracheids. The tracheae of summer wood are not very different
from those of early spring; while in the autumn wood the larger
cells merely start to develop into tracheae. They have transverse
walls, which in some cases begin to break down, but here the
development ends. The tracheids of the autumn wood are numer-
ous and very thick-walled, so that this part of the ring is extremely
hard. It is evident that the secondary rings are due to periodic
acceleration and retardation of growth, which causes them to show
some of the features characteristic of ordinary annual rings.

Casuarina tenuissima affords another instance of numerous rings.
A shoot about 3 mm. in diameter and only a few weeks old showed
five or six well marked rings, due to an alternation of tracheae
and tracheids. The plant from which the shoot was taken was

293] [Botanical Gazette, vol. 72

294 BOTANICAL GAZETTE [NOVEMBER

growing in the greenhouse, and the number of rings corresponds,
roughly, to the number of times the plant was watered thoroughly.
Several years ago, in the neighborhood of Jalapa, Mexico, where it
is rather rainy throughout the year, a species of Piper was noticed
which showed no growth rings; while the same species, a few miles
farther east, where there is a sharp alternation of wet and dry
seasons, showed the anticipated rings. These are examples of
immediate response to rather slight changes in conditions. At
the other extreme are plants which show no response to seasonal
conditions, but nevertheless are susceptible to stronger stimuli.

Interesting growth rings which do not mark the number of
years, but correspond to longer intervals, are found in the cycads.
Dioon edule, after a period of coning or after damage by fire, loses
all its leaves and goes into a prolonged resting stage which may last
for several years. When it resumes activity and produces a new
crown, a vigorous growth of wood takes place, with the formation
of large tracheids, which, following the small tracheids of the
nearly exhausted condition, produce a ring having the characters
of an ordinary annual ring in Gymnosperms. These prolonged
resting periods occur at long intervals, so that the number of rings
would be of slight value in estimating the age of a plant. A
section of the trunk of a specimen of D. edule-1.5 to 2 m. in height
would enable one to estimate the interval between successive
growth rings, since the approximate age of the plant could be
determined; but at present it is not easy to secure such a section.
In D. spinulosum the rings look like those of D. edule, but a ring is
produced with the formation of every crown of leaves. Since
crowns in this species are usually formed every other year, the
number of rings indicates about half the age of the plant. In these
cases the ring is a response to a change in conditions, but a very
decided change is necessary to produce the result.

It has long been known that some arborescent monocotyls,
like Dracaena, Yucca, and Aloe, produce a distinct zone of secondary
tissue surrounding the primary and derived from a meristematic
region showing the characters of cambium. In 1912, while study-
ing cycads in South Africa, I cut into a large plant of Aloe ferox

1921] CHAMBERLAIN—GROWTH RINGS 295

to get material for demonstration purposes, and it was surprising
to find growth rings so conspicuous that they could be seen where
the stem was cut with an ax. Pieces to show both primary and
secondary structures were preserved in formalin, and later Aloe
pleuridens, A. ciliaris, and Dracaena Hookeriana were collected
for comparison.

Fic. 1.—Aloe ferox at Cathcart, South Africa, January 1912; about 3m. in
height.

Aloe ferox in the field presents a picturesque appearance,
looking as if an Agave had developed a tall trunk (fig. 1). It
is associated with other xerophytic plants as bizarre as itself,
among them tree forms of Euphorbia more than a dozen meters in
height, species of Encephalartos, and others not so large but equally
peculiar. Most of the material was collected near Grahamstown,
South Africa, in January 1912, from a stem 15 cm. in diameter and
about 3m. high. In transverse section the zone of secondary xylem

f
A
ai)

tf
i
L

Lf”)
e

6
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oe
Cd

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oo
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oy
orn
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oe
UT

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H
ve

Bae a
ee Owes
bY) ei
woe? q tomer

Fics. 2, 2a.—Fig. 2, Aloe ferox, transverse
section of part of stem: s, secondary cortex;
pc, primary cortex; r, outer region of cells
cut off by bi 1 contain

ium; x*, region of secondary bundles; »,
primary polystelic region.

BOTANICAL GAZETTE

[NOVEMBER

was 2 cm. and the cortex
4 mm. in width; so that the
central region, nearly 10 cm.
in diameter and consisting of
primary structures, gave the
whole section somewhat the
appearance of a large pith
surrounded by a narrow zone
of wood and a scanty cortex.

The general topography of
a small portion of a trans-
verse section, natural size, is
shown in fig. 2a. In the pri-
mary region (p) the bundles
are large and scattered, as in
a cornstalk; while in the zone
of secondary growth («?) the
vascular bundles are so reg-
ularly arranged, that to the
naked eye they form a pat-
tern like the chasing on a
watch. The cambium (c),
which is giving rise to sec-
ondary bundles, the second-
ary cortex (s), and some of
the primary cortex between
these two zones of secondary
growth, are also visible to the
naked eye.

The phellogen, with the

secondary cortex produced by

it, the inner cambium with its
derivatives, and also the pri-
mary cortex (pc) between the
two secondary products, are
shown in fig. 2. The walls
of the secondary cortex are

1921] e CHAMBERLAIN—GROWTH RINGS 207

slightly thickened, but thoroughly suberized. Beneath the second-
ary cortex is the primary, consisting of loose rounded cells with

Fics. 3~5.—F1c. 3, Aloe ferox: normal bundle of primary polystelic region; X 100;
fig. 4. Aloe ferox: bundle of primary polystelic region, showing clogged lumen of
tracheids; {some of cells immediately surrounding bundle becoming meristematic;
100; fig. 5, Aloe ferox: more advanced condition than in fig. 4; Xz1o00.

298 BOTANICAL GAZETTE » [NOVEMBER

cellulose walls, and between the primary cortex and the primary
polystelic region is the zone which contains the secondary vascular
bundles and shows the growth rings.

The primary polystelic region, in transverse section, looks
somewhat like an immense cornstalk, with large bundles toward
the center and smaller ones at the outside; but the structure of the
individual bundles is very different from that in corn, for the
bundles in Aloe have no sheath and most of them are completely
amphivasal. There seem to be two types of vascular bundles in

*
el @,
ee:

Fic. 6.—Aloe ferox: showing both types of primary bundles; 100

this primary region. In one type the bundles have normal xylem
and phloem, except that the phloem has very few companion cells
(fig. 3). The other type is peculiar. The phloem begins to dis- .
organize and finally disappears, while the lumen in both tracheids
and vessels becomes clogged with the same material found in the
disorganizing phloem. Some of this material can also be seen
surrounding the bundle itself. An early stage, shown in fig. 4, and
a later stage, shown in fig. 5, are characteristic. In the latter
figure the contents of the xylem cells are much denser and the
phloem cells have become almost indistinguishable, while the
adjacent thin-walled parenchyma is crowding into the space left
vacant by the disorganizing phloem.

1921] CHAM BERLAIN—GROWTH RINGS 299

Another peculiar feature of the bundle with disorganizing
_ phloem is the appearance of vigorous meristematic activity in
the cells surrounding the xylem. These cells behave like a cam-
bium, so that rows consisting of as many as eight cells may be
formed (figs. 4, 5). If differentiation should take place, we should
expect to find a xylem zone and, perhaps, phloem surrounding
the primary bundle; but
development stops soon after
the stage shown in fig. 5, be-
fore any lignification can be
detected. The distribution
and general appearance of the
primary bundles are shown in
fig. 6.

That the secondary growth
in some monocotyls, like
Yucca, Dracaena, and Aloe,
results from meristematic
activity is well known. The
piece of a transverse section
of Aloe ferox, natural size
(fig. 2a), already referred to,
and a somewhat magnified
view of the origin of second-
ary structures (fig. 2), show
the position of the structures 9 10
to be described. The phel- Fics. 7-10.—Alve pleuridens: four early
logen is evid ently hyp odermal 528° in development of secondary bundle;
in origin, and it builds upa
limited amount of secondary cortex, with rectangular cells in
regular rows abutting upon the smaller spherical cells of the
primary cortex. The cambium which gives rise to the vascular
structures is pericyclic in origin, and, as seen in transverse section,
gives rise to long rows of cells. The cells on the outer side of the
cambium undergo comparatively little differentiation; they enlarge
to about twice the size of the cambium cells, and many of them
become almost entirely filled with needle-shaped crystals of calcium

Lena

300 BOTANICAL GAZETTE [NOVEMBER

Fics. 11-13.—Aloe ferox: fig. 11, trans-
Vv secondary bundle; fig. 12
longitudinal radial section; fig. 13, longitu-
dinal tangential section; X 100.

rse section of

oxalate; but the cell walls
thicken very little and retain
the cellulose reaction (fig. 2 7.)

The cells formed centri-
petally from the cambium
give rise to the secondary
woody structures which show
the growth rings. The devel-
opment of the bundle was not
studied very thoroughly in
Aloe ferox, but the early
stages are about the same as
in A. pleuridens. As seen in
transverse section, a cell of
the row produced by the cam-
bium divides, the two result-
ing cells divide, and the
process continues until forty
or fifty cells are formed (figs.
7-10). Differentiation of the
young cells of the vascular
strand begins to take place
before the full number of cells
has been reached. These
bundles are completely am-
phivasal and there is no
sheath of thick-walled cells.
The phloem is scanty and
companion cells are rare.
There is no degeneration or
clogging of the lumen in the
secondary bundles, and there
is no meristematic activity in
any of the surrounding cells,
like that which characterizes
many of the bundles of the
primary cylinder. Since the

1921] CHAMBERLAIN—GROWTH RINGS 301

bundle is completely amphivasal, there is no cambium between the
xylem and phloem, like that found in the primary bundles of many
monocotyls (fig. 11).

The xylem consists almost entirely of tracheids with bordered
pits and with walls so thick and hard that sectioning is difficult.
The cells cut off from the inner side of the cambium and not taking
part in the formation of the bundles keep, more or less perfectly,
their linear arrangement. They are short, somewhat rectangular
in radial view, and are arranged in very definite rows (fig. 12).
The tangential arrangement is not so regular (fig. 13). While
they thicken only a little, they become thoroughly lignified and
extremely hard, so that they
add to the difficulty of cutting
sections. They are marked
by numerous small simple
pits.

The growth rings consti-
tute the most striking feature
of the stem. Der Bary, in his
Comparative anatomy of vege-
tative organs of the phanerogams and ferns, remarked that, while there
seemed to be no reason why growth rings should not be formed in
woody monocotyls, none had ever been observed. An examination
of the literature of vascular anatomy failed to yield any account of
such rings; but, to make certain that nothing had been overlooked,
I wrote to Professor JEFFREY, and he not only informed me that
such rings had never been reported, but also gave some suggestions
which greatly facilitated the investigation.

To the naked eye the growth rings are obvious, but under a
16mm. objective no one would suspect their presence. In Dioon,
where growth rings are obvious to the naked eye but not so
conspicuous under the microscope, the rings are due to the fact
that cells formed at the close of a growth period are somewhat
smaller and have thicker walls than those formed when growth
is resumed. In Aloe ferox the explanation is not so evident. An
examination of fig. 14, showing three thick transverse sections,
indicates that the rings can be seen, even in a half-tone reproduction.

Fic. 14.—Aloe ferox: three thick trans-
verse sections of stem; natural size

302 BOTANICAL GAZETTE [NOVEMBER

The rings can be seen more clearly by looking across the figure
from nearly the level of the paper. The negative was made twice
the size of the section, and the illustration reduced to natural size.
The same sections without reduction are shown in fig. 15. The
appearance, under a low magnification, is shown in fig. 16, which
includes six of the growth rings. The rings are not at all con-
spicuous, and the number of rings probably could not be counted in
the illustration. Even with the position on the rings marked with
the numerals 1-6, they are not easily identified. Two structural
features cause a ring. At the close of the growing: period a few

Fic. 15.—Aloe ferox: from same negative as fig. 14; X2

smaller bundles at irregular intervals are probably responsible, but
the principal cause is that the parenchyma cells formed at the close
of a growing period are slightly smaller and have slightly thicker
walls.

I wrote to Professor SCHONLAND, Director of the Albany Museum
at Grahamstown, South Africa, and to Mr. E. E. Garry, formerly
of Queenstown but now of Naboomspruit, Transvaal, South Africa,
inquiring about climatic conditions in the localities from which
the material was secured. Professor SCHONLAND, to whom I
am also indebted for material of Aloe ferox, wrote as follows:

here are two maxima of rainfall, in October and November, and in
March and April; but this comes out only when the averages of a number of
years are worked out and give a wrong picture of the relation of the flora to
our rainfall. It is true that the winter, from the middle of June to the middle
of September, is generally dry; but I have known good rains in these three
months. Last year (1920) the October-November rains failed us; we had

1921] CHAM BERLAIN—GROWTH RINGS 303

good rains at Christmas, then drought to the middle of March, and then
good soaking rains. The yearly amount of rainfall is often very interesting.
2

hours. The long and short of it is that we live in what might be called the
fag end of the summer rain area; but it can best be described as an area of
uncertain rains.

tf
ie

if
&,
e 5

Fic. 16.—Small portion of region of secondary bundles, including six growth rings,
numbered 1-6; °

Mr. GALPIN replied as follows:
Around Grahamstown and the coastal districts generally, the
very Seiten with no winter frosts and the rainfall fairly equally distributed
throughout the year. Like the whole of South Africa, they have their lean

period of prolonged drought or of oe G rains. These remarks apply to
Cathcart as well, but in that district, with an altitude of about 4000 ft., the
seasonal changes are greater, ith summers and frosty nights in winter.

304 BOTANICAL GAZETTE [NOVEMBER
The rainfall is also very much greater in summer than in winter, although

the tropics. They get a certain amount of rain during the winter months,
while at Naboomspruit, with an annual rainfall of 25 inches, usually not a drop
falls from the end of April to the beginning or even the end of October.

These two accounts, written by botanists who have made a
prolonged study of the South African flora, show that the climatic
conditions in the region where Aloe ferox grows are somewhat
erratic. Large specimens were seen at Junction Farm in the
Transkei, near Cathcart, and the negative from which fig. 1 was
made was taken on the Windvogelberg, overlooking the town of
Cathcart; but no material was collected. Judging from Mr. GAL-
PIN’S account, specimens from the Windvogelberg would show
more sharply marked rings than one would be likely to find in
plants from the Grahamstown region where this material was
collected. Both accounts, however, would lead one to expect the
irregularities which appear in the rings of material collected near
Grahamstown. Irregularities may be seen in figs. 14 and 15,
and in fig. 16, where the position of the six rings is marked by the
numerals 1-6.

Whether other species of Aloe would show rings or not could be
determined very easily by one who is within reach of material. A
few slides of A. pleuridens show a couple of faint rings. Dracaena
Hookeriana, collected at East London, less than 100 miles south
of Cathcart, shows secondary wood but no growth rings. It would
be interesting to see the condition in Aloe Bainesii, the trunk of
which may reach a diameter of a meter in less than thirty years.
A specimen of Yucca with a zone of wood a centimeter in diameter,
growing in the greenhouse, showed no growth rings; but such rings
could hardly be expected in a greenhouse, where conditions are so
uniform. One wonders whether the failure to find growth rings
in woody monocotyls may not be due to the fact that they are.
mostly tropical and subtropical, out of the University zone, s0
that observations are likely to have been made upon greenhouse
material. That there are growth rings in Aloe ferox is beyond
question, and this is believed to be the first account of such rings
in any monocotyl.

UNIVERSITY OF CHICAGO

INVASION OF VIRGIN SOIL IN THE TROPICS!

Duncan S. JoHnson
(WITH TWO FIGURES)

This note is concerned with the revegetation of a tropical valley
which was denuded of plants by a flood and later filled with detritus
from a landslide. Acknowledgments are due to Messrs. H. A.
GLEASON, Wittiam Harris, M. A. Howe, E. P. Kui, W. R.
Maxon, and Percy Witson for the identification of plants collected
in the Cascade Valley; to E. P. Kriire and Wi1aM Sereriz for
‘taking photographs of the valley; and to Jonas WALKER, a
Jamaican collector, for gathering plants growing in the valley in
December.

The Blue Mountain region of Jamaica was subjected, in Novem-
ber 1909, to several days of nearly continuous torrential rains, such
as apparently occur there only once or twice in a century. On
November 8, 1909, there was a rainfall of 18.3 inches in 24 hours
at the Cinchona Station, and this downpour continued into the
next day, until 27 inches had fallen. The rainfall was undoubtedly
heavier still on the higher peaks of the Blue Mountains which
drain into the valley under discussion.

The floods arising from these tremendous rains caused striking
changes in the topography, and in the plant covering of many con-
siderable areas on both the north and the south sides of the Blue
Mountains. In the first place, many small streams rose two or
three meters above the normal level, and scoured their rocky
banks clean of vegetation, aside from larger trees, for many meters
on either side. In the second place, there were landslides from
the wooded mountain sides, and especially from the cultivated
coffee fields, which completely carried away soil and vegetation
from scores of acres on the south side of the mountains. These
landslides not only left great scars, showing the bare rock on the
formerly tree-covered mountain sides and in the coffee fields

* Botanical contribution from the Johns Hopkins University, no. 70.

395] {Botanical Gazette, vol. 72

306 BOTANICAL GAZETTE [NOVEMBER

lower down, but they also filled in whole valley bottoms with the
rock and gravel washed down from above. The amount of water
and of débris carried with it was sufficient to wash away or bury
out of sight most of a large and substantially constructed stone and
concrete “‘coffee works” near the Cascade River.

The effect of the flood and landslides on the topography and
vegetation of the valley of the Cascade River, a normally small
mountain stream, located about three miles east of the Cinchona
Botanical Station, was briefly described in a note published in
tg10.2, At that time, which was but six months after the flood,
the floor of this valley was still a barren waste, covered with
pebbles and broken rock fragments of all sizes, ranging from that
of a pea up to bowlders a meter in diameter. The only plants
evident at this time were a few widely scattered seedlings of Bocconia
frutescens and still fewer seedlings of half a dozen other dicotyledons,
such as grow on the hills beside the valley. The largest of these
plants were only 2 or 3dm. high. - In other words, the valley
bottom, which in 1903 and 1906 I had seen covered with a forest
consisting of large trees together with dozens of types of shrubs and
herbs, was in 1910 an all but absolute desert. The forest had been
completely .washed away or buried, and there was left a truly
virgin soil, with no trace of humus, which bore but the barest
sprinkling of young seedlings.

After studying the conditions in this and other valleys in 1910,
and taking into account the abundant rainfall and frostless climate
of the region, it was concluded that the floor of the Cascade Valley
would probably be recovered with a dense vegetation, although
perhaps not with a fully developed forest, in a score or two of years.
It was realized, of course, that many of the forest plants, being
dependent on an abundant humus, would not find satisfactory
conditions there for many years, because of the slowness with which
this type of soil is developed.

On a trip to Jamaica, in July 1919, I again visited the Cascade
Valley, and expected to find that, during the nine years that had
elapsed, the few plants that were starting on the newly deposited
gravel in 1910 had multiplied greatly, and that many new species

2 Jour. New York Bot. Gard. 11:273. 1910.

1921| JOHNSON—VIRGIN SOIL e 307

would be establishing themselves among those first invaders.
Many of the possible invaders of the valley, found on the neighbor-
ing hills, have a long growing season. Thére are some species that
grow actively from February to September, while still others
grow practically throughout the whole year.’ Because of this
long growing season and the possibility of some humus washing
down from the surrounding hills, it was assumed that by 1919
the soil of the valley floor would be well hidden by a plant covering.

—Looking east across Cascade Valley, gual sparse vegetation, which
fe ae is caisk be still more evident if viewed from abov

My surprise was great, therefore, when I found hardly more than
a tenth of the gravelly bottom of the Cascade Valley hidden by
plant foliage. The soil between these leafy plants, it is true, was
not absolutely bare. There were a few very small patches of
lichens and mosses. There was also a chroococcaceous alga,
Gloeocapsa magma, which formed smooth encrustations often
several square decimeters in extent on the pebbles and bowlders.
This alga is present not only near the streams but across the whole
floor of the valley. When dry Gloeocapsa has a rather dirty or
chocolate brown color, but when wet it becomes a glistening velvety
layer of a dark maroon color. It evidently thrives on these bare

3 SHREVE, F., Publication no. 199, Carnegie Inst. Wash. pp. 51-52. 1914.

gee BOTANICAL GAZETTE [NOVEMBER

rocks, although they may often be exposed to a scorching sun for
many hours daily and be without rain for days or even several
weeks together. There 4s a copious dew in the valley each clear
night, however, while on cloudy nights the fog probably condenses
on the rocks and plants of its floor. It is likely that Gloeocapsa
may thus be able to carry on photosynthesis and growth for some
hours each day, even without rain.

The bareness of the valley bottom recalled that of the more
barren of the stony deserts of Arizona as they appear in early
summer. The general aspect of this valley differed from that of
these deserts in the absence of cacti and of all larger woody plants.
No plants of this valley exceeded a meter or two in height except
where, at the very edges of the valley, considerable top soil, that
had washed down from the hillsides, afforded better conditions for
plant growth. Here several species of shrubs grew to two or three
meters in height, and in wetter soil considerable stands of Arundo sp.
had established themselves (fig. 1, x). The shrubs and cane
together made a conspicuous verdant border to the generally desert-
like valley floor.

When the floor of the valley, especially the portion along the
trail from the junction of the Cascade and Green rivers to Farm
Hill Coffee Works, was more carefully examined, the scattered
vegetation was found to include the following plants:

ALGAE . DIcoTYLEDONEAE
Gloeocapsa magma (Breb.) Kiitz. Piper sp. ? (shrub or tree)
Pilea microphylla L. (Liebm.) (annual
to perenni
Iresine celosioides L. (half shrubby)
Begonia acuminata Dryand. (half

PTERIDOPHYTA shrubby)
Dryopteris sligophylla Maxon Asclepias curassavica L. (perennial herb)
Blechnum occidentale L. Asclepias nivea L. (perennial herb)
oe tartarea (Sw.) Philibertella clausa (Jacq.) Vail (shrubby
Des vine)
Trismeria trifoliata (L.) Diels Duranta plumieri Jacq.(shrub 2-3 meters)

Pityrogramma calomelaeana (L.) Verbena bonariensis L. (perennial herb)

Link anum torvum Sw. (half sh rubby)
Pteris longifolia L. Maurandia scandens A. Gr. (shrubby
Aneimia adiantifolia (L.) Sw. vine)

r92t] JOHNSON—VIRGIN SOIL 309

Ageratum conoyzoides L. (annual)
Ageratum houstonianum Mill. (annual)

MoNnoCOTYLEDONEAE Vernonia acuminata Less. (half shrubby)
Arundo (saccharoides Gr. ?) Vernonia permollis Gleason (half shrubby)
Mikania scandens L. (Wild.) (shrubby

vine)

Eupatorium triste DC. (half shrubby)
Baccharis scoparia Sw. (shrubby)
Pluchea odorata L. (Cass.) (half shrubby)
Bidens incisa Ker. (annual)

Senecio discolor (Sw.) DC. (shrubby)

There were thus seven species of ferns, of which Dryopteris oligo-
phylla, Blechnum occidentale, and Aneimia adiantifolia were rare,
less than a score of each being seen where we crossed the valley.
Pityrogramma calomelaena and Gymnogramme tartarica were more
frequent; while Trismeria trifoliata was represented by dozens of
specimens in the moister soil, and of Pteris longifolia there were
still more numerous clumps in the drier spots along the trail across
the valley. From the size of many of the fern plants seen it seems
clear that they have been established for some time. In the cases
of Gymnogramme and Trismeria, where fronds a meter high were
seen, it was hard to believe that such plants could have arisen
from a prothallus in nine years. Yet they must have done so
unless it is assumed that old rhizomes have persisted in the soil
to push up through the gravel, or that pieces of rhizomes have
been washed down by the flood of 1909 or subsequent lesser ones.
The first supposition seems negatived by the fact that no ferns were
seen in 1910, six months after the flood, and also by the fact that
each clump of a fern consists of but one or a few branches and
leaf clusters. This latter feature tends to confirm the impression
gained from the character of the soil, namely, that these ferns
have started in situ from prothallia.

All the seed plants found in the valley, except Arundo along
the stream at the foot of the cliff, were dicotyledons. By far
the most important of these was the composite Vernonia permollis.
Scores of clumps of this, from quite young plants up to those 2 m.
high, were found scattered across the valley. They grew beside
the larger rocks and often also formed rather definite rows along

310 BOTANICAL GAZETTE [NOVEMBER

the small dry gullies, which during the rainy season drain the
raised middle of the valley floor that lies between the main stream
on the west and the branch stream that comes in from the east.
This ironweed is the most prominent plant of the valley, not only
because of its abundance but also from its size. It is this plant,
for example, that forms the major component of the clumps shown
in fig. 1. The three more prominent plants after Vernonia permollis
are Bocconia frutescens (already grown to 2 or 3m. in height),
Solanum torvum Sw. (often 2m. high), and Vernonia acuminata

2.—Looking north over upper Cascade Valley, showing scars left on south
side of Blue Mountains by landslides.

(about 2 m). These larger plants are sometimes mingled with the
Vernonia permollis, although much fewer than the latter, but may
also be scattered sparingly by themselves over the valley floor.

Of the less prominent seed plants of the valley; some fifteen
species were found. These, with their relative abundance, are:
Piper sp.? (two or three young plants), Pilea microphylla L.
(Liebm.) (rather frequent), Iresine celosioides L. (sparse), Begonia
acuminata (very few), Asclepias curassavica L. and A. nivea L. (both
infrequent), Philibertella clausa (Jacq.) Vail. (a dozen plants seen),
Duranta plumieri Jacq. (half a dozen plants), Verbena bonariensis
L. (few), Solanum torvum Sw., Maurandia scandens A. Gr. (occa-

1921] JOHNSON—VIRGIN SOIL 311

sional at edges of valley), Ageratum conyzoides L. and A. houstoni-
anum Mill. (rare), Mikania scandens L. (Wild.) (infrequent),
Eupatorium triste DC. (few), Baccharis scoparia sp. (a dozen or so),
Pluchea adorata L. (Cass.) (not infrequent), and Bidens incisa Ker.
(frequent). All of these plants, with the possible exceptions of the
Pilea and Bidens, were far less abundant than any of the four
species mentioned in the preceding paragraph. Most of these
fifteen plants are also smaller species, which likewise makes them
less conspicuous in the vegetation of the valley. The Duranta,
Solanum, and Baccharis are now as large as the species of Vernonia,
but not asnumerous. The climbing forms Philibertella, Maurandia,
and Mikania of course are rather long, having already reached and
spread over the tops of the largest plants near them. Many indi-
viduals of these fifteen species, as for example those growing in
unusually dry situations, were dwarfed, and thus showed by their
stunted form that they were not finding optimum conditions in
the sterile soil and dry exposed situations afforded by the gravelly
floor of the valley.

It is to be noted that, contrary to the accepted rule for invaders
of new soil areas, as stated by WARMING,‘ the plants now established
in the Cascade Valley are not mostly annuals or biennials. Instead
they are chiefly perennials, and in fact shrubby or half-shrubby
ones. Although this is true, it is to be noted also that not one
arborescent form has yet been found, unless some of the young
plants of Piper seen should prove to belong to one of the more tree-
like species of this usually shrublike genus.

In this area of virgin soil there are present right through the year
all of the climatic factors, such as moisture, heat, and light, that
are needed for the production of a rich vegetation. This is evident
from the dense forest that has developed in the adjoining valleys and
even on the hills immediately overhanging the Cascade Valley
itself. It was for these reasons that the writer was rather surprised,
on revisiting this valley in 1919, at the slowness with which it is
being recovered with vegetation. He was surprised not only at the
relatively small number of new individuals, but especially at the
very small number of species that had established themselves in the

4 Oecology of plants. p. 356. 1900.

312 BOTANICAL GAZETTE [NOVEMBER

decade. It was anticipated in 1910 that certain plants which
require abundant humus would not be able to settle at once on its
bowlders and gravel, nor could epiphytes soon find the necessagy
trees to perch in. That the many mosses, ferns, and seed plants
that grow all about the valley, not only in similar gravelly and stony
soil along the trails, but even in the crevices of every rugged cliff
and crag of the neighboring hills, should prove incapable of promptly
and completely colonizing this valley was quite unexpected.

The decisive causes responsible for this slowness of revegetation
have not been determined. It may be remarked in the first place
that browsing by animals is a negligible factor in the development
_of the vegetation, since such animals are not allowed to run free in

this region. Furthermore, it does not seem probable that the
chemical nature of the rock can be the prime cause of this phe-
nomenon. It is conceivable that at a later stage the soil formed
by disintegration of the rock, which is an epidosite (or epidote
gneiss), may determine the types of micro-organisms living in the
soil and so the kinds of humus produced. The fact that a rather
varied series of some thirty species of plants have been able
to establish themselves in this valley shows that the soil, which is
probably of fairly uniform chemical character throughout, is not
especially unfavorable to plants. The distribution of the plants
now growing in the valley seems rather to be related to the physical
character of the soil. Plants are found growing where finer soil par-
ticles have accumulated. Probably the most important hindrance
to the increase of the vegetation is instability of the soil, which,
in most areas of this rather steeply sloping valley, is being con-
stantly changed, by erosion at some points and by deposit at others.

It seems clear that in the future development of the plant cover-
ing of this valley the existing vegetation after a time will establish
more fixed conditions in areas now occupied. This will give the
mycorhizal fungi and soil bacteria, which cannot thrive in this
sterile gravel, a sufficient amount of vegetable matter on which to
feed. There will then probably be a decided acceleration both in
the spread of the plant species now present, and in the introduction
of new species. The writer hopes, during the coming decade, to be
able to study further and to report on the progress of the revegeta-
tion of this valley.

Jouns Hopkins UNIVERSITY

BAL E,

PECTIC MATERIAL IN ROOT HAIRS
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 286
‘CAROLINE G. Howe

It has been observed for some time that many soils show some
acidity, that plants are able to take up much more mineral matter
than can easily be extracted from soil, and also that although
fertilizers are made up of soluble salts, the virgin soils are composed
largely of difficultly soluble salts, and after they have been culti-
vated a few years, yield as full crops if not fuller than those treated
with ordinary fertilizers. This has given rise to the question
whether there may not be something in the structure of the root
hair which enables it to change the difficultly soluble salts to such a
form that they can be dissolved and taken into the plant; and
since root hairs are so ephemeral, any chemical effect they may
have upon the soil will not be present very long in one place.

Since many soils were found to be somewhat acid, and yet most
plants cannot grow in an acid medium, two explanations were
offered for this phenomenon; first, that there was an acid in the
soil which, for lack of a better name, was called humus acid; and
secondly, that negatively charged colloidal particles either in the
plant tissues or in the soil broke up the salts and released the acids
into the soil.

BAUMANN and GULLY (cited by SKENE 6) investigated this
matter with peat and mosses, and found that when put into a
sodium chloride solution, these plants were able to absorb the
positive ion and thus release the chlorine, which, combining with
the hydrogen ion, made hydrochloric acid. SKENE (6) made similar
tests upon sphagnum, using copper chloride solution, and found
that the moss had taken up the copper, releasing the chlorine,
which again formed hydrochloric acid. WxELER (8) also tested
the higher plants, such as the needles of the pine, the leaves of the
horse chestnut, American oak, and yellow lupine, and found that
they were all acid, and concluded that the decaying vegetation
313] [Botanical Gazette, vol. 72

314 BOTANICAL GAZETTE [NOVEMBER

would explain the presence of acid in the soil. Again, ODEN (3)
found in the plants that he examined a gelatinous material of the
nature of pectic acid, and Manern (1) found that pectose is often
formed in young cells before cellulose, and that the middle lamella
is calcium pectate. He (2) also found that pectose can be changed ©
to pectic acid or pectin by gently heating in 2 per cent hydrochloric
acid.

SAMPSON (5), in investigating abscission of the leaf of Coleus,
found that there was calcium pectate in the middle lamella just
before the time of abscission, but that the calcium was lacking at
abscission, and discovered that this was due to the pectic acid
forming so much more rapidly than the calcium was supplied that
the middle lamella was broken down. Miss Roperts (4) also
examined root hairs of a number of seedlings grown in moist air
and found that they all had a layer of pectic material outside the
cellulose wall, and often at the tip of the hair there was a layer of
callose.

In order to determine whether this condition is general, the
root hairs of twenty economic plants grown in sand and in loam were
examined, and those of a few seedlings grown in Knop’s solution.
These seedlings were selected with the idea, first, of getting as great
range as possible, and secondly, of comparing several in the same
or closely related genera. These root hairs were tested micro-
chemically for cellulose with iodine and 70 per cent sulphuric acid,
which turns cellulose bright blue; for callose with resorcin blue,
which causes callose to swell and to turn blue; for acidity with
neutral red (and later with the Clark and Lubs indicators to
determine the degree of acidity); for calcium pectate with ammo-
nium oxalate, which unites with the calcium pectate when calcium
oxalate crystals and ammonium pectate are formed; and for pectic
material in general with ruthenian red. Of the special forms
of pectic material chiefly found in plants, pectose is found
especially in young tissues, is insoluble in water, but can be
changed to pectic acid or pectin by gently heating for twenty
minutes in a 2 per cent solution of hydrochloric acid. Pectin is
soluble in water, and pectic acid is soluble in a 2 per cent solution
of potassium hydroxide when gently heated for twenty minutes.

‘r92t]

HOW E—ROOT HAIRS

TABLE I

RUTHENIAN RED FOR PECTIC MATERIAL, IN
PE ice 2 PER CENT POTASSIUM
OXIDE FOR PECTIC ACID, WHICH IS
DISSOLVED BY IT; 2 PER CENT HYDRO-
CHLORI se

AMMONIUM OXALATE AND

c
TALS AND AMMONIUM
PECTATE

FOR CHANGE OF PECTOSE:
SOLUBLE IN WATER

SEEDS
Test oe oxalate Test for pectic material
_Loam Sand Loam Sand
goed Aen eleey. Many Many Thick layer; pec- aie soot _ changed
i eee crystals crystals tose changed in chie fy,
mostly to yore aby fe pect
acid cid
Beans (Bush lima)..| Few Few Pectose changed | Thin layer;
crystals crystals chiefly to pec- changed chiefly
tin,some to pec-| _ to pectic acid
tic acid; thin
r
Beans (Pole lima)..| Many crys-| Many Thick; pectose | Thick; pectose
tals, es- crystals changed to pec-| changed to pec-
cially tic acid tic acid
in older
roothairs
— (Golden Very few | Very few Se layer; ee Same as in loam
9 a ea ok crystals crystals ose —
pecile ax
Cabbage (Chinese).| Crystals Many Pectose changed | Same as in loam
fairly crystals largely to pectin
abundant
— (Early Very few | Many bore alin Siok Sgt Same as in loam
ee y Wake- crystals changed t
dk aes Seckie pe
Carrot (Danver’s ? ? __ layer; pec-| Same as in loam
half long)... ... chan,
erties acid
ao eben 9 Many Many Thick layer; gt Same as in loam
Se ‘ crystals crystals tose changed to
pectic acid
~~ — Very few | Very few, cori changed | Pectose _ ch
at eee even less 0 pectic acid topectin chiefly,
than in some to i
loam aci
Cucumber (Early | Almost no | Almost no {| Thin layer; pec- ll ag
fottume).: 5-3 crystals crystals tose changed tose chan,
mostly to pec- mostly to <a
in, some to pec-
‘ tic aci

BOTANICAL GAZETTE

TABLE I—Continued

[NOVEMBER

AMMONIUM OXALATE AND
CALCIUM PECTATE FORM
CALCIUM OXALATE CRYS-
TALS AND AMMONIUM
PECTATE

RUTHENIAN RED FOR PECTIC MATERIAL, IN
Panna 2 PER CENT POTASSIUM

E FOR PECTIC ACID heed Rey

OXID:
geben po BY IT;

2 PE

R CE
CHLO: — ACID FOR chimes OF gles rari
CTIN SOLUBLE IN WATER

SEEDS
Test oe oxalate Test for pectic material
Loam Sand Loam Sand
Egg pent (Black | Many Many Thick layer; ger Same as in loam
beauty) oo. crystals crystals tose changed to
pectic acid
pape (Mignon- | Few ny Pectose changed _ | Same as in loam
HE} ck ers oss crystals crystals chiefly to pectic
pecial-
ly near
P
phages i (Hollow Very few Very few | Pectose changed | Same as in loam
Wi) ole. es crystals crystals chiefly to pectic
acid
Peas (Telephone)..| Many Many, on ape Fy Same as in loam
crystals crystals 0 pectic acid
Radish (Sparkler)..| Many Many sei tia Fag Same as in loam
crystals crystals 0 pectic acid
saecwd One aly Many Many Pectose changed | Same as in loam
cc AS crystals crystals chiefly to pectic
; acid, some to
pectin
agape (Giant Number of | Number of |Pectose changed Little A ai acid:
ummer crook crystals crystals to pectic acid pecto: oc
ood cK)... to eet acid
Swiss Chard Few Few hig cepry Some Pawn! acid;
(Lucullus)..... crystals crystals 0 pectic acid pectose cha nged
to pectic acid
Tomatoes Few | Few Pectose changed Epon layer; pec-
(Ponderosa).....} crystals crystals to pectin wage a to
nie ic
Watermelon Many Many Some pectic acid; | Same as in loam
(Cole’s early)..| crystals crystals pectose changed
to pectic acid

In general, the root system was
seedlings grown in sand, and the

found more extensive on those
root hairs were much longer.

1921] HOWE—ROOT HAIRS 3t7

It was also more difficult to find the young root hairs on the roots
grown in sand. Pectic material was found in the outer layer of all
the root hairs; some of it was in the form of calcium pectate in
practically all the root hairs, much was in the form of pectose, and
it was difficult to determine with certainty whether some was in the
form of pectic acid. By the application of 2 per cent hydrochloric
acid the pectose was changed to pectic acid except in a few instances
when some was changed to pectin, and the calcium pectate was
broken down to calcium chloride, allowing pectic acid to be set
free. Why pectose is changed sometimes to one form and some-
times to the other is still an unsolved problem.

Callose forming an inner lamella of the wall was found in all
the root hairs, being somewhat thicker at the tip, especially of the
younger root hairs. The hairs grown in the two media did not
differ essentially in these respects, except that ‘the callose was
somewhat thicker at the tips in loam than in sand. No cellulose
was found in the root hair walls. As the root epidermal cell
bulges to form a hair, the cellulose inner lamella apparently stretches
to its capacity, then breaks, and no more cellulose is formed. It
may be that under other conditions more cellulose would be formed.

‘The root hairs gave an acid reaction in all cases both in the
loam and in the sand, but usually somewhat higher in the loam
than in the sand. According to the P,, value, they ranged between
6.8-6.0 in the sand and in the loam, and in some cases in loam
between 6.0-5.2.

The seedlings of only four species were grown in Knop’s solution,
and the hairs were quite numerous and symmetrical. Before the
seeds were placed for germination in the Knop’s solution, it was
tested and found to have an acidity of 6.8-6.0. After the seedlings
had grown, both the root hairs and the solution were tested for
acidity. The root hairs showed about the same degree of acidity or
a little less than that of the root hairs grown in the soil, while the
solution was also less acid than the original, even becoming alkaline
in three of the cases. These root hairs had the same structure as
those grown in loam and sand, except that the callose was thicker
at the tips and in two of the cases the pectose was changed to
pectin

BOTANICAL GAZETTE

TABLE II*

[NOVEMBER

RESORCIN BLUE CHANGED CALLOSE TO BLUE

Acrpity, Px VALUE, BY USE
oF CLARK AND Luss’

INDICATORS
_ Callose Acidity
Loam Sand Loam Sand
ro sey Thick layer, espe-| Thick layer, espe-| 6.0-5.2 6.0-5.2
Mer ser ially on young cially on young
hairs hairs
Beans (Bush lima).| Thick layer Thick layer 5.2 6:075.2
Beans (Pole lima). .| Thick lay: Thick layer 6.0-5.2 6.0-5.2
Beans (Golden Fairly thick layer,| Thick layer Roe 6.8-6.0
WA eco especially on
young hairs and
tip
Cabbage (Chinese).| Thin laye Thin layer 6.8-6.0 6.8
Cabbage (Early Thin a. found] Same asin loam | Nearer 6.0] Nearer 6.8
Jersey e- on young root
held) 9.20523 pecially
Carrots (Danvers).| At ft only, in Thick in older 6.0-5.2 6.0-5.2
g hairs hairs
fie ‘all around|
Corn haces Rew haghatt , espe- | Same as in loam 4.6-4.4 6.0-5.2
tai). cs
=e Thick iw Thin layer 6.0-5.2 | 7.6-6.8
pres (Early | Thick layer Thick layer 6.0-5.2 6.8-6.0
Egg plant (Black | Thick layer, espe-| Thick layer 6.0-§.2 6.0-5.2
; cially at ti
a (Mignon- On younger hairs | Same as in loam 6.0-5§.2 6.0-5.2
SE Ee especially
aren (Hollow Thick layer, espe-| Same as in loam 6.8-6.0 7-6-6.8
CrOWN) <2 2. cially at ti
Peas (Telephone). .| Thick la jess layer ? 6.0-5.2
Radish (Sparkler)... — but el Layer at tip 6.8-6.0 7.6-6.8
airs
Squash (Golden Thick $i thick- Thin layer, thick-| 6.0-5.2 6.8-6.0
Hubbard). ..... er at er at tip
Squash (Giant Thin si Fairly thick layer| 6.0-5.2 6.8-6.0
oor crook-
Swiss Chard _ Frsgtink thick-| Same as in loam 6.0-5.2 6.8-6.0
(Lucuthis)..._-.
Tomatoes Thick layer, snc Same as in loam 6.0-5.2 6.0-5.2
(Ponderosa)... .. cially
atermelon Thick layer, espe-| Same as in loam 6.0-5.2 6.8-6.0
(Cole’s early)...| cially on young

From these experiments it would seem that some of the acidity
of the soil is due to pectic material in the root hairs,

and that this

1921] HOWE—ROOT HAIRS 319
may help change some of the difficultly soluble salts, such as

tricalcium phosphate, to a soluble form that can be used by the
plant.

TABLE IITI*
SEEDLINGS GROWN IN KNop’s SOLUTION
AMMONIUM OXALATE| RUTHENIAN RED FOR PECTIC
AND CALCIUM PEC- MATERIAL, IN GENERAL}
TATE FORM 2 PER CENT HYDROCHLORIC
CALCIUM OXALA ACID FOR CHANGE OF PEC- greening
CRYSTALS AND TOSE; 2 PER CENT POTAS-
SEEDS AMMONIUM SIUM HYDROXIDE FOR
PECTATE PECTIC ACID
Test for calcium Test for pectic material Test for callose
: oxalate crystals
Cabbage (Early Jersey

Wakefield) .

Many crystals | Thick layer all around;} Thick layer;
pectose changed thicker at tip
e

Seem (Early for- | Few crystals Thick layer; pectose| Very thick layer
Re) eS, oes changed to pectic acid| all round
bi to pectin at
Radish (Sparkler)... ... Many crystals Pertais changed to pec-} Thick layer, es-
tic _ - td to pec-|_ pecially at tip

tin

Muskmelon (Rockyford)| Few crystals Pectose changed largely — thick
o pectin yer

* Cellulose was not found in any of the root hairs.

TABLE IV
SEEDLINGS GROWN IN KNOopP’S SOLUTION
Actpity, Pu VALUE BY USE OF CLARK
AND LuBs’ INDICATORS
SEEDS
Root hairs Solution
CADbNRE cs a ee 6.8-6.0 7-0-7 .2
MCUMDEr. oe 7.2-6.8 8.4-7.6
atigh oo oe 6.8-6.0 8.4-7.6
Muskmelon. 53065 sc 6.8-6.0 6.8-6.0
Summary

t. No cellulose was found in the root hairs of the species studied.
2. The root hairs grown in both loam and sand have a layer of
pectic material on the outside, and within a layer of callose, thicker

in some plants than in others, and usually a little thicker at the
tips.

320 BOTANICAL GAZETTE [NOVEMBER

3. The pectic material in most of the cases at first is in the form
of calcium pectate or pectose; pectic acid could not be detected
with certainty. The pectic layer is somewhat thicker in loam than
in sand."

4. The root hairs are somewhat acid in the forms studied, and
there is a tendency to be slightly more acid in loam than in sand.

5. Whether the acidity of the root hair can be ascribed to the
presence of pectic material or to some other cause has not been yet
determined with certainty.

Acknowledgement i is due to Dr. SopH1a H. EcKxerson for her
suggestions and criticism during the progress of this study.
East Orance, N.J.

LITERATURE CITED

1. Mancry, M. L., Sur la constitution de la membrane de vegetaux. Compt.
Rend. 107:144-146. 1888.

, Etude historique et critique sur la presence des grey pectiques
dans les tissues des vegetaux. Jour. Botanique 6:12-10.

3. OvEn, S., Ziir Frage der Aciditat der Zellmembranen. ber Denti: Bot.
Gesells. 34:648-660. 1916; Review in Bot. Centralbl. 137:103. 1918.

4. Roserts, Epitx A., Epidermal cells of roots. Bort. GAz. 62:488-505. 1916.

5. Sampson, H. C., Abscission in the Coleus leaf. Bot. GAz. 66:32-53- 1918.

6. SKENE, M., The acidity of peli and its relation to chalk and mineral
salts. Ann. Botany 29:65-87. 1

7. Truoe, E., vee acidity: its hati to growth of plants. Soil Science
5:169-193. I

8. WIELER, A., Die Aciditaét der Zellmembranen. Ber. Deutsch Bot. Gesells.
30: 304-406. 1912.

* The pectose is usually changed to pectic acid by the hydrochloric acid.

DESTRUCTION OF MOSSES BY LICHENS
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 287
FRANK P. MaWroade x
(WITH PLATE XII)

The deep-rooted conception of lichens as typical examples of
symbiosis has induced workers along ecological lines to overlook
the occurrence in xérarch successions of early stages which are
dominated by the parasitism of lichens on mosses. This preliminary
paper is intended to describe certain cases of lichen parasitism,
and to emphasize the accuracy of Frnx’s definition of lichens:
“A lichen is a fungus which lives during all or part of its life in
parasitic relation with an algal host, and also sustains a relation with
an organic or inorganic substratum.”

The writer’s attention was first called to this situation when
trying to separate some Cladonia lichen material from a moss colony
in which it was growing. The intimacy of the mixture suggested
that the lichen might be to some extent parasitic on the moss.
Such phenomena seem to have been noticed previously by Bon-
NIER," who shows that spores of lichens are known to germinate
on moss protonemas and eventually to attack and kill them. He
Suggests the occurrence of such parasitism in nature on a large scale.

Moss-lichen colonies were chosen for study, in which both ele-
ments were intimately mixed, illustrating cases of dominance on the
part of one or the other. It was often impossible to determine
the exact species oreven genus of the mosses concerned, because of
the poor condition of the vegetative body and lack of reproductive
organs. Mosses hampered by invading lichens seldom produce
spores. Representative lichen-moss mixtures consisting of species

* Bonnier, Gaston, Germination des spores des Lichens sur les protonemas
des Mousses et sur des Algues differents des gonidies du Lichen. Compt. Rend.

Soc. Biol. Paris. 40:541-543. 1888.
rmination des Lichens sur les protonemas des Mousses. Rev. Gen.
99.

, Ge
Bot. 1: 165169. pl. 8. 18

321] [Botanical Gazette, vol. 72

322 BOTANICAL GAZETTE [NOVEMBER

of Dicranum, Bryum, Grimmia, or Fissidens with Cladonia, Physcia,
or Amphiloma have been collected. The following species deter-
minations of mosses based on vegetative characters may be taken
as probable: Dicranum scoparium, Bryum caespiticium, B. argen-
teum, Grimmia apocarpa, G. pennsylvanica, and Fissidens adian-
toides. Especially important among the lichens concerned are
Cladonia cristatella, C. baccillaris, C. pyxidata, Physcia stellaris,
P. obscura, and, Amphiloma lanuginosum.

All previous observations along this line are based on cultures
and the examination of teased materials. The method employed
consisted of imbedding and sectioning moss-lichen colonies, the
resultant serial sections giving a veritable moving picture of the
conditions in the colonies. The striking destruction of moss tissues
is evident from sections 10 w or more in thickness, but to judge
the extent and nature of the haustorial action it is necessary to
have sections 3 uw or less in thickness. Many kinds of fixatives
were used to show to the best advantage the various tissues con-
cerned; no one fixative gave the most satisfactory fixation for all.
The fungus elements of the lichen fix well in chromoacetic; the
algal elements in hot bichloride of mercury. The location of the
nucleus in the algal cells, and the condition of plastids in the moss
show well in aceto-formalin. The cell wall structures of all the
tissues showed best in aceto-formalin. Very weak Flemming’s
solution gave excellent results in the young tissues of the moss.
The three tissues, moss, fungus, and alga, can be sharply differ-
entiated by a carefully balanced Flemming’s triple stain. For
wall studies nothing proved better than a contrasting safranin-
analin-blue stain. With this stain the cell wall changes and the
haustorial action may be clearly demonstrated. Slides so stained
were easily photographed by suitable combinations of yellow and
green filters. In addition to the section studies, a long series of
cultures was run with Amphiloma and other lichen genera to see
how readily and under what conditions they would attack a moss
host.

The destructive action of lichens on moss may be seen from
figs. 1 and 2. These were from to p sections of intimate mixtures
of Cladonia lichens with Dicranum, Grimmia, and other mosses,

1921] McWHORTER—MOSSES AND LICHENS 323

in which the moss appears plastered over by the lichens. The apical
development of the moss has been stopped. The lichen hyphae
could be traced through the old moss tissue where they forced their
way intercellularly.

A very constant feature of the lichen growth on mosses is the
clinging of the lichen hyphae to the thickened walls of the moss.
This seems to be of great significance in the eventual destruction
of the moss colony. It is not the meristematic tissue that seems
particularly desirable to the lichen fungus, but the thickenings of the
moss walls. The case seems homologous with the destruction of
wood by a polyporous fungus, where the lignified part of the wood is
especially attacked, and the cellulose walls are left almost un-
touched. In the mosses the young walls are pure cellulose; the
thickenings are of pectin. Thin sections of all the moss-lichen
colonies studied showed the hyphae imbedded in the pectin.
There is no evidence that the hyphae have been covered over by
the forming pectin layers, but it seems obvious that the hyphae
have taken their position by dissolving out the pectin. The
figures of Amphiloma on Grimmia show a case of this, but
Amphiloma is more destructive than most lichens, and in places
has completely destroyed the moss. When sharply stained in
safranin and analine blue, the pectinized part of the walls stains a
strong red, so that penetration of the bluish stained hyphae may
be plainly followed. In some colonies, even when the lichens
appear to be literally plastered over the mosses, the lichen hyphae
were found to be confined to the pectinized regions, and the cellulose
walls to be intact; then the lichens are exerting a smothering
effect carried on through a saprophytic rather than a parasitic
action.

Lichen fungi sometimes become truly parasitic on their moss
hosts. This is especially true of Amphiloma, which is shown in
fig. 6. Here the lichen is an intracellular parasite. Amphiloma
haustoria soon break down the plastids, even in old moss tissues.
Amphiloma seldom attacks the meristematic tissues. Under
some conditions Physcia obscura may send hyphae of non-rhizoidal
nature into the meristematic moss tissues. Physcia also may so
incorporate moss into its thallus, that the epidermis of the lichen

324 BOTANICAL GAZETTE [NOVEMBER

develops on the lower side of the moss leaf and the rest of the
lichen on the other side, the moss becoming a veritable layer of the
lichen. In such cases the moss leaf is eventually destroyed.

The great opportunity for the parasitizing of mosses by lichens,
as they grow together in nature, cannot be over emphasized.
For the most part the lichens develop on the leaves of the moss.
Moss colonies in which apparently no lichens are present, when
sectioned or teased out almost invariably show tiny young lichens
developing in their leaves. Hundreds of lichens have been seen
developing from soredial masses, but very few from spores, hence it
is concluded that moss inhabiting lichens depend on soredia
rather than on spores for reproduction. BoNNtER’s observations
on the ability of lichens to germinate on, and eventually to kill moss
protonema, have already been mentioned. Since the protonemal
stage is a transient one, it probably does not take place in nature to
any great extent. The germination of lichens on moss leaves is
the rule, so far as cases where lichens eventually plaster themselves
over the mosses are concerned. The young lichen hyphae become
attached from their first formation. The environmental factors
control the future appearance of the colonies. From cultures and
field observations it is concluded that water is the dominating
factor of the control. Almost any moss colony, apparently free
from lichens, when grown in semimoist conditions, but occasionally
allowed to dry out, in a few weeks will produce young lichens visible
to the naked eye.

If these observations are borne in mind, it is easy to see why
so often the ideal lichen-moss-fern sequence is not carried out,
since the sequence is broken up by lichen stages in which the
lichens are more or less parasitic on the moss. If the rock surface
is rough enough, visible life may be initiated by moss, and a lichen
stage come in secondly. In any event a well established moss
stage may be crowded out by a more or less parasitic lichen mass,
which gives a secondary lichen stage succeeding the moss.

S
Lichens are able to destroy moss colonies. The destruction
is partly due to true parasitism and partly to smothering.

BOTANICAL GAZETTE, LXXI1 PLATE AMT

ft > whi
ys Ba” *
iy rae

McWHORTER on MOSSES AND LICHENS

1921] McW HORTER—MOSSES AND LICHENS CaaS

The development of lichens in moss colonies makes possible the
coming in of a lichen stage after the moss associations.

Great obligation is due to Professor W. J. G. LAND for sug-
gestions in regard to the technique used, and Dr. Gro. D. FULLER
for aid in the preparation of the manuscript and for reading the
proof.

eke OF Cae eae
Banos, P.I.

EXPLANATION OF PLATE XIII

The illustrations are all photomicrographs selected from a much larger

sian showing similar conditions.

1.—Cladonia pyxidata on moss, probably Dicranum; vertical section
iat colony showing moss plant with leaves cut to pieces and apical growth
stopped by action of lichen.

Fic. 2.—Cladonia pyxidata on an unrecognizable moss; organization of
moss leaves destroyed by action of lichen; lichen hyphae penetrated inter-
rind through moss tissues.

3.—Section of a moss-lichen mixture cut parallel to surface of colony,
saeivine lichen (Cladonia) hyphae penetrated into cells of apical region of moss
(Grimmia); hyphae indicated by arrow a could be traced through serial
sections to lichen mass just above; 6, moss leaf strongly attacked by hyphae.

Fic. 4.—Section from lower part of colony cut parallel to surface, ng
lichen sels tending to fuse with pectinized walls of moss tissues.

Fic. 5—Section through a Amphiloma-Grimmia mixture; Amphiloma
has organized on moss leaf; this lichen probably destroys more moss than
any other.

Fic. 6.—Portion of fig. 5 more highly magnified, showing: a, how lichen
may eotanletely destroy moss cells; 6. how hyphae dissolve pectinized layer of
cell walls of moss.

ANNUAL RINGS OF GROWTH IN CARBONIFEROUS WOOD
WINIFRED GOLDRING
(WITH PLATE XIV)

_ In a discussion of anatomical structure and climatic evolution,
JErFRey' emphasizes the absence of annual rings in Cordaitean
wood from the Carboniferous in latitudes south of England as
indicative of uniformity of climate, in contrast with the conditions
in the Triassic period, in which coniferous wood with annual rings
is found as far south as Arizona. His statement is as follows:

n the Paleozoic trunks which are supplied by the geological formations
of Southern Canada the organization of the wood shows great uniformity, and
there are no modifications of structure which indicate any periodicity in annual
conditions of growth. The truth of this statement is well illustrated by -

wood of a Cordaitean form from the Permo-Carboniferous of Hampton, Pines

frequently found in regions of higher latitude... . . The next illustration
shows the organization of a Carboniferous Cordaitean wood (Mesoxylon) from
the northern part of England, and consequently of considerably higher latitude
(54° N. in contrast to the 46° N., the latitute of Prince Edward Island). The
annual rings in the wood from the English Carboniferous are clearly marked.

For comparison with the situation revealed by the Cordaitean wood from
Northern England, a trunk from the Triassic of the southwest region of the
United States (Arizona) isshown ..... The annual rings are not so distinct
in the photomicrograph as they appear on the weathered end of the actual
petrified specimen. It will be clear from the information supplied in this case
that as far south as Arizona in the Triassic annual rings were more or less
clearly marked. A noteworthy variation in the annual temperature in that
somewhat remote epoch is thus indicated.2_ This situation presents an inter-
esting contrast to the climatic conditions which prevailed in the region of
Prince Edward Island toward the end of the Paleozoic. If the situation be
summarized, it is clear that in the later Paleozoic the difference between 46° N.
and 54° N. means the presence in the higher latitude of annual rings and their
absence in the lower one. On the other hand, in the beginning of the Mesozoic
(the Triassic), even at a distance of 10° south of the latitude of Prince Edward
Island, annual rings were quite clearly developed.

* JerFrey, E. C., The anatomy of woody plants. 1917.

? This might indicate variation in moisture instead of temperature.

— Gazette, vol. 72] [326

1921] GOLDRING—CARBONIFEROUS WOOD 327

Recently Berry has come into possession of part of a trunk of
Cordaites from Bartlesville, Oklahoma, which shows annual rings
of growth quite distinctly. The specimen comes from the Upper
Pennsylvanian (below the Americus formation). The location is
described as follows in a letter from the donor, Mr. GitBert Hart:

As near as I can judge, the trees are confined to a rather limited belt, and
are rather common there... . . The trees are found always below the Ameri-
cus. As yet I have seen none surely in place; the nearest to the original
position was in talus just below the first heavy limestone in the Admire forma-
tion. I feel sure that this is almost the true horizon.

The latitude of Bartlesville, Oklahoma, is 36°45’ N., about 10°
south of the Prince Edward Island locality, practically the latitude
of the Triassic forest of Arizona, where is found the coniferous wood
showing more or less clearly marked annualrings. If the occurrence
in Arizona argues for a “noteworthy variation in the annual
temperature’? in this area during the Triassic, then the annual
rings in the trees of the Oklahoma forest weve: indicate the same
for the end of the Carboniferous.

So far as known, the Oklahoma forest is the most southern
occurrence of Carboniferous wood with annual rings of growth
which has been noted; but such occurrences have previously been
noted in wood from the Carboniferous, or earlier, in latitudes as
far (or farther) south as Prince Edward Island. PENHALLOw,3
in his discussion of North American species of Dadoxylon, states
that, of the eighteen species now entitled to recognition, three
show more or less clearly defined growth rings, while in the remain-
ing fifteen they are obscure or obsolete. Of the species discussed
in this paper one, Cordaites pennsylvanicum (Dawson) Penhallow,
showing distinct growth rings, comes from the Carboniferous at
Pittsville, Pennsylvania (41°30’ N.). Two other species, C. Hamil-
tonense Penhallow and C. Clarkii Dawson from the Devonian
(Genesee shales) of Ontario County, New York (43°N.), show
obscure growth rings. In the second species, however, they are,
sometimes wanting. Both the Pennsylvanian and New York
localities are much farther south than the English (54° N.) or
Prince Edward Island (46° N.) areas.

3 Trans. Roy. Soc. Can. 6:57. 1900.

328 BOTANICAL GAZETTE [NOVEMBER

KNOWLTON,? in a survey of all the described species of Cordaties
and Dadoxylon, describes twenty-four species as showing growth
rings either distinctly or indistinctly. Of these, Cordaites ouangon-
dianum Dawson from the Middle Devonian of New Brunswick and
Dadoxylon (Cordaites) annulatum Dawson of the Middle Carbonif-
erous of Nova Scotia must be excluded because the original
descriptions were based on a complete misinterpretation of struc-
tural features (PENHALLOW, p. 56). Of the other species, nine are
from the Carboniferous, the remainder from the Permian. Of the
Carboniferous species, seven are from latitudes south of England,
and of these four species are from latitudes as far, or practically
as far south as Prince Edward Island, as follows: Nova Scotia
(46° N.), three species; Niederburbach in Upper Alsace (47°45’ N.),
one species showing distinct rings of growth. Most of the Permian
species range in latitudes from 50°15’ N. to 51° N., but one species, —
with distinct growth rings, is recorded from Val d’ Ajol, Department
of Upper Saone, France (47°40’ N.).

These data show that the extreme southern extension of a
variable annual temperature in the Triassic period is not particu-
larly remarkable. As far back as the Middle Devonian (Genesee) —
there must have been noticeable variations in climate in fairly
low latitudes, in order to effect even the slight variations in wood
formation noted, while in the Carboniferous the development of
distinctly marked annual rings of growth indicates a pronounced
seasonal variation in the climate of that period, even in far southern
latitudes. This is also shown, but less markedly, in the Permian.

The specimen from the Upper Carboniferous of Bartlesville,
Oklahoma, represents part of a trunk of a tree of considerable size,
for in the section of trunk preserved, a radius of 5.5 inches of wood
is shown with neither pith on one side nor cortex on the other.
PENHALLOW gave the name Cordaites recentium to an undescribed
species from the Permian or Permo-Carboniferous of Prince Edward
Island, which Sir Witt1AM Dawson had regarded as related, if not
identical with C. materiariwm Dawson from the Upper Carbonit-
erous of Nova Scotia, Newfoundland, Illinois, etc. The species
was not figured, but after a comparison of PENHALLOW’s description

4Proc. U.S. Nat. Museum. 12:601-617. 1890.

1921] GOLDRING—CARBONIFEROUS WOOD 320

with thin sections of the Oklahoma trunk, there seems no real justi-
fication for a separation of the latter from the Prince Edward
Island species, in spite of the great distance between the two
localities. The original description follows:

Cordaites recentium (Dawson) Penhallow
Transverse.-—Tracheids 47 X53 mw broad, the walls much reduced by decay.
Radial.—Ray cells all of one kind, about equal to two tracheids; the

lateral walls with round pits about one ( ?) per tracheid; the cells conspicuously
narrower at the ends.

Bordered pits in a single row, compact, large, compressed and transversely
oval or oblong, 15.622, the orifice very variable, from oblong to round,
often eccentric, but typically round and central. When distant the pits are
round and smaller.

- Tangential —Rays medium, 1-2 seriate, the very broad cells 41 w, thin-
walled, round and squarish.

PENHALLOW makes no mention of the occurrence of annual
rings of growth, which are very distinctly shown in the Oklahoma
specimen. The rings of growth shown in the transverse section
are variable in width; one has a width of 3 mm., a second 8 mm.,
and 6mm. of a third are shown. The growth rings show very
well on the weathered surface of the trunk; in one place the growth
rings have the following apices ena 3mm., 3.5mm., 7.5
mm., 3.5mm., 3 mm., 3.5 mm., ete; im iuoehies hice,
4mm., 4mm., 4mm., etc. On re Shee therefore, the growth
rings are of about even width.

The bordered pits in a single row on the radial walls of the
tracheids distinguish C. recentium from C. materiarium, in which
the pits are numerous throughout the tracheids, chiefly in two,
sometimes in three or four rows. The ray cells are narrowed at
the ends, but not conspicuously so, and are equal to 2-6 tracheids
in the Oklahoma specimen, as in C. materiarium, the longer cells
being more frequent. The pits on the lateral walls are round, and
so far as can be ascertained, one to a tracheid as described by
PENHALLOW. The rays are numerous and in general very long,
composed of from two to at least forty-seven cells superimposed
upon each other and tapering toward each end. The rays are
described as “‘1~2 seriate,’”’ but usually they are uniseriate. In no

330 BOTANICAL GAZETTE [NOVEMBER

place have they been found biseriate throughout. The biseriality
is usually confined to the middle of the ray, although it may also
occur at one or both ends; often it is confined only to the depth of
one to three cells.

C. recentium resembles Dadoxylon antigquum Dawson (Upper
Carboniferous of Nova Scotia) in the possession of bordered pits
in one row, but differs from it, among other things, in the possession
of practically uniseriate rays, whereas D. antiquum has multiseriate
rays two to four cells wide. D. prosseri Penhallow (Permian,
Chase County, Kansas) has numerous uniseriate rays (biseriate
in part), but the bordered pits are smaller, and although they may
occur in one row on the tracheid walls, are chiefly in two rows.

Photographic reproductions of transverse, radial, and tangential
sections of the wood of this species are shown in the accompanying
plate.

Jouns Hopkins UNIVERSITY
Battimore, Mp.

EXPLANATION OF PLATE XIV
Fic. 1.—Transverse section, <3.
Fic. 2.—Transverse section, X 50.
Fic. 3.—Tangential section, X 50.
Fic. 4.—Radial section, X 50.

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BOTANICAL GAZETTE,

CURRENT LITERATURE

BOOK REVIEWS

Cytology

A book on cytology from the botanical standpoint has long been needed,
and consequently botanists will welcome the vigorous, suggestive presenta-
tion of the subject by SHarp.t| The zoological side is also presented, so that
everywhere the differences and similarities in plant and animal cells are kept
before the reader.

This is the first time that such a comprehensive treatment of the whole
subject of cytology has been attempted by a botanist. The chapter headings,
nae indicate the scope of the work, are as follows: Historical sketch; Pre-

minary description of the cell; Protoplasm; The nucleus; The centrosome and
een Plastids and clicmleacaies: Metaplasm, polarity; Somatic
mitosis and chromosome individuality; The achromatic figure, cytokinesis, and

organs in sescaye Mendelism and mutation; Sex; age; Weissmanism
and other theories. Any discussion or comment on details would require such
an undue amount of space, that reference will only be made to the book itself.

The illustrations are numerous and exceptionally well drawn. Accompa-
nying the descriptions of vegetative mitosis, reduction of chromosomes, and
the réle of the nucleus in heredi ty are numerous diagrams which will be appreci-
ated both by students and investigators. The large number of new figures
and diagrams is refreshing, and, as one turns the pages, he sees at a glance
that the book owes little to shears and paste. Each subject is followed by a
very full bibliography arranged alphabetically. The citations are unusually
complete. The index is also commendable, with reference to res in full
faced type and with words which might be unfamiliar to some botanists or
zoologists followed by an explanatory word in parenthesis, as Eloesis (palm),
Ectocar pus (brown alga), Enchenopa (bug), etc.

SHARP’s own contributions in the field of cytology, his skill as a practical
technician and artist, as well as his experience in teaching the subject have
fitted him for the production of this book, which will be indispensable to
botanists, and should be of great value to those zoologists who feel the need
of an authoritative presentation of the botanical side of cytology.—
C. J. CHAMBERLAIN

*SHarp, L. W., An introduction to cytology. 8vo. pp. xiiit452. New York:
McGraw Hill Book Co. 1921. $4.

33t

332 BOTANICAL GAZETTE [NOVEMBER

In Lower Florida wilds

A volume by Srmpson,? described as a naturalist’s observations on the
eology, geography, and life of the more tropical part of the state, presents
much scientific information in an attractive popular manner, well illustrated
with plates from good photographs. Two chapters should be of particular
interest to plant ecologists, since the one outlines the plant succession from the
pine lands to the ‘‘hammocks,”’ while the other gives a picture of the primeval
forest of semitropical type. The author’s opinion that the broad level ever-
green forest of the “hammock” is the true climax vegetation seems well
founded, while his emphasis upon the destructive and retrogressive effect of
fire appears to furnish a part, at least, of the explanation why such vegetation
has not dominated a larger portion of the peninsula.
The tale of the evolution of the land is attractively told, and seems as
scientifically accurate as the story of the succession in the forests.—
Geo. D. FULLER.

NOTES FOR spears

tganic acids and anthocyanin formation.—ComBEs,3 Rose, 4 NICOLAS,$
and other workers have found that hives de formation is accompanied
by increased oxygen fixation. M : EBLE? and ARMSTRONG, and

containin,
that of Compes,? WirtstATrer,” and Everest," has shown that anthocyanins

2 Simpson, C. T., In Lower Florida wilds. 8vo. pp. xv+404. pls. 64. maps. 2.
New York: Putnam’s Sons. 1920. $3.50

3 CoMBES, R.. Les echane Aj ye, )

t la formation et la destruc-
tion des pigments anthocyaniques. Rev. Gen. ee 273177-212. IgI0.

4 Rose, E., Etude des echanges gazeux et de la variation des sucres et des gluco-
sides au cours de la formation des pigments gap wage ses dans les fleurs de Cobaea
scandens. Rev. Gen, Botanique 26:257-270. 19

5 Nicotas, G., Contribution a l’étude des ssi, qui existent, dans les feuilles,
entre la respiration et la presenxe del’anthocyane. Rev. Gen. Botanique 31:161-178.

I9gr

, M., Sur lorigine de l’anthocyanine, deduite . _ de
tiene adie. parasites des feuilles. Compt. Rend. Acad. Sci 300. 1907-
7 Keesie, F., and Armstrone, E. F., The rdle of oxidases i in o ae of
anthocyan pigments of plants. Jour. Genetics 2:277-311. 19
Mizcg, E., eroruaay sur les principales espéces de panel Thesis for
Doctorate. Paris. 19

9 ComBES, R., Pieslecl tion experimentale d’une pose identique a celle qui
se forme tas les euilles rouges en seat en partant S un compose extrait des
— bonderye ORE Rend. Acad. Sci :1002-1

004
, Uber die rer He Bluten ond eT Sitz. Ber. Akad.

Wiss. baci al oe
™ EVEREST, E., Th duction of anth ins and antho idi Proc. Roy.
Soc. B. 87: pa 1914.

1921] CURRENT LITERATURE 333

can be produced from flavones by reduction. In the light of this work, Miss
‘OHLER™ was led to believe, as Nicotas and others previously ha n,
that anthocyanin formation should be correlated with organic acid accumula-
tion, her contention being that organic substances such as carbohydrates were
oxidized to organic acids, thereby reducing certain flavones and causing antho-
cyanin formation.
he evidence for the accumulation of organic acids during formation of
red plant pigment has been more or less contradictory. WHIESNER®™ and
Kraus” have found that acidity of the cell sap increases during autumnal red-
dening of leaves. Astruc’ has shown that acidity descreases in petals of
flowers during the reddening process. The tissues immediately beneath the
red epidermis of apples were found to be less acid than tissues beneath a green
epidermis in the same fruit, as determined by RrvreRE and BAILHAcHE.*®
BERTHELOT and ANDRE” state that the amount of free acid in the plant as
determined by titration of expressed juice bears no relation to the total amount
of organic acid in the plant, as for the most part the acids are combined as
salts of plant bases. Miss Kouter also objects to titration of expressed juice
because of the tendency of the alkali used to combine with phenolic compounds
such as tannins and anthocyanins. After several unsatisfactory attempts to
precipitate the phenolic compounds by the use of hide powder, zinc acetate, and
analgesine (antipyrine), Miss Kouter found that free organic acids could be
quantitatively dialyzed out of the expressed juice and therefore used this
ethod in her work. The acids were then titrated with a base and calculated
as free organic acid. Combined organic acids were determined, using oven
dried samples of tissue, by heating at dull red heat in a muffle. A known
quantity of N/r1o sulphuric acid was then added to the ash to neutralize the
bases liberated by the combustion, and the acid residue titrated with alkali to
d how much acid was neutralized by the ash. € e obtained in this
way was added to that of the free organic acid and the sum placed under the
caption “total organic acids.” Total organic acids determined in this way
were found to increase in corollas of Cobaea scandens during the process of
development from bud to mature flower, along with anthocyanin development,

” KonLer, DENISE, Etude de la variation des acides organiques an cours de la
pigmentations anthocyanique. Memoir to Faculty of Science, Univ. Paris. 1921.
SNER, J., Untersuchungen iiber die Herbstliche Entlaugung der Holzge-
wachse. "Sis. Ber. Akad. Wiss. 64:465-510. 1871.
™ Kraus, C., Studien iiber die Herbstfarbung der Blatter und iiber Bildungweise
der Pflanzensauren. Buchner’s Repert. Pharm. 22: 273. 1873.
*s Astruc, A., Recherches sur l’acidity végétale. Ann. Sci. Nat. Bot. 17:65-109.
Tg03.
© Riviere, G., and BarHacue, G., De Vinfluence de la lumiere directe sur la
composition pie des fruits. Jour. ‘Soe. Nat. Hort. France, IV. 9:627. 1908.
7 BERTHE M., and AnpbrgE, G., hate sur la gaat des acides chez
les vegetaux. Compt. Rend. Acad. Sci. 327502.

334 BOTANICAL GAZETTE [NOVEMBER

when the flowers were allowed to remain attached to the plant. When detached
there was no increase during the opening of the corolla. Leaves of Ampelopsis
tricuspidata gathered September 17, October 1, and again on November 2,
showed a progressive increase in total organic acids during the autumnal redden-
ing. When allowed to redden detached from the plant, there was no accumula-
tion of acids. Small plants of buckwheat, when germinated in the dark, showed
a steady increase in total acids until the eighteenth day after germination.
When exposed to light during this time, a red pigment developed in the hypo-
cotyl axis, but no corresponding increase in total acids was found, either in
plants attached to or detached from the parent stock. Miss KOHLER states
that this fact may mean that the destruction of organic acids formed in this
case is greater than their production.

It is to be regretted that Miss KoHLER has not included some similar deter-
minations upon leaves which remain green under certain conditions and which
redden under certain other conditions, in order that a comparison might be
made. There is some doubt in ine reviewer’s mind that titration of ash, after
incineration of plant tissue, gives an approximate value of the combined organic
acids in the tissue before pce. Plant tissue is a complex material.
Salt combinations other than those of organic acids with inorganic bases may
be altered greatly by incineration, and may leave a basic ash. Organic acids
may as well be combined with organic bases within the plant and both would
be lost on heating. There is even the possibility of a mixture of inorganic
salts becoming more basic upon heating in a muffle. There is a tendency
toward accumulation of mineral salts as the leaf ages during autumn, accord-
ing to Partapin."® This accumulation might account for an increase in
basicity of ash independent of color formation. In the same way migration
of mineral salts into corollas and subsequent use of certain anions such as
sulphates, nitrates, and phosphates in building complex compounds connected
with reproduction may leave basic elements which combine in various ways
and which would increase basicity of ash upon incineration. On account of the
many criticisms which might be justly directed against this method of determi-
nation of combined organic acid, and on account of the insufficiency of our
knowledge of complex plant compounds, it is hoped that the author of the
paper will continue her studies, including some corollas which do not redden
at the time of opening, and some leaves which do not redden in autumn,
together with goa methods for quantitatively determining the acids in
question.—J. M. Arruur.

Vegetation of Lower California.—<As the result of an expedition conducted
by members of the United States Bureau of Biological Survey in 1905 and 1906,

* PALLADIN, V. I., Plant physiology. p. 83. 6th. ed. transl. by LivINGSsTON,
B. E., 1917.

1921] CURRENT LITERATURE 335

NELSON” has given us a rather extensive account of the geography and resources
of one of the least known regions of the continent. The larger portion of the
report is occupied with an account of the exploration of the peninsula from
north to south. Although 800 miles in length and from 30 to 100 miles in
width, it possesses a population of little over 30,000, more than half of which
is found in the extreme north on the delta plain of the Colorado River. Much
of this sparcity of population is due to the essentially desert character of the
peninsula as a whole. Rainfall records are very scanty, but show that there
is rarely over ro inches of annual AS cp pies while over large areas from one
to five years may pass with practically no . Some idea of the general
aridity may be formed from the fact that pecshcal three-fourths of the entire
length of the peninsula there are no forests whatever, only the tops of the
higher mountains at the northern and southern ends being covered with trees.
The only extensive forests are those contained in the northern area, where trees
extend along a narrow belt 150 miles long on the higher slopes of the Juarez
and San Pedro Martis Mountains, and within this area the merchantable
timber does not cover more than 400 square miles. re the more important
species are Pinus Jeffreyi, P. contorta, P. Lombesbtans. Abies concolor, and
Librocedrus decurrens. Associated with them are other trees and shrubs, the
Same or similar species to those of southwestern California, often constituting
a scattered chaparra

The essentially desert character of the remainder of the peninsula is also
shown by the inclusion of three-fourths of the entire land area within the Arid
Lower Sonoran Life Zone and of more than half of the remainder within the
Arid Tropical Zone. This zonal division also corresponds closely to the three
main elements of the flora derived respectively from (1) the mountains and
foothills of southern California, seen in the northern forests and scrub; (2) the
deserts of the northwestern Sonora and southwestern United States; and
(3) the lowlands and mountains of the southern Sonora on the mainland of
Mexico

Cacti appear to reach a climax in the Lower Sonoran, both in size and
abundance. In his annotated list of species GOLDMAN” gives over 30 species

longing to 11 genera, varying in size from the smallest to such large forms

as Lemaireocereus eruca, with huge, prostrate, caterpillar-like stems 6 or 8 ft,
long, and the largest of the giants, Pachycereus Pringlei, more than 50 ft. high
and three ft. in diameter. Many of the associated plants are wv same as as those
of California, including species of the Yucca, Agave, Fouqueria, Cercidium,
Parkinsonia, Prick, Covillea, and palms of the genera Washingt onia and

NELSON, E. ye atte California and its natural resources. Mem. Nat. Acad.
Sci. 16: ghee pls. 1 2

Eos os pee records of an expedition to Lower California. Contrib.
US. Pose ‘Het. 16:309-371. pls. 103-133. Map. 1916.

336 BOTANICAL GAZETTE [NOVEMBER

Erythea, these last at the base of the mountains. In the southern third of the
peninsula many distinctly tropical genera appear, such as Ficus, Mimosa,
Cassia, Albizzia, Jatropha, Haematoxylon, Lantana, Manihot, and Chiococca.

ong the more remarkable endemic desert forms, two trees may be
mentioned. One, alontteie to the Anacardiaceae, Pachycormus discolor, is
found in the extremely arid central séction of the peninsula. Seldom ro ft. in
height, the branches often shoot out twice that distance from the trunk, while
their thickness (1 ft. or more), their abrupt ending in a few short twigs covered
with red flowers, “reminding one of the proboscis of an elephant holding a
nosegay,” give a remarkably grotesque appearance to the tree. The leaves
are minute and fall off before the flowers are fully developed. The associated
monotypic genus [dria columnaris is in the Fouqueriaceae, and appears as a
tree reaching 50 ft. in height in a scattered open forest. In contrast with the
preceding it bas a straight columnar trunk, usually without large branches.
Illustrations of these and many other interesting and unusual plants add
much to the interest of both reports—Gro. D. FULLER.

Rubus in New England.—Brarnerp and PEITERSEN,” recognizing that
“Rubus is one of the most polymorphic genera in the entire plant kingdom,’
have presented the blackberry group of that genus as displayed in New Eng-
lan e authors say that the remarkable variation in the number of species
Noa in oe various taxonomic works is due to too great reliance upon

cimens, to failure to appreciate the variations due to environ-
corial Sonica and to lack of appreciation of the extent of interbreeding.
The present study is based upon data from material in the field, behavior in
garden cultures and controlled plots, characters of the progeny of supposed
natural hybrids, and behavior of progeny when artificially crossed. The
result is that the authors recognize twelve valid species of New England black-
berries, and a long list of hybrids:

In following up the experimental work, PErrersEN*? has reached the
following conclusions: variations ‘due to external factors are very marked;
primordia of the prickle, glandular hair, and simple hair are present in all
species; a large percentage of infertility occurs in most species, largely due to
defective pollen; cross pollination is the rule in all species, all the species
studied being either nearly or completely self-sterile; all the species are capable
of inter-crossing under favorable conditions; duplicates of natural hybrids
were produced en the progeny of a mucha of so-called species segre-
gated as hybri
The paper is a good illustration of the test of genetics applied to taxonomy.
at.

* BRAI INERD, Ezra, and Perrersen, A. K., Hgesoegian of New bcoz their
classification. Bull. 217, Vermont Agric. Exper. Sta. pp. 84. pls. 36.

7 PEITERSEN, A. K., Blackberries of New cena sent status oe the plants.
Bull. 218, © aout t Agric. Exper. Sta. pp. 34. pls. 19.

VOLUME LXXII NUMBER 6

THE
DOTANICAL GeAZETTE

DECEMBER 10921

OPTIMUM TEMPERATURES FOR FLOWER SEED
GERMINATION:
GEo. T. HARRINGTON
(WITH TEN FIGURES)

The proper conditions for the germination of flower seeds is
a subject upon which but little work has been published. During
the spring of 1912, preliminary work was done in the seed labo-
ratory of the United States Department of Agriculture on the
temperature conditions best suited for the germination of a few
of the more common flower seeds. During the winter and spring of
1913-1914, further work was done with the same species investi-
gated in 1912, and with a few additional species. The publication
of the results has been unavoidably delayed for several years.
In the meantime, the recommendations included herein have been
followed by the seed laboratory with good results.

The seeds included in the investigation were those of Impatiens
balsamina, Eschscholizia californica, Iberis amara, Cosmos bipinnatus,
Kochia scoparia, Delphinium ajacis, Calendula officinalis, Reseda
odorata, Tropaeolum majus and T. minus, Viola tricolor, Petunia
hybrida, Dianthus chinensis, Papaver spp., Portulaca splendens,
Antirrhinum majus, Lathyrus odoratus, and Zinnia elegans. Only
a small number of samples of some kinds was included in the actual
investigation. The subsequent experience of the seed laboratory,
however, includes the germination of such kinds of seeds both at

- fhe co of work done while in the Seed Laboratory, United States Department
of Agricul
337

338 BOTANICAL GAZETTE [DECEMBER

the temperatures recommended and at other temperatures, and
has verified these conclusions. Duplicates of one hundred seeds
each were used in making nearly every germination test. In a
few tests duplicates of only fifty or seventy-five seeds each were
available, on account of the small size of the samples used.

Method and apparatus

The sweet pea and nasturtium seeds were tested in moist
canton flannel, using two thicknesses of the flannel under the
seeds and two thicknesses over them. Balsam, California poppy,
cosmos, larkspur, marigold, mignonette, pansy, and zinnia seeds
were tested between moist blotting papers, two thicknesses above
and two below. Candytuft, cypress, petunia, pink, poppy, portu-
laca, and snapdragon seeds were tested on top of four thicknesses
of moist blotting paper. In the tests which were made in 1914 the
poppy seeds were tested both between moist blotting papers- and
on top of moist blotting paper.

All tests were made in standard water-jacketed copper germinat-
ing chambers, and were continued until no more seeds or only an
occasional one germinated. The progress of germination was care-
fully watched, and all germinated seeds were counted and thrown
away at frequent intervals in the tests which were made in 1912,
and each day after germination began in the tests which were
made in 1914.

The seeds were tested with the use of the constant temperatures
15°, 17.5°, 20°, 22.5°, 25°, 28°, and 30°C, and with daily alterna-
tions of temperature between 20° C. as the lower temperature and
28°, 30°, 31°, 32°, 35°, and 37° as the higher temperatures in the
different alternations. The temperatures hamed as the higher tem-
peratures in the alternations are those indicated by thermometers
inserted in the tops of the chambers, and are 1° or 2°C. higher than
the highest temperatures reached within the blotters or cloths in
which the seeds were being tested. The alternations include some
in which the seeds were kept from four to seven hours daily in a
chamber which was constantly maintained at the higher tempera-
tures, and the rest of the day in another chamber at the lower
temperature; and others in which only one chamber was used,

1921] HARRINGTON—GERMIN ATION 330

this chamber being slowly heated during the forenoon, and cooled
either slowly or rapidly as desired during the afternoon. When
only one chamber was used the heating was accomplished by means
of a properly adjusted gas flame below the chamber, and the
cooling by means of a graduated stream of cold water in the top
of the water jacket.

The species investigated may be divided into two groups: (1)
those whose seeds germinate well at any constant temperature from
17.5° to 22.5°C., and also with temperature alternations; (2) those
whose seeds require a temperature cooler than 20° C. for complete
germination. Some of the samples in each group contained many
dead seeds, or seeds incapable of germination at any temperature.

Results

Although a direct comparison between the tests made during
the two periods (1912 and 1914) is impossible, the results of all
the tests can best be discussed together. They will be considered
from three standpoints: (1) the effect of alternating versus con-
stant temperatures; (2) the effect of the different temperatures
upon the germinating capacity; and (3) the effect of the different
temperatures upon the rapidity of germination.

ALTERNATING VERSUS CONSTANT TEMPERATURES

All the species included in the investigation, with the possible
exception of petunia, germinated as completely and as quickly with
a favorable constant temperature as with any alternation of tem-
peratures. It should be remembered, however, that taking the
seeds out of the chambers to count those germinated introduced
a brief change of temperature which may not have been entirely
without effect. The influence of this brief temperature change, if
it has any, would be greater when the germinated seeds are counted
every day or two as in these experiments, than if they were counted
less frequently.?

? While the use of an alternation of temperatures does not seem to be necessary
for satisfactory germination of the kinds of seeds treated in this paper, it is very
desirable, and in some cases imperatively demanded, with many other kinds of seeds.
This subject will be treated in an article to appear shortly in the Journal of Agricul-
tural Research,

340 BOTANICAL GAZETTE [DECEMBER

It may be convenient in seed testing laboratories to use alternat-
ing temperatures in conducting germination tests of some of the
kinds of seeds considered, in order to conform to methods estab-
lished for use in testing the germination of other kinds of seeds.
This matter will be discussed later.

GERMINATING CAPACITY

Twelve of the species studied belong in group 1. Table I
shows the results, so far as total germination is concerned, of the

TABLE I
GERMINATION OF FLOWER SEEDS OF GROUP I
AVERAGE PERCENTAGES OF GERMINATION
First series of tests* Second series of tests*
SEEDS fe
oo .
N °. se ° ° N 17:5
oe 20°30" as et Kes 37° 28° 1 30° ot rer pee 5° 25° | 30°
lots =e lots 20°-30°

Balsam......... t | 98 to.g9 | 98 | 98 | 08 3 | 94 | 94 to 98 | 97 | 98
Cal. poppy...... 2 | 62 to 70 | 62} 62| 59 |....] 1 | 72 | 77 to 85 | 74 | 68
Candytuft...... 2 | 74to 80 | 83 | 70 | 74 | 62 | 5 | 79 | 78 to 80 | 78 | 76

Cosmos of 1 BO10 88 10...) BOs ivi e.t (2 1 7 to 92
ce 1 | ot to 98 | 88 | 88 | 84 2 | 76 | 78 to 80 | 74 | 78
Marigold....... THONGS te RAR A 8 vowed, cuit eo BOO OF to ag | O21 oP
Mignonette. .. . . 2 | 68to 71 | 72 | 66 | 62 3 | 73 | 66 to 71 | 65 | OF
Petunia...,.:.... 2 | 67 to.74 | 64 1 56:1 70 |... 2| 76 | 71 to 76 | 79 | 80
oe rs ces t | 90 to 96 | 90 | 92 | go j....| 7 | 89 | 88 to ox | 87 | 87
Portuistac (5273: I | 86 to 94 | 83 | 90 | 86 | 87 | 1x | 71 | 74 to 80 | 75 | 7
Sweet pea....... aS GS OG seiabidcchacrlecs de 9 DBE | R410 OE Pe
i SE I | 90 to 94 | 96 | or | oF 2| 79 | 79 to 85 | 78 | 74

* The two series of tests were entirely distinct, no lot of seed d in both series.

experiments with this group. Each of the twelve species germi-
nated about equally well at any constant temperatures from 75°
to 22.5°C., and with the temperature alternations 20°-28°, 20°-30°,
20°-31°, and 20°—32° C,

Seeds of balsam, candytuft, cypress, marigold, mignonette,
petunia, pink, sweet pea, and zinnia germinated as completely at
15°C. as at warmer temperatures. Seeds of balsam, candytutt,
cosmos, cypress, petunia, pink, portulaca, sweet pea, and zinnia
germinated as completely at some or all of the constant tempera-

1921] HARRINGTON—GERMINATION 341

tures warmer than 22.5°C. as at cooler temperatures. Four of
these, candytuft, pink, portulaca, and zinnia, germinated somewhat
less completely at 30° than at 25° or 28°C. Seeds of balsam,
California poppy, candytuft, cosmos, cypress, mignonette, pink,
portulaca, sweet pea, and zinnia germinated as completely with
one or both of the warm temperature alternations, 20°—35° an
20°-37° C., as with cooler temperatures.

TABLE II
GERMINATION, OF SEEDS AT DIFFERENT TEMPERATURES
AVERAGE PERCENTAGES OF GERMINATION
‘Thnrenaviie LARKSPUR Basho * Pansy Poppy SNAPDRAGON
2 4 Ig12 19I4
(rot) | (3 lots) | (2 lots) | (rlot) | (Tot) | (3 lots) | (8 lots) | (rlot) | (s lots)
eC 53 BO ly Sos a errs ae 2 te 3
ie Cc A RUS Caneel: 81 eee ae a ee RE {ey Damages 66
TFS ones cece e ne 67 63 ode Waban 87 oF po ie ee 67
ee On oe 48 28 74 46 78 70 60 48 62
Doe oe OO Ses LS ESS Peay CR Re 59
20-28" Uo faa, BA Aeiec ache cee. ee ae ae HO isa as 440 [2 as
caidas WU acre nore ce Faded Wem g(t Bis He 48 ess ON ec. RA Loy
(cooled rapidly)
) °
BO BL veces ec ene BO ec oe ee ves ee ds ees
2030 ose enee es 25 8 65 56 74 66 52 46 52
BO 32 vere vee e ee vs ee es Role: AS |eveses det Eee ee Pee
SO TSO Ue ee haw nls eee lines ees 4B lives Pee EES Gar) ae a ares
(cooled slowly)
BOTST tv ene ve ues Been POMC, U8 Saas Fe AA uc Gs OE ee ie
Phos ss o'4 5 ok Ee gabe Be gen COO OR le, ele ieee ie
gh Os Ses erase bo SE > Oe Sar oo he. Cae ena
BO ake Cuca es dee Paha Cie Geer Pi ed ee We Bere 19

Seeds of larkspur, nasturtium (2 species, 1 sample each), pansy,
poppy (a number of species), and snapdragon belong to group 2,
which germinated most completely at a temperature cooler than
20°C. In 1914 the larkspur, poppy, and snapdragon seeds were
tested in an icebox in which the average temperature was about
8° C., as well as with the temperature conditions used with the
other kinds of seed.

Table II shows the average percentages of germination of seeds
of group 2 under the different temperature conditions, arranged
in the order of increasing average temperature of the germination

342 BOTANICAL GAZETTE [DECEMBER

blotters, regardless of the highest temperature reached in the
different alternations.

Pansy seeds germinated more completely at 17.5° than at
15°C.; larkspur and poppy more completely at 15° than at
17.5°; while with nasturtium and snapdragon seeds there was no
difference between these two temperatures. Although the lark-
spur seeds tested in 1914 germinated even more completely in the
icebox than at 15°C., the slowness of germination in the icebox
makes the use of so low a temperature undesirable. Furthermore,
the difference in total germination in favor of the icebox tempera-
ture was only with one lot of seeds, the other two germinating
practically the same as at 15°C.

The rather poor samples of pansy and snapdragon seeds which
were tested in 1912 germinated more completely with an alterna-
tion of temperatures than with a constant temperature of 20°C.
These samples were not tested with the cooler constant temperatures
which proved most favorable in 1914. The decrease in the average
percentage of germination with rise in temperature above the opti-
mum was rapid in the case of larkspur, somewhat slower in the
poppy, and slow and gradual in nasturtium, pansy, and snapdragon.
The low optimum temperature for germination of larkspur and
poppy is reflected in the recognized practice of sowing these seeds
in the fall or véry early in the spring, when the ground is cold.
It is significant, too, as showing the adaptation of the seed to the
general physiology and life history of the plant, that poppies fail to
make satisfactory growth if started after the advent of warm weather
when the soil temperature is above the optimum for germination
of poppy seeds. In the case of larkspur and poppy, there was a
great deal of variation in the relation of temperature to complete-
ness of germination between even the different lots of the same
kind of seeds. These two species will be considered separately in
the following pages.

TEMPERATURE REQUIREMENTS FOR GERMINATION OF LARKSPUR
SEED.—Fig. 1 shows graphically the contrast in response to differ-
ent temperatures of two different lots of larkspur seeds, tested
simultaneously in 1914. Each of the three lots tested in 1914
germinated much more completely in the icebox than at 17.5° C.
Fig. 2 shows the total percentages of germination of one lot of

1921]

HARRINGTON—GERMINATION 343
larkspur seeds with the different temperature conditions used in
1912. The different alternations are arranged from left to right

| TEVIPER ATURE «,
°
9 G
WX . . ‘ oP 4
AN) : Y AN Vj
G 5 LN S
oie x DS \ % \
90
80 Y =
Saen
~~
DD
Aa!
\ “
i \

FES CEM.
Q

2.)
AS)
raze
la
—

Pn}

Fic. 1.—Germination of two lots of larkspur seeds

in the order of increasing mean temperature in the blotters. The
percentage of germination decreased regularly as the temperature

344 BOTANICAL GAZETTE [DECEMBER

at which the germination test was made increased from 17.5° to
28°C. The percentage of germination was 14 per cent less in the
icebox than at 17.5°C., but greater than at any temperature
warmer than 17.5°C. No record was kept of the temperature

: <
40

Fic. 2.—Germination of one lot of larkspur seeds

in the icebox, but it was probably cooler than in 1914, when each
of the three samples tested showed a higher percentage of germina-
tion in the icebox than at 17.5° C.

TEMPERATURE REQUIREMENTS FOR GERMINATION OF POPPY
SEED.—One lot of poppy seeds used in the investigations in 1912
was of the opium poppy, Papaver somniferum, the other two lots

° oy Lie % 5 % % 9

Wg < 9 nN re Ke r g %
RN . q )

Po \ v % u v Ny xR q q

1921] HARRINGTON—GERMINATION 345

were not determined as to species. In 1914 three lots of seeds
of Papaver somniferum, three lots of the horticultural variety
“Shirley” of Papaver rhoeas, and two lots of an undetermined
species were used. ‘Table III gives the percentages of germination
of the eight lots which were tested in 1914. In general, the seeds
of Papaver somniferum were much less sensitive to temperature
conditions than were the seeds of the other species. Fig. 3, con-
structed from the averages in table III, illustrates the relation of
temperature to completeness of germination of the three species
of Papaver included in the tests of 1914. Fig. 4 shows the differ-

TABLE III

GERMINATION OF DIFFERENT SPECIES OF POPPY AT DIFFERENT TEMPERATURES

GERMINATION

TEMPERATURE Papaver somniferum |Papaver rhoeas var. “‘Shirley”| . Papaver sp.

No. | No. | No. | Aver-| No. | No. | No. | Aver-} No. | No. | Aver-

5440 |250482/250768| ages |250224/250693/250752| ages |250196/250197| ages

Icebox eee ae SS.l 98) Bek ya ti eet 96 61 9o1 861 88) 9a
BS Met en even wa 7019904: 041 -O8 ESO) SB) St) 96:1) Oe): 90] 96
ih er O51 96) G8}. 99) seb 98]. Srl 72) ot | oot 9
20°... git tesese OO b° 78: FB TT BE Se) 80-1 40 69
iat a a 52476] Gg). <Gh). 36) 40 at]; 27 1 Say Se
vig Meee ee S81 98) 64) -67 |: eB Tt 391 36) 287 og] 841. 54
eae es 10°]. 26 6 14 I ° 2 I ° I I

ences in germination of three lots of seed of Papaver somniferum with
different temperatures. The temperature alternation 20°-30° C.
Tepresents a mean temperature in the blotters of practically
22.5°C. The equivalent value of these two temperature conditions
for the germination of larkspur and poppy seeds is evident from
the results.

GERMINATION OF POPPY SEED BETWEEN BLOTTERS AND ON TOP
OF BLOTTERS.—As previously stated, poppy seeds were tested in
1914 both on top of and between double thicknesses of moist blotting
paper. In the icebox the average percentage of germination on top
of blotters was sixty-seven, between blotters seventy-three. At
15°C. the average percentages were respectively eighty and
Seventy-five. In the tests with each of the other temperature

346 BOTANICAL GAZETTE [DECEMBER
conditions, the average percentages of germination on top of
blotters and between blotters differed from each other by less

TELSITPER ATURE ts
.)
Soak 8 ee
wy =f N S r n S
A LN} 5
ok, ° = vy \ N "
wu

PLP Riso
S
0
id
Ell eee
a7. POS e
co?
waged 7°

—

Fic. 3.—Germination of three species of Papaver

than 2 per cent. Averaging the results of the fifty-six tests (seven
tests of each of eight lots of seeds) on top of blotters, and fifty-six

1921] HARRINGTON—GERMINATION

347

between blotters, gives fifty-five as the average percentage of
germination in each case. There is, then, no advantage in either

TEVIPERA TURE &
°
ey ee
We BW ee 8
voo8® 8 ~ % % % %
ER, <5.
S02 ye tig
ies a
age
Get
80 NUMBER SORE 2 By DOUELE
——————— cay
_ es
70 \&

@ oO 7 a
My aoe

Fic. 4.—Germination of three lots of Papaver somniferum

method from the standpoint of completeness of germination.
The position of the seeds, however, did affect the rapidity with

348 BOTANICAL GAZETTE [DECEMBER
which germination took place in the icebox, as will be shown in
the following section.
RAPIDITY OF GERMINATION

Under favorable temperature conditions, five days were required

for germination tests of balsam and cypress seeds; six days for

cosmos, marigold, pink, portulaca, and zinnia; eight days for
California poppy, candytuft, mignonette, and opium poppy (Papaver

N
LN

PER CENT
Q
9
EF 775

>_<

>
o

Fic. 5.—Average rate of germination of three lots of balsam seeds

somniferum); ten days for nasturtium, other species of poppy,
petunia, snapdragon, and sweet pea; twelve days for pansy; and
fifteen days for larkspur. For the germination of strong rapidly
germinating lots of seeds, less than the number of days indicated
is required. On the other hand, sometimes a very poor lot of
seeds or a lot which, although producing vigorous seedlings,
germinates slowly, may continue to germinate gradually for a few
days longer than indicated. The warmer the temperature within
the limit for complete germination, the more rapidly germination
took place. A decrease of a few degrees from any given tempera-
ture usually retarded germination more than an increase of the

1921] HARRINGTON—GERMINATION 349
same number of degrees hastened it. This dependence of the
rapidity of germination upon temperature was much more marked
with some kinds of seeds that with others. Figs. 5-8 show the
average rates of germination at different temperatures of a number
of different lots each of balsam, cypress, snapdragon, and larkspur

Phe

3 a pas ee
oa guleeescsy se AL
——
G y
yey
60 |}————_ b
y \y
+) AY
h ¢
tit ry
K > /
Ny
y | f
da
« Y
se
20
20
40
Oo
8 x % % %» f NX
Ny 24S ad
Fic. 6.—Average rate of germination of two lots of cypress seeds

seeds, and illustrate differences in sensitiveness to temperature
conditions. Fig. 5, for balsam, is typical also for mignonette,
petunia, and portulaca, in so far as the range of temperatures for
complete germination is the same. Cypress seeds (fig. 6) ger-
minated more rapidly than any other kind, and almost as rapidly
at 15° as at 30°C. Fig. 7, for snapdragon, is typical also for

350 BOTANICAL GAZETTE [DECEMBER

nasturtium, pansy, and poppy seed. It shows an acceleration of
germination by temperatures which were above the maximum for
complete germination. In contrast with fig. 7, fig. 8 (for larkspur)
shows a retardation of germination as well as a great reduction in
total germination by a temperature only 5°C. above the optimum
for complete germination.

Pal
“ey

oe Ge

PER CENT
ry
x)
cs
ane

ees

ce
oy
nes

e
eee:

Fic. 7.—Average rate of germination of three lots of snapdragon seeds

The harmful effect of a high temperature on the germination
of nasturtium, pansy, poppy, and snapdragon seeds is shown by
the fact that all of these seeds germinated more slowly even during
the first few days with the temperature alternation 20°—30° C.
(not shown in fig. 7, but about equivalent in average temperature
to 22.5°C. constant) than at temperatures lower than 22.5° C.
Pansy and poppy seeds germinated even less rapidly at 20°-30°

tg2t] HARRINGTON—GERMINATION 351

than at 17.5°C. Exposure to 30° for only a few hours each day,
therefore, had a retarding effect on germination even during the
early days of the test.

A few cases of apparent influence of temperature upon germina-
tion require special mention. California poppy seeds germinated
much more rapidly and somewhat more completely when the
chamber was heated to 30° and allowed to cool very slowly to
room temperature than with any of the other conditions of either

Fic. 8.—Average rate of germination of three lots of larkspur seeds

constant or alternating temperatures used in the series of tests
made in 1912.

The cypress seeds were infected with a “‘damping-off’’ organism, «
which destroyed some of the germinated seeds almost as soon
as germination began in the tests which were conducted at high
temperatures. Some of the nasturtium seeds were badly infected
with organisms of decay and with parasitic nematodes, which
affected germination more seriously at the higher than at lower
temperatures. To avoid difficulties of this kind, so far as possible
all sorts of seeds should be tested at temperatures as low as are

352 BOTANICAL GAZETTE [DECEMBER

consistent with the nature of the seeds in any given case. It is
possible also that effective sterilization of the seeds before placing
them in the germinator in some cases would alter the conclusions
as to optimum temperatures for germination.

The two lots of petunia seeds tested in 1912 germinated some-
what less completely with either of the constant temperatures
20° or 28° than with certain of the alternations of temperatures,
especially 20°-30° C. The petunia seeds used in the tests which
were made in 1914, however, germinated as completely with any
constant temperature from 17.5° to 30° as with the temperature
alternation 20°-30°C. In these tests the highest percentage of
germination obtained occurred with the constant temperatures
25° and 30°. In testing petunia seeds for germination, probably
the most uniformly good results would be obtained with a constant
temperature not warmer than 25° or cooler than 22.5°, or with
the temperature alternation 20°—30° C.

From 4 to 10 per cent of the sweet pea seeds remained hard
at the expiration of the germination tests at different temperatures.
No effect of temperature upon the softening and germination of
these seeds was noticed. .

RAPIDITY OF GERMINATION IN ICEBOX.—In the icebox the first
larkspur seeds germinated during the tenth day, the first poppy
seeds during the sixth day, and the first snapdragon seeds during
the twelfth day. With each kind of seeds, the progress of
germination in the icebox was slow. Four weeks were required
for a germination test of one lot of larkspur, and three weeks for
a germination test of the other two lots of larkspur and some of
the lots of poppy. The snapdragon seeds were kept in the icebox
over five weeks. At the end of this time germination had prac-

“tically ceased, but the total percentage of germination (38 per cent)
was still but little more than one-half as great as 17.5° C. (67 per
cent). The majority of the snapdragon seeds which germinated
in the icebox germinated between the twentieth and thirtieth days
of the test.

The germination of larkspur no. 250585 began on the eleventh
day and was complete in twenty days. At the same time no
seeds of larkspur no. 250500 germinated until the nineteenth day,

1921] HARRINGTON—GERMINATION 353

and germination of this lot continued through the thirty-first day.
The rates of germination of these two lots of seeds in the icebox

1éE%
of
rd
82
2 LZ
ad
ay sz | 4
se | 8
2? | 8
5
SS ee [=m
Sw . ad
Ra 7] a}
Ss Saad me
°o
~ se 2
NN x 2
3 ag oe &
~
\ ms goes ‘S
of qa
°o
\ te
\ aie &
Po 2
—
eG
z
NSD
as $7 7
a :
cS wee a
Fr 3
nw, a oe.
~
—s
2 2/
ae
4/
Of
NY ‘ < in 9 Ss 9 9 sos
S 6-6 FG 58 5.4%
Lu LNFI2 Fe

are shown graphically in fig. 9. Similar but less striking differences
occurred in the rates of germination in the icebox of different lots
of poppy seeds of each of the three species tested.

354 BOTANICAL GAZETTE [DECEMBER

RAPIDITY OF GERMINATION BETWEEN AND ON TOP OF BLOT-
TERS.—In 1914 the poppy seeds were tested simultaneously
on top of blotters and between blotters. Except in the icebox, the
position of the seeds did not affect the rapidity of germination.
In the icebox Papaver somniferum, two lots of P. rhoeas, and one
lot of the undetermined species germinated much more rapidly
between blotters than on top of blotters, while there was no differ-
ence with the other two lots. The greatest difference was with

ae BLOT Eee —
‘ “ee t' * a Pn a
§ or Jy ye
= JO : of
S #0 FP AGE IESG rs

ry %
eo hd Zz a
Ny
SO a att!
a4 AZ

o 2 Se SS se 8 Sy SK

bs he 2 me ss,

Fic. 1o.—Average rates of germination in icebox of six lots of poppy seeds,
between blotters and on top of blotters.

one lot of P. somniferum, only 5 per cent of which germinated in
the first seven days when on top of blotters, in contrast with 51
per cent between blotters. As the temperature of the icebox was
very cool, the further reduction of temperature on the surface
of the blotters by evaporation probably was sufficient to retard
the germination of these lots, and also may explain the lower
total germination on top of the blotters. Fig. 10 shows the average
rates of germination in the icebox of the six lots of poppy seeds
which germinated more rapidly between blotters.

1921] HARRINGTON—GERMINATION 355

Discussion

It is evident from the foregoing facts that the use of warm
temperatures usually increases the rapidity of germination of the
species investigated, but that comparatively low temperatures
are more favorable for completeness of germination. In conduct-
ing germination tests of each species, a temperature should be
used which is warm enough to accelerate the progress of germina-
tion as much as can safely be done. At the same time, it should
not be warm enough to prevent the germination of any viable
seeds, or to encourage more than is necessary the development of
microorganisms.

When the germination temperature is too warm, frequently the
germinated seeds make but little growth, and it is impossible to
judge the comparative vigor of different lots of seeds. Sometimes
weak seeds of little value will germinate when a warm temperature
is used, and will then appear to as good advantage as other strong
vigorous seeds. If the germination tests are made with a more
favorable temperature, both the strong and the weak seeds will
germinate, but in this case the difference will be obvious at once.
In this case some seedlings make rapid vigorous growth and are
normal in appearance, while others have a watery translucent
appearance, grow very slowly, and sometimes have begun to decay
before emerging from the seed coat. On the other hand, too
cool a temperature decreases the germination, increases the time
required, increases also the difference in time required by different
lots of seeds of the same species, and thus makes uniform procedure
with the different lots impossible. This condition is well illustrated
by larkspur samples no. 250500 and no. 250585 (fig. 9).

In conducting germination tests of some of the kinds of seeds,
considerable latitude is permissible in deciding upon the tempera-
ture to be used. With certain other kinds, as larkspur, the tempera-
ture requirements for completeness and rapidity of germination
fall within narrow limits.

The substratum should be such as to furnish abundant water
to the germinating seeds without limiting the supply of oxygen.
For this purpose folded blotting paper well moistened with water

356 BOTANICAL GAZETTE [DECEMBER

is favorable. Most seeds of medium size can safely be tested
between folds of blotting paper. Very small seeds do not hold
the separate folds of the blotting paper apart so as to allow circula-
tion of air between them. To insure a sufficient supply of oxygen,
such seeds should be tested on top of the moist blotting paper.
Candytuft seeds were tested on top of the blotting paper, not
because of their size, but because of their mucilaginous covering,
which softens when the seeds are wet and sticks the seeds insecurely
to both the upper and lower layers of the blotting paper, thus increas-
ing the danger of loss or displacement of the seeds when the blotters
are opened to count the germinated seeds. Pansy seeds have a
mucilaginous covering similar to the covering of candytuit seeds
and may well be tested on top of blotting paper, instead of
between blotters as in this investigation. Large seeds, such as
sweet pea and nasturtium, should be tested between folds of moist
canton flannel or other similar material, instead of in moist blotting
paper, because the cloth folds around each seed and supplies
moisture to a larger portion of its surface than the blotting paper
does.

The seeds should be carefully distributed upon the substratum
so that no two seeds touch each other. This guards against the
spread of microorganisms, and is of special importance with seeds
which are infected with such organisms as those which cause the
*“‘damping-off”’ of seedlings.

Table IV shows the conditions which are recommended for use
in making germination tests of the kinds of flower seeds included
in the investigation, and the number of days necessary for a pre-
liminary estimate of the germinating capacity and for complete
germination. The time allowed for preliminary estimate of each
kind is the number of days required for the germination of approxi-
mately three-quarters (actual proportions in this investigation
varied from 0.7 to 0.9) of the seeds of that kind which are capable
of germinating under the conditions indicated. The temperatures
given are those which it is thought will give best results with each
kind of seeds when both completeness and rapidity of germination
are considered. With many lots of seeds germination will be com-

1921] HARRINGTON—GERMINATION 357

plete in fewer days than are indicated for the completion of the
test, and perhaps in exceptional cases a few days longer will be
necessary.

Petunia seeds are the only kind for which an alternation of
temperatures is recommended, although sweet peas also will
germinate as well at 20°-30°C. as with a constant temperature.

TABLE IV

CONDITIONS RECOMMENDED FOR USE IN MAKING GERMINATION TESTS

No. OF DAYS FOR
SEEDS SuB- TEMPERATURE
icemreeaci: Preliminary | Complete
estimate test’
IT A oe AEN a on gee ea BB* 20°C 3 5
iornia Downy. | co BB 20° 3 8
RAYON ee TB 20° 3 8
ROS oe eo ee ee ar BB 20 3 6
TON ee a TB 20° 2 5
ERONNON Sc a BB is” 8 15
POST 8 a ee BB 20° 3 6
Minnonette: 6 ae BB 20° 4 8
MaRS Oo oe . ne 7 tO
beta ky APRA WEL enees eas TS: rig 6 12
20°—30°
stig ee emer yee oe TB { 22.°C Mt 5 e
Be Ce rer ae PEO NUYS Ea Bk es a TB 2
Papaver somniferum................ TB 15° 4 8
Winer poppies.) sce ee TB 1s 5 10
bak ee ee nee TB _ 20° 3 6
ORDUIRCON i oc ak ee: TB 17.5° 6 10
fo]

Ai oe ee ee
Ret ee tr BB 20 3 6

fa oe used in this column indicate; BB, between blotters; TB, top of blotters; C, cloth (canton
nnel),

} Either temperature condition may be used, but 20°-30°C. is probably preferable for petunia.

Petunia seeds will germinate almost as well, and frequently quite
as well with the constant temperature 22.5° or 25°C. as with the
alternation 20°30° C., and either of these constant temperatures
may be used for approximate results when it is inconvenient to
Maintain the two temperatures 20° and 30°C. Nasturtium,
pansy, and snapdragon seeds will germinate about as completely
(although more slowly) with the constant temperature 15° as
17.5°C. These kinds may be tested also at 20°C., although a

358 BOTANICAL GAZETTE [DECEMBER

lower temperature is somewhat more favorable. Such considera-
tions make it possible to test all the kinds of seeds investigated
with approximately optimum conditions by maintaining only
three different temperatures. These three temperatures may be
either 15°, 20°, and 22.5", or 15°, 20°, and 30° C., according as
petunia and sweet pea seeds are to be tested with a constant tem-
perature (22.5°) or with an alternation of temperatures (20°-30° C.).
It should be emphasized, however, that probably more uniformly
good results would be obtained by using for each species the tem-
perature indicated in table IV.

GREENWICH, CONN.

SUBTERRANEAN ORGANS OF BOG PLANTS
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 288
Frep W. EMERSON
(WITH ELEVEN FIGURES)

Introduction

There has been much research on the subterranean organs of
plants from many standpoints. The analytical study of these
organs as they grow in nature, however, has chiefly been limited
to comparatively recent work. In 1899 and 1900 HircHcock (4)
published results of work done on the Kansas flora, in which were
brief descriptions of the underground parts of a considerable
number of native plants, with notes on habitat and length of life.
CANNON (1, 2) in 1911 and 1913 added greatly to our knowledge of
the behavior of roots in the soil, showing that some of the current
ideas have at best been incomplete, and that in the desert there is
a wide variation in root behavior. More recently a number of
papers have appeared adding information about the root and
rhizome systems in a variety of habitats. Among them are papers
by Haypen (3), Marke (6), Puttinc (7), and WEAVER (o9, 10).

The present paper deals with work carried on in an attempt
to discover, first, the exact behavior of the underground parts
of plants growing in peat bogs, and to some extent to compare these
organs with those of the same species growing in mineral soil;
and second, to determine as far as possible the factors involved
in any peculiarities in behavior noticed.

While there are many references in the literature to the com-
paratively shallow roots in swamp lands, it seems that no one has
gone into detail in determining just how shallow the roots and
rhizomes are, nor with a few exceptions have the biological relation-
ships of these parts been analyzed. Yapp (12) has described some
of the relationships of roots and rhizomes in the fen, and SHERFF
(8), in his analysis of the subterranean organs in Skokie Marsh,

359] [Botanical Gazette, vol. 72

360 : BOTANICAL GAZETTE [DECEMBER

has gone into somewhat greater detail. In neither of these papers,
however, is work reported on the typical peat bog plants.

The main station for this study was Cedar Lake, at Lake Villa,
. Lake County, Illinois. Supplementary work was carried on in
bogs at Miller and Hillside, Indiana, and in a fen at Wolf Lake,
Indiana. Cedar Lake is located about five miles south from the
Wisconsin line and twenty-two miles west from Lake Michigan.
It is situated in the Valparaiso morainic system (5) in a consider-
able depression in the drift. The western border of the lake is deep
and is covered by a floating mat of fibrous peat, while the north
and east sides are shallow, and the vegetation passes from the usual
hydrophytic forms in the water to shrubs, sedges, and grasses on
the shores. This gives opportunity for comparing certain species
as they grow in both peat and mineral soils, but with other condi-
tions as nearly the same as is possible to find them in nature. The
bog under consideration is of crescent form, fringing the west end
of Cedar Lake, and is about 200 m. in width at its widest part.
It is composed of a floating mat of peat that is only slightly decom-
posed, except where it comes in contact with the clay basin at its
landward margin. Here it has decayed, forming a hummocky
black soil. Judging from its small size, the fact that it has made but
a beginning in covering the lake although it is evidently making
measurable progress, and the absence of all trees with the exception
of a few young tamaracks, it seems evident that this bog is geo-
logically very young. When compared with the vegetation of other
bogs of the region, the plant life of this bog is obviously in the
very early stages of plant successions, and it is inconceivable that
it dates back to glacial times. Thus the supposition that all bogs
are relicts from the glacial period seems less plausible.

Field study

In order to determine the exact form and physical relationships
of the roots and rhizomes of bog plants, the preliminary work under-
taken was the mapping of these parts in situ. The organs in
question, some of which were very tender, were followed with the
finger tips and then laid bare by the removal of all the material above
them. Careful measurements were taken and the maps were made

1921] EMERSON—BOG PLANTS 361

to scale on coordinate ruled paper (figs. 1, 3, 4, 6). In this work
_ it soon became evident that, with the exception of a few species,
living plant parts were very rare below a certain comparatively
slight depth, and that each species had its own characteristic
range of depths. In most cases the roots and rhizomes maintained
almost the same level throughout their length. Hence in mapping
it was necessary to show only the horizontal arrangement of the
organs in question, stating the depth from the surface or the
relation to the water table. Since the mat is held up by its own
buoyancy, the surface remained at practically the same level

ae ne a
es ne ee.
Crease ae se
oy : 0 4 = : :
> og P Z
4% PI “6
>,
ce
ey ras
ry
ce
50 cm. -

Fic. 1.—Aspidium Thelypteris, map of rhizome system: L, living attachment to
older part of system; D, dead tips of rhizomes; F, foliage leaves; solid black lines,

ving rhizomes; note numerous dead rhizome tips, represented by cross lines on
white ground, in older parts; dying behind the dichotomous branches leaving them
independent is a very common means of multiplication in this fern; depth 4-6 cm.

throughout its extent and throughout the growing season. This
distance from soil surface to water table was approximately 6 cm.
As may be noted in the maps, the underground parts of bog plants
are remarkably straight when compared with those of upland plants.
oubtless this is largely because of the lack of mechanical inter-
ference to the growing parts by the spongy peat. The more impor-
tant species represented in this bog are as follows.
Sphagnum.—This plant grows abundantly over most of the
floating mat, especially toward the lakeward margin. It was
found to be propagating vegetatively by growing above and
dying. below. No other means of propagation was found. It
appeared to remain alive to a depth of 3-4 cm.

362 BOTANICAL GAZETTE [DECEMBER

Aspidium Thelypteris—This species was studied in both bog
and swampy mineral soil. The rhizomes were found to be always
horizontal. The depth was 2-6 cm. in bog soil, and 1-6 cm. in min-
eral soil. In no case were living parts found below water. The
roots were almost horizontal when near the water table, but nearly
vertical and going down to 15-17 cm. deep in a substratum that was
only moist. No difference of any sort was apparent in peat and
mineral soil. Fig. 1, which is a map of most of the rhizome

Fic. 2.—Larix laricina with roots showing horizontal position; inset, young
ieediing’ and Hpi three or four years old showing tap root becoming horizontal;
maximum depth 6c

system of one plant, shows that in the older parts there are numerous
dead rhizome tips and few leaves, while in the younger parts the
plant is vegetating very freely. The older parts were much dis-
colored and too brittle to trace farther than is shown in the map.

Larix laricina (fig. 2).—The larch had no tap root, all the roots
being horizontal and above the water level, except where the
weight of the tree forced them deeper into the peat. All living
roots were 6 cm. or less in depth. There were only a few dozen
comparat'vely young larches in the bog in question. No other
tree species was found.

1921] EMERSON—BOG PLANTS 363

Typha latifolia.—The rhizomes of this species assume about the
Same depth in mineral or peat soil. Those measured varied
from 15 to 30cm. deep in peat, and from 12 to 25 cm. deep in
mineral soil. The roots extended diagonally or vertically down-
ward. The deepest extended far below water in both types of
soil. A few of the vertical roots were found exceeding 60 cm. in
depth. On account of the turbid water they could not well be
followed to a greater depth.

Sagittaria latifolia.—This species is not very common in the bog,
but is included because it also grows outside of the bog and affords
opportunity for comparison in the two habitats. While there is
~Lupaners variation in the depth of various parts of a given

50 cm. ef L

3:—Carex filiformis, map of rhizome system: A, aerial stems; L, living
Breda to older rhizome; solid black line, living erect depth 8 cm. at aerial
stems and going down to 30 cm. between aerial parts.

thizome system, corresponding parts were found to assume about
the same depth in various soils. The aerial parts arise from the
thizome at about 4-6 cm. deep, while at other places the rhizome
gradually descends to depths of ro cm. or more. The root behavior
is almost identical with that of Typha latifolia.

Scirpus validus—The rhizomes assumed a depth of 12-15 cm.
in all soils where the species was found. A few of the roots
extended downward to a depth of 30-40 cm. Nearly all of the roots
were vertical, hence the entire subterranean system was below
water. This bulrush was fairly common along the lakeward margin
of the bog as well as in fens.

Carex filiformis—This sedge was found in the bog only. Its
roots and rhizomes varied in depth from 5 to 30cm. The roots
were approximately horizontal (fig. 3).

364 BOTANICAL GAZETTE [DECEMBER

Pogonia ophioglossoides (fig. 4).—While this orchid plays no pro-
nounced part in the building of the bog, it is included on account of
the peculiar character of its subterranean system. This is made
up of a simple but comparatively extensive root system from which
the aerial parts grow. This plant has no rhizome, although the
root behaves in a manner similar to a rhizome and forms an effective
means of vegetative propagation. Branches proper are lacking in
the roots, but one or two new roots are likely to arise adventitiously
from the base of each aerial shoot. This entire root is 5-6 cm.
deep, which is just at the surface of the water in the bogs studied.

Calopogon pulchellus——In contrast with Pogonia, this orchid
has very little root system, the chief underground part being a
small bulb. The bud of this bulb frequently divides, making two

ee «5
,

50 cm.

| Aa EEL —)

Fic. 4.—Pogonia sae ta SRD of root aye A, aerial stems; R, root;
plant propagated b ts instea t bog plants; depth 6 cm

new plants, which, however, are likely to remain attached to each
other, hence this is a poor means of disseminating the species.
The few simple roots and the bulb structures were found to be
dead at about 6 cm. deep, hence no living parts were found below
the water.

Betula pumila.—The dwarf birch grows obliquely or vertically
upward, putting out roots at various levels in the peat. These
roots assume an approximately horizontal position. They were
found at various levels from 6 to 18 cm. deep.

Sarracenia purpurea (fig. 5).—This species has a vertical stem,
and distorted, usually vertical adventitious roots growing out
wherever the stem is covered with peat. All structures die at the
water surface.

_ Drosera rotundifolia.—This plant behaves similarly to Sarra-
cenia, except that its living parts do not extend deeper than 2 or

1921] EMERSON—BOG PLANTS 365

3 cm., and there are not more than three or four feeble, unbranched
roots living at any time. Although a comparatively small plant,
it appears to be able to grow upward rapidly enough to keep from
being covered by the Sphagnum in which it often grows.

Lathyrus palustris (fig. 6).—The rhizomes and roots are hori-
zontal in this species, and were not found living below water.
The rhizomes were mostly about 5 cm. deep. The roots were few
in number, short, and only slightly branched. Those around the
aerial stems had numerous large tubercles containing bacteria.

Fic. 5.—Sarracenia purpurea, entire root system; stem and roots dead below
depth of é cm.; roots in normal posi

Decodon verticillatus—This species is the most prominent
pioneer extending the floating mat out over the lake. Wherever
the stems come in contact with water, large amounts of cortical
aerenchyma form and numerous adventitious roots grow down.
Considerable quantities of peat cling to this mass of stems and
roots, and thus a floating substratum is formed on which other
plants soon begin to grow. Among the most common of these are
Sphagnum, Aspidium, and Scirpus. The greatest depth to which
the roots of Decodon descend in the water was not determined
accurately, but it was found that they attain at least a depth of
more than 40 cm.

366 BOTANICAL GAZETTE [DECEMBER

Vaccinium macrocarpon.—Where the prostrate stems of the
cranberry come in contact with the moist peat, numerous short
adventitious roots appear growing diagonally downward or almost
horizontal. As the peat forms above and the roots and stems are
weighed down to the water level, they die at the surface of the
water. This species, growing with Aspidium Thelypleris, forms a
tough woody network over a considerable part of this bog.

Menyanthes trifoliata.—The rhizome of this plant assumes an
approximately horizontal position from 3 to 9 cm. deep, while the
roots may either be horizontal or vertical. The roots were found
as much as 12cm. deep. They were few in number and compara-
tively short but much branched.

Eupatorium perfoliatum.—The base of the stem of this species
assumes an approximately horizontal position near the soil surface

Fic. 6.—Lathyrus palustris, map of rhizome system: L, living ena A,
aerial stems; D, dead rhizome tips; solid black lines, living rhizomes; depth 6

and the roots grow almost horizontally from this. In the bog the
roots were found to reach a depth of 4-6 cm., while in mineral
soil where the water table was much lower they reached down to
depths of 5-10 cm.

It should be noted that a very high percentage of all the living
plant tissue in the bogs studied is above the water level. The
part above water usually consists of a mat about 6 cm. thick, made
of a coarse feltlike tangle of living roots and rhizomes largely of
Aspidium, Carex, Vaccinium, and Menyanthes, and often a dense
growth of Sphagnum. It is difficult to penetrate this tough mat,
while just below the water level a sharp contrast appears. Here a
fibrous, light brown peat is found in which the dead parts of these

same species can often be recognized to considerable depths.
_ Almost the only living parts encountered are occasional roots oF
rhizomes of Typha, Sagittaria, Scirpus, or Eriophorum.

1921] EMERSON—BOG PLANTS 367

MarkKLeE (6) working in New Mexico, and WEAVER (9, 10) in
the prairies, have noted that two dominant species in an associa-
tion are not likely to have their roots so placed as to have any
marked subterranean competition. This is obviously not the case
in the main parts of this bog flora, where two codominants, Vac-
cinium macrocarpon and Aspidium Thelypteris, have practically the
same level, and together dominate the greater area of the bog.
Neither of these two dominant species seems to be overcoming the
other. Mingled with these are a number of less important species
also at the same level. On the other hand, the deep-rooted forms
in which there is no competition are in no case crowding out the
shallow rooted species.

Aerenchyma is very common both above and below the water
table. Roots and rhizomes which grow below water are all very
rich in air tissue, with the exceptions of Betula pumila and Salix
spp. In these species no aerenchyma was found in any of their
parts, nor, with the exception of Decodon verticillatus, was it found
in any woody perennial examined. In most cases herbaceous
species have a great deal of aerenchyma.

Tests for H ion concentration in the soils were made by means
of the colorometric indicators made by the La Motte Chemical
Products Company. The records were made in terms of specific
reaction (11). The tests were made in the white porcelain “spot
plates,” such as are commonly used in the chemical laboratory.
By means of pipettes the water to be tested was drawn off from
the absorbing parts of the roots. In all cases fruiting or flowering
plants were used. Both pipettes and spot plate were thoroughly
rinsed in the water to be tested before beginning each test.
series of samples was taken across the bog from the lakeward margin
toward the landward side. The water of the lake was uniformly
30 alkaline. The reaction on the floating mat gradually changed
from alkaline to neutral, and finally reached 10 acid, 2 or 3 m. from
the lakeward margin. This reaction was uniform across the entire
mat until the decaying peat was reached on the landward side.
Here the acidity decreased until it reached neutrality at a point
where the mat was so decomposed that it would no longer bear the
weight. It was not possible in any case to discover a difference in

368 BOTANICAL GAZETTE [DECEMBER

reaction in the water drawn from the immediate surface of the roots
and that taken from the peat near by. Hence it seems that all
roots in a given area are subject to approximately the same soil
reaction. Members of a given species, however, often showed con-
siderable latitude in tolerance to soil reaction. The widest varia-
tion found was that of Larix laricina. At Mineral Spring, Indiana,
in a very old bog in which the peat has become casas
decayed, the reaction about its rootlets was 10 alkaline; at

side, Indiana, in a mature bog of fibrous peat, 300-1000 ae
and in the comparatively young mat at Cedar Lake, 10 acid. No
marked differences could be seen in subterranean systems of
members of the same species growing in peat and mineral soils, or
in various natural concentrations of H and OH ions.

Other species which showed a narrower range of tolerance to
reaction follow, with the extremes of reaction found in each.
Water squeezed from Sphagnum had a specific acidity of 100
to 1000; Aspidium Thelypteris, Scirpus validus, and Betula pumila
all varied from ro alkaline to 10 acid; Sarracenia purpurea, Drosera
rotundifolia, and Vaccinium macrocarpon varied from neutral to
300 acid. The peat about the roots of Decodon verticillatus at the
margin of the mat was approximately neutral, while the lake water
into which this species was migrating was 30 alkaline.

Experimentation

In order to determine the factors involved in the horizontal
placing of roots in bogs, the following experiment was carried
out. Galvanized iron boxes, 10 cm. X15 cm. X55 cm., were made
with the bottom and one side replaced by a diagonal pane of glass.
This glass was covered on the outside by a piece of galvanized iron
which could readily be removed, making it easy to make observa-
tions of the roots, but at the same time keeping them protected
from the light except during examination. In certain parts of this
experiment, as indicated later, a fixed water table was maintained
by keeping the boxes in pans of water of proper depth (figs. 7, 8)-
All metal surfaces were given two coats of Acme asphalt varnish.
Various germinating seeds were planted in these boxes. The most

1921] EMERSON—BOG PLANTS 369

significant results are shown in figs. 9-11. Distilled water was
used throughout the experiment for watering the seedlings and
maintaining the water level. This distilled water had a reaction of
approximately 1 (neutral), although in some cases it showed a
slight trace of acidity from carbonic acid. All the peat maintained

Fic 8.—Growing boxes used in experimental work: fig. 7, growing box with
Sit nda side facing camera (removable sheet iron false side is in place covering
glass); fig. 8, growing box similar to that in = 7 placed in pan containing water,
thus maintaining fixed water level in growing box

a specific acidity of 3 throughout the experiment. The garden
soils varied from specific reaction 1 to specific alkalinity 10. This
last reaction was reached near the end of the experiment in the wet
garden soil. The experiment was carried on for about two months
during February, March, and April, 1921, in the cool room of the
greenhouse. At the end of this period the plants were removed

37° BOTANICAL GAZETTE [DECEMBER

from the soil and characteristic specimens, showing as far as
possible the extremes of size and form, were photographed.

9
& pte
tH mas

at
'Y'"S‘*N’OOVSIHD - - ANVdWOO nf aang
‘ 4 , 1 4

weud ous Sougans pase Wie. Ee Mies + —
~ = ANVAWOS 9 HVWHOS <<
: ii eye ee
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Cl ee
eA
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é
AHS
4

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VdWOO 9 YVVHOS
Seer oe

it 5 Mice RIE
Fics. 9-11.—A, seedlings grown in moist garden soil; B, in moist brown fibrous

5 a
put seyddng Ksoies00e7

surface; fig. 9, Pinus Strobus; fig. 10, Abies balsamea; fig. 11, Cai excelsa
1. Pinus Sirobus (fig. 9 A, B).—In both moist garden soil and
moist peat the tap root assumed approximately the vertical position,

1921] EMERSON—BOG PLANTS 371

deviation from this direction being chiefly from the interference
of the diagonal glass side of the growing box. It is also noteworthy
that in both of these cases laterals were lacking. In garden soil
in which a water table was kept, capillarity caused the water to rise
until the soil was practically saturated to the surface. Only one
pine seedling lived throughout this part of the experiment. A
number of seedlings started to grow, however, and all behaved in
the same way. All the tap roots showed a slight tendency to pene-
trate the soil, but the plants soon fell over and the roots grew in an
approximately horizontal direction, producing no laterals (fig. 9 C).
Those growing in peat in which a water level was kept behaved in a
still different manner. On account of the fibrous spongy structure
of the peat, aeration was possible to the water surface. The tap
roots grew downward about as in the moist garden soil and peat,
although somewhat less rapidly. The most obvious difference
began to appear when the tips of the tap roots reached the water
level, when growth almost completely ceased. In a few cases the
roots continued to grow slowly for some time after reaching the
water level, but in all cases these longer roots died back to about
the surface of the water. Strong laterals always appeared and
took approximately the horizontal position. The study of this
species was suggested by the statement made by PuLtinc (7) that
Pinus Strobus has ‘‘a deep rigid root habit.”’ In examining the
root systems of this tree at various ages in the Hillside bog and at
Mineral Spring no root was found extending more than a few
centimeters deep and all were horizontal. From this experiment
and from field observation it is obvious that the tap root is
ephemeral under bog conditions, and that very shallow horizontal
laterals make up the entire root system.

2. Abies balsamea (fig. 10).—Under all the conditions of this
experiment the roots grew downward and all were putting out
laterals at the end of the experiment. At the water surface the
roots behaved as in the case of Pinus Strobus.

3. Picea excelsa (fig. 11) Throughout there was evident a
decided tendency for the roots to assume an almost horizontal
position. In some cases the roots penetrated somewhat below the
water surface without showing any ill effects, although the rate of
growth was greatly checked on entering the water.

372 BOTANICAL GAZETTE [DECEMBER

Discussion

A comparison of the action of the roots of seedlings under
experimental control with observations in the field shows that there
are four general types of behavior of subterranean organs in these
bogs.

1. The roots and rhizomes assume an approximately horizontal
position above the water table. Typical forms are Aspidium
Thelypteris, Picea excelsa, Larix laricina (fig. 2), Carex filiformis,
Pogonia ophioglossoides, Potentilla palustris, Lathyrus palustris, and
Vaccinium macrocar pon.

2. The tap roots of the seedlings die at the water surface and
horizontal laterals appear above. Examples are Pinus Strobus
and Abies balsamea.

3. All underground parts are approximately vertical and die
near the water surface, usually with non-horizontal laterals or

adventitious roots appearing above, as in Sphagnum, Calopogon
pulchellus, Sarracenia purpurea (fig. 5), and Drosera rotundifolia.

4. The rhizomes and roots are able to grow under water.
Important species are Typha latifolia, Sagittaria latifolia, Scirpus
validus, Eriophorum, Betula pumila, and Decodon verticillatus.

While doubtless there are many factors influencing the location
of roots and rhizomes in bog soils, it becomes evident that the
two most potent are hereditary tendencies and water level. Rhi-
zomes of certain plants, such as Typha, assume a depth apparently
determined by heredity, which places them below the surface
of the water. Such plants as can readily endure submergence are
able to persist in the bog unless other factors interfere. Obligate
deep-rooted plants which are intolerant of submergence are elimi-
nated by water from this flora. Rhizomes of certain other species,
as for example Aspidium Thelypteris, are in all cases superficial,
thus permitting their development above water. On the other
hand, the roots especially seem to respond rather readily to the
water surface. A number of species have only shallow roots
where the water table is high, but deeper ones in most peat or moist
mineral soil. This was found to be especially well illustrated by
Aspidium Thelypteris, Pinus Strobus, and Acer rubrum; hence it
is apparently not the quality of the soil but the presence of water

1921] EMERSON—BOG PLANTS 373

that induces shallowness. Doubtless the lack of oxygen plays a con-
siderable part in checking growth under water. It is possible that
bog toxins may in part be responsible for the poor development or
in some cases even the death of the roots of certain species.

Summary

1. Subterranean systems of plants growing on floating mats
were found to be very superficial, nearly all the living tissue being
above the level of the water.

2. No evidence was found to suggest that acidity or toxins are
involved in the shallowness of these organs. Water level was
apparently the important factor, aside from hereditary tendencies
in certain species.

3. Roots of codominants were in close — without
apparent damage resulting to them.

4. Three types of behavior were noted, sasha in the super-
ficial placing of the living parts of bog plants: (a) the parts assume
the horizontal position above the water level; (6) the tap root is
ephemeral in the bog and is replaced by horizontal laterals; (c) the
roots are all vertical and die at the water surface.

5. Certain plant parts ' were found to be able to thrive under the
water in the bogs.

6. There is no apparent marked difference in the subterranean
organs of a given species growing in a bog and in comparable con-
ditions in mineral soils.

I wish to express my appreciation to Dr. H. C. CowLes and
Dr. Geo. D. Futter for encouragement and helpful suggestions
during the progress of this work.

PENN COLLEGE
Osxatoosa, Iowa
LITERATURE CITED
1. CANNON, W.A., The root habits of desert plants. Carn, Inst. Wash. Publ.
Tar. 20tt.
. , Notes on root variation in some desert plants. Plant World 16:
323-341. I9T3.
3. Haypen, Apa, The ecological subterranean anatomy of some plants of a
prairie province in central Iowa. Jour. Bot. 6:87-105. r1919.

374 BOTANICAL GAZETTE [DECEMBER

4. Hitcucock, A. S., Studies on decane organs. Trans. Acad. Sci. St.

Louis 9:1-8. thos: 102 131-142.

Hopkins, C. G., et al., Lake ae solle. Univ. Ill. Agric. Exper. Sta.

Soil Rept. no. 9. 1915.

. MARKLE, M.S., Root systems of certain desert plants. Bot. GAz. 64:177-
205. IQ17.

7. Putiinc, H. E., Root habits and plant distribution in the far north.
Plant World 21: 223-233. 1918.

8. aries E. E., The vegetation of Skokie Marsh. Bort. Gaz. 52:415-435.

9. Weaver, J. E., The ecological relations of roots. Carn. Inst. Wash. Publ.
286. I9I0.

, Root development in the grass land formation. Carn. Inst. Wash.
Publ. 292. 1920.

11. WHERRY, E. T., Soil acidity and a field method for its measurement.
Ecology 1: 160-173. 1920.

12. YAPP, R. H., Wicken Fen. New Phytol. 7:61-81. 1908.

MORPHOLOGICAL STUDY OF CARYA ALBA AND
JUGLANS NIGRA
THEO. HoLm
(WITH PLATES XV, XVI, AND ONE FIGURE)

The systematic position of the Juglandaceae has been somewhat
disputed, some workers having referred the family to the close
vicinity of the Anacardiaceae, although the floral structure is very
different, and the resiniferous ducts so characteristic of these are
totally absent from the Juglandaceae. Since the floral structure
has been incorrectly explained in American manuals, it is thought
advisable to redescribe this. Moreover, there are several points
with regard to the internal structure and the germination which
may be of interest to the student of plant morphology, besides that
the American representatives are very little known from this
particular point of view.

Flower

According to EICHLER,! the staminate flower of Carya (fig. 1) con-
sists of two prophylla (P), which grow together with the subtending
bract (L), thus forming a three-lobed involucre (figs. 2, 3) suggesting
that of Carpinus; there is no perianth. The stamens, two to ten,
have very short filaments, and are free (fig. 4). In the pistillate
flower (figs. 5, 6) the bract is much longer than the two prophylla
and the single, or very seldom two perianth-leaves (figs. 7, 8).
In other words, the staminate flower has a three-lobed involucre,
but no perianth; on the other hand, the pistillate has a very
rudimentary perianth, consisting of a single leaf, or very seldom
of two minute leaves.

This simple and natural explanation of the floral structure,
however, has been ignored or completely misunderstood by subse-
quent writers in this country. It is strange to see the incorrect
description that has been given in the treatments of the North

* EICHLER, A. W., Bliithendiagramme. 2:32. 1875.
375] [Botanical Gazette, vol. 72

376 BOTANICAL GAZETTE [DECEMBER

American flora. For instance, in Gray’s New manual of botany?
the staminate flower of the Juglandaceae is said to have “an
irregular calyx adnate to the bract,” and the pistillate flower to
have ‘‘a regular 3—5-lobed calyx adherent to the ovary.” Further-
more, under Carya the staminate flower is simply described as
“stamens 3-10; filaments short or none, free,’’ while ‘‘a. four-
toothed calyx; petals none” is attributed to the pistillate flower.

SARGENT® describes the staminate flower of Carya as follows:
“Calyx usually 2-, rarely 3-lobed, subtended by an ovate acute
elongated bract free nearly to the base, and usually longer than
the ovate rounded calyx-lobes.”” In the pistillate flower the calyx
is said to be ‘‘reduced to a single posterior lobe,” and the ovary to
be ‘‘inclosed in a perianth-like slightly 4-ridged involucre, composed
by the more or less complete union of an anterior bract and 2
lateral bractlets, adnate below to the ovary, unequally 4-lobed at
the apex.”

Britton‘ describes the staminate flower of Juglandales as
‘‘consisting of 3-numerous stamens with or without an irregularly
lobed perianth adnate to the bractlet,” and the pistillate “‘bracted
and usually 2-bracteolate with a 3-5-lobed (normally 4-lobed)
calyx or with both calyx and petals.”” Under Hicoria the staminate
flower is said to possess “‘a calyx adnate to the bract, 2-3-lobed or
2-3-cleft,” and the pistillate flower is described as ‘‘bract fugacious
or none; calyx 4-toothed; petals none.” This same description
is reprinted in the second edition of Brrrron and Brown’s [/lus-
trated flora.

By SMALL the staminate flower of the Juglandales is said to
possess “‘a 2~6-lobed calyx bearing several rows of stamens, or the
calyx obsolete,” while the pistillate flower is described as ‘‘consist-
ing of an involucrate incompletely 2-4-celled gynaecium: calyx
partially adnate to the gynaecium.”’ Under Hicoria the staminate

? Ropinson and Fernatp, A handbook of the flowering plants and ferns of the
central and northeastern United States and adjacent Canada. p. 330. 1908.

3 SaRGENT, C. S., The Silva of North America. 7: 1895.

4 Britton, N. L., Manual of the flora of the Northern States and Canada. 34.
ed. p. 322. 1907.

5 SMALL, J. K., Flora of the southeastern United States. 2d. ed. p. 332. 1913-

1921] _ HOLM—CARYA AND JUGLANS 377

flower is described as ‘‘a 3-lobed calyx,” and the pistillate as “a
calyx of 1 sepal adnate on the ovary.”

With respect to the flowers of Juglans, EICHLER describes the
staminate flower (fig. 10) as consisting of two prophylla (P), which
with the two to five perianth leaves grow together with the sub-
tending bract; the six to forty stamens have very short, free
filaments. The pistillate flower has a superior, four-leaved peri-
anth; the ovary, bract, and prophylla all unite together, their
edge being visible as an indented line below the perianth (fig. 13).
The staminate flower, therefore, has two prophylla and a two to
four-leaved perianth, which grow together with the subtending
bract; the pistillate has a superior perianth of four leaves, and the
subtending bract beside the two prophylla grow together with
the ovary.

As was the case of Carya, this very simple structure has been
completely misunderstood by subsequent writers in this country.
Rosinson and FEernaxp do not describe the staminate flower of
Juglans in any other way than ‘‘stamens 12-40; filaments free,
very short.’’ On the other hand, the pistillate flower is said to
Possess ‘‘a four-toothed calyx, bearing four small petals at the
sinuses.”

SARGENT attributes ‘‘a perianth sessile or pedicellate, three to
six-lobed in the axil of an adnate to an ovate acute bract free only
at the apex” to the staminate flowers. The pistillate flower is
described as being invested by a villous involucre adnate to the
Ovary, and formed by the union of the anterior bract, sometimes
free nearly to the base, and two lateral bractlets free only at the
apex, and variously cut into a laciniate border shorter than
the erect’ lanceolate calyx lobes inserted at the summit of the
Ovary.

By Brirron the staminate flower of Juglans is said to have a
“perianth 3~-6-lobed,” and the pistillate ‘calyx 4-lobed, with 4
small petals adnate to the ovary at the sinuses.’’ Smaxt describes
the staminate flower in the same manner, while the pistillate is
Said to have ‘the sepals adnate to the ovary.”

In “Flora of the District of Columbia and vicinity,’’published
under the auspices of the Smithsonian Institution (1919), no

378 BOTANICAL GAZETTE [DECEMBER

description is given of the floral structure, except that the fruit is
‘‘a nut inclosed in a shuck or husk, the meat or embryo
4-lobed.”
Carya alba
Root

The primary structure may be studied from the thin lateral
roots of the seedling. No secondary increase takes place during
the first season; thus the epidermis and cortical parenchyma remain
intact. The latter consists of about ten compact strata, and the
endodermis is very thick-walled, representing a U-endodermis.
A thin-walled pericambium of a single layer surrounds the pentarch
stele, in which thick-walled conjunctive tissue is much in evidence,
surrounding the vessels, and as a narrow group in the center of the
stele. On the other hand, increase in thickness is readily mene:
in the primary root of the seedling in its second year. In this
epidermis and the primary cortex have become thrown off, pee ne
by many layers of homogeneous, thin-walled cork of pericambial
origin. Inside the cork is a narrow zone of thin-walled parenchyma,
which surrounds a circular band of small strands of stereome
(fig. 9, St), supporting the leptome (ZL) of the secondary mestome
strands. There is now a continuous ring of cambium, from which
the secondary mestome is developed, and the thickness of the root
depends largely upon the presence of a very broad, central, thin-
walled parenchyma, a true pith, containing starch in abundance,
but no crystals.

The development of stereome in the root deserves attention,
since, so far as known, this tissue does not appear to be commonly
represented in roots. In Carya it is a secondary structure, which
seems to be the general case wherever it occurs in roots. As a
primary structure the stereome is extremely rare, known only in
a very few genera, Dirca, Anona, Celtis, etc., where it is developed
in the primary leptome.

STEM

The apical internode of the seedling is densely covered with
hairs of different types, unicellular, long, pointed, which are either
single or developed in tufts; and large, sessile, pluricellular, glan-
dular of peltate shape. The cuticle is smooth and the epidermis

1921] HOLM—CARYA AND JUGLANS 379

is quite thick-walled. The cortex is differentiated into a peripheral
sheath of collenchyma, three or four strata, and an interior of
thin-walled parenchyma, five to six layers. Rhombic crystals of
calcium oxalate were observed in the collenchyma, while aggregated
crystals occurred sparingly in the inner part of the cortex. The
phellogen arises in the hypodermal stratum of the collenchyma.
A thin-walled, starch-bearing endodermis surrounds a band of
small isolated strands of stereome, separated from each other by
natrow rays of parenchyma. The stele shows a continuous zone of
leptome, cambium, and hadrome in deep rays, accompanied by
many layers of libriform. A homogeneous, slightly thick-walled
pith, destitute of starch, occupies the central portion of the stele;
the pith is not septate.

In branches of the mature tree the cork appears in many
thin-walled strata; the stereome is well represented as several,
until seven, concentric bands of isolated strands, the result of one
season’s growth. Large rhombic crystals abound in the leptome,
and the hadrome is divided by broad tangential bands of moderately
thickened libriform. The very thick-walled, porous vessels so
characteristic of J uglans do not occur in Carya, and the pith is
nowhere septate.

LEAF

Viewed in superficial sections the ventral epidermis shows the
lateral cell walls prominently undulate, hairs and stomata being
absent. In the dorsal epidermis the lateral walls are less undulate,
but stomata and hairs are abundant; of these the former are all
of the same size, and surrounded by four to seven ordinary epider-
mis cells; the hairs are of the same types as observed upon the stem.

Viewed in transverse sections the cuticle is thick and smooth
on both faces of the leaf blade, and the outer cell wall of epidermis
is thickened. Large oil drops abound in the ventral epidermis. The
mesophyll consists of a typical palisade tissue of one stratum, cover-
ing a very open pneumatic tissue of three to five layers. Numerous
large cells containing aggregated crystals are’ scattered in the
palisade tissue, while single rhombic crystals abound in the pneu-
matic tissue, especially close to the veins.

380 BOTANICAL GAZETTE [DECEMBER

The midrib of the leaflet has a very thick-walled epidermis,
and a few hypodermal strata of collenchyma on both faces, border-
ing on a water-storage tissue with many aggregated crystals.
There is no endodermis, but a closed sheath of stereome, which
surrounds a stele of several collateral mestome strands, all of which
turn the leptome toward the periphery, and with the hadrome
bordering on a central pith. The pith is thin-walled, and contains
some few crystals, aggregated as well as single, rhombic. The
- much thinner lateral veins are more or less imbedded in the meso-
phyll, and contain only one mestome strand, surrounded by a
chlorophyll-bearing parenchyma sheath. The structure of the
rhachis and the petiole is identical with that of the midrib, thus
containing a typical stele of several mestome strands, a sheath of
stereome, and a cortex of which the peripheral strata are collenchy-
matic.

Juglans nigra
SEEDLING

In the Juglandaceae the cotyledons are hypogeic in all the
species examined, with the exception of Pterocarya caucasica C. A.
Mey., which germinates with the cotyledons above ground. It is
a marked characteristic of the Dicotyledons that the cotyledons are
epigeic, and it is only in a relatively few families that they remain
underground, serving only as storage organs. Subterranean coty-
ledons, however, are known from trees, shrubs, and herbs, terrestrial
as well as aquatic, but the Nymphaeaceae is the only family in
which all the species, so far as known, germinate with the cotyledons
underground and inclosed within the seed. In the other families
subterranean cotyledons are characteristic of some certain groups,
for instance, Vicieae, or genera: Phryma, Sanguinaria, Caulo-
phyllum, Panax, Melittis, Collinsonia, Quercus, Castanea, Aesculus,
Sassafras, Citrus, Aegle, Mangifera, Persea, Prunus, etc. While
in some genera the majority of the species germinate with epigeic
cotyledons, some exceptions occur, for instance in Amemone,
Oxalis, Clematis, Aristolochia, Phaseolus, Rhamnus, etc., where some
few species have the cotyledons constantly subterranean.

Characteristic of the seedlings with hypogeic cotyledons is the
generally strong development of the primary root. In the Nym-
phaeaceae, Nuphar, Nymphaea, and Victoria, however, the primary

1921] HOLM—CARYA AND JUGLANS 381

root increases but little in length during the first stages of germina-
tion, its function becoming performed by a whorl of very long root
hairs developing from the base
of the root as soon as the seed
germinates. In Nelumbium, on
the other hand, the root remains
rudimentary, and no whorl of
hairs becomes formed.‘

The structure of the seedling
of Juglans nigra (text fig. 1)
agrees with that of J. regia L.
as described by ScHacut’ and
Kress. The primary root (R)
is stout and quite long, but it is
not fusiform as inCarya. There
is no hypocotyl, and the coty-
ledons remain underground, in-
closed, or partly so, by the
bony endocarp. They are short
petioled, auriculate at base, two-
lobed, and the lobes bifid. The
petioles form a sheath (S)
around the plumule, which dur- d
ing the first season develops into
a glabrous short shoot. The
first four or five leaves are very
small, scalelike, and entire; the

6 Porreau, Mémoire sur l’embryon
des Graminées, des Cypéracées, et du
Nelumbo. Ann. Mus. Hist. Nat. 13:397-
1809.

MrrseEL, B., Observations anatomi-
ques et phystoloutiies sur le Nelumbo
bid. -p. 474.

nucifera,
7 Scuacut, H., Beitrige zur Anatomie |
| Physiologie le Gewiichse. p. 105. 6

Fic. 1.—Young seedling of J. nigra,

en G., Beitriige zur Morphologie showing primary root (R), sheath formed

und Biologie der Keimung. Untersuch. by cotyledons a and aerial shoot; two-
Bot. Inst. Tiibingen 1:556. 1881-1885. atural size

382 BOTANICAL GAZETTE [DECEMBER

succeeding are small, odd-pinnate, with three to seven leaflets.
Buds are present in the axils of all the leaves, including the
cotyledons; and in specimens which were injured at the apex,
several of these buds had grown out into erect shoots (fig. 1).

In Carya alba and C. glabra (Mill.) Spach the seedlings agree
with those of Juglans, but the root is fusiform. Moreover, the first
two or three leaves succeeding the scalelike are unifoliate to tri-
foliolate, with the terminal leaflet very large, roundish, and far
surpassing the lateral in size.

Root

The primary root of the seedling is stout and fleshy at the base,
owing to the large development of the parenchymatic tissues, pri-
mary as well as secondary. The successive development of the
various tissues may readily be seen in the same root, when examined
from base to apex. In beginning with the basal swollen portion,
the structure is as follows. Only some few, more or less broken
strata of the primary cortex and part of the endodermis still adhere
to the root, which is now covered by four or five layers of thin-
walled cork of pericambial origin. Inside the cork is a broad
parenchyma, the secondary cortex, rich in starch, and interrupted
by two concentric bands of isolated strands of stereome. The
stele shows an almost continuous zone of leptome and cambium,
while the hadrome corresponds with eight distinct mestome strands.
On the inner flank of the interfascicular cambium some few young
vessels are visible; moreover, there are four rays of narrow proto-
hadrome vessels readily distinguishable from the secondary by
their narrow lumen. The central portion of the stele is occupied
by a broad starch-bearing pith. In comparing this structure with
that of the younger apical part of the same root, the following
distinctions are noticeable. There is a glabrous epidermis, desti-
tute of root hairs, and the primary cortex is a broad parenchyma
without starch or crystals. Inside the endodermis is a pericambium
of a single layer, in which tangential divisions have commenced,
indicating the beginning formation of the cork (fig. 15, Co). Bor-
dering on the pericambium is a zone of about eight layers of thin-
walled parenchyma (fig. 15, C*), representing a secondary cortex.

1921] HOLM—CARYA AND JUGLANS 383

This tissue does not contain starch or crystals, but is interrupted,
here and there, by narrow strands of secondary leptome, covered
by young thin-walled stereome (fig. 16, St), in two concentric
bands. Then follows a continuous zone of cambium connecting
the four collateral mestome strands, and from which (the cambium)
some few young, wide, porous vessels have become developed.
Beside this secondary mestome the protohadrome vessels are very
distinct, forming four short narrow rays of annular and spiral
vessels,

The very commencement of the formation of these secondary
tissues, the cortex and the collateral mestome strands, but not the
cork, can only be traced at the youngest, the apical, portion of this
toot. The earliest appearance of the secondary formations depends
upon a double meristem arising along the inner flank of the primary
leptome, and from which secondary leptome and hadrome become

ormed. Outside the protohadrome the pericambium then com-
mences to divide, forming another meristem, which in Juglans gives
tise first to parenchyma, a secondary cortex, and a little later to
a peripheral cork. Regarding the stereome, so amply represented in
the secondary cortex, this tissue is totally absent from the primary
structure of this root. It arises outside the leptome (fig. 16, S?),
and is formed by the secondary cortex, soon developing to distinct
Separate strands, arranged in one or several more or less concentric
ands.

In old, thick, lateral roots the epidermis and the primary cortex
are replaced by many layers of thin-walled, homogeneous cork, which
surround a broad zone of compact thin-walled parenchyma (second-
ary cortex), the cells of which contain much starch and numerous
aggregated crystals of calcium oxalate. In this secondary cortex
are five or six concentric bands of isolated stereome strands (fig. 17,
St). Viewed in longitudinal sections these stereome strands
traverse the parenchyma in wavy, not parallel lines. The stele
contains a peripheral zone of almost continuous leptome, also
several strata of cambium, beside a dense mass of hadrome, in
which wide porous tracheids with bordered pits are quite con-
spicuous. Thick-walled libriform, and thin-walled parenchyma
with starch represent also a large part of the stele. The medullary

384 BOTANICAL GAZETTE [DECEMBER

rays (fig. 17, PR) are narrow, mostly of a single row of cells, com-
pressed radially, and filled with starch. The protohadrome vessels
are readily seen in the center of the root, surrounded by strata of
thick-walled conjunctive tissue; no pith is developed.

STEM

The young shoot, examined in the early spring, is densely
covered with hairs, especially glandular. Unicellular, pointed
hairs are also common, and these occur in clusters of from two
to fifteen, or even more. The cuticle is thick, smooth, and the
epidermis is thick-walled. During the fall the epidermis is replaced
by a hypodermal cork of heterogeneous structure, thin-walled
strata alternating with thick-walled. This cork is developed from
the hypodermal stratum of a collenchyma. Inside the collenchyma
is a broad, compact, thin-walled parenchyma, filled with starch
and large aggregated crystals. Two concentric bands of stereome
are developed in the inner part of the cortex. There is no endo-
dermis, and the stele shows a continabis zone of leptome, inter-
spersed with cells containing singl iccrystals. The cambium
is well represented, and in the hadrome the porous vessels are
remarkably thick-walled. Cells containing single crystals occur
also in the hadrome. The medullary rays are narrow, mostly of a
single row of cells, containing starch. There is a relatively thick-
walled pith, porous, filled with starch and aggregated crystals, and
becoming soon septate as in Juglans regia and Pterocarya, as
mentioned by SOLEREDER. A corresponding structure is exhibited
by the old thick branches, but in these the stereome occurs in a
larger number of concentric bands, twelve or even more. The pith
also is here divided by transverse septa.

Finally may be mentioned that the internodes of the young
seedling are perfectly glabrous; and a cork is developed from the
hypodermal layer of the cortex, or from the stratum inside this;
both cases may be observed in the same section. There is no
collenchyma in these internodes during the first season, and the
cortex is thin-walled throughout, destitute of starch and crystals.
Inside the barely distinguishable endodermis are four or five layers
of thick-walled stereome, forming arches, more or less continuous

1921] HOLM—CARYA AND JUGLANS 385

as a closed sheath. Bordering on the stereome is a broad zone of
thin-walled parenchyma, with narrow isolated strands of leptome.
The cambium forms a closed ring, and the hadrome is in deep rays
with much thick-walled libriform. The pith is homogeneous,
thin-walled, filled with starch, but solid, not septate as in the shoots
of the mature tree.
LEAF

When unfolding, the leaves are very hairy, especially on the
dorsal face, and the hairs are of the types that occur on the young
shoots. The stomata are confined to the dorsal face, and lack
subsidiary cells. They represent two sizes, both of which are
equally common. Viewed in superficial sections the lateral walls
of epidermis are straight om both faces of the leaf blade. With
regard to the distribution of the various hairs, the pointed, fascicu-
late, abound beneath the veins, and are absent from the ventral
face; the glandular are common on both faces; but the largest
type, sessile with a large head, are confined to above and below
the mesophyll. The mesophyll consists of a compact palisade
tissue of a single stratum, or sometimes two strata (fig. 18, P),
covering a very open pneumatic tissue with numerous large cells
containing aggregated crystals, especially close to the epidermis.

The midrib is supported by several hypodermal layers of
collenchyma on both faces, and is furthermore surrounded by a
water-storage tissue. There is no endodermis, but a closed sheath
of thick-walled stereome’ in several strata surrounding the steloid
midvein, which is composed of an obtusely triangular band (in
cross-sections) of collateral mestome strands inclosing a central
parenchyma, a pith. In these mestome strands the hadrome
faces the pith, while the leptome turns toward the periphery, even
in the ventral part of the stele. Characteristic of the hadrome is
the abundance of thin-walled parenchyma in continuation with the
vessels. The lateral veins contain only single mestome strands
which are supported by stereome extending to the ventral and
dorsal epidermis, broken on the sides by thin-walled cells of a
parenchyma sheath.

Between the leaflets the rhachilla is hemicylindric (in cross-
sections), very hairy, with long stalked glandular hairs. Several

386 BOTANICAL GAZETTE [DECEMBER

hypodermal and continuous layers of collenchyma surround a broad
thin-walled cortex, rich in chlorophyll, and with some aggregated
crystals. No endodermis is developed, but a closed sheath of
stereome surrounds a stele of collateral mestome strands as in the
midrib of the blade. The pith is solid, not divided into septa.

Examined just below the basal pair of leaflets, the petiole is
hairy like the rhachilla, and shows the same structure, except that
there are two thin collateral mestome strands located in the cortex,
thus outside the stele, and in these the leptome is covered by a
few layers of stereome; the pith is solid.

COTYLEDONS

Although completely subterranean, the epidermis of the cotyle-
dons shows stomata, but relatively only a few, on both faces of the
thick fleshy blade. The lateral cell walls are straight on both faces,
and the lumen is about the same, or slightly wider on the ventral
face. The mesophyll lacks palisade cells, and is composed of a
large, thin-walled, compact parenchyma of roundish cells. All the
mestome strands are single, collateral, surrounded by parenchyma
sheaths, and are imbedded in the mesophyll. The leptome is
generally much better represented than the hadrome, and no
mechanical tissues are developed in these leaves.

Juglans cinerea shows the same structure as J. nigra, with the
only exception that the pericycle in the stem represents an almost
closed sheath interspersed with large, thick-walled, and porous
sclereids. The pith is discoid, and the diaphragms contain many
aggregated crystals. The pointed hairs of the leaf are more abun-
dant than in J. nigra, and occur mostly in clusters of two to eight on
the dorsal face of the blade.

Characteristic of Juglans and Carya is thus the ample represen-
tation of mechanical tissues, as collenchyma, stereome, and libri-
form. Of these the collenchyma occurs in the stem, the periphery
of the cortex proper, and in the leaves as hypodermal strata on
both faces of the midrib. The stereome occurs as a secondary
tissue in the cortex of the root and stem, as well as pericyclic arches
or, sometimes, forming a closed sheath, interspersed with sclereids

1921] HOLM—CARYA AND JUGLANS 387

in J. cinerea; it occurs also in the leaves forming a sheath around
the midrib. Thick-walled libriform is noticeable already in the
apical internodes of the seedling, and in branches of the mature
tree the hadrome is divided by broad tangential bands of this
tissue. In old roots of /uglans the libriform is much in evidence.

With respect to the distribution of the calcium-oxalate as single
or aggregated crystals, SOLEREDER (Anatomie Dicot.) calls atten-
tion to the very varied occurrence of these types of crystals. In
Juglans nigra aggregated crystals were observed in the inner part
of the cortex and pith of the stem, as well as in the pneumatic
tissue of the leaf. On the other hand, single crystals were noticed
in the leptome and hadrome of the stem. In Carya alba aggregated
crystals were observed in the cortex and leptome of the stem, as
well as in the palisade tissue of the leaf, and in the pith of the
steloid midrib. Single crystals, on the other hand, were found in
the collenchyma of the stem, as well as in the pneumatic tissue of
the leaf and in the pith of the steloid midrib; thus both types of
crystals occur in the pith of the midrib.

Of greater interest, however, is the singular structure of the
pith in Juglans and Pterocarya. The history of this structure, the
discoid pith, dates back to Grew,? who discovered it in Juglans.
By MirBeEL” it was mentioned as peculiar to Phytolacca, Nyssa,
and Juglans. Dr CANDOLLE™ found a discoid pith in Jasminum
officinale. MorreEN,” in describing discoid piths of plants, enumer-
ates several other plants, for instance, Begonia argyrostigma, while
this writer found the pith to be solid in B. undulata, B. semperflorens,
and B. papillosa. According to SOLEREDER the discoid pith is
characteristic of two herbs, Diplotaxis and Pedalium, and among
woody plants he enumerates Wormia (Dilleniaceae), Fouguiera
(Tamariscineae), Prinsepia (Chrysobalanaceae), Aucuba, Halesia,
Paulownia, Daphniphyllum (Daphniphyllaceae), as well as the

9 GREW, N., Anatome plantarum. I. ro. fig. 4. 1682.

MirzeL, B., Elémens de Physiologie végétale et de Botanique. 1:112. 1815.

™ Dre CaNDOLLE, A. P., Organographie. 1:167. 1827.

Morren, C., On the discoid piths of plants. Ann. Nat. Hist. London. 4:73.
1839-1840.

388 BOTANICAL GAZETTE - [DECEMBER

genera mentioned in the preceding. By Foxwortuy™ a general
discussion of discoid pith has been presented. Finallyby the writer™
the structure of the pith in Phytolacca decandra L. has been described
and figured

While the discoid pith is thus characteristic of the species of
certain genera, it has been shown that in Begonia, Forsythia,
Jasminum, and Phytolacca this structure occurs only in certain
species. Juglans and Pterocarya are definitely separated from
the other genera by the possession of a discoid pith. It is a very
interesting structure, which, however, must not be confounded
with cases where the pith is solid, and divided by horizontal dia-
phragms of sclerotic cells, so characteristic of many Magnoliaceae,
Anonaceae, Ternstroemiaceae, and Convolvulaceae.

Ciinton, Mp.

EXPLANATION OF PLATES XV, XVI
PLATE XV
Carya alba

Figs. 2, 3, 4, 7, 8, 10, 11, 13, and 14 are enlarged.

Fic. 1.—Staminate flower: St, stem; L, bract; P, prophylla; 5S, stamens.

Fic. 2.—Involucre of staminate flower, seen from outside.

Fic. 3.—Staminate flower, side view.

Fic. 4.—Stamen

Fic. 5.—Pistillate flower: PL, perianth leaves; other letters as preceding.

Fic. 6.—Pistillate flower with single perianth leaf.

Fic. 7.—Pistillate flower, side view; PS, petiole.

Fic. 8.—Pistillate flower, seen from above.

Fic. 9.—Cross-section of inner part of primary root of seedling in second
year: St, stereome strands outside secondary Jeptome (L); Camb, cambium;
H, hadrome; PR, parenchymatic ray; P, pith; x 320.

Juglans nigra

Fic. 10.—Staminate flower, seen from outside; stamens removed.

Fic. 11.—Two stamens, side and front view.

Fic. 12.—Branch with pistillate flowers; natural size

Fic. 13.—Longitudinal section of pistillate flower; P+, perianth leaves.

Fic. 14.—Cross-section of stigma.

3 Foxwortuy, E. W., Discoid pith in woody plants. Proc. Indiana Acad. Sci.
P. I9I. 1903.

™ Horm, THEO., Medicinal plants of North America. 9. Phytolacca decandra
L. Merck’s Report. p. 312. 1907

BOTANICAL GAZETTE, LXXII, PLATE XV

=: - St. Ss

i
ie
ais

SY
Ak

HOLM on CARYA and JUGLANS

PLATE XVI

BOTANICAL GAZETTE, LXXII

HOLM on CARYA and JUGLANS

1925] HOLM—CARYA AND JUGLANS 389

PLATE XVI
Juglans nigra

Fic. 15.—Cross-section of primary root of young seedling a month old:
C, inner part of primary cortex; End, endodermis; Co, pericambial cork; Ct,
oa ona part of secondary cortex; X 320

Fic. 16.—Inner part of same root (i. 15): C+, secondary cortex with
strands of stereome (Si); L, leptome; Camb, daxcbiiti: P, outermost layer of
pith; x32

Fic. 17. te cross-sections of old lateral root; PR, parenchymatic ray;
X 320.

Fic. 18.—Cross-section of leaf: Ep, ventral, Ep+, dorsal epidermis; P,
palisade tissue; P+, pneumatic tissue; 320.

PHYLOGENETIC POSITION OF THE BACTERIA*
HitpA HempL HELLER

The subject of the phylogenetic position of the bacteria has
been approached by many students. Early workers came to no
more diverse conclusions than do modern ones. Some investigators,
for example NAGELI (24) and GérscuiicH (14), have placed the
bacteria with the fungi, while Conn (9), Micua (22), and SACHS
(26) placed them with the algae. The early workers who assigned
the bacteria to the fungi did so because both fungi and bacteria
lack chlorophyll, and may thus be regarded as similarly degener-
ate algae, and because there are genera such as Corynebacterium,
Actinomyces, Streptothrix, and Oidium, that may well be regarded
as transitional forms. Classifiers of the fungi have not sufficiently
emphasized the fact that in a group where chlorophyll is absent
there is no compelling reason for presuming that the simpler forms,
the bacteria, were descended from the higher ones, as the workers
thought who considered them as directly descended from the algae.
Even De Bary (1), although he uses NAGELI’s name “Schizomy-
cetes”’ (fission fungi) for the bacteria, insists that they are not
fungi, nor closely related to or descended from fungi.

The reason for classing the bacteria as a subordinate group of
the algae has usually been the exceedingly close morphological
resemblance of the higher bacteria to the blue-green algae (Cyano-
phyceae or Myxophyceae). Coun was the first to emphasize the
relationship between these groups. The Cyanophyceae were long
thought to be the most simple autotrophic forms. More modern
systematists have separated the blue-green algae from those with -
sexual reproduction, and have united them with the bacteria.
Thus ENGLER (12), in his second phylum Schizophyta, included
only the two classes Schizomycetes and Schizophyceae; WARMING
(28) made a similar division of his class Schizophyta; while
BEssEY (3) in his phylum Myxophyceae, class Archiplastideae

*From the George Williams Hooper — for Medical Research, Univer-
sity of California Medical School, San Francis
Botanical Gazette, vol. 72} [390

1921] HELLER—BACTERIA 391

(blue-green algae without nuclear membrane), placed the Bacte-
riales as an order coordinate with two orders of the blue-green
algae. Birscuit (6) and Kies (19) emphasized the common
characters of the bacteria and the protozoa.

Today the question is apparently no nearer a solution than it
was forty yearsago. The various views are based on the considera-
tion of different life manifestations. Close relationship between
bacteria and protozoa, however, is no longer emphasized. The
principal views held today are three: (1) that the bacteria are
members of the group of fungi, (2) that they are derived from or
closely related to the Cyanophyceae, and (3) that they are the
primitive forms from which fungi and algae are derived. The first
two opinions are held by morphologists. Those who have regarded
the manner of division and sporulation, the external characters of
the organism so to speak, and those who hold that bacteria possess
a small oval or round nucleus, have allied the bacteria with the
fungi. Others who have studied their nuclear structure have allied
them with the Cyanophyceae. Chemists and general students of
evolution have recently considered them as ancestors of the other «
groups.

The morphological field has been reviewed carefully by MEYER
(21), who holds that the closest affinities of the bacteria are with
the fungi. The bacterial nucleus, according to his conception, is
similar to the nucleus of the fungi. SWELLENGREBEL (27), GARD-
NER (13), and Dopett (11) have observed structures, which they
believe to be nuclei, that have marked resemblance to the chromo-
phyll portion of the central bodies of the Cyanophyceae. GUILLIER-
MOND (15) and a number of other workers hold the bacterial
nucleus to be ‘‘chromidial”’ or finely distributed in the cytoplasm.
Dose tt finds structures resembling all these types, which he holds
to. be nuclei, and he believes the bacteria to be related most closely
to the Cyanophyceae. West (29) described a blue-green alga,
Myxobactron, which shows no differentiation of its protoplasm.
PARAVICINI (25) has recently described minute compact structures
that he believes to be nuclei.

JENSEN (18) rearranged the bacteria on a chemical basis, and
defined their relation to the algae, fungi, and protozoa, presuming

392 BOTANICAL GAZETTE [DECEMBER

that the earth was dark when life began, and that chlorophyll-free °
bacteria, probably those capable of oxidizing methane, were the
earliest forms of life with which we are familiar today. JENSEN
derived the blue-green algae from the sulphur bacteria, the fungi
from the oxidizing bacteria by way of the Actinomycetes, and the
‘ higher bacteria from the earliest nitrogen-reducing organisms.
KLIGLER (20) was also of the opinion that bacteria may well have
been the earliest forms of life, and he placed the methane-oxidizing
type at the base of his tree. BREED, ConN, and Baker (4) pointed
out that there is no proof that the world was dark when life began;
that in case it was light the ancestors of the blue-green algae or of
the phototrophic pigment bacteria, which use sunlight to metabolize
organic substances, may have been the most primitive forms; or
that the most primitive form may be entirely unknown tous. Thus
we see that because of the discovery of the existence of autotrophic
bacteria the old question of the origin of the bacterial group is
, again open.
_ When the synthesis of inorganic substances into organic material
‘was thought to be possible only by the aid of chlorophyll, the
natural trend of evolutionary reasoning led to the derivation of
other forms of life from simple chlorophyll-containing ones. Bacte-
Tia apparently are simpler than the most simple chlorophyll-bearing
algae. They were therefore thought to be degenerate. Workers
who saw in them affinities with the chlorophyll-free fungi were
not careful to state what their relationship with the fungi really
might have been. The reader is usually left with the impression
that they are in an intermediate position or related to the higher
fungi. Meyer, who excluded the Thiobacteria, Chlamydobacteria,
and Myxobacteria from his Eubacteria or bacteria proper, placed his
group as the second class of the Eumycetes next to the Phycomy-
cetes or algal fungi. CLaypore (7) considered both bacteria and
fungi to be derived from the leptothrix-tuberculosis group.
A rather suprising paper has recently appeared by BERGSTRAND
(2), who has observed the budding and branching of Coryne-
bacterium and other forms, and believes that the bacteria are closely
related to the fungi. Budding and binary fission are not so different
in their nature that they should be considered very important

1921] HELLER~BACTERIA - ! 393

characters. One genus of yeasts, the Schizosaccharomyces, divide
as do the bacteria. Apparently typhoid bacilli may either bud or
divide by fission Hort (16). Upon this one character of budding,
BERGSTRAND lays so much emphasis that he refuses to consider
other characters, also morphological, which show similarity between
the bacteria and other forms: ‘“‘To discuss further the eventual
relationship of Cyanophyceae to bacteria does not seem necessary,
because any such theory would appear false at the moment that it
became clear that bacteria are more closely related to fungi, as
I shall show.”’ It must be noted that, like MEvER, BERGSTRAND
excludes from his bacterial group the higher bacteria which do not
resemble the fungi as much as they do the algae. One would be
equally justified in naming as bacteria all the chlorophyll-free rods
except the branching and budding ones. BERGSTRAND defines the
bacteria as Fungi Imperfecti. The Fungi Imperfecti are an entirely
artificial group comprising fungi that have not developed sexual
characters, those that have lost such characters, and those that
have not been studied sufficiently to determine their true relation-
ships. BERGSTRAND concludes that bacteria are to be regarded as
Fungi Imperfecti that have developed through the reduction of
higher forms, and not as lowly primordial organisms to be placed
at the very beginning of the organic world. An example of his
logic is as follows: ‘“‘Of course if one regards bacteria as Fungi
Imperfecti one cannot accept the theory that the chromatin is
spread diffusely in the cell body, because this assumes it would
seem a much lower developmental stage.”

It is not the intention of this paper to criticize workers for
connecting bacteria with fungi because of morphologic relationships
between the two groups. BERGSTRAND’s observations serve to
strengthen the tie between the fungi and the bacteria, but the
lightness with which he proposes the degeneracy of the latter forms
from the former is a novel process to comparative biological reason-
ing. The trend of evolution is rarely in the direction of degeneracy.
Degeneracy occurs as a.consequence of a parasitic habit or because
of abundant food supply. It is usually accompanied by vestigial
traces of a former complexity. The characters which the bacteria
and fungi have in common are not manifestly vestigial in the

394 BOTANICAL GAZETTE [DECEMBER

bacteria. The supposed loss of sexual characters among the fungi
has been attributed to their change from water forms to air forms,
but bacteria are not air forms. The theory of the degeneration of
the bacteria from the algae was a very peculiar one, imposed by
ignorance of certain primitive bacteria. It is now known that
bacteria exist which are autotrophic and can secure growth energy
from inorganic carbon, so that their lack of chlorophyll is no longer
a reason for considering them degenerated from the chlorophyll-
containing forms. The existence of autotrophic fungi, to my
knowledge, has never been demonstrated.

There is a simple group, therefore, the members of which are
autotrophic; and two diverse complex groups, one of which (the
fungi) is not autotrophic and may not be homogeneous. Both o
these complex groups show marked resemblances to the simple one.
JENSEN’s scheme, which derives both of them from the simple one,
is not to be lightly thrown aside. It coincides too well with the
general scheme of evolution. We may, if we wish, consider the
question entirely open, but nomenclature and classification should
be so formulated that they do not deliberately mislead the amateur
on the subject of these relationships. Formerly the tendency in
botanical classification was to make a treelike structure, throwing
groups together that had but superficial resemblances, but classifiers
today are more prone to refuse to indicate relationships where
descent is not fairly certain, and to group the plants in phyla like
the zoological phyla, whose connections may or may not be under-
stood.

The bacteria, fungi, and blue-green algae, therefore, may be all
in one phylum, or may be placed in three separate phyla, but to
place the bacteria with either fungi or Cyanophyceae is incon-
sistent, because it leaves out of consideration the third group which
may be equally related to the bacteria. Probably the trend of
classification would favor the separation of these groups into three
separate phyla, for to place the fungi and Cyanophyceae together
is rather stretching the limits of the botanist’s conception of a
phylum. Moreover, in view of the existing divergent opinions, a
classification that does not commit one on the subject of these
relationships is preferable. A name for the phylum that is to

1921] HELLER—BACTERIA 395

contain the bacteria only should not indicate for them a subordinate
position in another group as does the name “Schizomycetes,”
proposed by NAcELI (23) in 1857 for a mongrel group which
contained bacteria, sporozoa, and oscillaria, a group whose affinities
he hesitated to suggest. The connotation of this term has always
been “fission fungi,” and its German form “Spaltpilze” has been
widely used. And yet BucHANAN (5) finds it entirely appropriate
and valid and proceeds to place his Schizomycetes with the Cyano-
phyceae. Article 51, division 4, of the Vienna rules (17) considers
the name Schizomycetes as invalid. ‘Everyone should refuse to
admit a name... . when the group which it designates embraces
elements altogether incoherent, or when it becomes a permanent
source of confusion and error.”

We should choose for the bacterial phylum a name that will
immediately be understood by the non-professional worker.
Names like Phytozoidia Perty of course are objectionable. Vibrio
Ehrenberg probably included certain infusoria as well as bacteria.
Vibrionia Cohn did not include forms later studied by that author.
Bacteria Cohn (8) probably included all the forms that we today
call bacteria except Beggiatoa, and it did not include members of
other groups. As the Committee. of the Society of American
Bacteriologists (10) places 1880 as the date at which considerations
of priority are to commence, we are free to choose from among these
names. Bacteria implies no relationship to other groups. It is
otherwise highly suitable because it is understood by laymen and
is short and euphonious. The following was CoHNn’s conception
of the group: ‘Die Bacterien sind chlorophyllose Zellen von
kugeliger, oblonger oder cylindrischer, mitunter gedrehter oder
gekriimmter Gestalt, welche ausschliesslich durch Querteilung sich
vermehren, und entweder isoliert oder in Zellfamilien vegetieren.”

In consideration of the fact that no relationship of the bacteria
to other groups has been generally accepted the following phylum
is proposed:

Bacteria (nov. phyl.).—Simple one-celled plants that multiply
typically by binary fission and occasionally by budding. They
show no form of sexual multiplication. They rarely contain
cellulose and do not contain chlorophyll or phycocyanin.

UNIVERSITY OF CALIFORNIA

396 BOTANICAL GAZETTE [DECEMBER

LITERATURE CITED
1. DE Bary, A., Compara’ gy and eae of the fungi, myceto-
zoa, and bacteria. ‘eagad they se Oxford, 18
2. rage as H., The nature of bacteria. ee Infec. Diseases 27:

I-22.
3. BESSEY, C. on The plant phyla. a
4. BREED, R. S., Cox, H. J.,and Baker, J. C., Comments on the evolution

and classification of the bacteria. ees Bacteriol. 3°445-459. I91
5. BucHANAN, R. E., Studies in the SN aeayeppoe and classification ot the
npr “ir. Jo ur. Bacteriol. 2: eT IQI
6. BUTSCHLI, my Quoted from A. Mey
7. CLAYPOLE, E, J., On the igaeatna of the streptothrices, particularly
in their relation to bacteria. Jour. Exper. Med.
8. Conn, F., Untersuchungen iiber Bakterien. Biologie der Pilanzen 12127;
1872; quoted from Micuta, System “itd Bakterien 1:17. 1897.
i , Unte erage sare iiber Bakteri II. Beitrige zur Biologie der
Pflanzen 1: 1875; quoted from “yang System der Bakterien 1:19. 1897
10. Final Rep. Com oe Amer. Bacteriologists on anlar omnes: ane
classification of Geiteetil types, the families and genera of the bacteria.
Jour. Bacteriol. 5:191. 1920; prelim. Rep. ibid. oe. 1917.
tt. Dower, C.-C, Sg amy to the cytology of the bacteria. Quart.
Jour. Micr. Sci. N.S. 56: 395-506. pls. 4. IO1T.
12. ENGLER, A., Syllabus der Pflanzenfamilien. 190
13. a ot ; N. L., Cytological studies in caso ices Univ. Calif.
14. Corned ioe argpestooidl of seem s peepee 1896.
15. GuILuERMonn, A., Quoted by A.
16. ee E. = , The life history of sockets " Brit, Med. Jour. 1:571-575-
Ss
17. Trans. tae Bot. Congress, Vienna,
18. JENSEN, ORLA, Die Hauptlinien des ratichen Bakteriensystems. Cen-
tralbl. ‘Bakteriol. Abt. I. a3: ib yey
19. Kies, G., Quoted by A. MEYE
20. KLIGLER Cs J., The evolution ini nae eas a of the great groups of
bacteria. Jour. Bacteriol. 2: 165-17
21. MEYER, A., Die Zelle der ot tia Tak, 10% 2.
22. Micuta, W., In Warmino’s Systematic Botany, Engl. Transl. p. 26. 1904.
23. NAGELI, O., ‘Amtlicher sane iiber die 33 Versammlung Deutscher Natur-
forscher und Aertzte zu Bon Nn, p. 133, 1857 (1859), quoted f from MIGcULA,
System der Bakterien 1:9. 1897.
24. ———, Die niederen Pilze in ihren Beziehungen zu den Infektionskrank-
heiten. "1877; quoted from MAancrtn, Bacteria. 1884.
25. PARAVICINI, E., Zur Frage des Zellkernes der Bakterien, Centralbl.
Bakt. Abt. II. 48: 337-340. 1917-19
26. Sacus, J., Quoted from STERNBERG, radibedk of bacteriology. 1
-27. SWELLENGREBEL, N. H., Unt tersuchungen iiber die pies ae mini
Fadenbakterien. Arch. Hyg. 70:380-403. pls. 2. 1900. .
28. WARMING, E., Systematic botany. Engl. Transl. Pp. 22. 1904
29. WEsT, W., Preih en ter algae of the Percy Sladden Memorial al Expedit jon in
South West Africa. Ann. So. African Mus. 9: 1912; quoted from WEST,
Algae. tend

ODONTOPTERIS GENUINA IN RHODE ISLAND
Eva M. Rounp
(WITH FIVE FIGURES)

One of the most characteristic and common fossils of Rhode
Island is Odontopteris genuina Grand’Eury. These plants appar-
ently grew to great size around the coal swamps of the Narra-
gansett Basin during the Carboniferous, somewhat like the tree
ferns of the tropical forests of the present day (fig. 1). The
fronds appear to have been bifurcate, the angle formed by the
branches being about 90° (fig. 2). The rachis is striated and
clothed with short pinnae, the latter having enlarged pinnules at
their tips and being more separated than those of the expanded
parts of the frond. The pinnae vary considerably, sometimes being
short or at other times attaining a length of over 15cm. The
pinnules often vary in shape on the same specimen, some being
falcate and acute, while others are oval and rounded at their
apices. The acute type of O. genuina is very common in the state,
and may have come about as a result of the conditions under which
the fossils were originally imbedded. The pinnules appear to have
been firm in texture and convex or “bombe”’ in shape. If these
shapes were squarely imbedded they would appear oval (fig. 3a)
when fossilized, while more pointed effects would result from pres-
ervation at a slight angle (fig. 3b; fig. 4a, b), and long, narrow
effects from still greater angles (fig. 5a). While these forms have
pinnules 3-8mm. broad by 10-16 mm. long, the illustrations
from Pawtucket show much larger sizes and resemble those figured
by ZEILLER' from Commentry, France. The Pawtucket specimens
do not appear to have been as firm and thick as the smaller Rhode
Island types, and the borders are inclined to be less even. The
pinnules also were evidently flat rather than convex in shape and
somewhat cyclopterid in appearance (fig. 3c, d; fig. 56).

* ZEILLER, C. R., Etudes sur le Terrain Houiller de Commentry. #/. 24. 1888.
397] [Botanical Gazette, vol. 72

398 BOTANICAL GAZETTE [DECEMBER

It appears that O. genuina has frequently been listed among
Rhode Island fossils under the name O. brardii Brgt., presumably

Fic. 1.—Odontopteris genuina: tip of frond (distorted); reduced }.

owing to the numerous examples of falcate forms in evidence.
A careful study of the veining upon good material, however,

1921] ROUND—ODONTOPTERIS

399
reveals a much more complex system than that of O. brardii?
In general the O. genuina has a thin medial nerve, distinct almost
to the apex, while the lateral veins spread at very acute angles

ttf ) Wi
wie t IN) ORSANANG
NS IN
Lear ir ais
Z/IS\ ‘S ON WS
ZE Ziff (d\n \ \ f iS
(ZZ AS WN
AN
i N\A
Lhe a> \ \
\l
Qa,

Fic. 2.—Odontopteris genuina: mode of branching; reduced 3.

and fork in passing to the border one to four times, the lowest
or outermost only coming from the rachis.

Typical O. brardii,
on the other hand, is described as having veins all of which come

? BRONGNIART, A., Histoire des végétaux fossiles. pis. 75, 76. 1828.

400 BOTANICAL GAZETTE [DECEMBER

Fic. 3.—Odontopteris genuina: slightly reduced.

; b,

1Ze

S genuina: a, natural s

ery

ny
MS
a
gy
ah
AY
So
wy
at
Qo
Q
T
a
q
=
S
Re

Fic. 4.—Odontopt

402 BOTANICAL GAZETTE [DECEMBER

from the rachis, a condition which the writer has never observed
in Rhode Island specimens.

Fic. 5.—Odontopteris genuina: natural size.

Odontopteris genuina has been found in eight localities in the
state, namely, Portsmouth, Boyden Heights, The Tunnel, Provi-

1921] ROUND—ODONTOPTERIS 403

dence, Pawtucket, Arlington, Cranston, and Warwick. These
rocks are now in the collection of the geological department of Brown
University. As they never appear waterworn it may be inferred
that these plants fringed the coal: marshes of the Narragansett
Basin in the Carboniferous, and were buried and fossilized near
their places of growth. ‘Most of these fossiliferous materials are
preserved in fine grained black shale. The specimen from Boyden
Heights, however, is of sandstone, a material not generally fossil-
iferous in the state except as the matrix of coarse forms like Cala-
mites (fig. 3a).

With such abundance of preserved material as is represented
by O. genuina in Rhode Island, it seems significant that no fruited
pinnae are in evidence. It has been proved by KipstTon,? however,
that many of the so-called fossil “ferns”? were really Pteridosperms
or Cycadofilicales. Many detached seeds are found in the rocks
of Rhode Island, proof that the ancestors of modern flowering
plants were denisons of the coal forests of the state, among which
it seems probable that O. genuina may sometime be included.

3 Kipston, R., Les végétaux houillers recueillis dans le Hainaut belge. Mém.
Mus. Roy. Hist. Nat. Belg. 4:5. 1911.

BRIEFER ARTICLES

ROOT DEVELOPMENT OF WHEAT SEEDLINGS
(WITH ONE FIGURE)

In a study of the salt requirements of wheat in water cultures,
certain conditions under which wheat seedlings developed relatively
large root systems were noted. Wheat seedlings with shoots 8-10 cm.
high and roots 10-12 cm. long were set out according to the usual
method employed for solution culture experiments, in two quart Mason
jars filled with tap water from the laboratory. The cultures were
allowed to grow for six weeks at a temperature range of 22-32°C.
and without renewal of the tap water. At the end of this period the
tops of the cultures had grown about 12-16 cm. high (having gained
from 2 to 4cm.) and the root mass measured 70-80 cm. in length.
In some cultures, however, single roots had attained a length of over
roocm. So far as the total dry weight of these cultures was concerned,
it may be stated that about one-half was contained in the roots.

It was at first thought that the relatively low total salt concentra-
tion of the tap water was responsible for the results. The tap water
of the laboratory contained a total salt concentration whose osmotic
value was calculated to be approximately equal to o.1 atmosphere
pressure. To test this supposition as being the cause for the extraor-
dinary long root growth of the wheat seedlings, several different kinds
of complete nutrient solutions were prepared, each having a total salt
concentration giving an osmotic value equal to about o.1 atmosphere
pressure, and these were used as the culture media for wheat. These
dilute solutions, which contained all of the chemical constituents essen-
tial for plant growth, proved to be relatively poor media for the root
development of wheat aera nother set of tests, however, with
solutions of th Its and sa Pro] those of these dilute solu-
tions but of greater total ( here), proved to be very
good media for the root penis of wheat seedlings. These results
suggested that it might be the absence or the deficiency of an element
in the tap water that was responsible for the results. Tests were then
made using nutrient solutions of a total salt concentration equal to give
about o.5 atmosphere osmotic pressure, but modified so as to omit one
Botanical Gazette, vol. 2] [404

1921] BRIEFER ARTICLES 405

of the elements considered essential for normal plant growth. Wheat
seedlings with shoots 8-10 cm. high and roots 10-12 cm. long were

grown in solutions that lacked nitro-
gen had developed a root system similar
and equal in length to those obtained from
cultures grown in tap water. The tops of
the plants grown in the relatively nitrogen-
free solutions gained only a few centi-
meters in shoot length, but the root mass
had attained a length of 60-70 cm. for the
different cultures of the set. From these
results it was concluded that stimulation
of long root development of wheat seed-
lings grown in tap water was related to
the deficiency of nitrogen in that growth
~medium.

Two questions might be asked in refer-
ence to the results obtained: (1) Can plant
roots grow without nitrogen? (2) What
constitutes the best root development of a
wheat plant for its normal growth? As to
the first question, the tests did not prove
that the large root development obtained
from wheat seedlings grown in tap water
or in the prepared nitrogen-free solutions
was due to the total absence of nitrogen, or
that it would have been obtained in the
total absence of nitrogen. Obviously some
nitrogen was contained in the seedlings
when they were set in these media. Pre-
sumably less and less became available to MG.

r—Culture to iit
the growing roots as the plants grew older, grown in tap water for six
however, as the small supply originally in °
the seed had to suffice for more and more
tissue (chiefly roots) as the seedlings en-
larged. Whether the supply was ever exhausted in the growing region
of the roots is not known.

in good nutrient solution for
two weeks.

406 BOTANICAL GAZETTE [DECEMBER

An answer to the second question must also be given as a hypothesis.
The large root development of the wheat seedlings placed in tap water
did not result in the production of large wheat plants. The roots
grew at the expense of the tops. Obviously wheat shoots could not
have grown to any appreciable extent without roots, so between the
two limits thus indicated (no roots on the one hand, and one-half of the
total dry matter being roots on the other hand) must be found that
relation of root to top that will bring about the best growth of the wheat
plant.

Fig. 1 shows the relative root development of two different cultures,
with approximately similar top growth. One was grown in tap water
for six weeks and produced roots over 100 cm. long, the root mass being
about six times longer than the length of the tops. The other culture
was grown in a good nutrient solution for two weeks and produced
roots that were only a trifle longer than the length of the tops. Approxi-
mately this same ratio of length of root to that of top would have been
maintained if it had been grown six weeks or longer in this good nutrient
solution.—W. F. Gericke, Division of Soil Chemistry and Bacteriology,
University of California.

CURRENT LITERATURE

BOOK REVIEWS
Ecological plant geography

The name of WARMING always comes first to mind when one thinks of the
great names in modern ecology. In November 1g21 he passed his eightieth
milestone, receiving a portrait album together with the congratulations of his
coworkers in all lands. Ten years ago he retired from active service at the
University of Copenhagen, but these ten years have been full of important
researches, and his publications during this period have been numerous. One
of the most important of these publications is the third German edition of his

he firs

being essentially an unmodified translation by KNnostaucs of the original

without cooperation with WARMING. The English edition of 1909 was essenti-
ally a new book, with a very different grouping of the subject matter, in which

WarMING, although it follows the general features of the English edition. “The
most conspicuous changes are seen in the chapter that deals with formations
and associations, and here the author follows the recommendations of the
Brussels Congress of 1910. The book is also much larger than preceding
editions, and the references to the literature are brought to date, so far as
possible. But for the war, the book would have appeared much sooner than
it did. It was asked for by the publishers in 1912, and was ready in 1914.—
H. C. Cow es.
Principes de Biologie aes

Following his volume on L’Evolution des Plantes, published in 1918, the
second posthumous volume of BERNARD’s? lecture notes has been published
under the title Principes de Biologie vegetale. The first part deals with cellular
physiology of plants, with chapters on the principle of determinism, physical
conditions of nutrition, nutritive metabolism, carbon nutrition, nitrogen nutri-
tion, and the action of exterior agents upon the living cell. The second part of

*Warminc, Evc., and GraEBNER, P., Evc. Warmino’s Lehrbuch der dko-
logischen Sis cnc daahier dritte umgearbeitete Aufiage. pp. 762. Berlin:
Gebriider Borntraeger. 1918.

2 BERNARD, NOEL, Principes de Biologie vegetale. pp. xiit+212. figs. 18. Paris:
Felix Alcan Library. 1921.

407

408 . BOTANICAL GAZETTE [DECEMBER

the volume is entitled coordination, and contains chapters on Thallophytes
and Schizophytes, Myxomycetes and fungi, algae, lichens, and a final chapter
on immunity among plants. It is an elementary treatise, written in enter-
taining and lucid style. That the author has been dead ten years accounts
for the appearance of occasional remarks which do not quite reflect our latest
knowledge, as for instance, that “the formula for the constitution of chlorophyll
is not known.” Beginners, ela in botany or French, would find it a delight-
ful little eine Cc. A. Suu

MINOR NOTICES

Flora of Natal.—Brws,3 well known for his ecological study of the vege-
tation of Natal, has published a taxonomic account of the flora “‘for the purpose

lytical keys are remarkably simple, leading to the genera, but the species are
merely listed, with their ecological range and often with their local Zulu names.

he author states that “the flowering plants of Natal, as now <i,
belong to 148 families, and include go1 genera and 3786 species.””—J. M

Osmotic pressure.—The publication of a new edition of Pfeffer’s4 famous
work on osmotic pressure will be welcomed by students of plant physiology and
physical chemistry who have desired to own a copy of this classic work. No
changes have been made from the first edition, except that an introductory
appreciation of PFEFFER’s work by Czapex precedes the text.—C. A. SHULL.

NOTES FOR STUDENTS

Specificity of chromosomes and sex-determination.—For a final proof of
the réle of the individual chromosome we must look to the remarkable investi-
gations of Bripces.’ It was this author who furnished a direct demonstra-
tion of the chromosome theory of heredity, when he showed that irregular
distributions of the sex chromosomes of Drosophila were accompanied by
irregularities in the inheritance of known sex-linked factors. He now® pro-
vides a similar demonstration of the specificity of the autosomes, and at the

3 Bews, J. W., The flora of Natal and Zululand. pp. vi+248. Pietermaritzburg.

pa 15s. (Whelden and Wesley, 28 Essex St., Strand, London
PFEFFER, W., Osmotische Untersuchungen. pp. xiv-+236. figs. 5. Leipzig:

reece 1921

5 Bripces, C. 8B. Non-disjunction as proof of the chromosome theory of heredity.
Genetics 1:1-52. 1916

6
192r.

, Triploid intersexes in Drosophila melanogaster. Science 54:252-254.

1921] CURRENT LITERATURE 409

same time adds a very significant and far-reaching modification of present
ideas on sex determination.

An unexpected distribution in inheritance of known factors which are
located on the second and third chromosomes of Drosophila was explainable
on the assumption that the female parent of the cross was a triploid with
respect to these chromosomes. Cytological examination proved that this
was actually the case. This same group of flies also exhibited some remark-
able irregularities in their sex condition. A considerable group of “inter-
sexes” occurred, as evidenced by the secondary sex characters and the condi-
tion of the gonads as well. This was apparently a bimodal group, some of
intersexes being of a more “female type” and others of a more “male t
Cytological examination of these individuals revealed that the second ae
third chromosomes were regularly present in a triploid condition, that the
fourth chromosome was either diploid or triploid, and that two «-chromosomes
were regularly present (with or without a y-chromosome). The situation is
interpreted as follows. ‘It is not the simple possession of two x-chromosomes
that makes a female, or of one that makes a male. A preponderance of genes
that are in the autosomes tends toward the production of male characters;
and the net effect of genes in the x is a tendency to the production of female
characters. The ratio of 2x72 sets autosomes produces a female, while 1x:2

ae int

s
“‘superfemales,” and 1x73 sets autosomes “‘supermales.” The author has actu-
ally identified such types, both being sterile.

It is certain that this conception will exert a far-reaching influence upon
the existing ideas of sex-determination. In the first place, it gives a somewhat
more exact idea as to the elements effective in determining sex. Hitherto
it has been thought, rather vaguely, that the x-chromosome determines sex
either per se or by virtue of some special factor which it contains. It is inter-
esting to realize that a number of factors may be influencing sex in one direc-
tion or the other, and perhaps that these are identical with factors which have
previously been known as playing another réle. A different rate of metabolism
has commonly been associated with the two sexes; a study of the influence of
specific factors on metabolic rate now becomes significant in this connection.
In the second place, it furnishes an exact interpretation of intersexes on a
chromosome basis. Hitherto intersexes have either been interpreted in very
vague terms, or have been used as an argument against the chromosome theory
of sex determination, or have been harmonized with the sex chromosome theory
only by the assumption of some additional extrachromosomal influence
(GoLpscumipt). The present conception paints a quantitative picture of sex

410 BOTANICAL GAZETTE [DECEMBER

without calling upon any other effective elements than the ‘“‘orthodox”’ factors
of inheritance that are located on the chromosomes. In the third place, the
theoretical possibility of artificially controlling sex is illuminated. Such control
should be possible to the degree that the ordinary heritable characters can be
successfully duplicated artificially. The fact that the fourth chromosome
which is known to contain relatively few factors) 3 is preponderant in its
influence poe maleness suggests that a few ifi y be preponder
ant in influence. Artificial control, therefore, should necessitate the duplica-
tion of the effects of only a few of the factors. Also, the identification of
particularly effective heritable factors should be followed by the establishment
of a race with a heritably distorted sex ratio—M. C. CouLTER.

Taxonomic notes.—B¢RGESEN,’ in continuation of his studies of the
marine algae of the Danish West Indies, has completed the Rhodophyceae.
These two concluding parts include ror species, four of which are new, dis-
_ tributed among 29 genera. The following three new genera are established:
Cottoniella, Coelothrix, and Hypneocolax. An extensive appendix (86 pp.)
gives a list of the Chlorophyceae, Phaeophyceae, and Rhodophyceae found
at the islands, together with addenda and corrections.

ENGLER’ and his collaborators, in continuation of their studies of the
African flora, have published the following results: U Lpricu describes 4 new.
species of Pavonia; Mez describes 94 new species of grasses, 33 in Panicum,
33 in Melinis, and 18 in Digitaria; ENGLER describes 16 new species of Gesnera-
ceae, 14 of which are in Streptocarpus, and also establishes a new genus (Cleno-
cladus) of Moraceae; Wotrr describes 19 new species of Umbelliferae and
establishes Caucaliopsis as a new genus; KRAvusE describes 8 new species of
Liliaceae; IRMSCHER describes 7 new species of Begoniaceae; and BITTER, in
continuation of his monograph of African Solanum, has reached 56 species.

RyDBERG?, in continuation of his work on the Rosaceae, has presented
the roses of the Columbia region, which includes Oregon and Washington,
together with British Columbia and northern Idaho. In this region he recog-
nizes 37 species of Rosa and nine hybrids.

SCHLECHTER,” in reorganizing the classification of et ape pape
35 species of Spiranthes and establishes 16 new genera as follows, chiefly from
Mexico, the West Indies, and South America: Galeottiella, Hapolorchis,

7 BéRGESEN, F., The marine algae of the Danish West Indies. Rhodophyceae
(sand 6). Dansk Botanisk Arkiv 3: 305-408. jigs. 308-435. 1919 and 1920.

8 ENGLER, A., Beitrige zur Flora von Afrika. XLVIII. Bot. Jahrb. 75:161-
301. 1921.

9 RYDBERG, PER AXEL, Notes on Rosaceae. XIII. Bull. Torr Bot. Club 48:
159-172. 1921.

%0 SCHLECHTER, R., Versuch einer cies ies Oe ei der Spiranthinae.

Beih. Bot. Cestraine os: 317-454. 1920

1921| CURRENT LITERATURE 4II

Beloglottis, Mesadenus, Pseudogoodyera, Brachystele, Schiedeella, Trachelosiphon,
Deiregyne, Gamosepalum, Funkiella, Cladobium, Coccineorchis, Lyroglossa,
Pteroglossa, and Centrogenium.

STAPF" has established a new genus (Daturicarpa) of Apocynaceae from
the Belgian Congo. It belongs to the Tabernaemontaneae, and includes
three species of shrubs.—J. M. C.

ClasSification of symbiotic phenomena.—McDouGALt” has written a
very sensible and stimulating article on symbiosis and its subdivisions. Very
properly he disapproves of the numerous restricted definitions of the term,
going back to the original definition of DEBAry, which happens also to be the
only definition that justifies the retention of the word in the literature, and the
only definition that is etymologically correct. It is one of the curiosities of
biological science that so many writers have used the term symbiosis in the
sense of mutualism, a relationship that does not exist; and even if it did exist
we should not need two terms for the same relationship. The term is much
needed, however, in the original and correct sense of “the living together of
dissimilar organisms,” as pointed out by McDoucatt, for there is no other

erm of such broad and general nature. The author’s primary division of
symbiosis is into disjunctive and conjunctive, each in turn being subdivided
into social and nutritive; each type of nutritive symbiosis may be further sub-
divided into antagonistic and reciprocal. Plant communities illustrate social
disjunctive symbiosis; lianas and epiphytes illustrate social conjunctive
symbiosis. Antagonistic disjunctive symbiosis is illustrated by herbivores and
plants; antagonistic conjunctive symbiosis is illustrated by the ordinary cases
of parasitism, such as plant diseases, ectotrophic mycorhizas, etc. Recip-
rocal disjunctive symbiosis is illustrated by flowers and pollinating insects,
— conjunctive symbiosis by cases of reciprocal parasitism, such as are
seen in lichens, root tubercles, and endotrophic mycorhizas. McDovuGALi

condemns the eiioes view of some botanists that lichens are simply fungi.
He asserts that it is just as absurd to call a fungus-alga combination a fun-
gus as it would be to ges the term fungus to the mycorhizal combination of
roots and fungi.—H. C. Cowles.

Forests of British Columbia,—WuitForD and Craic have published
an admirable volume on the forests of British Columbia, which are among the
most interesting forests in existence. The report is based on three years of

= Srapr, O., Daturicarpa, a new genus of Apocynaceae. Kew Bull. no, 4. 166-
171. figs. 2. 1921

12 ipetiodudti: W. B., The classification of symbiotic phenomena. Plant World
21:250-256. 1918.

3 Sat H. N., and Craic., R. D., Forests of British Columbia. Rept.
Comm. Conserv. Canada, Committee on Forests. pp. 409. pls. 28. maps 21.
Ottawa. 1918.

412 BOTANICAL GAZETTE [DECEMBER

careful study, and it forms one of the most satisfactory volumes dealing with
forest resources that has come to our attention. The forests of British Colum-
bia are much more important economically than those of any other province;
indeed it is thought that the lumber resources of British Columbia are equal to
the combined lumber resources of the other provinces. The province has an
area of.about 356,000 square miles, of which more than half (200,000 square
miles) is unsuited to the production of merchantable timber, chiefly because
of altitude. Of the 156,000 square miles that might produce timber, 100,000
have been ruined by fire. As a matter of fact the land now clothed with
merchantable timber amounts to only 28,000 square miles. Since most of the
forest land is non-agricultural, a strong plea is put forth for reforestation.
The chapters in Part I deal respectively with geographical relations, physio-
graphic relations, climatic and soil relations, land tenure, forest administration,
forest policy, forest exploitation, forest trees, and insect injuries. The physio-
graphic chapter brings out the fact that British Columbia is “‘a sea of moun-
tains,” and that the average altitude of the province is 3500 ft. above the sea.
To the ecologist the most interesting chapters are the one on climatic and
soil relations, in which are discussed the various forest types of the province,
and the one on forest trees, giving a detailed account of each of the tree species.
About hal os the maps portray the distribution of individual species. The
plates grap f forest types and scenes.—
H. C. Cowtes.

Montane flora of Burma.—In sketching the vegetation of the mountains
of northeastern Burma, WARp* shows that a tropical rain forest of Indo-Malay
forms, such as Dipterocarpus, Shorea, Garcinia, Calamus, and Ficus, is found
up to an altitude of 5000 ft. From 5000 to 8000 ft. there is developed a temper-
ate rain forest, with Gordonia, Quercus, Magnolia, Acer, and Rhododendron as
characteristic species. Epiphytic mosses, ferns, and orchids abound, but
lianas are few. There follows a conifer forest extending from 8000 to 12,000 ft.,
which shows its tropical relationship only by the presence of species of bamboo.
Abies predominates, with some admixture of Pseudotsuga, Pinus, Juniperus,
and Larix. Rhododendron, with over 50 species in the undergrowth and in
the higher alpine scrub, ‘Rin. Rubus, Rosa, Philadelphus, Deutzia, and
Hydrangea are among the most abundant shrubs.

An examination of the flora reveals an admixture of Himalayan, Indo-
Malayan, Chinese, and endemic forms. This leads to the conclusion that this
mountain barrier, marking the eastern limit of the Indo-Malayan region for
75 miles, has been connected in the north with the Himalayan ranges on the
one hand, and with the great mace divide on the other, linking them in a
common center.—GEo, D. FuLLE

ARD, F. K., The distribution of floras in southeast Asia as affected by the
Burma-Yunnan ranges. Jour. Ind. Bot. 2:21-26. pls. 2. map. 1921.

GENERAL INDEX

Classified entries will be found under Contributors and Reviewers.

New names

and names of new genera, species, and varieties are printed in bold face type; syno-

nyms in italic.

Fier nvese don Sey in Brazil nut 284
Actinomyce 8

Aecio ospores, ptr of 173

African, flora 410; fortets 263; veld 56
Mi rolicani a 52

ter-ripening, ey of 139
ismaceae, leaves of 3

ed wee ea al eae ee oe
eee
& Be
Ey
a
tH
=}
Fifa GS
ol
i)
°

Of 333
\nthocyanin formation and organic acids
332
a paenare leaves of 35

Acoateene, BF E F., otk of 332

ur, 233. 2

Artschwager, e "Dictionary of botani-
cal equivalent:

Aspergillus a J Brazil nut 281

Astruc, A., work of 3

Bacteria, fetigite pags - Sag
Bacterial decay of Brazil n
ert ailey cE ay W., Feat of 53
~ °

atc: kk of 333
Baur, E., weak of x

e a a work of ‘4
Beloglottiz 4II

HF. 67 :
Bernard, N., Princioes de Biologie
vegetale”

Berthelot, M », work o

Bews, J. ora of” Natal and Zulu-
land” 408.

Blake, S. F., work of 51,

Blake slee, A. F. 162, ao ssn of 181

Bog plants, subterranean organs of 359
sak tar F., work o
tele 411

siete E., work of ae
Brazil nut, decay of 26

Brenchley, Winifred E., “Weeds of farm
land”’ 50

Bridges, C. B., work of 180, 408
British gaps ye ye of 411

Britton, a L., work of ee
Brown, uote of 5
Bru chmann, ‘Helmut, beranhesl sketch

of 4
Batiishaes, Ge rtrude S., = of 182
Burma, montane flora of 4
Butomaceae, leaves of 33

Calcicoles 54
Cambium, studies of 53
bell, D.

Camp’ H., work of :
a ero oreed Japanese 18
Carbohydrates, seasonal changes i in 263

Carboniferous wood, annual rings of
grow

Carica Pave, sa iop Magia fruits 97

Cartledge, J. L. 1

Carya alba, morphology of 375

Centrogenium

Chamberlain, c us 45, 55, 203, 331

Cheilanthopsis

Chelyoca =

Chlorophyll Schnritaiec II

Chodat, R., “Principes ae Botanique”
100; work of

La!
to

determination
5

Cladobium 4
Clements, Edith S., ve F. E., “Rocky
untain flowers

Coccineorchis 411
Coelothrix 410
en ig R., work ofs332
Conifers, notes on 55
ied halum conicum, chromosomes of

ee SR Arber, Agnes 31,
ur, J. M. 263, #3 Bau, U,
220; Bergman, H. : lakeslee,
A, F, 162, 185; Cake. J. 1a tha,

102;
RK.

414

185; Chamberlain, C. J. 45, 55, 203,
331; Cook, M. T. 250; Coulter, J. M.

2
Gericke, F. 404; Goldring, Wini-
fred 326; Harrington, L337;
Harris, J. A. 151; Heller, Hilda H
90; Hoerner, G. R. 173; Holm, aye

D. : He 305; Land, W. 1G
+ 393

.G. 262;° Welch, D: 8: 162, 185;
Yamanouchi, S. 90
Cook, M. T. 2

orallina ofcinalis, life history of 90
Cottoniella 4
oii eng “ood piety in 184
Mae 106, 109, I10,

Cunninghamella,. sexual dimorphism in

165
Cuscuta, revision of 51

Dachnowski, A. P. 57
Daturicarpa 411
Deiregyne 411
Densmore, iL D. Bi aa botany” 262
De Vries, H., work of 1
Diplacorchis| 182

n se, of economic plants 261; resist-

184

Doidge, Ethel a work of 51, 112
Dorman s, respiration of 1
Dragendorf, G., , ‘Plant analysis” 178
Drechsler, C

r, B. M., work of 184
E
Ecological, plant geography 407; research
54

Electric re effect on root tip 113
Embryogeny

INDEX TO VOLUME LXXII

[DECEMBER

Emerson, F. W. 359

Engler, A., work of 4

Epiphyte, Pebvocdion: vulgare 237
Everest, E., work of 332

Farnham, M. E., work of 181
Forest trees of Hokkaido 5
af of British Columbia 4
“An introdu wa to the
structure and reproduction of plants”

Fuller, G. D., 50, 53, 54, 5 112, 178, 262,
263) 204, 33%) 334, 4
Funkiella 4

Galeottiella “sige

Gamosepalum

Gangetic pas ecology of 264

Gericke, bg

Germinatio: chemjstry of 139; optimum
tem mera for

33
Glacier National Park, oe of 51
_ Gold E. ee ‘of

“Pehrbuch der dko-
logischen Pflanzengeographie” 407
Growth rings i

rings in a monocotyl 293
G :

yaladenia 182
Gymnosporangium cupressi 39

Hall, A. T., “Handbook of Yosemite
National Park” 178

Hoerner, £793
Holm, T.
Howe, Caroline

- Hughes, D. K., w

hs
Hyochartactae, alk, ‘of 36
ypneocolax

I
Illinois, flora of southern 263
Indian Bota ee Society 56
Tsoachlya 18

x
Johnson, D. 8. 237,
Juglans nigra, morphology of 375
Juncaginaceae, leaves
Juniper seeds, shetiatey of after-ripening

1921]

K
Kaufim aps ote ei of 183 ’
Keeble, F i‘ of 3
Kohler, Aiea work xf 333.
Kraus, fen work of 333
Kudo, Y., ” work of 55, 183

raed oa of Kurile Islands and Yezo

106
eae of Amaryllids 102; of Helobieae
Lennlcetaliuy a homosporous American

Lichens, destroying Sor eat

Lieske und Bio a
der Surahlenpile pve reliant v

Lindstrom, E. ME work of 111

peg W.) H. 3

Lower California, vegetation of 334
Lyroglossa 411
M

ilk Ouces), D. T., work of 54
McDougall, W. B., work of 411

Micronesia, flora of 5
Microthyriaceae, South African 51
iege, E., work of 332
' Mirande, M., work of 332
nr 3

Muller, H. J., work of 180, 182
Munns, E.
Murrill, ork of 18

~
WwW.
Mutant ~~ of Phaseoles vik 151
Mutation 1

N
Naiadaceae, leaves of 35

INDEX TO VOLUME LXXII

415

O
Odontopteris genuina in Rhode Island

Orchidaceae, African 182
Or. — acids and anthocyanin formation

aia pressure 408

Pack, D. A. 1
Palladin, V. I fee rk of 334
Palmer, E. J., work of 263
araguay, Feactation of 112
Paraphyadan
— ch edo sia iittle peach 250
eat deposits and climatic "or 57
erie material in root hairs 3
Peekelia 52

Peitersen, A. K., work of 336
Pennell, F. W., work of 51
effer, W., ‘‘Osmotische Untersuch-
2?

ung
Phaseolus vulgaris, mutant race of 151
ilippines, economic plants of 53
Phomopsis, bert s etianum 288; decay
of Brazil nu
-iper, North American species of 51
Plant analysis

olypores

hcinpetceas: leaves of 3

a enc dec ei artis of 183
00:

Q
06
Wo
ie}

» germination of aecio-
spores, urediniospores, and teliospores
173

Rafinesque, pees of
Ravenelia, scowl 42; fragrans
435 gooddingit 41; siliquae 43; sub-

Respiration of dormant seeds

rs Dictiona nary of
tanical ceclvalcets 110; neces
s de Biologie vegetale”
Bews’s Flora of Natal and ct %

ae Clem ents’. ** Rocky Moun

flo ”? so; Densmore’s “ Ciera
botany” 262; Dragendorf’s ‘Plant
ysis”. 178; Fritch’s “ tro-

duction to the structure and repro-
duction of plants” 109; Graebner’s

416

“Lehrbuch der dkologischen Pflanzen-

geographie” 407; Hall’s “Handbook
f Yosemite National irae Bast
Lieske’s ‘‘Mo logi d

der Strahlenpilze eee
“‘Osmotische Unter-

alis ’s n
srtitontlicl and
109; Sharp’s

the
reproduction of plants”
tology” 331; Simp-

“Int troduction to cy

for Warmin,
“Lehrbuch der Skolt Piniioe-
graphie’
Rhodophyceae of Danish West Indies 410

ers 50

Root, development of wheat seedlings
404; pectic materials in gets 313, effect
of direct current on tip 1

un
Rubus in New ak RE ‘336
ussula 182

Rusts, new or rare meee of 39
Rydberg, P. A., work of 410

Salisbury, E. J., “An introduction to the
structure and — of plants”

Sali, ‘amyadalodes 236; caudata parvi-
225; Gooddingii 227; laevigata
pone 234; lasiandra 222; lasiandra
Abramsi 224; lesa Wardii 2353
lucida ebiathe rissima
eella
Schlechter, R., ae of 182, 410
Foor t of location upon germina-

Seedling development, chemistry of 1
Seifriz, ork of 183 ie 6a,

W.,
Sex deeecitation ee cea 408
woe dimorphism in Cunninghamella

Sian. L. W., “Introduction to cytology”
I

aia ud

Shore p . Hlasiotopi 112

road, 0 rs M.,

Shull, C. A. 407, rd

Simpson, C. T., “In Lower Florida
39

INDEX TO VOLUME LXXII

[DECEMBER 1921

Souéges, R. M., ges of 56

Smiley, Edwina W., “Dictionary of
tictasical ecivalents” IIo

Spencer, E 265

Spiranthes 410

Stakman, E. C2

Standley, P. C., ne of 51

Stapf, O., wor

Stenodrepa num

Stipa, Australian ahectes of 5

pero tic phenomena, tla seiGenttot of

LEA, germination of 173
etra
Trachelosiphon 411

release, W., work of 51
Turesson, G., work of 112

Unwin, A. H., “West African forests”

202
Urediniospores, germination of 173

Virgin soil, invasion of 305

Ward, F. K., work of 4
rming iy “Lehrbuch = need
hie’

ol 54
Wheat geht, root abhor ae of 404
White mold of Brazil nut 276
hse H. a

t, J., work of 333
Willstatter R., gine of 332
inge, O., work of 111

Yamanouchi, S. go
Yo = a National Park, handbook of

Vacehee T. G., work of 51

Z
Zeleny, C., work of 179

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