THE oS
“BOTANICAL GAZETTE:
: TO s
: JOHN MERLE COULTER | i
Be ee VOIR
( 2 ‘i ne
ee
os) SOLYSDECEMBER gly
TABLE OF CONTENTS
The archegonium of Catharinea angustata Brid. (Airi--
chum — bee plates I-VIITI and one
takes place. In this process the cells of one of these longitudinal
_ rows divide parallel to the outer wall, thus se acentralrow
of cells (the canal row) surrounded ed by 4 peripheral cell rows. Later .
oe of these peripheral cells divide, thus iconnaco cells of the 8
4 BOTANICAL GAZETTE [yuLy
out 3 peripheral segments and originate a central cell. The central
cell now divides into an outer and an inner cell. The latter is
the first cell of the axial row. The outer cell grows considerably,
and again the 3 peripheral segments and the inner cell are cut off
The latter divides into an inner and an outer cell. Thus the
second cell of the axial row arises just as did the first, and KUHN
holds that all subsequent cells of the axial row are produced in the —
same manner.
In 1872 JANCZEWSKI (9) made a study of the archegonia -
several mosses. He names 2 species of Sphagnum, Atrichum (Catha
rinea) undulatum, Bryum crudum, Funaria hygrometrica, and Phas-
cum cuspidatum. JANCZEWSKI’s account of the development of
these mosses is very brief. He mentions only the chief points, and :
gives no details. It is unfortunate also that the paper has no illus-
trations. In regard to Atrichum undulatum, Bryum crudum, Funa-
ria hygrometrica, and Phascum cuspidatum, his chief points are
as follows: There is development by an apical cell with 2 uw a
- faces, producing a few-celled structure which at this time cant ;
be distinguished from a young antheridium. In the uppermos
__ cell, which is to be the mother cell of the archegonium proper, th
sae appear, = as ao. described for Andreaea, 3 oblique wall
_ cutting off 3 pe al segments and forming a funnel-s 14]
7 ues to act as an apical cell, cutting off ale pee: nt
rey state _ The number of canal i initials varies from 2 to 6
—_ cover cell may cut off 1, 2, or r3 peripheral segments bef
/ re a new canal, initial
1917] BRYAN—ARCHEGONIUM OF CATHARINEA 5
In 1884 Hy (8) summarized the archegonial situation in the
Musci as well as in other groups. His paper is noteworthy only
for its philosophical considerations. In a very general way he
confirms the findings of JANczEwskI, but adds little that is new or
convincing to the subject.
- In 1895 CAMPBELL (2, pp. 201, 202) studied the development of
the archegonium of Funaria hygrometrica. Here the first division
separates a basal cell from a terminal cell, which is the mother cell
of the archegonium proper. ‘In the latter 3 walls now arise, as in
the Hepaticae and Andreaea, but in Funaria they do not all reach
the basal wall, but intersect at some distance above it, so'that they
inclose a tetrahedral cell, pointed below instead of truncate.” The
tetrahedral cell makes the usual division into “‘cover cell” and
inner cell. The latter now divides, forming the primary neck canal
cell and the ventral cell. “‘The cover cell instead of dividing by
quadrant walls has a regular series of segments cut off from it and
acts as an apical cell. These segments are cut off parallel both to
its lateral faces and base and thus form 4 rows of segments, the 3
derived from the lateral faces forming the outer neck cells, and the
row of segments cut off from the base constituting the axial row
of neck canal cells.” As to the further growth of the canal TON,
SORE Ten so far as ld be det
do not divide after they are first formed.” :
GaveET (4) in 1897 undertook a ve-ezainination of the ole
question of archegonial development i in the Bryophyta, the i inves- a |
__ tigation covering numerous forms ae
the Musci. In the latter group, kis char basen ae tke :
_ ~present discussion, he mentions s species of Sphagnum, 2 of An-
Preden the following members of the a a,
Z | bec e : Summing up the m in points of his, sudy ( Gaver arrives . S :
hein. at
6 BOTANICAL GAZETTE [JULY
3- La cellule terminale ne donne point de cellules de canal, pas plus chez
les Mousses que chez les Hépatiques.
4- Les cellules de canal du col ont toutes la méme origine; elles provi-
ennent toujours d’une initale détachée de la cellule mére de l’oosphére; il n’y
ena point d’adventives qui seraient formées aux dépens de la cellule terminale.
GAYET’s conclusions, therefore, are diametrically opposed to
those reached by other investigators.
In 1898 GOEBEL (5) gives a rather brief and unsatisfactory
account of his examination of Mnium undulatum. He states
(p. 17): ‘I find in this plant confirmation through-
out of the statements of JANCZEWSKI and others, and
that the archegonium of the Musci is to be dis- —
tinguished from that of the Hepaticae by its peculiar —
apical growth” (text fig. 1). The cell represented —
as apical in this figure is most certainly not the one —
described by JANcZEWsKI. GOEBEL’s illustration |
would lead us to believe that the canal row has been —
formed by the activity alone of the one cell marked +.
formation described by Janczewskt. Hence GOEBEL
must be entete as giving an ans? different
: im reproduced once, and fig oon greece cell adding to the < do : 1
from Gorser’s row. In 3 other archegonia he shows the t topmo :
ee Sem canal cell i in the ‘Process of Len while i in one case
1917] BRYAN—ARCHEGONIUM OF CATHARINEA 3
8. The terminal cell adds to the growth of the neck by segments cut
from its 3 lateral faces, and to the growth of the axial row by segments cut
soe its truncate face.
Growth in length of the archegonium neck is intercalary as well as
wie in both neck and canal.rows.
SERVETTAZ (13) in a quite recent physiological paper on the
Musci includes an investigation of the development of Phascum
cuspidatum. ‘The developmental story is given briefly as follows
(p. 271):
La cellule initiale se cloisonne transversalment et donne une cellule de
peid, “‘a,’”’ et une cellule supérieure ‘‘b’’; la cellule ““b”’ se cloisonne ensuite
obliquement un certain nombre de fois (2-5) comme s’il s’agissait de consti-
tuer un bourgeon végétatif ordinaire, puis l’une des cellules placées au-dessous
de la cellule terminale se divise tangentiellement et détermine la formation
d’une cellule central “‘c” qui, par des cloisonnements basipétes, donne une
file de 8 cellules qui seront: 1-4, les cellules du canal; 5, la cellule du ventre;
6, Poosphere. ...
Quant 4 la cellule terminale, ey s,” elle peut continuer A se diviser et elle
forme la calotte recouvrant l’extrémité du col.
En definitive, le mode de formation que nous venons de décie se rap-
proche de celui que Goebel a décrit pour Mnium undulatum.
_ The evidence offered in support of this developmental story is
_ Certainly too meager and not sufficiently critical to be convincing.
- Moreover, the origin of the central cell, or first cell of the axial row, __
_ by a tangential division of one of the segments below the terminal
cot f is a k revival of the HOFMEISTER Conception: which mpegs ao
"nw oem @) dapemansasnaatan the archegonium ;
of S Te sections both transverse CS a
cle) Wicca Hide ‘had of the other Musci ce
8 BOTANICAL GAZETTE [JULY
make it certain that the growth of both canal row and peripheral
cells of the neck is intercalary and not apical.
SUMMARY
In regard to the formation of the archegonium proper in the
Musci 3 theories have been advanced: (1) the HOFMEISTER con-
ception of the tangential division of one of the 4 original pedicel
rows, a theory soon made untenable by the work of later investi-
gators; (2) a recent revival of the HorMEISTER scheme modified
by the tangential division of one segment only, as proposed by SER-
VETTAZ; (3) the commonly accepted account, confirmed again and
again for all the great groups of the Bryophyta, namely, the appear-
ance in the terminal cell of 3 oblique walls forming 3 peripheral
segments and an axial cell within.
It cannot be maintained, therefore, that the origin of the
archegonium proper is in doubt. The evidence is too overwhelm-
ing to admit of any uncertainty on this point. However, the
development of the axial row is another matter. Here is a subject
involving widely conflicting accounts, some being diametrically
opposed. Summarized, these accounts are: (1) the abandoned
conception of HorMEISTER, having only a historic interest; (2)
Kitun’s claim for Andreaea that all the cells of the axial row are
cut from the base of the apical cell; (3) CAMPBELL states for Funaria
_ that the axial row is composed of a primary canal cell and seg-
‘ments cut from the base of the apical cell, none of which divide —
after they are formed, so far as could be determined; (4) GorBEL
holds that in Mnium undulatum the topmost neck canal cell (the
‘one just below the cover cell) acts as an apical cell in the produc- —
- tion of the canal row; (5) Janczewskt finds that the cells of the
axial row are of diverse origins, the upper arising through trans- —
_ verse divisions of the 2-6 initials cut from the base of the apical
cell, while the lower are formed by the t jons of the
inal initial; © Hotrerty has shown ‘that the growth in :
- the canal row of Afni um Ch o
(7) Gavet concludes that, the canal cells among the Musci have
S all the s same ae : that there are no segments cut from the oe :
1917] BRYAN—ARCHEGONIUM OF CATHARINEA 9
initial produced by the mother cell of the egg; (8) SERVETTAZ states
that in Phascum the canal row is formed by the basipetal divisions
of the central cell; (9) the author has shown by division figures
that in Sphagnum subsecundum the growth of the canal row is
entirely intercalary.
It is evident that the Bryales are in need of a reinvestigation,
not a superficial examination of many forms, but a careful inten-
sive study of representative forms showing as far as possible by
actual division figures the course of development. It is with such
an idea in mind that the present work has been undertaken.
Development of archegonium
The apparently dioecious Catharinea angustata here studied
produces a fairly large number of archegonia on each gametophore.
The count shows variability with an average of about twenty.
As previously stated, young archegonia begin their appearance
early in April, and by the middle or end of May the majority ©
have reached maturity. The first archegonium arises from the
apical cell region, but whether from the apical cell itself or from
one of its immediate segments cannot be stated positively at
present. The study of the behavior of the apical cell in the pro-
duction of archegonia and the continued growth of the gameto- _
phore, if fertilization does not occur, must be reserved for a later —
paper. Tn its hy § stages tk a DY the usual eB
1ethod of an apical I cell with t vo cutting ; faces (igs. 1335, 7-9). .
n the 1. an Wawa ween a ce oe eptions to ;
this statement have been found a 2, 6). “In both cases. a
young ir very crowded quarters, being
ps chsely surrounded by the stalks of archegonia nearing maturity. _ Be
‘After a variable number of segments, — = have been oo
the apical « ell
ua UY | -
10 BOTANICAL GAZETTE [JULY
for Funaria, but extend to the basal walls. The primary axial cell,
therefore, has something of the shape of an inverted, truncated
pyramid. There now follows the division of the primary axial
cell into an outer axial cell, the cover cell, and an inner axial cell,
the central cell (figs. 12, 13). Quite soon the central cell divides.
the resulting lower cell being the ventral cell, while the upper
is the primary neck canal cell (figs. 14, 15). The actual division
of the central cell was found twice. The axial row of the young
archegonium now consists of the ventral cell; its sister cell, the
primary neck canal cell; and a large cover cell (figs. 15-17). :
It is interesting to note that in fig. 15 the original division wall
between cover cell and central cell appears tilted, due partly to the
inequality in the growth of the peripheral segments, and partly to
the change in the direction of the axis through the formation of
new peripheral segments by the apical cell. While this tilting is —
not always found, it is of frequent occurrence, as shown to a greater
or less extent in figs. 16, 18, 20, and furnishes valuable evidence in
separating that portion of the axial row derived from the central
cell from the part contributed by the cover.
The cover cell now cuts off peripheral segments ns 15-17).
No absolute Proof can be given as to their exact number, but it
series as figs.15-18 that there __
are e3 peripheral segments. Then there is added to the canal row
an initial cut from the base of the cover cell. The evidence for
this statement rests on fig. 18, on several others quite like it, and __
: is corroborated by the figures in the series about it (figs. 16-20).
similar series could be constructed from the material —
oe Sears A Jong and careful search failed to reveal the actual |
division figure, but in fig. 18 the size and position of the nuclei and _
2 z the delicate wall between leave no doubt that the uppermost canal
|) ow consiéts of the ventral cell; its sister cell, the primary r
a >I] has t cut from t base of the cover cell and that the: process a
has just: been completed. As illustrated by fig. 19 the axial Tow
canal cell; an initial cut from the base of the cover cell; and a large ae
: . cover cell or apical cell.
Up to this point the | process of development i is ae and deh
ease Meee tee ability shockir
1917] BRYAN—ARCHEGONIUM OF CATHARINEA II
one save an old-fashioned, rigid morphologist. After the first
initial has been added to the canal row, the apical cell again begins
to cut off peripheral segments (figs. 20, 23), but in the meanwhile
the periphery is also growing by intercalary divisions (figs. 10,
20, 22). While these peripheral processes are going on, the cells
of the neck canal row are not inactive. The primary neck canal
cell may divide first (figs. 20, 21), or the initial cut from the base
of the cover cell may make the first division (fig. 22). That there
are intercalary divisions in almost any order at this stage of the
process may clearly be seen from the series represented by figs.
25-28. The archegonium has now reached the stage when it con-
tains 4 or 5 neck canal cells. At this time the evidence is positive
that the cover cell adds a second initial to the row of neck canal
cells (figs. 29, 31). Fig. 29 illustrates excellently the intercalary
as well as apical growth of the archegonium. —
While fig. 31 is of interest in showing the activity of the cover
cell in adding an initial to the canal row, it has an additional inter-
est in giving evidence as to the origin of oblique walls in the axial
row. The axis of the spindle is tilted and an oblique wall is being
formed. In fig. 32 the process has been completed and the result
is very evident. There are then two ones eae the oblique walls ee
in the canal row. The first we have
fig. 15. No reliable evidence could be found that these walls
might arise in any other way, such, for example, & as the iepercniney ee
_ division of a canal cell. As a result of inter o
_ activity the canal row now contains 5~7 canal cells.
that follow there is no definite sequence that can
= oyster statement that can be mz de 1S 1
-* canal cells eased by intercalary aie
es ie, as:
VFS
- Just how active the cover cells at this time cannot the stated, . ap
I2 : BOTANICAL GAZETTE [JULY
Fig. 48 shows the formation of what is probably in the majority
of cases a last initial cut from the base of the cover cell. Abun-
dant evidence has been found that at some time between the 12-16
neck canal cell stage the cover cell changes its manner of division
and segments by a wall perpendicular to its base into two more or
less equal parts (figs. 50, 51, 54, 56). The division figure was
found once and is shown in fig. 56. No evidence could be obtained
that the division may occur before the 12 neck canal cell stage; while
after the 16 neck canal cell stage practically all covers showed
division. Out of the large number of cases studied only two excep-
tions were found, one a case of 18 neck canal cells, and the other a
case of 20 with the cover in each yet undivided. Such a process,
then, while occurring within general limits is by no means fixed.
Whenever such a division does occur, it signalizes the end of
all true apical activity. The segmented cover stands out well
defined from the peripheral segments of the neck and its history
can be followed for some time with a reasonable degree of accuracy.
Thus in figs. 61 and 62 the cover cell has formed 6 segments
(3 shown in median longitudinal section) and is literally the cap of
the archegonium. In fig. 72A we have the cross-section of the
_ cover of an archegonium containing 35 neck canal cells. It shows
7 clearly the primary: division es I-I}; the Lowap walls 2-2; and
th d When the archegonium
is fully matured the sepments oF the cover merge insensibly with
those of the neck, hence an exact statement cannot be made as to
the final number produced. | :
o The division of the ventral cell into ventral canal cell and egg
ae found five times, 3 being shown (figs. 47, 50, 53). Here again
: ‘ one finds the same sort of variability noted for the cover cell, but —
- with a slightly greater range. The division may occur as early
as the rz neck canal cell stage (fig. 47), while several cases were __
found in which there were 17-20 neck canal cells sath the Yentet yet :
ae / : undivided (figs. 58, 60). The ventral canal =
_ division is quite variable in size. Sometimes it is about the : shine
se ‘size as the egg (figs. 56, 6, 68); or it aay. ae Botiecably smaller
G54, 3,68).
_Asalready stated, the cutting off of initials from the base of the s
| one elem se eaneey of cases brought to a cx : :
: canal row in all of the cases observed was acro]
1917] BRYAN—ARCHEGONIUM OF CATHARINEA 13
where between the 12 and 16 neck canal cell stages; but since the
undivided cover cell may be found as late as the 20 neck canal cell
stage, it is evident that a variable number of initials may be cut from
its base. We have given proof that at least 3 initials are produced,
but we can make no positive statement as to the maximum number.
By making due allowance for the rapid intercalary growth, we
should estimate that in the majority of cases the number does not
exceed 5 or 6.
Whatever may be the number of initials, the fact remains that
both the canal row and the peripheral cells of the neck continue
to grow by intercalary divisions. Figs. 45-61 show some of the
many divisions found and furnish ample proof for the statement.
This continued intercalary growth finally produces an astonishingly _
large number of neck canal cells. In the material studied the
average count is well over 50; frequent examples in the sixties were
found; two in the seventies (one with 74 and the other with 76
neck canal cells); and finally one example in which there were 86
neck canal cells with several of the basal neck canal cells just
beginning to disintegrate. Not only is the number of neck canal
cells large, but the canal row is generally multiple in its upper part
(fig. 65). Less often this multiplicity is found through the middle
portion of the neck (fig. 66) and in the basal part of the canal row
(fig. 68). We have interesting evidence from fig. 64 that this _
multiple condition may arise by ie simultaneous division of the
° | ee
cells con .
7. stad of cross-sections through mature archegonia
1 the * oe
some interesting facts. A rey terminal
Opes te Sak G tho ne 69A-F. The canal row te not -
oS merely double i in this Portion: but generally consists of 3. cells and —
e peculiar enlargement of the canal at its
oe upper end is well shown by figs. 65, 60. The breaking down of the
opetal, but did not oe
is latter cell persists { for some:
4 time, oe its s history up to o featon has not been followed as oa
ium is not uniform Soe -
mu BOTANICAL GAZETTE [yoxy
two cases were found, one being illustrated in fig. 70. The arche-
gonium here contains 17 neck canal cells, 3 of which are shown,
and has 3 cells in the venter. It seems probable that the 2 lower
ones were formed by the division of the egg, while the upper is the
ventral canal cell which has remained undivided. Fig. 71 is the
reconstruction of a very remarkable double archegonium. It may
have originated by the fusion of 2 very young archegonia, or by the
longitudinal instead of transverse division of the primary axial cell.
Discussion
Catharinea undulata has been studied by JANCZEWSKI only.
The present work on the closely related C. angustaia confirms in
general his statements, especially in reference to the origin and
development of the canal row. There can be no doubt that the
cells of the neck canal row in C. angustata are of diverse origins.
The lower arise through intercalary divisions of the primary neck
canal cell, while the upper are produced by the intercalary divi-
sions of at least 3 initials cut from the base of the cover cell.
Aside from the activity of the cover cell, there is no evidence
that any one neck canal cell may act as an apical cell in the develop-
_ ment of the canal row. On the contrary, the evidence is clear that os
any cell of the neck canal row may divide and in any order. This
process is also in general agreement with the findings of HoLFERTY
ce for Mnium cuspidatum, where both apical growth and intercalary
__ divisions are reported. If Campsext is correct, Funaria shows a_
__ striking difference, in that the primary canal cell and the initials cut
a from the base of the apical cell do not divide after they have been.
f
f
- ormed; while GOEBEL’s account for Mnium undulatum shows still
oa urther difference, in that one of the neck canal cells at the apex of
Th
S _ the canal I cell 2 d by its activity produces the oF
] - further growth of the canal row. “a these differences are oe :
= _ firmed, Latex acake saasaews — g series in
"The facts i in ‘the present paper pe an eophatic decal of . —
the swe lizz
: 2 : pecenee give rise to neck canal cells. While the author has ce
shown in a previous Paper that in Sphapwum subsecandnem
tion of GavET that among the Musci_ the | :
1917] BRYAN—ARCHEGONIUM OF CATHARINEA 15
initials are added to the canal row by the cover cell, this investi-
gation makes it certain that in C atharinea angustata at least 3 initials
are produced. Just what type of development the representatives
of other groups of the Bryales will show remains to be seen.
Conclusions
The archegonium of Catharinea angustata grows for a time by
apical as well as intercalary divisions in both canal row and periph-
eral cells of the neck. In its later stage the entire growth is inter-
calary.
The cells of the canal row have a double origin. The lower are
formed by the intercalary divisions of the primary neck canal cell,
the upper through the intercalary divisions of the 3 or more initials
cut from the base of the cover cell.
How general this condition is among a Bryales must await
setipad work.
A
1. The archegonia of Catharinea angustata begin to sities Se
April.
a. The first formed archegonium arises from he apical cell
region, but whether fron the apical cell itself or from: one of its” pe
immediate. segments must be determined later. _ oS
3. In the ERGY shies ad Govelinunca the eeweg ecbagoaturn a
one
and | oe primary axial oll gong which on "division oS
gies te 6 Dee toler Gall sind the anand eel. oe
s ns aie conten call 00 division = rm he rinary ack ct =
16 BOTANICAL GAZETTE [JULY
8. The cells of the canal row and the peripheral cells of the
neck grow by intercalary divisions, and in any order.
9. The major growth of the archegonium is intercalary.
to. The cells of the neck canal row have a double origin. The
lower are formed by the intercalary divisions of the primary neck
canal cell; the upper through the intercalary divisions of the 3 or
more initials cut from the base of the cover cell.
11. The ventral cell divides relatively early into ventral canal
cell and egg.
12. The ventral canal cell is variable in size.
13. The mature archegonium has usually more than 50 neck
canal cells, and may contain as many as 86.
14. The canal row is generally multiple in its upper part and
occasionally throughout.
15. The disintegration of the canal row is acropetal, but does
not involve the ventral canal cell.
16. If the number of neck canal cells is an indication of primi-
tiveness, the most advanced group of the mosses has the most
primitive archegonium yet described among the Bryophyta.
UNIVERSITY OF WISCONSIN
1. BRYAN, GEO. ‘S., The t ium of sors bs lum. Bor. Gaz.
— $9:40-56. pls. 4-7. 1915.
2. CAMPBELL, D. H., Mosses and ferns. New York. ‘1905.
3- CHAMBERLAIN, C. J., Methods in plant histology. Chicago. rots. :
+ Gayvet, L. A., Recherches sur le développement de Varchégone chez les
- Muscinées. = Sci. — Bot. VIII. 3:161-258. ag 7-13. eile
5. GoEBEL, K., Sapecwreand of plants. Oxford. 190.
6. Ho a a
= V Reiman, Ents
. und F 1 ee eg oe | - T eipzi
7. Hoxrerty, G. M., The Pee of Mnium Baa Bor. Gaz.
-372106-126. pls. 5, 6. 1904. |
8. Hy, F., Recherches sur Parchézone ct le dé ppement du fruit
a cinées. Ann. Sci. Nat. Bot. VI. 18:105-206. pls g-r4- 1884. Ceo
o “p- Janczewst, E — Vergleict iiber die Entwick-
lungsge te Sn Bot. eit. 3 30137-3903, mE,
ro. eh naa t ag gsgt hick der Andreacaceen. ‘Schenk und
os nem gebe F Botanik. 4:51. a
1917] BRYAN—ARCHEGONIUM OF CATHARINEA 17
11. Lanp, W. J. G., Microtechnical methods. Bor. Gaz. 59:397-401. 1915.
12. SCHIMPER, W. Pu., Versuch einer Entwickelungsgeschichte der Torfmoose.
Stuttgart. 1858.
13. SERVETTAZ, C., Recherches expérimental sur le développement et la nutri-
tion des Mousses en milieux stérilisés. Ann. Sci. Nat. Bot. [X. 17: 111-223.
pls. 1-4. 1913.
EXPLANATION OF PLATES I-VIII
All figures were drawn with the aid of Abbé camera lucida at table level,
and, being reduced one-half in reproduction, now show the following magni-
fications: figs. 1-27, 870; figs. 28-35, 64-68, 700; figs, 36-44, 63, 690, 70,
72-74, X550; figs. 45-62, 410; fig. 71, X 225. Abbreviations are as follows:
a, base of older archegonium; /, leaf; p, paraphysis.
PLATE I
Fic. 1.—First archegonium arising from apical cell
Fic. 2.—Young archegonium with abnormal cross walls ‘ising at base of
ac archegonia.
Fic. 3.—Typical development by apical cell with 2 cutting faces.
Fic. 4.—The same, slightly older.
Fic. 5.—The same, still older. ‘
Fic. 6.—Development by walls which do not quite intersect; bases of»
older archegonia seen on each side of young archegonium. ae
Fic. 7.—Typical ieee older stage.
_ Fic. on
Fic. 9 lation t ] well shown.
Fic. 10—First archegonium arising ‘from apical cell region which has
now seg larly in terminal cell the first of the 3 oblique walls origi- .
2 etal a ag ee
ae HA t1--Tn terminal coll the 3 oblique walls heve:c t off per cet ae
"fests pul foc etary axial col wehin.
_ Fic. 12.—Primary : axial cell has divided into cover cell and central cell eS ae
_ Fic. 13.—The same,
Fic. 14.—Central cell dividing to form ey neck canal call and ven- ee
tral cell. a
Fic. 15—Division of central cll has just ben completed cover cell has :
noel es a
: ei Pee Bo su
Pe Pins ca cl
Fe ihe same; cover cell has formed = ress segm:
18 BOTANICAL GAZETTE [yuny
Fic. 20.—Two neck canal cells and ventral ote cover — forming a periph-
eral segment, while primary neck canal cell is in
Fic. 21.—Two neck canal cells and ar ac paieery neck canal cell
in divisio:
es 22.—Two neck canal cells and ventral cell; first initial cut from base
of cover in division.
G. 23 Lg SRG IRE VE ery | ai pe re 1 lI a °. Poe, al
eral segment
Fic. 24.—Three neck canal cells and ventral cell.
Fic. 25.—Three nee canal cells and ventral cell; middle neck canal cell
in division.
Frc. 26.—Three neck canal cells and ventral cell; topmost neck. canal
cell in division.
_ Fic. 27.—Four neck pane cells and ventral cell.
PLATE III
Fic. ee neck canal cells and ventral cell; second neck canal cell
from ventral cell in division.
Fic. 29.—Four neck canal cells and veopeal cell; simultaneous division |
pe ond pen ek oe while Cowes: cel AO@ 6 reve Metial to
Fic pan Tr, come ° 1 4}. me | ‘ut W Lay oe a
. .
1 segment.
- Fic. Stour neck cna ls nd venta cl cover cll ang second
ges age ce ee
— carom ase af cover cl ; eee -
ce "Fic. 35-—Five neck canal ells and ventral el; second neck canal cell
Pec 34-—Five neck canal cells ad ventral cell; stop 10S!
“Fic. o-Sewek can role ead sential oa : : .
Ne. ees —_ canal cells and ventral cell; pet 5 ck canal |
lel sees)
BOTANICAL GAZETTE
PLATE V
LXTV
E,
BOTANICAL GAZETT
<
A F Fre, SLOSS a
we!
+ Be, A) x
[ololoforeters
Ger { DSL
CO | Pes >\0\> Vie
: poo cre
- fe ge
Ge
eH,
ORAS:
PLATE VI
LXIV
,
BOTANICAL GAZETTE
Ty
ed 3
aes
- ets sy
ae
a.
(Vall 5
Ge : ek. ee nr es al
Coahuila, Mexico, September ara, 1904 ene in | Herb. NY. Bot. Gard).
Differs from B. procera Don in having ach
oe tert.
es ore aes ee From B. se Sosiaigons
26 BOTANICAL GAZETTE [JULY
characters respectively constant. This being true, it seems certain that the
15 or more beautiful plants collected by Palmer (no. 419), and all of them
having Lersca 4 elongate, very attenuate achenes, are likewise specifically
distinct
Bidens pseudalausensis, sp. nov.—Herba, verisimiliter annua,
circiter 6 dm. alta (ex Langlassei inscriptione), ramosa; caule et
ramis tetragonis et acute angulatis, striatis, glabris. Folia opposita,
petiolata, petiolo adjecto 2~7 cm. longa, 1-5.5 cm. lata, bipinnata,
glabra; ultimis lobis cuneato-oblanceolatis, dentatis dentibus ad
apicem induratis; petiolis o.2-2 cm. longis, ad basim connatis,
Capitula terminalia, tenuiter pedunculata pedunculis 1.5—-6 cm.
longis, ligulata, ad anthesin 6-7 mm. alta et (ligulis adjectis)
eirc. 1.5 cm. lata. Involucrum basi glabrum, squamis duplici
serie dispositis; exterioribus (circ. 8) linearibus, ciliatis, 2-3 mm.
longis; interioribus paulo longioribus, glabratis, margine diaphanis.
Ligulae (circ. 5) albae (e Langlasseo), in sicco specimine luteolae,
striatae, obovatae, ad apicem lobulatae aut obtusissime dentatae,
§-7 mm. longae. Achaenia (1-3 maturata in capitulis singulis)
linearia, nigra, faciebus plus minusve glabra, marginibus tuber-
culato-hispida, biaristata (aristis sub apicem retrorsum hamosis),
_7-9mm. longa.—Differt a B. alausensi H.B.K. habitu ramoso, etc.
-_ E. Langlassé 541, at altitude of 580 m., “El Ocote, Cerro Pedregoso,
Michoacan and Guerrero,” Mexico (type in US. Nat. Herb.).
- ‘Bidens aequisquama (Fernald), comb. nov.—Bidens rosea
Schz. Bip. var. aeguisquama Fernald, Proc. Amer. Acad. 43:68.
1907-
This rare species differs very markedly from Bidens rosea Schz. Bip., not
ee only in its involucres but also in its foliage and achenes. The type of B.
| rosea (Cosmos pilosus H.B.K.) is still extant (in Herb. Mus. Hist. Nat. Paris) _
and, though rather i immature, is not separable from such specimens as Heyde
and Lux 6172 and Palmer 192 i Coes, Proc. Amer. Acad. 41:
_ the type species of that genus (Cosmos
1917] SHERFF—BIDENS 27
conspicuous, averaging } to 3 the length of the achene body, and are armed
with many retrorse barbs that are not deciduous. Many other characters
likewise are pronounced, making it seem best, therefore, to give herewith a
full specific description, drawn from the type and various cotypes examined.
BIDENS AEQUISQUAMA, descript. amplificat——Herba, +5 dm
alta; caule ramisque pubescentibus aut subglabris, quadrangulari-
bus, striatis. Folia opposita, petiolata, petiolo adjecto 3-8.5 cm.
longa, indivisa aut tripartita, ciliata, supra subglabra, infra sparsim
adpresso-hispida et pallidiora; indivisis foliis lanceolatis, subcrasse
setratis; foliolis foliorum tripartitorum similiter serratis, terminali-
bus ovatis aut lanceolatis, lateralibus ovatis et subsessilibus et
minoribus; petiolis o.4—1.8 cm. longis, hispidis, ad basim connatis.
Capitula terminalia, ligulata, pedunculata, pedunculis 1-6 cm.
longis et ad apicem creberrime albido-pubescentibus. Involucrum
basi hispidum; squamis duplici serie dispositis; exterioribus (9-16)
linearibus, hispidis, 2-4 mm. longis; interioribus subaequalibus,
lanceolatis, glabris aut ad apicem et longitudinaliter medio hispidis ,
margine diaphanis. Ligulae (circ. 8) roseae, striatae, apice irregu-
lariter 2-4-dentatae, 9-11 mm. longae, 6-8 mm. latae. Paleae
lineares, margine diaphanae, 4-6 mm. longae. Achaenia nigra,
linearia, ad apicem plus minusve hispida, biaristata, aristis non
adjectis 4.5-7 mm. longa, flavis aristis retrorsum hamosis et
2.5-3 mm. longis.
“BIDENS SEEMANNIL”’ Seis. Bip ex Seem. Bot. Herald 307.
1852-57; Cosmos Seemannii Gray, Proc. Amer. Acad. 19: 16.
1883.
SCHULTZ ees beli
of separate treatment and accordingly Je united it with Bidens.
s ok
d th ey tu unworthy
But since his time, | — of the Compositae have per- as
sisted very uniformly in recognizing Cosmos as a distinct genus —
_ (cf. GREENE, Pittonia 4: 245. eon Indeed, the characters of :
ee
s Cav.) areso
4 Sree ice ke 6 ay went ak Senn Boe |
: __Bxos’ view wil ever be accepted by botanists inthe future. This.
28 BOTANICAL GAZETTE foxy
in a number of Cosmos species is the rostrate achenes. Cosmos
bipinnatus Cav., C. parviflorus H.B.K., C. caudatus H.B.K., C. sul-
phureus Cav., and C. ocellatus Greenm. are among those species dis-
playing this character in a marked degree. A study of such species
shows that the rostrate achenes are accompanied in almost every
case by two other characters; namely, some shade of red in the
ligules and the appearance of the interior involucre in the somewhat
immature heads, suggesting the conspicuous inner involucre found
so commonly in species of Coreopsis. But there are a few species
of Cosmos in which the mature achenes tend to be erostrate. Thus,
Cosmos crithmifolius H.B.K. and C. linearifolius (Schz. Bip.)
Hemsl., in the many specimens that I have seen, fail almost uni-
formly to exhibit achenes swollen below and distinctly long-rostrate
above as in C. bipimnatus. Yet in color of ligules and character
of involucre they harmonize perfectly with Cosmos. While
neither of these two characters is absolutely diagnostic, their
simultaneous occurrence, coupled with a tendency of the central
achenes at maturity to be elongate, even though indistinctly
rostrate, shows both species to be true Cosmos beyond all question,
and not Bidens.
Hemstey (Biol. Centr. Amer. 2: 203. - 3882), in dealing with
the Compositae of Mexico, very correctly considered these two
species as belonging to Cosmos. But “Bidens Seemannii,” a
species so identical generically with Cosmos crithmifolius that _
Hemstey himself erroneously referred to it Parry and Palmer
485 (true C. crithmifolius), he retained as Bidens. At a later date
Asa Gray suspected Ghiesbreght 264 of being “Bidens Seemanii”’
and stated that, if it was, the name should become Cosmos See-
mannii eee Amer. Acad. =* 16. 1883). In Gray Herbarium,
the ¢ breght | tudied by Gray is still preserved in
S pee Ss ideniical with Seemann 2or4 (in Herb. —
Kew), thus ction Gray’s supposition. It is accompanied
bya letter to Gray fron HEMSLEY, peters must have been written _ a
: Foren 1881 and Beha: ‘later than citi Ube « dates. of eae oe
1917] SHERFF—BIDENS 29
GREENMAN (Proc. Amer. Acad. 41: 265. 1905), relying upon
the erostrate achenes, retained ‘‘B. Seemannii” in Bidens.. But,
as might be inferred already, if this treatment were to be adopted,
then the subgeneric congeners of this species, such, for example,
as Cosmos crithmifolius, would likewise have to be placed in Bidens,
a procedure that surely would meet with little acceptance, if any.
Thus it seems best to follow the views of Gray and Hemstey in
this matter and treat the species as Cosmos Seemannii (Schz.
Bip.) Gray.
Besides th f C. Seemannii listed by GREENMAN (loc. cit.), [have
examined the followitig: J. N. Rose 3435, in the Sierra Madre, near Santa
Teresa, Terr. de Tepic, Mexico, August 11, 1897; Dr. Edward Palmer 1852,
Tepic, Terr. de Tepic, Mexico, January 5—February 6, 1892; Arséne, Cerro
San Miguel, Morelia, Mexico, February 1909.
“BIDENS PaLMERI” Gray, Proc. Amer. Acad. 22: 429. me
This species, with its strongly ribbed leaves, is very close to
Cosmos crithmifolius H.B.K., but cats in its oneal rays and
slightly different leaf outline. In most the achenes
are clearly erostrate, but occasionally some ‘of gral central achenes
become highly elongated above, appearing almost distinctly.
rostrate and thus exactly simulating those of such species as
Cosmos crithmifolius and C. linearifolius. This is especially no-—
table in certain material collected by Barnes and Land (nos. 164 —
and 189, in Herb. Field Mus.). In fact, the subrostrate character ee
of the achenes was known to Gray (cf. Gray, loc. cit., “ acheniis
subulatis ... subrostratis ”). Yet, curiously enough, he placed.
this species in Bidens, while previously (Proc. Amer. Acad. 19:
10. eS as shown
: above, to to the Chiact ght 5 it, described = himself as. wigs ae
30 BOTANICAL GAZETTE [yuLy
altitude of 1525 m., Rio Blanco near Guadalajara, Jalisco, Mexico, October
6, 1903; C. R. ga and W. J. G. Land 164 and 167, at altitude of 1707 m.»
Sierra de San Estaban, Jalisco, Mexico, September 28, 1908; idem 180, at
altitude of 1737 m., Sierra de San Estaban, Jalisco, Mexico, September 28, 1908.
BIDENS TENUISECTA Gray, Plant. Fendl. 86. 1849; Bidens
cognata Greene, Leafl. Bot. Crit. 1: 149. 1905.
In describing Bidens cognata, GREENE (loc. cit.) stated that
it was “‘allied to B. heterosperma.’’ He then proceeded to differ-
entiate it from that species, which was very easy to do because
B. heterosperma was so unlike it. Here, as in certain other cases
(cf. SHERFF, Bot. Gaz. 56: 494. 1913), GREENE’S error consisted
20 Soe: the plant to the wrong species and then founding a
upon the points of dissimilarity. His type material
o. B. Metcalfe 1436) is merely a low, rather much branched form
of Bidens tenuisecta Gray, with the type of which (in Herb. Gray)
it is connected by numerous specimens in American herbaria.
“Brpens DILtentana’”’ Hill, Veg. Syst. 3: 123. 176r.
This name seems to have escaped the serious attention of
botanists for more than a century anda half. The Index Kewensis,
although it cites the name, does not cite the habitat. Hiri
himself (loc. cit.) called it the “dwarf hemp agrimony” and stated
that it was a British n plant (“a petty plant of our own country’’),
but his g tration and brief description were entirely
too vague for satisfactory determination. However, on turning
to his earlier work (Brit. Herb. 461. 1756), we find (under Ver-
besina) a much fuller description of the dwarf hemp agrimony,
along with descriptions of what are now known as Bidens cernua
L. and B. tripartita L. This description and the earlier name
oe cited there by Hit, Verbesina minima Ray, show positively
that the plants later named Bidens Dilleniana were merely the
dwarf bog form of Bidens tripartita L. or the similar form of B.
oe : cernua L. - very a both these forms without distinction). oe
was given evidently for the very reason __
i - pane (Cat. Plant. Giss. 167, App. 66. 1719; ex Ray, ee
Syn. eae pl. 7. fig. 2. :
Flos was the one to introduce the name
1917] SHERFF—BIDENS 31
Druce (Fl. Berks. 283. 1897) has treated the dwarf form of
this species as “forma minima.” But it should be noted that
Drutce is not the first author to adopt this status, Larsson (FI.
Werml. 221. 1859) having used it long before. Similarly, the
dwarf form of B. cernua L., named “forma minima”? by Druce
(Herb. Dillen. 67. 1907), evidently under the impression that
such treatment was new, was already described, years before, as
B. cernua {. minima (Larss., loc. cit., 220).
BIDENS CERNUA L. Sp. Plant. 832. 1753; Bidens Kelloggii
Greene, Pittonia 4: 267. 1901.
A careful study of the type and other cited specimens of Bidens
Kelloggit (in U.S. Nat. Herb.) shows them to be incapable of
separation from B. cernua. GREENE classed these forms among
the segregates from B. laevis (L.) B.S.P., but most a
so, for, at the same time, he even stated that ‘‘Dr. Torrey . ‘
more correctly referred them to B. cernua.”
It may be remarked in passing that, in the future, es :
new species allied with Bidens cernua should be described only
after taking the utmost care to see that they are not mere atypic
forms of that species. It would be interesting | to subject B. cernua
to elaborate breeding experiments. A beginning in this direction
has been made already by Guppy (Studies in bent and Fruits
480. 1912).
BmweNs ALBA DC. Prodr. 5: oe 1836.—Coreopsis alba L
Sp. Plant. 908. 1753; Chrysanthemum americanum, ciceris folio
.... Herm. Par. 124. pl. 124. 1698; Bidens pilosa L. var.
Antill. 7: 136. 1o11; Bidens dondiaefolia Less. fe descript et
loci a Linnaea 5: 155. 1830. :
This peculiar plant was treated by DeCaxpocie as one of the
“species non satis notae.” I Ss n (
natis cuneatis serratis”) and ¢ citation’ of ‘habitat (“Insula St.
Cmeis”) e work of HERMANN, the
a Deas Batavus. Reference to this work (loc. cit.) shows a.
32 BOTANICAL GAZETTE [JULY
regarding it. Recently, however, there has come to hand (in
Herb. Field Mus.) a specimen (C. R. Orcutt 2886, Vera Cruz,
Mexico) which agrees most minutely and strikingly with Hermann’s
plate which Linnakvs cited; also another (idem 2991, Sanborn,
Vera Cruz, Mexico) agreeing satisfactorily but having proliferous
heads. Coming from the same locality in Mexico are other
specimens which show transitions to a more elongate type of
plant with some 5-parted leaves. One of these (Mueller 148, in
Herb. N.Y. Bot. Gard.) is labeled Bidens dondiaefolia Less., a
species likewise from Vera Cruz and the description of which it
fits very well (I have not yet seen LEssiNc’s type). It is note-
worthy that Lessinc called attention to the sterile shoots of this
species; ‘‘rami plures steriles.”
From these facts it is evident that B. dondiaefolia Less. is a
synonym for B. alba (L.) DC., and that B. alba is a local species
native mainly to the state of Vera Cruz, Mexico. It possibly
does not occur in St. Croix, as stated by Hermann (loc. cit.).
Dr. C. F. Mirispaucs, himself an authority upon the flora of
St. Croix, suggests to me, and very plausibly so, that in the prepa-
ration of HERMANN’s posthumous work, the name ‘Sancta Crux”’
perhaps became substituted for “Vera Crux,” and that thes the
locality “‘Insula St. Crucis” finally was published. __
As to the worthiness of Bidens leucantha (L.) Willd. to rank
separately from B. alba, future field observations and breeding
tests are highly desirable. It seems much the safer course to
retain the two names separately for the present rather than merge
them as done by O. E. Scsutz (loc. cit.).
The plant collected by Ghiesbreghit (no. 551) and referred be
Gray (Proc. Amer. Acad. 19: 16. 1883) to B. dondiaefolia is a
very | different plant and is typical B. chiapensis Brandeg. The
oo specimens of B. alba so far determined’ ©
a we myself a at the Field ‘Museum and the New York Botanical —
_ Garden (certa oo
1917] SHERFF—BIDENS 33
of Vera Cruz, Vera Cruz, Mexico, January 22, 1906; idem 97, along the shore,
north of City of Vera Cruz, Vera Cruz, Mexico, January 24, 1906; C. R. Orcutt
2886, Vera Cruz, Mexico, February 16, 1910; idem 2991, Sanborn, Vera Cruz,
Mexico, April 18, 1910.
BIDENS HUMILIS H.B.K., Nov. Gen. et Sp. 4: 234. 1820.—
Bidens consolidaefolia Tare Bull. Soc. Nat. Mosc. 24: 185. 1851.
TURCZANINOW (loc. cit.) based his species Bidens consolidaefolia
upon Jameson 693 from Quito. At Gray Herbarium is one sheet
of specimens by JAMESON “from the vicinity of Quito and else-
where,” and the specimens at the top of the sheet, while lacking a
number, match precisely the description of B. consolidaefolia.
It is seen from a study of many specimens of B. humilis collected
in the last half century, that B. consolidaefolia is merely a slender-
leaved form of B. humilis and is in no way specifically distinct.
BIDENS CONNATA Muhl. ex Willd., Sp. Plant. 3: 1718. 1804.
FERNALD (Rhodora 10: 197. 1908) has given an excellent
discussion of this species. Commonly it occurs with simple
leaves and then is the var. petiolata (Nutt.) Farwell, but occasion-
ally it possesses tripartite leaves, matching MUHLENBERG’s original ©
description of the species proper. In July 1913 it was my good
fortune to be invited to accompany Dr. FERNALD from Cam-
bridge, Mass., to Winchester, Mass., and there observe the tri-
_ partite leaves of the typical form, which grows in ¢ | quantity
' at that place. Tripartite leaves were prcscat on, young plants
less than 3 dm. high. In the Central United States, however,
ralaned
tripartite leaves ‘ce ae Pe pat AT large, robust ie aax
‘specimens. FERNALD (loc. cit.) gives the range for the typical,
| : = Michigan and “doubtless southward.” This range is. seen to : :
eee
a c. W. nae Miller, Indiana, i in an 0. E. Lonsing Jr. 1 "Rl : a
Indiana, September 16, 1899; idem 1170, pages Indiana, September 22, 1900;
, Roby, Indiana, § Ss
34 BOTANICAL GAZETTE [JULY
BIDENS FRONDOSA L. var. ANOMALA Porter ex Fernald, Rhodora
S? Or. 1903. :
' This variety is peculiar in having upwardly barbed awns, but
the precise significance of their occurrence is difficult at present
to judge. In a specimen of the corresponding form of B. connata
Muhl., the var. anomala Farwell, I have observed numerous down-
-wardly barbed awns in the same heads with upwardly barbed
awns (Vasey, near Georgetown, Washington, D.C., September
23, 1888, in U.S. Nat. Herb.). Wrecanp (Bull. Torr. Bot. Club
26: 415. 1899) cites also similar material collected at Ithaca,
New York. Frrnatp (Rhodora 15: 75. 1913) inclines toward
regarding B. frondosa var. anomala as a geographic variety. He
cites Pennsylvania, New Jersey, Delaware, also the region from
Maine to Cape Breton Island for its distribution. It is interesting
to note that out of many hundreds of specimens of B. frondosa
that I have examined from Europe and America, there were ob-
served only two instances of specimens of the var. anomala having
been collected outside the range given by FERNALD. These plants,
coming from Kansas and Nebraska, go further in showing the
distribution to be very discontinuous.
E. Hall, Kansas, in 1869 (in U.S. Nat. Herb.); P. A. Rydberg 1707, Middle
Loup River, near Thedford, Nebraska, August 26, 1893 (in Herb. Gray, etc.).
BIDENS ANGUSTISSIMA H.B.K., Nov. Gen. et Sp. 4: 233. 1820.
The type of B. angustissima is matched very well by ScHuLtTz ©
Breontinus’ type of B. linifolia (both in Herb. Mus. Hist. Nat.
Paris), except that the latter has only simple leaves, while the
former has tripartite leaves. Katt, in publishing the description
of B. linifolia (Flora 68: 203. 1885), described the heads as dis-
coid. But that rays were present on at least the Paris material
is shown by Scuuttz Brrontinvs’ label, in his own handwriting,
_ which reads, “achs. rad. calva ... .” Furthermore, PRINGLE
(no. 6924, granitic ledges at altitude a 2895 m., Cerro Ventoso
ee above F Pachuca, Hidalgo, Mexico, August 18, 1898) has collected ©
per — : sabe aoe eye gies and these all show :
> only differ- oe
1917] SHERFF—BIDENS 35
At Gray Herbarium there occurs a single sheet (Coulter 375,
Mexico) with three slender but well-developed specimens; the
largest one, at the left, matching the type of B. angustissima, and
the other two, at the right, matching the type of B. linifolia.
From these it appears safe to say that B. linifolia will be found,
on future field study, to be merely a simple-leaved state of B.
angustissima.
~BIDENS REFRACTA Brandeg., Zoe 1: 310. 1890.—Bidens
riparia H.B.K. var. refracta O. E. Schulz, Urb. Symb. Antill.
72 132. 19xt.
Scuutz (loc. cit.) regarded this species as only a variety of
B. riparia H.B.K., and he differentiates the two forms on the
basis of fruit chasachele But an examination of many specimens
of each form shows that the only genuine difference is in the foliage.
B. refracta has tripartite leaves, while B. riparia has bipinnate
leaves. This difference ScHutz seems to have overlooked. Indeed,
he even refers to B. refracta a plant collected by Tonduz (no.
13618, several fine specimens of which are in U.S. Nat. Herb.,
Herb. Brit. Mus., etc.) that is identical in foliage and other parts
with the type and Bonpland cotype of B. riparia (in Herb. Mus.
Hist. Nat. Paris).
Of 22 collections of B. refracta studied so far, I have seen only _
one instance where the leaves were not of the tripartite kind.
In this case (Jenman 5499, British Guiana, October 1889, in U.S. _
Nat. Herb.) the leaves are somewhat more divided, but still far
from resembling those of true B. riparia. The probabilities are
strong that B. refracta and B. riparia are entirely distinct species.
BIDENs s H.B.K., Nov. Gen. et Spec. 4: 238. 1820.—
Bidens tereticaulis De Prod? 5: 5938. 1836; Bidens antiguensis
Coult., Bor. Gaz. 16: 100. 1891; Bidens tereticaulis DC. var.
| antiguensis O. E. Schulz, Urb. Symb. Antill. 7: 142. 1911; Bidens —
_ tereticaulis DC. var. sordida Greenm., Proc. Amer. Acad. 39:
| 115. 1903; Bidens tereticaulis ‘De. var indivisa cere Proc. — .
Bost. Soc. Nat. Hist. ae 270. 1904; Bidens Coreopsi. C. var.
36 BOTANICAL GAZETTE [JULY
trisected, in having heads smaller, and in coming from a different
region (“‘Differt a B. squarrosa foliis glabriusculis . . . . capitulo.
minore, foliis etiam superis trisectis et patria’). But he had not
seen the type material of B. squwarrosa, as is evidenced by his
failure to use the abbreviation “‘v.s.’’ in connection with its descrip-
tion (Joc. cit., 599). At Paris (in Herb. Mus. Hist. Nat. Paris) is
still preserved KUNTH’s type of B.squarrosa. Upon the label are the
words “‘ Bidens squarrosa mihi... . Caracas.”’ This is positively
the specimen Kuntu had at hand in drawing up his description.
It consists of a branchlet coming from a portion of a stem. The
eaves of the branchlet are simple, as described by KunTH. One
well preserved leaf, still attached,’ and certain similar but more
fragmentary leaves, some of them broken loose, remain with the
stem proper. These leaves are very important, as they establish
definitely and beyond all question the identity of B. squarrosa
with pubescent forms of B. tereticaulis DC., and not with B.
reptans (L.) G. Don (with which it is equated by O. E. Schulz,
loc. cit., 140). This will become evident on reference to pl. IX,
drawn directly from the type with the utmost fidelity to all details.
The presence of pubescence in this species is not of specific
_ importance, a fact recognized by GREENMAN (loc. cit.) and by
Scuutz (loc. cit., 142) when they treated very tomentose specimens
as mere varieties of B. tereticaulis. Nor is the presence of several
or even many undivided leaves of decisive value, a fact recognized
by Rosrinson (loc. cit.) in treating as a variety of B. tereticaulis a
specimen with all of its leaves simple. That CoutrTer (loc. cit.)
treated his B. antiguensis (pl. X) as a distinct species? is easily
explained by the fact that the strong superficial resemblance of _
: his first type specimen’s foliage to that of certain hispid forms of
oS leucantha (L.) — led him to contrast seeds that species,
. raat ey ee a ae Ce ae
TATA ac
At least @ Bessa omc appa”
hencieat aes a Geen wee cs le
Os od certain
: genus Bidens, in the herbarium of Field Museum. a
tema be noted that the Gu setuid inca. 2h
1917] SHERFF—BIDENS 37
from which he very properly regarded it as distinct. It is inter-
esting to observe that CouLTER also noted the remarkable varia-
tion in pubescence (‘‘exceedingly variable in pubescence, from
glabrous to pilose-pubescent”’).
B. Coreopsidis DC. var. procumbens Donn. Sm. is a form of
this species. Its leaves are mainly 5-parted and are slightly
narrower than in most specimens. It approaches rather closely
B. reptans (L.) G. Don var. bipartita O. E. Schulz, of Porto Rico,
but as a rule is quite distinct from that form.
Since B. squarrosa thus is found to be so highly variable, it is thought
best to present here a rather full and representative list of specimens studied:
H. H. Rusby 1642, at altitude of 609 m., Guanai, Bolivia, May 1886; Mig.
H. H. Smith 519, at altitude of 609 m., Jiracasaca, Santa Marta, Colombia,
October 1898-1901; C. Hoffmann 383, Valley of the Rio Legardo, Costa
Rica; Ad. Tonduz Sooke at altitude of 1800 m., forests of the Mala Via at
Copey, Costa Rica, April 1898; idem 7265, banks of the Rio Maria Aguilar
near San Jose, Costa Rica, December 29, 1892; idem 13600, in thickets, Nicoya,
Costa Rica, January 1900; idem 7058, at altitude of rroo m., San Francisco
de Guadalupe, Prov. San Jose, Costa Rica, January 1896; idem 7248, in thickets
18, 1892; C. F. Baker 2121, Dept. Leon, Nicaragua, January 17, 1903; idem
_ 2214, Masaya, Dept. Masaya, Nicaragua, January 27, 1903; H. Pittier 1838,
at altitude of 600 m., in hedges around Copan, Honduras, January 9, 1907; —
Luis V. Velasco 8873, San Salvador, Salvador, December 1905; W. A. Keller-
man 5341, El Rancho, Sierro de las Minas Mountains, Baja Vera Paz, Gente:
mala, January 6, 1906; idem 5351, at altitude of 1205 m., Moran,
Guatemala, February 11, 1905; idem 6118, Volcano Acatenango, Chimalte 2
nango, Guatemala, February 8, 1907; idem 8035, at altitude of 1067 m., El.
Rancho, Sierra de las Minas Mountains, pais in toe temele, Jeetey
1908; Maxon and Hay 3162, at altit de m.,
_ Alta Vera Paz, Guatemala, January 4 1905; JZ ;
altitude of 1778 m., Antigua, Sacatepequez, Guat
an
D
and Lux 4193, at altitude of 1956 m., Buena Vis Pt anta
[ seh acer Ww. D. ASE at ee 79
38 BOTANICAL GAZETTE [JULY
February 12, 1905; Enrique Th. Heyde 666, Guatemala, in 1892; Berlandier
730 and 2150, Tantoyuca, Vera Cruz, Mexico, December 1830; idem 2148,
Mexico; Botteri 489, Orizaba, Vera Cruz, Mexico; Bourgeau 1560, Valley of
Cordoba, Vera Cruz, Mexico, October 12, 1865; idem 3093, Orizaba, Mexico,
October 3, 1866; C. Conzatti 122, at altitude of 1200 m., Mountains of Oaxaca,
Mexico, September 20, 1895; idem 1581, at altitude of 1800 m., Cerro San
Antonio, Oaxaca, Mexico, October 28, 1906; idem 2269, at altitude of 2000 m.,
Cerro San Felipe (Distr. del Centro), Oaxaca, Mexico, October 18, eS
Conzatti and Gonzalez 1133, at altitude of 850 m., Cordoba, Vera Cruz, Mexico,
December 1900; E. A. Goldman 30, at altitude of 244 m., near Metlaltoyuca,
Puebla, Mexico, January 27, 1893; idem 493, Apazote, Campeche, Mexico,
ember 28, 1900; E. W. D. Holway 3667, Oaxaca, Mexico, October 18,
1899; E. Langlassé 689, at altitude of 300 m., southern Mexico, December 2,
1898; E. W. Nelson 1508, at altitude of 1585-2075 m., Valley of Oaxaca, Oaxaca,
Mexico, October 2, 1894; idem 1824, at altitude of Bue ee m., 9.6 km.
above Dominguillo, Oaxaca, Mexico, October 30, 1894; idem 3410, near
Yajalon, Chiapas, Mexico, November 21, nen . R. Orcutt 3031, Sanborn,
Vera Cruz, Mexico, April 18, 1910; C. A. Pur 33, Zacuapan, Vera Cruz,
Mexico, October 1909; Charles L. Smith 298 say oS at altitude of 1955-2135
m., Monte Alban, near City of Oaxaca, Oaxaca, Mexico, October 1894; idem
<7, Coatzacoalcos, Vera Cruz, Mexico, February 6, 1895; Lucius C. Smith,
at altitude of sha5 m., Rancho de Calderon, Oaxaca, Mexico, September
10, 1894. :
Bidens Brandegeei, sp. nov.—Herba annua, erecta (nisi infra
plus minusve arcuata), 3-5 dm. alta, maximam partem albido-
hispida. Caulis quadrangulatus, striatus, ramis tenuibus ramosus.
Folia opposita, petiolata, petiolo adjecto 1-8 cm. longa, pinnata aut
bipinnata, supra minus albido-hispida; foliolis 3-5, ovatis (aut
ovato-lanceolatis) serratisque et non dissimilibus iis B. leucanthae
_(L.) Willd., aut pinnati partitis, lobulis aut dentibus indurato-
apiculatis; petiolis o.2-2.5 cm. longis, basi connatis. Capitula
_ pauca, terminalia, ligulata, tenuiter pedunculata, pedunculis
_ monocephalicis, 3-8 cm. longis. Involucri squamis subaequalibus
_ duplici serie dispositis; exterioribus (circ. 8) linearibus, 1-nervatis,
/ apiculatis, albido-ciliatis st-hispidis, 4-5 mm. longis; interioribus —
1917] SHERFF—BIDENS 39
T. S. Brandegee, in vicinity of San Luis Tultitlanapa, Puebla, near the
Oaxaca boundary line, Mexico, in 1908 (first type sheet in Herb. Univ. Cal.,
herb. no. 134267, and second type sheet, dated July, also in Herb. Univ. Cal.,
herb. no. 134268); C. A. Purpus 4429 (in vicinity of San Luis Tultitlanapa,
Puebla), Oaxaca, Mexico, August 1
species having at times all the ‘lentes tripartite and then deceivingly
like B. leucantha (L.) Willd. except as to achenes. The description is drawn
mainly from the two flowering specimens on the first type sheet, but the
achene characters are described from the single fruiting head present on the
writings ae exteyled our knowledge of this genus to a considerable extent.
Recently, Dr. Smney F. BLAKE has sent from Gray Herbarium
a specimen of Bidens that appeared to him as allied with Bidens
rubifolia H.B.K., but none the less new. The plant was collected
by Hotway in Guatemala early in the present year, and is described
by him as “climbing over trees 40-50 — and then dropping down
nearly to the ground.” Its heads, i asure about 6 cm.
in diameter. From B. rubifolia it may easily be recognized in
behead specimens by its large involucre and the unique char-
acters of the involucral bracts. + detailed description is peeento
here:
Gelcie Visine Shcee and Hiake: sp. nov.—Herba scandens,
-caule demum 20-30 m. longo, ascendente (ex Hotwayo) in altitu- |
dinem 12-15 m.; ramis tetragonis, glabris, striatis. Folia opposita,
petiolata, petiolo adjecto 6-18 cm. longa, tripartita aut summa indi-
visa, ciliata, supra glabrata (nisi ad venas), infra plus minusve
piloso-hispida, serrata; foliolis lateralibus ovatis aut ovato-lanceo- oe
latis, terminali ovato-l: dla aut | 1. to. ‘Petioli I. - 5 4em. 2 Q
40 BOTANICAL GAZETTE [JULY
diaphanis. Achaenia linearia, subplana, nigra, ciliata, ad facies
sparsim hispida, 1.3 cm. longa, ad apicem nonnullis erectis setis
coronata, biaristata aristis retrorsum hamosis et divaricantibus.
E.W. D. Holway 816, Quezaltenango, Guatemala, January 31, 1917 (type
in Herb. Gray).
BIDENS SAMBUCIFOLIA Cav. Icon et Descript. 3:15. pl. 229.
1794; Bidens alamosana Rose, Contrib. U.S. Nat. Herb. 1:104
pl. 6. 1891.
A comparison of the type illustration of Bidens alamosana with
that of B. sambucifolia reveals a remarkable similarity. Further-
more, the descriptions of the two species are very close and differ
materially only in that the ligules of B. sambucifolia are described
as scarlet; those of B. alamosana are yellow or orange-yellow.
CAVANILLES’ description was based upon material from the
Royal Garden at Madrid and which was stated by him to have
come originally from Peru and Mexico. It may well be that his
citation of Peru was entirely erroneous, as I have never been able
to find a specimen from elsewhere than Mexico. An examination
a numerous specimens collected in Mexico shows the ligules to be
: y yellow or orange-yellow, but in certain rare cases the ligules
nae the dried specimens) have a color so reddish as to explain quite
plausibly how Cavanilles was led to call them scarlet (“corolla
to the en Gaunns (4) found di-potassium phosphate neutral -
in its effects upon the burn. =
sk consideration of the reason, for the aE in of
: the potassium salts of organic acids has led to several theories. oe
: SCHLOSING (15) attributes their favorable action to the fact t that os
: and y Se $ mass. soa ee (2)
44 BOTANICAL GAZETTE [yoLy
oxygen carrier. MAvYER (10) also attributes the beneficial effects
of the alkali salts to the fact that they are easily reduced. BArTH ©
(1) suggests that the salts may have a beneficial action by raising
the temperature of the leaf; he also attributes the harmful effect
of the chlorides to the fact that they fuse and coat over the material,
thereby preventing complete combustion.
Object
The object of this work is to study the effects of various salts
closely related to the salts of potassium with a view to obtaining
some light upon the conflicting theories. It has been suggested
that the effect of the various salts upon the colloidal state of the
material of the leaf may bear some relation to the problem. It
was thought that probably potassium possesses some peculiar
_ chemical properties which may account for its action.
ses of salts upon combustion of tobacco
METHOD
‘The method of experimentation consisted of treating leaves and
filter paper with various salts and noting their effect upon the
__ fire-holding capacity. The samples of tobacco used in this work
a Jeete OF 8 sine brain, of a tear Hiden pe oe tobacco grown in
oe under definite fertilizer treatments. The leaves
y had been well sweated. In all cases the solutions of
Ej rapoadiess were 28.9 per cent normal. In order to see
__whether the effect of the salts was upon the colloidal state of the
oe Rioiee by a treatment with o.2 no
ue materials of the leaf, some of the leaves were rendered acid by
_ treatment with o.5 normal acetic acid, and others were rendered :
1917] KRAYBILL—ALKALI SALTS 45
expected, due to variations in different leaves, the results were
not always consistent in some cases where the comparative differ-
ences were small, but in each case a number of tests were carried
out upon a number of different leaves until the average results were
considered reliable for the purpose of comparing the effects of the
various salts. :
DATA
Because of the similarity in chemical behavior of the alkalies
caesium, rubidium, potassium, sodium, and lithium, it was thought
that a comparison of the effects of their salts upon the fire-
TABLE I
LEAVES FROM PLATS FERTILIZED WITH MANURE ONLY
Average number
Average number] of seconds in-
Salt treatment Other treatment ‘Number of tests} of seconds | creases fire-
50 7 60
a0. 40 Pee
60 18 oU§
Se 19 we
10 59 45
ee 44 35
fe. 18 Io
9. a) aS ae
9° eee a ae
oe (68 Se
= 7 oe
46 BOTANICAL GAZETTE [yULY
a minor factor. According to H6BER (5), the relative effectiveness
of the alkalies i in precipitating colloids in an acid medium is as
follows: lithium>sodium>potassium>rubidium>caesium. In
an alkaline medium the order is as follows: caesium >rubidium >
potassium >sodium>lithium. In the cases where lithium is more
1 ae
TABLE II
LEAVES FROM PLATS FERTILIZED WITH POTASSIUM CHLORIDE
Average number
Average number) of seconds in-
Salt treatment Other treatment Number of tests} of creases
holds fire holding ca-
pacity
pS a 2s as o.2/N NaOH 60 54 49
Nats. 2.56... . 60 2r 14
oO eS eee . . 60 16 10
RANK. o.5/N acetic acid 20 27 24
NaCO,. . 2.25... -5 . 20 8 5
BAAR. ee ee 20 9 6
Cs,CO;. Nothing 20 61 57
RAMS. oo 30 40 36
ENN. oa oe. e: 20 48 44
TABLE III
_ LEAVES FROM PLATS FERTILIZED WITH MANURE ALONE
'
1917]
minor importance.
KRAYBILL—ALKALI SALTS
47
It seems very evident that of all the alkali
carbonates only those of caesium, rubidium, and potassium mate-
rially aid the fire-holding capacity.
Table III shows that of the oxalates of potassium, lithium, and
sodium, only the oxalate of potassium is effective in increasing
TABLE IV.
LEAVES FROM PLATS FERTILIZED WITH MANURE ALONE
Average nu
Average number! of seconds in-
Salt treatment Other treatment Number of tests} of seconds creases
pacity
Potassium Aisi .-.| 0.2/N NaOH 30 29 13
Sodium citrate. ..... . 20 1§ 4
pteocheres on eos oh. _ 20 16 6
Potassium citrate....| o.5/N acetic acid 20 30° 19
Sodium citrate. ..... . 20 18 I
Lithium citrate......| . 20 19 -
Potassium citrate Nothing 20 24 18
Sodium citrate. ..... ” 20 10 4
Lithium citrate . 20 Ir 5
TABLE V
LEAVES FROM PLATS FERTILIZED WITH POTASSIUM CHLORIDE
ie! j ats 7 Ny } , : Hebe «Se . : =
Potassium citrate... 0.2/N NaOH 50 28
Sodium citrate...... ae 50 Ir
Lithium citrate......) Pe ge we
‘Potassium citrate....| o.5/N acetic acid 20 37
Sodium citr: eels Seog 20 10.
Lithium citrate. . . 20 > ve
- the fire-holding cz capacity. ae again in the cases sates i lit rit 2
Ss more effective than sodium i in the ——* ofc colloids,
48 BOTANICAL GAZETTE [JULY
Table VI shows a comparison of the results of a number of
potassium salts. All of the potassium salts are very effective in
promoting the fire-holding capacity, with the exception of the
chloride, acid sulphate, and mono-potassium phosphate, which
TABLE VI
LEAVES FROM PLATS FERTILIZED WITH MANURE ALONE
Average (Average ——
| Number of | Bumber.of | of seconds i
teste ehissaeay Sage
ee
Se ee Oe ee §
|
he
UnPawwHann | |
x09) KRAYBILL—ALKALI SALTS 49
are either nearly neutral or exert a harmful effect. It is quite
evident that none of the sodium salts exert the marked beneficial
effects which some of the potassium salts exert.
Effect of salts upon combustion of lump sugar
The effect of various salts of the alkalies upon the combustion
of different kinds of paper and lump sugar was also studied;
although, as one would expect, due to the dissimilarity of materials,
the results in these cases were not always parallel with those upon
tobacco. The results with lump sugar are particularly interesting.
In each case a small portion of the salt was placed upon the lump
of sugar and then an attempt was made to burn the sugar by
touching it to a gas flame. The results obtained are indicated in
table VIII.
Discussion _
SCHLOSING (15) attributed the favorable action a the organic
salts of potassium to the fact that they swell up and yield a porous
mass. NESSLER (12) combated this idea and showed that other
salts of potassium which do not swell so much when heated also
have a favorable action in promoting the fire-holding capacity of
tobacco. GARNER showed that the carbonates of potassium are
ve just as effective as the organic salts. From resnabhee a -
_ These results confirm the conclusions « 2 stnasosypaancice
indicate that the good effects of the potassium salts of organic a
acids cannot be attributed to the fact that — swell and _ oS
5° BOTANICAL GAZETTE {JULY
represents their increasing ease of reduction in solution. If we
assume that this represents the order of the ease of reduction of the
TABLE VIII
EFFECT OF SALTS UPON THE COMBUSTION OF LUMP SUGAR
Salt Effect
a ak 8 PM Ee eee Lump of sugar burned with flame; sugar coaled
Rb,CO;. een es “ “ & “ “ “ “ “
8 pS OAR ee SS - : . - .
Na.CO, a ee “ce ac “ee ““c “ce “ce “é “ce
: Live... ee “ “ “ “ “ “ “
Baw). o.oo ake of sugar burned slightly; _ coaled slightly
KarO,.. ....2.5. Lump of sugar burned; sugar coal
Bre. ce. Lump of sugar baraed teh ange coaled slightly
Mahe ck eee Lump of sugar b
| Se ee ae 9
4 8 pe ,..Lump of eisptcius ae sack, sugar coaled
Potassium acetate ..Lump og sugar burned with flame; sugar coaled
Potassium citrate. oe “ “ “« “ “a “ “
Potassium oxalate ...* “* * . . ie * «
Pomme. © © © © & & * 8
ii tt 2 * .
iithua wales... *. * * 5 * “ “ “
Lihtuncinie..... * © *: . . é, i “
3 UES RRS i ec aie
ere ~ home of saat boned 958 Fame puget coaled
_ Sodium oxalate... ..
oy een eS eS "daa haga wiinad Vial sore did not coal
7 iy Sugar melted; did not burn with flame; did not coal
Na,SO,. .. panic d slightly; sugar —
ea ee Sugar melted; did not burn with flame; did not coal
P
A Pe peo) ane meee ae Dae a
oo BaCO,.. L. |
1917] KRAYBILL—ALKALI SALTS 51
alkali carbonates, it would be difficult to explain by NEssLEer’s
theory why lithium and sodium carbonates are not effective, and
caesium, rubidium, and potassium carbonates are effective.
GARNER (4) suggests that the carbonate might act favorably
by alternately giving up and taking on carbon dioxide. We have
seen that caesium, rubidium, and potassium carbonates are very
much more effective than the carbonates of sodium and lithium.
At joo C. the order of the alkali carbonates according to their
increasing ease of dissociation is as follows: potassium, rubidium,
sodium, caesium, and lithium. Lithium carbonate is dissociated
into carbon dioxide and lithium oxide to a much greater degree
at 7oo° C. than any of the other carbonates (9). If potassium
carbonate acts favorably by alternately giving off and taking up
carbon dioxide, it is difficult to see why lithium carbonate should
not be even more effective. It seems, therefore, that this theory
will not explain the beneficial action of the caesium, potassium, and
rubidium carbonates.
From table VIII we see that all of the salts which were effective
in increasing the fire-holding capacity of tobacco will cause the
lump of sugar to burn with a flame when ignited by means of a
gas burner. Some of the salts which were only slightly effective
in increasing the fire-holding aia d of + AED, such as nthe
the combustion of sugar with the production. of a flame. ‘Here
again caesium, potassium, and rubidium cecuutes are particu- —
larly active. Barra (1) has suggested that the salts present in —
the leaf may aid in the combustion by raising the temperature
of the leaf, the effect being somewhat analogous to the effectof
salts upon raising the boiling point of water. As shown i in table :
VIII, such substances as metallic fili | ind
bonized sugar when used in larger pial also ar a.
: eee et ee to burn. From these eaten
> sugar, it would seem as though their effect in raising —
52 BOTANICAL GAZETTE [JULY
marked effect in promoting the combustion of tobacco. SLIGH
and KRrayBILL (16) have determined the temperatures of burning
cigars and have found some evidence which suggests that the
moisture content as well as the composition of the cigar has an
effect upon the burning temperature. It is planned to study this
problem further with the object of determining the extent to which
this hypothesis may be applied.
BartTH (1) considers the harmful effect of chlorides to be due
to the fact that they fuse and coat over the material, thereby
preventing complete combustion. SLicH and KRavyBItt (16) found
the temperature in the cigar varying from 813° C. to 925° C. during
a puff, and from 584° C. to 803° C. at stationary temperatures
between the puffs. It is doubtful whether the temperature of
the burning strip of a leaf of tobacco would be as high as these
stationary temperatures of the cigar. The temperature of the
leaf then would not be high enough to fuse pure sodium chloride
or pure potassium chloride. It would seem then as though the
theory of BARTH would not account for the harmful effect of the
chlorides. An objection might be raised from the standpoint ,
that we have in the leaf mixtures of salts, and that their fusing
‘points would be lower than that of the pure salts. The fusing
point of sodium chloride is about 820° C., and that of rubidium
: carbonate is 837° C. (9). Tt would he Gilet te anileeatnad why ©
= one salt should harm the burn by fusing and the other should -
ee the ‘same tem-
perature.
An attempt was ‘ead: to tabulate and compare the chemical
and physical properti ee eee celia eh Ue hope of merci
a ae the melting points, specific heats, weed ok ‘vaporization, ot
dissociation | rbon A very careful com-
1917] KRAYBILL—ALKALI SALTS 53
not be due in part to the alkalinity of the salts in solution. Such .
an explanation, however, would not account for the behavior of
the sodium and lithium carbonates.
Extremely small amounts of caesium, potassium, or rubidium
carbonates greatly increase the fire-holding capacity of the tobacco.
A 2 per cent solution of potassium carbonate applied by means
of an atomizer to the leaf was sufficient to produce the effect.
Upon examining the ash left after the combustion, the potassium
was found as the carbonate, that is, in the same form in which it
was present before the combustion. It is possible, therefore, that
certain salts, such as the carbonate, phosphate, and sulphate of
potassium, and the carbonates of rubidium and caesium, act in a
catalytic manner to promote the combustion of the tobacco leaf.
In the combustion of lump sugar other salts are also effective,
but the carbonates of caesium, potassium, and rubidium are more
effective. Here the effect of the salts in raising the temperature
may be important.
According to this al . raecdim chiinnkle. ceramann educa
bonate, rubidium carbonate, tri-potassium phosphate, di-potassi
phosphate, and potassium sulphate have a catalytic action favor- _
ing the combustion of the tobacco leaf. The salts of sodium _
and lithium, potassium chloride, mono-potassium phosphate, and —
_ acid potassium sulphate do not have this catalytic action. The
harmful effects of the chlorides seem a ane ele eameien
Ta 5 ye ere pe ra) 1.
eu eueacs - Vs SAA
when various organic materials, srpepertial ay and: sugar
- treated with the - are a to te ur |
ee Ner (zx) has studied the e 1 the oxidation of _
x a oS in a solution | at low ek
xidation of 1
nical acti retaning
sconce -
54 BOTANICAL GAZETTE [JULY
Summary
1. The alkali carbonates of caesium, rubidium, ana potassium
have a definite marked effect in promoting the fire-holding capacity
of tobacco, which sodium and lithium carbonates do not exhibit,
the order of effectiveness being as follows: caesium, rubidium,
potassium.
2. Of the oxalates tried, only potassium is effective. In the
case of the carbonates and the oxalates in an alkaline medium,
where lithium is more effective than sodium in the precipitation of
colloids, it is slightly more effective also in promoting the fire-
Iding capacity. In the case of the citrates there is no such
relation and, in the case of the carbonates, potassium, rubidium,
and caesium do not behave in this manner. It is doubtful, there-
fore, whether the effect of the salts upon the colloidal state of the
tobacco leaf is of any significance.
3. Only potassium citrate is effective in promoting the burn.
The citrates of sodium and lithium are nearly neutral in their effect.
4. The organic salts of potassium, potassium carbonate, tri-
potassium phosphate, di-potassium phosphate, and potassium sul-
phate improve the fire-holding capacity; while potassium chloride,
acid potassium sulphate, and mono-potassium gee ears are inju-
rious to the burn. |
Sodium 1 eh, eee a . yy : 2 4 at
7S holding y slightly, —
while all of the other sodium salts a are either neutral or injurious
to the burn.
ee The data obtained do not confirm the idea that the reduction
_of the potassium salts will account for their favorable action.
7. Data are given which indicate that the harmful action of
: chases is nde $6 the fark Cat they fae ee
oo Data are given which indicate oats the alternately giving
___ offand taking up of carbon di
effects of potassium carbonate.
ae a bes of s € Si l oni :
- Bs eric of the salts i in ‘raising the fe oa
1917] KRAYBILL—ALKALI SALTS 55
11. It seems probable that caesium, potassium, and rubidium
in the form of certain salts, such as the carbonates, sulphates, and
phosphates, have a specific catalytic action in the combustion,
and that the chlorides have a negative catalytic action. It is
planned to study the rate of decomposition of various organic salts
of the alkalies, and also the decomposition products of various
organic substances treated with salts of the alkalies, when sub-
jected to temperatures which are attained in the burning cigar.
Acknowledgments are due to Dr. Wm. Crocker for many
helpful suggestions and criticisms, and to Mr. Orro OLson of the
United States Department of Agriculture for the = of tobacco
used in this work.
UNIVERSITY OF CHICAGO
LITERATURE CITED
1. BARTH, Max, Untersuchungen von im Elsass ~ gesozenen Tabaken und
einige Beziehungen zwischen der Qualitat des Tabaks und seiner Zusam-
. Landw. Ver. Stat. 7 ua he ok,
2. BEHRENS, J., Weitere Beitrige zur Ker Tabakpflenze. Landw.
Ver. Stat. 43: he 1895-
3- CARPENTER, F. B., Types of tobacco and their analyses North Carolina
State Agric. Exper. Bull. no. 122. 1895.
4- GARNER, W. W., Th Se are OR Mae ee
qualities of tobacco. Baloo. BaP nd US Dept. Agric.
5. Hoser, M. R., Ph Gewebe. Leip
und Berlin. 1914. i . oe
6. Jenkins, E. H., Experi ir with different fertilizers.
Ann. Rep. Conn. State Agric. Poy Sta. rugs 1895.
7. Kisstinc, RicHarp, Die Chemie des Tabaks. Chem. Zeit. 8: 68. 1884. 7
ie cc ee es aie
NOTES ON NEW OR RARE SPECIES OF RAVENELIA
W. H. Lone
While on recent field work in Texas, the writer collected several
very interesting species of Ravenelia. Some of them are unde-
scribed, while others have heretofore been known only from their
type collections. Several of them are Mexican, while one is a
South American species.
Ravenelia hoffmanseggiae, sp. nov.
O. Pycnia unknown.
Il. Uredinia amphigenous, scattered, orbicular to irregularly
oval, liver brown,’ subepidermal, ruptured epidermis prominent;
paraphyses none; urediniospores obovate, ellipsoid to subglobose,
16-25 by 25-30, average for 10 spores 19.7 by 26.7, walls —
thin, 1-1.5 w, uniform in thickness and concolorous, capucine buff
in color, sparsely and minutely echinulate when dry but appearing
as if smooth when wet; germ pores 8, situated in two irregular —
rows of 4 each, one row subequatorial, the other near apex of spore,
ee -
Ii Telia unknown.
se On Cassiaceae. Ty Nected oa Hoffmoniers! taps at Del 1 Rio, :
‘Texas, November 6, ion 6, by W. Doce 6082)? This isthe ist cole.
tion « fmanseggia
is widely distributed throughout those “regions where species of Rasenelia
flourish
58 BOTANICAL GAZETTE [JULY
urediniospores obovate, obovate-elliptical to subpyriform, 15-18
_ by 25-37 », average for 20 spores 16.9 by 31.7 u, walls ochraceous-
tawny, concolorous, thick, 2.5-3.5 4, apex but slightly if at all
thickened, echinulate; germ pores prominent, 6 in equator.
III. Telia amphigenous, usually epiphyllous, sparse, scattered,
small, o.1-0.5 mm. across, bullate to elliptical, subcuticular,
blackish-brown, tardily naked, ruptured cuticle very conspicuous;
paraphyses none; teliospore heads chestnut-brown, subglobose,
40-60 p in diameter, average for 20 heads 50.5 u, 2-4 spores across,
5-10 spores to each head, 4-8 marginal, o-3 inner spores, usual
number of spores per head 7-8, each spore bearing 3-6 short hydline
tubercles 3-5 4 long; cysts few, 4-8, as many as the marginal
spores, subglobose, subpendant around pedicel, not cohering,
easily. swelling and bursting in water; pedicel hyaline, short,
—— compound.
On Mimosaceae. Type collected on Siderocarpos flexicaulis 6 ‘alien from
Brownsville, near Tandy’s Switch, Texas, November 11, 1916, by W. H. Long
_ (no. 6174). This Ravenelia is very abundant on this heat 4 in the Texas ebony
jungles in the immediate vicinity of Brownsville. It is probably common
wherever its host is found i in sufficient quantity to form thickets.
Ravenelia prosopiis, sp. nov.
oO.
‘IL, Uredinia sparse in material examined, small, amphigenous,
‘ead ealylow, often in a circle around a central sorus, 0. 5—-
-_y.9mm. across, narrowly elliptical to , subepidermal, long
| covered by the epidermis, ruptured ad very prominent;
___ urediniospores oval to subpyriform, 13-20 by 24-41 p, strontium
: lla eae for 40 spores, 16. one S had walls: I. 5-2 u thick,
oe 4-6 in equ ¢ ua tor; paraphyses abu aed dan t, of two ape, ia deal pane :
a capitate, the ae Saane clavate, ina Sense bane around the i :
1917] LONG—RAVENELIA 59
.
elliptical to oval, subepidermal, early naked, ruptured epidermis
very prominent; teliospore-heads tawny, depressed hemispherical,
often concave at top, 75-118 uw, average for 40 heads 94 p, 6-10
spores across, 20-28 marginal spores, 16-40 inner spores, usual
number for head 46-54 spores in all; heads papillate, with one,
rarely two, papillae to each spore, papillae ranging from mere
tubercles near top of head to blunt papillae 4-7 yw long around
margin, top of heads often free from papillae, many heads with
only a few tubercles on entire head, papillae light brown;
paraphyses very abundant in a dense circle around the telia, also
scattered throughout the sorus, similar to those found in the ure-
dinia, often sori occur which are composed mainly of paraphyses;
cysts numerous, pendant in 2 or 3 rows around the pedicel, sub-
globose, about as many as marginal spores, easily swelling and
bursting in water; pedicel coats etoanit, deciduous, —_ to faintly
fulvous, short.
On Mimosaceae. Type collected on Prosopis Jaitors at Denton, tenis,
October 10, 1907, by W. H. Long (no. 2013); a same host
and in same locality in 1908 by Long (no. 4870). Ack the type material
of this Ravenelia was issued in Fungi ncmaseane Ee exraccoienn, no. 2681, _
as Ravenelia arizonica Ellis and Ev. —
Ravenelia prosopidis is closely related to R. arisonica, but differs from this
zonica. "alk peciee wal postal bs lens
the range of its host. It is sometimes associat
Neoravenelia avenelia holwayi, at least some telia were found which conta Lo
: spores with be iy eth wie her end alee oc cota oe
5 : os (nos. 6145 and 6148).
60 BOTANICAL GAZETTE [JULY
brooms, often densely confluent on both sides of the pods over
areas I-5cm. across, individual uredinia on pods elliptical to
irregularly oval, o.2-0.6 mm. across, verona brown to tawny-olive
in color, uredinia on leaves amphigenous, elliptical to irregularly
oval, primary uredinia often encircling pycnia; urediniospores
obovate-oblong to linear-oblong, on pods 10-17 by 27-45 mu, average
for 20 spores 13 by 31 u, on leaves urediniospores are 10-14 by
27-38, average for 20 spores 13 by 33 p, average for both sets of
spores 13 by 32u; walls 1-1.5y thick, slightly thicker above
(about 3), prominently but sparsely echinulate, spinules very
sparse on upper third of spore, upper third golden brown to wine
color, remainder of spore paler to hyaline, germ pores 8, in 2 rows
of 4 each, upper row at boundary of colored and hyaline part of
spore, lower row about the same distance below the equator;
paraphyses abundant, intermixed with the urediniospores, clavate
to clavate-capitate, 35-50 u long, average length for 10, 44.0n,
heads 9-13 uw, average for 10 heads toy, apex of head thickened
about 3 », pale fulvous, stipe usually thin-walled, hyaline.
III. Telia amphigenous, often abundant on all parts of badly
infected leaves, scattered, subcuticular, blackish, shining, o.2-
1.2mm. across, irregularly oval, ruptured cuticle noticeable;
_ teliospore heads blackish, 63-100 uw, average for 30 heads 78 un,
5-7 cells across, 14-30 spores in each head, 8-14 marginal spores
and 6-15 inner ones, verrucose, each spore bearing 3-10 colorless
warts about 2 u tall by 3 » broad; paraphyses present and similar
to those in uredinia; cysts of same number as marginal spores,
flattened, appressed beneath head, extending from periphery to
_ pedicel, in one row, united laterally, ovoid to oblong-ovate, slow
to burst in water; pedicel short, colorless, compound, deciduous.
: DISTRIBUTION.—TEXAS: On Acacio roemeriana, San Marcos (type local-
as ity), poy in . November TOTS (nos. 5494 and 5498 type), i in May 1916 (nos.
6909, 6019, 6020, and 6065); San Antonio, Long, in May 1916 (nos. 5610,
— 5611, 5612, 5614, and 5615), 08} in | November aie es. 6155 and 6159);
Uvalde, Heald and Wolf, :
deride ——! —_ merianae ww tte lee wt cacia iit emerian: pe
1917] LONG—RAVENELIA 61
visited the type locality of this rust at San Marcos and found an abundance
of uredinia, especially on the pods. Some uredinia as well as pycnia were also
found on the leaves. Even at that early date telia were developing and the
uredinia on the leaves were disappearing. The uredinia which were so abun-
dant on the pods in May weathered and disappeared so that none were found
on the pods in November of the same year.
The writer has seen several thousand trees of Acacia roemeriana infected
with this Ravenelia in various places in Texas, and only two trees of this entire
number showed any evidence of witches’ brooms. One tree was found at
San Antonio and the other at Uvalde, Texas. There were some 1o-15 witches’
brooms on each of these two trees. Apparently the germination of the telio-
spores of this rust occurs when the pods are young and easily infected and yet
not at the right season to infect the young branches and cause witches’ brooms.
This rust is closely related to Ravenelia versatilis (Peck) Dietel, a vie noted
in a previous article’ by the writer. TableIg more —
salient characters of each of these two species of Ravenelia. From this table
the main differences between the two species are easily seen
Ravenelia roemerianae has been collected by the crits a several places
in Texas and probably occurs wherever the host is present. The rust was
exceedingly abundant in the vicinity of Uvalde, Texas, in November 1916.
Every tree of Acacia roemeriana examined by the writer in the mesquite
Presepis juliflora)-catclaw (Acacia roemeriana) flats was heavily infected; in
‘leaf on most of the trees was practically covered with the blackish
telia of this rust.
RAVENELIA MESILLANA Ellis and Barth. Bull. Torr. Bot. Club_
251508. 1898 * :
(Ravenelia lensiona Sydow, Hedwigia Beibl. ak Toor).
O. Pycnia, appearing before the uredinia, sparse, amphige-
nous, in circinating, crowded, orbicular groups | :
subcuticular, Brussels brown, ——- hemispherical, 40-60
iat a wR geceests 7
. Uredinia am
tawny, oval to elliptical, °. s-1. chon sinty Juve aay ket pe ao
_ verulent, subcuticular, ruptured cuticle very noticeable; uredinio-
- Spores oval to subglobose, 15-22 by 20-26 u, ee a -
SF 19 J 23 oe thick, oo !
¥
aBeiont ‘s 06-55
BOTANICAL GAZETTE
ISOINLIIA SPBIY
yeursivur ‘nf gl
advaaar ‘Wf oo1-£9
spray BHT,
6
1917] - LONG—RAVENELIA 63
the spores, colorless, clavate to subcapitate, 5-14 by 35-62 y,
average for 20, 9.6 by 45 u, apex of head thin-walled, base of head
very thick-walled, stipe usually solid.
III. Telia amphigenous, scattered, o.5—1.0 mm. across, often
confluent over areas 3-4 mm. in diameter, brownish-black, elliptical
to irregularly oval, subcuticular, ruptured cuticle very conspicuous;
teliospore heads dark chestnut-brown, hemispherical, smooth or
an occasional head with a few scattered, short (2-3 u), hyaline,
tubercles, especially on the marginal spores, 5-9 cells across, 60-
gO w, average for 20 heads 74 uw, 10-20 marginal spores, 8-24 inner
spores, usual number per head 24-32; paraphyses present but very
few and similar in every way to those found in the uredinia; cysts
hyaline, in 2-3 rows around the pedicel, many, not coherent with
each other, slow to burst in water, subpendant; penis colorless,
compound, short, deciduous.
This description of the rust was drawn from
+ Distripution.—New Mexico: On Cassia bauhinioides, “Mesilla Park,
Wooton, in October 1895, ex. Herb. N.Y. Bot. Garden (no. 5021 Long) and
ex. Herb. A. and M. College of N. Mex. (no. 5022 Long); Wooton in October
i. North American Fungi, Herb. of ELam BaRTHOLOMEW (part of ty
= re See
August 1901 and October 1915 faa 1019 and tan: Llano, ne ead Wolf,
1909 (no. 1751 Herb. Path. and ; Myc. Investigat., Plant Disease Sur- oe
and
vey); Marble Falls, Carsner and Studhalter, May 1912 (no. 4333 Herb. Univ.
Texas); Meridian, Long, June 1916 (no. 6056); San Antonio, Long, May and —
November 1916 (nos. 5616 and ots San Marcos, i November 1915, and
May 1916 (nos. 5468 and 6034).
This &. Cacsia ba SEES ee at Mesilla rk
| New Mexico, in 1895 and aanin in 1897 “ee Wooton. It was described as a a
ae
lected in 1897. Tt has been reported on
a In 1900, ~ writer sent $
. Austin, T:
64 BOTANICAL GAZETTE [JULY
while R. longiana had a few hyaline ones. The writer has material from the
type collections of both of these species, and a careful examination of this
material shows that not only do both species have paraphyses, but that the
paraphyses are identical in every respect and are present in the telia of the type
material of both R. mesillana and R. longiana. A careful study of the other
salient characters of these rusts has convinced the writer that they are identical
in every respect and therefore should be considered as only one species
In recent field work in Texas, the writer collected the pycnidial stage on
Cassia roemeriana of what has heretofore been known as Ravenelia longiana.
RAVENELIA SILIQUAE Long
O. Pycnia unknown.
II. Uredinia hypophyllous and caulicolous, on the leaves
scattered, elliptical, o. 5—1.o mm. across, pulverulent, subcuticular,
early naked, sudan brown, ruptured cuticle not prominent, uredinia
on the woody twigs and branches perennial, very inconspicuous,
elliptical, o.5-5 mm. long by o.5-2 mm. broad; urediniospores
obovate, elliptical to rarely oblong, on the leaves 13-17 by 20-27 u,
average for 10 spores 14.4 by 21, urediniospores on branches
11-16 by 17-27 m, average for 20 spores 13.4 by 22.5 uw, uredinio-
spores on both leaves and branches buff yellow; walls 1.5-2.5 4
thick, concolorous, not thickened at apex, densely and strongly ver-
-Tucose, germ pores 8, in two transverse zones of four each, equidis-
tant from the equator; paraphyses abundant, intermixed with the
spores, clavate to subcapitate, often curved, 7-10 by 50-67 yn,
average for 10 paraphyses 9.5 by 62u, heads pale fulvous to
hyaline, stipe slender, usually solid, hyaline, paraphyses in sori on
woody branches few, 6-11 by 25-49 uw, average for 20 paraphyses
8.3 by 38u. :
— ML tela unknown.
a On Mimosaceae: Distributed ; as follows: Tern, on ae ine
San Antonio, Long, November 1916 (no. 6153); W. H. Mercer, February 1917
a (no. 6263); _— on Acacia farnesiana, Etla, Oaxaca, Holway, October
1899, no. 3841 of | Holway (type); Hawaii, on jrempaies farnesiana, Honolulu, ;
o Hora ze Lyon, jou. 1013, ae 164, 4, SyDo’
= 3 aston he pd of thos fom Haw ares eye ith the :
«
1917] LONG—RAVENELIA 65
on the pods of Acacia farnesiana from Mexico, the rust has been collected in
Texas on the leaves and woody branches of this host and in Hawaii on the
It was probably introduced into Hawaii on nursery stock which con-
tained infected woody branches. Apparently Ravenelia siliquae does not have
a telial stage, since only uredinia have ever been found, although this rust has
been collected during October, November, January, and February on pods,
leaves, and woody — and in three countries, namely, United States,
Mexico, and Hawa
RAVENELIA AUSTRALIS Diet. and Neg.
O. Pycnia unknown.
II. Uredinia amphigenous, very small, punctiform to irregularly
oval, less than 0.5 mm. across, subepidermal, soon naked, rup-
tured epidermis inconspicuous; urediniospores obovate, elliptic-
obovate to subpyriform, light cinnamon brown, 13~20 by 25-32 yu,
average for 20 spores 16.6 by 28.2y; walls 1.5-2.0p thick,
slightly or not at all thickened above, concolorous, echinulate,
germ pores 4—6, equatorial; paraphyses very abundant, incurved,
dense, encircling the sori, ferruginous, hyphoid, more or less curved
near apex, 10-17 by 50-67 w, average for 10 paraphyses 12.5 by
14.4 mu, walls about 2.5 w thick, an occasional paraphysis clavate,
nearly colorless and with a solid stipe.
Tlf. Telia amphigenous, punctiform to irregularly oval, less
than o.5 mm. across, blackish-brown, subepidermal, early naked,
ruptured epidermis inconspicuous; -paraphyses very — :
encircling the sori and similar to those found in the u
teliospore heads chestnut-brown, hemispherical, 67-110 w across,
average for 20 heads 92.3 u, 7-11 cells across, 18-30 marginal ~
ee 22-64 immer ones, 40-94 ‘spores pet head, smooth; cysts
1, beneath entire head, i Mu,
66 BOTANICAL GAZETTE (yur
The writer has not been able to obtain authentic material of this South Ameri-
can Ravenelia, nevertheless he is assigning to this species the Texas Ravenelia
collected on the same host (A. farnesiana), since its characters are practically
identical with those described for the South American plant.
RAVENELIA GRACILIS Arth.
O. Pycnia not found in the Texas material.
II. Uredinia epiphyllous, seated on slightly pallid areas, scat-
tered, very small, less than o.4 mm. across, elliptical to irregularly
oval, tardily naked, subepidermal, ruptured epidermis promi-
nent; urediniospores ovate, ovate-fusiform to somewhat flask-
shaped, usual shape ovate-flask-shaped, 15-21 by 30-45 mu, average
for 20 spores 18.4 by 37.6; walls 2-2.5 uw thick, russet colored,
sparingly echinulate, apex darker and slightly thickened, germ
pores 4-6, in equator; paraphyses few, peripheral and also inter-
mixed with the spores, hyphoid to subclavate, hyaline, walls thin,
4-7 by 35-50 n
Ill. Telia ection: similar in size and shape to the uredinia,
blackish-brown, subepidermal; teliospore heads dark chestnut-
brown, hemispherical, 60-87 by 37—40 yw thick, average for 20 heads
73.8 by 39 wu, 5-6 spores across, 8-14 marginal spores, 4-12 inner
spores, usual number per head 22-24, each spore on lower part
of head bearing 2-4 small, hyaline tubercles, 2-5 » long, upper
: portion smooth, or with 1-4 very short tubercles to each spore; _
_ cysts in 1 row, subglobose, few, as many as the marginal spores,
united laterally and extending from periphery to stipe, sub-
appressed, easily swelling and ome in ee; pedicel short,
deciduous, colorless. — |
ay Collected on Havardia brevifolias 6 miles from Brownsville, Texas, neat
ave Pagans: November 10, 1916, by W. 4. Long | ae 6160). ‘Thndoce
lyr Ff: ee te > cdliection which 4
S; Mexico, on an unknown host. Ts .
Texas, ions le sin to be the same - a
1917] LONG—RAVENELIA 67
host and of the host found at Brownsville shows that the two are apparently
identical. Ravenelia gracilis was —— common i in the vicinity o of B rownsville
this species the urediniospores are given as obovate and the teliospore heads
as bearing 4~-7 colorless tubercles to each spore. The writer, however, failed
to find any obovate urediniospores in that portion of the type collection which
is in his herbarium. The teliospore heads of the type show many heads with
smooth tops but with short tubercles around the margin, while other heads in
the same mount have shorter and fewer warts to each spore at the top than on
the margin, thus agreeing in every detail with the Brownsville material.
RAVENELIA LEUCAENAE Long
This species was collected by the writer near Brownsville, Texas,
on Leucaena pulverulenta. There are certain minor characters of
this rust not given in the published description of it that are worth
_ recording. The urediniospores on this host are mainly concolorous,
often with the apex slightly thickened. The teliospore heads are
5-6 cells across, with 5-16 marginal spores and 3~14 inner ones,
usual size 14-16 spores per head, each spore at top of head bears
from o to 2-4 very short tubercles, while there are 4-6 Lome or
slightly curved tubercles, 4-64 long, on each spo.
cysts as many as marginal spores, agen extending ee
fie po Ae cae
This DR, =’ t rt 1) pee aten tlk = + warn,
Lencsna sp. diversi, and L. esculenta.
NEORAVENELIA HOLWAYI ‘Wietel) Long =
II. Uredinia caulicolous, forming large, woody, perennial, fusi-
form galls, 1-8 cm. thick A 4-12 cm. long, ceed —— over
large areas oe ae galls, argus brown - spor
_ oblong-linear, obovate, ¢ elliptical, clavate to subp sib :
oe shape obovate to si clavate, 13-24 by eage eel for 120 |
Spores 7 by 36 ms ie eee: = ck, slig , ed :
68 BOTANICAL GAZETTE [JULY
III. Teliospores intermixed in uredinia on the galls; teliospore
heads liver brown, hemispherical, often depressed, smooth, 60-
130, average for 40 heads 103m, 8-12 spores across, 20-38
marginal spores, 40-78 inner ones, average number of spores in
each head 84-94; cysts globose to subglobose, in 2-3 rows, pendant
beneath entire head, not coherent, slow to burst in water; pedicel
hyaline or slightly tinted, short, deciduous, compound. This is
a description of the gall-producing form of Neoravenelia holwayi.
For several years the writer has been finding a species of Ravenelia on
mesquite (Prosopis juliflora) which produces large, fusiform, woody galls. At
first this rust was referred to Rovenclia ari ee, oe + careful examination of
the gall led tl These smooth
teliospores were so constantly Souké Sasictataid with certain types of galls that
the writer made a special study of the galls found on mesquite. This investi-
gation showed that there was a Ravenelia present on galls throughout a certain
zone which constantly produced smooth teliospore heads. A careful study of
the Ravenelia on these galls failed to show any positive differences either in the
urediniospores or teliospores which would separate this gall-forming species
from the ordinary leaf form of Neoravenelia holwayi. There are wide variations
in shape and size of the urediniospores, as is to be expected when one oF
galls as compared to those found on the leaves.
The galls were found in localities where the leaves of the mesquite were
abundantly infected with the usual form of N. kolwayi. In the vicinity of
_ San Antonio and Uvalde the galls were rare, but at Corpus Christi and Browns-
ville they were rather common. From Del Rio west to New Mexico and
Arizona all of the galls found « ite were of a different type and were
associated with the ti ues a of Desaulia arizonica. The galls produced by
Neoravenelia holwayi are smoother and more fusiform than those caused by
Renae Seen, in R: arizonica the galls are rather brittle, due to the
larg yma i pe d in the gall vac ereennaanger
when alive these galls have deep transverse fissures in their surfaces.
which are borne the soliedaees and idicepoces. But few sori of any kind
re were found on galls collected as late as November. The surface of the galls
- baoph ater gendinie gis tacciie Se
; telio
1917] _ LONG—RAVENELIA 69
would be an undescribed species. As it now stands, this species parallels
Ravenelia arizonica, both species having a leaf and a gall form; the galls of
each usually bear only urediniospores, while teliospores are rarely found on the
galls but usually occur on the leaves.
Type material of each of the 3 new species of tae sho described
in this paper has been deposited in the Pathological and Mycologi-
cal Collections of the Bureau of Plant lednstyy: Department of
Agriculture, Washington, D.C.
OFFICE OF INVESTIGATIONS IN
t PATHOLOGY
. : : : no knowledge of this put ee til j oS
ARBORES FRUTICESQUE CHINENSES NOVI. ITI’
CAMILLO SCHNEIDER
Cotoneaster (Sect. CHAENOPETALUM Koeh.) oligocarpa, n.sp.—
Frutex latus, erectus, ad 4 m. altus; ramuli hornotini initio to-
mento villosulo flavescenti-cinereo adpresso obtecti, annotini satis
glabrescentes, fusco-rubri, vetustiores glabri, plus minusve cineras-
centes. Folia subcoriacea, partim persistentia, ovalia, obovato-
elliptica vel praesertim versus apicem ramulorum ovata (in
specimine florenti distinctius obovata), apice acuta et mucronulata
vel satis obtusa et interdum subrotundata, basi pleraque late
cuneata, 2.5—-5 cm. longa et 1.2—-2.5 cm. lata, superne saturate,
sed ut videtur obscure, viridia, initio laxe villosula, biennia costa
impressa excepta glabra, subtus modo ramulorum novellorum
dense tomentosa, etiam adulta haud vel tantum in costa elevata
_paullo glabrescentia, in facie sub microscopio papillis distinctis
= ee, nervis coments superne plus minusve impressis
insecus 8—12; petioli dense tomentosi,
_vix ultra 6 mm. longi; stipulae triangulari-lanceolatae, acuminatae,
petiolis breviores, subtus dense tomentosae, superne glabriores.
Corymbus satis densus, multiflorus, ad 4 cm. (vel ultra ?) latus
et ad 3.5 cm. altus, villosus, bracteis bracteolisque deciduis sub-
ulatis circ. 3 mm. longis; pedicelli 1-3 mm. longi, ut
villosi; flores albi; receptaculum ovato-turbinatum ut sepala Lite
triangularia circ. 1-1.5 mm. longa apice glanduloso-mucronulata
ints giabes, eae eee foneteahen, ad 2.5 mm. longum;
Th L en ae
‘ thunk Af ‘¢hia ornicok: me Mabenia ia proposed
by me in the previous paper (Bor. Gaz. 63: Ԥ19-521. r917) have been described by
‘pass Males” (Sor Rey. Bet. Gand. Basbege sok - Old World species of the
BA, nos 20, 9° Janmary 1082). —
tic wes
2 te same as M. rade Takeda owe
rh nsis. von omy eb edt
rere by TAREDA to ib new M. I
that: the two s
1917} SCHNEIDER—NEW CHINESE PLANTS Ce |
petala orbicularia, circ. 2.5 mm. lata, basi unguiculata, intus
pilosula; stamina 20, petalis paullo breviora, antheris ut videtur
violaceis; carpidia 2, apice sparse villosa, stylis quam stamina
fere longioribus stigmatibus capitatis planis. Fructus parvi,
rubri; subglabri vel satis villosuli, plus minusve turbinati, 4-5 mm.
longi, apice circ. 3 mm. crassi, sepalis extus villosulis incumbentibus
fere clausi; pyrenia 2, obcordato-ovoidea, circ. 3.5 mm. longa et
infra medium 2.5-3 mm. lata, stylum in apice vel paullo infra
gerentia, ventre leviter carinata, subnitentia, dorso paullo sulcata,
basi hypostylii leviter constricta, hypostylio circ. trientem dorsi
occupante villosulo.
Yunnan boreali-occidentalis: in dumetis ad vias inter Ho-ching et Li-
chiang-fu, alt. circ. 2600 m., 25 Septembris 1914, C. Schneider (no. 77
typus in Herb. Arb. Arn. et Hb. Schneider).—Szechuan australis: ad vias
declivibus montium prope Wo-lo-ho, alt. circ. 2800 m., 13 Junii 1914, C
watis).
glabrescen
ieee ippatiie. Cc salicifolia var. rugosa R. and W. and var. floccosa R.
and W. differ by the same characters of the leaves and by their larger more
subglobose fruits. Its nearest relative may be C. Harrowiana Wils., of which
‘have not yet seen the fruit; but the old leaves :
glabrescent beneath. Having introduced C. ‘oligocarpa into cultivation, cs
has to be decided by observation of li; gc
or only a variety of C. Horrewiana which comes from southern Yanna.
C witdais dad ta ection ©. Harrowiana and C. oligocarpa
a group of very closely related which may So iced ace a
oo ee ee :
on the under surface, — of suntan the — fo Lae
72 BOTANICAL GAZETTE [JULY
tantum in costa impressa pilosa, facie plana sed tenuissime reticu-
lata nervis non incisis, subtus dense ut ramuli tomentosa, etiam
biennia tantum in costa prominente paullo glabrescentia, nervis
lateralibus utrinsecus 5-7 vix vel paullo prominulis; petioli vix ad
5 mm. longi, dense tomentelli; stipulae anguste triangulari-lanceo-
latae, acuminatae, petiolis breviores, subglabriores. Corymbus
pluriflorus, ad 3 cm. latus et 2.5 cm. longus, dense villoso-tomento-
sus; pedicelli 1-2 mm. longi, ut pedunculi tomentelli, bracteis
bracteolisque deciduis; flores ignoti; fructus parvi, obscure rubri,
turbinati vel globoso-turbinati, circ. 4 mm. longi et 3 mm. crassi,
plus minusve villosuli, apice sepalis incumbentibus extus villosis
fere clausi; pyrenia 2, circ. 3 mm. longa et 2.5 mm. lata, obovoidea,
ventre plana, satis laevia, nitidula, dorso leviter rugulosa, stylum
apice gerentia, hypostylio circ. trientem dorsi occupante villosulo.
Yunnan boreali-occidentalis: ad latera orientalia montium niveorum
prope Lichiang-fu, alt. circ. 3000-3200 m., Octobri 1914, C. Schneider (no.
2676; typus in Herb. Arb. Arn. et Hb. Schneider).
The fruits of this species are extremely like those of C. oligocarpa Schn.,
previously described, but in its narrow elliptic obtuse leaves, which are smooth
above and show very little prominent veins beneath, C. Vernae differs widely
from all the species mentioned above. It seems to be more closely related to
C. pannosa Fr. which, however, can easily be distinguished by its more ovate
acute or shortly acuminate leaves, and by its larger fruits, the sepals of w
are more erect. Iam unable to identify my no. 2676 with any Chinese species
hitherto described. I introduced it into pmiahinrrete (seed | no. 578); and —
vations of living plants may give further indications of
this apparently well marked species. It is named for my daughter Verna.
PRUNUS LATIDENTATA Koeh., var. trichostema, n.var.—
_P. trichostoma Koehne in Sargent, Pl. Wils. x: 216. 1912.—A
typo non nisi — intus et stylis basi distinctius — differre
videtur. ;
: - Szechuan australis: ‘in regione Yen-yiian fies, inter ‘vedes Ka-la-pa
et Liu-ku, i in sepibus, alt. circ. 3200 m., 17 Maji ror4, C. Schneider (no. 1210;
_ frutex ad 2 m. altus); inter viculos Hun-ka et Wo-lo-ho, alt. circ. 3300 m.,
13 june 1914, Cc. Schneider (no. 3520; arbuscula vel arbor ad Gémalta).
cording own statement, there is really no other difference —
| Detween P.laidenat nba sand P.ichastoma than the vabsionece lai the eal ao
So far as I can j s bef : : De
1917] SCHNEIDER—NEW CHINESE PLANTS 73
POTENTILLA ERIOCARPA Wall., var. cathayana, var. nov.—
? P. eriocarpa Franchet, Pl. Delav. 211. 1889, non Wall., sensu
Lehmann et Wolf; Diels in Not. Bot. Gard. Edinbgh. 7: 157.
1912, 387. 1913.—A typo a cl. Lehmanno depicto recedit foliolis
omnibus sessilibus, inflorescentiis ad 3-floris, sepalis externis ovato-
lanceolatis subacuminatis quam interna paullo latiora saepe dis-
tinctius acuminata vix vel paullo brevioribus.
Yunnan boreali-occidentalis: in fauce infra glaciem parvam montium
niveorum prope Lichiang-fu, in rupestribus calcareis, alt. circ. 3900 m., 17
Augustii 1914, C. Schneider (no. 2274; typus in Herb. Arn. Arb. et Hb. Schnei-
der; suffrutex floribus magnis luteis, ramulis floriferis 5-15 cm. altis).
According to the figure given by LEHMANN and to WoLr’s description,
the typical P. eriocarpa Wall. has “sepala externa late elliptica obtusa vel
rotundata,”’ and the leaflets are described as “plus minusve longe petiolulata
(saltem terminale)?’ The petals of var. cathayana seem also to be much more
emarginate than those of the type.
Rubus (Subgen. Iparosatus Focke, sect. IDAEANTHI Focke)
testaceus, n.sp.—Frutex habitu R. Jdaei ad 1.5 m. altus, dumeta
formans; rami vetustiores teretes, aculeis paucis aculeolis sparsis
vel crebris rectis armati, satis dense villosuli et glanduloso-setulosi,
setulis intermixtis, partim glabrescentes et testacei; ramuli floriferi —
ut videtur nondum satis evoluti ad 10 cm. longi, cum petiolis
pedicellisque densius griseo-villosuli et etiam glanduliferi et parce
setulosi. Folia visa omnia ternata; foliola ovato-rhomboidea vel
rhomboideo-orbicularia, iis R. schizostyli ex icone a cl. Focke in
monogr. p. 206 dato satis similia, terminalia petiolo ad 1 cm. longo ©
suffulta, maxima visa ad 3.5 cm. longa et 3 cm. lata, apice rotun-
data, obtusa (vel rarius in foliolis satis juvenilibus oblongioribus
_ subacuta), lateralia subsessilia, ad 1.8 cm. longa et 1.5 cm. lata,
omnia subaequaliter satis grosse dentata vel inaequaliter dentato- _
_ Serrata, sublobulata, _Superne- satis flavo-viridis, laxe vel initio
7
‘ os glabriuscula, in costa. ‘nervisque lateralibus oteaade 7 G-)
Q ce & ek hirta_ et pe minusve e gland ul losa 5 petioli ad > cm. longi; | -
vesert op extus m villoate ee tae
74 BOTANICAL GAZETTE _ [jury
bractea stipulis simillima instructi; calyx externe modo pedicellorum
villosulus, glanduliferus et parcissime setulosus, sepalis lanceolatis
acuminatis margine albo-villosis circ. 7 mm: longis patentibus
intus basi glabrioribus; petala oblonga vel satis anguste obovato-
oblonga, versus apicem acutiusculam undulato-marginata, basim
versus longe cuneata, intus sparse pilosa, demum ut videtur
patentia, sepalis subaequilonga et ultra medium circ. 3-3.5 cm
lata; stamina in flore ut videtur erecto-patentia, circ. 70-75,
filamentis glabris longioribus petalis subaequilongis; carpophorum
pilosum; carpidia circ. 30, 4.5+5 mm. longa, stylis glabris, ovariis
ima basi pilosis et dorso saa parcis praeditis; discus glaber.
Fructus ignoti.
Szechuan australis: in regione Yen-yiian Hsien, inter viculos Ka-la-pa
et Liu-ku, alt. circ. 3500 m., 17 Maji 1914, C. Schneider (no. 1269; frutex ad
1.4 m. altus, dumeta formans, foliis valde juvenilibus); eodem regione, ad
viam inter Liu-ku et Kua-pie, alt. circ. 2800 m., 19 Maji 1914, C. Schneider
= 1213; flores rubri).—Yunnan bores ooctdentatis: in regione Yung-ning,
us pagum Mu-ti-chin, alt. circ. 2800 m., 23 Junii 1914, C. Schneider (no.
stn typus in Herb. Arb. Arn. et Hb. Schuasiden).
Judging by the shape of the leaves, this species seems to be very similar
to R. schizostylus Lév., which I know only from the figure given by Focke in
his Mon. Gen. Rubi Prodr. in Bibl. Bot. 72: 206. fig. 83. 1911; but according
digo acts, ner poadeiaie clean cea cagehinn ee having
. foli pilis
adpressis albis.”” R. cima Packs: Le. 204. fig. By ak
and Szechuan, has white or pink flowers, and is otherwise extremely different.
Another species to which R. festaceus may be related is R. kanayamensis Lév.
and Van. in Bull. Soc. Bot. France 53: 549. 1906 et apud Focke, l.c. 205,
from Japan, of which the leaves are described as “in utraque angular: et
_ parce pilosa,” but it has an “inflorescentia laxe effusa,” and, according to
- Focxe’s statement, “revocat R. id. subspec. strigosum,” he shape of the
leaves of which is entirely different ee
zles tothe pale brick red color ofthe older serge cage hes.
Ate false, Se. | ee
ee 6-jugis,
tg17]} SCHNEIDER—NEW CHINESE PLANTS . 75
pedicelli ad 18 mm. longi, plus minusve tomentelli, apice excepto
non incrassati.
Yunnan boreali-occidentalis: in declivibus herbosis calcareis montium
Tsang prope Tali-fu, alt. circ. 2800 m., Augusto 1914, C. Schneider (no. 2526;
typus in Herb. Arb. Arn. et Hb. Schneider).
This variety agrees well with typical R. Mairei Lév. except that the leaves
have 5-6 pairs of leaflets instead of only 2-4 pairs. Unfortunately the fruits
of the type are still unknown. ReEHDER.and Witson in Sargent, Pl. Wils.
2: 344. 1915, say that R. Mairei “is probably nothing more than a very
hairy and small-leaved variety of R.. omeiensis Rolfe.” In my opinion, it
seems much more closely related to R. sericea Ldl. which, however, comes very
near R. omeiensis. The new variety may be identical with the true R. sericea,
f. pteracantha Franchet in Pl. Del. 220. 1889=R. sericea Crépin in Bull.
Soc. Roy. Bot. Belg. 25: 9. 1886, ex parte, quoad no. 861 Delavayi, which
he describes as having “folia majuscula utraque facie sericeo-tomentella, ”
‘but he does not mention the number of the leaflets neither does CREPIN.
pteracantha in Gard. Chron. III. 28: 260. figs. 98, 99, 1905; and in Bot..
Mag. 134: pl. 8228. 10908, which is the same as R. omeiensis f. pteracantha
R. at W. in Sarg., Pl. Wils. 2: 332. 1915.
he typical R. omeiensis Rolfe is well characterized by its OP ee eaten
SE the leaflets of which are entirely glabrous or hairy only on the
beneath, and by the distinctly thickened and colored (yellow or red) footstalks
of the ripe fruits (see Bot. Mag. 138: pl. 8471. 1912) ; but there are certain —
hairy forms with almost subsessile fruits and f ewer leaflets which come very
near to R. Mairei as well as to R. sericea. The type of R. sericea as represented
by Liypiey in his Rosac. Monogr. 195. pl. 12. a has 7-1r leaflets which
le revétement de ses axes et de ses feuilles.”” ‘By Wusox, Foazsst, and my-
self many forms have been it into culti so
: able to judge the value of the different characters p _
fruits, ar ai “ais RIE
76 BOTANICAL GAZETTE [JULY
vel breviter acuta, basi plus minusve rotundata, rarius late cuneata,
lateralia inferiora minora (13—) 15-22 mm. longa, (8-) 10-15 mm.
lata, superiora majora ad 3.2 cm. magna, terminalia superioribus
plus minusve aequalia sed saepe paullo latiora, margine dupliciter
inaequaliter glanduloso-serrata (sublobulata) dentibus majoribus
mucronulatis porrectis dorso denticulas 1-3 gerentibus, superne
viridia, in sicco leviter glaucescentia, laevia, glabra (interdum
sparsissime glanduloso-pilosa), subtus viridescentia, dicoloria,
in costa et etiam partim in nervis lateralibus utrinsecus 5—8 paullo
prominulis satis rectis plus minusve pilosa et etiam ut in facie
pilis glanduliferis crebris conspersa (oculo nudo quasi nigro-
punctata), rete nervillorum subvisibili; petioli 2-3.5 cm. longi,
ut rhachis plus minusve dense villosuli, stipitato-glandulosi et setis
aculeolisque sparsis muniti; stipulae satis evolutae, ad medium
adnatae, 10-13 mm. longae, auriculis latis acuminatis, margine
dense glanduloso-ciliatae, ceterum ut folia pilosa et glandulifera.
Flores kermesini, stiaveolentes, circ. 3 cm. diametientes, solitarii
vel 2-3 apice ramulorum ad 8 cm. longorum terminales; pedicelli
10-12 mm. longi, basi bracteis ovatis vel late ovatis apice subito
acuminatis ad 12 mm. longis et 8-9 mm. latis dense glanduloso-
ciliatis suffulti, glabri, interdum fere nudi sed plerique crebre
stipitato-glandulosi; receptaculum ellipsoideo-oblongum, glabrum,
nudum; sepala ovato-oblonga, extus glabra vel interiora versus —
marginem tomentella, intus tomentosula, eglandulosa, post flora-
tionem reflexa; alabastra ovata, obtusa; petala late obovata,
_ emarginata, ad 2 cm. longa et 1.7 cm. lata; stamina numerosa,
antheris luteis ovalibus; styli liberi, circ. 5 mm. exserti, staminibus
_longioribus vix breviores, villosi. Fructus ignoti.
oS Szechuan australis: inter urbem Yen-yiian Hsien et viculum Hun-ka, ad
vias, alt. circ. 2600-2800 m., 11 Junii rora, C. Schneider (no. 1484; typus in
Herb. Arb. Arn. et Hb. Schneider).
This species seems to me most closely related to R. Sweginzowii Koehne :
= fom tame es Weddle, Rep. Spec. rx: 531. fig. 3) and R. eS
Wis. (see Bot. Mag. rgo: i. 3569), he oe eo disting
= fo having 7-9 leaflets and a different kind of wide-based Liseovd R atom pe
1917] SCHNEIDER—NEW CHINESE PLANTS "7
Rosa SOULIEANA Crép. var. yunnanensis, var. nov.—R.:
moschata var. yunnanensis Focke in- Not. Bot. Gard. Edinbgh.
5:69. 1911, nom. nud., non Crépin apud Franchet; Drets, l.c.
7:124. 1912 et 394. 1913, nom. nud.; R. Soulieana R. and W. in
Sarg., Pl. Wils. 2:314. 1915, quoad synon. Fockii et specim.
Forrestii, non Crépin.—A typo recedit rhachi foliorum et costa
foliolorum subtus puberula, pedicellis receptaculisque minute
flavo-glanduloso-pilosis et etiam interdum pilosulis.
Szechuan australis: inter viculos Wo-lo-ho et Hu-ma-ti ad viam versus
Yung-ning, alt. circ. 2800 m., 14 Junii 1914, C. Schneider (no. 1549; frutex ad
2.5 m. altus, patenter dense ramosus, floribus albis odoratis).
The main difference between the type and this variety seems to be the
fine pubescence of the rhachis and of the midrib of the under side of the leaflets,
MORIN’S plant, probably, came from the type plant i in the Jardin des antes
- Paris. The shape of the leaflets, which are described by FRANCHET as
“courtes, ovales et plus ou moins arrondies, 4 base arrondie, obtuses- arrondies
au sommet, plus rarement trés brusquement mucronées,” varies to a certain —
degree, and especially the leaves of ForrEst’s no. 2370 from Lichiang, which
is the type of var. yunnanensis of Focke, are rather acute at both ends.
VIBURNUM CYLINDRICUM Ham., var. crassifolium, n. var.—
aves crassifolium Rehder i in Sarg., Pl. Wils. 2:112. 1913. oe
A typo cum varietate ut videtur formis intermediis conjuncto |
differt praecipue inflorescentiis plus minusve vel satis dense aes
centibus.
Szechuan australis: in regione Yeu yeaa Hsien versus occidentem inter
viculos Hu-ma-ti et Wo-lo-ho, alt. circ. 2800-3000 m., 14 Junii 1914, C. Schnei-
der ae — —— ase #¢ °. Om Pibusens oe en
S hte Said ie ee free -3 metals); eodem loco, Octobri
= *9E4, C. Schneider ced brgees ee
78 BOTANICAL GAZETTE [yuLY
prope Kua pie, alt. circ. 3000 m., 21 Maji 1914, (no. 1345; frutex vel arbor,
3-6 metralis); in regione Hua-li, in dumetis declivium ad flum. Yalung, alt.
2300 m., 30 Maji 1914 (no. 1395).
VIBURNUM CALvUM Rehd., var. puberulum, n. var.—A typo
praecipue recedit: ramulis hornotinis et saepe annotinis biennesque
et etiam inflorescentiis plus minusve puberulis.——Fructus atro-
cyanei, nitiduli, ovato-globosi, circ. 5 mm. longi et 4 mm. crassi,
iis V. propinqui similes sed minus distincte apiculati; semina
ovoideo-globosa, ventre leviter sulcata, albumine ruminato.
Szechuan australis: inter Hoh-si et Yen-yiian Hsien prope pagum Lo-
ma-pu, in dumetis montium, alt. circ. 2200 m., 9 Maji 1914, C. Schneider (no.
1146; frutex virgultus, 1.5-2 m. altus, floribus albis, fructibus atrocyaneis) ; in
regione Kua-pie, in declivibus dumosis calcareis montium, alt. circ. 3000 m.
20 Maji 1914, C. Schneider (no. a typus in Herb. Arn. Arb. et Herb.
eider; frutex sempervirens, 1 m. altus, fructibus nitidis nigris).
According to the shape and he athe of the leaves, and to the size
of the inflorescence, this form is very similar to the typical V. calowm Rehd.
from southern Yunnan, of which the fruits are not yet known. The fruits
I collected are about the same as those of V. propinqguum Hemsl. which,
however, can easily be distinguished by its 3-nerved leaves.
There is another very interesting species I found in Yunnan
boreali-occidentalis: inter Hoching et Teng-chuan, in silvis apertis
_ prope Sung-queh versus angustias montium, alt. circ. 3200 m.,
29 Sept. 1914 (no. 2873; frutex 3-metralis). The shape of the
ovate-oblong or oblong-elliptic leaves, which measure up to 8 cm.
in length and 2.8 cm. in width, is similar to those of V. propinquum,
but they are not distinctl te and not 3-nerved at the base,
but have the same ‘nervation as V.caloum. The fruiting corymbs
are small, and bear only a few fruits, which, unfortunately, are not
yet fully ripe. They are almost globose, and about’5 im. in
_ diameter. I cannot refer this form to any sj th described _
£
- _ from China, but I believe it is very near or the same as V. atro- :
aoe cyanea oe C. B. Clarke apud Hook. and es FL. Brit. Ind.
BRIEFER ARTICLES
' ANELSONIA, A NEW GENUS OF THE CRUCIFERAE
As GREENE remarked long ago, the so-called natural families, as
Umbelliferae, Labiatae, and Cruciferae, contain relatively few natural
genera, and perhaps in no group of plants are generic limitations harder
to define than within some sections of the Cruciferae. Consequently,
there have often been included under one generic name plants that in
point of fact bear little real relationship to one another. The genus
Parrya, as it has been treated by many recent authors, furnishes, we
believe, an example of this pisinin pretation - generic Henitaticms,
This genus was drawn by Brown toi
of the far North, all characterized by showy purple- red flowers and
glabrous (or hirtellous with simple hairs) foliage. In 1891 GREENE
(Fl. Fran. 1:253) referred to Parrya, Hesperis Mensziesii Hook., a plant
previously made the type of a new genus by NuTTALL (T. and G.,
Fl. N. Amer. 1:89. 1838) under the name Phoenicaulis cheiranthoides
Nutt., and possessing much the same aspect as the species included by
Brown in his genus, but with the foliage whitened by a thick covering
of branching and stellate hairs. A onofthis
plant with the typical members of Parrya has disclosed the fact, however, cS
that technical but readily discernible differences other than the char- __
acter of the pubescence exist between Parrya and Phoenicaulis. _
more important of these are the lack in the latter of the conspicuous —
network of superimposed fibers that characterize the septum of sn
the absence of the loose epidermis so } omi t the seeds of the
latter genus, the tort :
species of Parrya, and the ea
of characters of this type bm thee | ‘proper delineation of — in the i
80 BOTANICAL GAZETTE [JULY
on vegetative characters or places too much dependence upon the often
fickle ‘“‘aspect.’’ Circumstances of this nature doubtless contributed
largely to the treatment by NE son (Proc. Biol. Soc. Wash. 18:187.
1905) of Phoenicaulis Menziesti as a species of Arabis, a disposition that
was adopted later by NELSON and Macsripe (Bort. Gaz. 55:374. 1913).
It must be admitted that the arguments in favor of this treatment are
far from weak; on the other hand, the highly technical nature of the
characters to be considered in the proper definition of groups in a natural
family must be borne in mind, and PrRantt has used to advantage, in
“keying”? Phoenicaulis and Arabis, the type of characters that furnish
the best contrasts between Parrya and Phoenicaulis. The very possi-
bility of considering P. Menziesit as an Arabis becomes, therefore, a
strong argument for its retention as a genus distinct from both Parrya
an
We now come to a consideration of the plant which prompted these
observations. This plant was described by Gray (Proc. Am. Acad.
6:520. 1866) from meager material that was far past condition as Draba
eurycarpa, and recently has been redescribed as Parrya Huddelliana A.
Nels. (Bor. Gaz. 54:139. 1912). Here again we have an instance of
the similarity of genera in this family, especially as regards vegetative
characters. This plant would not seem at all out of place in Draba
were aspect the only criterion we had to judge it by; and indeed the
original ; consists only of two small plants which are so mature
that the seeds have all fallen. But upon examination of complete
material it becomes obvious that Gray’s species is allied to Parrya and
_ Phoenicaulis. Itis not satisfactory, however, to refer it to either of these _
The branching pubescence, the inconspicuous white flowers,
the subentire stigma, the broadly ovate-lanceolate pods, and the nearly
membranous septum are some of the characters that forbid its reference
to Parrya. The loose cellular testa about the seeds, the not at all tortu-
ous areolae, and the i inconspicuous flowers are also characters in direct
re
contrast to Moreover, there is the unique habit
which suggests. Draba rather than either of the genera to which it is
most nearly related, but consideration of it as a Draba (to mention one
outstanding feature) is out of the question because of the singular seed
3 coat Although this is suggestive of the seed coat of Fore, it is of a
different quality and is not winged. |
Now in the proper generic allocation of these plants c “on:
be given only to the value of
1917] BRIEFER ARTICLES 81
and distinctive; and it seems to us that there is only one possible inter-
pretation of the problem which will conform to what experience has
shown to be the logical and practical treatment of cruciferous groups.
In pursuance of this view it becomes necessary to consider Draba
eurycarpa as representing a generic type intermediate in some respects
to Parrya and Phoenicaulis, and more closely related to these genera
than to any others, but at the same time more distinct from either of
these than they are from each other. In recognition of the notable
work of AVEN NELSON, we propose that this genus bear the name
Anelsonia.
The — characters of these related genera may be sum-
, marized as follows
Pods ovate-lanceolate, mid-vein obscure; sectame merely ‘membranous ranous;
seeds with a loose cellular epidermis, not margined, areolae not tortuous;
pubescence of branching hairs; petals white, little exceeding the pubescent
eras: Shes SS 2... ee ee _Anelsonia
Pods narrowly ensiform or more or less attenuate at both base and apex
mid-vein evident; seeds smooth without loose cpaletnis or, if this i is present,
more or less margined; uae usually red purple, di
Pets more or less attenuate at both base and apex; septum bearing a
conspicuous network of superimposed fibers; seeds with a loose cellular
epidermis usually more or less winged, areolae not tortuous; |
Pods narrowly ensiform; _ septum merely
¥.
yy tM tee,
and stellate; stigma subentire. Be Ae rrgec eis ae . Phoenicaulis 2
Anelsonia, gen. nov.—Siliqua compressa ovato-lanceolata costa
media i oe septo membranaceo-hyalino, evanido, Stigmati fere
a Anelsonia_ ann (Gray), oo a eurycarpa Gx, a
eae ‘Am. Acad. ee on CT halhaas Shares: A. eapeae ot. €
CURRENT LITERATURE
BOOK REVIEWS
Researches in plant physiology
ATxktns' has written an interesting little book, the aims of which can best
be expressed by quotations from the preface. ‘‘The general aim of the book is
to present to senior students and investigators the results of recent work in a
few of those branches of plant physiology which are at present attracting .
attention.” ‘‘By such a presentation of portions of the science which are still
in a state of rapid growth, it is hoped that further investigation will be stimu-
lated. The choice of material by the author was, to a considerable degree,
infucoced bad his Famiferity with certain Subjects of general interest, portions
tally by the staff of the School of Botany,
Trinity College, “Dublin. Upon these, rather than upon other researches
of equal or greater importance, he has felt qualified to write, on account of his
first-hand knowledge of many of the methods employed. A small amount of
hitherto b included. tal
A list of the chapter headings gives an idea of the content of the book:
Ss The carbohydrates of the angiosperm leaf i in relation to photosynthesis;
feth carbo-
‘ductivities in plants, and the factors which influence them; X. Osmotic pres-
sure in relation to plant distribution, m logy, and cell division; XI. The
functions of the wood; XH. The plant oxidases; ZXUIL. The oxidases in rea
“ror7] ‘CURRENT LITERATURE : 83
NOTES FOR STUDENTS
Taxonomic notes.—Burt? has described a new species of Pistillaria
(P. Thaxteri) which he records as the smallest known hymenomycete. It was
collected in Connecticut, and is so minute that the “‘fructifications are not
visible to the naked eye unless rendered so by special illumination and back-
ground.” The fructifications were observed scattered on the surface of very
rotten wood, “merely gregarious, not united into clusters,” and as many as
II5 were counted on an area 2X0.5 cm. The fungus is remarkable not only
as the smallest known “toadstool, ” but also for its extreme simplicity of
structure.
FERNALD has described a new species of Juncus (J. pervetus) from Cape
Cod, resembling J. Roemerianus in many particulars. It is stated that this
new species “is one of the many remarkable species of world-wide affinities
which are being discovered so frequently on the coastal area of southern New
England and southeastern British America.”
Gates‘ has had occasion to investigate Trillium in connection with his
work in genetics, and has been impressed with the great variability of the
genus in certain organs. In attempting to delimit the species, he recognizes
SE species with 9 varieties. T. venosum is described as a new species from
described in T. luteum, T. lanceolatum, T. grandi-
florum, and T. ovaium. ee Eee enn of reciaten © he eee se
brought together, and their number is remarkable. The author suggests that
the genus Paris has Seon Ginited fom the T. erectum group, and that Medeola
Sin ction be studies of Senecio, has presented § Losarty
comprising 16 species, 4 of which are described as new —
Hov
a ve ’ >
& eperations on August tr, (4 in water ona ret about 2 miles off
84 BOTANICAL GAZETTE funy
MacKeEnzig,’ in continuation of his studies of Carex, has presented the
“Californian representatives of the Ovates.” The list includes 25 species,
15 of which are described as new.
' Rosrnson® has published a detailed monograph of the American genus
Brickellia. The need of it, the author remarks, ‘‘ presents no unusual condition
among the larger genera of the Compositae.” The gi species, 11 of which are
new, are grouped in 9 sections. The systematic presentation is preceded by a
full discussion of the diagnostic value of the characters used.
RYDBERG,’ in continuation of his studies of the Rosaceae, has investigated
the species of Rosa occurring in — and Nevada. He recognizes 34
species, 12 of which are described as
Tipestrom™ has described a new tie (A. platyphyllum) from the
Wallowa National Forest of Oregon.—J. M. C.
Effect of carbon dioxide on respiration—Kipp" has studied the effect of
various concentrations of carbon dioxide on the rate of anaerobic and aerobic
respiration of seeds of peas with testas both intact and removed. The work
is marked by brilliancy of design, and in the main of aepigaroae In concen-
trations of CO, ranging from o to 50 per cent, the d anaerobic
respiration is proportional to the square root of the concentration. As the
concentration rises above 50 per cent, the depressing effect falls more and more
behind the square root of the concentration. Carbon dioxide also depresses
aerobic respiration when measured either by oxygen consumption or CO,
production. In the latter case the concentration effect is similar to that in
anaerobic ew soidgina is deficient, CO, has no depressing effect .
as ;
atio
occurring in n starving tissue) i is thus depressed The work throws considerable
" Inwotk ofthis sft ee bold be aretha the lt sterile and that
ca om Ce ction is that of the s EERE |
ssdicatac a scp aiid clcietion OF ema Ase aad aeto
apodemicit
1917] MacCAUGHEY—HAWAHAN FLORA 97
plant or group of allied plants has existed in the islands, the botanist would
be well advised to consider the fauna that is especially attached to these.
When one considers that trees little modified from foreign species, for example,
Acacia koa or Sophora chrysophylla, possess a great endemic fauna, not only
species, but even genera of birds and insects, quite restricted to or dependent
on them, and that some of these creatures are certainly themselves not less
remarkable in their peculiarities than the most peculiar of the composites or
lobelias, we may hesitate to attribute such plants to a later era than many
other elements of the flora, which at first sight appear far more ancient.
Again, while in the islands an abundant endemic fauna restricted to a
plant indicates an ancient occupation by the latter, the absence of such a
fauna does not necessarily imply the reverse. In a fauna of comparatively
few types it may happen that few or no species have reached the islands that
could become adapted to certain elements even after great length of time. [I
think that those who are in favor of the comparatively frequent accession of
immigrants to account for the great series of allied species, or groups of allied
eh ee ee HircH-
cock remarks in writing of the most recent portion of the group, the still
active Mauna Loa on Hawaii, when one considers how little the bulk of the
mountain is made up of the few flows delineated on the map, and how small
| by
that there ng i a f£ sl sy Le 8 ie e : i aaeeined
rap agelvors sae ieaemeanny "hae bra eed ala
up long before the Tertiary period. And here he is ee
eee e -
Iti is significant that the gy no ms are Coreikery absent oo
- the native Hawaiian dora: ao ‘and conifers I have been intro- —
duced in recent years.
98 BOTANICAL GAZETTE [AUGUST
1. Littoral—(a) Humid littoral, along the windward coasts;
(6) arid or semiarid, along leeward coasts and coasts far removed
from the mountainous interior.
2. Lowlands.—Up to tooo-1500 ft., with humid and arid sec-
tions, depending upon relation of topography to trade winds and
distance from interior mountains.
3. Forest zone.—(a) Lower forest (1000-2000 ft.), with humid
and arid sections; in early times this zone extended much farther
seaward on the various islands than it does now; (6) middle forest
Fic. 2—View from a dividing ridge between 2 long humid valleys, looking
toward the head of Kau-kona-hua Valley; fog-covered summit ridge, elevation 2500
ft., seen in distance; entire region covered with dense and unbroken rain forest; on
slopes and ridges trees average 15-30 ft. in height, in valley and ravines they rise
to 40-6o ft.; annual precipitation at head of this valley approximates 200-300 inches.
(1800-5000 ft.), range variable, with humid and arid sections; this
comprises in the humid areas the typical Hawaiian rain forest,
highly hygrophytic and very rich in endemic forms; (c) upper forest
(s000-go00 ft.), restricted to the high mountains of Maui and
Hawaii.
4. Summit regions.—(a) Xerophytic summits (gooo—14,000 ft.);
high mountains of Maui and Hawaii; (0) hygrophytic summits
: rine it}; peaks rising into the cloud zone, with summit bogs.
1917] MacCAUGHEY—HAWAIIAN FLORA 99
Palms
The palms furnish an interesting illustration of the 3 floral
elements: indigenous, native introductions, and modern intro-
ductions.** The capital city, Honolulu, is a veritable palm garden;
there are some 80 species represented, which have been gathered
from all parts of the tropics. There is scarcely a home or yard
without its palms; some of the finest driveways are colonnaded
with such stately species as Oreodoxa regia and Phoenix dactylifera;
Fic. 3.—Arid, deeply eroded summit ridge, elevation 2000 ft., of eastern Koolau
Mountains; absence of vegetation due partly to aridity, partly to devastations of
goats; remnants of original forest cover occur here and there in hanging valleys
near sky line and in deep ravines.
and certain of the old estates, the famous Hillebrand gardens for
example, are crowded with rare and choice specimens. The only
palm introduced by the natives (and this introduction is neces-
sarily more or less theoretical, in the absence of historical records)
was the coco palm. This species (Cocos nucifera) is widely spread
throughout Polynesia, and in early times formed a characteristic ?
feature of many Hawaiian shores and beaches. :
= es, ¥, The « economic woods << Hawaii, Forest a
hee! 1916. -
uarterly 14:696-
100 BOTANICAL GAZETTE [AUGUST
The indigenous palms are confined to the single genus
Pritchardia, and are allendemic. There are a number of Hawaiian
species, perhaps a dozen. The exact botanical status of these has
not as yet been fully determined. The species of Pritchardia
occur mainly in the rain forests and along exposed humid summit
ridges. They are scattered, are usually solitary or in small clumps,
never form pure stands, and constitute a very minor element in
the forest. From the standpoint of abundance or striking features,
Fic. 4.—Xerophytic promontory, Ka-ena Point, a typical “dry ridge” formation;
other similar ridges, separating arid valleys, seen to the right; in foreground a coral
beach formation covering ancient lava beds; note stratification of lava flows in the
faces of promontory, also extensive talus slopes.
the native palms are as disappointing as the native orchids. They
occasionally attain considerable height (40-50 ft.), but are cus-
tomarily of short or even dwarf stature. Pritchardia is confined
to the islands .of the Pacific. The Hawaiian species show close
affinities with those of the South Seas.
_ Many of the other monocotyledonous families are but meagerly
— The * Orchidaceae, for ee that attain unrivaled :
1917] MACCAUGHEY—HAWAIIAN FLORA IOI
luxuriance and marvelous specialization in many tropical regions,
have only 3 species in Hawaii, and these are all shy, poor, homely
little plants."© Pandanus is represented by one species, formerly
abundant in the lowlands. Freycinetia Arnotti Gaud. is a tall
woody liana, common in the lower forest zone of all the islands,
and often forming dense jungles.
The liliaceous plants of Hawaii are in part woody species;
none are bulbs, and none have particularly showy flowers. Of the
Fic. 5.—Lava flow of the smooth or “pa-hoe-hoe” type; shows invasion by
lichens and ferns; in arid situations lava flows retain a new, fresh appearance for a
long period of years; under humid conditions they rapidly disintegrate and are soon
covered with plant life.
5 genera, 3 are monotypic: Cordyline terminalis, a tall shrub;
Dracaena aurea, a tree; and Dianella odorata, a large herbaceous
perennial; all are abundant. Asielia and Smilax are confined to
the forest and upper zones, and none of the group occur on the
coastal plains or lowlands. There are no “‘fields of lilies’ in
Hawaii. Commelina nudiflora is exceedingly abundant in moist
* MacCavucney, V., The orchids of Hawaii. Plant World 19:350-355. 1916.
¥O2 BOTANICAL GAZETTE [AUGUST
situations throughout the lowlands, forming pure stands and
smothering other vegetation.
The large and highly diversified propiend order of the aroids
has no place in the Hawaiian flora, except 2 naturalized species,
Colocasia and Alocasia, introduced by the ancient Hawaiians.
Colocasia antiquorum, the kalo or taro, was the staple food of the
primitive Hawaiians. The plant was raised both in irrigated fields
(loi) and on the uplands (Kula). Alocasia macrorrhiza, the ape or
giant taro, was raised in clearings in the lower forest, and used
chiefly in time of famine. Ornamental aroids of many genera are
now abundant in Honolulu gardens, but these are strictly exotic, and
none of these are naturalized.
Another group that one naturally associates with a tropical
background is the Begoniaceae, and yet of the 400 species, only
one is native to the Hawaiian Archipelago. Our lone species is
endemic, and is so distinct from its relatives that it has been
placed in a monotypic genus, Hillebrandia. It is a beautiful plant
with ornamental foliage and fine showy clusters of pink flowers,
but is limited to such isolated and difficult regions ret few people,
either natives or whites, have seen it.
Lobelias
Gagne the crowning pinky of our flora are the arbo-
rescent lobelias. These constitute one of the unique elements of
the Hawaiian forest flora, and aggregate some too species, dis-
tributed among 6 genera, 5 of which are endemic. As RocK”
succinctly states, ‘nowhere in the world does this tribe reach such :
a wonderful Heres in such a comparatively small area.’
t families a
ThA Ge eh.
oS : comapeiang the Hawaiian land Siva ‘Many of the | species show
aliz zation. The extraordinary Mae of variation
S tionary impetus of ‘this ae oe Sake 3
the a —— lobelias ecenonss on | the continent, = of our: —
1917] MACCAUGHEY—HAWAIIAN FLORA 103
trees, and some reach the amazing height of 40 ft. Many species
have a slender, naked, palmlike trunk, closely marked with con-
spicuous leaf scars. This pole terminates in a large rosette of
foliage and a showy inflorescence. These and other characters
give the plant a deceptively primitive aspect.
The Hawaiian genera are Brighamia, endemic, 1 species;
Lobelia, 5 endemic species; Clermontia, endemic, 17 species;
Rollandia, endemic, 6 species; Delissea, endemic, 7 species; Cyanea,
endemic, about 45 species. There are many features, both struc-
tural and ecological, which strongly suggest that our lobelias are
the remnants of a very ancient flora, a flora that has well nigh
been obliterated by profound geological and climatic changes.
It is significant to observe that the other islands of the Pacific
are practically lacking in lobelias. Furthermore, in other parts
of the world these plants are notably alpine in distribution. Many
high mountains of the tropics and subtropics are marked by a
lobeliaceous flora similar to that of our Hawaiian mountains.
These and other facts in local phytogeography lean strongly toward
the geological hypothesis that at one time these island mountains
stood at a much higher level (perhaps thousands of feet higher)
above the sea than at present. Under this theory the islands as
they now stand are but the vesiee of a former exten land
ordinary
geographic distribution of the ‘Hawaiian arboreal mollusks. ne
undoubtedly has an application to such phytogeographic problems —
as are involved in weed attempt to elucidate ihe origin of pee
Hawaiian lobelias.. .
104 BOTANICAL GAZETTE [AUGUST
toa high degree by many of our species. As HILLEBRAND states,
“‘the polymorphism of the Hawaiian cyrtandras is extraordinary;
no single form extends over the whole group, and not many are
common to more than one island. The variations affect every
part of the plant, and branch out and intercross each other in
manifold ways to such an extent that it is next to impossible to
define exact limits of species.’”*® The evolutionary status of our
species is closely analogous to that of the native lobelias.
The species of Cyrtandra are largely confined to the humid
regions; they are precinctive and extremely shade-tolerant.
Many species are to be found only in the narrow-walled ravines
and dimly lighted recesses of the rain forest. C. cordifolia Gaud.,
C. Pickeringii Gray, C. gracilis Hbd., C. Kahilii Wawra, C. grandi-
flora Gaud., C. paludosa Gaud., C. latebrosa Hbd., and C. Lessoniana |
Gaud. are representative Hawaiian species of this genus.
Composites
Spiind only to the lobelias in importance are the Composine.
There are over 80 species, representing 29 genera; of these , 60 species
are distributed among 9 endemic genera. Several of the genera
(Argyroxiphium, Wilkesia, Hesperomannia, and Remya) show
“Many evidences of | isolated and specialized evolution and, as.
HILLEBRAND rema probably belong to the oldest denizens of —
our islands, a sepotition countenanced by the fact that each —
holds no more than two species.” With reference to the last
statement it must be remarked that several new forms in these
a probably of specific rank, have recently been discovered.
_ A number of these peculiar Compositae (Artemisia, Dubautia,
_ Raillardia) are arborescent, and alpine in habitat. On the ee :
_ mountains of Maui and Hawaii ii they reach an elevation of moe
1917] | MACCAUGHEY—HAWAIIAN FLORA 105
densely covered with shining silvery pubescence; from this body
arises a tall inflorescence (6-8 ft.) of showy purple flowers. This
unique herbaceous perennial is xerophytic, and occurs only at
high elevations on Maui and Hawaii.
Lipochaeta, Coreopsis, and Tetramolopium are large genera of
herbaceous or semiligneous perennials; there are 10 or 12 species
in each genus, mostly endemic. The flowers are small, but very
numerous, and form showy masses of rich yellow. Bidens, Agera-
tum, Xanthium, Sonchus, Vernonia, Erigeron, Gnaphalium, Fran-
seria, Eclipta, and Centaurea are common weeds of the roadsides
and fields.
Modern research in ornithology has demonstrated the existence
of several bird migration routes from South America to the north
via Hawaii. The Hawaiian goose and the Pacific golden plover
furnish specific instances of these long over-sea migrations. Inas-
much as a number of the endemic composites show close affinity
with certain Andean and other South American species, it is
highly probable that they were carried thither by migrating birds.”
A number of other native plants were probably brought by
the same agencies, for example, Rubus, several endemic species,
closely related to Pacific Coast forms; Nertera depressa, with
fleshy red drupes, a South Pacific Coast species; Fragaria chilensis,
which also occurs along Pacific America; Dodonea viscosa, with - : :
glutinous capsules, and widely a o sndtcemee, es
and others. :
: The vast family Leguminosae, rivaled in size and distsibasion
oS only ae the Compositae, i is abundantly represe ee
oe Sophora, tetany anit: a rina, are arbo
_ ‘ies occur in dae Canavalia, Vigna, ee
106 BOTANICAL GAZETTE [AUGUST
trees of Cassia, Poinciana, Peltophorum, Pithecolobium, and allied
genera.”*
A number of the indigenous legumes are beautiful, high-
climbing woodland vines, with showy clusters of bright colored
flowers; Syrongylodon lucidum, Vicia Mensziesii, Mucuna urens,
Dioclea violacea, and Canavalia galeata are examples of these.
Species of Crotalaria, Indigofera, Leucaena, Acacia, Mimosa,
Dolichos, Medicago, Phaseolus, and Desmodium are common road-
side weeds. The most valuable and widely known of our cabinet
woods, koa, is from the common forest tree Acacia koa.
Rubiaceae
The Rubiaceae comprise a large and diversified portion of our
flora. There are 13 genera, of which 4 (Kadua, Gouldia, Bobea,
and Straussia) are endemic. There are between 50 and 60 rubia-
ceous species; of these the majority are tall shrubs or arborescent.
The other genera (Gardenia, Plectronia, Coffea, Morinda, Psychotria,
Paederia, Nertera, Coprosma, and Richardsonia) occur in many
other tropical regions. —
Of special interest, because of their beautiful flowers, are the
__ two endemic species of Gardenia. The blossoms are large, white,
_ deliciously fragrant, and rank high among the wild flowers of
Hawaii. The coffee (C. arabica) was introduced in 1823, and its
cultivation spread rapidly to all of the larger islands of the group.
Although a combination of economic and cultural factors has
7 suppressed the coffee industry, the plant itself is thoroughly
, and occurs in many of the humid lower regions.
; Birds have eeeitedy snsted mi dis eminati ao
ae "hated trees and shrubs comprise a. ‘conspicuous and abun- ae
dant element in the native forests. Th oS
1917] MaACCAUGHEY—HAWAIIAN FLORA 107
species. Two of the three genera (Pelea and Platydesma) are
endemic; the third (Zanthoxylum) is world wide in its range.
Pelea, named in honor of the Hawaiian volcano goddess Pele, is a
large genus, with nearly 30 recognized species and an even larger
number of varieties. Like the species of Cyrtandra and the lobeli-
aceous genera, the species of Pelea are highly variable, with many
intergrading forms, so that as yet the species are poorly defined.
Platydesma is an isolated genus, with 4 woody species. Zan-
thoxylum has 7 species, 6 arborescent, and many varieties. The
majority of these are characteristic of arid leeward regions and old.
lava flows. There are no native citrus fruits, although the orange
has become naturalized in many districts, particularly in the Kona
district, on Hawaii. |
Violaceae
The endemic Violaceae are a distinct surprise to the mainland
botanist on his first excursions in our Hawaiian forests. Instead
of tender little herbs, he finds stout woody shrubs, ranging in
height from 3 to 6 ft. The flowers are quite like those of the
familiar eastern violets, and are white, pink, purple, or blue in —
color, according to species. There : are a or 8 species, ranging in
swamps, they cover r et ns der-
have ca aber :
= possibilities in the way of ceatvated v violet bushes. ne
and :
suggest novel horti-
108 BOTANICAL GAZETTE [AUGUST
It is probable that Hawaii originally received. its contribution
from the Malayan center, although its 4 genera are now almost
wholly endemic.
All of the 13 or more Hawaiian species are endemic, and of
these a number are sharply localized in their range. The 4 genera
are represented as follows: Tetraplasandra, 7 spp.; Reynoldsia,
1 sp.; Plerotropia, 3 spp.; Cheirodendron, 2 spp. The charac-
teristic American-Asiatic genera Aralia and Panax do not occur
in Hawaii.
Labiatae
The Labiatae are represented by 7 genera. Three (Sienogyne
with 16 to 18 species, Phyllostegia with about 20 species, and
Haplostachys with 3 species) are endemic. Plectranthus comes
from Australia, and Sphacele from the Pacific Coast of America.
The two remaining genera (Salvia and Siachys) are weeds of world-
wide geographic range.
Hawaii has no equivalent be the familiar mints of eastern
fields and waysides, such as catnip, peppermint, pennyroyal,
hoarhound, and a score of others. Our Sphacele hastata, endemic
from an Andean genus, is a typical example of precinctiveness. It
forms an extensive belt around the great volcanic mountain
Hale-a-ka-la at an elevation of about 3000 ft., and occurs nowhere :
else in the archipelago.
Many of the shrubby species sof - Phyllostegia and Stenogyne have
lovely masses of flowers, white, pink, and red, and give beautiful
color effects against the dark greens of the rain forest and the wet
— jungles which they inhabit.”
Malvaceae”
“The Malvaceae constitute a large family.
: Se oe exept hee arctic regions, md iad eed
_ _ the tropics pics. Hawaii is well endowed with this — :
ae group. "There ¢ are 2 endemic genera: Kokia, the Hawaiian free
cotton, with 2 species; — a apecien.. All of ae
1917] : MacCAUGHEY—HAWAIIAN FLORA ~ r09
The large genus Hibiscus has 6 or 7 native species, all shrubs
or trees, with large flowers of striking beauty. The blossoms are
white, pink, red, or yellow, according to species, and form a dis-
tinctive feature of the rain forest.
The cosmopolitan genera Malva, Malvastrum, Sida, and A butilon
are common on the semiarid lowlands. Gossypium, the true cot-
ton, includes the unique Hawaiian cotton, G. tomenlosum, a spread-
ing shrub, endemic, densely covered with white tomentum, and
growing in arid situations along the coasts.
Solanaceae
Of the 70 genera of this family, only 3 (Solanum, Nothocestrum,
and Lycium) comprise elements in our native flora. There are
many introduced Solanaceae (Physalis, Datura, Nicotiana, etc.),
some brought in at a very early period and now thoroughly
established. The genus Solanum has 6 endemic species, one
arborescent; in addition to these there are a number of weeds
belonging to this genus. Nothocestrum is an endemic genus of 4
arborescent species, and is closely related to the Brazilian genus
Athenaea. Lycium, a genus of 70 species, is represented in our
flora by a single widely distributed littoral anaes
ride although there are a number of endemic species. | ‘Some -
of the more important genera, from the st listribution
and number of species, are Bromus, Calamagrostis, Cenchrus, 8
phobia Prank Scag pera Dactylis, ees con as
stuc so
IIo BOTANICAL GAZETTE |AUGUST
The representation of Cyperaceae is roughly as follows: Cyperus
17 spp., Kyllingia 1, Fimbristylis 4, Eleocharis 1, Scirpus 2, Hypo-
lytrum 1, Rhynchospora 4, Cladium 1, Baumea 1, Vincentia 1,
Gahnia 5, Oreobolus 1, Scleria 1, Uncinia 1, Carex 5.
Absent pests
Hawaii is entirely free from any plants poisonous to the touch.
To the botanist familiar with the distressing prevalence of these
pernicious vines and shrubs in the continental woodlands, it is a
relief to work one’s way through a Hawaiian jungle with the
certainty of complete safety in this regard. Neither are there
any stinging nettles. Mucuna urens, the well known “cow-itch”
plant, whose pods are covered with stinging hairs, is naturalized
_ in certain restricted areas on the islands of Maui and Hawaii.
The Anacardiaceae are represented in Hawaii by a single
arborescent Asiatic Rhus (R. semialata Murray var. sandwicensis
Engler). This species extends from India and the Orient to
Hawaii, and is non-poisonous. Our variety is a small tree, growing
in isolated clumps in all the islands.
It is to be hoped that the pernicious T. vernix, T. Siaoes and
T. Toxicodendron of North America may never by any accident
reach Hawaii. The noisome Paederia foetida was accidentally
introduced a number of years ago, and its seeds, like those of
Rhus Toxicodendron, are abundantly distributed by birds. It
‘is now a pest in many ofthe valley, as it smothers all other
ni amene : : :
“Fems
Tees) genera and 185 species pte ophy
a 2 genera ae : " E
: oe 75 eek cent and over of endemic speci
-
1917] MACCAUGHEY—HAWAIIAN FLORA go 9
from the arid raw lava flows to the most humid portions of the
jungle forest. A number of species (Cibotium and Sadleria)
attain arborescent stature (8-35 ft.) and many others are of large
size.3_ The other extreme is found in the minute Hymenophyl-
laceae. These are abundant in the rain forest, and clothe the trees
with their filmy fronds.
There are about 22 genera of true ferns. The largest of these
are Asplenium, 40 spp.; Dryopteris, 21; Polypodium 14, Elapho-
glossum 8, Diellia and Athyrium 6, Sadleria 5, Trichomanes 4.
The number of species in the larger genera, and in some of the
smaller as well, must be stated as approximations, as many of
these species are in serious need of revision. Many of the forms
hitherto described as varieties will undoubtedly be raised to specific
rank upon careful investigation, and numerous specific wap tain
require redefinition.
Some of the abundant forms not indicated by the generic list
are Marattia Douglasii, Gleichenia spp., Gymnogramme javanica,
Vittaria elongata, Nephrolepis make Cystopteris Douglasii
Doodya media, Odontoloma repens, Micropelia spp., Schisostegia c
Lydgatei, Pellaea ternifolia, and Adiantum spp. These are sae of
genera represented by only a few species.
Salviniaceae are represented by a peceatly ssaroduved Asolla; a.
_ Marsileaceae by 2 endemic species of Marsilea; -Equisetales are
not represented. The Lyco Hodiale
es have 3 genera in the foes:
Lycopodium with to spp. and 5 endemic; Psilotum with 20 widely ae
distributed species; and ror agpe sigied 3 endemic and I other : <
species. About 5 5° of the F Wawan
RAT taal shame 25 ue ha
and t pee spe jes
Ii2 BOTANICAL GAZET TE [AUGUST
habitats of many mosses, which completely cover the water-
saturated ground of large areas, and mask the treacherous
quagmire.* The liverworts, including the Marchantiales, Antho-
cerotales, and Jungermanniales, are abundant in the humid
regions, many species being epiphytic and epiphyllous. Species
of Marchantia, Anthoceros, and related genera are conspicuous along
streamways and in other moist places.
Fungi
The larger fungi are conspicuously absent from the woodlands.
There are a few woody brackets, a few dull-colored mushrooms, a
few puffballs and trembling fungi. The sum total of all these
is insignificant, however, when compared with the rich fungus
flora of such.a region as the eastern United States. One may
gather more fleshy fungi in a day’s collecting in New York, for
example, than he would find in diligently scouring our forests for
a week. This condition is somewhat surprising, as the cool,
humid rain forest zone, with its abundance of decaying vegetation,
would appear to be favorable for the development of the fleshy
fungi. A number of species of slime molds occur in the ravines
and jungles. It is to be regretted that no comprehensive study of
the Hawaiian fungi has been made.*5
Lichens are abundant in all parts of the islands. They com-
_ prise the first invaders of the freshly cooled lava flows. They
-Juxuriate in the cool humidity of the rain forest and the summit
bogs. They cover the exposed cliffs and ledges of the middle
zones, and withstand the aridity of the leeward lowlands and of
the high mountains (6000-14,000 ft.). The lichen flora not only
_ occupies a wide variety of ecological areas, but furthermore is
Ls of considerable richness. No comprehensive statement can be
a and species, as the Haves venir: have never :
ay received exhaustive study. :
tropes a Beology 35 24-30. te
1917] MacCAUGHEY—HAWAIIAN FLORA 113
Aboriginal introductions
Any outline of the Hawaiian flora would be seriously defective
that did not give prominence to the numerous plant introductions
by the primitive Hawaiians in their migrations from Samoa and
the South Seas. Carefully gathered historical evidence has
established the fact that during a long period of time, probably
several centuries, the ancient Hawaiians maintained intercourse
with their kinfolk in the South Pacific, making the long voyages
in their splendid canoes. During this eventful period of migration
and intercourse with the south, about 25 species of useful plants
were consciously introduced by the natives, and perhaps a much
larger number unconsciously brought in as seeds and spores.
The list includes :°
*Colocasia esculenta; the taro; starchy corms used for food.
Ipomoea Batatas; sweet potato; many native varieties.
*Musa sapientum banana; many native varieties.
ocarpus incisa; breadfruit tree;
*Cocos nucifera; cocoanut palm; formerly ony common.
*Dioscorea sativa; yam; starchy tubers; climbing vine.
*Dioscorea i yam; starchy tubers; climbing vine.
*Alocasia n
II4 BOTANICAL GAZETTE [AUGUST
The starred names indicate species that have escaped from
cultivation. Many of these have become so thoroughly naturalized ©
and established in the lower forests, on the lowlands, and along
the beaches that they are easily confused with the true i ae ahs
flora.
The oe importation of this diversified series of edible,
fiber-p , oil-producing, and other useful plants, from lands
so remote, and by methods so primitive, betokens native, horti-
cultural skill of no mean importance. As stated by LypGarTE,
*“‘the successful introduction, perhaps acclimatization even, must
have meant repeated voyages, extending over generations or even
centuries. And not time alone, but patience and skill must have
been required for the successful introduction of a seedless tree
like the breadfruit. Under favorable conditions it is not easy to
propagate; exposed to the trying vicissitudes of a long canoe
voyage, weeks of wind gin weather and open sea, lack of water,
burning sun and blighting spray, huddled into the bottom of the
shallow canoe, how many, many failures there must have been.”
In conclusion, it may be pertinent to suggest that there is an
unwritten chapter in the history of Hawaii’s introduced flora, —
namely the introductions possibly made by the early Spanish
explorers. They undoubtedly visited the islands repeatedly, long —
_ before the discovery by Coox’?; there are numerous evidences of
their intercourse with the natives, and it is not all beyond the realm
of probability that some of the plants now thoroughly sparse
were brought & in by these early escent
i waiian Islands ds were — ed ‘Spaniard in November, a In ee ov a 2
200 years bef IE it
ee ae See
THE GAMETOPHYTES OF TAXUS CANADENSIS MARSH
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 234 —
A. W. DUPLER
(WITH PLATES XI-XIV)
Introduction
While the European Taxus baccata L. has been studied by a.
number of workers and its morphology is quite well known, up to
the present time no accounts have been published dealing in any
connected way with the morphology of the American form, Taxus
canadensis Marsh., records having been made of only a few scat-
tered observations. Although by some, including PitcER (7) in
ENGLER’s Das Pflanzenreich, T. canadensis is considered as merely
a subspecies of T. baccata, it has seemed worth while to investigate
its morphology and compare it with other forms, and especially with
the results obtained in the study of T. baccata, most of the work in
which was done a number of years ago. The present paper gives” es :
an account of the male and female gametophytes in connection ; oe
with Bsaed Mieneadl — i a —. wit
Wa
‘Whe miatedal want in the chad ins collected dur ng t
of a peso don, P
116 BOTANICAL GAZETTE [aucusT
Historical
Taxus baccata has long been a favorite form for study, the ovule
and the seed first attracting attention, and the early work, therefore,
relating almost exclusively to these features. The first study of any ~
importance relating to the gametophytes was that of HorMEIsTER
(x1), who reported some of the more obvious features of both the
male and female gametophytes. The history of the male gameto-
phyte has become further known through the work of BELAJEFF (3),
STRASBURGER (4), and JAGER (6). Miss Ropertson (18) made
some observations, but, in her own words, her “‘results on the whole
simply confirmed previous work.’’ CoxKER (g) studied the micro-
spores in T. baccata and several of its varieties. STRASBURGER’S
early work had to do more especially with the ovulate shoot and
the ovule, but in 1879 (2) he described the origin of the megaspore
mother cells from the hypodermal layer of the nucellus and gave a
few observations on the development of the female gametophyte.
The best accounts of the female gametophyte are by JAGER (6),
_ who gave a rather complete description from the megaspore to
the mature endosperm, and by StTrasBuRGER (12), who gave
attention particularly to the early stages, especially to the forma-
tion of the megaspores and the free nuclear situation. COKER (9)
_ also studied the megaspores. :
In T. canadensis itself very little work: has been reported. :
HoFMEISTER (r) has a note concerning the proembryo; CHAMBER-
LAIN (5) studied the condition of the microsporangium at the
ae of October; CoKER (9) reports “more than one embryo
8 . . . not uncommon in Taxus ¢ lensis”’; and THOMSON :
Ge) tas ted he conto of the megaspore menbrane ae
| _ Male gametophyte —
ae 3 CHAMBERLAIN (5) in material of T. ¢ nade is a
a en collected i in n the Chicago — October + eh found the i
ig math. :
: eS Leos as s the winter condition. : . Matec
a cells” divided, in 1904, during w
1917] DUPLER—TAXUS CANADENSIS Ei7
sporangium develops during the summer, and by the time men-
tioned the microspores are forming (figs. 2-12). In a single
strobilus all stages from spore mother cells to completed tetrads
_may be found. Different stages are also found in a single sporan-
gium, although here the range is not so great as in case of the
entire strobilus.
Reduction in the chromosome number and the formation of
microspores take place as the result of the usual two divisions of
the mother cell. The first division (figs. 2-5) results in two
hemispherical cells, and this is followed by the second division
(figs. 6, 7), usually in the same plane, resulting in the bilateral tetrad
of microspores, although the two planes of division may sometimes
be.at right angles to one another. Sometimes the second divisions
are not simultaneous (fig. 8). Further divisions may also occur,
resulting in the formation of more than 4 microspores from a single
mother cell, as many as 6 having been found (figs. 9-12). The
microspores soon separate from one another and become surrounded
by moderately heavy spore coats (fig. 13), the tapetum remaining
quite prominent and showing little signs of disintegration even at
this time. The microspore stage is the winter condition of the
microsporangium, the only noticeable change in the microspores.
between this and pollination being an increase in size (figs. 13, 14). :
, This growth takes place in the early spring, during the period in
which the strobilus i from the winter scales and piaene
its mature size (about the middle of April).
Torreya californica in England (10) and T. peti in :
- Florida (14) pass the winter in the mother cell condition. STRas-
BURGER (12) reports that in Taxus baccata the “pollen” mother :
: ay So far as fal gies T. ‘canadensis is is ; the only one of the :
118 BOTANICAL GAZETTE [AUGUST
17) are binucleate when shed, the microspore having divided
into the tube and generative cells while in the microsporangium.
The absence of prothallial cells is a feature common to the Taxineae,
Taxodineae, and Cupressineae.
POLLINATION.—In the spring of 1914, in the vicinity of Hunting-
don, Pennsylvania, pollination was first noted April 23. No
strobili were found shedding pollen on April 20, but 3 days later
pollen was being shed abundantly, especially in the more exposed
situations, and most of the ovules collected at that time contain —
pollen grains. JAGER (6), at Zurich, reports the beginning or
middle of March as the time for the pollination of T. baccata.
The pollen grains are wind scattered and are formed in great
abundance, while the frequent occurrence of both staminate
and ovulate strobili on the same shoot increases the chances for
pollination. In the material which I have examined there were
very few ovules which had not been pollinated, and sometimes
quite abundantly, as is evidenced by the frequency of several
pollen tubes in an ovule. The pollen is caught by the small
pollination droplet which protrudes from the micropyle of the
ovule and is drawn into the yeas ey the concentration of the
- droplet. | -
Inthe ovule the pollen grains are found 1 sf the .
— nucellus. While no definite pollen. chamber is ; formed, the outer- :
‘most cells of the nucellus begin to disintegrate about the time of
pollination, resulting in a ragged edge to the sonaicae on which the
_ pollen grains become lodged. a
POLLEN TUBE.—The pollen grain, oe on the nucellus, soon
. begins to elongate, the exine is ruptured, and the intine grows | out
to form the tube. The young tube soon penetr ellus, gO
: = once started, ‘invades: ‘the tissue very rapidly. ‘Within ae
te while others ~ not E have » penetrated s so a there being
1917] DUPLER—TAXUS CANADENSIS 119
nearer its margins, in some cases reaching close to the edge of the
nucellus (fig. 27). During the elongation of the tube there is also
considerable increase in diameter, such that by the time the tube
has reached the female gametophyte region its diameter is several
times greater than at first (fig. 22). A striking enlargement now
takes place. If the female gametophyte still consists of free nuclei,
as it frequently does at this time, it may be so crowded upon by the
enlarging tube as to be pushed to one side; or the megaspore
membrane may remain quite firm, retaining its shape, the tube then
being forced to-conform its shape to that of the resisting meg:
membrane (fig. 28). A number of cases of branching tubes ¥ were
found, the nuclear contents in such cases being near the point of
branching, while the branches generally have dense cytoplasmic
contents, indicating their haustorial activity. The enlarging tube
usually spreads itself over the micropylar end of the female game-
tophyte; it may go off to one side and penetrate far into the
nucellus; or it may grow along the side of the endosperm, passing
by the archegonia i in ‘the micnopyier end neil the endosperm. hes
turn f.
yw if
usually enlarges between them, while i * some ¢ cases the pollen tube
may entirely pass the developing fe: phyte and enl o
below it. It seems that in a oe female g te tap ei
developing from an upper megaspore (fig. 31). Ce
In case the nucellus is is inv d by a number take they a
produce a rather int tic ‘The female gametophyte -
is crowded upon fron reer’ sides cud i fi 1 quite
out of its normal shape. A case was s found of ar
120 BOTANICAL GAZETTE {AUGUST
their enlargement and crowding upon one another produces such a
complex that it is practically impossible to count the tubes except
by their nuclear contents. The tubes which are on the periphery of
the complex may be so crowded by the more interior ones as to
remain quite narrow and their contained body cells may even be
flattened by the pressure.
The cytoplasmic contents of the tube become quite vacuolated
early in the growth of the tube and in early stages contain a large
number of starch grains, although these apparently disappear in
the later stages. The cytoplasm is always more abundant near
the growing end of the tube, but when the tube enlarges at the
forward end the bulk of the cytoplasm remains more or less closely
connected with the nuclei of the male gametophyte. Frequently
in late stages the cytoplasm may contain accumulated masses,
irregular in shape and densely staining, and these may even be
discharged into the egg cytoplasm at the time of fertilization. :
DEVELOPMENT OF MALE GAMETOPHYTE.—Soon after pollination
the microspore begins to elongate, and the first division into tube
and generative cells takes place within 10-12 days after pollination
(fig. 16). This division results in two unequal cells (fig. 17), the
smaller generative cell being held in the base of the grain by a
_ plasma membrane, while the larger tube cell forms the elongating
tube. The division of nuclear material is no doubt equal, but the
tube cell nucleus soon becomes larger than the nucleus of the
generative cell, the former becoming ellipsoid and retaining this
shape tk the inder of its history. The cytoplasm of
the generative cell is denser eG — of ihe tube cell.
: ' As! ee aes, a 7. re ak
: » the grow-
a ing end, migrating rapidly be behind the tip of the tube ey iG, Os
oe EB yen before the ‘generative coll divides, the tube cell nucleus has”
usually gone some distance into the tube. The generative c sl ae
: . enlarges, pushes out its tim ting
_ found together in the basal par
t9t7] DUPLER—TAXUS CANADENSIS 121
The body cell soon migrates into the tube and is followed by
the stalk cell nucleus, the two usually being in contact and appar-
ently having passed into the tube together. During the growth
of the tube through the nucellus, up to the time when the pollen
tube reaches the female gametophyte, the 3 nuclei are in an axial
row, while later the stalk nucleus migrates around the body cell and
es a position besides the tube nucleus. Of these two nuclei in
the tube, the tube nucleus is generally to be recognized by its being
slightly larger than the stalk nucleus. The body cell begins enlarg-
ing at once after entering the tube. As it passes down the tube it
is slightly ellipsoid, but on reaching the end of the tube, as the
latter is enlarging about the endosperm, it becomes rounded as it
increases in size. The cytoplasm remains dense and the nucleus
becomes large. During the early history of the body cell its cyto-
plasm is uniformly Soneented through the cell, but : as it reaches
Teo wake pet vn laonn Kaenrrow Lass
Ps
and here eae delicate radial strands (fig. 23). "The nucleus,
which earlier occupied a central position, takes a more peripheral
one (usually on the side opposite to that on which the stalk and
tube nuclei lie), while the cytoplasm becomes considerably vacuo-
lated along the margin of the cell, he eRe Sinner peering
_ with the increased vacuolization. .
The division of the body cell into the two male cells takes place :
shortly before fertilization. Several mitot n
were found. — _ The nucleus of the body cell being at one side of the
_ cell, there is an unequal division of the cytoplasmic material. ae
_A broad spindle is formed and the cell plate laid down on it is 2
the ¢
lenticular i in outline, resulting i in the. formati
122 BOTANICAL GAZETTE [AUGUST
investment of the smaller nucleus. He speaks of “‘male nuclei’’
and not of male cells. His figure shows two nuclei in a common
cytoplasmic mass. STRASBURGER (4) and JAGER (6) both recog-
nized two “cells.” Miss RoBERTSON (18) figures the division of
the body cell, but no cell plate is shown on the spindle, even in the
late telophase; while her figure of the completed division lacks
clearness on this point, owing to a possible inaccuracy in drawing
or in technique. In her discussion she speaks of a “functional
male nucleus” and “‘inequality of the sperm nuclei.”
By the time the two male cells are formed, the vacuolization
along the margin of the larger cell has become quite pronounced |
(fig. 26), and this continues until finally the cytoplasm has prac-
tically all withdrawn from the plasma membrane and collected
about the nucleus. In this condition the male gametophyte has
reached its maturity and fertilization may now take place. Should
male cells fail to function in fertilizing an egg, as is frequently the
case where there are a number of tubes in an ovule, they remain
in this condition for a time and then disintegrate. Male cells
have been found in ovules in which th yo was iderably
advanced.
Two unequal male cells are ae for Torreya taxifolia (14)
and Cephalotaxus Fortunei (16), and the division of the body cell
into male nuclei in C. drupacea (17). Miss RoBertson concludes
that there are formed ‘‘a functional male nucleus” and a ‘“‘smaller
male nucleus” in T. californica (18). In an earlier account (11)
she had stated that the body cell divided into two nuclei of
_ equal size. There is evident among the Taxineae a tendency
toward the elimination of male cells in the formation of the so-
called “male nuclei” only. The inequality of these nuclei or cells
is another advance. A mere cutting off of the smaller nucleus ©
os from the body cell would be — = wie the final one, not -
- cell functioning asa male cell... ~* Tatas the : male gametophyte :
wt ie aes consists of the stalk and tube nuclei and the =
two male « This is ae ine comps
1917] - DUPLER—TAXUS CANADENSIS 123
division between the microspore and the cells functioning in
fertilization.
Female gametophyte
MEGASPORES.—STRASBURGER (2) long ago pointed out that in
Taxus baccata the megaspore mother cells are the end cells of a
series arising from the hypodermal layer of the nucellus, and that
they are clearly distinguished from the surrounding cells by their
larger size and larger nuclei. The same situation seems to hold for
T. canadensis. STRASBURGER (2) claimed several megaspore
mother cells; JAGER (6) agrees with him, but CoxKER (9) in his
study of T. baccata states that there is no evidence that more
than one megaspore is ever formed. He says ‘‘the mother cell is
hard to distinguish. At the time of its first division it is long and >
narrow, resembling very closely the cells adjoining.” As to the
number of mother cells, STRASBURGER was probably right. In
my preparations I have found no difficulty in recognizing the
megaspore mother ‘cells, nor does there seem to be any doubt that
there may be a number of them in an tee Only one, or occa-_
sionally two, may function, but other megaspore mother cells may
be present, by all the other tests of a saatlies tt The mother cells —
are distinguished from the other cells of the nucellus, not only by |
their size and the size of their nuclei, but by their different staining
reaction. The group of mother cells may be recognized in the
autumn or winter (fig. 33). The occurrence of two linear tetrads _
of megaspores (fig. 38) is sufficient evidence that there have been at _
least two megaspore mother cells in the case figured. —
STRASBURGER (12) and CoxEr (g) have given rather euiples :
descriptions of megaspore formation in Taxus baccata, and the :
Process is essentially the same in T. canadensis, so far as my prep-
arations show (figs. 338). In r. saccola the second division a
is said to he ci
124 BOTANICAL GAZETTE [AUGUST
STRASBURGER (12) states that the starch soon disappears from the
megaspore mother cells of T. baccata, but COKER (g) in his figures
shows starch grains in the megaspores as well as in the megaspore
mother cells. The starch is not confined to the megaspore region,
but is found abundantly in the adjoining cells, and some of it occurs
throughout a considerable portion of the nucellus in T. canadensis.
The method of formation of a tapetum about the megaspore
mother cells, as pointed out by STRASBURGER (12) in T. baccata,
also holds for T. canadensis. ‘These cells are formed more or less
obliquely to the long axis of the megaspore cells (fig. 34), are rich in
content, and stain differently from the megaspore mother cells.
THOMSON (15) speaks of the tapetum derived from the nucellus
as a “secondary tapetum,” in distinction from forms in which the
tapetum is derived from the sporogenous tissue, in which case it is
called a ‘‘primary tapetum.” GOEBEL pointed out long ago, how-
ever, that the significance of the “‘tapetum”’ is physiological, and not
morphological, and that it may have a variety of origins. The
megaspore mother cell seems to be the usual winter condition.
_ While SrrAsBURGER (12) says the megaspore mother cells of
T. baccata are completed in October and that further development
takes place the next spring, this does not always hold for T. cana-
densis, as I have found young female gametophytes of several free
nuclei in some of the material collected in November, 1913. Most
of the ovules taken at this time showed the mother cell condition,
but even in some of the ovules collected as late as December it
‘may be doubted whether the megaspore mother cells had become
fully matured. Evidently, therefore, the time for the maturity of
the megaspore mother cells and the formation of megaspores may © |
__-vary, yet the general statement may be made that the mother
oh ie the usual winter condition and that megaspore formation _
me - bani de takes ~ in the pone with the renewal of the growing =
1917] DUPLER—TAXUS CANADENSIS 125
the formation of young female gametophytes (figs. 39-44). The
further development of several megaspores will be described later.
Some interesting cases were found, such as those in which one of the
upper megaspores had evidently functioned, while the lower ones
had failed to develop, although still recognizable (figs. 30, 31).
In both cases figured the pollen tubes have pushed past the gameto-
phytes and penetrated to the central region of the nucellus.
THomson (15) in his investigation covering the megaspore
membrane situation in the gymnosperms reports that in Taxus
canadensis the megaspore membrane, while recognizable in the
early free nuclear stages of the gametophyte, is practically unrecog- _
nizable in later stages. This agrees with my observations that the
membrane is quite firm about the young female gametophyte, but
seemingly fails to develop with the endosperm and is soon lost sight
of. THOMSON associates this with the absence of the ‘primary
tapetum”’ and regards it as a specialized advanced character, indi-
cating that the Taxineae are “recent”’ as compared with some other
forms.
DEVELOPMENT OF FEMALE GAMETOPHYTE
Free nuclear stage—The first division of the functional sae :
Spores takes place soon after their formation, and other divisions,
which are always simultaneous, follow in rapid succession (figs. ‘
45,46). Th ; as the number of nuclei increases. . :
At first the nuclei are scattered i in the embryo sac, but as this
increases in si lated in the center, the cytoplasm —
with the nuclei dies alleg 6 paiphaeal position, ——
126 BOTANICAL GAZETTE [AUGUST
are developing, one grows upward, the other downward (fig. 51). In
the early stages the embryo sac is usually pear-shaped, the narrow
portion marking the original position of the megaspores, while the
expanded portion shows the region of growth (figs. 47, 51). The
growth of the embryo sac and the enlargement of the endosperm
after walls have been formed crowd upon the adjoining cells of the
nucellus in such.a way as to distort and flatten them, while no
doubt some of the nucellar tissue is also digested by the growing
gametophyte.
Wall formation and growth of endosperm.—The first formation
of walls between the nuclei results in a single layer of cells sur-
rounding the central cavity (fig. 50). The cells at this stage are
rich in starch, the starch grains having also been present during the
-free nuclear stages. Centripetal growth of these cells then begins
by the radial lengthening of their walls, the walls reaching the
center and forming a completely closed tissue before further cell
division takes place. Several cases were found showing this feature
in various stages, but in no case had periclinal walls formed before
the tissue was closed (fig. 51). Cells which in a single section appear
to be internal are merely the inner ends of cells abutting the margin
in other sections. At the very narrow upper end the cells are very
closely crowded together.
JAcER’s account (6) of the formation of the endosperm in
Taxus baccata differs in a few details from this, in that he states
“that the cavity is filled with tissue by the inward growth of a series
of cells formed by periclinal walls. His technique was such,
however, that he could easily have been mistaken in his interpre-
tation of the situation. The filling of the central cavity by growth
and periclinal divisions seems to be the rule among gymnosperms,
and is probably to be correlated with the size of the cavity at the
time wall formation begins. The smallness of the cavity in Taxus
— _may account for the method of tissue formation found here.
a Following the complete filling of the central cavity with cell :
oo. _tissue, periclinal walls come in, giving rise to several layers of cells
a between the margin and the center. Anticlinal divisions also take
- place soon and the vow of the endosperm it ins alk d rections co
aos cell divides into several neck cells, all in the tangential plane, ser serv-
1917] DUPLER—TAXUS CANADENSIS 127
Growth of the endosperm goes on rapidly, the greater meristematic
activity being in the central portion, especially in the basal region.
In the early history of the endosperm the cells are uninucleate, but
as the embryo develops they become multinucleate, while in the
central portion of the endosperm, below the growing tip of the
embryo, the cells become elongated, forming a conducting tract for
the food from the basal region of the ovule to the growing embryo.
This elongation ceases to show after the embryo reaches maturity.
In the mature endosperm, with the exception of the extreme
micropylar portion, an abundance of food material is stored, this
being the food supply of the seedling in the early stages of its
germination.
A comparison of the size of the endosperm at different times mn
its development may be of interest. In fig. 52 there are shown 3
outline drawings, to the same scale, showing the comparative size
of the endosperm at the time of wall formation (as in fig. 51), at
the time of fertilization, and at the maturity of the seed. It is
readily seen that the greatest growth of the endosperm takes place
after fertilization.
Archegonia.—The archegonium initial arises ba the outer-
most layer of cells and is recognizable very shortly after periclinal —
walls come in. The initials appear a short distance behind the
“point” of the endosperm, but always occur in the micropylar end
if the gametophyte is one which has developed from an inner — oS
megaspore; in case of a gametophyte from an outer megaspore the
archegonia will be on the side of the gametophyte toward the —
center of the ovule. The initials can be recognized by their slightly
larger size and by the size of their nuclei (fig. 53). The surrounding
cells form the archegonial jacket. The initial divides into the —
_ primary neck cell and the central cell (fig. 54). The primary yneck
ng merely Il, a “neck” hardly being
: = of the maturity. of the a are mere sane usually wi ith
able. These neck cells become flattened, and by the time
128 BOTANICAL GAZETTE : [aucust
ventral canal cell or nucleus, it may be regarded that this central
cell is the functional egg. This agrees with Torreya taxifolia (14).
In Cephalotaxus Fortunei (15) and C. drupacea (16) a ventral
nucleus is formed, in the latter disorganizing before fertilization.
‘This marks the final elimination of the row of canal cells, an elimina-
tion which has been such a persistent and gradual process from
bryophytes through pteridophytes and gymnosperms.
In the earlier stages of the archegonium the central cell nucleus
is near the upper end of the cell, but as the archegonium matures
it takes a more central position (fig. 55), the cytoplasm being some-
what vacuolated and supplied with an abundance of food material,
some of which stains quite darkly with the staining agents used.
The archegonial jacket is recognizable from the initial to the.
mature archegonium, but is not strikingly conspicuous as in some
other forms, and less so in the mature condition than earlier.
Usually there is a jacket about each archegonium, with several
layers of cells between the archegonia, but it is not a rare thing
to see two archegonia with only a single layer of jacket cells between
them, and several cases were found in which two archegonia were
surrounded by a common jacket, this latter condition being an
‘approach to the archegonium complex found in some of the other
_ groups of gymnosperms. Several archegonia are usually present
in a gametophyte, 4-8 being the average number.
_ SUPERNUMERARY GAMETOPHYTES.—Mention has been ke
of the fact that more than one megaspore may function. Hor-—
MEISTER (1) long ago pointed out the presence of more than one
embryo sac in Taxus baccata, and JAcER (6), STRASBURGER (22),
and Miss ROBERTSON (18) have found the same situation. STRAS-
_ BURGER ales oe usually one embryo sac develops; if more
than 1; on several ‘tales he a
Vii . ‘7 wee usually
ee ce Sine : Wt 4 : *
wel ¥
eral nuclei, the two embryo sacs usually lying beside one anoth
* ee Mg
S : : and. one case of one above the other. Coxer 2 (9) and Tuouson cs) a ; : :
1917] DUPLER—TAXUS CANADENSIS 129
two gametophytes, only the archegonia of the lower gametophyte,
however, being fertilized
In my material I find two gametophytes quite common, usually
in an axial row, although sometimes lying side by side (fig. 57).
One is usually larger than the other, the upper generally being the
smaller of the two, and both may produce archegonia, as pointed
out by Coker. Usually when 2 gametophytes develop in an
axial row the pollen tubes push in between them, and then the
archegonia are directed toward the tubes; but this is not always
the case, as sometimes there are 2 apparently equally vigorous
gametophytes, one above the other, and both with good archegonia
in their micropylar ends. The pollen tube has spread out above the
upper gametophyte, while the lower one is not in contact with the
tube at any point in the case shown in fig. 58.
Several instances of more than 2 gametophytes in an wre were
found. One case (fig. 59) shows 3 gametophytes with tissue, the
pollen tube lying between the two uppermost. No archegonia
were present in the upper one, but both of the lower ones have good
oe. pie of which has beer: fertilized and contains a pro-
embryo. Other cases show hytes, in in one of which (fig. 60)
2 of the gametophytes have formed tissue, while the other 2 are in
free nuclear condition, archegonia being present only in the lowest,
which also contains a proembryo, the pollen tube in this: Pag a
having pushed its way between the 4 gametophytes. — In
-
case (fig. 61) the ovule contains 3 g with tissue. ee
archegonia, while the fourth one consists of only a few paeaart 3
and, although lying between two ‘vigorous gametophytes with
tissue, retains its shape, evidently owing to the firmness of the
megaspore membrane. One ovule was ; found containing 5 ere ae
130 BOTANICAL GAZETTE [AUGUST
to which it may be suggested that there is an elongation of the
nucellus during the growth of the gametophytes, together with a
digestion of that portion of the nucellus immediately adjacent to
them. The megaspores were evidently in contact when formed,
but by the enlargement of the pollen tube between the young
gametophytes they become widely separated as the tube develops.
Fertilization
While the fertilized egg represents a new phase in the life
history and the account of it might be more properly included
with that of the embryogeny, it may not be out of place to give a
brief account of it in this connection. Ovules containing pro-
embryos were found in material collected May 21. Preparations
showing fertilization were found from this time on to as late as
the middle of June, showing that the time for fertilization is not
constant and may have considerable range.
At the time of fertilization the neck of the archegonium becomes
ruptured and the nuclear contents and part of the cytoplasmic
contents of the tube are discharged into the egg. The egg nucleus
has migrated to the basal portion of the egg; the male nucleus with
its investing cytoplasm comes in contact with the egg nucleus; the
_ cytoplasm of the male nucleus invests the two nuclei lying in con-
tact and forms a dense sheath about them (fig. 56). With the
_ fusion of the two nuclei the act of fertilization is complete. The
behavior of the chromatin in fertilization could not be determined
from i —— The cytoplasmic sheath about the two nuclei
also in Torreya californica (11), T. taxifolia (14), and Cephalo-
taxus : Fosteass (16) among the Taxaceae, as well as in several other
cases reported, namely, by CoKEr (8) in Taxodium; by Lanp (13)
i Ephedra; and poe NICHOLS (x9) in Juniperus communis var.
| -—
"The smaller male cell and the stalk and tube nuclei, together
2 peeomvesn hye ; oe hk we
a a
, when hen present, ,
-_*
ryoorevenafter
ae — —— _ may persist st for some time and _
- 2cog mz — t some Seige s of the p :
1917] DUPLER—TAXUS CANADENSIS 131
Time relations
The time periods involved in the reproductive process are
always of interest in the gymnosperms, as use is made of this
feature in determining the primitive or modern character of a group,
those having short periods being regarded as the more advanced
in this respect. In my material the time from microspore formation
to pollination was about 6.5 months; from pollination to fertiliza-
tion may be as short as one month, although fertilization generally
occurs after a longer interval, the time between pollination and
fertilization having a considerable range, with an accompanying ~
range in the time of the maturity of the seed. I have collected
mature seeds from the first week of July until late in September in
central Pennsylvania. BELAJEFF (3) shows a pollen tube of
Taxus baccata with two nuclei collected April 10 and a figure of
fertilization dated May 26. JAGER (6), at Zurich, reports pollina-
tion at the beginning or middle of March and fertilization at the
end of May or beginning of June. Miss Ropertson (18) reports
the time for fertilization at Kew to be about the middle of June.
STRASBURGER (4) speaks of fertilization taking place the first half of
July and the embryo complete by the end of August. None of
these accounts gives so short a time period as l have found for
T. canadensis.
Summary
Micissbor foceiation takes place i in the autumn. "There are no
indications of prothallial cells. The pollen grain is uninucleate :
when shed.
a on wnt) Pan, ‘
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KI Ee)
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57
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32
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ARBORES FRUTICESQUE CHINENSES NOVI. IV
CAMILLO SCHNEIDER
(WITH PLATE XV)
) Salix (sect. SCLEROPHYLLAE Schn.) tenella, n. sp. (fig. A,
ae. .—Frutex parvus squarrosus; .ramuli hornotini non visi,
annotini biennesque floriferi obscure purpurascentes, minute
puberuli vel fere tomentelli, dein glabrescentes, vetustiores cineras-
centes vel cinereo-brunnei. Folia nondum satis evoluta anguste
elliptico-lanceolata, apice obtusa, basi subrotundata, 11.5 cm.
longa, o.2-0.4 cm. lata, superne viridia, initio plus minusve pu-
berula, subtus discoloria, glaucescentia, sparse puberula vel ut
videtur cito glabrescentia, nervis valde tenuibus utrinsecus circ.
6 superne incisis, margine integerrima; petioli 1-2 mm. longi, pilis
subflavis tomentelli. Amenta tantum juvenilia feminea visa,
coetanea, anguste cylindrica, 3-4 mm. crassa, ad 2.5 n. longa,
pedunculis folia 3-6 Mest’ normalia Sproles puberulis Or |
5 mm. longis exclusis, rhachi t
rotundae vel ovato-ellipticae, ovariis sublc :
Auscae, :
gi jones ae 2 esa : ao
varia spare: isa soy brevissimo_ ad ain bifido eaten Pe
stigmata brevia, biloba; | 2, ventralis late ovata vel —
-ovato-rectangularis, dorsalis paullo 1 minor, similis similis vel 2 -partita. | aS
Szechuan australis: in districtu Yen-yiian Hsien, Prope pagum Liu-ku, ae
138 BOTANICAL GAZETTE [AUGUST
subdense albo-villosuli, deinde fuscescentes vel nigrescentes,
glabrescentes vel subglabri; gemmae juveniles dense villosae.
Folia satis magna, late elliptica vel elliptico-oblonga, apice
subito breviter acuta, basi rotundata, rarius leviter subcordata,
minora inferiora 6-8 cm. longa, 2-3 cm. lata, majora superiora
g-12 cm. longa et 3.3—4.8 cm. lata, superne saturate viridia, adulta
laxe (in costa densius) sericeo-villosula, subtus valde discoloria,
pulcherrime albescentia, pruinosa (non papillosa), plus minusve
(initio probabiliter dense) adpresse albo-sericeo-villosula, costa
nervisque lateralibus utrinsecus circ. 8-12 angulo 50~-80° a costa
divergentibus flavescentibus utroque latere prominentibus, reticulo
nervillorum gracillimo prominulo, margine integerrima; petioli
6-15 mm. longi, undique dense villosi, superne late sulcati; stipulae
ut videtur minimae, indistinctae. Amenta tantum fructifera
visa, tardiva, ramulos foliatos 1.5-4 cm. longos terminantia, cylin-
drica, ad 8 cm. longa et 1 cm. crassa, axi dense villosula. Flores
adulti inter fructus remanentes circ. 6 mm. longi; ovaria ovato-
oblonga, sessilia, dense albo-villosula; styli distincti circ. } ovarii
- aequantes, ad basim bifidi, stigmatibus satis marcidis angustis
_ oblongis bifidis brachiis styli fere aequilongis; glandula 1, ventralis,
sicca ovato-trangularis, brevis; bracteae late ellipticae, apice
rotundatae, pallidae vel brunnescentes utrinque villosae, ovario :
subtriplo breviores. Fructus maturi circ. 7mm. oe ovariis
_ adultis similes, ee
Tr. ng lye 1, Pe fod m3 J lt. circ. 3400 Mm.
: 30] er 4, € . Schneit (no 2059; tyP Ty A RO eet Schneider:
qliestile oa biotite}
= Unfortunately I collected only «few remnants of fruiting catkins, and I oo
oiserayhiips - female flowers nor th ee
a no doubt that this willow represents an excellent i
ee
1917] SCHNEIDER—NEW CHINESE PLANTS 139
The name is given in honor of Professor BAyLEY BA.rour, the distin-
guished Scotch botanist and director of the Royal Botanic Garden at Edin-
burgh, which contains an extremely rich collection of living woody and
herbaceous plants from China, especially from northwestern Yunnan.
119° Salix (sect. PstLostiGMATAE Schn.) Guebriantiana, n. sp.
(fig. C, 1-5).—Frutex erectus, satis elongato-ramosus, ad 6 m. altus;
ramuli novelli initio parce sericei, annotini biennesque glabri,
rubro-fusci vel sordide brunnei; gemmae flavo-rubrae, oblongae,
subglabrae. Folia juvenilia ovato-oblonga vel late lanceolata, apice
sensim subacuminata, basi cuneata vel rotundata, 3-5 cm. longa et
I-1.5 cm. lata, superne initio sericea vel sericeo-villosa, cito sub-
glabra, intense viridia, subtus plus minusve dense sericeo-villosa,
dein glabrescentia, discoloria, pruinosa, nervis lateralibus utrinsecus
circ. 12 angulo acuto a costa divergentibus, margine integerrima
vel saepissime versus apicem dense minute glanduloso-serrata,
matura ignota; petioli vix 5 mm. longi, laxe sericei; stipulae dis-
tinctae non visae. Amenta (mascula tantum visa) coetanea,
anguste cylindrica, nondum satis evoluta ad 6.5 cm. longa et vix
7 mm. crassa, pedunculo ad 1 cm. longo folia 3-4 normalibus
minora sed similia gerente excluso, axi laxe villosa; bracteae
_ concolores pallidae. ves pe ebais brunnescentes, obovato- —
tae, basi dorso. leviter saccatae, glabrae, filamentis ubduplo vel =
fere 3plo breviores, quam glandula dorsalis subduplo 0 longiores; ee
filamenta glabra, juvenilia satis crassa; antherae flavae, ovato- =
globosae; glandulae 2, separatae, ventralis. lata, subquadrato- oe
rotundata vel rectangularis et apice truncata, dorsalis illae vix vel ee
- paulo brevior sed angustior, oblonga, apice truncata. |
| ter urbem Yen-yiian Hsien et viculum Hun-ka, i
hneids Soe? _. Acca ee do
140 BOTANICAL GAZETTE [AUGUST
I take great pleasure in associating with this interesting willow the name
of Mgr. pE GuEBRIANT, bishop of the famous French Catholic Mission at
Ning-yiian-fu, in appreciation of valued service rendered to me while I was
staying in that town during the month of April 1914.
yer Salix (sect. PsittostiGMATAE Schn.) wolohoensis, n. sp.
(fig. D, 1-5).—-Frutex erectus, squarrosus, ad 2 m. altus; ramuli,
novelli tomentosuli, dein glabrescentes, olivaceo-brunnescentes,
biennes glabri, fuscescentes; gemmae foliiferae ovatae, obtusae,
adpressae, breviter pilosae, flavobrunneae, circ. 4mm. longae.
Folia firma, etiam majora vix satis evoluta, late lanceolata vel
anguste elliptico-lanceolata, apice sensim acuta vel minora sub-
obtusa, basi late cuneata vel rotundata, minimis exceptis inferiora
- 3-4m. longa et 1-1.5 cm. lata, superiora ad 7 cm. longa et 2 cm.
lata, superne sordide viridia, initio densius dein laxe adpresse
sericeo-villosa, costa flavescente plana, nervis lateralibus subincisis,
subtus valde discoloria, initio tomento sericeo subflavescente dense
tecta, dein argenteo-cinerea, adpresse sericeo-villosa (pilis costae
_ parallelibus), costa nervisque lateralibus circ. 8-10 angulo 45-60"
a costa 5s divereentibee: flavescentibus prominulis, rete nervillorum
_ haud vel indistincte prominulo, margine integerrima vel obscure
— _minutissime- distanter ‘glanduloso-denticulata; petioli 2-4 mm.
eu u sulcati, t sti /minimae 2-3.5 mm.
_ Jongae, semicordatae, glanduloso-denticulatae, ut folia pilosae. _
_ Amenta tantum fructifera visa, subsessilia, pleraque delapsa, ad
4 cm. longa et ad 8 mm. crassa, patentia, ad 4 nan 1 villosula, basi
foliolis paucis parvis vix ad rom 1 4 pig nee
satis similibus instructa; _ flores inter fructus 1 remanentes circ.
Ss mm. Jongi; oval :
ee a
De} ~ 21 Paes = . ae - 4
1917] SCHNEIDER—NEW CHINESE PLANTS I4I
Szechuan australis: inter oppida Yen-yiian Hsien et — in dume-
tis inter pagos Wo-lo-ho et Hu-ma-ti, alt. circ. 2000-2400 m., 16 Junii, C.
Schneider (no. 3490; typus in Herb. Arb. Arn. et Hb. Schneider; frutex
squarrosus ad 2-metralis).
This species much resembles S. psilostigma And., which I only know from
the good specimens collected by A. Henry and G. Forrest in Yunnan and
mentioned by me in the Pl. Wils. 3:116. From those the new species may be
distinguished by its leaves being a little more hairy on the upper surface and
not so thickly covered with a silvery silky pubescence on the lower one, by
its much more glabrous bracts which are not densely silky outwardly, and by
its shorter, entire, not deeply cleft styles. The fruiting catkins seem to be
shorter in S. wolohensis. Without having seen the male plant, it seems impos-
sible to determine the real relationship of this species, which comes from a
region that has never been explored before by botanical collectors.
Salix (probabiliter sect. DENTICULATAE Schn.) caloneura, n. sp.
(fig. G, 1-6).—Frutex elatior, divaricatus; ramuli hornotini
annotinique glabri, flavescentes vel olivacei, vetustiores rubro-
brunnei, interdum ad gemmas adpressas puberuli. Folia elliptica,
obovato-elliptica vel maxima late elliptico-oblonga, apice satis
subito breviter acuta, basi obtusa vel subrotundata, interdum —
subcuneata, Supers mntenge viridia, subtis valde discoloria,
# & Ee ; ee i aat gities 2 ste ri is %
‘ y ag See : cee >
nem -currentibus approximatis circ. a4 pro 1 cm. conspic ais, a
nervillorum satis distincto, valde juvenilia subtus dist : |
142 BOTANICAL GAZETTE [AUGUST
superantes. Fructus maturi circ. 6mm. longi, ovato-elliptici,
glabri, ut ovaria pedicellati, pedicello glandulam siccam fere duplo
superante.
Szechuan australis: in districtu Hua-li ad flum. Yalung, in dumetis, alt.
circ. 2800 m., 27 Maji 1914, C. Schneider (no. 1425; typus in Herb. Arn. Arb.
et Hb. Schneider).
Judging by the fruiting material only, I believe this species is best placed
in sect. DENTICULATAE Schn. near S. denticulata And., but it can be distin-
guished at once from this species by its much larger hives: The yellowish
nervation is very conspicuous on both surfaces of the leaves. I am not able to
determine the real relationship of the new species, not having seen any male
WS \ Salix (probabiliter sect. PHyLiciFoL1AE Dum.) squarrosa, n. sp.
Gee E, .1-5)—Frutex erectus, squarrosus, breviter ramosus,
ad 4 m. altus; ramuli hormotini non visi, annotini nigro-
-sesnagasren, glabri vel cai sie ad gemmas parce pipsseh,
peranne foliiferae itis chioagne acutae, subadpressae, cire.
I cm. longae, flavo-brunneae, glabrae. Folia nondum evoluta vel
minima, vix ad 1 cm. longa et 3 mm. lata, superne glabra, subtus
_ dense longe sericea sed ut videtur cito glabrescentia, integerrima,
- nervis lateralibus vix visibilibus, matura ignota. Amenta prae-
om sessilia, patentia, ovato-elliptica, vel breviter cylindrica,
-1.5-2.8 cm. longa, circ. 1 cm. crassa, dense albo-sericea, tantum
feminea visa ; bracteae ovatae, subacutae, ovaria florum superantes
sed vix apicem styli attingentes, nigro-fuscae, utrinque longe ser-
-jceae; ovaria ovata, dense breviter sericea, breviter pedicellata,
ete glandulam aequante vel sublongiore; styli fere glabri, —
-distincti, elongati, dimidio ovarii aequilongi, stigmatibus oblongis
apice haud vel paullo emarginatis stylo brevioribus coronati; —
- landula una, ventralis, Pag ae ees apes. truncata. oe
ie vix satis maturi pedicello sti c
ee
1917] SCHNEIDER—NEW CHINESE PLANTS 143
This is the first willow from central China, I have seen, which apparently
represents a species of sect. PHYLICIFOLIAE Dum. It is a much branched tall
shrub with short spreading branchlets. The short, silky female aments are
perfectly sessile. Without having seen mature leaves and male flowers,
however, it is impossible to be sure of the real relationship of the species.
\\55 Salix (sect. Drptopicryar Schn.) Faxoniana, n. sp. (fig. H,
I~5).—Frutex parvus, ramis prostratis radicantibus, ramulis
ascendentibus, o.2-0.3 m. altus; ramuli tantum novelli initio
sericei, annotini glabri, flavo-brunnei, biennes vetustioresque
obscure brunnescentes, deinde nigrescentes; gemmae elliptico-
oblongae, subacutae, circ. 5 mm. longae, glabrae. Folia obovato-
elliptica, elliptica vel elliptico-oblonga (vel minima ovato-elliptica),
apice rotundata, obtusa vel breviter subacuta, basi late cuneata vel
rotundata, 1.5:1 cm. ad 3.5:2-2.3 cm. vel angustiora ad 3:1.5
cm. magna, superne intense viridia, subnitidula, glabra, tantum in
costa subimpressa vel plana versus basim pilis sparsis praedita,
subtus valde discoloria, cinerascentia vel albescentia, pruinosa, in
costa nervisque lateralibus prominulis utrinsecus 6-10 angulo
7o-80° a costa divergentibus pilis sericeis sparsis instructa vel
glabra (juvenilia probabiliter dense sericea), reticulo nervillorum
satis distincto, margine satis indistincte et distanter glanduloso-
crenato-denticulata; petioli satis longi, superne in sulco lato plus
minusve puberuli, 8-13 mm. longi. Amenta tantum fructifera —
visa, ramulos ad 3 cm. longos normaliter foliatos terminantia,
cylindrica, densiflora, ad 5 cm. longa et circ. 1 cm. crassa, axi laxe
villosula; bracteae florum inter fructus remanentium oblongae,
fuscae, obtusiusculae, dimidio ovarii aequantes, versus basim parce
villosulae, apicem versus glabrae, plus minusve ciliatae; ovaria
elongata, conica, basi in pedicellum brevissimum quam glandula
-duplo: breviorem attenuata, oabek vel basi sparse villosula; styli
sicnett ee aa
144 BOTANICAL GAZETTE [auGuST
Schneider (no. 2319; typusin Herb. Arb. Arn. et Hb. Schneider; frutex 0. 2-0.3
m. altus); in declivibus rupestribus montium inter flum. Yang-tze et oppidum
Chung-tien, alt. circ. 3400 m., mense Augusto 1914, C. Schneider (no. 2375;
forma nullo modo ab no. 2319 diversa).
At first sight this species very closely resembles S. oreinoma Schn. from the
high mountains of western Szechuan, but S. Faxoniana differs from it and from
the other Asiatic species of sect. DrpLopictyAr Schn. in its glabrous ovaries,
the fruits being sometimes hairy only at the very base. The leaves are similar
to those of S. oreinoma, but the catkins of this species speente only about 2 cm.
in length (without the -sasaieds ,an and the bract zg , broader, and
truncate at the apex. i pliment to Mr c E, Faxon,
the assistant director 2 the Arnold Arboretum.
SALIX BRACHISTA Schneider in Sargent, Pl. Wils. 3:145. 1916.—
I described only a male specimen, and I add the following descrip-
tion of the female pent: dct: pygmaeus, trunco subterraneo,
bentik 1s; ramuli prostrati, initio olivacei
vel Parveackntes, dein flavo-brunnei vel flavo-rubri, tantum novelli
_ parce pilosuli, cito glabrescentes. Folia parva vel perparva, crasse
_papyracea, elliptica vel ovato-elliptica, utrinque acuta vel pleraque
apice acutiuscula et basi subrotundata, minimis exceptis 6:2 mm.
_ ad 12:6 mm. vel maxima ad 17:9 mm. magna, superne satis viridia,
costa incisa, nervis lateralibus planis vel vix levissime prominulis,
glabra, subtus pallidiora, non eaeecortie, costa nervisque
aoe lateralibus utrinque 5~7 angulo circ. 50-70" a costa divergentibus —
-distincte prominulis, an initio pilosa?, adulta glabra, margine
: Me subintegerrima vel plus minusve distanter minute ee
oo petioli oe superne sulcati, 2-4 vel foliorum 8mm
longi, ger mas plus minusve duplo superantes. Amenta trate
- pauca tantum v termi-
— zaflora; f fructus maturi, obovato-oblongi apice attenuati, :
1917] SCHNEIDER—NEW CHINESE PLANTS 145
3500 m., mense Augusto 1914, C. Schneider (no. 3454; ramuli fructiferi in Herb.
Schneider). .
It is with some hesitation that I refer this female willow to S. brachista
Schn., which is known only from male specimens collected by E. H. Witson in
western Szechuan. In most of my specimens there are no flowers or fruits,
the apex of the | hlets being infected probably by an insect and transformed
into hairy galls. The leaves agree well with those of typical S. brachista in the
nervation and color.
Together with no. 3454, I collected another female willow (no. 2318), the
leaves of which are even a little smaller, of a somewhat firmer texture, with
veins slightly impressed above and scarcely visible on the rather bluish grey
under surface. I am not sure whether or not this form belongs to the Hima-
layan S. Lindleyana Wall. or represents a form of S. Souliei Seemen. It is not
quite identical with those female plants from Tachien-lu which I described in
Pl. Wils. 3:62 as S. Souliei. I think it best, therefore, to give the following
description of no. 2318 from the snow mountains near Lichiang-fu:
Frutex pygmaeus facie S. Lindleyanae Wall. vel S. serpyllifoliae
Scop. ramis solo vel rupestribus adpressis, ramulis brevibus junior-
ibus olivaceis glabris (an novellis pilosiusculis?). Folia perparva,
crassiuscula, elliptica vel ovato-elliptica, utrinque obtusa vel
subacuta, rarius basi subr. minimis exceptis 5-7 mm. longa, —
2-3 mm. lata, superne satis laete viridia, glabra vel in costa incisa
sparse pilosa, nervis lateralibus plus minusve distincte incisis,
ebeed satis discoloria, glaucescentia (etiam novella ?), costa,
prominula, nervis lateralibus t utrinsecus 2-4 angulo 40-45" & Costa
divergentibus vix vel haud \ visibilibus, margin vel a
sa ti ; petioli distincti, 2-4mm.
longi, superne interdum ae gemmas duplo superantes. 2
Amenta ramulos perbreves liter foliatos t antia, fructi-
tera. Seteagierity circ. ‘Sf
attenuata, | ed ls sea redicellata, |
146 BOTANICAL GAZETTE [AUGUST
‘L°* Salix (? sect. SrEBOLDIANAE Seem.) dibapha, n. sp. (fig. I,
1-6).—Frutex erectus, ad 4 m. altus, ramuli hornotini laxe vel
densius villosuli (novelli satis dense flavescenti-tomentelli), anno-
tini satis glabrescentes, atro-fusci, vetustiores glabri; gemmae foli-
iferae ut videtur flavo-purpureae, subglabrae. Folia papyracea,
elliptica vel elliptico-oblonga, apice acuta vel longiora sensim brevi-
ter acuminata, basi cuneata, superne vivide laete viridia, tantum
valde juvenilia plus minusve flavescenti-sericeo-tomentella, costa
prominula nervisque partim exceptis cito glabra, subtus valde
discoloria, glauca, pruinosa, initio ut supra sericeo-tomentella, sed
citissime glabrescentia, tantum in costa elevata parce sericea,
nervis lateralibus utrinsecus 10-20 angulo 80-go0° a costa diver-
gentibus prominulis, reticulo nervillorum foliorum immaturorum
valde tenui vel vix visibili adultorum probabiliter magis conspicuo,
margine integerrima, minimis exceptis inferiora elliptica 4-6 cm.
longa et 1. 4-2 cm. lata, superiora oblongiora ad 8:2.4 cm. magna;
petioli 4-7 mm. longi, undique sericeo-villosuli; stipulae minimae,
semicordato-lanceolatae, villosulae, margine glanduliferae, vix ad
3 mm. longae. Amenta tantum fructifera visa, praecocia, elongato-
cylindracea, pedunculo ad 1 cm. longo foliola pauca parva ad 1-5
cm. longa ab normalibus vix diversa gerente Sayeed ad 8 cm. longa
_ et o.9 cm. crassa, axi villosa; flores i tes 2-3.5
mm. longi; ovaria ovata, sessilia, dense piliacaia: styli breves sed
_ distincti, {-} ovarii aequantes, apice breviter bifidi, stigmatibus
brevibus subbifidis oblongis; glandula 1, ventralis, oblonga, satis
_ brevis, bracteis florum adultiorum subduplo brevior; bracteae
ovariis juvenilioribus | aequilongae, elliptico-oblongae, obtusae,
_ brunnescentes, intus glabrae, extus infra medium villosulae et
_ciliatae, apice glabrae, ovariis adultioribus fere 3-plo breviores. :
oo Fructus ao ovato-oblongi, apice paullo attenuati, basi in |
22 sage glandula breviorem contracti, satis dense albido-
= : st} lis siccis eivasee circ. 3- s4 mm. ae set valvis
1917] SCHNEIDER—NEW CHINESE PLANTS , 147
distinguished by its more acuminate leaves with a longer silky pubescence on
the under surface, by its somewhat thinner fruiting catkins, its longer gland,
and by its longer more ees. cleft styles. The specific name is derived from
déBados, ‘double colored.”
In Pl. Wils. 3:122 I described a S. isochroma, referring it to sect. HETERO-
CHROMAE Schn., but according to further observations I believe that this species
represents only a variety of S. hylonoma; therefore, I suggest the following
combination: S. HYLONOMA var. isochroma Schn., n. var.
Alnus (subgenus CrEMASTOGYNE [Winkl.] Schn.) Ferdinandi-
Coburgii, n. sp—Arbor; ramuli novelli ut videtur dense fulvo-
villosulo-tomentelli, annotini plus minusve glabrescentes, atrofusci,
lenticellis sparsis flavo-brunnescentibus obtecti, vetustiores nigres-
centes; gemmae stipitatae, subglobosae, subglabrae, resinosae.
Folia matura chartacea, late elliptica vel subobovato-elliptica,
apice satis subito in acuminem brevem producta, basi rotundata
vel fere semper cordata, minora 5—7.5 cm. longa, 2.5—4 cm. lata,
a ad 14:8 cm. mint, oe pracsertim ad apicem satis
liter breviter gland serrata, superne
satis obscure viridia, costa incisa breviter glanduloso-pilosa excepta
glabra, nervibus planis, subtus discoloria, glaucescentia, pruinosa et
sub microscopio subpapillosa, glandulifera, ad costam nervosque
laterales valde prominentes flavobrunneos utrinsecus 12-17 plus
minusve fulvo- (et Bianduloso-) villosula {novella probabiliter |
satis dense t ; petioli crassi,
superne sulcati, glanduloso-villosuli, ‘61 mm. Tongi. Amenta
tantum feminea fructifera visa, pro subgenere Cremastogyne nor-
malia, ovato-elliptica vel ovato-subglobosa, ad 2 cm. longa et 1.5
cm. 2 Crane, plus minusve resinosa; pedunculi 10-15 mm. longi, laxe
i; > bracteae ut in tabula fig. bs a4 dehurstae, apice eee
ae ee Sods : , circ. 12mm.
_ Tongae et (apice) subaequi latae; semina obovato-rectangularia, —
- circ. 4 man, longa, als anes Cte. ee
ae tL
148 BOTANICAL GAZETTE [AUGUST
the broadly winged seeds of the two other known species of this group. The
female flowers of the new species are yet unknown.
As I pointed out (I. c.), the subgenus Cremastogyne is a very distinct one,
and differs widely from subg. A/nus Endl. and Almaster Endl. in its single male
and female aments, which appear in the spring on this year’s branchlets in the
axils of normal leaves. The male flowers are entirely apetalous (fig. K, 6-9),
and the female flowers, so far as I can see, agree well with those of
the other subgenera; they are shown in fig. K, 10-12. In fig. K, 12, the
small “‘prophylla” of the female flowers can be seen, which are hairy at the
apex. In A. cremastogyne the female flowers I have seen had always 3 stigmas.
The fruiting bracts and the seeds of A. Janata are represented in fig. K, 14-16;
those of A. cremastogyne are very similar.
I take the liberty of dedicating this excellent species to His Majesty King
oe I of the Bulgarians, an eminent botanist and patron of natural
‘Anxoxp Ansonertit
EXPLANATION OF PLATE XV
Fic. A—Saliz tenella: 1, young female flower with bract; 2, 3, stigmas;
4 Venee eee 5, dorsal gland; 6, bract with dorsal
a cha? B.—Salix Balfouriana: z, old female flower with bract; a ventral
- gland; 3, bract; 4, mature fruit. :
Lo ot -C.—Salix Guebriantiana: male flower; 2, anthers; 3,
~ ventral gland; 4, both glands with the base ofthe laments De bette thea :
dorsal g
Fig. D.—Saliz cites 1, old female flower with bract; 2, —
‘Fie. E.—Salix squares 1 female ower with Dract; 2 ’, stigmas; ah
¥ oda
PLATE XV
BOTANICAL GAZETTE, LXIV
SCHNEIDER on CHINESE PLANTS
REPRODUCTION IN THE CONIFEROUS FORESTS OF
NORTHERN NEW ENGLAND"
Ba MoOoRE
This ‘investigation was undertaken to determine the factors
governing the reproduction of the more important coniferous trees
in the forests of northern New England. A detailed study of a
single area was considered more effective than general observations
over a wide area, but the — is not by any means exhaustive for
the single area.
The work was done on Mount Desert Island, situated toward
the eastern end of the coast of Maine, in about the same latitude
as the northern part of the Adirondacks and northern New Hamp-
shire. The island is included in the spruce region according to
Hawtey and Hawes (3). This is strictly correct; nevertheless,
parts of the island show unmistakable ; signs of the more southerly
white pine region. The location of the island is” therefore. of
unusual interest. Being at the edge of the tension zone between
I50 BOTANICAL GAZETTE [AUGUST
are precipitous, due probably to water action during the post-
glacial submergence (5). The northern half of the island is com-
paratively level. The topography therefore offers a diversity of
habitats.
The climate of the island is a curious mixture of the marine and
the inland, the former, of course, predominating, but the latter
being found in places shut off from the ocean winds. On the north-
east side of the island the average annual precipitation is 48.3
inches, of which 16.1 inches or one-third comes in the growing
season (May-—September inclusive). This should be abundant,
but there are periods during the summer in which lack of moisture
is an important factor.
The mean annual temperature is 44° F., running from 21° in
January to 65.5° in July. The sea tends to keep the temperature
uniform, but it is uniformly cold, for it is beyond the Gulf Stream.
_ There are surprising fluctuations in temperature, however. The
large areas of exposed granite rock take up and radiate great
quantities of heat, so that the fluctuations, particularly in places
cut off from the ocean winds, must have a distinct bearing on the ~
vegetation.
: The vegetation, although predominantly northern, contains a
_ strong mixture of middle Atlantic elements. It contains not only
plants but forest associations belonging to both the boreal and the
_ transition zones (4). Furthermore, this island and Schoodic Point,
a small peninsula about ro miles to the eastward, are isolated
- stations for Pinus divaricata.
_ The forest associations of the island are 5 in number: (1)
_ spruce, (2) white pine, (3) cedar, (4) pitch pine, (5) grey birch- —
aspen. Over most of the island, except the parts recently burned,
ae the first 3a associations mingle in a rather confusing manner to form a : :
oe eae iotest containing eee di Proportions of red spruce, balsam fir,
ne, and white cedar, with an admixture of red maple, grey 2
1917] MOORE—CONIFEROUS FORESTS I5r
(Pinus Strobus). It occurs on almost any site, even bare rock,
provided there is moisture.
2. The white pine association, composed of nearly pure white
pine, isnot abundant. The association on Mount Desert, although |
predominantly white pine, contains a strong admixture of red
spruce and cedar, and sometimes of red pine (Pinus resinosa). It
occurs on somewhat drier sites than the spruce association.
3. The cedar association does not form as pure stands as the
two preceding ones. Although cedar predominates pa NeIE
there are generally considerable proportions of fir, spruce, an
white pine, with red maple (Acer rubrum) and paper birch te
papyrifera). It occupies the moist flats.
4. The pitch pine (Pinus rigida) association, generally sharply
separated from all others, is composed of pure pitch pine, or some-
times pitch pine and a little red pine. It occupies mostly the dry
rocky southern exposures. On rocky flats not exposed to full
_ isolation, white pine, fir, and spruce are creeping in under the pitch
pine; on these flats, if not elsewhere, the pitch pine appears to be
a pioneer association.
5. The grey birch-aspen (Betula populifolia Populus tremuloid
and y, following fires, andi is
ae sooner or later by the original coniferous forest. :
A striking feature of these forests, a ninsaaos common to many
spruce forests in the west as well as in th e
of fir reproduction under the spruce, even when the parent stand
is nearly pure spruce. It is unnecessary to go into the many
hypotheses advanced to explain this. Perhaps the most wide-
spread theory, and the one tried out in this investigation, is that _
the accumulation of acid in the soil under the spruce is detrimental . : :
_ to spruce and favorable ne fir. .
_@) shows that certain p or a racy th soi. ‘Could 2 s
152 BOTANICAL GAZETTE [AUGUST
same size and age, and were taken from the same place, so that
variations due to size and vigor are eliminated. Each soil was
placed in a flat approximately 8 cm. in depth, over which was placed
a lath screen made so as to give half shade. All flats were in the
open, were given no artificial watering after the first 2 days, and
consequently were all under the same conditions except for the
soil. These conditions were, furthermore, as close to natural forest
conditions as possible.
The 3 soils were (1) A thoroughly decomposed ‘forest humus
which had been taken from the forest and rotted in a field for 2
years. This has a moisture-holding capacity, when saturated, of
138. 5 per cent of its air-dry weight, or 82.6 per cent of its volume.
(2) Undecomposed raw humus, taken directly from the spruce
association, consisting of needles, cone scales, and other forest
litter. This is Cov1tLe’s “upland peat,” the forest “duff”? which
accumulates in northern regions because decomposition is retarded
by lack of sufficient warmth. Its moisture-holding capacity,
saturated, is 504.6 per cent of its air-dry weight, but only 65.1 per
cent of its'volume. The high percentage of water on the basis of
air-dry weight gives an idea of the extreme lightness of this raw
humus. (3) Mineral soil from beneath the raw humus. This is a
___ bouldery glacial till, a reddish brown sandy loam with but little
i properties
faa The reason is that it was
_ impossible to make wheat or corn produce sufficient root systems ce
oS in either the raw humus or the mineral soil. On the decomposed -
nus (soil [2] above) a single direct det wilting :
effi aha of 13 per cent. Calculations from the moisture-holding & <
ci ty at B eeteree,. which : are probably unreliable for these”
iIting nts of 21 sae
1917] MOORE—CONIFEROUS FORESTS 153
The decomposed humus was found to be neutral; the raw humus
showed an acidity of o.002 normal, and the mineral soil an acidity
of 0.00017 normal by CovILLE’s method. Yet by the TRuoG method
the raw humus was strongly acid, and the mineral soil of medium
acidity. Tests at the end of the growing season showed only a
small diminution in acidity.
The measurements showed that the growth of both fir and
spruce was most rapid on the mild humus, effectually disposing of |
the theory that acidity is required by fir, or favors the fir against f
the spruce. In fact, the difference in rate between the neutral
and acid cultures was greater in fir than in spruce, indicating that
spruce withstands acidity better than fir. Growth of both fir and
spruce on the mineral soil was slightly more rapid than on the raw
humus, except that toward the end of the season some of the spruces
on the raw humus began a second growth period which enabled
them to pass those on the mineral soil. White pine also did
better on the mild humus than on the mineral soil; on the raw
humus there were not enough trees of this species for erie
conclusions. |
The duration of the period of growth in length for the different :
species is interesting. Fir began elongating on June 1, and stopped ct
on July ro, 40 days later; spruce and pine began on June 5, and
did not stop until August Bese 10 aae eee ee
_ long as that of fir. Some of the spruce on the raw owed
a second growth period lasting until August 303 disk get
its shorter growing period, is a faster growing tree than spruce. : a
An examination of the root systems of the different species on —
the different soils, made at the end of October, revealed a oe
154 BOTANICAL GAZETTE [AUGUST
The roots of all species were thicker and thriftier looking on the
raw humus than on the mild humus, although fir and white pine
were a little more branched on the mild humus. Most striking of
all, the roots of all 3 species on the raw humus were still capable of
absorption, even at the end of October. This was shown by the
presence of a considerable number of the little translucent growing
tips which are found during the height of the growing season. On
the mild humus growing tips capable of absorption were almost
lacking except where the root came in contact with the wood of
the flat. In the raw humus the root tips which had ceased to
function became brown, while many of those on the mild humus
became covered with a white fungus. A black fungus, common in
the raw humus of the forest, was found attacking the roots on the
mineral soil more than those on the raw humus, indicating that its
presence may be due to low vigor on the part of the roots rather
than to abundance of spores. The rootlets in the raw humus
exhibited a propensity for searching out twigs and cones and
growing through them. -
- Raw humus appears to have an effect on damping off fungus,
_ quite the reverse of what might be expected. In an experiment to
determine the effect of drying out, such as the raw humus is sub-
| jected to under natural conditions in the open, upon the germina-
tion and establishment of Pinus resinosa, it was found that on raw
a humus kept artificially moist there was no damping off, while on
the raw humus which received no water except from rain the loss _
a from damping off was 44. ‘ ner cent of the seedlings germinating.
yrse on a dry than on a moist
: cn soil i is contrary to all previous gene The explanation is
_ probably y to hag found it in the great abundance of fungus spores in
y nursery soils, and in the LS
1917] MOORE—CONIFEROUS FORESTS 155
Experiments were also tried on the effect of these 3 soils on the
growth of clover, wheat, and corn. Clover, as might be expected
from its sensitiveness to acid, grew very poorly on the raw humus
and mineral soil, but throve on the mild humus. In fact, it
eventually died back and disappeared on the two former, lasting
longer on the mineral soil than on the raw humus. Kubanka
wheat did well on the mild humus, except for the shading, while on
the raw humus and mineral soil it grew poorly. The dry weights
per plant for Kubanka wheat sown June 24 and cropped Septem-
ber 15 were 0.53 gm. for the mild humus as against 0.08 gm. on
the raw humus, and only 0.03 gm. on the mineral soil. Corn
(Golden Bantam) did so well on the mild humus that it had to be
removed to prevent interference with the other experiments,
while on the raw humus it produced only 0.09 gm. dry weight per
plant, and on the mineral soil 0.13 gm. after growing for more
than 3 months. The corn, it will be noticed, did better on the
mineral soil than on the raw humus, indicating that this plant is
affected more by acidity than by’ poor aeration. On the other
hand, wheat grew better on the raw humus than on the mineral
soil; on the former it frequently died down but came up again,
while on the latter it showed less power of recovery. This would
indicate that wheat is less sensitive to acid than to poor aeration. =
Field observations on the root systems of spruce, fir,and white
_ pine showed that detailed studies of roots would probably yield
interesting results. Spruce roots form a dense mat in the raw
humus or “duff,” a mat so dense that hardly a square ce timete
under a spruce stand escapes. These rootlets keep i
ee ene pleas as athe humus Sonn those i in the |
a
| — cory ke ‘enormous, cade cannot t fail to be : an
. _Teproduction. “Fir roots a are | Cc all
156 BOTANICAL GAZETTE [AUGUST
affected by a fungus which produces black threads of mycelium on
the root tips. These threads prevent absorption and kill the por-
tion of the root attacked. Yet seedlings appear thrifty even when
a large proportion of their roots are affected in this way. Perhaps,
since the fungus attacks only the smaller rootlets, the plant is
able to develop new rootlets about as fast as the affected ones
die off.
A factor of more importance than hitherto recognized is dryness
due to the interception of precipitation by the crowns of spruce.
The lack of vegetation under a forest of spruce has generally been
attributed to lack of light. While light plays an important part,
there are probably many cases where lack of moisture rather than
lack of light is the determining factor. A rather striking illustra-
tion may be cited. Under the crown of a spruce growing in the
open was found a patch of forest floor similar in every respect to
the forest floor found under dense stands of spruce. Herbaceous
vegetation and tree reproduction stopped abruptly at the edge of
this spot, yet the crown of this tree was high enough to allow the
ground under it to receive ample light. The only végetation under
_ the crown was a few grasses and asters, light demanding but com-
_ paratively drought resistant plants. The bareness of this piece of
_ forest floor was due to lack of moisture, not to lack of light. This
was confirmed by moisture tests, which showed that the soil
: _ beyond thé crown, soil which had been giving up moisture to a _
thick herbaceous cover all summer and should consequently be
| rer than a spt which had given up nothing to vegetation and oe
1917] MOORE—CONIFEROUS FORESTS 157
often so dry that neither reproduction nor herbaceous vege-
tation can become established, no matter how much light it
receives.
Counts of the reproduction of spruce, fir, white pine, and cedar,
correlated with age, showed that spruce, fir, and white pine become
established only at intervals of several years, while cedar comes in
every year. The cause of the failure of spruce and fir to become
established every year is apparently not related directly to climatic
factors, because the season of 1916 was unusually moist and favor-
able, yet practically no seedlings of these 2 species could be found.
Probably the reason for this periodicity in spruce and fir reproduc-
tion is to be sought largely in the seed supply. White pine repro-
duced abundantly in 1916, so that climate can be eliminated as a_
factor; but since it is equally impossible to eliminate the matter
of seed production, the periodicity of white pine reproduction may
be due to both the season and the seed supply.
In fir there are indications of a periodicity of reproduction
which is of Poneuieranty more suse ehoorenio | en that due » the
seed supply. 1 about
middle age, the fir reereduction is ‘nearly all composed. of large : a
seedlings approximately 1-3 ft. in height; young seedlings are
Scarce. In these cases it appears that the fir came in profusely a : :
— a set of savisenies conditions different from the present oe
Just what these conditions were it is impos: :
out ie fester shy One of them may have been stronger light than
at present. Indications of this were found in. the fact that some _
_ Of these cases of fir reproduction occur in stands which were for-
_merly more open than they now are; also, small fir repr duction
is abundant in young stands with a full but not very heavy canopy.
= sion @. _ Another factor may b be d 2s lecré
ible to pos tea - =
153 BOTANICAL GAZETTE [aucust
Each species reproduces only within a certain range of factors.
This range is probably a specific characteristic of each tree, possibly
of each plant, and appears to be different even for trees growing
together in the same association.?, Determination of this range
for even a few of our more important trees would be a valuable
contribution.
New Yorx« Criry
LITERATURE CITED
1. BoerKER, R. H., Ecological investigations upon germination and early
growth of forest trees. Univ. Neb. Studies 16:1-89. 1916.
2. CovIL_e, F. V., Experiments in blueberry culture. U.S. Dept. Agric., Bur.
Plant Ind. Bull. 193. 1910.
3. Haw ey, R. C., and Hawes, A. F., Forestry i in | New England. New York:
ened — Pt
C. Hart, Laws of temperature control of the geographical dis-
- tribution of tweed animals and plants. - Geog. Mag. 6:229-238.
1894.
5. SHALER, N. S., The geology of the island of Mount Desert, Maine. Report
ee Secretary Interior 37987-1063. 1889.
« Sureve, F., The vegetation of a desert mountain range as conditioned by
climatic factors. Car. Inst. Wash. Publ. 217. rors.
7 Truos, E., EOeN eh te all sent i maios Sta:; Saiu: Wis. Bull.
249. 1975 :
oem, R,, Balsam fir. US. Dept. Agric. Bull. 55+ 1914.
_Stti (fond hat in pen eget in Ain he eis vg
POLLEN TUBE AND SPERMATOGENESIS IN IRIS
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 235
M. Louise SAWYER
(WITH EIGHTEEN FIGURES)
This study of spermatogenesis had its origin in an attempt to
find a satisfactory method of securing prepared as well as living
material for demonstrating pollen tubes to a class in embryology.
The fact that it was found possible to dissect out the pollen tubes of
Iris versicolor, so that tubes of various lengths, developed on the
stigma and style, became available for study, made it seem advis-
able to undertake an sph itiat of the pollen tube of this species.
Tubes were also secured in longitudinal sections of style and stigma,
and by sowing pollen grains on n culture media. ‘Tubes were grown
in sugar solutions, the 15-30 per cent proving more satisfactory
than weaker solutions. A culture medium was made by adding
30 per cent sugar solution to the sap which oozes from freshly cut
stalks, and abundantly from the clasping bases of the leaves. The
superiority of the latter over the pure sugar solution lies i in the fact _
that as the tubes grow longer they are less likely, in the cell = oe
‘sugar solution, to become distorted. Its disadvantage consists in
the difficulty of freeing the tubes from the gelatinous medium. — :
Flemming’s stronger solution proved the most satisfactory kill- :
ing fluid, and iron-hematoxylin has been the favorite stain.
successful dissection of the tubes is related to the structure of ‘the e :
Style. That organ arises from the ovary as a single structure, and Lae
oe at the height of about 1 cm. divides into 3 bra nches. !
_ Of a stylar branch (fig. 1) reveal the fact that cach branch is eee an,
__ ersed by a longitudinal groove. When the flower is re, the
_— Stylar- rove is vee ee wo |
BOTANICAL GAZETTE [aucusT
IQO0
a ee
and
”
.
» X124; |
oe Os ©
ee
grow,
‘om section of anther, |
view of tube nucleus and |
a
1-10.—Abbreviati iation: s are as foll ws:
fig. 1, transvers ae
pollen tubes
ie fron
i)
Se,
bg e:
: Bex a
CAS
2 s Wegurse Sass oer, ,
preeaaite
1917] SAWYER—IRIS 161
is continued beyond the stigma. By removing the covers of the
groove the canal containing the tubes lies exposed, and they can be
removed with needles.
Tubes grown in hanging drops of culture media show a rather
striking tendency to grow from the margins of the drop in groups,
the tubes being in close contact with each other. This fact is sug-
gestive when associated with the fact that from the stigma the
pollen tubes converge in two lines and traverse the stylar branch at
the margins of the groove, where the space is most restricted
(fig. 2). It has usually been assumed that the pollen tube is guided
in its direction of growth by chemotaxis. These observations
suggest that in Jris contact stimulus may be an effective guide.
Further investigation of this point is purposed. _
The structure of the newly formed pollen grain (fig. 3) was
studied in sections of the anther. The division of the microspore
nucleus was not observed, but it occurs in the anther, as would be
expected, and the generative cell is organized before dehiscence _
(fig. 4). The generative cell is slender, elongated, and somewhat 2
pointed when seen from the side (figs. 6, 13), and is fi over-
laid by the tube nucleus (figs. a: 5). In this condition the pollen —
is tin _ Hand pollination was successfully performed. ‘Usually
d, bu
speed fies oad a ees the si
t it was demonstrated ne eee ae
under which i it was located. “Observation on the rate of growth - SS
ny Be oes e, and thei sa ieths se
measured with an ocular micrometer. T 2 ndicates
BOTANICAL GAZETTE [AUGUST
102
t,
ws: pg, pollen grain;
Abbreviations are as follows: p¢
0 Pe ns
.
-
1917] SAWYER—IRIS 163
within the ovary. The pollen tubes occasionally branch. This
/ was observed both in tubes grown on the stigmas and in those
grown on nutrient solutions (fig. 8). In the cell sap sugar solution
some grains produced 2 tubes (fig. 9), indicating 2 germination spots.
Longitudinal sections of hand pollinated stigmas (fig. 11) show
pollen grains (fig. 5) which have essentially the characteristics of
the grains in the dehiscing anthers, and among them grains which
are producing pollen tubes. A tube (fig. 10) caught just as the
tube nucleus and the generative cell were passing the tube dis-
tinctly shows the latter preceding, contrary to the order that is
usually reported. In other cases, the tube nucleus led the way
from the grain into the pollen tube (fig. 7). The number of cases
thus far observed at just this stage is not sufficiently large to war-
rant a statement as to which of these conditions is prevalent in
Tris versicolor. Apparently it is usual for the tube nucleus to soon
gain the leading position. One instance (fig. 14) of the tube nucleus
in the act of passing the generative cell was observed. The peculiar
elongated and pointed anterior end of the tube nucleus is very
interesting and suggests a self-motile body.
The generative cell certainly usually passes into the tube before
its nucleus divides to form the male nuclei, but occasional grains
suggest the possibility that it sometimes divides in the grain. The
division of the generative cell has not been observed, but in tubes
_ dissected from the stigma, and in those grown in the culture media, ce
the generative cell has frequently been seen apparently containing —
2 nuclei (fig. 15m). The contents, which microchemical tests show
_ contain much starch, stain so heavily that it is difficult to differ- ee :
entiate the nuclei satisfactorily. The material seems to indicate a : : eS
_ Somewhat wide 1 a in | the position of the generative oe in i oS
164 BOTANICAL GAZETTE [AUGUST
in all of these cases no cytoplasm could be detected in association
with the male nuclei, and also that in all views of these male nuclei
one of them appears larger than the other, the larger one slightly
vermiform. It remains to determine whether this apparent dif-
ference is real or whether in each case one of the nuclei is seen from
the end. In the embryo sac section it seems probable that the
smaller appearing one is the one likely to fertilize the egg.
Summary
. The style of Iris versicolor is traversed by a longitudinal
groove through which the pollen tube grows.
2. It is possible to remove pollen tubes from style and stigma
and to grow pollen tubes in nutrient solutions.
_ 3. Measurements indicate that there i is an accelerated rate of
growth of pollen tubes.
4. Pollen tubes may branch or a grain may produce two tubes.
_ §. The generative cell is an elongated, somewhat pointed cell,
— tured precede the tube nucleus from the tube.
usuall y Occurs: aiter the penera-
2 ed
tv cl has entered the tube.
4. The male nuclei may leave the ecmative cytoplasm, and
a been eee a a
ae The male nuclei were serve ‘
ed in the embryo sac 79 hours :
2 after pollination. oes oy
writer is in debted to 5 Proke fessor oH. D. Dexswone of Beloit oe
| College for suggestion which led to aking of this inves-
_ tigation. “Acknowledgments | are = ~ Professor ae M.
2 Courter and Dr. CHARLES Tt.
‘the p tl
ae Seal
BRIEFER ARTICLES
ELLSWORTH JEROME HILL
(WITH PORTRAIT)
E. J. HILt was a well known figure to the Chicago group of botanists.
For over 40 years he studied the plants of the Chicago region. No one
was more familiar with them, or had brought so many of them to general
notice. He was much more than a collector and taxonomist; in addi-
tion, he was an ecologist before ecology was recognized as a subject.
He was born at LeRoy,
New York, December 1,
1833, and died in Chicago,
January 22,1917. His early
life was spent on a farm, in
which environment he began
to develop his love of natural
history. At the age of 19 he
was taken suddenly lame by
an affection of the knee, and
during the rest of his long
life, with intervals of relief,
this troubleaccompanied hi
After his first trouble, to eet
away from the northern
winter, he went to Mississippi
and taught for three years in
a woman’s college at Grenada,
afterward returning to New
York. In 1860 he began a
theological course in Union Theological Seminary, graduated in + 10h,
and engaged in pastoral work until 1869, when another attack of
lameness incapacitated him for two years. He then became a teacher
again, first in the high school of Kankakee, Illinois, for four years, and
then for fourteen years in the high school of Englewood, now a part of a
Chicago. In gee he gave up teaching and seiotens et eae oo
: entirely to botany.
166 BOTANICAL GAZETTE [AUGUST
Hill’s experience as a persistent field student is a lesson in patience
and courage. His numerous field trips on crutches and afterward with
canes; his devices to overcome the handicap of lameness while collecting;
his persistence in making these trips even when he paid a severe penalty
for exposure or over-exertion—all testify to the spirit of the man. Dur-
ing his later years he was a constant and welcome visitor at the weekly.
meetings of the Botanical Club of the University of Chicago, and was
always intensely interested in the various phases of modern botany.
His mind was open and progressive, turned toward the future of his sub-
ject rather one toward the past.
His | lished includes 162 titles, ranging in time from
1870 to 1916, and covering all the phases of botany that would attract
the attention of an active field man with broad interests. This journal
published 34 of his titles, the majority of them during the decade 1880-
1890, and the last one in toro. Certain genera received his critical
attention, among them being Potamogeton, Carex, Quercus, Prunus,
Salix, and Crataegus. Taxonomists will recognize the fact that these
are difficult genera, but it was their difficulty that attracted. _
The Hill Herbarium, which is said to include 16,000 sheets, the accu-
mulation of years of critical work, has been secured by the University of
‘Illinois. It represents probably the most valuable single collection of
Illinois plants, especially of the Chicago region, and it is fortunate that
| ae as te es ee M. C.
— RESISTANCE OF SEED COATS OF ABUTILON THEOPHRASTI
TO INTAKE OF WATER
oe In the fall of 1910 I gathered seeds of Abutilon Theophrasti (velvet
_ leaf) near Manhattan, Kansas, placed them in vials of roo seeds each,
— covered them with water, and stoppered the vials. ‘The results in the
e present time have been very similar. a
shad swollen within the ist 5 weeks and were
-xamine In December 1916 a “desk i in which o
1 and | x on
erates the past 6 years 22 of the remaining —
1917] BRIEFER ARTICLES 167
and germinated as quickly and apparently with as much energy as fresh
seeds. Of the original 100 seeds 24 still remain intact.
In order to ascertain the resisting power of the seed coats of velvet
leaf to water at various temperatures, in December 1916 I collected
seeds from plants still standing in the field. | Most of the seeds at that
time had dropped from the pods, and those I found were mostly hard-
coated. In one case only 3 seeds in 100 had swollen after soaking
48 hours at room temperature. Two lots of seeds of 100 each were
selected and each lot was placed in a small vial. The vials were then
filled with water at a given temperature and suspended in Dewar flasks
filled with water at the same temperature. At the end of 6 hours the
vials were removed, the seeds that had swollen were counted, removed,
and the naire seeds were returned for a similar period at a tem-
perature 5° higher, and so on until all the seeds had swollen. The tem-
perature of the flask for each period was kept practically constant.
The seeds in flask no. 1 were started at 30°C., and in no. 2 at 35°C.
The results are indicated in table I.
TABLE I
FLASK NO. I Fiasx No. 2*
Tempera- | Ti Number ~| Ti Number
Re er |) ee Pe eee ee
ac. 6 8 35 C... 6 e S
5 eee 6 9 Se 6 oo ae
4° Ce 6 Ig Ce * 6 12 :
6525-5 6 se es ee 6 as oe
oo 6 8 (Cage 6 13
See.0 lS, 6 cs eae 6 9
60... 6 12 G6. ..2 6 to
6§... 6 7 eee 6 oS
2 6 iS § ys. 6 4
75: tye es 6 5. oe
= _Tesistant may lie i in the soil many years 1s befo
—Wier E. D, Kan
CURRENT LITERATURE
BOOK REVIEWS
Contributions to plant physiology
In a little booklet’ of 95 _ is given the work of the department of plant
physiology at Johns Hopkins University. Livincston gives a description of
the department, discussing the aims kaa the work in progress or so far accom-
plished, to which is appended a list of the publications from the laboratory
arranged by years. The rest of the book is devoted to abstracts of work in
progress or recently completed. A list of the authors and titles of these
articles will give an idea of the number of investigators in the department,
along with the nature and scope of the problems being covered: B. E. Livinc-
E.E. FREE, The effects of deficient soil oxygen on the roots of higher ihau
_E. E. Free, The effect of aeration on the growth of buckwheat in water cul-_
tures; Symptoms of ‘Poisoning by certain n elements i oa Pelargomans pad chet
se, Th
1917] CURRENT LITERATURE 169
ganic salt relations of plants, and relation of plants to climatic conditions. A
quotation from the book expresses the point of view under which the work of
the moiassaas ie is wing conducted.
summarize e last age Paragraphs, our operations have been and are
ae toward ad The point of view here employed
may perhaps be envisaged if the reader will an the living plant in somewhat the
same general way as he might any complex machine, such as a gasoline motor, for
example. To understand its aera one must understand how and how much
to be engineering science as applied to the living plant. It can progress, then, only
through quantitative studies, through the comparison of efficiency graphs and curve-
tracings made by recording instruments, through the mathematical interpretation of
relations between conditions and process rates, etc., and it is with agg this sort of
studies that our investigations have to do.
It might be well if scientific d t g lly issued such statements
of their aims —_ progress.—WM. CROCKER.
NOTES FOR STUDENTS
Rhizoctonia.—In a paper constituting a continuati Sf hie satin
the genus Rhizoctonia, ErtKsson? adds. an account of two further forms,
R. Medicaginis DC. and R. Asparagi Fuckel. The paper deals largely with
historical and descriptive matter; the chief interest, ;
questions relating to the taxonomy and id morphology of ‘th
the Tut Do BP iadi-ncins
Hance f the pha of the geminata Lo ue
bs iting stage an calor fis < ic which he Had doxbs = 2
ca
170 BOTANICAL GAZETTE [AUGUST
root-felt fungus found on crocus, alfalfa, and many other hosts (of which 54
are listed by him) belong to a single species, to which the name Rhizoctonia
crocorum (Pers.) DC. must be applied as long as the fruiting stage remains
unknown. This view is based upon a critical examination of the data in the
literature and an extensive study of living material and herbarium specimens.
He regards the evidence thus far presented as insufficient for the identification
of the perfect stage of the fungus. Unlike Errxsson, he finds no resemblance
between the mycelium cached by spores of Leptosphaeria circinans which
he germinated and the hyphae of R. crocorum. Duccar further gives an
account of Rhizoctonia Solani Kiihn, which is the more common of the two
species in America where it is the widespread cause of “damping off” of
seedlings and cuttings and root-rot of various crops. This species is clearly
differentiated from the violet Rhizoctonia by characteristics of the mycelium
and the sclerotia, as well as by the effects produced on the host plants. Fur-
thermore, evidence seems to be sufficient that the perfect stage of this organ-
ism is Corticium vagum B. and C. In a later paper,‘ as a result of a study
of the data in the literature, this fungus is identified with the “‘ Vermehrungs-
pilz” common in the seed beds and cutting beds of Germany and France, and
also with the ‘ Mopopilz,” causing considerable damage to the seed beds of
cinchona in Java. The failure to recognize Rhizoctonia Solani as the general
cause of the “damping off” of seedlings in Germany and France, as well as
in Java, is attributable to wrong determinations of the European seed bed
fungus and the cinchona fungus of Java.
g diff, i by D between Rhi ton is Sean
2 ye * Soe Pt, ae an
i a ee es while R.
: _ crocorum had not, up to that time, been successfully grown. Recently,
however, DreHts reports successful cultures of the fungus from detached
_ masses of mycelium. he cg lgishome plone aurea
instance was a pure culture 0
®
on
of th ic Rhizoctonias of the
United States eek ee The chief features of the —
report are (x) a general historical account, (2) a discussion of the oe so
= 1 a the data relating to the hosts, occur ce
rence, and distribution of R. Solani and R.
ie ne tin i ome other countries, OTe a
1 e induce by these fungi in different plants, (3) eke calle a
aa “Deccan, 2 B. Me Rhisctonia ‘Solani in teladion to the “Mopopile” and mae ’
Verm eh Sp
a 916. os
e of | ee ES tee
1917] CURRENT LITERATURE 17t
cross-infection experiments with R. Solani, and (6) a description of the growth
of this fungus in various media.
The numerous cross-infection experiments carried out with Rhizoctonia
Solani are of special interest. Strains of the fungus from some 30 species
plants were used to infect carnations in several stages of growth, from the
cutting to the mature plant, both under glass and in the field. A number of
other plants also were infected with various strains of Rhizoctonia. The
results of all these cross-infection experiments can best be stated in the author’s
own words: “From these inoculation experiments with a large number of
different types of plants, we must conclude that all the strains studied, which
were obtained from a wide age of hosts ee dives gecprsplucst origin, can
attack the
No marked specialization was noted in any of the strains. Thus, all the
strains studied can be included under one form, Rhizoctonia Solani Kiihn. The
inoculation experiments show further that the virulence of R. Solani is very
variable, as is also the degree of resistance of the various host plants, both
depending upon a number of factors.” A study of the growth characteristics
confirmed this general conclusion. Strains isolated from the same host
species showed differences as great as those between strains isolated from
different species.
Matz? has described a form of Rhizoctonia occurring on the leaves and
stems of Ficus Carica at Gainesville, Florida. This form is regarded by him
as a distinct species, R. microsclerotia Matz. Aside from its foliicolous habit,
ae te oe ee ee
also capable of infecting fig leaves, without prod however
single ya fe Seat Bera eee rie while
-HASSELBRING.
eo
R. Soi pee ee
o™, + ee ee : 3 ~— 66 oe ee L eae
- ae : 1 i? 5 fee twtise Pee
th
ty
reported
rig Say lpn romng arrnt oy rgen bulge seen Ld in
cited. The most complete of these earlier lists is that of TiscHLEeR (Pro-_
gressus Rei Botanicae 64-284. 1915). IsHrKawa’ has compiled the most
5:1 aes
ever published, and in in each case has cited the authority. Besides,
172 BOTANICAL GAZETTE [AUGUST
estimate rather than an.exact count. All of the Myxomycetes show 8 as the x
number; in the diatoms only 3 genera are cited, the x numbers being 4, 8, and
64, the latter with 128 as the 2x number; in the Conjugatae 12 is the prevailing
number, and in most cases the 2x is not cited; in the Chlorophyceae the x
numbers are various, ranging from 6 to 32, but no 2x numbers are given; in
the Phaeophyceae the x numbers are 16, 18, 22, 24, and 32, with the expected
2x numbers; in Characeae the x numbers are 21 and 16, but no 2x numbers are
cited; in Rhodophyceae 8 forms are given, with x numbers ranging from 7 to 24
and with the corresponding 2x numbers. In the fungi the numbers are low
and the 2x numbers are given in comparatively few cases; the minimum +
number is 2, and it has been noted in 2 species; 4 appears in 24 species;
few have more than 8 as the x secsebiiigg and ae maximum number (16) is cited
in 6 cases. In the bryophytes 8 ber, having been noted
in 12 species, while 4 has been counted i in S species, and Lag in one case and 6 in
another. The all cases. - oa
the x number ranges from 6 to 24, with 6 ( conited tat species)
number. In the pteridophytes the numbers are comparatively high, the x
number ranging from 4 to 120, and 24 of the 35 species cited have 32 or more,
while only one (Salvinia) shows the minimum number. In the gymnosperms
12 and 24 have appeared so constantly as the x and 2x numbers that any
other countings need to be very thoroughly ‘supported; 34 species with 12 as
the x number are cited, and 3 which
known to have 12, ‘Deck there aie 15) 6 necies is which the seuer § he oot
been disputed. Otter tipabers are 6, 10, and 16. okies aman Ree:
28 are devoted to angiosperms. 3 in Crep
| to 45 in Chrysanthemum arcticum. Tick ce Gece take oa
” ledons than in monocotyledons, and the most frequent + numbers are 8, 12,
and 16. —
‘he lists valuable not only forthe systematically arranged citations of
one marae 2
the c erate which the chrome apps ter 8
- CH AMBERLAIN, :
: ;: sit Se SET | feature CHARLES :
¥ ig, uae :
1917] CURRENT LITERATURE 173
by shorter periods of darkness and light. Humidity of the air was figured to
a standard.
Potometer determination of stomatal aperture involves mass movement
of air through the stomates under differential pressure, while transpiration
involves static diffusion of water- vapor through the stomates. To clear up
the physics of the problem, DARWIN gives two quotations from Sir J. Larmor:
“The speed of diffusion through a narrow aperture between two open spaces .
is proportional to its diameter. The speed of a stream of air through such an
aperture, between open spaces having different pressures on them, is propor-
tional to its area if the effect of viscosity can be neglected, but proportional to
the 4 power of its area if viscosity is — Which of these conditions
prevails, or whether the circumstances intermediate, in a given case,
depends upon the diameter of the mem ca de “Diffusio n through a long pipe
or channel varies as the area, and flow through it depends upon a reduced
area owing to the flowing air adhering to the walls of the tube; in fact it varies
as the square of the area if viscosity is predominant. Thus if this be the case,
-provided the channels are of fairly uniform width, transpiration would be
_ portional to the square root of flow, the same law as that obtained for the case
of holes in a thin plate.” Darwin b th t nearly
represents the situation, for the first applies only to tubes whose lengths are
less than one-fifth of their diameter. As might be deduced from either of the
physica eigrag y zl. at L skh
l )
root of the rate of potometer flow, and another by plotting the rate of trans-
Piration for various stomatal apertures, and for 18 separate experiments finds _
RS tcl aah acai although there are many minor dis- .
temperature and 1 hum conten, which might go far to eliminate r minor
were not carried out in closely controlled — .
"abo a in explaining these discrepancies. ‘Much has been done since 1900 to ee
the air nnon
Put the material and
a -antien peigeopi sityecleigarighn step in that direction. mes a
174 BOTANICAL GAZETTE [AUGUST
planned so as to include 3 series of experiments. In the first series samples —
of freshly dug potatoes were collected and cut lengthwise aba two equal parts.
One set of the samples was used immediately for the d of moisture,
sugar, and starch. The corresponding halves were divided into 3 sets and each
set stored at a different temperature for 12 days before similar determinations
were made. The samples were stored at 30, 15.5, and 5°C. For a checka
number of whole potatoes were subjected to the same conditions. The second
series was a duplicate of the first, except that the potatoes were dug about 2
weeks later. This series would show any change occurring in the growing
potatoes after the first series was harvested. The third series of experiments
was modified so as to determine the effect of removal of the vines on the carbo-
hydrate transformations. The roots were not harvested until 10 days after
a killing frost.
HASSELBRING and HAWKINS pointed out that t to the rate of carbohydrate
transformations in stored sweet potatoes the Van’t Hoff temperature law was
applicable. In general, at 30° C. starch hydrolysis was rapid at first and soon
reached an end point. At 15°5 C. a more normal rate of transformation took
place, tending toward a state of completion. The hydrolysis at 5° C. was
markedly retarded. In spite of the utilization of reducing sugar in respiration,
HasSELBRING and Hawxrys were able to show a marked accumulation at
first and very Bite ——— accumulation. The concentration of the
F y luring the p Storage:
‘There w: was a a lagi in iais bi ease chee accel with the increase of
reducing sugar. The data suggested that the mode of carbohydrate trans-
: formation in stored sweet potatoes was from starch to reducing sugar, which
resulted in the formation of cane sugar as the end product. On studying the
effect of eee it was found that during their activity
the sugar content remained low. As as checked
by removal of the vines, the usual f . bo 4 a. fcwcts
‘potatoes manifested themselves. ;
es _HASSELB SSELBRING and Hawkins" have coused out that tbe internal changes
; storage must play an important réle in susceptibility to decay. Aside
poe the theseetical Uipnificance, it seems that this mode of attack on storage
" Problems of this nature will be of economic value—Frep W. GEISE.
a
_ Taxonomic selon SarsTO = in continuation of his studies of West a
| en @, Passifora @), Rondeletia (10), Eriocaulon G)» Dupatya, Pilea, —
Ichthyomet} , Castelaria, and Stenostomum | 2). a
1917] CURRENT LITERATURE 175
Fawcett and RENDLE™ have described new species of Tephrosia, Cassia,
and Erythroxylum from Jamaica
GaTeEs* has described a new species of Oenothera (O. novae-scotiae) from
Nova Scotia. It is related to O. muricata, but is distinct in leaf, stem, and
bud characters, especially as to pigments. The species was studied in con-
nection with the germination of 1000 of its seeds.
GREENMAN,® in continuation of his studies of Senecio, has preted
§ AurEI. The section includes 48 species, 5 of which are new, the descriptions
being accompanied by a full bibliography and liberal citations of exsiccatae,
espe such as occur in American herbaria. The same author" has also
described a new vinelike Senecio (S. Hollickii) from Jamaica, collected by
Britton and Hottick in 1908.
Miss Hitt has described a new species of Spirogyra colened: in the
basin of an old fountain in Seattle, Wash. It is named S. gigantica on account
of its size, the filaments being 173-188 » in diameter, the cells being 1-2
diameters long, and with 4-6 chloroplasts. It most nearly resembles S. crassa.
Husparp® has described a new species of A gropyron (A. acadiense) from
Cape Breton, Nova Scotia, rates to A. Smithis Ryd.
Naka,” plants of Japan and Corea, has
described 15 new species in several genera, and proposes the following new
MAL!
OLIVE in connection with a study of the parasitic ie
of Porto Rico, describe Botryorhi d Endophylloid 1ew genera, and also
4 species of Endophyll. as new nbinations, formerly referred t Aecidium.
PRAEC 2t | Spann yin bie A a Bae | BORA yes ey
GER,
described 8 new speciea-J M. C.
. awcerr, W., and Renpie, A. B., Notes on Jamaica plants. «Jour Baany :
ne 1917. ee
* GATES be, © nee eu ows, Trans, Nova Seoia Int, Sct
14: 141-145. ‘es 2. sai
. *S GREENMAN, J. M | Moma of the Barth ed Conde A me ica n species
- the genus Senecio. "Part I. Ann. Mo. Bot. Gard. 3: 85-194. bls. +5. be case
176 BOTANICAL GAZETTE [AUGUST
Enzyme activity of fungi—With a view of ascertaining the manner of
destruction of wood by Lenzites saepiaria, ZELLER” has made a general study of
e enzymes in the mycelium and sporophores of that fungus. Enzyme
preparations of the mycelium were made by extraction of dried and ground
cultures of the fungus grown on sawdust. The enzyme mixture precipitated
from the extract by means of alcohol was collected on filter paper and preserved
Preparations from the fruit bodies were made in a similar manner.
From the activities exhibited by the powder thus obtained, the author con-
cludes that the following groups of enzymes are present in the mycelium and
sporophores of Lenzites saepiaria: (1) of the esterases chiefly those affecting
the hydrolysis of the esters of the lower fatty acids; (2) of the carbohydrases,
maltase, invertase, raffinase, diastase, innulase, ligninase (by which the author
designates CzAPEK’S “‘hadromase”’), cellulase, hemicellulase, and pectinase;
(3) of other enzymes, emulsin, tannase, urease, hippuricase, nuclease, pro-
teinases, rennttase, oxidase, and catalase.
£. aot Tot anc
‘containing a gradually increasing percentage of resin, growth was only slighty
depressed in Pa i cent of resin. In emuls'
over 50 per cent of resin growth is sharply depressed, while in ‘ine
containing over 85 per cent growth is practically inhibited —H. HAssELBRING.
Texas root rot—Duccar* reports the finding of f a conidial stage of the
" fungous diseases of the cotton crop. The conidia. se nidia-bearing hyphae usually
occur in patches on the bare ground between the rows of plants and only rarely
in connection with the roots themselves. They are borne on swollen or club-— :
shaped branches recalling the conidiophores of some species of Botrytis. The
spore powder which covers the ground of the fertile — is ee bull.
es ie yphomycete genus Phys ichum as
P. omnicorum (Shear) Duggar. ea
oe equation of Long IandHsxr has pase tt ofthe plants : :
~ City. a will serve for comparison witl At cei’ is and as a abe : ce
VOLUME LXIV NUMBER 3
ee
BOTANICAL GAZETTE
SEPTEMBER 1917
ROOT SYSTEMS OF CERTAIN DESERT PLANTS
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 236
M. S. MARKLE
(WITH THIRTY-THREE FIGURES)
Introduction
Although the aerial parts of plants have leng been studied,
little was known of the nature of the subterranean parts until the
work of CanNon' upon the plants of the region about Tucson,
Arizona. The sup position had been that in general the roots of
desert plants are of g enetratic The work ee
of CANNON showed ‘that while this this is is so tim true, st
: : a : : oe ee
area att, ‘ 1 length oe al ike
weh SPL SAS
Since the soil conditions and the flora of the vicinity ‘of Albu- —
querque are different from those at Tucson, a study of the rootsof =
‘Plants was undertaken in that vicinity, during the first half of f the e
“year FOr, Divers incre lies i in | the steses of the sees ey ule, on
- : very d dry.
178 BOTANICAL GAZETTE [SEPTEMBER
concluded from this that previous to the deposition of these beds
there was here a deep trough, which other evidence shows to have
been the bed of a large river, which existed at a period of greater
precipitation and was subsequently filled with stream-borne
material. On account of its fluviatile origin the material is
extremely variable, being composed of layers of sand, adobe, clay,
gravel, boulders, and combinations of these materials, with marked
local variations, both horizontally and vertically. On this mesa
and the numerous arroyos which dissect its edge grew the plants
studied.
One of the principal features of the soil in the habitats described
by CANNON is a thick layer of hardpan, or caliche, beginning at a
depth of about 30 cm. and extending indefinitely. This is so hard
as to prevent root penetration, except through cracks. Such
layers are common in arid regions, and are formed, according to
the opinion of CANNON and others, through the concentration of
salts left by the evaporation of ground water gradually ascending
by capillarity. Rainfall dissolves these materials, carrying them
downward. These two processes result in the formation of a
gradually increasing zone of precipitation. In the Albuquerque
region this zone is very poorly developed, often being noticeable
in a fresh exposure only by the presence of a whitish streak or
pebbles stained with lime. When dry, such soil becomes very
hard, and it is evident from the appearance of roots entering it
that it offers considerable resistance to root penetration, but
does not prevent it. When wet the hardpan is soft and easily
_ penetrable. — natural conditions, however, it is generally
is | | arid than that at Tucson, ~
= 4 an average fic 10 years | giving a precipitation of 7.44 in., as com-
3 pared with an average of 11.17 for. Tucson. Much of this small
“rains in the summer oe tes ones ———: from. the :
“summer rains. a i a
1917] MARKLE—ROOT SYSTEMS 179
months prevent the growth of the winter annuals so characteristic
of the Tucson region.
TABLE I
RAINFALL
Jan. | Feb. | Mar.| April) May | June | July | Aug. Sent, Oct. | Nov. | Dec. | Total
Tucson. ... 79|0.90/0.77/0.27\0.14/0. 26|2.46|2.66|1.16/0.64/0.81|1.00|/11.17
Albuquerque,
average... . 0.4810. 33/0. 22/0. 26/0.69/0.35|1.43|/1-07|1.70|0.77/0.46) 31 | 7-44
Albuquerque,
TORRE 0.68]0. 56/0. 51/2.05/0.00|0:00) eS Ares ae ee
TEMPERATURE
| x803 | s808 | 180s | 1896 | 807 | 2808 | 3800 | 1000 root | 902
minimum II Ol 3) M41. 3 ° ee 4{| 42
Absolute maximum 98 | 95 | 95] 100 | 95 | 104 | 104 | I0r | 99 | 100
EVAPORATION FROM A FREE WATER SURFACE
a caienl a pie ae
fapestl 73] 1.49 -
The data for Tucson are rc i pila ree wid “MacDoven
= 2
soon found that such data are of little value, since on account of
the fact that the soil is composed of stream-borne material, it is.
subject to extreme local variations, even within the habitat of a
‘single plant, as is shown in th iptions of the habitats of most _
-h nitions |
_ of the plants given in this paper. "Samples of soil from different — ee
| levels in the habitat of forces canescens showed the ane : rs oe
180 BOTANICAL GAZETTE [SEPTEMBER
several times the normal amount, the figures would have had even
less value than usual. Similar variations in water holding capacity
and wilting coefficient would result from the lack of uniformity in
the soil.
On account of climatic differences, the flora is very different
from that of the Tucson region. The larger cacti are absent here,
all being low forms, excepting Opuntia arborescens. No tree is
found on the mesa or its arroyos, and the bushes, except Chilopsis
saligna, are seldom more than 5 ft. in height. The period of
greatest growth follows the rainy season, whenever it may occur.
There are no winter annuals here, the corresponding forms being
either biennials or summer annuals. The annual plants are greatly
in the minority, the most conspicuous part of the flora being
composed of perennial herbs.
The principal plant associations occurring within the area
ane are as follows.
. The Penton: association, _chaeactenized by the grama and
| sees , but now much
: invaded by ruderals, such as xs Cakes Scvothrae and Salsola.
2. The Dysodia-Ephedra association, dominated by Ephedra
ietjores and Dysodia acerosum. The majority of the plants have
reduced aerial parts and a large root system. The association
occupies the top and the upper portion of the sides of the gravelly
oe -tidges between the arroyos, where exposure and run-off are maxi- :
ae mum. The soil is atte Pee gravel and ne 8 surface is generally a
oo es The Ch : th Pee 4 oe Pies by Chrysothamnus si
: _— Bigelovii and occupying the stare of the sides of the antes a
The soil 3 is generally adobe, often d and gravel.
tnd form eae ‘a. narrow fringe along the beds of arroy0s, which are =
mle sired wi ke ane tos :
: association, dominated by Fallugia poradoxa -
1917] MARKLE—ROOT SYSTEMS 181
many are necessarily incomplete. It was found possible to photo-
graph some of the larger perennials zm situ, but in general it was
found much more satisfactory to make accurate diagrams of the
horizontal and vertical extensions of the root systems on paper
metrically ruled in squares. The diagrams appear here drawn toa
scale of 1:20, except figs. 25 and 26. While in general only the
roots lying in or near a particular plane are represented, it was
generally found possible without much distortion to include the
most important part of each root system in both the horizontal
and vertical diagrams. Roots that for some reason were not
followed to the end are terminated in the diagrams by a broken
line. Roots turning to a direction at right — to the ne of
the diagram end in a dot.
CANNON divides root cians into 3 types: (1) a generalized
type, in which there is a well balanced development of both tap
and lateral roots; (2) a specialized form, in which the tap root is
-™Much the more prominent; and (3) a second specialized form,
characterized by a relatively better development of the lateral
roots. ee ; 5
insta That age dents
. Becetelle Wislizeni-—This lant a ee eS oe
: om the mets and to the actoyes. = consists of
relatively short tap root, with many strongly developed laterals
horizontally rather near the surface of the ‘soil. Some ae
of hens usually exceed the tap root in length. The specimen —
en
“oes I fe dt in ene gener ae an cI in .
182 BOTANICAL GAZETTE [SEPTEMBER
shown in fig. 2 grew in a moist situation, where the water of an
arroyo was impounded by adam. The plant is in its early spring
condition, the rosette having survived the winter. The root
system is of the generalized type. The laterals near the surface
are especially well developed, sometimes exceeding the tap root
in length. The specimen shown in fig. 3 is from a dry, gravelly
ridge in the Dysodia-Ephedra
association. The impoverished
condition of the plant is shown
by the weak development of
both root and shoot. Here the
tap root is relatively the more
important.
Allocarya crassisepala.—This
is one of the most common
annuals of the mesa and
arroyos and is a ruderal in a
number of associations. The
plants vary very greatly with
the soil conditions in both root
and shoot. The plant shown
in fig. 4 grew in moist soil in
the bottom of an arroyo and
bore numerous prostrate
branches. The root system
was superficial and consisted of
a short tap root which soon
“Fic. Biscutella Wislizeni «became horizontal, and -
number of long, b
laterals arising about an inch below the surface of the soil. The
‘plant shown in fig. 5 grew in dry soil and had a tap root relatively
= "hig a: and vertical, with poeta and less numerous
canescens. —This plant i is common ina number of a
1917] MARKLE—ROOT SYSTEMS 183
Linum rigidum.—This plant is characteristic of the Dysodia-
Ephedra association. Both root and shoot are much reduced. The
root system in the plant shown in fig. 7 consisted of a tap root about
5 in. long and a few short laterals with almost no fine ultimate
branches.
184 BOTANICAL GAZETTE [SEPTEMBER
which later are deciduous. These always break off upon removal
from the soil and do not appear in the figure.
Rumex hymenosepalus.—This plant is common in the more
mesophytic places on the mesa, especially in broad, shallow arroyos.
The rosette of broad, thick leaves appears very early in the spring
and is soon followed by a spike of flowers. The root is very large
1917] MARKLE—ROOT SYSTEMS 185
Rumex is common in the arroyos on the mesa; Cucurbita foetidissima
occurs most abundantly along the banks of irrigation ditches in the
valley; Berlandiera lyrata is confined almost entirely to the sides
of arroyo beds. Thus it appears that the plants having this
“adaptation” to an arid environment are in less need of it than
most of the plants of the region.
Fics. 6, 7.—Fig. 6, Sisymbrium canescens; fig. 7, Linum rigidum
Astragalus diphysus and A. mollissimus——These are common
€vergreen plants of the mesa. The root systems are similar and
are characterized by prominent tap roots with a few large and
several small laterals, which are generally deeply placed. The root
tubercles are small and not numerous. A ae of A. mollissimus a
is shown in fig. 10. eS
Solanum eleagnifolium. This plant is very characteristic i ae
- sandy situations and the oS ee sides of arroyos. te
186 BOTANICAL GAZETTE [SEPTEMBER
plant shown in fig. 11 grew in the latter situation. The upper 12 in.
of soil was sandy adobe, followed by 10 in. of clayey adobe with
some gravel. Below this was a layer of loose gravel about 2 in. in
ickness, under which was fine sand to an unknown depth. The
plant was 18 in. in height. The root system was of the specialized
type with strongly developed tap root. There were a few well
developed laterals, two of which arose
at the junction of the layers of sandy
and clayey adobe. Upon reaching the
layer of loose gravel, one of these
turned abruptly and proceeded hori-
zontally in the gravel layer, possibly
tortuous course downward and was lost
at a depth of 65 in., below the level
3 mm., its total length was undoubtedly
- much greater. Numerous small laterals
arose in the upper 12 i in of soll.
Cucurbita foetidissima.—This per-
- ennial herbaceous vine is common along
irrigation ditches in the valley and less
so along the sides of arroyo beds. The
a i--Comiptone Fendleri_ root is extremely thick and fleshy and
is surmounted by an underground stem
6 in, in length. The ais Wook of the ea since was wan
ee 365) in. in diameter at the top and extended to a depth of 20 in.,
oe eg becoming horizontal and forking several times after
. ing a length foe in. The main root bore only one small
: ates (ig. 12).
Pa s
bus ~ ulus. This pai ten Babi ad is »
; d slopes of the gravelly
1917] MARKLE—ROOT SYSTEMS 187
irregular form, without evident differentiation into tap root and
laterals. The main root often proceeds horizontally and is little
larger than the minor roots. The specimen shown in fig. 13 grew
in pure gravel.
Euphorbia sp.—This small, prostrate plant grows on the sides
of arroyo beds. The root system has much the same general form
Fics. 9, 10.—Fig. 9, Rumex hymenosepalus; fig. 10, Astragalus mollissimus
as that of Sphaeralcea, but all the roots are slendex, brown, and
fibrous. The identity of the tap root is lost a short distance below S
the surface. The slender ultimate branches are very numerous.
The root system is not deep, but very ee | weareeeas 2.
limited amount of soil hei. |: vs
__ Sphaeralcea cuspidata.—This plant is very | comr Or
Bouteloua and pees edra associations. The plant
188 BOTANICAL GAZETTE [SEPTEMBER
fig. 15 grew in sandy soil on the mesa. The root system is charac-
terized by a tap root which is poorly differentiated or even absent,
and very prominent laterals. The remains of the crowns of several
years are shown. When the plant grows in an unstable situation,
Vv __ such as the rapidly eroding side of an
arroyo, vegetative reproduction from
the roots occurs very commonly,
enabling the plant to maintain a
foothold.
Berlandiera lyrata—This plant is
confined almost entirely to the sides
of arroyo beds. The root system has
a stout tap root with very few
laterals. The group of laterals near
the surface of the ground in so many
plants of the region is absent here.
The entire root system is thick and
fleshy and the upper portion is
swollen to the thickness of an inch.
Plant A, fig. 16, grew about 1 it.
_ above the bed of anarroyo. The tap
_ root divided into two horizontal ~
_ branches slightly below the level of
ie arroyo bed. Plant B grew about
4 ft. above the bed of an arroyo and
bore no extensive laterals until it
_ reached the level of the bed of the
\ arroyo, where it branched freely.
1 i - cei of the re root is —
cg : tance to - the layer of n moister soil Oe .
1917] MARKLE—ROOT SYSTEMS 189
the absorption probably being done by the ultimate branches of
the tap root. Vegetative reproduction from the roots is common
(fig. 17).
12 i
Fics. 12, 13.—Fig. 12, ertical ext 7 £ + cf. ee a re .
fig. 13, vertical extension on of root system of Packylophus hirsutus
mew em ee ee eee ee ee eee Se alietnettadt tt ie at ae aed aS ee wer ee ee
Igo BOTANICAL GAZETTE [SEPTEMBER
cactus type. Insome specimens no tap root could be distinguished,
although a better development of the tap root was found in plants
16
; 17
_ Fics. 16, ie 16, vertical extension of plants of Berlandiera lyrata: sical
growing 1 ft. above arro yo bed; 2. Singha above arroyo bed; fig. 17,
—— ee ee = Oe a a ee i
1917]
Fic. 19.—Vertical and horizontal
MARKLE—ROOT SYSTEMS
en]
-_-2e77
7"
=--°>"
ted
--""
-*
-*
one?
Fic. 20.—Root system of Ephedra trifurca
192 BOTANICAL GAZETTE [SEPTEMBER
was 28 in. in height. The tap root was weak, being exceeded in
diameter by several of the laterals. The laterals were numerous
and arose just below the ground and proceeded horizontally 2 or
3 in. below the surface, most of them beneath the bed of the arroyo.
The ends of several of them dipped abruptly downward. This
type of root is rare in the region. The root system of Parosela
scoparia, which grows
in sand, was found to
be similar, but more
deeply placed.
Artemisia tridentata.
—This plant grows
along the sides of
arroyos in the Chryso-
thamnus association.
Well developed speci-
mens are rare, since
the plant is freely
eaten by grazing ani-
mals. The specimen
shown in fig. 19 grew
in soil the upper 10 in.
of which was adobe,
overlying 12 in. of
coarse gravel and
Fic. 21.—Root system of Dysodia acerosum
oped, but the laterals near the surface were extremely prominent.
These were of two types: numerous short ones in the upper 12 in. of
soil, and a few very long ones which arose from the upper 6 in. of the
taproot. The latter proceeded horizontally 3—4 in. below the surface
of the soil and reached a length of 20-40in. There was a tendency
for the ends of these roots to turn downward, as in Parosela.
Ephedra trifurca.—This is one of the dominant species of the
_ Dysodia-Ephedra association. Investigation of a number of
Oe Se te om,
1917] MARKLE—ROOT SYSTEMS 193
specimens showed a considerable variation in the root system,
which in general has a good development of both tap and lateral
roots. The plant shown in fig. 20 grew in adobe soil about 2 ft.
above the bottom of an arroyo and had prominent laterals and a
stout but rapidly tapering tap root. Below the part shown in the
photograph, two large laterals were given off, below which the
tap root was insig-
nificant. Another
specimen growing
in adobe soil to ft.
above the bottom of
an arroyo and ex-
posed by erosion
showed a relatively
much greater de-
tap root. Several
laterals, the largest
alf an inch in dia-
meter, were given off
in the upper 2 ft. of
soil. Three small
laterals occurred
3 ft. below the sur-
face. The tap root
proceeded somewhat
tortuously down- : a '
ward to a depth of Fic. 22.—Root system of Chrysothamnus Bigelovit
at least 11 ft., a little
below the level of the arroyo bed, where a large lateral arose.
Below this the tap root had a diameter of 5 mm. and was not
followed farther. A third specimen grew ona hill and was exposed
by the removal of gravel. The plant grew in a soil composed of
boulders up to 8 in. in diameter, the interstices of which were a :
filled with sand. The root system was essentially similar to ie
second specimen described. The cause of the variation in the = i
appa ney is not t the c character of
194 BOTANICAL GAZETTE [SEPTEMBER
but the height of the plant above the nearest arroyo. Even though
there is a stream in the arroyo only a few hours each year, there is
probably a layer of moister soil on a level with the bottom of the
arroyo, on account of a slow creep of ground water toward the arroyo
and the conservation of the moisture by the dry sand covering it.
Dysodia acerosum.—
The habitat of this plant
is the same as that of
Ephedra. The aerial
parts of the plant form
a compact, much-
branched tuft. The
leaves are needle-like.
The individual photo-
graphed grew in sandy
adobe with large pebbles
(fig. 21). The plant
had a stout tap root
with a few large laterals
arising close together a
short distance below the
surface of the soil. The
tap root shown meas-
ures 39 in., but it was
probably several inches
aie longer. Both tap and
Fic. 23.—Root system of Opuntia fragilis lateral roots bore
numerous fine branches.
This species probably has the largest root system in proportion to
the size of the aerial parts of any of the plants of the region.
Chrysothamnus Bigelovii—This is the dominant plant in an
association characteristic of the lower parts of the sides of arroyos.
The principal photosynthetic work is done by the almost leafless
green stems. The root system is of the ne type. Fig. 22
shows only a part of the root system of a rath Later
excavation showed laterals up to go and 100 in. ». in length and a tap :
- root about roo in. ae eee te
1917] MARKLE—ROOT SYSTEMS 195
and taper very slightly and bear numerous small lateral branches,
especially near their distal ends. Older individuals probably have
root systems more extensive than that of any other plant of the
arroyos Or mesa. ,
Opuntia fragilis.—This is the smallest and most common cactus
of the mesa, where
large colonies form
mounds of sand or
adobe. The root
system is very
superficial and con-
sists of one or two
Main roots with
numerous small
lateral branches
(fig. 23).
Opuntia arbor-
escens.—This is the
only large cactus
found in the region.
mountains and
‘occurs sparingly
See ek a dae ee Ok ie
specimen shown in ia rae e
figs. 24 and 25
grew in the latter situation and was only 2.5 ft. i
root system is similar to the type described by (
larger forms occurring near Tucson. There i is a shar
tion of absorptive and anchorage roots. The forn
and thin and occur within an inch or two of the
196 BOTANICAL GAZETTE [SEPTEMBER
Opuntia camanchica.—This is the common prickly pear of the
mesa and arroyos. The specimen shown in fig. 26 occurred in the
Dysodia-Ephedra association in gravelly sand with small boulders.
The plant had been formed vegetatively from a fallen segment
which had become buried. The roots had originated from the
pulvini and the proximal 2 inches of each was tuberous. The root
system conforms to the usual superficial type described by CANNON
for the smaller cacti, except for the presence of one thick, deeply
* placed root. The plant is usually several joints in height, so that
Fic. 25- Ak tt +f ‘of Opuntia arborescens, } + tal extension
-_ -—
_ joint. The asic tah the thicke ,m placed d root may a
1917] MARKLE—ROOT SYSTEMS 197
formed by vegetative multiplication. The root system consists
of a thick, branched, horizontal portion bearing numerous laterals
quite uniformly about 3 mm. in diameter. Those measured showed
lengths of 5,6, 7, and 24in. The main root is usually about 2 in.
in diameter and very succulent. It evidently functions as a-
storage organ.
198 BOTANICAL GAZETTE . [SEPTEMBER
confined almost entirely to the space between the 16 and 24 in.
depths. The effect of the position of the plant with reference to
the arroyo bed is shown here.
Gutierrezia Sarothrae——This semi-evergreen shrub is a common
ruderal in many associations of mesa, mountain, and valley, but
especially on the mesa, where grazing has been a greater disturbing
factor. The plant shown in the photograph grew near the bottom
of an arroyo and had a root system of the generalized type. The
Fic. 27.—Yucca glauca
plant shown in the diagrams was a small specimen 8 in. in height
and grew near the edge of the steep bank of anarroyo bed. The tap
root was especially well developed and extended vertically to a
depth of 44 in., where it reached the level of the bottom of the
arroyo. Here the tap root turned and extended out under the bed
of the arroyo a distance of roo in., branching freely. The horizontal
part of the root was within 2 in. of the surface and bore numerous
fine absorptive roots. It is evident that the unusual development
of this root system is a response to moisture conditions, and it
is doubtless to this ability to respond to varying conditions that
1917] MARKLE—ROOT SYSTEMS 199
the plant owes its success as a ruderal in so many associations
(figs. 29, 30).
Atriplex canescens.—This evergreen shrub is common on the
fans at the mouths of arroyos and less so along the sides of the
smaller arroyos. A small plant 18 in. in height and growing in a
small arroyo was selected for excavation. The upper 15 in. of the
soil was sandy adobe, underlaid by 32 in. of coarse sand and gravel
and 15 in. of hardpan. The plant had a strong tap root which
forked at a depth of 32 in. One branch continued vertically
downward and penetrated the hardpan layer. The other branch
Ais
mwweeeen ww +e ee we we ee ee ee
ee cee eee te tee ede cece weet ts ee
Cs) eae eek we ee pe 2 ee 8 oe
Fic. 28 a, 7 Se ee, een * - 4 me ff oT. wo.
. le j
root penetration was evident fom the twisted character of the )
fonts es 32; 32, 33): os :
(|. dycum pallidum.—This solana eo
— [ane Heiiho ee mie TOY oye yo
200 BOTANICAL GAZETTE [SEPTEMBER
A few laterals may extend upward. The main root of a specimen
18 in. in height was followed along the face of a steep bank for a
distance of 15 ft., at which point the root was a quarter of an inch
in diameter. The superficial character of the root system makes
possible the vegetative multiplication by which the plant maintains
itself in its unstable habitat. Erosion exposes the roots, which
, put forth new shoots.
Discussion
On account of the
fact that here, where
the soil is of fluviatile
origin, the conditions
to which roots are
exposed vary so much, —
even within the habitat
determine. Variations
are common, but they
may be due to one or
more of a large number
of soil factors, such as
the composition of the
soil, its penetrability,
‘Fic. 29-—Galierrezia Sarothae from near bottom its alkalinity, its wilt- : .
: of arroyo.
ing coefficient, etc.
roe problem of the causes of root variation is one to be attacked
lition: ssa huasasic one factor can be varied at :
ne Pees ane made apparent the effect of at least two a
1917] MARKLE—ROOT SYSTEMS 201
eleagnifolium, shown in fig. 11. A layer of soil difficult of penetra-
tion may cause much distortion of roots entering it, as seen in the
diagram illustrating the roots of Atriplex canescens.
The most striking instance of the effect of a variation in the
water content of the soil is shown in the roots of plants growing
along arroyos. Nearly all of these are characterized by long tap
roots, the length of which apparently is determined by the height
of the base of the plant above the moister soil below the level of the
i i
<. e G
See tT mms,
s,
‘
'
'
'
'
Mo
mee :
ie
ec et
“S cy pete tae ae, - . ec. nas me ge ot
: Fic. iG. 30. 5) pee Y y
Career Se
202 BOTANICAL GAZETTE [SEPTEMBER
the widest distribution, while those with the specialized types are
confined to peculiar habitats.
Gutierrezia Sarothrae, which has a generalized root system, is
very widely distributed in primitive growths and as a ruderal.
A number of species are confined here to the sides of arroyo beds
and are characterized by prominent tap roots. Lycium pallidum
has prominent horizontal roots and is confined almost entirely to
rapidly eroding banks.
he ee em ee we on -
Oe ay
: >
: ~—=F
:
a
- iy :
XT. 4 . :
—s 31. rt y
=e. 5 oe ey ate. © gens
cred,
; Contrary to what
_ the most fleshy roots grow in situpiions s better watered than the
average. Cucurbita foetidissima grows near irrigation ditches and
_ along arroyos; -Rumex hymenosepalus occurs in the broad arroyoS
a ‘crossing the mesa; Berlandiera i is esas almost entirely to the i
me fe
=) wy.
1917} MARKLE—ROOT SYSTEMS 203
is very prominent. A comparable adjustment of the roots of
plants with reference to soil moisture probably exists in all types
of associations, but especially in arid habitats soil moisture is a
limiting factor and root competition is more severe. Observations
of the distribution of the roots of some of the associations were made
on rapidly eroding arroyo banks and sand and gravel pits.
In the Bouteloua association, the most superficial layer of roots
is that formed by the grasses, principal among which are Bouteloua
ertopoda and Hilaria Jamesii. Most of the roots of these grasses
occupy the upper 2 in. of soil, although some of them go much
deeper. The roots of Hilaria are very tough and woody and reach
a length of 6 ft. or more. The thorough permeation of the upper
Fics. vit ss Fe 3% horizontal extension of root System of rie canescens
at depth of
ele A eae a aN
for the relatively pure growth of grasses in this association. They
so thoroughly remove the water from the superficial layer that
seedlings of deeper rooted Plants perish before the lower, moister a
_ layers are penetrated. Over larg ae
Sg ke aS eT BEI
: ruderals ane £7..85
ih the Dysodia-E phedra association, th
204. BOTANICAL GAZETTE [SEPTEMBER
A second region of root penetration is occupied by the relatively
superficial laterals so common among the plants of the region.
These in general are more deeply placed than the roots of the
grasses and annuals. Dysodia acerosum, Aplopappus, Euphorbia,
and Hymenopappus are the principal plants.
' A third layer of roots is made up of the lateral roots of Ephedra
and the deeper parts of the root systems of Dysodia, Allocarya
Jamesii, Pachylophus hirsutus, Melampodium, and others.
The fourth layer probably does not always occur, but near an
arroyo it may contain more roots than any except the superficial
layer. Here occur the ultimate branches of the tap root of Ephedra,
Gaura coccinea, Berlandiera lyrata, Stephanomeria runcinata, and
others.
The zonation of the roots reduces competition and permits the
growth of a larger number of species. The root systems of the two
dominant plants compete but little, since the principal absorptive
roots of Dysodia occur in the third layer and those of Ephedra in
the third and fourth layers. This no doubt accounts for the joint
dominance of the two plants.
Th t Albuqu liffers from that of Thaceoetin havind
aboek two-thirds as much rainfall and much lower winter tempera-
tures. ‘The soil of the mesa is fluviatile in origin and very
_ diverse in composition. The hardpan layer prominent at Tucson —
is not well developed. The winter annuals and the larger
shrubs and cacti are absent. Most of the plants are sponses oa
_ herbs. .
"The root systems poms penetrate rather deeply, but often
ae Mine prominent laterals near the surface of the soil. The cacti and oe
afew ot fici: J root system. Thelarger— -
u oS cacti show : a differentiation into anchorage and absorptive | eee Le
1917] MARKLE—ROOT SYSTEMS
While the causes of root variation can be accurately duterntned:
‘only under anbaratory conditions, two factors exert s wey evident
influence,
content. oe
The roots of the plants of association are grouped i
definite layers, so » that root - competition i is lessened. The
DEVELOPMENT OF SOME SPECIES OF PHOLIOTA
W. H. Sawyer, Jr.
(WITH PLATES XVI-Xx)
The taxonomy of the Agaricaceae at the present time is based
upon characters of the mature plant which in many cases are slight
and superficial and of uncertain homology. It is very probable
that a knowledge of the origin and method of development of the.
different structures composing the mature fruit body would aid
greatly in determining true relationships among the different
genera and Species, a ig is for this reason that a comparative study
of th lop t of the basidiocarp is important.
The first serious study in the Agaricaceae of the origin and dif-
_ ferentiation of the parts of the young fruit body began over half a
century ago, when HorrMann (19), in 1856, briefly described the
origin of the hymenium in Agaricus campesiris and two other
_ species. Four years later HorFMANN (20) gave a brief account of
_ the development of several additional species, in all of which the
hymenium was : Sangrpons in origin except one, Marasmius oreades.
- In 1866 D ¥ (13) studied the development of several species
of Agaricaceae, and his work was followed in 1874 by HartIc’s
(18) description of Armillaria mellea, BREFELD’s (12) work upon
Coprinus in 1877, and in 1889 by Fayon’s (15) very cursory study
of 43 species, with hymenium both exogenous and endogenous in :
_ origin. Nothing more was done along this line of research until _
: 1906, when ATKINSON (2) published a thorough description of the os
t of Age np A 1 the stimulus given by th :
- 4%. ne evide Se ee 1 ee
s by se ry eee Ee
a : tions on the development of “different agarics, a cee = oe
_ ALLEN (1), BEER (11), and FISCHER a (16). ee 8
= _Themateri forthe allowing investi 01 cc
-
1917] SAW YER—PHOLIOTA 207
rotten coniferous wood, presumably Picea rubra. Material of all
3 species was very abundant in several different localities, and in
each case the young stages selected were identified beyond the
possibility of a doubt by mature specimens associated with them.
An abundance of material in all stages of growth was fixed in
Carnoy’s fluid and carried into cedar oil before returning to Ithaca,
where it was imbedded, some in paraffin and some in collodion, and
sectioned for study.
Pholiota squarrosa
Young fruit bodies, in the stage of development shown in fig. 1,
are elliptical or elongate in outline and composed of hyphae loosely
interwoven in the basal region, but more compact toward the apex,
with some of the threads radiating from the summit. Scattered
through the tissue of the fruit bodies are hyphal threads, somewhat
straighter and more even in diameter than the ordinary hyphae,
which are Cepines because of het property of inking a very
deep stain. Thesed ly in the
youngest basidiocarps, but in successive stages of riage and
in all 3 species studied. Their function is unknown, but probably
they serve some special purpose in nutritio ‘ les oe has been
shown to occur in large q (Phallus, et al.) asa_
reserve food material, utilized during growth, ‘and it may be that >
these peculiar threads owe their deep-staining sci ea to ced )
presence of this substance. -
DIFFERENTIATION OF STEM FUNDAMENT. in the ‘frait bly
shown in fig. 1 a small, deeply staining area occurs in the central
and in
‘verve eal, the : ah
apical Part; this i is a region of active penth, with ee a c
fruit body. ‘This region marks |
would i in all probability be pacary :
fruit body,as shown in fig. 25 f ot peieinete
208 BOTANICAL GAZETTE [SEPTEMBER
described in Lepiota cristata and L. seminuda (10), in species of
Cortinarius (14), and in Rozites gongylophora (22).
In further stages of development, the hyphae in the stem funda-
ment, by interstitial growth, form a compact, broadly conical area,
whose apex is the dark-stained region and whose sides in median
longitudinal sections slope outward at a strong angle (fig. 8). The
hyphae pursue a rather uniformly longitudinal direction of growth,
and are rich in protoplasm; the peripheral threads, because of this
longitudinal arrangement and their deeply staining qualities,
delimit the surface of the stem from the enveloping ground tissue,
whose hyphae are poor in protoplasmic content and without definite
direction.
DIFFERENTIATION OF HYMENOPHORE AND PILEUS PRIMORDIA.—
During an early stage in the differentiation of the stem fundament
there appears, in median longitudinal sections, in the ground tissue
on either side of the apical part of the fundament, a small mass of
hyphae, which is readily distinguishable from the surrounding tissue
because of the compact nature of the hyphal complex and its
property of taking a deep stain (figs. 4, 7). Serial longitudinal
sections show that these hyphae occur in a ring around the apex
_of the stem primordium; they are the earliest evidence of the dif-
ferentiation of the primordium of the oo The appear-
ance of th he fundament _
one: the pileus from the stem fundament, although as sae the tissue
composing it is very loose and hardly to be distinguished from the _
a — ground tissue. The individual hyphae that make up
i grow down from this area; at first =
| | they are crowded, very rich in protoplasm, and run in every direc-
ee 6). As = 4
, the — aor out
nor i mo eve
are slightly more slender, averaging abeat
i917] SAWYER—PHOLIOTA 209
in the hymenophore are slender and somewhat pointed; they show
a tendency to aggregate themselves at the tips into groups or tufts,
with the ends of several hyphae in each tuft, and the different tufts
separated by narrow interstices, so that the primordium often
presents a rough and jagged appearance in this stage of its develop-
ment.
BLEMATOGEN.—In the youngest fruit body sectioned (fig. 1)
the universal veil consists of hyphae which push up at the apex and
turn downward in all directions. There is little doubt that if
younger stages had been available for study, a condition would
have been found similar to that in the very young fruit bodies of
P. flammans, where the hyphae in the beginning are loose and
radiate from all over the surface of the basidiocarp (fig. 24). In
the stage shown here, however, the development has proceeded to a
condition where the hyphae of the lateral surface of the fruit body
have taken on a direction of growth parallel to the axis of the stem -
fundament; a central core or strand of hyphal threads in the apex
grow upward more rapidly than the surrounding tissue, and by
curving backward and downward form a covering, which is the
oe Over the entire surface of the fruit body. The hyphal —
sei thus ¢ Sues ae outside become enlarged and ee :
ae Poke ae POSTS ey ae
are 3-5 u in diameter near the. base, and in —— region they — :
the hyphae of the blematogen layer pie ee sees: dag
. 8-15, # in diameter. The | cond dition anaepe here is Louie
: gen, a8 shown in fig. 13. a.
_ Formation OF PALISADE LAYER.— Following the stage when oo a
: ged it in irregular tufts, the hymenophore pri
re ompact ie ie ees eee of ae
210 BOTANICAL GAZETTE [SEPTEMBER
apex, and the two groups of threads grow into each other and inter-
mingle to form the common mass of the “volva.”’ In P. squarrosa
there is a material difference from the condition just described for
C. lagopus, since in this case there are no hyphae on the stem sur-
face which grow upward and unite with the downward growing
threads. Figs. 2, 3, and 7 show the central strand of hyphae just
mentioned; in fig. 5 the character of the blematogen hyphae may
be seen.
ORGANIZATION OF PILEUS.—Coincident with an early stage in
the development of the hymenophore primordium, median longi-
tudinal sections show that the fundament of the pileus is becoming
differentiated from the surrounding tissue (fig. 8). The hyphae
become richer in protoplasm and by interstitial growth form a more
compact structure. This organization proceeds from the center
outward in a centrifugal manner, the margin of the pileus keeping
pace with, and contributing to, the growth of the hymenophore
primordium. During the early stages of differentiation of the
pileus some of the hyphae arise from the stem, but its later growth _ :
is probably due entirely to interstitial and marginal increase of its
own elements, which are interwoven in all directions, thus differing
from the hyphae of the stem, which in general run parallel to the
stem axis. The pileus elements merge gradually with the blemato-
gen and there is no sharp line of division between the two struc-_
tures. The cells of the blematogen hyphae, however, are swollen
and have thick walls, which stain deeply, while the pileus hyphae
are slender and do not take a deep stain after the pileus is well
Organized, so that a general distinction is evident. In ens ae
ie peripheral threads of the eases ‘composing. = ote
i
1917] SAWYER—PHOLIOTA 211
pileus margin at this time is turned downward and often somewhat
incurved as a result of epinastic growth, and lies nearly parallel
with the surface of the stem, which still slopes outward at a slight
angle (fig. 10).
FORMATION OF ANNULAR PRELAMELLAR CAVITY.—During dif-
ferentiation of the young basidiocarp some ground tissue is left
below the hymenophore primordium in the angle formed by the
junction of the stem and pileus fundaments. In later development
this ground tissue increases to some extent by interstitial growth,
but the more rapid growth of the stem, hymenophore, and pileus
subjects it to tension, and it very early becomes loose in texture
(fig. 4). As the stem elongates and the pileus broadens out, this
tension is further increased, so that the ground tissue becomes still
looser, with large spaces between the hyphae. At first it only
partially tears away from the surface of the hymenophore, and as a
result the gill cavity thus formed is weak, with strands of ground
tissue traversing it (figs. 13, 14, 16-20). The strength of the pre-
cavity varies in different individuals, as has been shown
to be the case in Agaricus rodmani (8); but in any case, in later
stages, but long before the gills are exposed by rupture of the
veil, the strands of ground tissue become completely broken away, __
and the edges of the lamellae are entirely free within the bl ae
cavity. ;
ORGANIZATION OF PARTIAL VEIL. the terms hleniati or
gen’
“universal veil” and “marginal” or “partial veil” have been
interpreted by ATKINSON (5), and are used in the same sense here.
The formation of the blematogen has already been described. oe
radial growth of hyphae in the apex of the young fruit body is very ae
___ Tapid for a time, and a thick layer is formed, enveloping the entire =
| Plant, but it is more dense i in the rupee region (Ges ro. ~~ .
- become i ps pero ‘Because = corns
: — Ast universal veil b mes subject to tet
212 BOTANICAL GAZETTE [SEPTEMBER
the ground tissue left in the angle between the stem and hymeno-
phore. This tissue increases, both by interstitial growth and by
the addition of hyphae which grow down from the pileus margin
(fig. 22). By the time that the gills are well formed this tissue
occupies a considerable area lying between the margin of the pileus
and the surface of the stem, and forming the floor of the gill cavity.
It is covered externally by the blematogen, with the inner surface _
of which its hyphae are interlaced, as some of them are with the stem
surface. .When expansion of the pileus occurs and the veil is
ruptured, it is left upon the stem as an annulate membrane com-
posed of two layers, the coarse, scaly blematogen layer below and
the partial veil above.
ORIGIN AND DEVELOPMENT OF LAMELLAE.—In a recent publica-
tion ATKINSON (9) has shown that in the Agaricaceae thus far
studied there are two types in regard to the origin and development
of the lamellae. First, the ‘‘Agaricus” type, in which the gills
arise by downward growing radial salients of the hymenophore,
accompanied or preceded by a more or less well developed annular
prelamellar cavity. Second, the “(Amanita’’ type, in which there
_is no general annular prelamellar cavity, and the origin of the
Tasman he Selo eeting Sore thy es
ment to the stem, and attached to siege P. sores obviously
se es he
: belongs tO the first type
: that in the course of development of ie jeune bak tas see oy
annular, prelamellar cavity, though weak, and a palisade layer are
fo
eo.
‘The origin and differentiation of the gills from the hymenophore _
e sea a ee
1917] SAW YER—PHOLIOTA 213
an imbedding material obviates the difficulty sometimes met with
in the use of paraffin, that delicate structures may be deformed or
dislocated by the heat of the oven or in spreading the paraffin
ribbons. Furthermore, the cutting of thicker sections, with a
sliding stroke, offers little chance for the displacement of structures,
which might happen in cutting thin paraffin sections. I mention
these points because some might suspect that the tearing away of
the ground tissue below the hymenophore, as shown in the following
figures, might be due to manipulation of the tissue, but such is not
the case.
Fig. 16 represents a section near the margin of the pileus; the
hyphae of the hymenophore are growing down in little tufts, and
at this time present a very loose, uneven surface. A considerable
number of hyphae from the ground tissue below may be seen
spanning the prelamellar cavity and united indiscriminately with
the downward growing tufts of the hymenophore and. with the
hyphae in the spaces between them.
In fig. 17, from a section a little nearer the stem, Sia. ioe
ophore on either side of the sectio presents the same loose, uneven
surface as in the preceding figure; but in the middle the hyphae
have enlarged at the tips and become blunt, and the ends have ~
grown down to form an even surface, the palisade, from which the — ae
_ ground tissue is almost entirely broken away. ‘The reason that the —
Palisade is in the middle of ped ete with undifferentiated tissue |
on either side, i: dil
sections, in pa
y hyrecnaphore in t the middle of the s¢
is in the form of a cece ar around the stem | apex, so that ang en
oe
214 BOTANICAL GAZETTE [SEPTEMBER
is completely free. That this ground tissue has nothing to do with
the formation of the palisade is shown by the fact that, as already
stated, it is attached indifferently to the hymenophore primordium,
and in many cases is largely broken away from the tufts and between
them before the palisade layer is formed. Furthermore, these tufts
of the hymenophore primordium are not the primordia of the
lamellae, since before the origin of the latter they become lost in the
even palisade (figs. 17, 18). In those instances where the ground
tissue remains adherent to the edges of the lamellae for some time,
and not to the palisade between them, it is due to the fact that
through the downward growth of the gills the strands of hyphae
attached to their edges are subject to less strain than the hyphae
attached between them, and so keep their attachment longer.
The downward growth of the lamellae may be partly initiated
by the pressure in the palisade layer due to the rapid growth and
enlargement of its hyphae, which would produce a tendency to
throw the palisade into folds.. The chief agency in their formation,
however, seems to be the downward growth of radially arranged
groups of hyphae in the hymenophore, which are very active in
growth at this time, as indicated by their deep stain. These radial
lines of deeply staining hyphae push down into the folds of the ©
_ palisade and form the trama of the gills (figs. rg-21). The further
_ growth of the lamellae in depth takes place by apical and interstitial
growth in the trama. Later stages in development (fig. 23) show
the hyphae from the trama turning outward on all sides to add to
ee et Oe lates ret ea
| : Pholiota flammans .
— OF BASIDIOCARP.—The very young ionlt: bois, =
efore any internal differentiation has taken place, is a compact
_ structure, composed of slender, intricately interwoven hyphae,
ae . ed H in diameter, and rich in protoplasm. The hyphae havea
__ general direction of growth away from the substratum n, and many
1917] SAW YER—PHOLIOTA 215
development of the blematogen, which is probably present from the
first appearance of the fruit body primordium.
DIFFERENTIATION OF STEM FUNDAMENT.—As_ development
proceeds, the hyphae in the base of the primordium take on more
active growth than the others, and by interstitial increase form a
very dense structure. This new area of growth, which is the stem
fundament, is shown as a deeply stained region in the base of the
fruit body in fig. 25. As growth continues, the cone-shaped stem
fundament advances toward the apex of the fruit body. In fig. 26
the most deeply stained portion represents the rapidly growing,
progressive apex of the stem fundament; the more compact tissue
below represents its earlier differentiated base; and the outer zone
of loose tissue surrounding the whole is the blematogen.
DIFFERENTIATION OF HYMENOPHORE AND PILEUS PRIMORDIA.—
The first evidence of the hymenophore primordium is the appear-
ance of a ring of compact, slender hyphae which surrounds the
upper part of the stem fundament and grows down into the ground
tissue, clothing the latter. The appearance of these differentiated
hyphae marks off the pileus area from the stem fundament. In
some cases the pileus fundament probably exists before the appear-
ance of the hymenophore primordium, as indicated by seg ape :
divergence of the hyphae from the apex of the stem fundament or _
by the more rapid growth in the region of the future pileus; “but
no sharp distinction can be drawn b 3 OF P
_and stipe u rig OFS 4°. rors eee +. atc Pa
An early stage in the development of the latter i is shown in fig. 30. _
As development continues, the pileus and hymenophore progress
Pedr in growth in a centrifugal manner. New ieneseg from
the pileus pease contribute to the hymenophore
takes plac ce e in +h 5 Oe oa
216 BOTANICAL GAZETTE [SEPTEMBER
it radiates from all parts of the surface as a loose aggregation
of hyphae with numerous interhyphal spaces (fig. 29). The new
elements arise chiefly in the apex of the young fruit body and extend
outward in a radial direction, curving backward as the fundament
of the basidiocarp elongates and as the stem and pileus primordia
are differentiated. This peculiarity of the blematogen is like that in
P. squarrosa. This downward growth continues until a thick cover-
ing is joumied (fig. $1). The elements of the blematogen are thick-
walled hat larger than the other hyphaeoi the basidiocarp,
but they are not caiasins globose, as in P. squarrosa.
Early in its formation some of the threads begin to break down
and gelatinize, and the universal veil soon becomes a gelatinous
matrix, imbedded in which may be recognized the remnants of
hyphae not yet disorganized. Such a condition exists in fig. 31, _
and a high magnification (fig. 38) shows a sharp contrast between
the gelatinized blematogen and the cortex of the pileus at this stage.
: very similar condition of the universal veil has been weaeis in
see oiget ambigua by ZELLER (25). |
The disorganization of the blematogen siosciente does not go
beyond the degree shown in fig. 38. Sections perpendicular to the
_ pileus in mature specimens show a very similar condition; there
is a gelatinous ground substance filled with dead hyphae whose
general course is parallel to the surface of the pileus. —— oe
sislonee rose part and the tension. exerted upon it by the
ig pileus the blematogen breaks up into scales. These
: POR differ very markedly, however, from the stout, pointed ~
scales of P. enemibees’ bad ie thin ¢ and aetente Je » more —
a iw FR er
wo id ‘ f P. a.
squares <
J & biidt UL !
e ring n € stem, as indicated i in - 2 -
epo’s Sylloge (23), in whic
=“) eae plant : : ;
1917] SAW YER—PHOLIOTA 217
formation in the preceding species. The ground tissue is loose from
a very early stage, and through expansion of the different parts of
the fruit body it becomes torn away from the lower surface of the
hymenophore. This separation from the hymenophore is com-
pleted at an earlier stage than in P. squarrosa, and consequently
a well defined cavity is present before the origin of the lamellae
(figs. 34, 37).
During the development of the hymenophore primordium and
the breaking away of the ground tissue below hyphae are growing
down from the pileus margin. These threads penetrate the ground
tissue below the prelamellar cavity and mingle with those on the
surface of the stem. In fig. 33 they may be seen curving inward
from the pileus margin. In the stage represented here they have
not yet reached the surface of the stem, and the loose ground tissue
surrounding the latter may still be seen between it and the advan-
cing hyphae from the pileus margin. These threads are sharply
contrasted with the other tissue of the basidiocarp because of their
Shs Salon, Which i tee aie nin ead os can ‘
addition, they may be distinguished from the blematogen external
to them by their deeper stain. These hyphae from the pileus —
, together with the ground tissue below the hymeno-
-phore, form the pattinl veil; it tears away from the stem at an
early stage in the expansion of the plant, and may in some
ee iculate
veil. —
: Onions AND DEVELOPMENT OF oe ola ad ae
i
the conditi P. squarrosa. Here we have ._
ridges. If no palisade c e differ
218 BOTANICAL GAZETTE [SEPTEMBER
been stated, the hyphae in the palisade layer are not crowded
enough to produce any great pressure, and it would seem that the
origin of the gill salients, which appear as downward folds of the
palisade, is due entirely to the growth and elongation of radial lines
of hyphae in the hymenophore, which push the palisade down in
folds, the young gills, as described for Hypholoma sublateritium (1)
and Siropharia ambigua (25). The gill salients are broader than
in P. squarrosa, and this may be due to the fact that when thrown
into folds by downward growth of the hyphae above, because of the
less crowded condition of the palisade, they are not subjected to as
great lateral pressure as in that species.
Fig. 39 is from a tangential longitudinal section of a basidiocarp
with sterile gills, that is, the palisade layer has failed to form. The
_cystidia, which develop from the trama of the gill, are very notice-
able as deeply staining clavate bodies. The situation presented
here is interesting because of its bearing on the question recently
raised by LevINE (21) in regard to the origin of the lamellae in the
Agaricaceae. The points of growth for the origin of the lamellae, as
described by ArkmNson in several species of the Agaricaceae,
including Agaricus rodmani (8) and Coprinus comatus, C. atramen-
tarius, and C. micaceus (9), occur in radial areas of hyphae in
the hymenophore, which develop centrifugally and grow down
more rapidly than the other hyphae. These areas are the gill
tramae, and push the palisade into regularly spaced folds, which
are the salients of the lamellae themselves. This method
here.
of origin of the lamellae occurs in the three species described
According to Levine’: S$ conception, radiating ridges of palisade =
cells arise in the fundamental tissue, and by continued differentia- ee
tion and downward growth of new palisade cells, split apart. Bee
adjacent halves of en come together and unite
to form a lamella. The trama of the gill would ee be formed by _
the coming together of preexisting palisade cells ae! ;
ee
ee eal) be formed. In this case, however, no
1917] SAWYER—PHOLIOTA 219
Pholiota adiposa
PRIMORDIUM OF BASIDIOCARP.—In the youngest fruit body
sectioned the mycelial threads grow out from the substratum to
form a compact mass of hyphae which are closely interwoven and
run in all directions. From this structure hyphae gradually assume
-an upward direction of growth, forming a papilla-like projection
(fig. 42), the fruit body primordium. The threads in the basal
mycelium from which the fruit body arises are very uneven in size;
those of the primordium are even in size, with free ends radiating
out all over the surface.
STEM FUNDAMENT.—The stem fundament probably differen-
tiates first in the base of the fruit body, as in the preceding species.
In fig. 43 its apex appears as a compact, dark-staining region near
the top of the basidiocarp, surrounded by the looser tissue of the
young blematogen. The fundament hyphae are very slender at
first, dense in protoplasm, and closely . running in all
directions.
PRIMORDIA OF HYMENOPHORE AND PILEUS.—When the hymen-
ophore and pileus primordia appear, the stem has become well
organized as a compact conical area, surrounded by the loose a
universal veil. The first differentiation of the pileusfundament be- __
comes evident through the growth of hyphae upward from the stem _
apex; these spread outward laterally, so that at this stage the :
stem and pileus areas together resemble a sheaf of wheat. At the _
same time some of these hyphae Deceane. subject to strong. epinastic :
growth, and curve down in g the
primordium of the hymenophore, which definitely | differentiates
‘the pileus area from the a m fundament. The gr pileus
continues b a ie si Sa a
ag —— broadens age by growth within 3 itself etted oo
2 The baliee of the ijineaopnase delendtien =a
gated ‘into. hier (fig. 48), as as in
- - still: re | attached — these
din tot
220 BOTANICAL GAZETTE [SEPTEMBER
species (figs. 45, 47). In later stages it loses this decurrent
character.
BLEMATOGEN.—The universal veil exists from the beginning;
its development proceeds very much as in P. flammans. At first
its hyphae radiate from all over the surface of the basidiocarp.
Later the growth of new elements is largely confined to the apex.
The peripheral cells become enlarged, thick-walled, with a diminu-
tion in protoplasmic content (fig. 52). The outer ones appear
empty and dead. Gelatinization takes place here, as in P. flam-
mans, but later, after the gills are well formed. Sections through
the mature pileus show that the blematogen has a structure very
comparable in the two species, in either case composed of a struc-
tureless matrix in which are imbedded dead hyphae, with a general
Hel to the p tface. At first disorganization occurs
only ower the pileus, but in the mature plant the gelatinization
takes place over the entire surface.
The mature pileus in P. fammans is dry, and in P. adiposa is
gelatinous or viscid. This difference is due to the fact that in the
latter species the disorganization of the blematogen elements pro-
ceeds farther than in the former, so that the walls of the hyphae
become more gelatinous, with a greater capacity for absorbing —
_ water. The surface of the blematogen breaks up into scales, as
in P. fammans, but the scales are very different in character. They . :
are not thin and fibrillose here, but in wet weather appear like
little lumps of jelly on the surface and are easily: lost, so that
it is not uncommon to find old fruit with the surface of ae
the pileus nearly free from them, especially over the central
the: ground tissue below the (sae making it loose, ee
spaces between the hyphae. At first, snes sof hyphae span the
to the hymenophore , but these have all
1917] SAWYER—PHOLIOTA 221
with some hyphae which grow down from the pileus margin. This
growth, however, is not as strong as in P. flammans. The partial
veil is covered externally by the blematogen. It ruptures at the
pileus margin during expansion of the plant, leaving a thin and
fugacious annulus on the stem.
_ ORIGIN AND DEVELOPMENT OF LAMELLAE.—The origin and
growth of the gills take place in this species much as in P. flammans.
The first evidence of the origin of the gill salients is the downward
projection of the palisade layer in broad folds (figs. 50, 51). A
single one of these broad folds includes several of the tufts which
earlier appear in the hymenophore primordium and become lost
in the palisade; consequently, these tufts cannot be considered as
gill fundaments or directly concerned in their origin. At the apex
of the folds the ends of the palisade cells may in some cases spread
slightly apart, showing that considerable pressure is exerted by the
downward growing hyphae from the hymenophore above. Under
no circumstances, however, do the gill salients show any evidence
of splitting; the hyphae merely spread slightly apart at the ends,
and in later stages come together again to form an uninterrupted
palisade. Serial sections show that the formation of the gill
salients is radial and centrifugal.
‘Figs. 53, 54, and 55 show a condition that might easily lead to z a ee
wrong interpretation of the origin of the lamellae by one not
familiar with the orientation of the parts involved. A simi
condition existing in Agaricus rodmani has been explained by
ATKINSON (8) and so will not be gone into in detail here. Te
sections are tangential in the margin of the pileus at a stage in Es
development when the pileus margin isenrolled. The attachment —
of the gill trama both above and below does not mean that the :
__ trama of the gill has grown down and pe as ee = oF
a as fie’ appear at “first glance. The pileus margin :
222 BOTANICAL GAZETTE [serremaun
Sequence of plant parts
The relative time of origin of the primordia of the basidiocarp is
of some historical interest. Fries (17), influenced perhaps by the
preformation theory, still in vogue in his time, believed that all
the parts, pileus, stem, and hymenophore, although indistinguish-
able, existed already formed in the young fruit body and unfolded
simultaneously. Scumirz (24) held that a successive formation of
new parts occurred; that the development of new parts rose
upward just as gradually as in the higher plants, so that those
stariding higher came into evidence later than those below; and
that therefore the matrix developed before the stipe, the latter
before the pileus, and the latter before the hymenium. Later,
Fayop (15) formulated a general law to the effect that the first
part to be differentiated is always the pileus primordium.
More recent work has shown that no general rule can be laid
down as to what primordium shall have precedence in differentia-
tion. In Agaricus campestris (2), A. arvensis (3), A. rodmani (8),
Armillaria mellea (4), and Siropharia ambigua (25), the hymeno-
phore primordium is differentiated first. In Hypholoma sub- —
lateritium (x), H. fasciculare (11), and Amanitopsis vaginata (7) the |
. pileus area is first outlined. The formation of the stem fundament
is the first differentiation to take place in Lepiota cristata and L.
seminuda (10), several species of Cortinarius (14), Rozites gongy-
lophora ids ~ the 3 species of Pholote described. :
Even in the same species y occur as to the relative :
of the different t primordia. ATKINSON (10) has"
shown this to be eine § in Agaricus arvensis (3) and Lepiota
: time of
clypeolaria (6). In P. flammans a would appear that the funda oe
ment of the pileus i nen
a primordium, and this may be true of the other two ‘species: a
ih all 3 species, however, the er of ~ sities o
1917] SAWYER—PHOLIOTA 223
peripheral region, and radiate from the entire surface of the fruit
bod :
y.
2. The blematogen is present from the first. differentiation of
the fruit body primordium, and in its earliest stages consists of the
loose, radiating peripheral hyphae. In subsequent growth it
forms a thick layer enveloping the entire plant; in’ P. flammans
and P. adiposa it becomes partially disorganized by gelatinization.
3. The formation of the stem fundament is the first differentia-
tion to take place in the young fruit body. It originates in the
basal part of the basidiocarp and by growth and differentiation
progresses toward the apex.
4. The primordium of the hymenophore is differentiated around
the apex of the stem fundament as an annular internal zone of new
growth. Frequently, before the hymenophore appears, a slight ~
divergence of hyphae from the ‘acini apex indicates differentiation
of the pileus. When theh dium is differentiated,
it marks off clearly the limit between the pileus and stem. It
consists of slender hyphae, rich in protoplasm, which grow down-
ward. At first the lower surface is uneven and loose, but by con-_
tinued growth the hymenophore becomes compact and the hyphae
grow down to the same level, forming an even: palisade area. ae
ies of the spose and es aeneee! of the _— — ee
1 I : - S ae 4 4
i * 3 ees
os. Th lar . ae
of the ground tissue f irom the low f. f tk 1 e, due :
to the tension exerted by the growth and expansion of the plant —
parts. It is weak in P. SNGITOS, @ as wen Femeet flammans —
oa and P. adiposa, bef As
224 BOTANICAL GAZETTE [SEPTEMBER
in these downward growing areas in the hymenophore, and the
first folds in the palisade are the salients of the lamellae themselves.
In P. flammans and P. adiposa the gill salients are very broad;
in all 3 species their origin and differentiation is centrifugal and
their subsequent growth is downward into the gill cavity.
In conclusion, I wish to acknowledge my deep obligation to
Professor G. F. ATKINSON, under whose direction this work was
done, for his unfailing interest and many helpful suggestions.
CoRNELL UNIVERSITY
Trmaca, N.Y.
LITERATURE CITED
1. ALLEN, CAROLINE L., The development of some species of Hypholoma.
Ann. Mycol. 4:387-304. pls. 5-7. 1906.
2. Atkinson, Gro. F., The deosaunect of Agaricus campestris. Bort. GAZ.
42:241-264. pls. 7-12. 1906.
+ -, The development of Agaricus arvensis and A. comtulus. Amer.
Jour. Bot. 1:3-22. pls. 2. 1914.
The development of Armillaria mellea. Mycol. Centralbl. 4:
_ 112-121. pls. 2. 1914.
» Homology of the universal veil in Agaricus. Mycol. Centralbl.
St13-10. p Bs. 13. 1914. ;
6.
pls. 13-16. 1914.
es denice! of Amanitopsis — Ann. Mycol. 12:
369-392. ve 17-19. 1914.
8. ————, Morphology and development at dissin rodmani. Proc. donk s
Phil. Soc. 54: 309-343.' pls. 7-13. 1915. 5
9- , Origin and development o yy ee acter Bor. Gaz.
&: soi oe as: Back cae
t Lepiots 7 vb pee, Ann. Mycol. ie dla bs is =
NY. Bot. Gard. 6: 1916.
ir. Beer,R oa one Joe Agari ae :
Ann. Botany 2§:683-689. m 52. 19rr. oe Ce ee
_-myceten + i. TT. 98-108. de a 1877. oe
1917] SAWYER—PHOLIOTA 225
15. Fayop, V., Prodrome d’une histoire naturelle des Agaricinées. Ann. Sci.
Nat. Bot. VII. 9:181-411. pls. 6,7. 1880.
16, FiscHer, C. C. E., On the development of the fructification of Armillaria
mucida Schrad. Ae Botany 23:503-507. pl. 35. 1909.
17. Fries, E., Systema orbis vegetabilis. 1: 1825.
18. Hartic, R. , Wichtige Krankheiten der Waldbaiime. 12-42. pis. 1, 2. 1874.
19. HorrMann, H., Die Pollinarien und Spermatien von Agaricus. Bot. Zeit.
14:137-148, 153-163. i 5 1856.
20. ———,, Beitrage zur t d Anatomie der Agaricinen
Bot. Zeit. 18: 380-305, 397, 404. pls. 13, 14. 1860.
21. LEVINE, M., The origin and development of the lamellae in Coprinus
micaceus. hat. Jour. Bot. 1:343-356. pls. 39, 49. 1914-
22. MOLterR, A., Die Pilzgirten einiger siidamerikanischer Ameisen. Bot.
Mittheil. Teen, 6:1-127. pls. 1-7. 1893.
23. Saccarpo, P. A., Sylloge Fungorum. 5:153. 1887.
24. SCHMITZ, J., Mycologische Beobachtungen als Beitrige zur Lebens- und
Entwicklungsgeschichte einiger Schwimme aus der Klasse der Gastro-
-myceten und i Linnaea 16:141-215. pls. 6, 7. 1842.
25. ZELLER, S. M., Development of Sieubberie ambigua. Mycologia 6:139-
145. pls. 124, 125. 1914.
EXPLANATION OF PLATES XVI-XX
The following microphotographs were made with the Bausch aad Lomb .
Ce ne Den eee ee ee ee .
of figure; oa leeplh
essa oe of cugoneble rating from summit; Laue
226 BOTANICAL GAZETTE [SEPTEMBER
portion of blematogen; at extreme right may be seen a part of hymenophore
primordium with loose ground tissue below; 56.
Fic. 6.—Left side of median section about the time when hymenophore
primordium is first differentiated; tangled, compact mass of hyphae of very
young hymenophore near center, with looser ground tissue surrounding it;
133.
Fic. 7 powan savant at about _ same ase of differentiation as fig. 4;
two compact, ; from summit blemato-
gen hyphae are curving cobnad and downward:
Phen 8.. Raucoug ee comical stem flea ieee hymenophore
pri ither cid
as a more Rae central area; loose ground tissue clothes stem, ‘and outside
is deep-stained blematogen; 18.
Fic. 9.—Tangential section of same fruit body; hymenophore primordium
appears as dark horizontal area, with uneven lower surface; i r dar
region just below is oblique section of stem surface; 18
Fic. 10.—Median section, sim ithge whit palisade het formed gill
avy Mbprars Ae & hence a almost closed because of epinastic growth of
-pileus ; below, the looser ground tissue; 133.
Fic. 11. a Veupeitial section of same fruit body; ground tissue is tearing
away from hymenophore to form gill cavity; above hymenophore is crescent-
shaped pileus, with the much thicker blematogen outside; X33-
_ fis. 12 -Higher mga ape of section near preceding to show blunt
low; above is dense hymen-
EE rag
Fic. 13.—Blematogen has broken into scales; stem and pileus are well
organized; b , ae | r ee
of ground tissue traversing it; dark line between pileus and hymenophore :
indicates area of more rapid growth; X13. aS
. piace seis nce pe caige ecotssi et 13, and showing same
features enlarged; X32. _ a
bt I i ~~ Pangential section, showing compact iyeuigins él no be -
nt hae not
t oi ay +O
oo become even in ey
o A. gr ee pe tare -Serial tang, eae tive nee :
hs 16 fynopore uneven an levity is weak _
ground tissue still attached to fips “id
1917] SAW YER—PHOLIOTA 227
Fic. 22.—Left side of median section in a stage waar mane are a
differentiated; at extreme left are hyph
into ground tissue below; knife has sé passed lengthwise through a : gl, ies
it thin enough to look through and see level palisade between it and next gill;
Fic. 23.—Tangential secti howing gills with t 1 palisade; 148.
PLATES XVIII, XIX
Pholiota flammans
Fig. 24.—Median section of very young fruit body, which is broken just
above peacatwe of rotten wood; loose, radiating threads represent early
stage in formation of blematogen; no internal differentiation has taken place;
X60.
Fic. 25.—Stem fundament forming in base of fruit body, its = ae stained
very deeply; outside is blematogen; 36.
Fic. 26.—Slightly later a in hicks by a growth, cere of stem
_ fundament has advanced to summit of fruit body; X36
les 27. —Somewhat — fruit sania with stem faunal differentiated,
rker area; very deeply stained, ee
are scattered through stem fundament; 36.
Fic. 28. Sane as fig. 27; X36.
Fra. 290 7 “18 eee
Fie. 209. St
Stem area well organized, but ho other differentiation X36.
fines 3o.—Small area on either side with looser ground tissue below repre-
= 31-—Stem and pileus areas well organized; } menophore st WS
228 BOTANICAL GAZETTE [SEPTEMBER
Fic. 35.—Tangential section, showing early stage in organization of
palisade by hymenophore; gill cavity below; 125.
Fic. 36.—Tangential section very near stem, showing two broad gill
salients, covered by palisade; some clavate cells of latter project beyond
surface, giving rough appearance; note disorganized condition of universal
veil; X86.
Fic. 37.—Tangential section, showing even palisade and large gill cavity;
31.
Fic. 38.—Section highly magnified to show contrast between pileus and
gelatinized blematogen; 142
Fic. 39.—Tangential ston of fruit body with sterile gills; note absence
of any palisade, and the cystidia, which develop from trama tissue of gill;
144.
Fic. 40.—Tangential section, showing normal gills at about same stage
as preceding; hyphae of trama may be seen turning outward to contribute to
palisade; cystidia are visible on edges of lamellae; 142
Fic. 41.—Tracheid of Picea inclosed in tissue of tps: this fruit body was
in advanced stage of development, with lamellae well differentiated; 230.
PLATE XX
Pholiota adiposa
‘Fic. 1G. 42.—Median section of very young fruit body; am ki aS
Sp ahmlinalinscaonmeRenaaEE threads radiating from surface 8
t 1 summit of fruit body; ™43- oe
og 45- . ee ix ow SDP ORAS Se stem and pileus are well organized .
and
hymenophore is forming palisade; heavy blematogen shows no signs of a
disorganization that occurs later; X18. oe
Fro, 46.—Tang a same stage in development; because 8
BOTANICAL GAZETTE, LXIV PLATE XVI
SAWYER on PHOLIOTA
PLATE XVII
AWYER on PHOLIOTA
BOTANICAL GAZETTE, LXIV PLATE XVIII
SAWYER on PHOLIOTA
BOTANICAL GAZETTE, LXIV FEATE XIX
SAWYER on PHOLIOTA
PLATE XX
BOTANICAL GAZETTE, LXIV
<<
Lae
©
ms
|
)
=
ew
c
a
ats
4
SAWY
1917] SAW YER—PHOLIOTA 229
_ Fic. 50.—Same, nearer stem; note the 3 slight downward projections of
palisade, which are very young gill salients; some ground tissue still clings to
them because their downward growth relieves tension upon it to some extent;
X67.
Fic. 51.—Section from same fruit body near stem, showing very broad gill
salients; 250
Fic. 52.—Large, thick-walled cells of blematogen; 250.
Fics. 53-55.—Sections tangential in enrolled pileus margin; fig. 53 (X33)
has not cut into gill cavity; ‘‘backs” of gills show as deeper stained areas; in
fig. 54 (X154) gill cavity is reached and gill is shown in middle with trama in
center and palisade on either side; its origin is in hymenophore both above and
below; fig. 55 (56) is nearer stem.
Fic. 56.—Tangential section, showing well-formed gill, with trama and
palisade; X154.
METHODS OF STUDYING PERMEABILITY OF
PROTOPLASM TO SALTS
S.C. BRooKs
Investigation of the permeability of protoplasm to electrolytes
has led to many apparent conflicts between evidence secured by
different methods and between the theoretical conclusions based
thereon. An intensive study of the evidence, and of the methods
themselves, has shown that these apparent conflicts are in large
_ measure due to an imperfect understanding of the limitations of the
methods or to unwarranted assumptions as to the nature and
reactions of living matter. It is therefore of interest to consider
critically the methods heretofore employed in the study of perme-
_ ability in order to determine which of these methods may be con-
sidered most reliable, and thus to acquire a broader understanding —
__ of the problem, and to lay the foundation for further investigation.
a _ The methods employed i in the investigation of the permeability
8 tes fall into 4 general categories, in which
a we criteria employed are: (1) chemical pase igh of tissue extracts
or of solutions bathing the tissues, (2) visible « es within the
= - (3) turgidity of cells or tissues, and (4) decesisl ‘conducts S
f tissues or of masses of cells. To these ‘may = added a diffusion
oS s ca
__ ANALYSIS OF TIssu
Chance mt by Js (0). " Filaments of a “species <3
1917] BROOKS—PERMEABILITY 231
then tested, gave no reaction. This method, although positive,
can yield only qualitative data.
As a method for the investigation of protoplasmic permeability,
quantitative analysis of tissue extracts involves several important
sources of error, among which may be mentioned the presence of
salts in the intercellular spaces and in the cell walls, where they
may be held in solution or by adsorption, variations of the con-
centration and constitution of expressed juices dependent on the
pressure used in extraction (cf. MamELI 30), and, most serious of
all, adsorption or chemical union of the salts within ‘the cell. Thus,
while aluminium ions might displace potassium ions in an adsorp-
tion compound, sodium ions might displace the Sapien ions to a
small extent only. In this way the free aluminium content of the
cell would remain low, and the original rate a endosmosis of
aluminium salts would be maintained, while that of sodium salts
would steadily deorease as the free sodium-content of the cell
increased. A similar effect might be produced by the formation of
hydrates of aluminium and sodium; the former being insoluble
would form a precipitate, while the latter would sain in solution." -
The relative permeability of the t would then
be made to appear other than it actualy wie The last error also |
affects methods involving the amount of salt taken by tissues from
by experiments of this type, such |
- PP. 453 ff.), PANTANELLI (51), DE Rurz: DE ‘LavIson el 56), Count
and DE Rurz DE Lavison (4, 5), M (EURER (36), and many others. :
PAINE (50), usi , drew the conclusion that yeast
\a™s : = Doce aie 7 . ie
cells are wholly i able to i Jif i ~ Its.2 eeeg! a x ae
absorption of oe salts nates the yeast cells, b
n pagilaieag cmaeyners
232 BOTANICAL GAZETTE [SEPTEMBER
ANALYSIS OF SOLUTIONS BATHING THE TISSUES.—The method |
of analysis may also be applied to the diffusion from living cells
(“‘exosmosis’’) of substances normally present in the cells and
retained by the impermeability of the protoplasm (they may
accumulate in the cell walls of terrestrial plants in quantities
sufficient to maintain a condition of equilibrium with the solution
inside the cell, and may diffuse out when the cells are placed in
water). Under certain conditions these substances may be made
to diffuse from the cells in appreciable quantities. The experiments —
of WACHTER (69) on the exosmosis of sugar from onion bulb scales
seemed to indicate that this exosmosis was inhibited by various
salts. In the light of more recent evidence it seems possible that
this was due to antagonization of traces of toxic salts in the ‘“‘Leit-
ungs-Wasser”’ which he used.
Other experiments have dealt with the absorption of salts from a :
the solution as well as with exosmosis. The results of the experi- oe
ments of TRUE (63), TRUE and BARTLETT (64, 65, 66), and MERRILL. —
(34, 35), like those of WAcuTER, were visible only after several -
hours, and the intervening effects upon permeability could not be
determined. There was also opportunity for Baa ckmmehs pro- .
cesses” and other complications to influence the tion of salts
to a marked extent during this interval, and a probability that Le
_ some of the external cells would be killed and would give off their A
contained solut lution. _Ttis quite prot bl :
that these effects are of importance in exper Ss
duration as those of the investigators mentioned. The most
serious objection to using the analysis of the i
im ents of such | Ca
of permeability i is that the ‘method does not disting lish - between
| difasng ov), it it will continue to diffuse i in, while a roubxtance which
-— Kations v was agree only to their physi
expected of periments of lo
1917] BROOKS—PERMEABILITY 233
increased exosmosis may be due, not to increased permeability,
but to increased production —_ the cell of the substance which
diffuses out.
Visible changes within the cell
This method, although sometimes valuable in the Servedtiontion
of the penetration of substances like the alkaloids which form intra-
vitam precipitates, and acids and alkalies which cause color changes
of pigments or intra-vitam stains, has found little application in the
study of the penetration of inorganic salts.
OsTERHOUT (39) showed that crystals of calcium oxalate form
in the root hairs of seedlings of Dianthus barbatus (previously grown
in distilled water) within a few hours after their immersion in dilute
solutions of calcium salts, and the subsequent normal growth of
the cells proved that they were not injured. ENDLER (7) followed
microscopically the entrance of intra-vitam stains (neutral red and
methylene blue) into various plant cells under the influence of
various kations. He also investigated the rate of disappearance
of the dyes from stained cells, living and dead. The experiments
are extremely instructive, showing that at 24 OF more hours the
Passage of dyes through the membrane was increased by kations- ie
in mie hate orters Na Dig E is |
ror7] BROOKS—PERMEABILITY : 237
carried far enough to cause plasmolysis, we have a means of avoid-
ing this objection. We may consider first those methods in which
plasmolysis occurs.
METHODS INVOLVING PLASMOLYSIS
1. Concentration Required to Produce Plasmolysis——DE VRIES
(67) noticed that the concentration of a glycerine solution just
concentrated enough to produce plasmolysis was higher than that
expected from the calculated osmotic pressure of the solution.
He attributed this to the penetration of glycerine into the cell.
On the assumption that an increase in the concentration of a
given substance required to produce plasmolysis indicates an
increase of permeability, LEPESCHKIN (23, 24, 25, 26) and TRONDLE
(62) claim to have demonstrated an increase of the permeability of
the protoplasm due to increased illumination; and EcKERSON (6)
seeks the cause of the thermotropic curvatures of roots in an
increase in permeability due to rise in temperature. By the same
method KREHAN (20, 21) has studied the effect of potassium
‘cyanide on the permeability of cells of Tradescanta discolor, the
_ experiments seeming to indicate that dilute sol 3 (0.001 M) of
potassium —, cause a temporar y and eve ible increase in
permeability, and hat t this is f jeg d rea: in p ea! if -
which begins si 4, ly ee eo be esibility. oe
"Oiseiaoee Cy aa t solutions of L cal os
chlorides, either of which alone is unable to prade !
(of cells of Gites Se sp.), may cause rapid plasmolysis when mixed
in such proportions that the ratio of sodium atoms to those cof se
cal chum is about 2 20 tot 1 $inc }
238 BOTANICAL GAZETTE [SEPTEMBER
This alteration he supposes to be the production of complete
permeability. Sztics (61) has since stated that the alteration
consists of a hardening of the protoplasm, since centrifuging no
longer displaces the cell contents. He also found the “hardening”
to be temporary, and to be followed by “‘reliquefaction.”
LEPESCHKIN (27) claims to determine with great accuracy, by a
method based upon the difference in the osmotic pressures of
isotonic plasmolyzing substances, the absolute rate of penetration
of these substances. It is impossible to explain the method clearly
and at the same time briefly, but its essential features are as
follows: a comparison of the osmotic pressure of a saccharose
solution which will just cause visible plasmolysis, with that of a
glycerine solution which, following the saccharose, will cause no
change in volume (as determined by LEPESCHKIN’s criterion) shows —
_ the latter to be the higher. If we let u represent a factor propor-
tional to the permeability of the protoplasm to the glycerine, and
assume that the protoplasm is impermeable to saccharose, then
| =e, » where C” is the concentration of glycerine found to be
isotonic with the saccharose solution, and C the concentration
calculated to be isosmotic with the saccharose solution. For
saccharose we may substitute any substance to which the proto-
plasm is supposed to be impermeable, and for glycerine any inkl 2
stance whose rate of penetration it is desired to measure.
This method would be exact provided the following assumptions —
were in accord with the facts: oe the prtogsm 5 is impermeable
to the control substance (in this case ; (2) neither of the
substances used causes any alteration i in the permeability of the
protoplasm; (3) no exosmosis occurs. All these assumptions are
_ rendered highly improbable by the evidence already secured by
_ other methods, and additional evidence against their validity will . -
. be submitted by the writer in a subsequent paper.
LEPESCHKIN also appears to assume that there is an effect on ss
me ie water equilibrium caused by the simultaneous age ee -
eee et he aed dependent
1917] BROOKS—PERMEABIL ITY 239
basis. The method of LreprscHKIn is therefore of extremely
doubtful value.
2. Recovery from Plasmolysis.—Recovery of plasmolyzed cells
was first noted by Kies (17) in 1887, who found that glycerine
was able to penetrate the plant cell. He was unable to detect
recovery of.cells plasmolyzed by solutions of potassium nitrate or
sodium chloride. Dr Vries (68) obtained similar results at about
the same time. JANSE (16), whose work has been quite generally
overlooked, demonstrated the penetration of potassium nitrate,
sodium chloride, and saccharose by observations on the recovery of
plasmolyzed cells of the marine algae Chaetomorpha aerea and
Dictyota sp., and Spirogyra nitida, Tradescantia discolor, and
Curcuma sp. It was thus conclusively shown that at least some
inorganic salts can penetrate living cells of many types of plants.
OVERTON (48) was unable to observe any cases of recovery of
cells plasmolyzed by inorganic salts. He supposed this to be due
_ to the insolubility of such salts in lipoid substances, which he
supposed to constitute the plasma membrane. It has been pointed
out by OstEeRHOuT (41) that OvERTON in all probability over- —
looked the recovery of the cells which he used, confusing the sub-
sequent “false plasmolysis,” due to the injury of the cells, for a
continuation of the true plasmolysis. OstERHOUT showed thata _
great variety of salts penetrate and cause recovery. OsTERHOUT _
also showed that the rate of recovery of Spirogyra cells was more
rapid when a salt of one of certain monovalent kations was used
to produce plasmolysis than when a calcium salt was similarly
used.* It was impossible to establish more than the most general
quantitative relations in these experiments. Recently Frrrmnc (8)
has conducted an extensive series of investigations on the per-
meability of cells of Tradescantia discolor L’Heritier (Rhoeo discolor
_ Hance). His data may be most easily understood if stated graph- :
ao ically. lates 8 strips of — were ae aks =
240 BOTANICAL GAZETTE [SEPTEMBER
abscissae concentration of the plasmolyzing solution would be a
straight line. It was found, however, that such a curve was
concave to the axis of the ordinates. This indicated a decrease in
the rate of recovery with time. Firrinc considers this to establish
the fact that such salts cause a progressive decrease in the per-
meability of the protoplasm. He considers the possibility that
exosmosis might have occurred in his experiments, and cites
experiments which supposedly show that all possible exosmosis had
taken place during the preliminary 4-6 hours’ exposure of the
tissues to distilled water. There are serious discrepancies in his
data, such as the fact that a solution of a higher osmotic pressure
is required to produce plasmolysis in tissues from which all possible
exosmosis is supposed to have taken place than is required to
produce it in otherwise comparable tissues from which no exosmosis
occurred. It is probable that Firrmnc has some important
variables in the method which he has employed, and since he has
failed to investigate the effect of salts of monovalent kations on
exosmosis, it is probable that the supposed decrease of endosmosis
is in reality an increase of exosmosis, which would have the same
effect on the rate of recovery. Firtinc also states that the cells
_are wholly impermeable to salts of bivalent and trivalent kations,
with the possible cP preiuea of strontium. This i is in conflict with
ai. = i i
METHODS NOT aoe PLASMOLYSIS
In rapidly elongating plant tissues there is usually a very con-
siderable pressure exerted by the protoplasts against the cell walls
which confine them. If all the cell walls of the stem are thin and
elastic, ay) whole stem will be kept i in a stretched condition by’ this 2 a
4 ae cells, ; such as fib ova: 01 la: oe -
- . or opal cells, which do not yield to internal pressures ieee eS
tissue. If we cut such a stem or aateneln aa € :
1917] BROOKS—PERMEABILITY 241
solution will withdraw water from the cells, and consequently
reduce the turgidity and the degree of curvature, while a hypotonic
solution will have the opposite effect. The penetration of the
protoplasm by a salt with whose solution such a tissue had come
into osmotic equilibrium would lead to an increase in the turgidity,
and hence in the curvature of the tissue. Dr Vries (67), in the
investigation of the isotonic coefficients of various substances by
this method, .observed such a secondary increase in curvature.
Such tissue curvatures have not since been used in quantitative
researches on the permeability of the protoplasm. The writer,
however, has found it possible to make use of this method for
quantitative determinations of permeability (BRooks 1a).
Changes in the volume or weight of animal cells or tissues have
been used by many investigators to determine the rate of penetra-
tion of electrolytes. Red blood corpuscles and striated muscle
have been the most frequently used materials.s As an example of
the former, the work of Kozawa (19) may be quoted. This
investigator added to 1 cc. of corpuscles centrifuged from defibri-
nated blood of various mammals 2 cc. of various solutions of equal
osmotic pressure (as judged by the freezing point depression).
corpuscles were again centrifuged after a time varying from
15 minutes to 23 hours, and the volume of the mass of corpuscles t
noted.® Increase of volume was c oe
of the solute. Sodium salts were not observed ne “cause. any =
increase in volume. nutes (8) made similar observations. oe
In some animals gl penetrate; in others it t did ae
‘not. It was found to be Sebi to influence the ermeability ne
to glucose by various agents, cone certain inorganic salts.
These conclusions agree with t ; is
corpuscles by su
unable to influence oa gee y - siden
242 BOTANICAL GAZETTE [SEPTEMBER
various hydrogen ion concentrations, or in solutions contain-
ing Ca, Mg, Mn, oxalate, or SO, ions (cf. also MasING 31 and
LOEB 28).
OvERTON (49) made successive determinations of the weight
of sartorius muscles of the frog during treatment with various
solutions. He reports that no increase in weight took place in a
0.7 per cent sodium chloride solution during a period of many hours;
that isotonic solutions of the phosphate, tartrate, sulphate, ethyl
sulphate, and acetate of potassium induced no change in weight
during 50 hours. After a few hours an increase of weight occurred
in solutions of potassium chloride, iodide, bromide, and nitrate,
but OvERTON found these changes to be irreversible, and concludes
that the normal muscle is impermeable to neutral salts. STEBECK
(57), on the other hand, finds that under proper conditions the
increase in weight of kidney tissue in a pure isotonic solution of
potassium chloride is reversible, and therefore considers that these
cells are normally permeable to potassium chloride. In general
the permeability of animal cells to neutral salts seems to be less, and
- more often characterized by selective peculiarities than that of
plant cells. The red-blood corpuscles, for example, may well be
considered to be surrounded by a considerably specialized proto-
plasmic envelope.
The experiments of Lor (29) on the permeability of fertilized
_Fundulus eggs to electrolytes are concerned with a peculiarly
specialized envelope surrounding the embryo. This envelope is”
characterized by an exceedingly small permeability to salts. Thus —
an embryo 4-14 days old within the egg membrane survives 3 days
of exposure to a solution (so cc. 3 M NaCl+x cc. 10/8 M CaCl.)
which is almost instantly fatal to the newly hatched fish. As has
previously been noted, generalizations as to the permeability of
_ protoplasm cannot be made from data furnished by experiments —
on such a membrane, and a more extended discussion of the results ,
of these experiments would not be profitable pete :
- Electrical I conductivity « of tissues or of masses 5 of cals
1917] BROOKS—PERM EABILITY 243
some substance. These charged atoms, known as ions, are not
created by the electrical conditions imposed, but already exist in
all solutions capable of conducting a current. The rate at which ©
the current will be conducted by the ions of a given salt will depend
upon two factors, the potential gradient and the frictional or other
resistance to the migration of the ions. If the potential gradient be
kept constant, we may follow fluctuations in the last factor by a
measurement of the current, or by a direct measurement of the
electrical resistance. If, therefore, we force the current to pass
through living protoplasm in a solution, the resistance offered by the
protoplasm to the passage of the ions will measure its permeability
to the ions in question (the permeability may be regarded as vary- .
ing inversely as the resistance). By the use of alternating currents
of rather high frequency we avoid large effects due to accumulation
of ions at surfaces impermeable to them.”
A method of this type was independently employed at about
the same time by R6rH (54), BuGARsKY and TANGt (2), and
STEWART (58), who found that the conductivity of blood serum was
greater than that of blood itself, and that the resistance rose rapidly
with increase of the proportion of corpuscles to serum. The blood
corpuscles seemed to be slightly or not at all permeable to the
electrolytes of blood. The conductivity of the suspension of
corpuscles was shown to be increased by haemolytic agents, the
corpuscles then being permeable to salts (cf. WOELFEL 70, also
STEWART 58, 59). McCieNpon has also attempted to study the
changes in permeability of sea urchin eggs during fertilization (32) _
and of muscles in tetanus (33). The evidence from his ——
ments on sea urchin eggs agrees with that of Harvey (12), previ-
ously mentioned, but difficulties in technique which McCLEeNnpon — |
found it impossible to avoid make the data of these experimer
exceedingly unreliable.
be experiments of OstERHOUT (42-47) 0 on the conductivity a : : :
. tissue of ene alga I Lami: tinct
. 244 BOTANICAL GAZETTE [SEPTEMBER
tion of the solution. The kations are of particular importance.
All monovalent kations (excepting the hydrogen ion) produce only
‘an increase in permeability of the protoplasm. This increase,
reversible in its first stages, finally leads to death and complete
permeability. Bivalent and trivalent kations and the hydrogen ion
cause a temporary and reversible decrease of permeability which is
followed or superseded by an increase which is irreversible and leads
to death of the cells. In a balanced solution such as sea water the
resistance remains constant provided the laboratory conditions are
such as to maintain the full vitality of the tissue. We have here
a method of determining quantitatively the permeability of the
protoplasm at any instant, and the data secured demonstrate the
extreme importance of progressive changes in the permeability of
protoplasm. It would be possible to imagine that the passage of
an electrical current through the tissues was responsible, at least in-
‘some measure, for the observed changes in permeability. It would
be of advantage, therefore, to check the results of OSTERHOUT’S
method by the use of some method entirely free from this possible
objection. The method is also applicable to certain types of tis-_
ever the actua
sue only, and it is desirable to extend to other types of plants the
principles derived by the application of this method.
The plasmolytic experiments of OsteRHouT (40) may be
explained in the light of the experiments by the conductivity method _
in the following manner. During the time required to produce
plasmolysis the permeability has considerably increased in the . .
sodium chloride solution and somewhat decreased in the calcium .
_ chloride solution. In that time much more sodium chloride has Le :
penetisied the cell, therefore, than of the salts of the mixed solution
in which the permeability remains normal, and these again more —
? S : than the calcium chloride, and the osmo: ic gradients -s have changed
accordingly. The osmotic pressures of the solutions which wil
- produce visible gens will then have suffered an increase
. ly i osmotic: solutions, and i in this order: calcium
“he — very. little, ¢ the mix ion slightly more. and d sodium oe
1917] BROOKS—PERMEABILITY 245
solution, the resulting osmotic pressure will be considerably above
that of a similar mixed solution (that is, one just insufficient to
cause plasmolysis), and plasmolysis will result.
Summary
From a consideration of the methods heretofore used in the
study of permeability it would appear that the steps most essential
to further progress toward the solution of the problem are: (1) a
‘thorough analysis of the various disturbing factors in the methods
involving chemical determinations and the satisfactory interpreta-
tion of the results secured by such methods; (2) the same type of
analysis of the methods depending on turgor, with special reference
to the Reon effect of emanate and (3) the establishment of
methods of d in ee without —
the various disadvantages of the other methods.
The writer hopes to show in subsequent papers that the dif-
fusion method, which he has devised, answers these requirements,
and that it is also possible to interpret satisfactorily the data
obtained by certain methods dependent upon the use of turgorasa
criterion. e oe
LABORATORY OF PLANT PHYSIOLOGY
VARD Universrry
eed jad pecan ‘Gai. Jour. Micr. Sti. sacs 1883. ee
a renee S. pica A study of permeability by the method of ‘tissue ten-
sion. Amer. Jour. Bot. 10: 562. T916. a ee a
246 BOTANICAL GAZETTE [SEPTEMBER
7. ENDLER, JosEPH, Uber den Durchtritt von Salzen durch das Protoplasma.
I. Uber die Beeinflussung der scope Teta in die lebende Zelle
durch Salze. Biochem. Zeitschr. 42:440.
8. Frrrmnc, H., Untersuchungen iiber die Aciniiee von Salzen in die lebende
Ze Jahrb. Wiss. Bot. 56:1. 1915.
9- Pui, M., Der Einfluss von Aluminiumsalzen auf das Protoplasma.
Flora 99:81. 1908.
to. Gydrey, P., Beitrage zur Permeabilitat der Blutkérperchen fiir Trauben-
zucker. OR Zeitschr. 57:441. 1913.
11. Hampurcer, H. J., Uber den Einfluss von Salzlésungen auf das vo
ee aes: Arch. Anat. und Physiol. 317. 1898.
2. Harvey, E. N., Studies on the permeability of cells. Jour. Exp. Zool.
10:507. IQII.
13- Hecut, Kart, Studien iiber den Vorgang der Plasmolyse. Beitr. Biol.
112137. 1912.
14. eae, S. G., Der Hamatokrit, ein neuer Apparat zur Untersuchung des
Blutes. Skand. Arch. Physiol. 2:134. 1891.
15. Henri, V., and Latou, S., Regulation osmotique des liquides internes chez
_ les Echinodermes. Compt. Rend. 137:721. 1903.
16. JANSE, J. M., Die Permeabilitat des Protoplasmas. Versl. Med. Kon.
_ Akad van Wetensch. Amsterdam, Afdeel. Natuurkunde. III. 4°332-
1887.
17. Kress, G., Beitrige zur Physiologie der Pflanzenzelle. Ber. Deutsch.
Bot. Gesells. 5:181. 1887. [.
18. Kozpre, H., Uber den Quellungsgrad der rothen Blutscheiben durch
jeculare zlésungen und iiber den osmotischen Druck des Blut-
Arch. hak. und Physiol. 154. 1895. oo
19. Ross, S. , Beitrage zum arteigenen Verhalten der roten Blutkérperchen. —
III. Artdifferenzen in der Durchlassigkeit der roten Blutkérperchen.
Biochem. Zeitschr. 60: 231. 64:
20. KREHAN, ae Ober die Wirkung des Kaliumcyanid auf die Permeabilitat
der P Lotos 62:752. 1914.
Se , Beitrage zur Physiologie der Stoffaufnahme in die lebende Pflan-
1917] BROOKS—PERMEABILITY 247
26. LEPESCHKIN, W. W., Zur Kenntniss des Mechanismus der photonasti-
schen Variationsbewegungen, und der Einwirkung des Beleuchtungs-
wechsels auf die Plasmamembran. Beih. Bot. Centralbl. 241:308. 1909.
27. ———, Uber die Permeabilititsbestimmung der Plasmamembran fiir
geldste Stoffe. Ber. Deutsch. Bot. Gesells. 27:129. 1909.
28. Loes, A., Beziehungen zwischen —— der Erythrocyten und
G hoes, Biochem. Zeitschr. 49: 413.
29. Logs, J., The mechanism of Hates sac action. Proc. Nat. Acad.
Sci. 1:473. 1915.
30. MAmett, Eva, Sulla conducibilita elettrica dei succhi e dei tessuti vegetali.
Atti Ist. Bot. Univ. Pavia II. 12: 285. 1908.
1. Masine, E., Sind die roten Blutkérper durchgingig fiir P ERennes £
Pfliiger’s echiv, 149:227. 1912.
32. McCLenpon, J. F., On the dynamics of cell division. II. Changes in
permeability of devslopiig eggs to electrolytes. Amer. Jour. Physiol.
272240. IQIO.
, The increased permeability of striated muscle to ions during
contraction, Amer. Jour. Physiol. 29:302. 1912.
34- MERRILL, M. C., Some relations of plants to distilled water and certain
dilute toxic soci. Ann. Mo. Bot. Gard. 2:459. 1915.
33-
35- ———,, Electrolytic determination of exosmosis from the roots of plants
subjected to the action of various ares tees Ann. pen aah eas
IQIS.
om R., (4g) eee <- Al 1. et. 3h
and C. Cramer. Heit I. erg
38. NATHANSOHN, A., Der Stoffwechsel uel
oe oe
39. Osrernovt, W. RY, ‘on the penetration of inorganic sls into ving ae
Petopinny. Zeitschr. Phys. Chem. 702408 tae
le and ie,
: tions. ‘Science N.S. 34:187. rorr. a oe
41. ———,, The permeability of pts tog and he hry io Pe
oe nism. Rilo Saber: og See Ae oe
“ — 1012. ae See
248 BOTANICAL GAZETTE [SEPTEMBER
46. OstERHOUT, W. J. V., On the decrease in permeability due to certain
bivalent kations. ee GAZ. 59:317- IQI5.
, The effect of some trivalent and tetravalent ions on pexmeshility.
Bot. Gan 59:464. I9QIS.
' 48. Overton, E., Uber die allgemeinen osmotischen Eigenschaften der Zelle,
ihre vermutlichen Ursachen, und ihre Bedeutung fiir die Physiologie.
Vierteljahrschr. Naturforsch. Ges. Ziirich 44:88. 1
47-
eitrige zur allgemeinen Muskel- und Nerveophysiologie Iil.
Stillen iiber die Wirkung der Alkali- und coeur auf Skelett-
muskeln und Nerven. Pfliiger’s Archiv. 105:176. 1
50. Paine, SIDNEY G., The permeability of the yeast 4 Proc. Roy. Soc.
London B. 84:289. 1911.
51. PANTANELLI, E., Uber Ionenaufnahme. Jahrb. Wiss. Bot. 56:689. 1915-
52. PRINGSHEIM, N, Untersuchungen iiber die Bau und die Bildung der
49-
Pflanzenzel
53- QUINTON, R., Permeabilité de la Sieti extérieure de l’invertébré marin,
non seule incat a l'eau, mais encore aux sels. Compt. Rend. — 952.
54. Rérx, W., Elektrische Leitfahigkeit thierischer Flussigkeite:
55- De Rurz DE Lavison, J., Du mode de pénétration de eas sels dans la
plante vivante. Rev. Gén. Bot. 22:225. 1910.
_—————, Essai sur une théorie de la nutrition minérale des plantes vascu-
laires. Rev. Gén. Bot. 23:177. 1gIt.
57- SIEBECK, R., Versuche iiber die diosmotischen Eigenschaften von Zellen.
Miinchener. Med. Wochenschr. 59:1126. 1912.
58. Stewart, G. N., Elektrischer Leitfahigkeit thierischer Flussigkeiten.
Zentralbl. ; Pioicl: 15:332. 1897. :
59- ————, The behavior of the haemoglobin and electrolytes of the colored
tions of decticlites to cells. Jour. SES and Exp. Ther. 1:49-
1909-10.
61. Sziics, yt ini kteristische Wi des Al
das Protoplasma. J Jahrb. Wiss. Bot. 52: 269. 1
62. TRénDLE, A., Der Einfluss des Lichtes auf die ane re der Plas-
mahaut. Jahrb. Wiss. Bot. goers IgIo.
63. True, R. H., The harmful action of distilled water. Amer. Jour. Bot. i
255. IQT4-
i R.H., and Barter, HL HL, Absor iat
= ant
aL cue a ee :
lecemer areas U.S. Dept. Agric. Bur. Pl. Ind. Bull. 231. — oo
——, The exchange of ee :
one ni nt salt. Tee 2:25 -
t917]
BROOKS—PERMEABILITY
66. TRUE, R. H., and BarTLett, H. H., , The exchange of ions between t
upinus d
BRIEFER ARTICLES
NOTES ON EFFECT OF DYES ON ENDOTHIA PARASITICA
Some experiments were made in growing the chestnut blight fungus,
Endothia parasitica, in a liquid medium to which stains had been added.
The dyes were congo red, trypan blue, methylene blue, and neutral red
plus 7 per cent NaCl, all “vital stains.”” They were added to a nutrient
medium, Pasteur’s solution. This solution was not a particularly good
one for the cultivation of the fungus. Congo red, trypan blue, and
methylene blue were used in 1/1000 of 1 per cent solutions. The dilu-
tion of neutral red plus 7 per cent NaCl was not known. This solution
had been successfully used in the vital staining of some animals of the
lower orders, and it was tried on the fungus by diluting it 1 cc. to 500 cc.
of Pasteur’s solution. The cultures were started from conidia mixed
with a little mycelium taken from a test tube culture.
Record of experiments
Conco RED (1/1000 of 1 per cent congo red! in Pasteur’s solution).—
Conidia germinated and produced normal mycelium. The hyphae
became red colored. When the cultures were 5 days old, hyphae and
—— had the same color. Reaction of moduay acid to litmus paper-
on +o pale Laiebeon. :
almost colorless, andclear. Th li s acid to lit
red colored mycelium which had been spreading steadily over the mote
of the medium showed in sharp contrast. Seven days later the fully and
normally developed fungus had produced pycnidia and conidia. The
1, and th ycnidia looked
yellow. Under the ‘microscope, the color of the hyphae was red to a
a opaque. The colored hyphae turned blue at once on being placed in oo
oF per cent sulphuric acid and later lost their color. The pycnidiaon :
being tested in sulphuric acid yerct reaction; some of — turned
o : phe, eneaid aoe Ot
. ‘Tryvan aioe (1/1000 of r per cent trypan? blue in n Pasteur’s ae
ce tion).—All the conidia, stained a - = so that their — wes could
1917] BRIEFER ARTICLES 251
be followed readily. They swelled, germinated, and produced normal
mycelia. The hyphae were a deep blue; the growing tips were opaque
to pale blue. Their blue color deepened with age. About 12 days after
inoculation the medium lost its blue color, turning light yellow; the blue
hyphae with uncolored pycnidia floated on its surface.
METHYLENE BLUE (1/1000 of 1 per cent methylene blue’ in Pasteur’s
solution).—The majority of conidia did not germinate, but instead
developed vacuoles. The hyphae produced did not stain, except when
the cells were dead. The plasmolyzed contents of the dead cells gathered
in a blue clump in the center. These isolated dead cells distributed
throughout the mycelium gave it a pale blue color. While the cultures
grew more vigorously than the controls, they did not grow as well as
the congo red and trypan blue cultures. No fruits were produced.
NEUTRAL RED (neutral red plus 7 per cent NaCl solution diluted
I to 500 parts Pasteur’s solution).—A few conidia germinated and grew.
The cultures were as good as the controls. No fruits. Hyphae un-
colored.
Controt (Pasteur’s solution).—Conidia germinated, produced
mycelium, but no pycnidia.
In the case of the congo red and trypan blue cultures, it was thought
that the mycelium had gradually stored up all the dye in the medium.
Neutral red and salt did not stain. In those cases in which methylene
blue penetrated the cells, it apparently was fatal. The fact that the
solutions containing the stains supported the fungus better than the
control medium seems to indicate one of two things: eithex. the toxicity. :
of the dyes in the conc used (with th Pp’ neutral —
red and salt) was enough tobe a stimul the dy h ter-
acted the elements in Pasteur’s solution inhibitive to the growth of the
fungus and so allowed the mycelium a better development. _
,* in a series of experiments with methylene blue, found
the dye accumulated in the cell sap rather than in the protoplast of the . :
cell. The substances which render the storage possibl
always identical; the two which are best known a are e tannin and _phloro-
glucin. Mycelium taken fi
Presence of tannin and premed ay "There was no evidence of these . a.
aed fear in the were cells. The eee —_ were ferric” :
rous sulphate bd bong potassium bi
252 BOTANICAL GAZETTE [SEPTEMBER
Mycelia growing in a congo red 1 to 200 parts maltose solution were
examined to see whether the dye had accumulated in the vacuoles or
protoplast of the cell. The mycelium had not behaved with methylene
blue as with the two colloids, but this gave no indication as to the deposi-
tion of the pigments. :
The fungus grew in the solution, but not vigorously. The mycelium
was so deeply stained as to be reddish black. Under the microscope
the conidia and older cells of the hyphae were dark red, while the youngest
cells were a pale pink. Treatment with 50 per cent nitric acid showed
by its blue colored reaction that most of the pigment was in the walls of
all the cells, only less in the younger cells. The hyphae were plasmolyzed
with a NaCl solution and also by drying; the contracted protoplasm in
the center of the cells was red, the cell wall looking white in contrast.
This first was noticed in the younger cells, the quantity of pigment in
the older cell walls having obscured the color of the protoplast, until the
‘last stages of plasmolysis had been reached. Sulphuric acid, nitric, or
hydrochloric produced besides a blue color, what was thought might be
_ a blue precipitate. These very small spots, seen with the oil immersion
lens, were on the cell walls and inside on the plasmolyzed protoplast.
Glycerin caused the color to stream from the mycelium. Sodium
hydroxide, while it brightened the red, also caused the color to diffuse
_ into the surrounding solution. Throughout all these reactions glistening
white granules in the protoplasts could be seen.
It would seem from these reactions that a great deal of the congo
red accumulated in the cell walls, some passed inside the cell walls, where _
it appeared as though the protoplast had stored the dye in the form of
minute granules. In the nutrient solutions containing congo red, the
difference in ee eeity of hing to store stain was so marked that con-
- ; t once. For instance, Penicillium sp., yeast,
and a rod-shaped bacterium f 1 growing in them remained unstained
until dead.
It is suggested that Endothia parasitica (Mur.) A. and A. may bea
- good subject for Se ee
ee us RUMBOLD, Pinter, al L
CURRENT LITERATURE
BOOK REVIEWS
The study of plants
WoopHeap’ has published an elementary textbook of botany which seems
to possess several features deserving better things than this tardy notice.
It is a pleasure to note that emphasis is placed upon the work of plants and
their relation ox the habitat. lpheiag is considered in relation to function, and
the amount f microscopic i juced t ini The book is divided
into 5 parts, the first ius Kea tela elk asivadto te
tative organs, occupying 150
cae ig organs, gr here, as as before, attention is confined to seed plants.
next 100 pa f the great groups of systematic
ete including a east consideration of trees and shrubs. The final
Portion is an introduction to the study of plant communities, inclding those
of the roadside and cultivated fields. One of th of the
book is the choice of so much material fr the common plants of the field
and wayside. It is a relief to see such Aarichrompentind vo iets
moka.
s0 persistently in moet textbooks. C [ee . gs
cipl as : nd pos es FURY SRE Re PRS that theexamples —
eaptlepeieece the British Isles, ee adda as ee
tunity of following wean tied rather than copying directly the —
outlined in the text. This < gs will certainly make the _
book indi. bl to the teacher in search - ideas and fi x exerci s :
with which to a
a It wo a kh. 3 3, a ce ; critic - id oat they ane not on oa
the whole serious defects. As an example, 7k ae oe ormal
SS ee oe
= o Cf
254 BOTANICAL GAZETTE [SEPTEMBER
‘The life of inland waters
This book? = eo — _ an i Connery 5 —— a comprehensive
view of our fresh forganisms. The
viewpoint is essentially ecological, ak a background of economic possibilities.
The first portion of the volume consists of an introduction to the subject, that
is to the science of limnology, including a historical sketch of important
in its development and a glance at the present facilities for study, which
include some 30 biological field stations in the United States and Canada.
There follows a discussion of water with respect to its transparency, tempera-
ture, and circulation, as well as its gas, mineral, and organic content. The
various types of — habitats are then presented. These include ponds,
and bogs.
, streams,
In the consideration of aquatic organisms, $7 pages are devoted to plant
and 83 to animal forms. Concerning the latter the reviewer will venture
no opinion, but the paragraphs on plant life seem interesting and accurate, but
so general that they would need to be supplemented by good teaching in the
field to accomplish their purpose. In such an ecological textbook the adjust-
ment of organisms to the varied conditions of aquatic life under which
_ exist, and the interaction of the aquatic communities are, of course, the most
; important parts of the book, and considering the immensity of the field to be
plexity of tl ial it would seem that the authors have
been very successful. Still the book will have to be supplemented by a teacher
with an unusually wide acquaintance with both plant and animal life in
to teach the entire field effectively. Good illustrations and a fairly extensive
bibliography add to the value of the volume.—Geo. D. FULLER.
MINOR NOTICES m
Fruit diseases—A recent textbook by Hester and Wanexsid discusses —
from
: _ the subject from an essentially New England viewpoint, omitting all ae
t are of : t in many states and : a
as
Na ht ar of nes or pel oem The decom
—
= “Nemo, Jos Game Loe, J.7 T., The lie of inland waters. “8v0. = 8 :
S. 244. ork: Comstock Co.
I viewpoint rather oS
=, ‘New York Botanic Garden. 1917.
1917] CURRENT LITERATURE 255
than of a general nature. This is especially obvious in the treatment of such
diseases as apple rust and pear blight. The illustrations are poor. Such figures
aS 29, 32, 40, 69, 76, 83, 86, 92, 98 are not worthy of publication. Throughout
the book there is a tendency to present various conflicting ee si argu-
ments concerning a given disease, with the result that often th
if any, are buried or obscured. This really is the result of the status of pathol-
ogy, of insufficient knowledge of the diseases in question, but the value of such
presentation to the student: and especially to the practical grower is doubtful.
sgtietg a central New York viewpoint and interest, the book may be said
0 give a very complete presentation of what is known of fruit diseases, with
saat lists of references to original sources of information. It is, as the
authors announce, the first American text to deal wholly with diseases of fruits,
and here for the first time are brought together with comprehensive discussion
many obscure and little-known diseases. The facts presented are well selected,
and the book — a valuable addition to the literature of plant diseases.
—F. L. STEVEN
North American Flora.—The second part of Vol. 21 contains the presenta-
tion of Amaranthaceae by. STANDLEY,‘ who recognizes 166 species distributed
among 21 genera. Amaranthus is much the largest genus, with 42 species,
followed by Iresine with 32, Achyranthes with 31, and Gomphrena with 15.
These | contain = Seagate 166 species, the remaining 46 being distrib-
uted among 1 era. w species, 10 in number, are described in Amaran-
thus (4), Aoi F scart Achyranthes, Gomphrena (2), and Iresine.—J. M. C.
North American Flora.—The second part of Vol. 10 contains the presenta- _
tion of Agaricales by Murritt, including the subtribe Pluteanae. The
largest genera are Entoloma (63 spp.), Pluteus (57 spp.), and Leptoniella” c
_ (43 spp.). Ten genera are presented, and 109 new species are distributed as
follows: Claudopus, Eccilia (9), Leptoniella (14), Nolanea Gx, Pleuropus (7),
Entoloma (34), Pluteus (30), Chamaeota, and Vela wnns @). J. M. c. es
: NOTES FOR STUDENTS _ ee
Anthocyans.—Since the review of the anthocyan (anthocyanin) moe
by Crocker,’ much # ee een ee
As ety out by C » these facts are of marked s e to ee
: ical, Gicaicat a oA on ee Se ae :
* STANLEY, Pak c, ‘North ie Flora ar: spart : 2 pp i i PORTS
a co a w. cent North . American Flora ro:part 4. - PP. a a ric le
256 BOTANICAL GAZETTE [SEPTEMBER
The bibliography is very complete and should stimulate further work. Brief
reviews of the anthocyan pigments have pegged appeared by Artxins;
Pveaesr, 9 encsamnrede SRI and WEst.”
ti ithe ugar-free compound, obtained
pon hy of th anthocyan with 20 per cent hydrochloric acid) has
He definitely established by the synthesis of cyanidin (by the reduction of
rectness of the formulas earlier proposed fy by sdeoevelien after studying the
orides. The mechan-
ism of the reduction of quercetin and other flavones to anthocyanidins has
béen questioned by certain Japanese workers,’ who claim to have isolated
various magnesium compounds as intermediate products. These criticisms,
Bonever, 3 in no way invalidate the general conclusion as to the structure of the
anthocyanidins.
me | Cl
0 O OH
wii Bee
Sas
HO
Cyanidin chloride
HO; oH.
_ S Argmys, W. R. G., Research hysiology. Whittaker Co. 16
a 9 Everest, A. E., Science Progress i507. 914-153 eg Genetics 4 es a
TOHETS. : es
_® WHELDALE we 1 red Cua Se ue
as: a. : Pog r ae a
1917]. CURRENT LITERATURE 257
The amyl alcohol test for anthocyans has played an mapesiant Part in the
course of WILLSTATTER’s work. The anthocyan (glucoside) remains quanti- _
tatively in dilute (2 N) sulphuric acid when shaken with amy] alcohol, whereas
the anthocyanidin (non-glucoside) passes quantitatively into the alcoholic
"layer, yielding a red solution. When shaken with a sdlution of a enone
the red color becomes violet or violet red, th
in the amyl alcohol. On shaking with sodiuia ‘carbonate, the alcohol solution
turns blue or bluish-green, and at the same time the pigment descends quanti-
tatively into the aqueous layer.
This is true only for diglucosides. Monoglucosides yield a certain amount ©
fas es Sc » the caaseedh ee Rhamnose glucosides (containing one
) behave like the monoglucosides. From
thie ss is seeks the test may be used to distinguish nome- and rhamnose-
glucosides from diglucosid
The test is also of service in testing the individuality of anthocyan. For
this the acid used must be of sufficient concentration to prevent the conversion
of the colored chloride into the colorless carbinol (W base) and yet must be
dilute enough to dissolve the chloride readily (0.5 per cent hydrochloric acid
Two successive extractions with amyl alcohol are made, and the fraction of the
sp aridcnin we mia agen Mace accia sere Scena wpe h ad
in both cases
: gi comprar: i solo ed
three classes were found. Iti true thatthe possiblity of other clases is, again,
not excluded. I
preliminary work 27
isolation of several new a anthocyanidins may be expected. The one flower
studied ed. however ae
ae ia ge pom nd and ni te S
: formula of chloride, the source from which it —S : fe
They ai
ad aan
258
BOTANICAL GAZETTE
[SEPTEMBER
The relationships of these various anthocyans and anthocyanidins may
best be seen from the diagrams on page 259.
TABLE I
Anthocyan Formula. Anthocyanidin Occurrence ‘Sugar components
Pelargonidingroup
largonin . CHx0.;Cl | Pelargonidin | Scarlet red pelar- | 2 glucose
2 C he
flower, orange
red and dark
os : violet dahlia
Callistephin....| CaHaOy.Cl . Summer aster i
‘Galvan. * i SUR oe
We. SS H,0,;C . Salvia es
Salvin......... CzHz0,;;Cl1 os i
Cyanidin group a
Cyanin... CzHO«Cl | Cyanidin Cornflower, rose, | 2 glucose
dark red garden
dahlia
| *Mono—or dimethyl ethers.
Eo DORE meer oF
‘+ + +
ek
_ eyanidin glucosides have been isolated from the cine cree blue
ete dP orSocasepteotise Aces of the flow .
1917] CURRENT LITERATURE 259
rubrum L., the raspberry, and the berry of the mountain ash. These glucosides
also occur very extensively in fruits and in yellowish red, red, brown, and dark
blue berries. They have been isolated from the cranberry, the cherry, the sloe
(black thornberry), and the plum. The occurrence of a pure red coloring
Pelargonidin group
Pelargonin Callistephin
Pelargonidin
Cyanidin group
260 BOTANICAL GAZETTE [SEPTEMBER
Haas” on this question. Determination of the total acidity and actual
acidity by means of titration, and the gas chain and buffer solutions, shows that
the reaction of the cells studied ranges from about Pa+3 to Pa+7. If we
call the buffer solution acid up to Pa+7, neutral when at Pz+7, and alkaline
when higher than Pu+7, it is evident that it is unsafe to call cell sap acid when
- red, neutral or alkaline when blue, and markedly alkaline when green, unless
the color changes of the particular pigment are first studied by some method,
such as that of using buffer solutions of known hydrogen ion concentration.
One other study may also be mentioned in this connection. These chem-
ical investigations inspired a study by Sarpata, Nacat, and Kisuma*™ of
the physiological and biological significance of the anthocyans and flavones in
plants. The evidence: obtained established a somewhat unexpected fact,
namely, that the flavone derivatives are one of the cell contents of very com-
mon occurrence in the plant kingdom. In fact, they are quite as common as
chlorophyll, tannins, sugars, starches, and proteins. They are not only found
ae He yebow Dosing wiatter, but also in the cell sap of the epidermis and in
the underlying tissu general jal: eal the
lete ab f chr for example, in the white corn flower
: (Centaurea cyanus), oxalis (Oxalis violacea), pink (Dianthus caryphyllus), and
(Pelargonium cucullatum). The function of the flavone deriva-
tives dissolved in the cell sap is to protect the living protoplasm and the
important biochemical agents involved from the injurious action of the ultra-
violet rays of sunlight by absorbing them at the peripheral layer of the plant
ihe plausibility of this assumption is justified by an extensive
study of th The green leaves of deciduous
trees, which produce anthocyan pigments in autumn, contain a co considerable
amount of flavones. The production of autumnal color is due to the bio
chemical change, that is, the red flavones in the leaf,
initiated by the physiological condition at the end of the growing season, with-
out having special ecological significance.
This brief survey of recent progress in anthocyan chemistry makes it seem
very probable: that i in the near future we may have a complete
based up dd f the chemical
. ‘arachos @ tad akieip ee aa Tt ie to be boped that the work say ee
any GEREN ea oe ee West.
"Taxonomic notes Evans” ‘has ‘published a monog! aph of the North
-
6 : bedi of Jama) sno. bolas = ten: — esc ae ue
of Marchantia, recognizing 9 aes one of which (M.—
1917] CURRENT LITERATURE 261
by an account of the morphology of the genus. The detailed description of
each species is accompanied by the synonymy, citations of exsiccatae, and.a
very full discussion.
In a revision of peace the same author™ discusses 4 species, 2 of which —
are described as new.
FERNALD” has described a new Cardamine (C. Longii) from Maine, which
grows in “shaded rock-pockets and crevices covered at high tide.” In the
description it is contrasted with C. pennsylvanica.
MacKenzie” has described a new species of Carex (C. convoluta), which
ranges from Maine to Manitoba and south to the Gulf States. Heretofore it
has been included in C. rosea.
PENNELL,* in continuation of his studies of the plants of the southern
States, has described a new Smilax (S. leptanthera) from Georgia, closely
allied to S. tamnifolia.
RENDLE* has described a new genus (Maidenia) of Hydrocharidaceae
from West Australia, belonging to the Vallisnerieae.
Rocx,s in connection with the preparation of a monograph of certain
genera of the Lobeliaceae of Hawaii, re oe et varieties
of Cyanea, and 2 new varieties of Lobelia.
Wrecanp* has described a new species of sects (E. peregrina), which
Occurs as a weed in this country, as well as in Germany and Japan, and which —
is unknown as yet in an indigenous state. It was separated from the well
a2 es segue a apd pape tre coe ron donee es
condensata Hackel.—_J. M.C. __
spore dete, Aree to ‘hae the ae as
of sporophores of
- rr cme igh ts
44:191-222. pl. 8. 1917. ce
“Pasa, M.A new Caromine rom stern Maine. odors 1898 -
92. 1917. —
ee 3 PENNELL, F. ful, Eeveaa en apeunems eRe
< Torr. Bot. Club 432412. 1916. :
- -* Renpie, A. A. By Maidens, «new genus of
2 eens ol. 545. 1916.
* MacKenzre, K. K. Notes on Carer. x. Bull. Torr. Bot. Club 431428. nea —
262 BOTANICAL GAZETTE [SEPTEMBER
some species of Fomes consists of true basidiospores which have been carried
upward by gentle currents of air, such as arise from differences of temperature
at different levels, and have lodged on the pilei. In support of this view the
author points out that other objects in the vicinity of the fungi also become
covered with spores. A simple experiment lends further support to this
view. Pieces of cardboard pinned on the surface of sporophores of Polyporus
applanatus in May were covered with spore powder in July, as were also. all
portions of the surfaces of the fruit bodies except the areas covered by the
paper. While not venturing to explain the pertinaceous adherence of the
spores to surfaces, the author suggests that they stick fast by virtue of a gelati-
— cutin layer. Regarding the spore powder on the surface of these fungi,
have generally adopted the view of ScHuLzER, according to which
the Sede consists of conidia whose origin on the surface of the pileus is -
minutely described by him. Although opposing the view of SCHULZER,
Romett does not speak of repeating the histological examination of that
investigator. If the explanation of RomeLt is correct, it is a matter for inquiry _
why this peculiarity of spore distribution is restricted to a few members of the
_ genus Fomes and does not occur more generally among the Hymenomycetes.
Even among the caespitose Agaricaceae, only those parts of the pilei over-—
=— by others are soely cat bs spores, while the exposed parts as
Journal of Forestry.—With the issue of January 1917 the Journal Ae
Forestry takes the place of the Proceedings of the Society of American eo |
_and of the Foresiry Quarterly. This change of either
a aspaige by the other, but rather an amaigamaton ofthe best feaeres of BE
: — “pages per annual volume.
ste ‘Original Publications i is intended. In continuing — the activities 08
wthath Soo to
the LAC YP WER WEE Oe
oe Te it mah fhe eu ts igh tna of
_ which promises well for its future. oe
oo ‘Some aig of 30 years of forestry work of the Federal Government P
1917] CURRENT LITERATURE . 263
It is safe to predict that the new journal will be of increasing interest
to all botanists, and more particularly so to ecologists who see in forestry the
practical application of their more theoretical studies —Gro. D. FULLER.
Endemism and the mutation theory.—WILLIS, in papers previously
reviewed in this journal,” working upon the flora of Ceylon, has proposed the
theory that relative endemism is determined by relative age, the youngest
species being the endemics. RIDLEY’ points out that Wituis has based his
arguments upon statistics gathered from herbarium specimens; and illustrates
that such will not agree with field statistics, the commonest species sometimes
being poorly represented in the herbarium. In connection with his theory
Witus States that “very common” plants could not disappear without a
i Rp
common species have disappeared within a few years, due to parasites, the
activities of ae and Eeavey: in climatic changes. Eoaae Gaines} a
the Ceylon 1
they could have been evolved recently.
The remainder of the paper is a criticism of the mutation theory as used
sea to explain the origin of the Ceyon flora. Rip_ey’s arguments and
theory, or WILLIS’ application of it, the paper is unconvincing to the .
reviewer.—MERLE C. CouLTER.
‘icin eld amis “Fincoe® tx Accs 4 Mecca ew ot
Norfolk and Suffolk Counties, England, where upon sandy soil with only 22.5
dominated
_ ovina and Agrostis vulgaris are the most abundant species. ‘The sterility lity of : o S
rere desta that some has never been cultivated and much of the restonce
o
ides is. a. i . es Great Britain
In the second of his Papers. the author finds that the chief factor in
: ae
264 BOTANICAL GAZETTE [SEPTEMBER
the Calluna maintains its dominance over both the grasses and the lichens. —
Geo. D. FULLER.
The variable desert.—Writing in semipopular language, Harris’? has
described the wide variation of climatic and other factors infloenchig plant
life in the desert region of Tucson, Arizona, in such a way as to give a more
graphic and living a - this most interesting region than will be found in
other more vol lreports. The wide variation of precipita-
tion from year to year and from month to month is made clear by a diagram,
while the large proportion of waste of the scanty water supply is emphasized.
The wide range of temperature during both the year and the day, the almost
urge: ‘qeeeed o pat forms, extending from thin to thick-leaved herbs, from
hrubs, and from succulent to woody plants with varied
aspect at different seasons of the year, are all clearly depicted. In a word, the
reader is made to appreciate some of the complexity of environment and
diversity of organisms which have rendered this region so fascinating to the
intelligent layman and to the investigating scientist.—Gro. D. FULLER.
: Ecology of lichens.—In connection with a systematic study of the lichen
flora of South Lancashire, WHELDON and Travis* discuss some of the factors
detrimental to the growth of these plants. Particular attention is directed
to their sensitiveness to pollution of the at ical
fumes attendant upon the development of a | mnautactacag industry. The
observations are of a general rather than of a particular character and are not —
—— by any experimental data. They also note that a calcareous
substratum ratum seems to counteract the effect of smoke upon the lichens. =
oe
4
baciciangh - scarier r
| 7 to the carboniferous limestone.—Gro. D. FULLER.
=r? ws?
rt ‘i... Ate L E ea tae sly OR ee st £.
: per commoner yas Ciedoagengeaaey Burns concludes that “‘toler-
ance: Uaed te experas.& light relationship should no longer be used in reference
te pment seedlings. He found the filtered light in the forest.
ee pea a es zy +s , nm di ide com i with the w k- og
. ened white light. in vay mau gh cp may
ge oe ae oe ae SORES 1 eS D.1 ig ‘
a J. Anruve, Ths tie st Scientific ¢ Monthly 341-49. 16 ee
33 WHELD A., and Travis, W. G., The lichens of South Lancashire. Jour
. Lina. Soe. airih 1QT5.
_eBems, GP, Std intolerance of New England forest is om
continuous light in forests. Vt Sta. Bull. 193. pp. 23- 191
VOLUME LXIV NUMBER 4
THE
BOTANICAL GAZETTE
OCTOBER 1917
_ NOTES ON BULBIFEROUS FUNGI WITH A KEY TO
DESCRIBED SPECIES
J. W. Hotson
(WITH PLATES XXI-XXIII AND SIX FIGURES)
Introduction
hs has been shown in a former article (6), the term bulbil, as
_ applied to fungi, refers to reproductive bodies of more or less
definite form, composed of a compact mass of homogeneous or
heterogeneous cells which may be few or many in number, but
which are usually developed from primordia of more than one
cell. This mode of reproduction is common among certain fungi -
and constitutes the only known means among others. Many
_ Of these structures superficially resemble the “spore-balls” of
_ Urocystis or Tuburcinia among the smuts, but differ from them in
their manner of germination. In general appearance and mode —
of development the bulbils of Papulospora spinulosa Hotson might —
readily be taken for “‘spore-balls”’ of Urocystis, but, on germination, ae
Promycelia bearing sporidia such as are produced by” the smuts are _ re
oe _yet unconnected with a perfect form are added to those a
266 BOTANICAL GAZETTE [ocroBER
Stephanoma strigosum Wallr. the superficial cells are produced in a
manner similar to those of certain bulbils. Mature bulbils may
also resemble sclerotia. The latter, however, may be regarded as
the result of the irregular massing together of vegetative filaments,
the individual cells of which do not partake of the nature of spores
either in appearance or structure, while in the bulbil those cells
that are filled with protoplasm usually act independently of each
other, in this respect resembling spores. There are a number of
sclerotia of the simpler type, such as are produced by Penicillium
italicum and its allies, which are small and more or less regular
in form and outline, somewhat resembling bulbils in appearance.
The mode of development of these sclerotia, however, consists in
the irregular massing together of the vegetative filaments, as has
just been mentioned.
Before 1912 the literature relating to bulbils dealt with less than
a dozen described forms. Most of these were referred either to the
form genus Papulospora or-to Helicosporangium. Owing to the
fact that the limitations of these two genera were not clearly defined,
it was thought wise to redescribe the genus Papulospora (6), and
to group all those fungi that produced bulbils, but whose perfect
condition had not been obtained, into this form genus. The
literature on this subject has been carefully reviewed in the article
already mentioned. This article shows clearly that these fungi do
not belong to any one of the natural orders, nor do they in any
sense form a group by themselves, but occur without regularity
as imperfect forms among the main groups of higher fungi. The
forms, associated with bulbiferous Sains mentioned in that
article, include among the Discomycetes a new species of Cubonia,
este the Hypocreales 3 species of Melanospora; among the ee
idiomycetes at least 4 types; while 9 species of Papulospora as — o
2 : pie Among the latter, Bie; ees. candida Sace. eee .
1917] HOTSON—BULBIFEROUS FUNGI 267
According to his account, the bulbils resemble the compound
spores of Urocystis among the Ustilaginales. The color of these
Urocystis-like spores is reddish to chocolate brown, their form more
or less spherical, the cortex being a layer of empty, colorless cells.
The size of the spore balls, however, is not given. They apparently
resemble the bulbils of Melanospora papillata Hotson, but the
perithecia of the two species are different. In M. marchica the
perithecium has no papilla, the setae arising from the flush surface
of the wall. The perithecium of M. papillata, on the other hand,
has a distinct and often quite prominent papilla, the terminal setae
being produced at its tip. The bulbils of M. marchica also resemble
those of Papulospora coprophila (Zukal) Hotson, but vary some-
what in their mode of development. Apparently NEcER had not
seen the writer’s article dealing with bulbils (6) or that of BAINIER
(x), and therefore makes no comparisons.
Recently DopcE (3, 4) has reported a species of Papulospora
closely associated with Ascobolus magnificus Dodge. He is of the
opinion that this is either a parasite on or an asexual spore form
of the Ascobolus. These bulbils are light brown, with a layer of __
empty cells forming the margin. A description of this fungus is —
0 in the present article under the name of Papulospora mag-—
fe has been shown in a recent article by Mexavs, RoseNpaum, 6
and ScHuttz (8) that a spec ing bulbilsis
' frequently associated with the powdery sc > of potatoes (Spongo- iS
Spora subterranea [Wallr.| Johnson). These investigators have
isolated P. coprophila (Zukal) Hotson from tubers infected with ee
— This organism has been shov F
experiments to be a anes arse a
268 BOTANICAL GAZETTE [OCTOBER
The substrata were put in moist chambers, and as the bulbils
appeared they were picked out with sterilized dissecting needles
and transferred to tubes containing nutrient material.
Description of species
Bulbils are in all cases to be regarded as imperfect conditions
of higher fungi. As has already been indicated, some have been
definitely connected with perfect conditions belonging to widely
separated genera of both Ascomycetes and Basidiomycetes. Those,
however, that are to be considered in the present article have thus
far baffled every effort to induce them to produce any perfect form,
even after 7 or 8 years of cultural study. Two of these are doubtless
ares since their mycelia possess clamp connections,
while sh me evidence that it belongs to the Pyrenomy-
cetes. It is the aim of the present article to contribute further
information regarding the occurrence, morphology, and develop-
ment of bulbils, and also to bring together the described species
in the form of a key to the genus Papulospora.
ospora pallidula, n.sp. (figs. 1-16; text fig. 2). —Mycelium
white, procumbent, scanty on most media; bulbils colorless, becom-
ing pale yellow when old, somewhat spherical, 70-100 » in diameter,
sometimes elongated to 1404; primordium of two kinds, one 4
short lateral branch which divides dichotomously of 3 or 4 orders, |
occasionally more, and the other a group of intercalary cells. No
other means of reproduction at present known.
On trois colearre oi Soe ane ete Gentoo and Claremont, California;
also on rabbit dung from Ontario.
The substrata were put into moist chambers and, when the
bulbils appeared, transfers were made, eventually producing pure
cultures. ee a
— ind Sead potas such as ue ae eas : :
1917] HOTSON—BULBIFEROUS FUNGI 269
is true with many other fungi, the abundance of the mycelium
depends largely upon the kind of substratum. On potato or goat
dung agar it develops very sparingly, often becoming quite difficult
to detect even with a good lens, while on bran or cornmeal agar |
it becomes more conspicuous, growing evenly over the whole sur-
face of the culture and on the sides of the tubes, but never becoming
very flocculent. On appropriate media such as horse dung, bran,
or cornmeal agar, the mycelium forms a thick felted layer over
the substratum. Most of the hyphae are small, about 3-5 u in
diameter, but some of the older ones become as large as 10 », with
prominent cross walls. They
are frequently packed with large
oil globules (fig. 1). Here and
there in the hyphae swollen
cells appear that are full of food
material. These are oval at
first, but eventually become
almost spherical.
DEVELOPMENT OF BULBIL.—
A short lateral branch divides
dichotomously, producing
dichotomies of the second, third, ©
or sometimes of the fourth order
(figs. 2-6). These branches
divide into short cells which
enlarge, eventually forming the central ones of the bulbil. As
these cells grow they become more compact, and from them by a
Process of budding others are formed which increase in size,
oming closely and compactly pressed against their neighbors
Fic. adeno preneaey ine,
(figs. 7-0). This mode of development usually produces mature
bulbils that phates Kah gus anieiiie magne ae URI So
70-100 mw in diameter (fig. 13). o —
_A second mode of develop ent of the bulbil is arenes os
270 BOTANICAL GAZETTE [ocTOBER
pale in color is formed, with several large cells in the center which
are conspicuously filled with oil globules. These bulbils are usually
more or less spherical, but not infrequently become elongated, as
shown in text fig. 2, which shows a group of bulbils, the longest of
which measures 78 by 140 uw and is probably the result of the fusing
of two immature forms. These bulbils germinate readily in water.
Fig. 13 shows a germinating bulbil 75 by 67.5 u in diameter after
24 hours ina Van Tieghem cell. The young hyphae, which have a
large number of oil globules, are usually produced from the larger
cells, but “y cell is capable of germination. Occasionally as
the bulbils grow older the cells
composing them adhere less
firmly together, becoming more
and more like indep
with the development of the
bulbil of Papulospora polyspora
Hotson (6), which in turn
suggests a similar condition —
found in Aegerita webbert
Fic. 2.—Group of bulbils of P.
pallidula. ae
few of these loosely con-
nected cells germinating, which seem to act independently, li |
spores :
His ‘eel that one of the primordia just described is that 2
of the perfect stage, but for some reason it fails to ae SS a
found, as if an effort were pelos: made sg the fungus to pr — ro ae
oS _ the perfect ain Thee far, Teapeee none > of these a ae
Faweett (5). Fig. 14 shows @
1917] HOTSON—BULBIFEROUS FUNGI 271
in form, 100-250 u, occasionally elongated to 350 in diameter,
produced in fluffy aerial clusters; primordium one or more short
lateral branches twining spirally about the main branch. No other
means of reproduction at present known.
On horse dung, Kittery, Maine; Seattle, Washington; St. Louis, Missouri.
The original material from which pure cultures of this fungus
were obtained was found on a horse dung compost at Kittery,
Maine, by Dr. Tuaxrer. It has since been found by the writer
on similar material in the vicinity of Seattle; also on material sent
from St. Louis, Missouri, by S. M. ZELLER. In the last instance
the bulbils apparently were produced after the horse dung compost
had been used as a fertilizer on mushroom beds. This fungus has
never been found on any other substratum than horse dung. It
has been grown on different media in pure cultures for 6 years
without inducing it to produce any other fructification than bulbils.
_ The mycelium is white, 3-5 u in diameter. It is usually pro-
cumbent, but when cultures are left in such a position that the
hyphae can grow straight downward they grow out into the air,
producing long streamers or festoons which attach themselves to
the opposite side of the test tube.
_ The bulbils of P. byssina resemble those of Grandinia crustosa, .
7 but the two species can easily be distinguished by the prominent
liut n of the latter. Even the general ae
appearance of the mycelium i in cultures i is sufficient to distinguish ©
them, Grandinia producing a) Cae tee et 1s, . i“ oe
Strands of hyphae which radiate conspicuously in all directioan ae
from the point of inoculation.” This phenomenon is entirely Boe
absent in P. byssina. The cells composing the bulbils are homo-
geneous throughout. In this respect ‘they resenible those | of 2 o
272 BOTANICAL GAZETTE | [OCTOBER
(fig. 17), which may send out other lateral branches near the first
(fig. 19). This branch may also take part in the formation of the
bulbil. The cells of these various branches increase in size and
become well supplied with food material. From them short
lateral branches are produced which either intertwine among each
other, or if very short assume the form of new cells as if produced
by a process of budding or gemmation. Fig. 20 shows the primor-
dium of a bulbil in which the secondary branches are being pro-
duced. These will eventually intertwine with each other in a more
or less wormlike fashion, as shown in fig. 21, an immature bulbil
44min diameter. The first lateral branches that twine around the
primary filament may become localized, in which case the mature ~
bulbils will be somewhat spherical, as shown in fig. 22, which
represents a bulbil 110 uw in diameter. More often, however, the
spherical bulbils are produced in a slightly different way. Not
infrequently a terminal branch coils up and winds back on itself,
or it may divide dichotomously, both branches thus formed twining
back on the main filament (fig. 18). A primordium of this sort
develops in the same way as the one already described, by the
intertwining of lateral branches. The mature bulbil, however,
tends to be more spherical than that in which a lateral branch
_twines about the primary filament. Occasionally several bulbils
_ may be produced from the same filaments, as is indicated in fig. 24,
which shows the bees of 3 bulbils at a, b, and c respectively.
_ Ata the seconde : are beginning to be formed in a manner _
siitilar 40: that shoe ta he. 20. It is possible that a and 6 will
merge into one, forming an elongated and more or less irregular
bulbil (text fig. 1). Owing to the variation in the mode of develop-
ment, a great diversity of form is produced. Text fig. 1 i BE |
_ a group of bulbils showing this wide variation of form. The exact
_ dimensions of these bulbils vary from 112.5 to 338 m, but occasion:
ally even a greater difference than this is observed.
2 fe test the germinating power of these fruiting bodies, hanging
a iS = were made i in Van a cells. It was found ne in me 2
cron wares tne pee
1917] HOTSON—BULBIFEROUS FUNGI 273
Papulospora aurantiaca, n.sp. (figs. 25-38; text figs. 3, 4).—
Mycelium white at first, becoming yellowish with age, procumbent,
scanty on most media, densely filled with oil globules, clamp con-
nections sparingly produced; bulbils pale yellow, becoming orange,
nearly spherical, frequently aggregated, 100-250 in diameter;
primordium a spiral of one or two turns. No other mode of repro-
duction at present known.
On bark collected by Dr. THAXTER near Port of Spain, Trinidad, W-I.
Fics. 3, 4.—P. aurantiaca: fig. 3, mature bulbil; fig. 4, several germinating
bulbils.
The mycelium of Papulospora aurantiaca is somewhat incon-
spicuous, the hyphae being small, usually about 2-5-3 .5 u in diam-
eter, and scanty. On certain media, like cornmeal or bran agar, it
omes more marked but never profuse on any media tried.
These included such nutrient material as potato, sugar, bran,
cornmeal, prune juice, horse dung, various kind of wood, etc.
The hyphae contain large numbers of oil globules which vary
considerably in size. When the filaments are crushed these float
out into the water, a number frequently fusing together and some- _
_ times forming large spherical globules 17.5 # or more in diameter.
Many and varied experiments have been made in the hope of -
causing the fungus to produce its perfect form, but thus far all oo
__ efforts have failed. That it is a Basid dily seen by
Ae presence of os connections in the myelin. a :
274 BOTANICAL GAZETTE [OCTOBER
small, more or less inconspicuous, and sparingly developed. There
are a number of basidiomycetous forms that produce bulbils as an
imperfect condition. In a former contribution (6) the writer has
referred to 4 such species, and in the present article 2 additional
ones are described. The reddish orange color of the bulbil under
consideration readily distinguished it from other species having
clamp connections. The bulbils of P. nigra and P. anomala are
dark brown or black, those of Corticium alutaceum chocolate brown,
and those of Grandinia crustosa straw colored with conspicuous
clamps.
Samples of the fruiting bodies of Sporodesmium aurantiacum —
B. and C., collected by Dr. THAXTER at Cranberry, North Carolina,
in August 1889, were obtained from him for comparison with the
bulbils of P. aurantiaca. As these structures were too old to
germinate, a comparison of their mode of development could not
be'made. The fruiting bodies of the two fungi resemble each other
so closely in their general form, color, texture, etc., however, that
there is little doubt but that they are identical.
DEVELOPMENT OF BULBIL.—In common with many other bul-
bils, those of P. aurantiaca begin by a short lateral branch coiling
- up spirally. The early stages in the development, with some of the
variations, are illustrated in figs. 25-38. During the process of -
coiling, which seldom results in more than two turns, the individual
cells comprising the primordium become well supplied with food
material and often appear distended (figs. 26, 27, 29). From the
cells composing the coil short branches are developed (figs. 27, 28,
ay, 0); Thee secondary branches may twine about each other
or they may enlarge, forming cells that resemble those ahteneirn oe
_ by a process of gemmation in other bulbils. These short b a
: and cells continue to be formed, sometimes on the concave side of ae
rve e: on wae convex side, until i all trace bee
| and |
1917] HOTSON—BULBIFEROUS FUNGI 275
the fruiting bodies of Sporodesmium aurantiacum B. and C., already
mentioned. In their early development the bulbils are usually
very irregular in outline, owing to the projection of secondary
branches which become less prominent in the mature form.
Frequently the bulbils appear as orange or yellowish patches
scattered over the surface of the culture instead of being distributed
evenly. This is due to the fact that the primordia are often pro-
duced in large numbers on a single branch, as shown in figs. 35, 36.
As these develop, a corresponding number of bulbils are produced,
which adhere together for a considerable time, superficially
Fics. 5, 6.—P. nigra: fig. 5, group of ee bulbils; fig. 6, , group of mature
bulbils, showing general form and variations in size.
resembling sclerotia. As a rule, these bulbils develop very dooty, ;
usually taking several months before they mature. Eventually,
however, as the substratum becomes dried up, the individuals
Separate into powdery, orange colored masses. The bulbils
germinate readily in nutrient fluid, several - which are shown i Se
text fig. 4.
Papulospora nigra, n.sp. Poe 40-47; Noe ey 5 6) Mycelium Ee :
white, procumbent, scanty, oil globules and clamp connections
_ Conspicuous; bulbils colorless at first, becoming dark brow:
black, nearly spherical, roo-180 in dane at maturity; pri-
: sims one or more short lateral, peace: which coil up
276 BOTANICAL GAZETTE [OCTOBER
On old cardboard, Cambridge, Massachusetts, and on hardwood chips,
Seattle, Washington.
Papulospora nigra was obtained from gross cultures of old
- cardboard in the cryptogamic laboratories of Harvard University,
and on similar cultures of chips in the botanical laboratory of the
University of Washington, Seattle. When the bulbils appeared,
pure cultures were made in a manner similar to that already
described. This species has been grown on a variety of media for
8 years without the perfect condition being obtained. The myce-
lium is white and remains so throughout the period of rapid growth.
Only when the hyphae get old do they begin to change color, becom-
ing brownish or smoke colored. The primary mycelium is pro-
cumbent and on most media is inconspicuous, but becomes more
or less flocculent or cobwebby on bran or prune agar. When 4
culture becomes old, the whole surface is covered with black bulbils
which completely obliterate the mycelium. The hyphae frequently
contain many large, conspicuous oil globules (figs. 40-42). The
mycelium also has quite prominent clamp connections, a condi
indicating its relation to the Basidiomycetes.
The bulbils of this species resemble closely those of P. anomala
Hotson (6) in size, form, and color. They are readily distinguished,
however, by their mode of development. In the latter species the
_ bulbils arise from ‘‘slightly swollen, colorless, intercalary cls
. . - . about 4 or 5 w in diameter, sometimes projecting consider-
ably and resembling short stunted branches; at other times
_ base of a short lateral hypha swells slightly and forms the primor-
dium.” From these primordial cells branches are sent out in
different directions, the lateral walls of the basal cells adhering —
firmly together and becoming eventually incorporated into the
bulbils. It will be seen that the development of the bulbil of =
: P. nigra is quite different from this. It has already been shown
may readily be distinguished from those of Corticium alutaceum, — .
2 thos of Grandinia ersten by t a oe
ation of P. aurantiaca that the bulbils of P. mgr
1917] HOTSON—BULBIFEROUS FUNGI 277
are developed which intertwine, sometimes incorporating the
primary filament. If the lateral branch divides, as it not infre-
quently does, the two filaments thus formed coil up, and these
with those that are subsequently produced from them intertwine
(figs. 44, 45). During the early stages of development the cell
walls are usually clearly distinguished, but as the bulbil grows
they become more or less transparent and quite indistinct (figs. 45,
46). At the stage represented in fig. 46 the whole bulbil is color-
less, the cells containing a large number of oil globules, which con-
dition continues until almost maturity, when they begin to turn
brownish. The walls gradually become more pronounced, and on
account of lateral pressure they assume a more definitely angular
condition. As the bulbils increase in size they become more and
more spherical, so that at maturity they have a clear cut, even
margin. Text fig. 6 represents a group of these bulbils. Although
they vary considerably in size, the general spherical form and even
outline is maintained throughout. Sometimes elongated, irregular
bulbils are formed when two primordia happen to be close together
and fuse as they develop. These, however, are the exceptions, and
the cause of their abnormal condition can usually be detccted.
If the bulbils are produced rather sparingly or away from each
other, they invariably become spherical.
These b iti ‘dia Vans Ticgliens
cell or in a watch glass. Fig. Sheed ie eee we =
ae, Oe ee ataeter, after 48 hours in a hanging drop. Text
fter 3days. It may be noticed
Mike as sok we i coe 6. = i:
20 eo iPaeleny as the hyphae are produced, the eve
eee ineved aside and disarranged, pent when ne
278 BOTANICAL GAZETTE [OCTOBER
In June 1915 the writer obtained a pure culture of Papulospora
magnifica from Dr. B. O. Dopce for identification, with permission
to make a cultural study of it. The fungus was originally found
in New York City in April 1912, associated with Ascobolus mag-
nificus Dodge, growing on horse dung in moist chamber cultures.
Donce (3) is inclined to consider this as parasitic on the mycelium
of A. magnificus, having traced ‘‘a direct connection between the
mycelium of the parasite . . . . and the mycelium of the host.”
He also shows by figures this definite connection. In a later
statement (4) he suggests that the Papulospora may be anes,
with Ascobolus magnificus “either as a parasite or as an
spore form of the Ascobolus. If the former is the case, the ee
of the parasite is intrahyphal; if the latter is true, then the phe-
nomenon known as ‘Durchwachsung’ is extremely complicated
in the mycelium of this Ascobolus.”’
As has already been indicated, bulbils must in all instances be
regarded as representing imperfect conditions of the higher fungi;
and, like the members of other more or less clearly defined form
genera, may be associated with perfect conditions included in
wholly unrelated genera of the Ascomycetes and Basidiomycetes.
A bulbiferous condition has been found associated with the genus
Cubonia (6) belonging to the same family as Ascobolus, so that it is
not inconsistent with the general characteristics of the form genus
_ Papulospora to consider the bulbils of P. magnifica as an imperfect —
condition of Ascobolus magnificus. All efforts, however, have
failed to obtain the ascocarp from pure cultures of the a
although repeated attempts have been made to do so by growing :
the fungus on a great variety of media which were exposed to differ-
_ ent constant temperatures. Although the majority of the species: oe
of sib ehiesters are. > undoubtedly saprophytic, there are some
stb by Riecae (7) as parasitic on beets, while Cosranrty (2) se
- described P °. dalliae as connected with the roots of dahlias, pens
P. parasitica (Karsten) BH was de
eventually develops i
1917] HOTSON—BULBIFEROUS FUNGI 279
definitely traced for some distance inside the filaments of Ascobolus
magnificus, we are led to the conclusion that the fungus under
consideration is parasitic on the latter rather than that the bulbil
is the imperfect condition of it. On all the cultures made of
P. magnifica the mycelium grew very sparingly, being procumbent,
and at times growing down into the medium, but never becoming
flocculent or aerial. On potato, bran, prune, and cornmeal agar
only a small amount of mycelium was produced even after several
months. So meager was the development that it might easily
have been overlooked unless examined carefully with a hand lens.
Of the different media tried, a decoction of horse dung with agar
or the horse dung itself, sterilized in an Arnold’s steam sterilizer,
proved the most satisfactory.
A microscopic examination frequently showed the mycelium
to be a network of anastomosing hyphae (fig. 69), while at other
times (figs. 65-68) enlarged food storage cells were found, the
largest being 15 » in diameter.
DEVELOPMENT OF BULBIL.—The primordium of the bulbil is
quite easily recognized as a short lateral branch, somewhat coiled _
or curved and well filled with copmurond ee vi cae develop- .
ment the bulbil seldom, if ever, p , such
as does P. parasitica, which it acet closely resembles. From the
_ end of this coiled branch a cell is cut off, enlarges, a becomes
well filled with granular food material (figs. 54, 55). This cl
a PO ee | bil. © ;
nt tha
= Aas
eda tis iced beac oes oo all epresel .
Wes: St: <5. wile ut other Gel « secondary Wrctic & renee
from it (figs. 50, 52). The usual mode of procedure, however, is ee
that Shown i in see te 49» 54, 55- At may be seen that the end © oo
280 BOTANICAL GAZETTE [ocTOBER
laterally. In the course of development these outer cells lose their
protoplasmic contents, although the walls retain more or less of
the brownish color.
Although the foregoing description of the mode of develovae!
of the bulbil is the usual one, not infrequently a second large cell
is formed by the primordial branch (figs. 62,63). In such instances
the further development is practically the same as where there is
a single central cell. The lateral branches which eventually become
the cortex are produced from both the large cells, which subsequently
become completely surrounded, precisely as in the case already
described. |
Germination of bulbil
The bulbils of most of the species of Papulospora germinate
with little difficulty. All of those described in this article, with
the exception of P. magnifica, have been found to produce rs
tubes quite readily. In the study of that species various
were employed in the hope that a favorable condition might be
ound for the germination of the bulbils. Among these were
bran, potato, and prune agar, various synthetic media, as well
as decoctions of horse dung used both as a liquid and associated
with agar, but all these failed to produce the desired result.
Finally a method that the writer had found successful in in-
ducing the ascospores of certain species of Ascobolus and Cubonia —
(6) to germinate was tried with some success. Mature bulbils
were put on a flamed glass slide and carefully crushed with the
‘flat surface of a scalpel. They were then transferred to hanging
drops of nutrient media, a sterile decoction of horse dung proving :
the best. Many of the bulbils thus crushed were totally destroyed,
_ but in a few instances, where the pressure was just sufficient to
_ break the cortical layer of cells without injuring the large central i
one, germination was ‘produced and a branching filament soon
developed (fig. 39). ce
7 "The mature ball of P- magnifica, with one or two large ceminal
? os surrounded by empty cortical ones, superficially resembles -
co sate ste of 2. enone ay, Hotson. The latter, el :
1917] HOTSON—BULBIFEROUS FUNGI 281
spiral primordium of P. coprophila and the flocculent and abundant
mycelium differ widely from those of P. magnifica. The bulbils
of P. magnifica more closely resemble those of P. parasitica (Kar-
sten) Hotson than they do those of P. coprophila. However, in
P. parasitica, which is described as parasitic on beets in the original
description by Karsten, the mycelium is flocculent, the bulbils
15-21 w in diameter, with a single large central cell invariably
present, and the primordium a spiral which coils crosier fashion.
Thus, the procumbent and scanty character of the mycelium of
P. magnifica, as well as the size and mode of development of the
bulbil, readily distinguish it from P. parasitica. In order to obtain
further information regarding the relationship of these two fungi,
inoculations were made in the roots of growing beets and turnips,
both in the field and in the laboratory. In each case a small slice
of the root was removed with a sterile knife and a cavity made in
the cut surface. From a pure culture of P. magnifica a portion
of the nutrient agar containing bulbils and mycelium was gouged
out and deposited in this cavity. Over this a small piece of —
glass was put and the soil replaced. Although several similar
experiments were carried on, no indication of a parasitic condition
could be detected.
Other species that resemble the two just mentioned, such as
_ Physomyces heterosporus (Monascus heterosporus [Harx] Schréter), oo
Dendryphium bulbilferum Zukal, Acrospeira mirabilis Berk. and
Br., etc., have al discussed (6), so that it is not necessary
to repeat the discussion. ,
Key to species of bulbiferous fungi
__ There are several more or less well defined characteristics that
_are made use of in making the following key for the members of t
. a form genus Papulospora. A broad division sexily made on the ae
282 BOTANICAL GAZETTE [OCTOBER
cells, a single lateral branch, or a group of vertical hyphae. Using
these characters as a fundamental basis for separation, the described
species of bulbiferous fungi may be distinguished as follows:
Hyphae with clamp connections
Bulbils dark brown to black
Bulbils 65-80 yw in diameter, chocolate brown. ...... Corticium alutaceum
— 125-175 » in diameter, dark brown or black; margin even
Premorinim toteriaey ek eke ee Papulospora anomala
Piemonte ie. Papulospora nigra
Bulbils light yellow, 52-88 w in diameter; hyphae ae ropelike
andinia crustosa
gpa yellow, becoming orange, 100-250 » in diameter; hyphae formed
UI oo a Papulospora aurantiaca
tikes without clamp connections
Bulbils colorless, pale yellow, or cream colored
Bulbils cream colored, 30-35 » in diameter; parasitic on Geoglossum
Papulospora candida
Bulbils colorless or pale yellow, 79-100 pt in diameter, saprophytic
Papulospora pallidula
Bulbils steel gray, 21-36 » in diameter............... Papulospora cinerea
—Bulbils black or smoke color ce
Bulbils 75-100 » in diameter; margin even..........- Cubonia bulbifera
Bulbils 200-300 p in diameter; margin a ..Papulospora pannosd
Bulbils yellowish red to dark brown a
‘Bulbils scanty; perithecia u inate present —
hecee = with neck and lateral and terminal setae
Melanospora cervicula
_ Perithecia with papilla and terminal setae... .. . Melanospora papillate
Bulbils abundant; perithecia — t
Primordium intercalary
ee ee cites] cells sag rence
Papulospora immerso
Bulbils straw color; central ols 10-20 pw in diameter
Reser ‘ripe
-Primordium one or more lateral branches
oC
oe
"Cells of the bulb beteroencos; cortex definite ce tee
_ Normally only -
~ Cortex complete - - ae ne
S —— pocumbent bulbil a sr-s0n in
T917] HOTSON—BULBIFEROUS FUNGI 283
Mycelium abundant, flocculent; bulbil rs5—21 be in
diameter; iigieie: 1-celled. . . Papulospora par
Cortex moomilete. . 2-5. 4, co Acrospeira mirabilis
Normally more than one central cell
Spiral in one plane; cortical cells spinulose
Papulospora spinulosa
Spiral normally in more than one plane; not spinulose;
2-6 central cells
Bulbils dark brown... 2. ........., hase coprophila
Bulbile brick ved... 5 ok, Papulospora rubida
Cells of bulbil homogeneous throughout
Bulbils chocolate brown, 21-36m in diameter, producing
Sporotrichum spores........... Papulospora sporotrichoides
‘Bulbils straw color, 100-2 oe ree Papulospora byssina
Primordium not spiral; bulbils large, fecaulan 100-750 p in diam-
Os a Papulospora aspergilliformis
Primordium two or more lateral branches forming a spherical aggre-
gation of cells at the top... .............. _- Papulospora polyspora
UNIVERSITY oF WASHINGTON
SEATTLE, WASH.
1. Bainter, G., Evolution du Papulospora aspergilliformis et étude de deux
Ascodesmis no uveaux. Bull. Soc. Mycol. France 23:132. 1907.
2. CosTANTIN, J., Note sur une Papulospora. Jour. Botanique 2:91. 1888.
3- Donce, B. O., Artificial cultures of Ascobolus and Aleuria. “Mycologia
4:218-221. ois. 2. 1912:
, The Pi Papulospora question —— to Ascobolus. Science NS.
: 4t:173. 1915.
5- Fawcert, H. S., An important entomogenous fungus. "Mycologia 25164.
IQIo.
gc ter ul , Culture studies of fing) producing ‘bulbils and similar
Proc. Amer. mene ian to bedi r2. 1912.
oe
+. Kies, 9 esache | einer Moh:
_ Lab. Landwirt. Berlin 1: 76-83. 1865.
8. bese amg ROSENBAUM, ne Sponospora
-. homa tuberosa on n the Irish potato. Jour. Agric. R
ior :
9. Neces, F. Wo Uber Ureduciy Abalebs
_ reaceen. lean Centralbl. ec oe 1914.
284 BOTANICAL GAZETTE [OCTOBER
in the development of bulbils were drawn with the same magnification, using
4 mm. objective and no. 12 eyepiece. The text figures are microphotographs
taken by W. J. WESTERBERG. The plates have all been reduced in repro-
duction about three-fourths.
Fics. 1-16.—Papulospora pallidula.
Fic. 1.—Hypha showing large oil globules.
Fics. 2-6.—Dichotomously dividing primordium
Fics. 7, 8.—Primordia more or less irregular in hess dichotomous branch-
Fic. 9.—Further development of bulbil.
Fics. ro-12.—-Second mode of forming a bulbil.
Fic. 13.—Mature bulbil germinating.
Fic. 14.—Cells of an old t bulbil loosely adhering to each other; some of
cells germinating.
Fics. 15, 16.—Terminal primordia.
Fics. 17-24.—Papulospora byssina.
ing
Fic. 24.—Primordia of at least 3 bulbils ad same filament at a, b, and ¢
ern s
25-38.—Papulospora aurantiaca. :
Pros. 25-32- —Variations in mode of coiling of primordium of bulbil.
Fics. 33-38. of bulbil. :
Fic. 39.—Germinating bulbil of Populespora magnificus.
_ Fics. 40-47.—Papulospora nigr :
Fie. 40-—Portion of hypha showing large il globules and clamp comme i
ee ny Sige, inthe macy Serenata ee Np :
he ichsec oo of oe with haces pie cells ——* fled
PLATE XX]
BOTANICAL GAZETTE, LXIV
HOTSON on BULBIFEROUS FUNGI _
BOTANICAL GAZETTE, LXIV PLATE XXII
BOTANICAL GAZETTE, LXIV PLATE XXIII
eee é
ss iiweSSs
i
fy.
Ry
| CRYOSCOPIC DETERMINATIONS ON TISSUE FLUIDS
OF PLANTS OF JAMAICAN COASTAL DESERTS!
J. ARTHUR HARRIS AND JOHN V. LAWRENCE
Introduction
PURPOSE OF STUDY.—In a memoir recently published? we have
discussed in detail the reasons for considering the physico-chemical
properties of vegetable saps a subject of real importance in ecology .
and phytogeography, and have reinforced the arguments advanced
by series of determinations showing distinct differences in the
osmotic pressure, or osmotic concentration, as some prefer to call it,
of leaf sap from plants growing in different local habitats in the
Arizona deserts. A comparison of these determinations with a
series made in the more mesophytic region of the Station for
Experimental Evolution? demonstrated a conspicuous differentia-
tion of the Tucson and Cold Spring Harbor regions with respect to
the osmotic concentration of the tissue fluids of the constituent
species. In view of the s diff tablished between
these two floras, it seemed desivable to select a forested region of as
uniformly distributed and as nearly maximum rainfall as possible —
for comparison with the areas already studied. Thus we hoped to
3 the iohtaha tals force ol the asad of Tenis wey de |
by Sureve,* seemed the most suitable locality. ‘We therefore
spent a period of several uring t eae ree
286 BOTANICAL GAZETTE [OCTOBER
of 1915 in a study of the osmotic concentration of the tissue fluids
of the plants of the montane region. The results of this study will
be published later. Fortunately, while in Jamaica we were
also able to visit the remarkable coastal deserts of the southern
shore. It seemed to us highly desirable to secure as large a series
of determinations as possible upon the species constituting their
flora for comparison with the observations already made in the
Arizona deserts in the neighborhood of the Desert Laboratory.
Our purpose in this paper, therefore, is to present a considerable
series of novel physiological data on the plants of the desert area of
the southern coast of Jamaica; to compare the flora in this regard
with that of the southern Arizona deserts and of some other locali-
ties; and to hazard some — concerning biological factors —
immediately underlying certain of the differences observed in
various species of the coastal region.
_ CHARACTERISTICS OF DESERTS INVESTIGATED.—Lying as it does —
in the center of the Carribean Sea, the island of Jamaica intercepts
the trade winds in a way to cause a pronounced differentiation in
its climatic conditions. This is especially true on the narrow 2 S
eastern end, where the Blue Mountains, attaining a height of nearly =
7500 feet, separate two narrow coast plains. At Port Antonio, at
_ Sea level on the northern coast of the island, the mean annual
ae -.con, at sea level oe
= ‘ on the southern coast of the island, precipitation is on the average - : |
ae less. than 38 inches per year. Temperature and insolation char
acteristic of sea level at 18° N. latitude coupled with local peculiari-
ties of the substratum have here resulted in & conspicuously ne
rainfall averages more than 130 inches. At
: _—_-xerophytic type of vegetation.
sy the island from the mouth of the Cane River, just east of | oe
for a distance of about 7o miles to the Pedro Bluffs. Its greatest oe
_ As limited by SHREVES, the desert deers the southern oo of : Z
SF ac is = in the Healthshire Hills, in the vi icir mad of ee
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 287
Pen. The desert is confined to the limestone areas which have an
extremely rough surface, with layers or shallow pockets of soil
which are not capable of retaining moisture or of deriving it by
capillarity, and to the finely ground substratum of the coastal
flats. The proximity of the sea and other factors maintain a high
relative humidity. Atmometer readings by SHREVE indicate that .
the evaporation rates here and at Hope Gardens, which is some 6
miles inland and behind a low ridge of hills, are not very different.
All of our collections were made in the immediate vicinity of Port
Henderson, a point easily accessible from Spanish Town, where it
was possible to carry out the laboratory phases of the work, and
which afforded access to both the rocky limestone hills and the
coastal flats. Because of military restrictions, made with great
courtesy, we were unable to visit all parts of the region. Probably
distribution of the collections over a wider area would have modified
but little the cache here drawn, anne it _—— have in-
creased the number of species upon which de are based.
The area considered comprises open beach, a mangrove swamp,
a highly saline tract of mud flats practically free of vegetation,
somewhat higher-lying flats of finely ground detrital material, and
rocky limestone hills, the soil = which i is relatively ane om
retaining water. =
The determinations hick we we made on the plants of the om
each and on those of the a grove swamp resel ae for a lis u : . : :
pep eEse ties of strand and mangrove swamp species, =
to be published laer " data a. other habitats (many of - rhich
have already been collected) are ready. The vegetation of ie ee
, rpalaigcd — aud flats is practically limited to the two well aS
, of = .
eet ie former i is much the more ‘common, and the two ‘man- Se :
: Avicennia nitida and —e racemosa, which occur
288 BOTANICAL GAZETTE [OCTOBER
species, or upon cacti. Here, as is generally the case in desert
regions, the classification of the plants with respect to growth
form presents considerable difficulty. Trees are shrublike in stat-
ure and shrubs are correspondingly reduced in size. In spots where
the soil is deeper or more retentive of moisture the size of the
individuals may be much greater.
Describing the vegetation in terms of the species upon which we
were able to secure determinations, we may note that the vegeta-
tion of the coastal flats is made up chiefly of a mesquite tree Prosopis
juliflora, and a columnar cactus Lemairocereus Hystrix. Other trees
or shrubs are Caesalpinia vesicaria, Capparis cynophallophora,
C. ferruginea, and Guaiacum officinale. Our lists show determina-
tions for 7 species of cacti. In addition to these, Sesuvium Portu-
lacastrum, Batis maritima, and in places Bromelia Pinguin are
abundant. On the rocky hillsides the more truly arborescent forms
are Bauhinia divaricata, Caesalpinia vesicaria, Canella Winterana,
Capparis ferruginea, Cassia emarginata, Ichthyomethia Piscipula,
Melicocca bijuga, Prosopis juliflora, Sarcomphalus Sarcomphalus,
Schoepfia chrysophylloides, and Tamarindus indica. The shrubs are
Chiococca alba, Croton flavens, Hypelate trifoliata, Lantana crocea (?),
Morinda Roioc, Solanum bahamense, and Turnera ulmifolia. The
smaller ligneous species are the dwarf shrubs or half shrubs
Achyranthes halimifolia, Lantana reticulata, and Jatropha gossyp-
folia, and the twiners Echites Echites and Phillivertella clausa. The
only monocotyledonous plant from which a determination was
secured was Bromelia Pinguin. The only herbaceous succulent
noted was Bryophylium pinnatum.
The cacti may also occur on the rocky hills, but in the immediate
vicinity of Port Henderson the flora is almost exclusively of small
trees and shrubs.
There are but few species in our series of determinations éeencains
to the two habitats. These are Achyranthes halimifolia, C aesalpinia
vesicaria, Capparis ferruginea, Jatropha gossypifolia, a and Prosopts
julifiora.
MeEtHops.—The very simple technique used in making the
determinations has been described in detail elsewhere. Samples
® Gortner, R. A., and Harris, J. ARTHUR, Notes on the technique of cout
the depression of the tenting point. Plant World 17:49-53. 1914-
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 289
of tissue were collected in test tubes of about 100 cc. capacity and
taken to the laboratory for freezing by immersion for several hours
in an ice and salt mixture, in order to avoid errors in the extraction
of sap as noted by Drxon and Arxins’ and ourselves.’ The sap
was then extracted by pressure in a small heavily tinned press bowl
with a powerful hand screw. After filtering, the freezing-point
lowering of the sap was determined by the use of a thermometer
graduated in hundredths of degrees with divisions sufficiently large
to permit reading approximately to thousandths of degrees.
In some instances a cloudiness or flocculent precipitate similar
to that described by GorKE? was observed when the sap approached
the freezing point or passed it in undercooling. We had no facilities
for any investigation of these substances, but believe their pressure
does not greatly, if at all, influence our results.
The measurements are recorded in degrees depression (A)
corrected for undercooling and in atmospheres pressure (P) from a
table published elsewhere.” The fact that a number of the deter-
minations exceeded the range of the table as originally printed has
led to the publication of a supplementary one."
Presentation and analysis of data
In the following protocol the values to the extreme right opposite
the species names are (whenever possible) averages. These averages
are designated by bars. The individual readings upon which they
are based, with their dates of collection,are entered below the species,
except in the cases in which only a single determination is available
and must serve, instead of an average, to represent the species.
7 Drxon, H. H., and Arxins, W. R. G., Osmotic pressures in plants. I. Methods
of extracting sap from ont ores Sci. Proc. Roy. Dublin Soc. N.S. 13:422-433.
1913; alsoi h. Trin. Coll. Dublin 2:154-172. 1913-
§ Gortner, R. A. piiceen i V., and Harris, J. ArtHUR, The extraction
of sap from ae tissues by pressure. B iochem . Bull. 5:139-142. pl. I. 1916.
° Gorxe, H., Uber chemische Voeskhee beim Erfrieren der Pflanzen. Land-
seas Wecual Stat. 65:149-160. 1906.
* Harris, J. ARTHUR, and GorTNER, R. A., Note on the apc of oa —
reprinted in Matrnew’s Physiological Chemistry.
™ Harris, J. ARTHUR, An extension to 5. 6s ot tables to determine the osmotic
Pressure of exp: of the freezing point. Amer.
Jour. Bot. 2: 2418-419. 191s.
290 BOTANICAL GAZETTE [OCTOBER
A. THE COASTAL FLATS
The following determinations were made on the sap extracted
from the leaves of the small more or less sclerophyllous trees.
en WOUICI I Bi ee ia in coche cos ina ees A=2.95, P=35.4
January 25, A=2.91, P=34.9
March 26, A=3.08, co. °
March 30, A=2. 87, P =3
Capparis cynophallophora L. c pid OPED, tect A=3.76, P=45.0
January 30, A=3.87, P=46.4
COPOOrts TUTRNINEE Bie Se a i es A=4.12, P=49.3
January 25, A=4.10, P=49.1
March 30, A=4.13, P=49.4 se fee
CAG HIE a ee cd ices ta teins A=4.35, P=52.1
January 25, A=4.48, P=53.6
March 26, A=4.22, P=50.5
30, A=2.42, P=29.1
April 2, A=2.63, P=31.5
Three species which may be classified as dwarf shrubs or half
shrubs gave
Achyranthes halimifolta Lam. : 2.0... oe ee ee i ee i ok A=2.86, P=34.3
anuary 22, A=3.23, P=38.7
January 25, A=2.48, P=29.8 — =
SOeree WI Te ek ei ek A=4.18, P=50.0
January 22, A=4.18, P=50.0
January 25, A=3.84, P=46.0
March 26, A=4.58, P=54.8
March 30, A=4.12, P=49.3 a8 ae
OM ODIE MULIIOITONG Doi es a a =1.17,P=14.1
January 25, A=1.24, P=14.9
January 30, A=1.10, P=13.2
Our visit was not made during the time of the development of
ephemeral plants. The only herbaceous form which we secured
was the well known halophyte Sesuvium..
| A=2.86, P=34-3
he ee ee ee
March 30, A=2.11, P=25.4
April 2; A=1.63, '=19.5
1917]
HARRIS & LAWRENCE—TISSUE FLUIDS
291
A portion of the foregoing species are sclerophyllous and a
portion are succulent-leaved plants.
The tissues of the Cactaceae,
which are the dominant forms on the coastal flats, yield fluids
giving the following values:
Cactus Melocactus L.
anuary 22, for cortex, A=o.40, P=4.9
for pith, A=o0.49, P=5.9
March 30, A=o0.46, P=5.5
April
2,
Cephalocereus Swartzii (Griseb.) Britton and Rese
March 30, for cortex, A=o.59, P=7.1
for pith, A=o.70, P=8.5
April 2, - cortex, A=o.59, P=7.1
ith, A=o0.69, P=8.3
an gracilis (Mill. Britton
March 26, for cortex, A=o.53, P=6.
Hylocereus triangularis (Mill.) Britton and Rose
January 25, A=o0.48, P=
Lemairocereus Hystrix (Solm Byck) Britton and Rose
f
or cortex, A=o0.64, P=
for pith, A=0.75, P=9.0
January 25, for cortex, A=o.44, P=5.2
for pith, A=0.64, P=7.7
A=0.64, P=7.6
March 30, for cortex, A=o.53, P=6.3
for pith, A=o0.57, P=6.9
April 2, for cortex, A=o.80, P=9.7
for pith, A=o0.76, P=9.1
March 26,
Opuntia Dillenii (Ker Gawl.) Haw.
January 25, A=o.57, P=6.8
March 30, A=o.75, P=9.0
April 2, A=o.69, P=8.3
Opuntia spinosissima Mill.
6.8
March 26, A=o.78, P= 9.4
8.6
I
April 2, A=o.93, P=11.
The only monocotyledonous plant studied was the terrestrial
Bromelia, which may be included here
Bromelia Pinguin L
eee eee ee eee www ee eee ee
March 26, A=0.63, P=7.6
292 BOTANICAL GAZETTE [OCTOBER
B. THE ROCKY HILLS
The classification of the plants from the rocky hills into trees,
shrubs, and other growth forms has been indicated in the foregoing
introductory section. Here, therefore, we merely give the results of
the determinations in alphabetical order.
, — oe BR he ce ess. da eek A=2.83, P=33-9
Mar 26, A=3.16, P=37.9
March 30, A=2.49, P=29.9
Bauhinia divaricata L
January 27, A=3.10, P=37.2
January 30, A=2.98, P=35.8 as oe
ees PU a a ee Se A=0.58, P= 7.0
anh
7
joes pinnatum (Lam.) Kurz. oda cecssuw es eOg4, FO 5-5
March 26, A=o.49, P= 5.9
March 30, A=o0.37, P= 4.5
April 2, A=o.50, P= 6.0
Caesalpinia vesicaria L...........0.5..0-.-. January 27, A=2.26, P=27.2
] A
Capparis tavrepiahe oe ee ie Se A=3.58, P=42.9
January 30, A=3.50, P=41.9
March 26, A=3.66, P=43.8 mn
Cassia emarpdie Ti ee oe ss A=1.97, P=23-6
January 27, A=1.99, P=23.9
anuary 30, A=1.94, P=23.3
Chiococca alba i pee a, January 25, A=3.64, P=43.6
Croton flavens L..... 2.2.2.2 eV a January 27, A=1.47, P=17-7
Echites Echites as Britton (Echites umbellata Jacq.)
January 27, A=1.78, P=21-4
Hyfelale WE MIMG SW oo a aa ce A=2.34, P=28.1
Jan
uary 30, A=2.30, P=27.6
Ichthyomethia Piscipula (L.) Hitch........... March 30, A=1.49, P=18.0
Jalrobha gossybiielia Lien cs January 30, A=1.02, P=12-3
ieee Tee ee rch 26, A=1.60, P=19-2
Lantana reticulata Pers... .....: 2... 03... January 27, A=2.14, P=25-7
Moldcwca RGN Lia es: A=1.87, P=22.4
anuary 30, A=1.73, P=20.8
March 30, A=1.73, P=20.8
April 2, A=2.14, P=25.7
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 293
MIE Tlie Tigo tis rok ge an A=1.76, P=21.2
March 26, A=1.77, P=21.3
March 26, A=1.76, P=21.1
aT se ae 1.84, P=22.1
i 1.68, P=20.2
Philibertella oa: (Jaca, Ves ANE ee oe January 27, A=1.51, P=18.2
Evosopss juliflora (L.) D.C... . 5 osc, January 27, A=2.69, P=32.3
Sarcomphalus S vince (L.) (Sarcomphalus laurinus Griseb.)
January 27, A=1.63, P=19.6
Schoepfia chrysophylloides (Rich.) Planch................. A=2.79, P=33.5
uary 27, A= , P=30.2
January 30, A=2.66, P=32.0
March 26, A=2.93, P=35.1
il 2, A=3.06, P=36.7
pein bokamonse Lo a, A=1.98, P=23.8
, A=2.09, P=25. We ‘
Tidbits oe Bi ee at re ee es A=1.75, P=21.0
Apri 2,
“Whee Geena th. 2 January 25, A=3.39, P=40.7
Analysis of data
In the analysis of these data the first step is to put on one side
the two species with more or less succulent leaves, Bromelia Pinguin
and Bryophyllum pinnatum, and the cacti. These show low con-
centrations of about 6-9 atmospheres. They are not at all com-
parable with the other forms investigated in these deserts and
elsewhere and will be discussed separately on a subsequent
page.
Of the thin-leaved forms, Jatropha gossypifolia has a thickened,
almost succulent stem. It is a form much more characteristic of
the coastal flats than of the rocky hillsides. The rather tender
leaves yield a sap of lower concentration than that of any other thin-
leaved species.
204 BOTANICAL GAZETTE [OCTOBER
AVERAGE CONCENTRATION IN COASTAL DESERTS.—As a pre-
liminary to any further analysis of these data the average values
for the two habitats and the different growth forms must be
obtained.
For the 5 arborescent species of the coastal flats the general
average is given by
Caesalpinia A=2.95, P=35.4
Capparis A=3.76, P=45.0
Capparis A=4.12, P=49.3
Guaiacum A=4.35, P=52.1
Prosopis A=2.53, P=30.3
General average 3.542 42.42
The 3 species of the coastal flats which have been classified
as dwarf shrubs differ greatly in concentration. Achyranthes is a
rather hard-leaved halophyte which does not penetrate to the most
saline spots. It is characterized by a concentration of about 34
atmospheres as compared with about 50 atmospheres in the highly
succulent Batis maritima, the sole species found in the more saline
spots. Sesuvium Portulacastrum is characteristic of only the less
saline portions of the flats, and shows a far lower average concentra-
tion, although some of the individual values attain about the
average for Batis.
The actual averages are: mean depression, 2.737°; mean con-
centration, 32.80 atmospheres.
For the more truly arborescent species of the rocky slopes the
values are: -
Bauhinia A=3.04, P=36.5
Caesalpinia A=2.26,'P=27.2
Canella A=3 18, P=38.1
shen A=3.58, P=42.9
sia A=1.97, P=23.6
Sean A=1.49, P=18.0
Melicocca A=1.87, P=22.4
Prosopis A=2 69, P=32 3
Sarcomphalus A=1 63, P= 19 6
Schoepha A=2.79, P=33.5
Tamarindus A=1.75, P=21.0 |
General average 2.388 28.6
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 295
The general average for the shrubs, half shrubs, and woody
twiners of the rocky slopes is given by
Achyranthes A=2.83, P=33.9
Chiococca A=3.64, P=43.6
Croton A=1.47, P=17.7
Echites A=1.78, P=21.4
Hypelate A=2.34, P=28.1
Jatropha A=1.02, P=12.3
Lantana A=1.60, P=19.2
Lantana A=2.14, P=25.7
Morinda A=1.76, P=21.2
Philibertella A=1.51, P=18.2
Solanum A=1.098, P=23.8
Turnera A=3.39, P=40.7
2.192 25.48
General average
Thus the concentrations determined for the smaller forms are
practically as large as those for the more truly arborescent species.
Combining all the ligneous perennials of the rocky slopes (that is,
omitting from the whole series of determinations only Bromelia and
Bryophyllum), we have for the general average of the species means
or species constants: mean depression, 2.249°; mean concentra-
tion, 27.000 atmospheres.
Combining both arborescent and suffrutescent growth forms,
excepting only the herbaceous Sesuvium Portulacastrum, Bromelia,
Bryophyllum, and the cacti, the values for the 31 species means
or constants of the two habitats recognized give the following
averages: mean depression, 2.505°; mean concentration, 30.05
atmospheres. By including the herbaceous perennial Sesuvium,
the averages for 32 species means or determinations is changed
to A=2.516, P=30. 18.
COMPARISON OF CONSTANTS WITH THOSE FOR MESOPHYTIC
REGIONS.—The first question to be answered in the analysis of these
data is that concerning the relative values of osmotic concentration
in the sap of desert and mesophytic plant organisms. Specifically,
do the results of this study confirm those obtained by Frrrmnc” in
“ Firtinc, H., Die Wasserversorgung und die osmotischen Druckverhiltnisse
der Wiistenpflanzen. Zeitschr. Bot. 3:209-275- 1911.
296 BOTANICAL GAZETTE [ocroBER
his plasmolytic studies of the plants of North African deserts and
by ourselves in our cryoscopic determinations in the Arizona desert
region? With an affirmative answer to this question, a second one
concerning the closeness of agreement between the two desert
areas so far investigated is open to discussion.
Comparisons of the constants for sap properties here secured
with those for other regions must be drawn with care and in only a
preliminary fashion. This is quite obvious because of the many
factors which may influence the constants, but concerning which
little or no quantitative data are at present available. For example,
the determinations for the Arizona deserts are based on collections
made during the period of spring vegetative activity following the
winter and spring rains; those for the coastal deserts were made
during the dry winter season. The collections made on Long Island
and in St. Louis at the Missouri Botanical Garden comprise decidu-
ous species whose leaves must have developed during the spring
of the same year. The age of the leaves of the desert plants is often
quite indeterminable. Bearing these limitations in mind and
remembering that there are probably many others, we note first
of all that in a general way the flora of the Port Henderson deserts
is in excellent agreement with that of the Tucson region in showing
a high concentration of the tissue fluids of its constituent species.
The exceptions only emphasize the rule.
us comparing the Port Henderson averages for ligneous
perennials with those tentatively drawn from unpublished data
for trees and shrubs for the Cold Spring Harbor region," we fin
Cold Spring Harbor, 14.40 atmospheres
Jamaican coastal desert
Coastal flats only, 38.81 atmospheres
Rocky slopes only, 27.00 atmospheres
Flats and rocky slopes, 30.05 atmospheres.
B The averages given for both at _ ee Harbor and the Tucson series are
by GortNer, LAWRENCE, and Harris. They will he replaced shortly by
representing not merely determinations made in 1914 but far more extensive work ty
abe ee and Harris in rgrs and subsequent work by Harris. The field work has
ne for a summer series from the Arizona deserts, but the data cannot be com-
prorat worked up for some months.
‘
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 207
It is idle to go further into these comparisons. It is clear that
the ligneous plants of the Jamaican coastal desert, those of the
rocky hills as well as of the more or less saline flats, are character-
ized by concentration of tissue fluids about twice as great as those
of the Cold Spring Harbor region.
The extensive series of species studied by OHLWEILER™ suffer
from the disadvantage (in relation to the present paper) of being
assembled from their natural habitats and grown in a Botanical
Garden. All, however, are forms capable of growth in the open at
St. Louis. These show a range of from about 7 to about 24 atmos-
Pheres. The average value of the 90 determinations is 14.96
atmospheres. Thus, OHLWEILER’s St. Louis series agrees very
closely with our own preliminary average for Long Island habitats.
Here again the values are only about half as high as those deter-
mined in the coastal deserts.
COMPARISON OF CONSTANTS WITH THOSE FOR TUCSON REGION.—
Turning to averages for a comparison of the concentration of the
Sap of the Jamaican coastal and the Arizona desert floras, the
results for ligneous perennials only are: Arizona series, 24.97
atmospheres; Jamaican series, 30.05 atmospheres. Apparently
concentration is somewhat greater in the Jamaican series. If the
comparison between the two desert areas is to be drawn on a more
analytical basis, it may be noted that the values determined for the
trees of the coastal flats are of the same order of magnitude as those
derived from the species of Atriplex examined in the Arizona salt
Spots. For example:
Atriplex canescens P=39.5
Atriplex canescens P= 67.5
Atriplex canescens angustifolia P=32.8
Atriplex polycarpa P=52.0
In the Jamaican coastal deserts the trees and shrubs from the
rocky slopes show concentrations lower than those of the coastal
flats. In the Arizona deserts the plants of the rocky slopes show
far lower osmotic concentrations than do those of the salt spots.
_ Comparing Arizona and Jamaican rocky slopes the results are:
*4 OHLWEILER, W. W., The relation between the density of cell saps and the
Senne pemet ot of ‘ict: Ann. Rept. Mo. Bot. Gard. 23:101-131. pl. 6. 1912.
298 BOTANICAL GAZETTE [OCTOBER
Port Henderson region, 27.00 atmospheres; Tucson region, 22.01
atmospheres.
With the exception of the salt spots, the bajada slopes of the
Tucson region show the highest concentration. Comparing with
the rocky slopes of the coastal region, the results are: Port Hender-
son rocky slopes, 27.00 atmospheres; Tucson region, bajada,
30.34 atmospheres.
Because of seasonal differences it is undesirable to attempt to
analyze too closely the differences between the two desert areas.
Such could be done if determinations upon the coastal deserts
immediately subsequent to a rainy season were available. Until
such data.are at hand and until our determinations for the summer
flora of the Arizona deserts are ready for publication, it is premature
to discuss the matter further than to say that both of these regions
show concentrations far higher than do those of mesophytic habitats,
and that they are in good general agreement between themselves.
OsMOTIC CONCENTRATION IN THE CACcTI.—From the floristic
standpoint the most striking feature of these coastal deserts is the
remarkable growth of arborescent cacti in immediate proximity to
dense mangrove swamps. From the physiological standpoint the
most remarkable result of these studies is the demonstration that
the fluids of these cacti have about the same concentration as those
of other desert regions. .
The 28 determinations made on the sap of the 7 species
belonging to the 6 genera of cacti show a range of A=o.40 to
A=o.93, or P=4.9 to P=11.1, with an average for the series of
A=o.626 and P=7.52. Yet these cacti are growing in the same
substratum as sclerophyllous arborescent species with an average
concentration for the species of A=3.54 and P=42.4. Much of
the cactus-covered area has a dense undergrowth of Batis maritima,
which has an average of A=4.18, P=s0.0. Sesuvium, which
sometimes occurs but is not so abundant as Batis among the cacti,
has sap averaging A=2.60, P= =31.2. Better illustrations of the
diverse reaction of two organisms to the same general environ-
mental situation could hardly be found. These results are in close
agreement with the findings of those who have worked on
cacti in other regions.
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 299
As early as 1905 CAvARA’ investigated a series of cacti by the
freezing-point lowering method and gave values not very dissimilar
from our own. Sap was extracted from untreated tissue. This
may result in abnormally low values of the measures of osmotic
concentration.
MacDovueat and Cannon” have estimated the following con-
centrations in atmospheres for sap of cacti at 25°C: Carnegiea
gigantea, 6.78; Echinocactus Wislizenii, 5.72; Opuntia Blakeana,
8.88 and O. versicolor, 11.98.
It is interesting from the historical standpoint to note that cacti,
which with certain other succulents are quite anomalous among
desert plants, were perhaps the first to be considered in relation to
the problem of the dependence of absorption of water by desert
plants upon higher osmotic pressure of their sap. Thus Livinc-
STON” concluded, from determinations by the freezing-point,
boiling-point, and tissue curvature methods, that the saps of Cereus,
Echinocactus, and Opuntia “exhibit osmotic pressures no higher than
those commonly found in plants of the humid regions. For these
cacti at least, therefore, adaptation to desert conditions is not mani-
fest in increased concentration of the cell sap.”
From the foregoing account we may say that the cacti of the
Jamaica coast exhibit sap concentration of roughly the same order
of magnitude as do those of other regions. Possibly they are
somewhat higher than those of purely non-saline localities, but
until series in which standard methods ofsap extraction have been’
employed are available from other habitats this cannot be asserted
tobe the case. Certainly the cacti, with Bromelia and Bryophyllum,
are conspicuous exceptions to the general rule of high osmotic con-
centration in these coastal forms. ‘To this point we shall recur later.
Results
In the foregoing paragraphs we have shown that the sap of
the plant species of the Jamaican coastal deserts has an osmotic
** Cavara, F., Risultati di una serie di ricerche crioscopiche sui vegetati. Cont.
Biol. Veg. R. Ist. Bot. ice 41-80. 1905.
* MacDoueat, D. T., and Cannon, W. A., The conditions of parasitism in
plants. Publ. Carnegie Ins Inst. Wash. 129. IgI0.
_ ™Livineston, B. E., The relation of desert plants to soil moisture and evapora-
tion. Publ. Carnegie Inst. Wash. 50. 1906.
300 BOTANICAL GAZETTE [ocTOBER
concentration far higher than those of mesophytic regions, and quite
equal to if not slightly higher than those of the winter vegetation
of the Arizona deserts.
While determinations based on these species growing in other
environments are as yet too few to justify detailed discussion, it
seems most probable that the properties of their sap are due in part
to the local conditions and not merely to the existence here of a.
series of species characterized by high concentration.®
In the few cases in which constants for a species were obtained —
from the coastal flats and from the rocky slopes, the values from
the slopes are generally lower than those from the flats. Thus the
single determination on Caesalpinia vesicaria from the slopes gives
27.2 atmospheres as compared with 34.4, 34.9, and 37.0 from the
flats. Capparis ferruginea from the slopes gives 41.9 and 43.8
atmospheres as compared with 49.1 and 49.4 atmospheres when
growing on the flats. Jatropha gossypifolia gives 12.3 atmospheres
on the slopes as compared with 13.2 and 14.9 on the flats.
In the case of Prosopis juliflora and Achyranthes halimifolia, the
result is uncertain. The two collections of Achyranthes from the
slope gave 29.9 and 37.9 as compared with 29.8 and 38.7 atmos-
pheres for the flats. Prosopis on the slopes yielded sap with a
concentration of 32.3 atmospheres as compared with two readings
of 29.1 and 31.5 from the flats.
To what extent the osmotic concentration of the sap of the
sclerophyllous forms is influenced by the actual presence of salt
in the leaves can only be determined by special methods. The
leaves of some of the forms growing on the coastal flats, for example
Capparis ferruginea, are perceptibly salty to the taste; others are
not. It can hardly be doubted that the enormous variation in the
concentration of the leaf fluids of such forms as Batis maritima and
Sesuvium Portulacastrum, the leaves of which are practically re-
inforced water bags, is due primarily to electrolytes absorbed from
the soil. The fact that the various cacti are here characterized by
sap of low concentration, as when growing in true desert environ-
8 . * ‘3 . ve onl
A collection of the leaves of Guaiacum offcinale from Spanish Town ga ;
A=2.66, P=31.9 as compared with two constants each over 4° (50 a
in the coastal flats.
1917] HARRIS & LAWRENCE—TISSUE FLUIDS 301
ments, indicates that the absorption of any considerable quantity
of salts and their retention in solution is not a-necessary result of
existence in a saline substratum. Some physiologists have sug-
gested that the high osmotic concentration of the fluids of desert
plants is due primarily and directly to greater quantities of soluble
material in the substratum than generally occurs in regions of higher
rainfall. The validity of the conclusion is rendered highly improb-
able by the high concentrations demonstrated for the plants of the
rocky hillsides.
While in general it is better to reserve hypotheses concerning the
peculiarities of individual species until theoretical discussions of
their relation to environmental factors can be replaced by inductions
from actual quantitative data secured in the particular habitat
under investigation, it may be useful to other workers, especially
in the case of a problem requiring so many different kinds of
specialized observation in a habitat not easily accessible to most
botanists, to point out certain possible interpretations of the
observed phenomena.
The question of greatest interest is that ing the difference
in behavior of the several species of the same habitat, say the
Coastal flats. For example, the leaves of Prosopis and Caesalpinia
yield sap of a distinctly lower concentration than do those of
Guaiacum and the two species of Capparis. Jatropha gossypifolia
has sap of only about one-fourth of the concentration of that of
Batis maritima, with which it is so generally associated. The cacti
and the terrestrial bromeliad exhibit only a fraction of the freezing-
Point lowering shown by the hard and succulent leaves of the
arborescent and suffrutescent species among which they are
interspersed.
Any suggestion in interpretation of these phenomena must be
purely tentative and be substantiated by, or discarded on the
basis of, actual field studies. Those which are here called to the
attention of ecologists are not at all speculative, but merely
the result of an attempt to correlate the results of studies by a
number of specialists in the various fields of desert botany.
_ Sesuvium Portulacastrumand Batis maritima are both species with
highly succulent leaves. In both, the high osmotic concentration
302 BOTANICAL GAZETTE [OCTOBER
of the leaf sap must be due primarily to electrolytes absorbed
directly from the substratum. The difference between them, in
so far as facts are available, seems to be an inherent physiological
one. Sesuvium seems to be a form less tolerant of a highly con-
centrated soil solution than Batis. The local distribution of the two,
therefore, is not at all comparable, and the distinctly higher con-
centration in the leaves of Batis is probably attributable to this fact.
The only suggestion which can be made concerning the anoma-
lous position of Prosopis among the small trees is that it has a
more deeply penetrating root system which taps underflow water,
poor in solutes, derived by seepage from the neighboring lime-
stone hills.* From the extensive observations in the deserts of
southern Arizona it is known that the related species Prosopis
velutina is characterized by deep root penetration. Thus SPALD-
Inc” and Cannon” both note the wide horizontal and the deep
vertical distribution of the root system, which may reach a depth
of 8m. or over. CANNON” concludes that with uniform and pene-
trable substratum the species becomes a tree where the perennial
ground water does not lie at a depth greater than 50 ft.
Such differences as exist between the concentration in the
leaves of Prosopis and those of Batis maritima may be accounted
for on the grounds of a much higher concentration of salts in the
superficial soil layers.
It is interesting to note in this connection that Prosopis julifior a
from the coastal deserts gives values of osmotic concentration 1n
general agreement with P. velutina of the Arizona deserts. Thus two
determinations made on young leaves in the spring of 1914” gave:
Santa Catalina Mountains, A=2.08, P=25.0
Tucson Mountains, A=2.33, P=27.9
This suggestion. was originally made by SHREVE (loc. cit.) to account for the
presence of Prosopis in association — Batis — and other halophytes.
2 SPALDING, V. M., Distributi ts of desert plants. Publ. Carnegie
Inst. Wash. 113. 1
Cannon, W. A., The root habits of desert plants. Publ. Carnegie Inst. Wash.
131. IgII.
= Cannon, W. A., Some relations between root characters, ground water, and
species distribution. Science, N.S. 37:420-423. 1913.
3 Physiol. Researches 2:32. 1916.
1917] HARRIS & LAWRENCE—TISSUE FLUIDS _ 303
Hitherto unpublished determinations made in the summer of
1916 by LEamon and Harris give:
Santa Catalina bajada
Edge of arroyo, July 6, A=2.63, P=31.6
Same tree, August 14, A=2.40, P=28.8
Upper bajada, July 6, A=2.87, P=34.5
Mesa-like slopes, July 24, A=2.51, P*30.1
Surely no one will venture to assert on the basis of the available
data that the Jamaican Prosopis juliflora and the southwestern
P. velutina are sensibly different in osmotic concentration.
With regard to the cacti, which have been shown elsewhere in
this paper to have about the same concentration of tissue fluids as
those found for this group growing in other habitats, the following
points must be taken into account. The cacti are plants char-
acterized by a deeply penetrating anchoring root system and a far-
reaching superficially placed absorbing system. The evidences
upon which this statement is based are chiefly those presented by
Cannon in his large paper on the root habits of desert plants. If
the coastal species agree in this regard with the forms which have
been investigated, their absorbing organs are in contact with the
actually dryest zone of the substratum during periods of severe
drought, and with one physiologically dry, that is, characterized by
a soil solution of high osmotic concentration, during periods of
moderately abundant soil moisture.
Such are the conditions which result in the high concentration
found in Batis maritima, and one might, at first thought, suppose
that the cacti would also be subject to the same conditions. Two
additional factors, however, are to be taken into account: (1) the
cacti are organisms capable of rapid storage of water during tran-
sient periods of soil saturation, and its persistent retention during
* The point is splendidly illustrated by two photographs of Opuntia published by
CANNon (Amer. Nat. 40: cies fet: 2~3. 1906). MacDovcat and Spatpine (The
water balance of succulent p Publ. Carnegie Inst. Wash. 141. 1910) have
dealt with the problem in Sas aeart A number of other papers bearing more or
less directly upon the general pro blem of water absorption and storage in the cacti
have since appeared from the Desert Laboratory
304 BOTANICAL GAZETTE [OCTOBER
long periods of deprivation; (2) the rainfall in the Jamaican coastal
desert region is not distributed uniformly throughout the year.
During periods of heavy rainfall the salts would be highly diluted
or even largely washed out of the superficial soil layers in which
the absorbing roots of the cacti lie, thus permitting water intake
in quantities quite sufficient to maintain the plant until conditions
again become favorable for water absorption. Thus species may
differ very greatly in the relationship of their sap properties to
environmental factors. Two species may be rooted in the same
substratum, but because of differences in root penetration or in their
capacity for water absorption or retention in reality they may be
living in very different environments, or reacting quite differently
to the same environment.
Whether the hypotheses just advanced in explanation of the
great diversity of the constants determined on the sap of particular
species of plants growing in the same habitat be correct, can only
be determined by intensive observational and experimental studies
in the field. In the meantime they seem consistent with the
available facts of desert plant physiology.
Recapitulation
In the present paper, which is one of a series on the physico-
chemical properties of the tissue fluids of the plants of typical
vegetations, we have presented the results of determinations of the
freezing-point lowering of the tissue fluids of the plant species of the
Jamaican coastal deserts; have compared the constants secured
with those already available for the Arizona deserts and for meso-
phytic habitats; and have offered tentative suggestions concern-
ing the proximate causes of certain of the observed peculiarities of
individual species.
The deserts investigated constitute a small area on the southern
coast of the island, where not merely the reduction in the rainfall
due to the interception of the trade winds by relatively high moun-
tains, but peculiarities of the substratum, contribute to the rigor
of conditions limiting plant growth.
Two sub-habitats have been recognized, low-lying coastal flats
of finely ground detrital material, to a considerable extent impres-
917] HARRIS & LAWRENCE—TISSUE FLUIDS 305
nated with salts, and rocky limestone hills incapable of retaining
moisture or of deriving it by capillarity.
The vegetation of the coastal flats comprises a number of hard-
leaved trees, among which is a mesquite very similar to that of the
deserts of the southwestern United States, some thin and some
succulent-leaved halophytes, and a number of genera and species of
cacti which form a luxuriant-stand. The vegetation of the rocky
"hills is of a more arborescent type, consisting chiefly of dwarfed
broad-leaved trees with a number of small dwarf or half shrubs
which have few purely structural characteristics which would ally
them to desert plants.
Taken as a whole, the species of the Jamaican coastal deserts
show a concentration of their tissue fluids quite as high as, if not
slightly higher than, that of as nearly as possible comparable
growth forms in the Arizona deserts. The concentration of the
leaf sap of the ligneous forms averages about two or three times
that demonstrated in mesophytic regions.
ile the plants of the rocky slopes show high concentrations,
higher indeed than do those of the rocky slopes of the Arizona
deserts, their constants are distinctly lower than those of the species
of the coastal flats.
The sap of the cacti has only a fraction of the osmotic concen-
tration of that of the hard or succulent leaves of the trees and half
shrubs among which they are rooted. The succulent Bryophyllum
pinnatum and the terrestrial bromeliad Bromelia Pinguin show far
lower concentrations than do the other species. Furthermore,
Prosopis juliflora exhibits sap concentrations distinctly lower than
those of certain other of the arborescent species. These form the
extreme illustration of the fact that species of the same habitat
show marked differences in sap properties. Suggestions concerning
the underlying causes of such differences are offered.
STATION FoR EXPERIMENTAL EVOLUTION
Cotp Sprinc Harzor, Lone Istanp, N.Y.
A NEW METHOD OF STUDYING PERMEABILITY
Ss. C. Broexs
(WITH TWO FIGURES)
The writer™ has shown the desirability of a study of permeability
by some method which should be entirely independent of other
methods, and yield data the interpretation of which need not depend
upon any unverifiable assumptions. A method is here presented
which seems to fulfil these requirements. It has proved to be
exceedingly reliable; and the experiments point clearly to the errors
previously made in the interpretation of the data secured by many
methods, and to the validity of the conclusions based on the
evidence of certain others.
Method
The method depends upon diffusion of salts or other substances
through a diaphragm of living tissue. For this purpose fronds
of one of the common kelps of the New England coast, Laminaria
Agardhii (formerly identified as L. saccharina), proved to be
extremely satisfactory material because of absence of air spaces
in the tissue, ease of manipulation, resistance to adverse conditions,
and especially because it was possible to secure thin sheets of tissue
in which there were no wounded surfaces in contact with the solu-
tions.
The method of experimentation was as follows. Sections of
glass tubing of 18 mm. internal diameter were cut; one end of each
piece was flared and the end ground flat. The resulting “cells”
were either 2.5 cm. or 4 cm. in length, and were combined in pairs,
each consisting of one long and one short cell (fig. 1, A, B)- The
unground end of the longer cell was closed by a rubber tube and
pinchcock (fig. 1, C, D). Disks were cut from the fronds of Lamt-
naria of such a size as nearly to cover the ground ends of the tubes.
Brooks, S. C., Methods of studying the permeability of protoplasm salts.
Bor. GAz. 64:230-249. 1917.
Botanical Gazette, vol. 64] [306
1917] BROOKS—PERMEABILITY 307
In the experiments with living material the surface of these
disks was quickly dried with filter paper, the disks (fig. 1, Z) placed
between the ground ends of a pair of cells, and the joint made tight
with a stiff cement consisting of a mixture of vaseline and beeswax
(fig. 1, F). Thus there were formed two cells separated by a dia-
phragm of Laminaria tissue. The cell supplied with the rubber
tube and pinchcock (hereafter called the “lower cell’’) was then
filled with solution and the pinchcock closed, care being taken that
no air bubbles were included in the cell. The apparatus was then
inverted and the upper cell filled with solution, covered to check
evaporation (fig. 1, G), and set in a suitable
support. During these operations each disk
was in contact with the air less than two
minutes, which was not sufficient to cause any
appreciable drying-out of the tissue.
In order to obtain dead tissue for experi-
ments on the permeability of the intercellular
substance, living disks were exposed, after cut-
ting, to an atmosphere saturated with chloro-
form vapor at room temperature for 16-24
hours. They were next exposed to the air
about one hour to allow the complete evapora-
tion of any chloroform which remained in the
tissue, and then placed in a large volume of sea oe
water for about 24 hours to allow the establish-
ment of equilibrium between the electrolytes of the sea water and
those in the dead cells. At the end of this time the surface of the
disks of tissue was dried with filter paper, and the apparatus set up
as in the experiments with living material.. Tissue which had died
a natural death gave results in every way similar to those given
by tissue killed in this manner.
The permeability of the tissue was shown by the rate of passage
of salts through the diaphragm as shown by diminution of the
difference of concentration between the solutions in the upper and
lower cells. It is possible to measure rapidly, and with extreme
accuracy, slight changes in the concentration of the solutions in
either cell by determining the change in electrical conductivity.
This method was therefore employed.
308 BOTANICAL GAZETTE [OCTOBER
The solution used in the lower cells was either sea water or a
pure salt solution of the same conductivity; while the upper cells
contained a solution of half the concentration of that in the corre-
sponding lower cell. Solutions of equal conductivity were used
in order to facilitate comparison with the work of OSTERHOUT.’
Sources of error
In order to obtain accurate data, the following precautions were
taken:
1. The solutions were made up with distilled water, which had
a specific conductivity of about 2X10-*® ohms. The sodium
chloride used was Baker’s “analyzed”; the calcium chloride,
Kahlbaum’s; and the lanthanum nitrate, Eimer and Amend’s
“Tested Purity.” For this work an error of 1 per cent in the con-
centration of the solutions was considered allowable.
2. In order to prevent dissolving of electrolytes from any part
of the apparatus, the cells were made of Durox glass, and both
cells and rubber thoroughly steamed immediately before each
experiment. An apparatus of this type, set up with no Laminaria
tissue, but with a thick layer of the vaseline-beeswax cement, and
filled with distilled water, gave off only traces of electrolytes. The
change in conductivity of the water in such a cell during 48 hours
was equivalent to an increase of concentration of sodium chloride
of less than 1X10-7M. Dissolving of electrolytes from the
apparatus has therefore no significance in the experiments.
3. It was necessary to eliminate the influence of temperature.
As it was impracticable to conduct the experiments at constant
temperature, the cells were placed outdoors, the temperature vary-
ing from —3° to +9° C. This amount of fluctuation produced no
appreciable change in the rate at which salts passed through the
tissue, and the low temperatures were exceedingly favorable to the
maintenance of normal permeability.*
? Unpublished data of OstErRHouT show that differences of osmotic pressure
the magnitude of those produced by the use of solutions of equal conductivity bare
little effect on the permeability of Laminaria during the ape of time occu y
these experiments.
3 Laminaria lives much longer when the temperature is low. While it may be
en hy alive under laboratory conditions several weeks ‘at o° C., it perishes rapidly at
1917] BROOKS—PERMEABILITY 309
4. The Laminaria thallus is made up of masses of protoplasm
(the cells) imbedded in a gelatinous intercellular substance. From
this intercellular substance, in which the salts are present in the
same concentration as in sea water, the salts will diffuse out intoa
surrounding medium, and will alter its conductivity if it be other
than that of sea water. From the protoplasm, also, a similar
diffusion may take place, which for convenience may be designated
as “exosmosis.”’
That there is actual passage of salts through the tissue was
shown by the fact that the conductivity of the more dilute solution
always increased, while that of the more concentrated solution
decreased to a corresponding degree. There was no appreciable
change in the volume of either solution even during experiments
whose duration was greater than 24 hours. The relative amounts
of increase in the upper cell and of decrease in the lower cell, as
found in the experiments, were in fair agreement with those calcu-
lated. If a given amount of salt passes from one salt solution to
an equal volume of another solution having half the concentration
of the first, the percentage of increase in the concentration of the
latter will be double the percentage of decrease in the former. If
there be a difference in volume between the two solutions, the
change caused by the addition or removal of a given amount of
salt will be inversely proportional to the volume. Thus, in one
experiment the increase in concentration in the upper cell was
I per cent per hour, while the decrease in the lower cell was 0.26 per
cent per hour. Since the volume in the upper cell was 5.4 cc. as
compared with 12.5 cc. in the lower, and the concentrations were
as 1:2, the expected ratio between the changes in the two cells
would serge SAP a4. 6; while the observed ratio was ao 3. 8.
The premise was reasonably satisfactory, and it therefore
could be assumed that changes in the concentration of the solutions
in the upper cells would be nearly proportional to the amount of
salt passing through the diaphragm. Two modifications of the
method, however, were sufficient to eliminate entirely the errors
due to both diffusion and exosmosis. The error due to diffusion
of salts from the intercellular substance was eliminated by filling
310 - BOTANICAL GAZETTE [OCTOBER
the cells, when first set up, with half-strength sea water in the upper
cell and sea water in the lower. Thirty minutes was ample for the
establishment of a steady diffusion gradient through the tissue
between the two solutions. The upper solution was then replaced
by fresh half-strength sea water, after which regular readings were
taken. In order to eliminate the error due to exosmosis from the
protoplasm, such as might be occasioned by toxic salts, 3 controls
out of each set of 11 to 13 simultaneous experiments had the more
dilute solution in both cells. At the end of the experiment the
average conductance of the solution in the upper cells of the controls
was taken as a standard of measurement, the average conductance
of all the other upper solutions being divided by this figure in order
to obtain the percentage which expresses their gain as compared
with the control. The figures which were obtained in this manner
measure the amount of salt which has passed through the tissue,
while the errors due to exosmosis from the protoplasm as well as
those due to diffusion from the intercellular substance are elimi-
nated.
5. We must eliminate the error due to variations in the thick-
ness and maturity of the disks of tissue from different fronds, and
also that due to variations in the area of tissue through which salt
can pass (such as might be introduced by unavoidable smearing
of the cement over the surface of the disks).4 In order to eliminate
all of these errors, controls were established in the following man-
ner. After a preliminary half-hour with half sea water in the
upper and sea water in the lower cell, the upper solution was
replaced with 5.4 cc. of fresh half sea water, and the rate of change
of conductivity determined at the end of 2 hours. Both upper and
lower solutions were now replaced with solutions of the salt to be
investigated (the fresh solutions having the same conductivity as
those which they replaced), and the rate of change of conductivity
determined after a further period of 2 hours. By dividing the
4 A single experiment was conducte d to determine the influence of frond thickness.
The results were entirely negative. This is in accord with the results secured by ABEL
(Aset, J. J., Rowntree, L. G., and Lurver, B. B., On the removal of diffusible
substances from the circulating blood of living animals by dialysis. Jour. Pharm.
and Exp. Ther. 5:275. 1914.), who found that onaeor at electrolytes through 4
collodion membrane was independent of the thickness of
1917] BROOKS—PERMEABILITY 311
figure obtained for the salt in question by that for the control
period of the same disks of tissue, we obtain a figure (given in the
ratio column of table II) from which all errors due to individual
variations of the disks of tissue are eliminated.
6. The method for the determination of the conductance of the
solutions was as follows. The solution was poured from the cell
into a U tube of such dimensions as to give a conductance of the
order of magnitude most accurately determinable, namely, about
1500-2000 ohmsX1077. The U tube was nearly immersed in a
constantly stirred water bath whose temperature, determined to
o%05 C., varied less than 0°8 C. in any one set of readings. A
temperature correction of 2 per cent per degree Centigrade was
applied to the actual readings to reduce them to the average tem-
perature of the set, and the results calculated from the corrected
readings thus obtained. A slide wire bridge, a standard 1000-ohm
bifilar resistance (supplied with current from the secondary of a
Nernst string inductorium at about 300-500 oscillations per second),
and a telephone as the zero instrument were used in the customary
manner to measure the resistance between bright platinum elec-
trodes immersed in the solution at the opposite ends of the U tube.
The distance between the electrodes was fixed. The readings had
an error less than 0.1 per cent. The check experiments in half-
strength sea water usually gave an agreement of corrected readings
within 0.05 per cent. It will be seen that this degree of accuracy
was ample for the purpose.
Results
It is desirable first to find out how fast the various salts pass
through the intercellular substance, and whether there is any
selective permeability due to any source other than the protoplasm.
The data presented in table I show that the cell walls intercell
substance of Laminaria are permeable to the salts used, and that
the passage through the walls is nearly independent of the nature
of the diffusing salt. In dead material the change of concentration
is so rapid that owing to the decrease in the concentration gradient
the rate of passage of salts through the tissue decreased, as is shown
by the lower rate for the longer periods in both sea water and sodium
312 BOTANICAL GAZETTE [OCTOBER
chloride. It is necessary, therefore, to draw our conclusions from
the results of periods of equal length only. The relative permeabil-
ity to different salts will then be represented by the following
figures: calcium chloride 2.2, sea water 2.2, lanthanum nitrate
2.1, sodium chloride 2.1. |
TABLE I
PERMEABILITY OF DEAD TISSUE OF Laminaria
: f con
Solution in upper cell| Solution in lower cell | a _suctiviy . pers
Half sea water...| Sea water...... ‘5 1.8
CaCh, 0.14 CaCl, 0.28 M. 4.5 2.2
lf sea water Sea water...... I2 ee
‘ Basra eewOumaeeee, Vee rs *.2
NaCl, 0.26 M...| NaCl, o. ot 5 2.0
alf sea water...| Sea water...... 12 1.2
La,Cl, 0.05 M..| La,Cle, o ae 4.5 2.1
NaCl, 0.26 M...| NaCl, 5 OE, 4.5 2.1
It appears probable that the slightly lower rate of diffusion of
sodium chloride may have been due to a slight irreversible decrease
in the permeability of the intercellular substance caused by the
lanthanum nitrate, by which the tissue had been bathed imme-
diately previous to the experiment with sodium chloride. This
would be in accord with unpublished data secured by OSTERHOUT
by determination of the conductivity of the tissue.
The differences which might be expected to arise as an expres-
sion of the diffusion coefficients of the salts are evidently of so
small an order as to fail to influence appreciably the rate of diffusion
through dead tissue. In view of the very imperfect state of our
knowledge of diffusion coefficients, it would be unprofitable at the
present time to attempt any further explanation of the influence
of that factor in our experiments.
It will be seen from the data given in table II that the presence
of living protoplasm greatly decreases the permeability of the tissue
as a whole. Living protoplasm offers, therefore, a very consider-
able resistance to the passage of salts. That it is not normally
(in sea water) impermeable to salts will appear from the following
considerations. The permeability of the protoplasm for conven-
1917] BROOKS—PERMEABILITY 313
ience may be considered as the amount of salt passing through the
tissue, expressed as the percentage of the amount passing through
tissue bathed by sea water, as shown in the ratio column of table II.
If the protoplasm be assumed to be wholly impermeable to salts
of lanthanum, the figure 0.45, expressing the permeability of the
tissue as a whole, would in this case represent diffusion through
the intercellular substance only. Since this part of the tissue has
been shown (cf. table I) to have no appreciable selective permeabil-
ity, we may assume that not more than 0.45 of the permeability
of the tissues to sea water, which is 1.07, is due to passage of salts
TABLE II
PERMEABILITY OF LIVING Laminaria
First PERIOD SECOND PERIOD Ratio
F) 2 3
Be U 3 Dura me Dura wees ae
5] - ~ poy
PE seltica pc-aerdl ond ee 58 Upper solution|Lower solution “ago eg 3 Z z Z
gm aeae geak! Sia
butt OF i &
18..| Half se. a. 2:05 | 0.73 | Half sea Sea water | 2:00 | 0.78 | 1.07
water water water
19.. oi i 2:00 | 0.79 | NaCl, NaCl, 2:00 | 1.1m | 1.41
°0.26M °o.52M
22.. . x 2:06 | 0:73 | CaCl, CaCl,, 2:02 | 0.51 | 0.70
0.14 0.28 M
17a. « “ 1:35 | 0.73 | Las(NO,)s, | Las(NO,)s, | 1:35 | 0.33 | 0.45
0.05 M ‘o.10M
through the intercellular substance. There remains 1.07—0.45=
©.62, which represents that part of the salt which passes through
the protoplasm. In sea water, therefore, a minimum of on or
58 per cent of the salt, passes through the protoplasm, but the
exact significance of this figure is doubtful owing to the arrangement
of the protoplasmic masses in the tissue.
In order to show the order of magnitude of the total diffusion
through the living tissue, the results may be expressed in terms
of the amount of salt in gm. molecules passing through 1 sq. cm. of
tissue per hour. Ignoring the exceedingly slight change in molec-
ular conductivity induced by such small changes of concentration,
314 BOTANICAL GAZETTE [ocTOBER
the conductivity will be proportional to the concentration, and a
change of 1 per cent in the conductivity of a 0.26 M solution may
be assumed to indicate an increase of 0.0026 M in the concentra-
tion. An increase of this size in 5.4 cc. of solution will necessitate
the addition of 5 _—
5 Oo: 0026, or 0.0000140 gm. molecules of salt.
If we divide oe pane chisel: | in this manner for the various
salts, by the area of tissue in sq. cm. through which salts can pass,
we obtain the figures given in table III. The figure for sea water
was obtained by assuming all of its conductivity to be due to
sodium chloride; but since sea water contains about 12 per cent
of its electrolyte as salts of bivalent elements, which have a higher
molecular conductivity than sodium salts, its actual molecular
content is less than that of a sodium chloride solution having the
same conductivity, and the figure given in table U1i is thus slightly
too high.
TABLE III
GRAM MOLS DIFFUSING PER SQ. CM. PER HOUR
THROUGH LIVING Laminaria
Upper solution Lower solution po Se ng
sea water..... MELO ee a ©.0000425
NaCl, o - = Wane ee o,53 Mo... 0.0000610
CaCl, ort Mc: CaCl, 0.28 M..:... ©.0000150
La (NOs, °. ee M..| La (NO,\«, 0.10M...| 0.0000034
The data of tables II and III also show that there is a selective
permeability to the salts used. Sodium chloride is allowed to
pass through the tissue most rapidly, the salts of sea water next,
calcium chloride considerably less rapidly than sea water, and
lanthanum nitrate least of all. That the effect is produced in large
part by the kations, as was to be expected, is shown by the fact
that preliminary experiments with lanthanum chloride (lacking
the preliminary comparison period in sea water) showed a per-
meability comparable with that to lanthanum nitrate. Thus in
one experiment with lanthanum chloride the change of conduc-
tivity of the upper solution was 0.30 per cent per hour, while that
quoted for lanthanum nitrate is 0.33 per cent per hour. Whether
1917] BROOKS—PERMEABILITY 315
protoplasm is at all permeable to lanthanum salts cannot be decided
with the data furnished by these experiments.
It might be supposed that the protoplasm was normally more
permeable to sodium chloride than to the other salts of sea water,
and that therefore when bathed by pure sodium chloride solution
more salt would pass through the diaphragm. On the assump-
tion that the tissue is permeable only to the sodium and potassium
chlorides, the molecules of which constitute 88 per cent of the
molecules of salt in sea water, the rise in permeability on substitu-
tion of sodium chloride solutions for sea water would be only that
from 88 to 100. The observed rise is much greater, namely, from
76 to 100, and in addition it must be remembered that the calcium
and magnesium salts of sea water are probably able to penetrate
the tissue to some extent. Sodium chloride must increase the
permeability of the tissue therefore.
By analogy, it might be assumed that the permeability of the
protoplasm decreased under the influence of calcium and lanthanum
salts. In order to obtain more exact information in respect to this
question, a set of experiments was conducted in which the per-
meability was determined during successive periods of treatment
with a given salt. The solutions in both the upper and lower cells
were renewed at the beginning of each period. The results are
shown in table IV and fig. 2.
From these experiments it will be seen that the increase of
permeability due to sodium chloride is progressive, and that it
leads in the course of about 4 hours to a permeability of the tissues
corresponding to that of dead material. The effect of calcium
chloride, on the other hand, is to cause a temporary decrease in
permeability, followed by a rise which at the end of about 12 hours
leads to a permeability comparable with that for dead material.
At the end of this time the material had assumed the green color
characteristic of dead material.
The experiment with sea water was conducted under conditions
extremely unfavorable to the maintenance of normal permeability,
the temperature rising to 14° C. during the third and fourth periods.
Partial recovery is shown in the succeeding periods during which
the temperature decreased. The last period was begun about 24
316 BOTANICAL GAZETTE [OCTOBER
hours after the beginning of the experiment, and shows that the
tissue, which had only partially recovered its normal permeability,
TABLE IV
PROGRESSIVE CHANGES IN PERMEABILITY OF TISSUE OF LIVING Laminaria; EXPRESSED
RATE OF CHANGE OF CONDUCTIVITY OF SOLUTION IN
UPPER CELL, IN PERCENTAGE PER HOUR
bar gating enor ema UPPER SOLUTION, NACL, 0.26 M;|| Upper SOLUTION, CACIs, 0.14 M;
SEA WATER : LOWER SOLUTION, NACL, 0.52 M || LOWER SOLUTION, CACL:, 0.28 M
D Rate Dura- | Rate Dura- | Rate
tion of |/Period begun at} _ tio of
in min. ange in mi
ee ch a Pi smc ictondces tm Sige change
6:45 A.M..| 120 | 0.67 || 2:40 P.M...,) 120] 1.21 || 9233 A.M....| 122 | 0-§1
Q:15A.M..| 124 | 0.78 || 5:10P.M...| 150 | 2.30 |l12:05 P.M....| 124 | 0.82
II:45A.M..| 22r | 1.02 || 8:15 130 | 2.50 || 2:45 P.M.. 121 | 0.69
Siew eee | eee ee ea ec as ek 5:25 P.M.. 120.) 137
me Mal S70 | OBE er eo he pans 8:10 P.M.. 135 | 2-95
He We ke ee es | ae eo Oe at ee Ge, hi Se eh be cet
oeerlererre
ee ee ee
1 2 3 + 6 ry Ss 2 Hours.
suffered no further injury during the period of low temperature
(o-4° C.) intervening between the fifteenth and twenty-fourth
1917] BROOKS—PERMEABILITY 317
hours. The disks were still brown and apparently uninjured even
after 48 hours in the apparatus. Certain experiments with lan-
thanum salts indicated that the effect of lanthanum would resemble
that of calcium, differing chiefly in that the alterations of per-
meability would take place more rapidly.
Summary
1. The protoplasm of Laminaria is normally permeable to the
salts of sea water.
2. Sodium salts cause an increase of permeability which cul-
minates in death.
3- Calcium and lanthanum salts cause a decrease in per-
meability, followed by an increase which culminates in death.
LABORATORY OF PLANT PHYSIOLOGY
HarvVARD UNIVERSITY
EVAPORATION RECORDS FROM THE GULF COAST
LAURA GANO AND JEROME MCNEILL
(WITH FOUR FIGURES)
In connection with field work in northern Florida, undertaken
to determine the composition and limits of certain gulf coast forest
associations and their relations in succession, and following the
instructions of LivincsTon,’ FULLER,? and the work of others in
the north and west, records of the daily rate of evaporation in
several of the typical plant associations were kept, some of them
running through a period of 19 successive months. The Livingston
rain-correcting atmometers were used and care was taken to follow
the directions for their operation in all particulars. It was planned
to visit each station once in two weeks, and this was carried out
with few interruptions.
Station no. 1 was in an upland hammock forest on Norfolk Fine
Sandy Loam. Magnolia grandiflora, Fagus grandifolia caroliniana,
and Acer floridanum Pax (or Acer saccharum floridanum Sarg. Silva —
N. Am.) were the chief trees, with an undisturbed growth of young
trees of these and other species and of mesophytic shrubs and
herbs. The apparatus at this station suffered various mishaps, and
the record is broken, but from January to May 1913, which includes
the times of extreme minimum to maximum evaporation for all the
stations (except that of Pinus palustris), the record is complete.
Station no. 2 was in an upland oak forest on Orangeburg Fine
Sandy Loam, 2.5 miles west of Tallahassee. In this forest nine-
tenths of the trees were deciduous, with Quercus falcata, Q. stellata,
and Carya alba predominating. Cornus florida was common, but
Q. virginiana and Ilex opaca (broad-leaved evergreens) were rare.
Myrica cerifera, Rhus copallina, Ilex vomitoria, Ceanothus ameri-
canus, Aralia spinosa, Vaccinium stamineum, Callicarpa americana,
* Livincston, B. E., Evaporation and plant habitats. Plant World 11:1-9-
1908; Operation of the porous cup atmometer. Plant World 13:111-119- 1919-
2 Futter, G. D., Evaporation and plant succession. Bor. Gaz. 52: 193-208.
Igtt.
Botanical Gazette, vol. 64] [318
4
1917] GANO & MCNEILL—EVAPORATION RECORDS 319
and Viburnum rufidulum were the principal shrubs about the
station and made a rather close shrubbery throughout the woods.
The list of herbs shows nothing especially distinctive in the way of
species, as they are practically the same as those of the beech and
short-leaved pine forests in which stations 3 and 4 were located.
Station no. 3 was in an upland short-leaved pine forest about 1
mile north of Tallahassee, on Orangeburg Sand. The mature trees
were almost entirely Pinus echinata, but this wood was well
advanced in the undergrowth toward the oak-hickory stage; the
young half-grown trees of Quercus falcata, Q. stellata, and Carya
alba, and also of Q. virginiana and some Fagus grandifolia
caroliniana, made one story, under which was a lower growth of
Quercus nigra, Q. laurifolia, QO. marilandica, Crataegus spp., Prunus
angusitfolia, Cornus florida, Nyssa sylvatica, Vaccinium arboreum,
Callicarpa americana, and Viburnum rufidulum, with numerous
lianas as Smilax glauca, S. pseudo-china, Cissus spp., Vitis rotundi-
folia, Gelsemium sempervirens, and Lonicera sempervirens. Common
herbs of the station vicinity were Arisaema Dracontium, Oenothera
biennis, Sanicula canadensis, Gerardia purpurea, Mitchella repens,
Eupatorium album, and Chrysopsis mariana.
Stations 2 and 3 were operated for 19 months continuously
without a break or mishap.
Station no. 4 was in a beech wood about one-fourth of a mile
east of the station in the pine forest. To the west and south of this
forest was a short-leaved pine wood in a still later stage than the one
in which station 3 was placed. The proportion of deciduous trees
was larger and the trees older, while the undergrowth was much less
dense, which may largely be accounted for by the fact that this
wood had been stocked with hogs and cattle for some years. To
the north its character changed quite abruptly, the pines being few
and the number of mature deciduous trees not large, but the under-
growth was very dense. Throughout this wood (an area of some
40 acres) were scattered beeches of all ages. Magnolias were less
common. The beech opening in which the station was located
apparently had once been somewhat swampy, although but little
lower than the rest of the ground and scarcely wetter except after
heavy rainfalls. Asa whole the forest was level and formed part of
320 BOTANICAL GAZETTE [OCTOBER
a level hilltop. The soil was mainly Orangeburg Sand, which is a
transitional type between the Orangeburg and Norfolk Fine Sandy
Loams, and which, as stated in the soil survey, is occasionally found
in small isolated patches within the Orangeburg Loam areas, occu-
pying slight elevations which have not suffered from erosion.
The evaporimeter was placed in the portion of the woods freest
from shrubs or undergrowth of any kind, there being comparatively
few herbs in the vicinity, those noted being mainly the same as
those of the open pine wood, except that the fireweed (Erechtites
hieracifolia) was common. This station suffered several interrup-
tions during the 18 months of its operation, owing to the pasturing
animals and other causes.
The four stations described were all on the hills or elevations
over 100 ft. above sea level, and none of them suffered from frost.
Station no. 5 was established in September 1912, about 5 miles
southwest of Tallahassee, on low sandhill soil, a strip of gently
rolling yellowish sand, covered with a dense growth of: scrub
oaks, only an insignificant part being under cultivation. It has
doubtless been a shoal, extending east and west parallel with the
edges of the abrupt upland to the north which once formed the
shore line. This sandhill area is characterized everywhere by 4
very definite as well as limited tree flora. There are 3 scrub oaks
and 2 pines, the latter being scattered. Quercus catesbaea, Q. marga-
retta,Q. cinerea, and the long-leaved pines, Pinus palustris and P. car-
ibaea, are the species. The chief undershrubs near the station were
Asimina pygmaea, Vaccinium arboreum, and V. corymbosum.
Ascyrum hypericoides was also noted at this station and appears
to be generally ubiquitous, although frequent rather than abundant.
The herbs were Asclepias tuberosa, Scutellaria integrifolia, Gerardia
purpurea, Eupatorium aromaticum, and Liatris laevigatus.
Although the sandhill region is very sparsely inhabited, the records
from this station happened to be frequently interrupted by meddle-
some hunters as well as by fire, frost, and a cyclone. In the effort
to keep the apparatus hidden it was twice moved. The cup was
broken by frost on November 28, 1913.
Station no. 6 was in a long-leaved pine forest on Norfolk Sand,
4 miles southwest of Tallahassee and a quarter of a mile north of
1917] GANO & MCNEILL—EVAPORATION RECORDS 321
Station no 4. At this station the evaporimeter was broken by
frost once in the second winter of its history, on January 11; it
was shot to pieces once; and was once in the immediate path of a
June cyclone which blew down most of the trees in a track 800 ft.
wide. By this storm the cup was demolished but the reservoir
was unbroken. The location was then changed a few rods to the
east. This station was peculiar in that the trees were essentially
like those of the Leon Sand station (no. 7) near Lake Jackson, and
the herbaceous plants like those on the sandhill soil. At the outer
border of this soil, where the Norfolk Sand and the sandhill join,
the scrub oaks gave way abruptly, the line between the two soils
being generally as sharp as if the planting had been artificial.
e Leon Sand station, no. 7, was in operation more or less
continuously for 18 months, being broken by frost once the first
winter and twice during the second winter; it was also once in the
path of a fire. This Leon Sand is situated 9 miles northwest of
Tallahassee, being a strip of long-leaved pine forest about 200 yards
wide. This small area is bordered on the north by a slough which
is directly bordered by Norfolk Sand, and to the south the soil is
the Norfolk Fine Sand, each with characteristic vegetation. This
strip of the Leon Sand is an outlying neck of a larger area of the
same soil 2.5 miles wide and 1 mile long, the only area of this
particular soil in the northern part. of the county which is accessible
to the railroad. However, in its growth it is typical of the larger
area of the flatwoods to the southeast. This soil, wherever it
occurs, is very level and poorly drained and therefore excessively
wet a large part of the year. Station no. 7, therefore, was on the
wettest soil of any, and its vegetation should be compared with that
of station no. 6, which also supported a long-leaved pine forest on
the Norfolk Sand, one of the driest soils of the region. The wood on
the Leon Sand was very open and the destruction caused by turpen-
tining had still further thinned it. Owing partly to frequent fires
and partly to the general quality of the soil and the drainage, the
undershrubs were very low, seldom exceeding 2 ft. in height. The
forest floor was sparsely covered with wire grasses. Apart from
the pines, the trees noted about this station were occasional small
specimens of deciduous trees, as Quercus falcata, Q. virginiana, Q.
322 BOTANICAL GAZETTE [OCTOBER
nigra, Liquidamber styraciflua, Acer rubrum tridens, and Nyssa
sylvatica biflora. The undershrubs were Quercus myrtifolia, Q.
minima, Pyrus arbutifolia, Rubus villosus, Rhus copallina, Ilex
glabra, I. lucida, Hypericum fasciculatum, Vaccinium virgaium
tenellum, Viburnum nudum, and V. molle. A common liana was
Gelsemium sempervirens, but the most common plant of all was
Serenoa serrulata (saw palmetto). The herbs about this station
make a distinctive list, the majority being species of Compositae,
as Helianthus angustifolius, Rudbeckia laciniata, Aster Tradescantt,
Solidago fistulosa, and Bidens bipinnata; there were also Polygala
lutea, Viola lanceolata, Sabatia gracilis, S. lanceolata, Pinguicula
lutea, and Valerianella radiata.
Stations no. 8 and no. g were located in October 1913 in the
meadow of the Ocklocknee River. One was placed in a willow
growth on the south bank, the apparatus being located in the outer
border of the narrow strip of trees edging the stream and 5 or 6 ft.
above the water at its normal stages. At this point a strip of bare
sand, 15-20 ft. wide, separated the willows from a birch zone.
Immediately bordering the river this meadow strip was about one-
fifth of a mile wide, bounded on the east by a strip of Norfolk Sand
with the long-leaved pines. The area occupied by the willows was
subject to frequent overflow and no other plants seemed able to
maintain themselves permanently in this zone. The growth here
was not luxuriant, few of the trees exceeding a height of 10 or 12 ft.
The records from these stations were interrupted by frost about
December 21, 1913, and again on January 18, 1914, while from
February 1 to March 28.the apparatus was covered by water tw0-
thirds of the time and no records were secured. The birch station,
4 ft. higher and 15~20 ft. farther inland than the willow station,
suffered similar interruption, except that the interval due to the
flood was two weeks shorter and the apparatus was reestablished
March 15, at which time the willow station was still completely
under water. On the whole, the growth here was more luxuriant,
although few of the trees had trunk diameters greater than 6
inches, or height greater than 15-20 ft.
Laboratory examination of each of the soils at the several
stations was made to determine the organic content and general
1917] GANO & MCNEILL—EVAPORATION RECORDS 323
character. The Orangeburg Fine Sandy Loam soil from the
Spanish oak-post oak station, when dried, was a dark brownish
gray. It is an excellent soil, rich in humus, and the drainage in the
locality of the station was good. The soil from the short-leaved pine
station was a medium brownish gray, similar to the preceding but
containing a larger proportion of sand (Orangeburg Sand), and less
humus. The soil from the beech wood was the same according to
the classification of the United States Soil Survey Report, and it
resembled that of the pine wood in the samples taken in the course
of this study, but both soil and subsoil were of a brighter reddish
tinge. The area of the beech station was hardly so well drained as
that of the pine wood. The soil from the Pinus palustris forest on
Norfolk Sand was very similar in color (both soil and subsoil) to
that of the short-leaved pine, but contained decidedly less clay,
separating in loose grains when dry, while the other dried in small
lumps. It was also less rich in humus. The drainage was excellent
to excessive. The soil from the scrub oak forest (which adjoined
the preceding on the south) was very similar to Norfolk Sand in
texture but a brighter red and perceptibly poorer in humus. The
soil from the Leon Sand station was a medium gray sand with a
very small admixture of organic materials. It was too wet for
agricultural crops.
The evaporation records from the mesophytic forest (station
no. 1), during the time it was steadily running, showed a consistently
lower average and actual rate than any other station. The
minimum monthly rate for this station was 6.05 cc. per day in
January. The actual minimum was 4.5 cc. in January. The
maximum monthly rate was 10.27 cc. daily in April, and the actual
maximum was 11.9 cc. the first of May. The mean average rate
for the 4 months covering the time from the minimum to the maxi-
mum was 8.5 cc. per day, an interesting result in comparison
with the record of evaporation for beech-maple forests in the
north.
Station no. 2, the Spanish oak-post oak forest, in comparison,
gave a record of 9.90 cc. per day for the same period of the same
year. The average of this station for 18 months’ continuous and
unbroken record, however, is 14 cc. daily. The minimum monthly
324 BOTANICAL GAZETTE [OCTOBER
average is 9.94 cc. per day in December, and the maximum monthly
average is 22.20 cc. daily in April. The actual minimum during
the 18 months was 7.01 cc. in October, and the actual maximum
was 29.28 cc. in March.
The short-leaved pine station, no. 3, averaged 11.67 cc. per day
for the same period of the same year as given for stations nos. 1 and
2; and for an 18 months’ unbroken record, 14.22 cc. perday. The
minimum monthly average was 8 .83 cc. per day in January, and the
maximum monthly rate 19.7 cc. daily in April. The actual
minimum was 5.18 cc. in January, and the actual maximum was
25.04 cc.in May. Comparison of stations 2 and 3 thus shows the
averages as based on the yearly rate to be very similar. If, how-
ever, a comparison be made of their rates during the two general
periods for deciduous trees, namely, with full foliage and without
full foliage, or summer and winter (from June to November, and
from November to June), the comparison shows that the June to
November season gave a rate of 12.49 cc. daily for the oak forest,
and of 13.8 cc. daily for the pine forest; while the winter rates
(November to June) were, respectively, 15.69 cc. and 13.70 CC.
This demonstrates a greater evaporation in winter in the deciduous
forest, and the greater evaporation in summer from the pine forest.
However, the similarity in the yearly rate, covering as it does the
extremes of the two years, shows that the evaporation in the two
forests was not greatly different, and this may seem related to the
fact that at both stations there was an abundance of shrubbery of
similar composition; if anything, that of the pine wood, being in
two stories, was the thicker, and ay telescoping of these two
associations was conspicuous.
The beech forest, which had been burned and pastured, gave
an average result of 16.63 cc. daily for the whole period of 18
months (with one break in the record for November to December
1912), an average of 11.21 cc. per day for the period from January !
to May 1, 1913, and an average of 13.4 cc. for the summer (full
foliage) period. This last compares with the same average of the
pine wood, showing a similarity between the pine forest and the
pastured beech wood. June shows the minimum monthly rate
for this forest, and March the maximum (fig. 1).
1917] GANO & MCNEILL—EVAPORATION RECORDS 325
Station no. 5, that of the scrub oaks, gave 15.52 cc. daily for
18 months, and 15.30 cc. daily for the period from January to May
1913. For the summer (June to November) the average was
13-95 cc. daily, corresponding to the short-leaved pine and the
pastured beech wood. The winter rate was 14.1 cc., intermediate
between that of the oaks and pine. The period of greatest evapora-
tion was April; while December, January, and February showed
| |
20 L {atl
ie 7 ix | 4
/5 i \ | “INN ; C
ot ELS be Oe
yee c re va Mb f ” 1 v
|_Lo Vf ’
Sep | Oct | Nov.| Dee | an | Feb. | Mar.| Ape | May | Tune | Tuty | Qus |
Fic. 1.—Chart showing comparison of yearly range of evaporation in Spanish
oak-post oak forest (dotted line); short-leaved pine forest (heavy line); grazed beech
forest (broken line).
about the same minimum. The actual minimum was 7.39 Cc.
in late December, and the actual maximum 27.97 cc. in early May.
This forest, therefore, does not show such wide variation for the
seasons as do the others given, and the curve representing the
years’ averages runs more evenly for this forest than does that of
any other except the flatwoods. This evenness may be related
to the fact that, although the trees are deciduous, their leaves,
after dying and turning brown, remain on the branches most of
326 BOTANICAL GAZETTE [ocTOBER
the winter; and as they are coriaceous in texture and more or
less coated with felt on the under surface, they remain intact until
the time for the new foliage. The low summer rate (as compared,
for example, with the long-leaved pine rate) also may have a
relation to the fact that. although there is an absence of shrubs
or undergrowth of importance, these trees are dwarfed or scrub-
like, and the foliage grows low on the trunks; when growing
closely they make a thicket-like forest.
Seb. | Oct | Mov.| Dec | Jan.| Feb.| Mar-| Abr. | May |Tune | July | Qug
‘ad aa '
2 IN oS : ee |? £ \ F. \ .
wp7ai~ . ER OR / Ne Ps!
Fic. 2.—Chart showing comparison of average yearly rates of evaporation in
scrub oak forest (heavy line); flatwoods (broken line); long-leaved pines on dry lan
(dotted line).
Station no. 6, in the dry pine wood, gave the average evaporation
per day of 17.9 cc.; 12.28 cc. for the period January to May;
18.25 cc. for the summer period; 19.2 cc. for the winter period;
with minimum monthly average of 8.9 cc. in December and a
maximum of 32.5 cc.in April. The actual minimum was 4.15 CC.
and the maximum 56.19 cc., showing the widest range of any
station (fig. 2).
1917] GANO & MCNEILL—EVAPORATION RECORDS 327
The flatwoods station, on Leon Sand, gave an average for 18
months (with a break in the record for December and January .
1912-1913) of 12.99 cc. per day. The January to April average
for 1913 is not complete, but for the summer and winter periods the
averages are, in order, 13.24 cc. and 11.17 cc. The minimum
month is January, 5.94 cc. per day; the maximum in May is
19.8 cc. per day. The actual minimum falls lower than that of
any othér, being 3.88 cc. in February, and the maximum was
25.44 cc. in May.
The meadow stations were not in operation for a long enough
time to give results covering a year. From October to June the
willows averaged 12.47 cc. daily, comparable to the flatwoods
station. The average for the birch station for the time was 13.98
cc. daily. Their minima occurred in January and maxima in May.
Arranging the stations in the order of their yearly averages of
evaporation, beginning with that having least evaporation, their
order is as follows: hammock climax forest, willow (meadow) zone,
flatwoods, birch (meadow) zone, Spanish oak-post oak forest,
short-leaved pine forest, scrub oak forest, beech wood (open and
grazed), long-leaved pine forest. Omitting the meadow stations,
the others arranged in order of increasing rates are (for the summer
period June to November), after the hammock forest, the Spanish
oak-post oak forest, the flatwoods, the beech (grazed), the short-
leaved pines, the scrub oaks, and long-leaved pines. The order,
by winter average rates, is flatwoods, short-leaved pines, scrub
oaks, Spanish oak-post oak, beech (grazed), and long-leaved pines.
The order during the critical period of the year, from January to
May (a dry period and a time of sharply rising temperature, cor-
responding to the time of vernation of the deciduous trees and o
changes of leaves, in part or altogether, of many evergreens), is as
follows: mesophytic hammock forest, Spanish oak-post oak forest,
beech wood (grazed), short-leaved pine wood, long-leaved pine
wood, and scrub oaks. Of these the order of the forests on the
clayey soils of the upland is essentially that observed for their
succession, the difference in winter being in the place of the leafless
Spanish oak-post oak forest as compared with the conifer forest.
In the pine and oak forests on the dry sandy soils, the same relation
328 BOTANICAL GAZETTE [ocroBER
Sep Oct | Nerv| Dee Jan| Feb | Mar | Abr| Mey| June | Jere | Cel.
nS LAY Y Lis \.
je Sipe cs us
NG Wan AVA oe aes
Fic. 3.—Chart showing evaporation rates of 3 pine forests: long-leaved pine on
dry sand (heavy line); long-leaved pine on wet sand (broken line); short-leaved pine
(light line).
Sep.| Oct | Nov. | Dec.| Jan.| Feb.| Mar | Afbr.| May| Tane| Tuly Gug.
. ;
es fo te
Nb = :
4.—Chart showing comparison of evaporation rates, during same year, in
the 2 dott rom scrub oaks (heavy line); Spanish oak-post oak forest (light line).
1917] GANO & MCNEILL—EVAPORATION RECORDS 329
holds, the oaks showing a higher winter rate than the pines. The
two pine forests (short-leaved and long-leaved) on dry soil are
nearest together in their evaporation rates during the spring. A
comparison of the three pine associations and the two oak asso-
Ciations as charted will show these relations (figs. 3, 4).
The Leon Sand forest is singular in that it is so directly related
to the soil moisture, and although all other factors tend to make
the evaporation excessive, the constant humidity near the soil
surface of the ground, owing to the soil saturation, modifies the
curve until it is the most equable of any of those described in this
report.
Ricumonp, Inp.
FATS FROM RHUS LAURINA AND RHUS DIVERSILOBA!
JAMES B. McNAIR
(WITH ONE FIGURE)
STEVENS (12) has noticed that the green fruit of Rhus radicans
is very poisonous. STEVENS and WARREN (13), when investigating
the fruit of R. vernix, found the green fruit highly toxic, while the
ripe fruit is harmless. WARREN (15) attributes this interesting
change in toxicity to an apparent replacement of acrid resins by
wholesome and palatable fats. Besides these species of Rhus, a
fat (Japan wax) has been found in 4 species of Rhus: R. succedanea
.. R. acuminata DC., R. vernicifera DC., and R. sylvestris Sieb. and
Zucc. (6). All 6 of these species are poisonous, and it is interesting
to note that the discovery of fat in the fully matured fruit of Rhus
laurina Nutt. may add a non-poisonous species to the list.
Investigations were begun by me on the fats from Rhus laurina
Nutt. and R. diversiloba T. and G. with two objects in view: (1) to
discover whether or not these fats are identical with Japan wax,
and (2) to determine, if possible, the connection between this fat
and the poisonous property of R. diversiloba. This latter problem
appeared all the more interesting when the fact became apparent
that during the ripening of the drupes their poisonous properties
simultaneously decreased with their increase in fat. When the
fruits have reached full maturity (when the semi-transparent
epidermis loosens and easily falls off from the waxy mesocarp)
they are non-toxic. The toxicity was tested by thoroughly rubbing
the pulverized fruits, as well as an alcoholic solution from them
(concentrated to one-third of the original volume of the fruits), on
the skin of a sensitive person.
The fats experimented with were obtained by boiling the ripe
fruits in 95 per cent alcohol under a reflux condenser. The fat
samples were purified by repeated solution, evaporation of the
«Contribution from the Rudolph Spreckel’s Physiological Laboratory of the
University of California.
Botanical Gazette, vol. 64] [33°
1917] McCNAIR—FATS FROM RHUS 331
solvent, and crystallization of the solid matter. The substances
thus purified are pale yellow, hard, with a conchoidal and some-
what lustrous fracture. Their odor recalls that of tallow and
beeswax. Under the microscope they appear to consist of small
and large refractive grains. They are insoluble in water, slightly
soluble in cold 95 per cent alcohol and ether, easily soluble in hot
95 per cent alcohol (separate on cooling to granular crystalline
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan.
iG. t
mass), warm ether, benzol, petroleum ether, and carbon bisul-
phide. They form grease spots when melted on filter paper.
That glycerol is probably a constituent is evident from an irritating
odor of acrolein evolved when the substances are mixed with
powdered potassium bisulphate and heated in a dry test tube.
From a consideration of their physical and chemical properties
so far determined, the fats from R. laurina and R. diversiloba seem
to be similar to Japan wax. This means that similar fats have
been found in a non-poisonous and a poisonous species of Rhus.
332 BOTANICAL GAZETTE [OCTOBER
The wide variance in the physical and chemical constants of
Japan wax obtained by different experiments, and different experi-
ments by the same investigators, may have been due to several
- factors, namely, adulterations of water, starch, oil of Perilla oci-
TABLE I
ANALYTICAL FIGURES OBTAINED
R. diversiloba R. laurina
sce a al Bites 18°5C 0.8987 18°5C
° 13
Gas i BES aes 79 per cent (Hiibl.) | 11.44 per cent (Hiibl.)
.| 220.6 iy A
elting point....| 53° C. eC,
*Mg. sipbged ect per cent alcohol at 20° C.
t Mg. KOH per gm
moides Linn. (BRANNT 2), tallow (BRANNT), the fact that the
fat becomes transparent below its fusing point (18-23.5° F. below
m.p., BRANNT), the fact that the melting point becomes higher
with the age of the sample (BRANNT), impurities, and different
methods of analysis.
Morphology of fruit of R. diversiloba in relation to fat formation
The ripe fruit of R. diversiloba is oval, 5s-g mm. broad, 4-6 mm.
high, and 4-6 mm. thick. When first formed it has a shining
grass-green color and smooth texture. When dry it becomes brown
and presents long dark stripes which previously were only slightly
indicated. The outer surface of these stripes is depressed because
of the collapsing of the large resin ducts which lie directly beneath
them. The outer layer of the fruit, which is a drupe, is something
over 1 mm. thick. In the horizontal cross-section 20-30 large
resin passages are present. , These form a single outer row com-
pletely around, which conforms with the general outline of the
drupe. Many smaller resin ducts are present, which alternate with
the wider ones to form a row next to the seed. The arrangement
on the top and bottom of the drupe is less regular. The epidermis
is bordered by 2 or 3 layers of strong sclerenchymatous cells.
Between these border layers and the resin passages lies the paren-
chymatous tissue whose cells for the most part. contain solid fat. In
1917] McCNAIR—FATS FROM RHUS 333
the ripe fruit the fat appears in the principal tissue of the mesocarp.
Fat is not found in the exocarp, the thin walls and the inner bound-
ary of the mesocarp, the sclerenchymatous cells, the cells of the
vascular bundles and their sheaths, and the parenchymatous
sheaths of the resin passages:
The presence of solid fat in the fruit cannot be detected before
July. At the beginning of August fat formation is nearly com-
pleted. The granulated layer of fat can be seen in the cell between
the membrane and the protoplasm. This layer makes the lumen
smaller, increases on the outside, and goes in between the already
formed fat. Its granular form changes to striated masses. Before
the formation of this fat in the fruit a progressive increase in the
starch content is noticeable. Starch forms partly in the chromato-
phores in the cell and partly in the cells. When the fruit cells are
rich in starch the cells contain besides only granular protoplasm and
nuclei. This starch gives a positive reaction with iodine. When
fat formation is near completion no starch can be detected in the
fruit. In fruits which have nearly completed their growth the
resin passages are everywhere constricted by the growth of paren-
chyma sheaths. From a consideration of these phenomena fat
is apparently formed from starch and not from the resin-like
poisonous sap.
This view does not seem untenable, for it has been proved that
in the storage foods of plants carbohydrates and fats are inter-
changeable, and in certain cases carbohydrates are entirely replaced
by fats. Starch is stored in potatoes and in the tubers of dahlia,
and cane-sugar is stored in beet root; the seeds of the two former
plants contain oil, while those of the beet are starchy. Although
the grains of most grasses contain starch, some instances are known
in which fatty oil is present instead (Phragmites communis, Koeleria
cristata, etc.). In the cotyledons of Impatiens Balsamina amyloid
is stored in the form of enormously thickened walls, while in other
species of Impatiens the tissue of the cotyledon is thin-walled and
oil is present instead of reserve cellulose.
The change of carbohydrates to fats in the seeds of plants
has been studied by Scumupt (11), LeCLerc pu SABLON (4),
and others. These investigators have shown clearly that as the
334 BOTANICAL GAZETTE caare
carbohydrates decrease in seeds the fatincreases. For instance, whee
almond seeds first begin to ripen, they are rich in carbohydrates
and poor in fats; when fully matured, however, they are poor in
carbohydrates and rich in fat. The seeds of Ricinus and Paeonta
are also typical cases. It seems as though the oil in the mature
Ricinus seed comes from glucose, while that of the Paeonia is formed
from starch. As it is possible for the plant to translocate fat as
such, provided it be an emulsion sufficiently fine, or in the form of
fatty acids and glycerine, it might appear to some that the fats in
seeds have not been formed in situ, but have been conveyed there
by the sap. It cannot be denied that translocation of fat may
occur to a certain extent; but it is a fact that fats will appear as
the carbohydrates disappear in immature seeds even when removed
from the parent plant. This fact, when considered with the facts
known regarding the formation of fats in vegetative organs under
the influence of cold, leads to the inevitable conclusion that fats
are formed at the expense of carbohydrates and that this trans-
formation may occur 7 situ.
Scumipt (11) and LECLERc pu SaBLon (4) have shown con-
clusively that during the germination of oily seeds a reversal of
this process takes place, carbohydrates being formed apparently
from fat.
The processes by which carbohydrates are changed to fat
are still unknown. As the carbohydrates do not contain such
complicated carbon chains as the fats, the formation of fat from
carbohydrates must consist of a synthesis, in which the CHOH
group is converted into CH.; hence a reduction must occur.
The formation of fat from ‘carbohydrates in the plant has its
parallel in the animal. The great influence of carbohydrates on
fat formation in the animal was observed and proved by LAWES and ©
GILBERT (5), Voir (14), Lummert (7), and many others by means
of a series of nutrition experiments with different animals, with
foods especially rich in carbohydrates, who have apparently proved
that a direct formation of fat from carbohydrates does actually
occur.
The fat of the poison oak fruit is not a reserve food supply for
use of the cotyledon; this is shown by morphology and sprouting.
1917} MCNAIR—FATS FROM RHUS 335
When the drupe is planted, the growing embryo does not utilize the
fat, as it remains unchanged. The fat, however, may be of service
to the seed as a protection against cold on account of its low power
for heat conduction, increasing its chance of dispersal by streams,
as it is far lighter than starch (specific gravity of starch 1.56,
fat 0.9872); as a protection from rain and humidity; as a pro-
tection from fungi (PFEFFER 9); and as an attraction to birds
and therefore a factor in seed dissemination. The ripe fruits
persist on the plant during the winter, long after the leaves have
fallen, some until May. Birds, therefore, can see them for.a long
distance. When eaten,,the fatty covering of the drupe only is
digested; the ejected seeds can still germinate. Mésrus (8) has
observed the fruits of R. vernicifera eaten by half-wild pigeons at
Frankfurt. REINECKE (10) has recorded the doves of Samoa as
eating the fruit of R. tahitensis. BARRows (1) speaks of the con-
sumption of the fruit of R. venenata and R. Toxicodendron by the
crow. After eating the fruits the crow rapidly digests the nutritious
pulp and ejects from the mouth (in less than 40 minutes after
eating) the seeds clean and devoid of pulp, together with the sand
swallowed to aid in digestion. Of these ejected seeds go per cent
germinated.
Bryant (3) has observed that the favorite food of the roadrunner
(Geococcyx californianus) during the winter season consists of the
fruit and seeds of R. integrifolia. Unlike many birds which turn
their attention to vegetable food during the winter season, the
roadrunner appears to discriminate as to the kind of seeds taken.
Of the stomachs examined, those of 26 (31.3 per cent) contained
the seeds or fruit of R. integrifolia, and 8.4 per cent of the food
taken by all the birds was made up of this element. The attention
of the roadrunner is apparently attracted to this vegetable food only
during the winter season, when insects, lizards, and other kinds
of food are least abundant.
Summary
1. Substances more similar to Japan wax than to any other fat
have been isolated from the ripe fruit of R. Jawrina and R. diversi-
-
336 BOTANICAL GAZETTE [OCTOBER
2. A decrease in the poisonous properties of the fruit of R. di-
versiloba occurs simultaneously with the increase in fat content.
3. The decrease in the poisonous properties in the ripening of
the fruit of R. diversiloba eventually results in the fruit becoming
non-toxic. This phenomenon is not necessarily due to a chemical
transformation of the poison into fat for: (a) subsequent to the
formation of fat the cells in which it is deposited become filled with
starch; (b) it is possible for the plant to transform starch into fat;
(c) fat is not formed in the parenchymatous sheaths of the resin
passages; (d) consequent upon the formation of fat, the resin
passages are everywhere constricted by the growth of parenchyma
sheaths; (e) a similar fat has been found in the fruit of a non-
poisonous species of Rhus.
I am indebted to Professor T. BRairsrFoRD ROBERTSON for
having placed the resources of his laboratory at my disposal during
this investigation.
PASADENA, CAL.
LITERATURE CITED
1. Barrows, W. B., The common crow of the United States. U.S. Dept.
Agric., Div. Ornith. and Mammal. Bull. no. 6:85-87. 1895.
2. BRANNT, W. F., Animal and vegetable fats and oils. London. 1896
(pp. 138-141). :
3. Bryant, H. C., Habits i food of the roadrunner of California. Univ.
Cal. Publ. Zool. 17:29
4. Du SaBion, LE Cane ak Rend. 117: 524. i 119:610. 1894;
123:1048. 1896; Rev. Gen. Bot. 7:145. aes 2 313-
5. Lawes and GirBert. Phil. Trans. part 2.
6. LewkowITcu, J., Chemical technology and abe of oils, fats, and waxes.
London. 1914 (vol. II, p. 650).
7. : Pfliiger’ s Archiv. 71:—.
8. Mézsrus, M..——. Ber. Deutsch. Bot. Gesells. 15:435. 1897-
9. PFEFFER, Mw, Physiology of plants, transl. by A. J. Ewart. Oxford.
1g00 (Pp. 4
10. Sakis ¥, Ber. Schles. Gesells. 73: part 2, 75.
tz. ScHmipT, ——. Flora 74:300. 1891.
12. STEVENS, A. B., Poison ivy fruit. Amer. Jour. Pharmacy 80:93- 1908.
13. STEVENS, A. B., and WARREN, L. E., Poison sumac. Amer. Jour. Phar-
macy 79:499. 1907.
14. Voir, ——, Respiration. Sitzungsb. Miinch. Akad. 15:51. 1895-
15. WaRREN, L. E., ——. Pharm. Jour. 1909.
CURRENT LITERATURE
NOTES FOR STUDENTS
Crown gall.—Recent developments in the study of crown gall and its rela-
tion to animal cancer have been presented by Smira in several papers. The
first? of these, in point of completion although not in time of publication, is a
succinct account of remarkable growth phenomena resulting from the action
of Bacterium tumefaciens when inoculated into special tissues of plants. Four
cases are Sistngnshet
1. Whent dal cambium is inoculated, this tissue loses its tendency
to form mature structures having definite orientation. Instead, the cells
continue to divide rapidly, forming large masses of mostly embryonic par-
enchyma within which scattered and irregularly arranged xylem and phloem
elements are differentiated. The process recalls that described by Lamar-
LIERE? in the galls of Gymnosporangium and aptly designated by him as
“parenchymatization.”
2. When the cortical parenchyma is infected, a somewhat similar develop-
ment takes place. The cell divisions succeed each other so rapidly that the
cells in the proliferating tissue remain small in comparison with the normal
parenchyma, and appear to remain continually in an embryonic state. In
time, however, there is a tendency to develop vascular elements, and these are
then arranged in a more or less well defined stele. The vascular system of such .
tumors has no connection with that of the stem, consequently the galls
die from imperfect nutrition and lack of water. The galls of these two t
exhibit no external differentiation. They include all the forms of crown gall
described in former papers.
3. A more remarkable condition is brought about when the crown gall
organism is inoculated into the leaf axils of young growing plants (species of
Pelargonium, Nicotiana, Lycopersicum, Citrus, and Ricinus). The tumors
ae | 1 P nape vei Asem +,
t SMirH, Erwin F., Crown gall
a changed stimulus. Jolie: Agric. Research 6: ae pls. 18-23. 1916; see also
Le cancer est-il une maladie du regne végétal? Premier Congress Internat. Path.
Comp. Vol. II. 1912; Cancer in plants. Proc. 17th Internat. Souiies of Medicine.
Vol. III. Pathology. London. 1913; Further evidence as to the relation between
crown gall and cancer. . Nat. i i tha
crown gall of plants is cancer. Science 43:871-889. 1916; Chemically induced crown
galls. Proc. Nat. Acad. Sci. 3:312-314. 1917.
? Rey. Bor. Gaz, 427153. 1906.
3 Rev. Bor. Gaz. 52:75. I91I; 55:257- I913-
3
338 BOTANICAL GAZETTE [OCTOBER
thus produced are covered with abortive leafy shoots or with flower shoots if a
flower incept has been disturbed. On tobacco plants these teratoid tumors
may give rise to secondary tumots similar in nature. These daughter tumors
are connected with the parent growths by tumor strands which are quite
different in structure and location from those occurring in galls of the first
two classes. The tumor strands heretofore described were found in the Paris
daisy. They arise in the region of the primary xylem and consist of par-
enchyma tissue. The new tumor strand found in the tobacco occurs in the
cortex. It consists of a concentric bundle with the xylem surrounded by the
phloem. The daughter tumors arise at mocha along the strand and often
have all i Aue mics of the parent tum
st case, even more remarkable, ca when the young leaves of
tobance foie are infected with the crown gall organism. From such infec-
tions on the midrib and lateral veins tumors arise which produce leafy shoots.
These tumors the author regards as akin to teratoid tumors in animals. The
fact of their development is another proof that any plant cell not fully matured
may retain the capacity for developing the whole organism
n another paper,‘ written for medical readers, the salsioet of crown gall
is discussed in its relation to the problems of human cancer. The general
resemblances in mode of growth, cell multiplication, occurrence of tumor
strands, and production of secondary tumors in the two classes of growths are
pointed out. The materials presented in this paper are essentially those of
earlier papers, together with the new facts of the paper reviewed above. The
phenomena, however, are described in greater detail, and considered boa special
reference to their bearing on animal pathology. Here, as in other cases, the
author relies mostly on numerous excellent photographs for the vheacuratien
of his evidence.
n explaining his standpoint with reference to the bearing of his work on
the problems of animal cancer, the author makes no claim that the causal
organism of the crown gall has any relation to human cancer. It is pointed out,
however, that this organism induces in plants a set of phenomena which have a
st g parallel in the manifestations of animal cancer. Such phenomena are
the growth without function shown by gall tissue, the persistently embryonic
character of the proliferating cells, the lack of orderly differentiation of the
tumor tissues, the existence of tumor strands giving rise to daughter tumors
repeating the structure of the parent gall, and the occurrence of galls resembling
embryonic teratoids. It is further pointed out that in the crown gall the cell,
although apparently possessing invasive capacity, is not itself the parasite, as
4SmitH, Erwin F., Studies on the crown gall of plants; its relation to human
cancer. Jour. Cancer Reseuich 1:231-258. pls. 1-25. 1916.
sIt appears that the embryonic tissue of the gall to a certain extent pushes in
among the cells of the sound tissue, a phenomenon which distinguishes this gro wth
from other plant galls induced by fungous 0 ranimal parasites. The mode of progress
1917] CURRENT LITERATURE 339
JENSEN thought. On the contrary, the behavior of the cell is due to an invading
specific microorganism. These facts, together with the observation that in
one case at least (Rous’ sarcoma of fowls) the abnormal growth can be produced
by some sort of material separable from the cells and capable of multiplying
when injected into other tissues, are regarded by the author as greatly advan-
cing the contention that animal cancer is due to an intracellular parasite.
ey anterenting results® were obtained in a series of experiments
designed to f tumor growth in crown gall.
In this investigation the author was guided by the hypothesis that the sub-
stances produced in the metabolism of Bacterium tumefaciens must be the
direct cause of the cell proliferations. To the end of determining the effects
of such substances various plants were injected first with compounds which
chemical studies had shown to be products of the causal organism, and finally
with a large number of other substances.
The first experiments were conducted with ammonia, which in various
concentrations was injected into the stem cavity of Ricinus and into the fruit
cavities of young green tomatoes. The result of these injections was an abun-
dant formation of cushion-like intumescences within the cavities in both cases.
Later, proliferations of the same type were obtained by the injection of a large
number of other substances, including ammonium salts of organic and of
inorganic acids, dilute solutions of the acids themselves, salts, glucose, and
Saccharose, and in some instances to a slight extent with distilled water. In
many cases when the tissues of the pith cavities of Ricinus were exposed to
weak ammonia vapors from dilute solutions of ammonium phosphate or
ammonium carbonate in tubes sealed into the hollow stems, proliferations were
produced not only in the cavities the reagents but also in many inter-
nodes above and below the opened one. The action in these cases, therefore,
took place at a distance through thick partitions. The most striking result
was obtained from the injection of a 5 per cent solution of ammonium dihy-
drogen phosphate into a very young internode of Ricinus. In this instance the
pith cavity became completely filled by the proliferating pith, and from this
tissue a complete vascular cylinder was differentiated. The orientation of
the new inner cylinder was the inverse of that of the normal cylinder, the
phloem being at the center and the xylem occupying the outer region. Such
a complete cylinder was observed only once, but in many instances isolated
of the tumor strand through the tissues is not yet clear. Whether this structure
pushes its way through the pith or cortex by apical growth after the manner of the
internal roots of lycopods, or whether progress through the tissues is accomplished
by successive cell-invasion by the bacteria and subsequent differentiation of the in-
vaded cells into the characteristic tumor strand, has not yet been determined. From
eek of his stained sections Samir thinks that both types of invasion occur.
Erwin F., Mechanism of tumor growth in crown gall. Jour. Agric.
mis 8:165-186. pls. 4-65. 1917.
349 BOTANICAL GAZETTE [OCTOBER
concentric bundles were produced in the proliferating pith. In these the
phloem was always at the center of the bundle. Such bundles, the author
points out, occur normally in the axes of the inflorescence of Ricinus and in the
nodes. Superficial intumescences similar to those reported by VON SCHRENK’
were produced on cauliflower by exposure of the plants to vapors of ammonia
and of acetic acid mixed with alcohol.
e outgrowths here described all partake of the nature of intumescences
frequently observed in plants. In some cases, indeed, as in the instance de-
scribed of the complete filling of the pith cavity and the subsequent differentia-
tion of a vascular ring, the outgrowth is excessive. This behavior leads the
author to the belief that if the stimulus could be continually applied, one would
have a condition resulting in the production of tissue masses not unlike those of
crown galls. Since in his experiments the outgrowths also resulted from the
presence of many substances not the product of parasites, the author is inclined
not to attribute the effect to the specific chemical action of any compound, but
seeks for an explanation in some property common to all the compounds regard-
less of chemical composition. Such a common characteristic he finds in their
osmotic action, to which, rather than to chemical sana gatecrey he — their
effect. In this ection it is of interest to recall
produced by Arxrinson,? Miss Douctas,? and STEINER” by ahi plants
to conditions increasing water absorption and diminishing transpiration; and
by Soraver, KiisteR, von ScHRENK, and others as a result of application of
solutions. In the author’s own work the intumescences were mostly the result
of injection of solutions, but in some instances they resulted from the injection
of water. It is improbable that the osmotic disturbances induced by the appli-
cation or injection of water are the same as those effected by the application
or injection of solutions. The fact that the various disturbances produce
responses differing only in degree would seem to indicate that the causes deter-
mining the formation of intumescences have not yet been fully analyzed into
their separate factors. It is not unlikely that different plants react differently
in this respect. The experiments of STEINER would seem to indicate that such a
possibility exists —H. HassELBRING.
Taxonomic notes.—GarTeEs" has attacked the genus Polygonatum, which
he says “‘has been in a very chaotic condition owing to the lumping of species,
the transference of names, and the confusion of North American with European
7 Rev. Bor. Gaz. 40:390. 1905.
® Arxinson, G. F., Oedema of the tomato, Cornell Univ. Agric. Exp. Sta. Bull.
53:77-108. 1893.
9 DouGLAS, igh G. E., The formation of intumescences on the potato. Bot.
1907.
10 Rev. fem Get 402391. 1905.
. -™%Gares, R. R., A revision of the —_ web a een in North America. Bull.
Torr. Bot. Club 44: 117-126. pls. 4-6.
1917] CURRENT LITERATURE 341
species.” He recognizes 9 North American species, giving under each the full
synonymy and citations of exsiccatae. The amount of change is indicated by
the fact that the revision includes a new species combination, a new variety,
and 3 new variety combinations.
Komwzumr” has published some studies of the plants of oriental Asia,
Sessibiee new species and varieties. Notable among the genera is Morus, of
which 25 species are enumerated, 4 of which are new.
MooreE,* in connection with descriptions of numerous new species of
African Compositae, has established a new genus (Paurolepis) belonging to the
Vernonieae.
NAKAI,™ in continuing his studies of the flora of Japan and Korea, has
described 21 new species, mostly in genera familiar in this country. The
completed studies will furnish much additional evidence of the close relation-
‘ship of the Japanese and North American floras.
Payson, in studying the American perennial scapose species of Draba,
recognizes 26 species, 14 of which are described as new. The new species are
from Utah, Nevada, California, Oregon, Idaho, and adjacent Canada.
Povau,” in concluding his studies of Mucor, has presented a taxonomic
description of the 18 species investigated. In view of the fact that his experi-
mental work showed that the species of Mucor are usually plastic organisms,
varying especially with the substratum, it seemed desirable to attempt a
standardization of cultural requirements, by investigating as many species as
possible under the same cultural conditions. The 18 species described were
studied from uniform, standard bread cultures, and 6 of them are describe
as new
Sir"? has described a new genus (Parasyringa) of Oleaceae from China.
TRANSEAU® has published a list of the algae of Michigan, based chiefly
upon collections made by him during the summer of 1915, in connection wi
the M pens se bea es —— by other collections. Since
number of years, the records
no work on
7 Komzumt1, ore Contributiones ad floram Asiae Orientalis. Bot. Mag.
Tokyo 31:31-41.
73 Moore, — LeM., Alabastra diversa. XXVII. Jour.- Botany 55:100-
106. pl. 547. 1917
™4 NaKal, TAKENOSHIN, Notulae ad plantas Japoniae et Koreae. a Bot.
Mag. Tokyo 31:97-112. 1917.
5 Payson, E. B., The perennial scapose Drabas of North America. Amer. Jour.
Bot. 4:253-267. 1917.
%6 Povan, ALFRED H. W., A critical study of certain species of Mucor. V. Taxo-
nomic. Bull. Torr. Bot. Club 44:287-312. pls. 17-20. 1917.
Suita, W. W., Note on Parasyringa, a new genus of Oleaceae. Trans. and
Proc. Bot. Soc. Edinburgh 27 1193-96. 1916.
* Transeav, E. N., The algae of Michigan. Ohio Jour. Sci. 17:217~232. 1917.
342 BOTANICAL GAZETTE: [OCTOBER
for species are for the most part new to thestate. The list includes 226 species,
and among them there is a new species of Oedogonium (O. americanum), and
new varieties of Vaucheria geminata and Oedogonium undulatum.
AN ALDERWERELT,” in continuing his studies of Malayan pteridophytes,
has described 27 new species of ferns, among them a new genus (Campylo-
gramma), 11 new species of Lycopodium, and 7 new species of Selaginella.—
j. M. Cc.
Direct reading potentiometers.—The electromotive force of the hydrogen
electrode bears a logarithmic relation to the normal hydrogen-ion concentration
H-+ of the solution. Where large numbers of determinations are concerned,
the calculation of the reaction of the solution in terms of normal acidity be-
comes laborious, An attempt to simplify the process was made by SORENSON,
who introduced the Ph values.* Since the Ph value is the negative logarithm
of the hydrogen-ion concentration, the relation existing between these numbers
and the usual method of expressing acidity in terms of normality is not always
clear.
Bovie” has devised a potentiometer which reads directly in terms of
hydrogen-ion concentration. In the original article a full discussion is given
of the method of operating the instrument, as well as we the CoS ERCLO® of
the dip electrode to be used in titrations. Thi the operator
to titrate a solution to a definite hydrogen-ion concentration and thus peat
the error due to misjudgment of the end point as found by the indicator method.
Another advantage of the instrument is that it makes it possible to titrate two
different acids in the same solution or to titrate successively the hydrogen ions
of polyvalent acids or acid salts. It also makes possible the titration of such
acids as boric acid, which give an end point on the alkaline side of the neutral
ae of distilled water. The author gives a number of other very useful
applications for the instrument. The apparatus is very well adapted for mak-
ing large numbers of determinations rapidly and with an accuracy sufficient
for ordinary purposes.
Using logarithmic resistances instead of the logarithmic scale, BARTELL”
has devised a similar apparatus, which avoids the sources of error in the BovIE
apparatus and gives a greater accuracy. It is not expected that this type of
potentiometer will replace the older forms which are adapted to reading very
small potentials.—R. B. Harvey.
9 Van ALDERWERELT, Capt. C. R. W. K., New or interesting Malayan ferns.
8 and 9. Bull. Jard. Bot. Buitenzorg nos. 23 and 24. pp. 27 and 8. pls. 4. 1916 and
IQI7-
2 Bovig, W. T., A direct reading segura for measuring and recording both
the actual and total reaction of solutions. Jour. Med. Research 33:297- 1915-
BarTELL, F. E., A direct a ionometer. Jour. Amer. Chem. Soc. 39:63°-
Igi7-
1917] CURRENT LITERATURE 343
Mottling in citrus leaves.—JENSEN™ has attempted to see whether there
is any relation between mottling of Citrus leaves and the supply of nutrient
salts necessary for chlorophyll formation. Such was thought possible since
the Office of Biophysical Investigations had found that mottling is inversely
proportional to the humus content of the soil, and that decomposing organic
matter increases the soluble salts in the soil:of the groves. The following
statements from h 'y indicate t Its of the investigation: ‘Judged
by a comparison of the average percentages of the inorganic elements deter-
mined in healthy Citrus leaves and in leaves in the medium stages of mottling,
the data obtained did not show that the initial mottling could be accounted for
by deficiency in the transfer of the iron, calcium, magnesium, and phosphoric
acid from the conducting system of the leaf stem and midrib to the mesophyll
tissue. On the other hand, sharply localized yellow areas in old orange
leaves contained less of these elements than the adjoining green areas (mostly
veins), but whether that relation obtained in the initial stage of mottling was
not determined. In very badly mottled Citrus leaves there was in general
an increase in the percentage of these elements in the conducting tissues, includ-
ing the leaf stems, indicating difficulty in their transfer to the inesophyil tissues
in very —— stages of mottling, probably because the leaf had become
functionless.
‘The process of mottling is seemingly very complex, involving as it likely
does an unusually rapid decomposition of chlorophyll and not merely a cessa-
tion in chlorophyll formation. This problem may yield to solution, if at all,
only after a many-sided attack. In some of the algae, however, loss of chloro-
phyil seems to be a direct result of shortage of nitrate supply. Work of this
this as a possibility in Citrus plants, as well as to indicate
the complex nature : of the process. —Wwm. CROCKER.
Monocotyledony.—WorsDELL® has criticized the reviewer’s view of mono-
cotyledony in a paper which “‘is an astonishing one.” In fact, we seem to be
mutually astonished, neither being able to understand the reasoning of the
other. The paper opens with an account of “an uncommon abnormality,”
which consists of a ‘forked coleoptile”’ in a corn seedling, and this phenomenon
is the excuse for the rest of the paper. It may be well to record that this
“forked coleoptile” is a very common phenomenon, as all know who have had
much to do with corn ‘Seedlings 1 ” nets eeitivarios.
The author h f zonation , which are
fundamental in this connection, and zonation is by no means a “s
phenomenon.” Zonation enables one to realize, for example, that a prominent,
# Jensen, C. A., Composition of Citrus leaves at various stages of mottling.
Jour. Agric. Research 9:157-166. 1917.
%3 WorspELL, W. C., The morphology of the monocotyledonous embryo and of
that of the grass in particular. Ann. Botany 30:509-524. figs. 10. 1916.
344 BOTANICAL GAZETTE [OCTOBER
projecting stem tip and a meristematic region that later develops such a tip
are of the same ontogenetic significance, and therefore that a cotyledonary
ring may be lateral even if the stem tip is not organized. The cells that are
to organize it later are still apical. It certainly also gives a aS and more
consistent interpretation of the grass embryo than to imagine a cotyledon
consisting of such distinct structures as scutellum, — and coleoptile,
distinct in origin as well as in position and appearance. The author disposes of
the dicotyledonous embryo of Agapanthus as meaning a RRR: char-
acter, from which we are to infer that he still maintains the view that the dicoty-
ledons have been derived from the monocotyledons. We had assumed that
this view was no longer under discussion.—J. M. C
Temperature and viability—WAcGONER™ finds that the resistance of
radish seeds to high temperature is inversely proportional to the initial water
content at the time of heating. At effective temperatures the water content
fell with duration of heating. Three different varieties studied showed similar
resistance. WAGGONER finds that much of the past work on resistance of
seeds to high temperatures lacks precision because the operators allowed the
water content to vary greatly during heating. They heated in water in open
dishes, in the oven, or in dry corked flasks. The water absorbed or given off
by radish seeds during heating as determined by the use of one or the other of
these methods goes far to determine their resistance to heat. GRroves*® has
taken care of this source of error by securing his seeds gas-tight in tubes just
large enough to hold the roo seeds, thus leading to a rapid rise of vapor pres-
sure with heating and an equilibrium between the vapor of the air and the
water content without measurable water loss. It is interesting to see that
radish seeds can be dried down to 0.4 per cent moisture without injury, for
EwartT® has concluded that the sorts of seeds that are most resistant to drying
cannot withstand a moisture reduction below 2 or 3 per cent without injury;
while seat —_ and Populus will not withstand any drying in a desiccator.—
Wm. Cro
Organic nutrition of plants.—KNupson” has investigated the influence of
certain mono- and disaccharides, added to nutrient media, on the growth of
various green plants, as corn, peas, radish, vetch, etc. These plants can absorb
through the root system and utilize sugars in growth. The order of the sugars
with reference to beneficial effects varied with the kind of plant. Thus with
corn grown in the light, the order was glucose and fructose, saccharose, maltose;
Wacconer, H. D., The viability of radish seeds (Raphanus sativus L.) as effected
by high temperatures and water. Amer. Jour. Bot. 4:299-313. fig. I- 1917-
*s Bor. Gaz. 58:169-189. 1917.
% Ewart, Proceedings and Trans. of the Liverpool Biol. Soc. 10:185-193- 1896.
*1 Knupson, Lewis, Influence of certain carbohydrates on green plants. Cornell
Agric. Exp. Sta. Mem. 9:1-75. 1916.
1917] CURRENT LITERATURE 345
while with Canada field peas it was saccharose, glucose, maltose. lactose.
Timothy was found to utilize lactose when grown in darkness, but not when
grown in light. The influence of the sugars upon the rate of respiration in the
vetch was observed, with the result that saccharose, glucose, and maltose
accelerate respiration very noticeably, the latter somewhat less than the other
two. Galactose was found to be toxic to wheat, peas, corn, and vetch, even at
low concentrations; while glucose antagonizes the toxicity of galactose, possibly
by rendering the roots impermeable to galactose, or by altering galactose
metabolism in such a way as to prevent formation of toxic oxidation products.
The author suggests as a general conclusion that soluble organic substances
produced from humus during decay may play a more important rdle in the
organic nutrition of plants than we have hitherto thought.—CuArLEs A. SHULL.
Osmotic pressure in parasite and host.—Using the cryoscopic method,
Harris and LAawrENcE® have studied the osmotic relations between 7 species
of Jamaican mistletoes and their 19 hosts. They that the sap concentra-
tion of the chlorophyllous tissues of the parasite is nearly always higher than
that of the mature leaves of the host, the parasites showing an average con-
pressure. This relationship is not a nec one, however, for in several
cases the parasites possessed sap of a lower concentration than their hosts.
In such cases it is assumed that the host supplies more than sufficient water to
meet its own needs, so that the parasite is not in direct competition with the
leaves of the host, but merely secures water from the same transpiration stream.
In cases of secondary parasitism, the osmotic pressure increases from host to
primary and from primary to secondary parasite. The sap from the stems
of leafless species of Dendrophthora possesses a lower concentration than that
from leaves of species of Phoradendron and Phthirusa. The meaning of this
is not discussed. It may involve differences in the rate of photosynthetic
activity in the leafless and leafy forms.—CHARLES A. SHULL.
Galls.—Essic” calls attention to the introduction of the chrysanthemum
gall fly from Europe. This pest was not known in the United States previous
to 1915. It causes cone-shaped galls which often distort the shoot beyond
recognition, and eventually causes death of the infected parts. It sometimes
destroys one-third of the crop.
WELIs* gives us a very important study o the galls of the blackberry
The purpose of the paper is threefold: (1) a study of the histology of the galls;
8 Harris, J. ARTHUR, and LAWRENCE, JouN V., On the osmotic pressure of the
Kage — of Jamaican Loranthaceae parasitic on various hosts. Amer. Jour. Bot.
3:438-455. 1916.
> ieee E. O., The chrysanthemum gall fly, Diarthronomyia hypogaea F. Low.
Jour. Econ. Ent. 9:461-468. 1916.
%* WeLts, Bertram W., The comparative morphology of the zoocecidia of Celtis
occidentalis. Ohio Jour. Science 16:249-290. pls. 8. 1916.
346 BOTANICAL GAZETTE [OCTOBER
(2) a study of the galls of Celtis occidentalis; (3) a comparative study of struc-
tures. The work is exceptionally well done and well presented. There are
kn pe
lepidopterous galls are kataplasma in character, and the hemipterous and
dipterous galls protoplasma in character. This latter type is more closely
comparable to the normal plant parts, but the tissue forms are new. e
author very properly suggests that zoocecidology presents a unique field for
the study of problems pertaining to the mechanism used in the expression of
hereditary characters.—MEL. T. Coox.
Germination of rice.—Nacar has made rather an extensive general study
of the germination of rice, touching many points that have previously been
worked out on other seeds. The cutinized inner integument of the ripe fruit
is a semipermeable membrane. Such membranes have been found in the fruit
walls of many grasses and in the coats of many seeds. Desiccated seeds of
rice are not injured by steeping for 24 hours in ether, chloroform, absolute
alcohol, acetone, and other substances. This is in accord with the work of
BEQUEREL and of SHULL,33 who have found that the dry coats of many seeds
are impervious . such substances, but that, as the water content of the coats
rises, they become more pervious. Rice germinates in an extremely low partial
pressure of oxygen, yet the germination is abnormal, the hypocotyl growing
only under considerable oxygen pressure. Acids and bases show no stimulative
effects upon the germination of rice. A few hours of exposure to liquid air
does not injure the seeds of rice or buckwheat. Two hours’ exposure to 97-
° C. kills Zea Mays, but does little injury to rice, especially if it is desic-
cated.—Wm. CROCKER.
Alkalies and salt absorption.—As a phase in the analysis of the tees of
alkalies upon the development of plants, BREAZEALE* has studied the effect
of NaCl, Na.SO, and Na,CO; upon the absorption of nitrates, phosphates, and
potash by wheat seedlings. Up to 1000 ppm. in a nutrient solution they do
not affect the absorption of nitrates. In this concentration NaCl does not
modify phosphate absorption, but slightly depresses potash absorption. In
1000 ppm., NazSO, depresses the absorption of potash and phosphoric =
to approximately 70 per cent of that of the checks. In equal mol co
Na,CO; depresses the absorption of potash to 20 per cent and phosphoric er
to 30 per cent normal. With Na,SO, these depressing effects were evident in
300 ppm. The writer thinks the depressing effect of the Na2SO, is due to its
3t NAGAI, vagrant Some studies on the germination of seeds of Oryza sativa.
Jour. Coll. Agric., Imperial University Tokyo 3:109-155. 1916.
® Bor, Gaz. 56:169-199. 1913; 63:373-397. 1917.
33 Bot. GAZ. 56: 169-199. 19
REAZEALE, J. F., Effect os al salts in water cultures on the absorption
of plant food wheat seedlings. Jour. Agric. Research 7:407-416. 1916.
1917] CURRENT LITERATURE 347
reaction with CaCO; of the substratum, thus forming Na,zCO;. Extensive
studies of this sort can add much to our knowledge of the absorption of salts
by plants and intereffects of salts upon each other as regards absorption.—
Wm. CROCKE
Calcium compounds of the soil.—Under this titles E. C. Saorrey, W. H.
Fry, and W. Hazen, members of the Bureau of Soils, have analyzed 63 soil
samples of 23 types from 24 locations of 19 states. They have calculated the
percentage of calcium combined with humus compound, calcium carbonate,
calcium sulphate, and calcium as difficultly and easily decomposed silicates.
They find a wide variation in total calcium content and in calcium carbonate
and the two classes of silicates, and there was no constant relation between the
total calcium content and the percentage of any of the calcium compounds.
Calcium combined with humus compounds was absent in 29 soils. type
which is recognized as a good alfalfa soil is characterized by high calcium
content, but low content of calcium carbonate. This indicates, as does other
evidence, that alfalfa requires a rather high content of calcium ion as a nutrient
or balancer of the soil solution, rather than merely calcium carbonate as a
neutralizer of acidity —-WM. CROCKER.
Phylogeny of ferns. —Bower,® in continuation of his phylogenetic studies
of the ferns, has developed some obs iie conclusions in reference to what
he calls the “‘acrostichoid condition,” meaning the spreading of exposed
sporangia “uniformly over a considerable area of the sporophyll.” This fact
was the basis of the old genus Acrostichum, which Bower has come to regard
not as a natural genus, but as a state or condition which may have been attained
along a number of phyletic lines. In the present paper he has presented a
number of genera which he regards as “‘dipterid derivatives,” that is, derived
from a phyletic stock characterized by Dipteris, which show various stages of
advance toward the acrostichoid condition. According to this view, a number
of so-called genera of ferns are form genera, not being what Bower calls
“phyletic unities.”” The increasing evidence of parallelism in evolution is
raising the question of ~ Phyletic unity” in connection with all of our larger
genera.—J. M. C.
Pine forests of Virginia and the Carolinas.—Harper®” recently devised a
method for securing a rough quantitative analysis of vegetation from notes
taken at frequent intervals from the car window or while walking through the
country. He made such notes during 53 hours of railroad travel and 21 hours
35 Jour. Agric. Research 8:57-77. 1917.
Bo ., Studies in the phylogeny of the Filicales. VI. Ferns showing
the ““acrostichoid ” condition, with special reference to dipterid derivatives. Ann.
Botany 31:1-39. pls. 1, 2. figs. 15. =
37 Harper, R. M., and vegetation of northern Florida. Ann. Rep.
Fla. Geol. Survey 6:163-437. ro
348 BOTANICAL GAZETTE — [OCTOBER
- of walking in Virginia and the Carolinas. To obtain the relative abundance
of species in the area involved3* he counted the number of times each species
was mentioned in the notes, and multiplied the figures for Pinus Taeda and
P. palustris by 5, and for the other conifers by 3 before calculating the per-
centages. The figures for smaller trees were divided by 2 or by 10, for shrubs
by 100, and for herbs by 500. The results were tabulated and are rather
interesting. Some estimates of annual increment of the whole vegetation,
of the amount of mineral matter taken each year from the soil, and of the
amount of water transpired are based upon these analyses. —GrEo. D. FULLER.
Forest sanitation—In a recent bulletin MerrNecKE? emphasizes the
importance and also the difficulties of giving phytopathology a proper place
in forest regulation. He elaborates methods of investigation and application,
exemplifying by an actual study of Abies concolor. Forest sanitation is the
keynote of the remedial measures proposed, a system of forest regulation which
will give proper attention to the removal or destruction of diseased indi-
viduals from the community.
It is also interesting to note that Wetr,* after discussing the character
and nature of the injuries due to various mistletoes, outlines methods of forest
sanitation consisting of directing cutting so as to effect the removal of diseased ©
communities and individuals. Such methods of forest sanitation he believes
ill become increasingly practicable with the increasing demand for cutting
privileges in the National Forest Reserves —Gro. D. FULLER.
an sand dunes.—In a recent bulletin SaANForD® estimates that
weds dunes stretch for over 400 miles along shore lines of the state of Michigan
and cover not less than 550 square miles of its territory. In the southern
peninsula, with the removal of the forests, many of the dunes are becoming
active again and now constitute a menace to valuable fruit growing lands.
The importance of maintaining a forest cover is pointed out, and the various
recognized methods of dune reclamation are described. The failure of certain
efforts to control dune movement by planting is shown to be due to a dis-
continuance of work before the final cover of permanent forest growth becomes
established. Such plantings made by the government at Manistee in 1902
resulted in a temporary cover, which a small amount of subsequent planting
38 HarPER, R. M., A quantitative, ‘hse and dynamic study of the vegeta-
tion of the Pinus Taeda belt of Virginia and the Carolinas. Bull. Torr. Bot. Club
44° ite te
, E. P., Forest pathology in Soseks regulation. U.S. Dept. Agric.
Bull. me Pp. Fs 1916
EIR, J.R See suggestions on the control of mistletoe in the national forests
of pe pnerescas Forest Quart. 14:567-577. 1916:
4 SanrorpD, F. H., Michigan shifting sands: their control and better utilization.
Mich. Agric. Coll. Exp. Sta. Bull. 79. pp. 31. figs. 22. 1916.
1917] CURRENT LITERATURE 349
would have converted into a permanent forest. A neglect of this attention
resulted in the complete failure of the project.—Gro. D. FULLER.
Nitrogen relations of semi-arid soils —McBrtu® finds that semi-arid soils
fail to nitrify dried blood when it is added in 1 per cent quantities. Under the
conditions ammonia accumulates in the soil and 50 per cent of the nitrogen
may be lost to the air (probably as ammonia) within 6 weeks. When added at
ordinary fertilizer rates nitrification is complete. With green manures, espe-
cially legumes, nitrification is rapid. Fifty per cent of the nitrogen of the green
manure is transformed to nitrates in 30 days. Furrow irrigation leads to the
accumulation of the larger part of the nitrate in the surface 6 inches of the soil,
and this often results in niter spots. Overhead or basin irrigation gives far
better results. Mottled orange leaves show higher water content than checks,
and extreme mottling is often, yet not invariably, associated with high nitrate
content.—Wwa. CROCKER.
Effect of dust on photosynthesis.—The effect of surface films and dusts on
physiological processes in plants has aroused considerable interest in recent
years. California citrus vegetation in the neighborhood of cement works
this fact to determine the effect of dusts on rathohydrate synthesis. He found
that the cement dust in some cases shuts out as much as 80 per cent, of the light
- from the upper surface of the leaf, but this high exclusion of light did not
interfere with carbohydrate synthesis. This work bears out in a practical and
interesting way that of Brown and EscomseE in showing the small amount of
light that is really necessary for carbohydrate synthesis.—Cuas. O. APPLEMAN.
Nitrogen fixation—The question of nitrogen fixation by filamentous
fungi has been = thee smb by Duccar and Davis* with reference to Asper-
gillus niger, Macrosporium commune, Penicillium digitatum, P. expansum,
Glomerella Gossypii, and Phoma Betae. Of these, Phoma Betae was the only
form which was definitely shown to be capable of fixing free nitrogen. The
quantities fixed by this fungus varied from 3.022 to 7.752 mg. per culture of
5occ. of solution when sugar beet or mangel decoction with added sugar
were used as culture media. The authors give a critical review of all the
available literature on the subject, and in their own work exercised every pre-
caution to avoid the errors and faulty methods which have led to the numerous
conflicting results in the investigations of this problem.—H. HAssELBRING.
# McBeth, I. G., Relation of the transformation and distribution of soil nitrogen
to the nutrition of citrus plants. Jour. Agric. Research 9:183-252. figs. 19. 1917-
# Younc, H. D., Studies on the relation of cement dust to citrus vegetation.
I. The ack on photosynthesis. Biochem. Bull. 5:95~100. 1916.
“4 Duccar, B. M.; and Davis, A. R., Studies in the physiology of the fungi.
I. Nitrogen fixation. Ann. Mo. Bot. Gard, 3°413-437- 1916.
350 BOTANICAL GAZETTE [ocroBER
Himalayan vegetation—Among the matters of botanical interest
STEWART has emphasized is the absence of all luxuriant tropical vegeta-
tion from this part of India, the indigenous flora being rather of the desert
and scrub types. Perhaps the most interesting thing concerning this little
known region is the similarity of the forests on the north side of the
mountains to those of the eastern United a as shown by the abundance
of trees of such familiar genera as Pinus, a, Abies, Taxus, Juglans,
Betula, Ulmus, Prunus, Acer, Quercus, Populus, aa Berberis. Set in strong
contrast are the most abundant genera upon the corresponding southern
slopes. This aggregation includes Acacia, Capparis, Tamarix, Zizyphus,
Melia, Albizzia, and Olea.—Gro. D. FuLiEr.
corrhiza of Marattiaceae.—West® has made a careful study of the life
history, host relations, and systematic position of a fungus long known to be
present in the roots of the Marattiaceae. It is one of the Phycomycetes, and
most nearly approaches Phytophthora in such characters as are available, but
sexual organs were not observed. West has established a new genus
(Stgasporium to include it. No injury to the cells of infected roots by the
parasite could be recognized, and the resting spores, with their oily contents,
are also formed at the expense of the host. ‘‘The advantage of the association
is almost entirely on the side of the fungus, the host plant thriving in spite of
the presence of the endophyte.”’—J. M. C
Cambium in monocotyledons.—Mrs. ArBER‘ has brought together the
i oe Bate 2 red gin f£ 1 ele c Ld 1 hiwm
in monocotyledons, and records also some new observations. It is clear that
such a cambium occurs more widely among monocotyledons than has been
generally supposed. To the previously recorded cases she adds the inflores-
cence axes of Eremurus himalaicus and Nothoscordum fragrans, and the young
shoots of Asparagus officinalis. The widespread occurrence of this ‘vestigial,
intrafascicular cambium” is a strong additional argument in favor of the
derivation of monocotyledons from dicotyledons.—J. M. C.
Seedling anatomy of Ranales.—Miss BLAcKBURN*® has investigated the
seedling anatomy of a large number of the Ranales, chief attention being given
to the Ranunculaceae. The results of chief phylogenetic interest are the
43 STEWART, RALPH R. 93 observations on the flora of northwest Himalaya.
Torreya 15:21 gabe. Jigs. ‘
#® Wrst Cyrit On Meas Marattiacearum and the mycorrhiza of the
Marattiaceae. Ann. Botany 31:77-99. pl. 3. figs. 9. 1917-
47 ARBER, AGNES, On the occurrence of intrafascicular cambium in monocoty-
ledons. Ann. Botany 31:41-45. figs. 3. 1917.
# BLACKBURN, KaTHLeeN B., On the vascular anatomy of the young epicotyl
in some Ranalean forms. Ann. Botany 31:151-180. pl. 13. figs. 19. 1917-
s
1917] CURRENT LITERATURE 351
general prevalence of the trilacunar trace in the seedlings, and the almost
universal occurrence of a single ring of bundles connected at a very early age
by cambium. This interfascicular cambium is usually absent in the adult
stems of the ee anunculaceae, but it is invariably present at some
stage in the seedling. The evidence of the origin of herbs from woody plants
is increasing.—J. M. C
Germination of ascospores.—BRIERLY® has experimented with the ger-
mination of the ascospores of Onygena equina, a fungus occurring on decom-
posing horns and hoofs of cattle, sheep, etc. The results showed that “ripe”
ascospores will germinate directly after a prolonged resting period, and that
this period may be curtailed or eliminated by treating the spores with arti-
ficial gastric juice, but not by subjection to low temperatures. “The full-
grown unripe ascospores and the chlamydospores will germinate immediately
in the absence of digestive treatment.” —J. M. C
Respiration.—APPLEMAN® has investigated quantitatively the relation of
oxidases and catalase to the process of respiration in potatoes. He found that
there was no correlation between intensity of respiration and oxidase activity,
but that catalase activity of the extracted juice of the potato shows a close
correlation with the respiratory activity of the tuber. He considers, therefore,
that the oxidases are not the controlling factor in respiratory intensity, at
least in potato tubers, whatever réle they may have in connection with biologi-
cal oxidations.—Cuaries A. SHULL.
History of forest ecology.—In a rather extensive review of the literature
of botany and of forestry investigations, BOERKER* has attempted to trace the
influence of both upon the development of the new phase of science known as
forest ecology or silvics. Perhaps the most important part of the paper is-that
in which he traces the ecological principles which were stated by some of the
earlier leaders in forestry, but which have received little attention from their
fellow foresters. Of almost equal importance is the rather extensive bib-
liography.—Gero. D. FULLER.
Wandering tapetal nuclei—Prckerr® has described in detail the differ-
entiation of the tapetum and its subsequent behavior in Arisaema triphyllum
# Brrerty, Witi1am B., Spore germination in Omygena equina Willd. Ann.
Botany 31: ja ea 1917.
® AppLEMAN, CHARLES O., Relation of oxidases and catalase to respiration in
plants. Amer. Jour. Botany 3:223-233. 1916.
* Borrxer, R. H., A historical study of forest ecology; its development in the
fields of botany and forestry. Forestry Quarterly 14:380-432. 1916.
8 Pickett, F. L., The wandering tapetal nuclei of Arisaema. Amer. Jour. Bot.
3:461-469. pl. 20. figs. 8. 1916.
352 BOTANICAL GAZETTE [OCTOBER
and A. Dracontium. The tapetal cells early show peculiarities of cell wall,
cytoplasm, and nucleus. The wall entirely disappears, and the freed proto-
plasts form a “periplasm”’ that spreads through the cavity of the sporangium.
The forms assumed by the tapetal nuclei, as well as their peculiarities of struc-
ture Jesse the possibility of “active migration among the developing pollen
spores.”—J. M. C.
Vermont trees.—One of the most recent additions to the rather large
series of tree manuals is from Vermont. It closely resembles that from
Michigan previously reviewed,54 but it has been revised and modified to meet
the slightly different conditions in the new region. There are two sets of
keys, one for winter and another for summer use. These, together with the
illustrations, should make the identification of any tree an easy matter.—
Gro. D. FULLER.
Fossil Sequoia from Japan.—Miss Yasut has*s described a new species
of Sequoia (S. hondoensis) from a coal field of Japan belonging to the Tertiary.
The genus was recognized, not only by its normal structural features, but also
by characteristic wound reactions. This discovery adds to the evidence of the
wide distribution of Sequoia during the Tertiary, and also adds testimony to
e assertion that Sequoia has descended from the Pityoxylon type.—J. M C.
The vegetation of New York State—Brays has compiled a useful
description of the vegetation of New York State, seen from the viewpoint of
an ecologist. The state is divided into zones according to MERRIAM’s system,
a map showing the modifications of the zones resulting from differences in
altitude and the changes due to soil and to proximity to the Great Lakes is
produced. The various forest types are well described.—Gero. D. FULLER.
Anatomy of epiphytic orchids—Curtis*’ has published a detailed account
of the anatomy of 6 epiphytic orchids from New Zealand. Considerable varia-
tion is shown in the extent and distribution of the different tissues, and the
paper is full of data that will be useful when the anatomy of orchids comes to
be organized.—J. M. C.
ss Burns, G. P., and Oris, C. H., The trees of Vermont. Vt. Agric. Exp. Sta.
Bull. 194. oe 244. pls. 90. 1916.
54 Bot. Gaz. 57:77. 1914.
ss Yasut, Kono, A ~— wood of Sequoia from the Tertiary of Japan. Ann.
Botany 31: 101-106. fl. 4. 1917.
% Bray, W. L., The aan of the vegetation at jae York State. N.Y.
State Coll. Tema: Syracuse Univ. Publ. 3:pp. 186. figs. 52. 1915.
s7 Curtis, K. M., The anatomy of 6 -— species of the New Zealand
i Ann, Hoteny 31:133-149. pls. 7-12. 1917
VOLUME LXIV NUMBER 5
14k
BOTANICAL GAZETTE
NOVEMBER 1917
FOOTHILLS VEGETATION IN THE COLORADO
FRONT RANGE
CONTRIBUTION FROM THE HULL BOTANICAL LABORATORY 237
ARTHUR G. VESTAL
(WITH EIGHT FIGURES)
The coniferous forests of the Rocky Mountains are fairly well
known; the other plant associations have been little studied. In
the present account descriptions are given of typical representations
of the plant communities of the foothills zone. The area is confined
to the eastern slope of the Rockies in Colorado. By the foothills
zone is meant the lower elevations, from the plains at 5000-6000 ft.
to the middle slopes at 7500-8000 ft. The vegetation zones of the
Colorado mountains have been characterized by RAMALEY (10).
A large part of the field study has.been made in the area just west of
Boulder, during three years’ residence at the University of Colorado;
the other parts of the region have been studied on numerous visits,
chiefly to stations at or near the mountain-front, from the Big
Thompson River as far south as Raton, New Mexico. This
article is the second of a series dealing with the vegetation and plant
geography of the eastern mountain-front in Colorado. The first
account (24) is of the plains and prairie associations of the region.
The writer is indebted to Professor FRANCIS RAMALEY for many
kindnesses and for help in different ways.
Grassland in the Rocky Mountains has a much more important
réle than is usually accredited to it, particularly in the lower slopes.
353
354 BOTANICAL GAZETTE [NOVEMBER
It is perhaps the conspicuousness of the trees, especially in distant
views and in profiles of slopes (fig. 8), which gives the common but
not wholly true impression that the foothills are generally forested
with conifers. The rock pine, the most generally distributed conifer
of the region, forms relatively few and scattered true forests; it
usually grows in very open formation, in mixture with the grassland
which covers most of the surface. The general aspect of the vege-
tation is that of an open growth of grassland and scattered pines
over a dry and partly bare upland of granitic hills. Semi-meso-
phytic and phytic communities, of both herbaceous and woody
plants, occur; but only locally, in moister or more sheltered ravines
and canyon-bottoms. The vegetation complex of the mountain-
front is a modification of that of the foothills, but is less simple in’
composition.
Environmental conditions
The Front Range in Colorado is an up-arched and dissected
plateau of crystalline rocks, the tops of most of the hills forming the
remains of a peneplaned surface; scattered higher mountains
represent monadnocks surmounting the former general level. The
eastern part of the plateau slopes gently toward the plains, the
sedimentary strata of which are here upturned against the granitic
rocks, forming sloping crags on the outer face of the foothills, or
hogback ridges separated from the hills by north-south valleys.
The physical geography of the Front Range is described by DAvIS
(5). Itis with the lower, more easterly part of the granitic plateau
and with the more irregular country of the mountain-front that
this study has to do.
The climate of the foothill region is dry, though not enough so
to be called semi-arid, like that of the plains. Rainfall at the
mountain-front is from about 15 to 18 inches average for the year;
higher in the northern part of the state and onthe elevated Platte-
Arkansas divide, lower south of the Arkansas River. The upper
foothills receive about 18-20 inches. Annual variation of rainfall
is considerable. Most of the rain comes during the growing season.
At Boulder, and in the northern foothills generally, April and May
are the rainiest months; in the southern foothills the earlier part
of the summer is drier than later. This, with higher summer
».
BORD cs a? VESTAL—FOOTHILLS VEGETATION 355
temperatures and probably greater insolation, gives a drier aspect
to the southern foothills; pinyons are abundant, instead of rock
pine, as in the northern part of the state. Mean annual tempera-
tures in the foothills vary from 40 to 50° F.; mean summer tem-
peratures 60 to 70° (ROBBINS 17). Evaporating power of the air
is great, though much less than on the plains. Local variations
in atmospheric conditions, due to surface configuration, are con-
siderable. Insolation is much greater on summits and south-facing
slopes than on north-facing slopes or in ravines. The drying winds
are usually from the west, and their effects are greatest on summits
and the flatter uplands.
Local and topographic factors are extremely and very locally
variable. Position with reference to surroundings, and slope, its
amount and direction, may perhaps be called the two master
factors of the topographic complex. Slope and position are most
important in determining conditions of soil deposition or removal
(consequently depth and texture of the soil); conditions of absorp-
tion and run-off, drainage, or seepage from above, or possible
seepage from snowdrifts; presence or absence of plant remains,
which may contribute humus, or locally form a mulch (pine needles) ;
and conditions of exposure to sun and wind with its attendant
effects. The granitic hills in general (fig. 1) are in an early-mature
Stage of topographic development (for a mountain region of
resistant rocks); the side-slope profiles are nearly straight, with
comparatively little detritus covering the bottom of slopes; the
tops of the hills are usually rounded, and hardly more subject to
erosion than the sides. In general, the foothills are so well drained
that bogs, marshy flats, and moist-soil meadow areas are infrequent,
even in canyon-bottoms. Hilltops and side-slopes are covered,
usually thinly, with rock-débris or with decomposed granite soils,
varying in texture from coarse gravelly material of angular frag-
ments’ to fine black loamy humus. Wide dikes and occasional
outcrops of more resistant rock have only a little soil, in joints and
crevices, hardly any elsewhere.
* The writer has not been able to find a distinctive name for this coarse angular
débris resulting from decomposition of granite; it is not re & Os tone Ce word
usually implies; in this article it will be called “ te-gravel.”
356 BOTANICAL GAZETTE [NOVEMBER
Texture of soil in its influence on water relations is probably
the most important soil factor in the foothills, so far as local distribu-
tion of plants is concerned. Especially interesting are some of the
features of mixed soils, in which fragments of greatly different sizes
are intermingled. Rocks of all sizes may occur on the surface, or
buried among finer fragments as rock-débris of detrital slopes.
Where the large fragments are imbedded beneath the surface in
fine soil, the water content of the latter appears to be increased.
1,.—General view in foothills, looking westward to snowy range-crest; fore-
Fic
ground a eh slope; general vegetation grassland with scattered pines; southwest of
Boulder, 7200 ft.
Where the large rocks are exposed at the surface, moisture condi-
tions appear to be more favorable immediately beside and under
them, so that comparatively mesophytic plants are seen growing
in mixture with xerophytes, the former always growing beside or
from under the surface rocks. This effect will be noticed in the
lists of species; many plants are found in both xerophytic and
mesophytic assemblages.
The more frequently recurring combinations of topographic and
atmospheric factors which form effectively different local environ-
ments for plants may be viewed in the synopsis which follows. It
is intended to apply only to the foothills proper; a number ol
situations of the mountain-front belt cannot be included herein.
1917] VESTAL—FOOTHILLS VEGETATION . 357
CLASSIFICATION OF FOOTHILLS HABITATS
Xerophytic neg (the general condition of summits and side-slopes)
Rocky habita
Craggy pe and rock-walls (see figs. 2, 3)
Rock-strewn detritus slopes
Rock-talus, usually less stable than preceding
“Granite-gravel” habitats
Compacted granite-gravel floors and side-slopes (see fig. 3)
Loose granite-gravel floors, washes, and talus (= gravel slides)
Fine-soil habitats
ed-soil floors and detritus-slopes (fine soil with imbedded and superficial
rock fragments of various sizes)
Fine-soil floors and detritus-slopes (infrequent)
Less xerophytic habitats (valleys and steep slopes, etc., relatively local)
Less xerophytic side-slopes coined? north-facing, cantly of considerable
gradient, and best developed in valleys)
Mesophytic ravine habitats
Narrow ravines (best developed in small side-canyons, especially on the
south side of eastward-flowing main streams)
Canyon-bottoms (the wider bottoms of the larger canyons are sometimes,
however, exposed and xerophytic)
Seepage and dripping areas (infrequent and small)
Stream-side habitats (with usually constant supply of soil moisture, but
widely varying atmospheric conditions
Synopsis of plant associations
The following synopsis is aimed to give in perspective the
distinguishing characters of the plant communities of the foothill
region. It is based upon whatever features of the particular com-
munity seem most distinctive and appropriate: growth-form,
moisture relations, physiographic, geographic, and successional
relations.
CLASSIFICATION OF FOOTHILLS ASSOCIATIONS
iations generally primitive in character: the first vegetation of new or
adivoubic & habitats, usually in rocky or gravelly situations; vegetation
open and sparse, generally xerophytic
Plants lichens; on rock surfaces, either on craggy summits, knobs, and
rock-walls, or on loose boulders......-......0.00¢e0e Lichen associations
Plants paella sticg in rocky or detrital situations, soil of variously
ani tg instr shrubs; of nate local and temporary occurrence;
frequent in areas recently ieee ae sess, + Sumac association
Dominant a Faia bie) punted coercieton
358 BOTANICAL GAZETTE [NOVEMBER
Associations generally intermediate or established in character (usually sub-
ase to primitive associations, but often in habitats apparently little
ed from the primitive condition); soil often of mixed or fine texture,
or PRT considerable humus content; vegetation usually less open and sparse
than in precedin
Typically developed in ean or semi-xerophytic habitats, which are of
general occurrence in the foothills region (these associations are conse-
quently extensive)
ominant plants evergreen trees; usually in rocky or coarse soil
Of Seeae an = xerophytic ueneters ee distributed in the
OOUHINS TOMI iso pck Bui ed a FUSES ws a e's ock pine association
Of Selativey | more xerophytic pharactess of ae Rite (east of the
range-crest) more southerly distribution than preceding
Pinyon-cedar association
Dominant plants deciduous trees or large thicket-forming shrubs; of
southerly distribution east of the range-crest; frequent in fine soil, and
ranging into less xerophytic habitats.............. Quercus association
Dominant plants shrubs
Shrubs tall and loosely branched, occurring mostly at and near the
mountain-front, in coarse or rocky soils...... Cercocarpus association
Shrubs low, Pep and densely branched, occurring mostly in the
foo
Plants i sere of northerly distribution, more frequent in the
hihiet fOCthIS ee eS Arctostaphylos association
Plants deciduous, of more a pesca more frequent in
the tower Soetn. o6s e k nothus association
Dominant plants herbaceous; veuetation grassland, eae mostly of
xerophytes
Dominant plants including plains short-grasses of surface-rooted habit;
lant population large and diverse, Foothills mixed grassland association
Dominant plants mostly tufted bunch-grasses of deeper-rooted habit
Bunch-grass association
Typically developed in mesophytic or semi-mesophytic habitats (which are
much less prays in the foothills than xerophytic habitats, being repre-
sented chiefly on slopes and in ravines and canyons)
Dominant ete evetureen trees... 55 2s sss Pseudotsuga association
Dominant plants deciduous trees
Typically bier along stream margins in open canyons
Populus-Salix stream-side association
Typically developed in less exposed situations cate preceding, as
bottoms of v-shaped ravines and moist shaded slo
Canyon en association
— developed in moist ravines or slopes with humus soil; or, 10
the higher foothills, in moist patches of the granite-gravel upland
pen association
Tgt7]} VESTAL—FOOTHILLS VEGETATION 359
Dénsinant plants shrubs, or rarely reaching tree size
Plants larger, comparatively well separated; plant unnosition variable;
ranging also into xerophytic habitats
Foothiils mixed shrub association
Plants smaller, low, closely set, usually in fine moist soil
Symphoricar pos association
Dominant plants herbaceous. . . . Foothills mesophytic grassland association
Descriptions of associations
The plant communities are described in the order of their
appearance in the foregoing synopsis. They are subject to greater
geographic variation than can be treated fully in this article;
mention is made, however, of the more considerable variations.
The space allotment is not always proportionate to the importance
or general interest attaching to the several associations; some are
already fairly well known, some are less variable or can be summed
up more concisely than others, and some have been less thoroughly
or less widely studied. An approach to a balanced treatment has
been sought by the use of a smaller type for statements of less
general significance, descriptions of minor or very local vegetation
divisions, and detailed passages included by way of illustration or
amplification.
Plant names, when appearing without citation of authorities, may be
understood to be as in CoULTER and NELson’s Manual (2), which in general
follows the usage recommended by the Vienna Congress. The unit of vege-
tation is the plant association, in the generally accepted sense; its distinctive
representations, appearances, or variants are spoken of as consocies; the terms
as used are described in an earlier article (24, p. 382, footnote). Index letters
attached to species names signify frequency or abundance or regularity of
occurrence, as follows: a, abundant; f, frequent; 7, infrequent; /, focal or
locally; ch, characteristic in the community or situation mention
It will be understood that the total number of species of iat occurring
in an area so extensive as that of this study is very large. No attempt has
been made to work out the complete floristics, or the floristic variation of the
several communities as represented in different localities. Field botanists
will remember that very many of the species making up the flora of a region are
rare, known from a single or very few stations, are in effect of very slight
ecological significance, so far as vegetation is concerned. A further consider-
able proportion is not found in extensive plant assemblages (as, in this study,
grass species occurring only in stream margins), and is not important as part
360 BOTANICAL GAZETTE [NOVEMBER
of the vegetation of the general area. Several or numerous species of certain
genera, again, may be of similar habitat distribution, so that a species of one
locality may be replaced in the same habitat in another locality by a second
species of that genus. Care has been taken to select species for the floristic
lists which are as representative over a considerable area as may be. In the
southern foothills, as in the plains of southern Colorado, many more plants of
southwestern derivation enter into the flora, particularly in the primitive
grassland and mixed grassland assemblages. Many are true desert plants; a
few cacti and chenopods and many composites fall in this group. That this
geographic variation from north to south is ecological as well as floristic should
be apparent. It is paralleled by a similar altitudinal variation in composition,
from the montane zone to the plains.
LICHEN ASSOCIATIONS
TUuCKERMAN (23); W1xt1AMs (27), lichens in the Black Hills; HERRE (7),
lichens of Mount Rose, Nevada; SHANTz (22, p. 187).—Fig. 2.
A considerable proportion of the area of the foothills is exposed
rock, and its vegetation, except in crevices, is mostly composed of
lichens. The study of lichen vegetation has usually been left to
the specialists in that group of plants, since they are so poorly ©
known to most other botanists. For this reason brief notes on
external appearance, as to color and vegetative form, are given
with the speciesnames. The writer is indebted to R. HEBER Howe,
Jr.,2 who has made the species determinations and examined this
part of the manuscript (fig. 2).
_ Dry surfaces, much exposed to sun and wind, occupy most of the
area of bare rock in the foothills. They slope considerably, so that
run-off is rapid and absorption minimal. The first lichens to
invade dry rock, forming primitive xerophytic stages of lichen
growth, are fine-grained crustose forms, notably the black-gray
Rinodina radiata Tuck. (?=R. thysanota Tuck.) and an indetermi-
nable lead-gray species which is especially characteristic. Theseare
soon followed, but not displaced, by lichens of an intermediate
stage, mostly coarser crustose forms; the gray-green Rinodina
oreina (Ach.) Wain. is a character species both locally and geogr: aph-
ically abundant. The established stage on dry rock is marked by
the gray-green small-foliose Lecanora rubina (Vill.) Wain. and the
2 Some of the crustose species were determined for Dr. Howe by H. E. Hasse;
the Stereocaulon by L. W. Ruwwpte.
€
1917] VESTAL—FOOTHILLS VEGETATION 361
larger-foliose, also gray-green, Parmelia conspersa (Ehrh.) Ach.,
which may be said to be the dominant and most frequent lichen of
exposed rock. Here also occur the gray-green crustose-foliose
Rhizocar pon geographicum (L.) DC., with Rinodina oreina persisting
from the preceding stage, and a few other species, including one or
two of Parmelia, Gyrophora erosa, and the large and peculiar
Gyrophora vellea (L.) Ach., in crisped-margined dirty-gray plates
©.25-2 inches in diameter, attached centrally beneath. These
Fic. 2.—Lichens on steep rock-wall of rather sheltered side-canyon opening north-
ward into Boulder canyon; dark masses at joints are cushions of Selaginella.
established stages appear to be self-perpetuating so long as physical
conditions of dry rock are unchanged.
Less exposed, but usually dry, surfaces, such as shaded rocks, overhangs,
surfaces dripping for some time after rains, recesses in joints, etc., hav
characteristic lichen assemblages and definite successions. The earlier lichens
include the yellow-green crustose Acarospora xanthophana (Nyl.) Fink (charac-
teristic and abundant), with Lecanora rubina, Rhizocarpon geographicum, and
Rinodina radiata. Acarospora persists in the established stages, which also
show the bright orange- sor crustose-foliose Caloplaca elegans (Link.) Th. Fr.
(characteristic and abundant), Parmelia conspersa, P. sulcata Tayl., P. conspersa
var. stenophylla? Ach., peters vellea, and other species. Considerably
less of the rock surface remains uncovered with lichens here than in the xero-
phytic situations, and the number of species is larger, although the area of this
362 BOTANICAL GAZETTE [NOVEMBER
habitat and its lichen assemblage is very much smaller. Caloplaca elegans and
Parmelia sulcata are frequent on scattered rocks and tree trunks in shaded
canyon-bottoms.
oist surfaces in humid recesses of the rocks show numerous lichen species,
mostly foliose, including Physcia aipolia (Ach.) Nyl. and a number of species
of Parmelia. osses grow with the lichens abundantly in these situations.
These distinctly humid recesses are scattered and infrequent in the foothill
region. A Cladonia, probably C. fimbriata (L.) Fr., is characteristic on moist
north-facing canyon slopes, amongst mesophytic herbs, or beside surface rocks.
A pulvinate, finely divided whitish fruticose lichen, Stereocaulon albicans Th.
Fr., has the growth-form of a pulvinate moss, being “rooted” in moist rock
crevices, although the aerial part is more or less exposed. It is infrequent.
SUMAC ASSOCIATION
Rossins (16, p. 46), distribution on Long Mesa near Boulder.
As indicated in the synopsis of associations, the shrubs of sumac (Rhus
cismontana Greene, which is so like R. glabra of the eastern states as to be
considered identical with it by some botanists) often form a new plant assem-
blage in denuded xerophytic situations. These are extremely variable, includ-
ing old roadways, rock talus below road embankments, quarries, or prospect
holes, stony hillsides where erosion or landslipping has removed much of the
plant cover, or places which have been burned. In the lower foothills, and at
the mountain-front, the sumac appears to be quite common after fires, the
slopes being too dry to allow the establishment of aspens, in most places. The
shrubs are usually separated, the sparse plant cover of the interspaces often
being composed of plants of the primitive grassland association. As developed
in the foothills, the assemblage shows no essential difference from the sumac
growths of many parts of the United States. In autumn the bright red coloring
of the leaves makes the community very conspicuous, so much so as to give an
exaggerated notion of its frequence of distribution.
FOOTHILLS PRIMITIVE GRASSLAND ASSOCIATION
CLEMENTS (1, pp. 9-12), gravel slide formation, half gravel slide formation,
in part; RAMALEY (12, pp. 124-128), Cercocarpus scrub, upland dry grass, and
foothill sagebrush-grass formations, in part; ScrovEer (21), gravel slide and
half gravel slide formations, in part.
The principal herbaceous growth of dry coarse-soil situations in
the foothills presents very great variability, and is very generally
distributed, occupying not only large areas by itself, oa oceutring
in mixture with shrubs and trees tion
It is perhaps not too much to say that oe a small proportion of
1917] VESTAL—FOOTHILLS VEGETATION . 363
the area in which the rock pine is of frequent occurrence is occupied
by actual forest; the usual vegetation of the pine-sprinkled upland
is open, the ground-cover is made up of associations of herbaceous
plants or low shrubs; prominent among these is the primitive
grassland. It enters largely into the ground-cover of other mixed
associations also, in which trees and shrubs other than rock pine
are conspicuous. The variability of such an open ground-cover as
€ primitive grassland is so great that no particular set of plants
can be said to characterize the whole community, although certain
features are common to all of its variants or consocies: (1) they
constitute the first vegetation in new and unfavorable habitats;
(2) this vegetation is sparse and open; (3) it is made up of an
assemblage of species typical of coarse soils and rather considerable
exposure to sun and wind, some more commonly in the plains, others
in the mountain region (many of these plants are common to
several of the consocies, though some few are typical only in the
more extreme developments of particular consocies-habitats, as
Erigeron compositus in packed granite-gravel); (4) as development
of vegetation proceeds in the several consocies, with accumulation
of the plant remains, closing of the plant cover, etc., they resemble
one another more closely, converging into a less open growth, which
may be known as the foothills dry grassland association, the next
higher in the genetic series. Many of the species of the primitive
grassland seem not to be particularly xerophytic, as Thlaspi
coloradense and Gilia aggregata, for these are active during the early
part of the season, when the moisture supply is ample. Such
plants are very widely distributed in the foothills and are not
characteristic of particular habitats nor of the species groupings
of particular plant communities.
A partial list of species of the primitive grassland follows:
SPECIES LIST: PRIMITIVE GRASSLAND
Selaginella densa (/) Phlox multiflora
Aristida longiseta (/) Gilia a
Stipa comata (J) Gilia pinnatifida
Bouteloua hirsuta (/) Phacelia a heterophylla (ch)
‘Koeleria cristata (ch) Oreocar
Sitanion brevifolium (2) Pentstemon humilis
364 BOTANICAL GAZETTE [NOVEMBER .
Arenaria Fendleri Chrysopsis villosa (ch)
ora Jamesii (ch) Chrysopsis spp. (ch)
Berberis olium Townsendia exscapa
Thlaspi shake Townsendia grandiflora
Physaria floribunda (/) Machaeranthera aspera
Lesquerella montana Helianthus pumilus
Sedum stenopetalum (ch) Hymenoxys floribunda (south)
Potentilla pennsylvanica strigosa __ Gaillardia aristata
Potentilla Hippiana Artemisia frigida (ch)
Astragalus Purshii Artemisia gnaphalodes var. (ch)
Geranium Parryi (ch) Senecio Nelsonii (ch)
Mentzelia spp.
The more important representations of the association in special habitats:
(1) The mixed consocies of mixed detrital slopes. This term may
applied to the very sparse plant community of slopes on which the fragments of
rock-débris are of all sizes, and in which as a result conditions for plant life
vary extremely locally. The vegetation may be regarded as a mosaic of dif-
ferent variants of primitive grassland, with the addition of certain components
from other vegetation types, as the lichen, shrub, and pine associations (see
figs. 4, 8).
(2) The Geranium-Chrysopsis consocies of unstable granite-gravel slopes,
in which the loose bunches of these two plants are the most frequent or the only
plants in the loose decomposed granite soil.
(3) The Artemisia frigida-Koeleria consocies of stony detrital slopes (rock
talus, frequently). The habitat is quite common though seldom very exten-
sive; the sage may be very abundant without the grass Koeleria; it is an im-
portant species in the northern Great Plains and in the mountains up to
10,000 ft.
(4) The compacted granite-gravel consocies. Dwarfed plants of Erigeron
compositus, Senecio Nelsonii, and a few other species are characteristic in level
or gently rolling top surfaces, on which the thin coarse soil has become com-
pacted into a hard floor (fig. 3). In its most extreme condition seen, the
Erigeron was the only plant, occupying less than 4 per cent of surface. Rather
infrequently, Potentilla Hippiana occupies these situations, forming a pure
growth which spreads vegetatively.
(5) The mat consocies of gravel slides. These habitats are more frequent
in the Pike’s Peak highland than in the Front Range proper, where they are
This plant has narrow pinnately 5-divided leaves, and appears to be quite
sess different from the entire or apically 3-divided form with dense white
canescence. With this structural difference is an apparently constant habitat differ-
ence; the di lly in very coarse soil, the other i in clay, abundant only
at the mountain-front. Itish tk on determine
e forms
Ges eis Ne eek a eas
1917] VESTAL—FOOTHILLS VEGETATION 365
best developed on south-facing slopes, commonly at the bottoms of open
canyons, beside graded roadways. Species of Gilia , Physaria, Phacelia,
Berberis, Gaillardia, and Pachylophus are chatactetiatic Gravel slides have
been studied by CLEMENTS, and by SCHNEWDER (21)
The primitive grassland is closely related to certain associations
of the Plains region, notably the mat association (9, D: 396; 34, Pp:
393), and the Gutierrezia-Artemisia association (24, p. 398), and to
the other primitive assemblages leading to short-grass. ‘It is more
generally distributed, as would be expected, at lower elevations
1G. 3.—Granite-gravel floor, with much bare surface, some primitive grassland,
and mats * A rctosta A ylos; in background rocky summit or knob, with scattered pines;
Flagstaff Mounta:
and more southerly parts of the mountain region, and in the more
exposed habitats. It probably occupies a larger proportion of the
total area in the lower parts of the Front Range than any of the
other associations in their unmixed condition.
ROCK PINE ASSOCIATION
CLEeMENTs (1); RAMALEY (10, 12, 14); Ropsrns and Dopps (18), distribu-
tion of conifers on the mesas near Boulder; SHAntz (22, p. 184); WATSON
(25, p. 207); Youne (28, p. 337)-
Pinus scopulorum, variously called the rock, western yellow,
or bull pine, is the important tree in the foothills. Its plasticity
366 BOTANICAL GAZETTE [NOVEMBER
is remarkable, growing in all kinds of soil, on slopes of every angle
and every direction, through wide variations in soil moisture,
evaporation, light, and temperature. Its wide geographic and
altitudinal range is an expression of this plasticity. In favorable
situations it grows rapidly, with straight trunk and branches
regularly arranged; in the more exposed places it is reduced in size,
and commonly gnarled and irregular. Distribution of the pines is
largely a matter of establishment, since the critical stages are seed
burial, germination, and the young seedling period. Crevices and
soil-filled spaces between rocks, usually of small area, afford lodging
places for the seeds; exposed summits and slopes of fine soil are
mostly covered with grassland. Small areas of soil deposition may
allow burial of many seeds, and consequent development of dense
young stands. Seeds germinate well in the tangled mats of
Ceanothus Fendleri (see -under Ceanothus association). The first
few years of the seedling are safely passed only when several favor-
able seasons are successive (at least in exposed situations), as shown
by RAMALEY (13, p. 30) for the high mesas near Boulder.
According as establishment is abundant or very sparse in a given
station, the growth is closed, giving a true pine forest, or scattered,
. resulting in the well known open or parklike appearance; this is a
mixed vegetation of which the pines form only one component.
They may later dominate the whole area if new pines can germinate
beneath, but on the whole the closed pine forest is relatively infre-
quent. Just how important an influence in the foothills fire has
been, and is, is very difficult to determine; it is said by some
residents that the whole region just north of Boulder Creek was
once much more extensively forested than now; but if fire is of
fairly frequent occurrence in a region, it is an environmental factor
to be taken into account. Its effect is wholly favorable to the
grasslands and primitive growths, at the expense of the pines
(fig. 4).
In the lower and more southerly parts of the foothills, dry grassland and
particularly primitive grassland form the ground cover in most areas of
scattered pines. The spiny shrub Ceanothus Fendleri is also commonly seen
between the trees. Away from the individual trees, and often even at their
very bases, the plant cover is mostly not different from its condition where
1917] VESTAL—FOOTHILLS VEGETATION 367
there are no pines. The trees frequently do modify conditions of growth for
ground plants, however, where pine needles accumulate, but this effect is very
local. Farther up, and to the north, and apparently more closely associated
with pine growths, the bearberry (see under Arctostaphylos association) is an
sees part of the ground-cover between scattered trees
niperus scopulorum is an infrequent though Scully conspicuous tree
alas found with the pines. Pseudotsuga mucronata also mixes in to some
extent, even in a few fairly xerophytic stations. Juniperus communis sibirica
is a ground shrub of infrequent occurrence. Pinus flexilis is very locally
represented, although not confined to the foothills. Pinus Murrayana, the
se 4.—Shallow ravine head; mostly grassland, with fine soil at bottom, and
thinn rae rockier soil on side-slopes; in coarse soil are numerous pines and Arcto-
stephylis (foreground); in middle ground a considerable reat of Prunus demissa
(leafless condition), occupying soil moist from seepage; April 1
lodgepole pine, of the montane zone, mixes with the rock pine in the upper
foothills. The rock pine is by no means absent from the montane zone, and is
even quite abundant there if the lodgepole is absent, as in the Pike’s Peak
highland generally.
e ae association in its unmixed form (practically closed forest) has
very few o spaces. Natural pruning of the lower branches is general. Old
needles strew ibe ground; the light is much reduced; the two influences, mulc
and shade, acting together or singly, exclude practically all ground plants from
the closest stands, and all but a few from less dense forests. ants of primitive
grassland very seldom persist in shac Relics of former vegetation are seen
in less advanced stages, including acted plants of Opuntia, Cercocar pus,
368 BOTANICAL GAZETTE [NOVEMBER
bunch-grasses, and others. A few species commonly found in the undergrowth
of unmixed but not densely shaded forest are Harbouria trachypleura, Aletes
acaulis, Senecio (one or two spp.), Solidago (several spp.), and Pentstemon
humilis. .
PINYON-CEDAR ASSOCIATION
CLEMENTS (1, p. 8), foothill woodland formation; SHANTZ (22, p. 184);
WATSON (25, pp. 205-207), cedar and pinyon formations.
The pinyon, or nut pine, Pinus edulis, and less abundantly the
cedar of the southern Rockies, Juniperus monosperma, are conspicu-
ous plants in the mountain-front of the southern part of the state
and in the adjoining foothills. Toward the south conditions are
generally more xerophytic at the mountain-front; there the rock
pines are common only in higher elevations; they are replaced below
by the pinyon. Like the rock pines farther north, the pinyons show
local extension eastward into the plains, in rocky habitats, such as
the canyon-walls of mck outcrops, and the bluff-crests of the plains
stream valleys.
Between the trees are plains or semi-desert plants, many southerly species
being present which are rare or absent farther north than about Colorado
Springs. One of the most notable of these is the candlestick cactus, Opuntia
arborescens, common at the mountain-front on rock-strewn slopes and mesas.
The pinyons (and to a smaller extent the cedars) are typically broadly
rounded, the diameter of the crown being usually as great as the height of the
tree, which is rarely more than 12-15 ft. The trees are usually separated so
that the crowns are distant from each other by a diameter or a little less, in the
closer stands. The writer has never seen a really closed pinyon forest in which
the crowns would form a continuous canopy. The interval between trees
rically developed. Where the habitat is extensive, the pinyons are quite
uniformly dotted over the general area. On rocky ridges and mesa-crests the
trees are in ragged lines, in small clumps, or irregularly scattered.
QUERCUS ASSOCIATION —
LEMENTS (1, p. 6) and SHANTz (22, p. 179), foothill thicket formation, in
part; WATSON (25, pp. 207-210), white oaks in the yellow pine association.
East of the range-crest oaks may be seen nearly as far north as
Denver; however, they form more extensive growths to the south-
ward. North of the Platte-Arkansas divide they are perhaps more
abundant at the mountain-front and in the Plum and Cherry Creek
1917] VESTAL—FOOTHILLS VEGETATION 369
valleys than in the foothills proper; they range into finer soils than
do the pines. In the foothills as well as at the mountain-front the
oaks may share mixed rocky slopes with local representations of
Cercocarpus, pinyon, rock pine, or grassland associations, or may
alternate with them. The extent to which they replace the rock
pine on south-facing foothill slopes is appreciable even north of
Perry Park, and is increasingly considerable southward. There
is no apparent reason why they would not grow north of their
—Alternation of mixed pms and oak forest, west of Castle Rock,
July rox “tall herbs conspicuous at bor
present limits in the mountain-front; some of them extend north
on the west side of the range-crest even into Wyoming (fig. 5).
e taxonomic condition of these oaks is one of confusion. RYDBERG’s
Flora of Colorado (19) lists 11 species, all occurring at or near the eastern
mountain-front. Quercus Fendleri appears to be distinct, much more xero-
phytic, more southerly in distribution. The intergradations with most of the
others are such that specific determinations are very difficult. CLEMENTS
mentions Quercus Gunnisonii as the chief species of the Manitou vicinity.
Certain Colorado botanists now speak of the doubtful oaks collectively, for the
present, simply as Quercus spp. The writer has thus far not been able to
distinguish different habitat groups within these Quercus spp. (cf. SHANTZ, 22,
P. 179).
37° BOTANICAL GAZETTE [NOVEMBER
So many of the oaks do not reach tree size that the assemblage in many
places presents the appearance of chaparral. As might be expected from their
wide range of habitat-tolerance, they vary considerably in appearance, from
shrubby scattered trees or stunted thickets, to low forest with mesophytic
undergrowth. In very favorable stations, as along streams in the southern
foothills, the oaks may reach a height of 20 ft. and more. The undergrowth in
ungrazed parts of the oak scrub has a decidedly mesophytic stamp during the
moister part of the season; Pulsatilla, Castilleja, Monarda, Calochortus,
Lupinus, Geranium, Galium boreale, Campanula, Thermopsis, Danthonia,
Pentstemon unilateralis, are typical of oak borders and less densely shaded parts
within. Dense closed shaded oak scrub shows abundance of a tall white-
flowered umbellifer, Ligusticum Porteri (?).4 Late summer shows many of the
less xerophytic composites, including species of Aster, Solidago, Erigeron, and
Brickellia grandiflora var. minor. The undisturbed clumps of small oak trees,
where these alternate with dry grassland, are often bordered with tall, rather
mesophytic herbs, as Lupinus argenteus, Monarda spp., and Achillea millefolium
L. (A. lanulosa Nutt.), as may be seen in fig. 5, taken west of Castle Rock.
Low scrubby oak thickets, in grazed areas, are mostly impenetrable to
horses and cattle; they are, however, eaten from the outside, and the patches
thus slowly reduced in area. This results in a complete replacement of oak
by grassland, as stated by SHANTz (22, pp. 182, 203). When, however, the
height of the small trunks in the middle of a clump becomes too great for the
animals to reach the top leaves, their safety is assured. In these taller growths
the lower parts of the trees are much less dense; if there is no outer border of
dense thicket, grazing animals are enabled to enter; the assemblage is now 4
scrubby forest of low trees, with open spaces between the trunks and very
scanty undergrowth, as in fig. 6. Grazing animals may thus have a large part
in determining the character and distribution of the oak vegetation.
CERCOCARPUS ASSOCIATION
CLEMENTS (r, p. 6) and SHANTz (22, p. 179), foothill thicket formation, in
rt; RAMALEY (12, pp. 124-126), Cercocarpus shrub formation;
pace (15), local distribution in a square mile of rock Siee and foothills;
SCHNEIDER (21, p. 292), thicket of south slopes, in part.
Ragged shrubs of Cercocarpus parvifolius, or, as it is called,
mountain mahogany, form a characteristic vegetation in dry
exposed rocky places, particularly along the mountain-front, on
butte-slopes, hogback ridges, stony mesa-crests; in the foothills
it is most abundant on south-facing side-slopes, or on the outermost
slopes facing eastward on the plains. The stony fragments of the
4 Either L. Porteri C. and R., or L. affine A. Nels., as determined by E. E. SHERFF.
1917] VESTAL—FOOTHILLS VEGETATION 371
soil vary from those of coarse granite-gravel to the variously sized
blocks of rock talus.
The shrubs are 2-5 ft. high, very loose in habit, with few branches and
reduced leaf surface. The fruits are provided with long plumed awns. e
plants are separated, being regularly spaced like the pinyons, the intervals
likewise varying with degree of exposure. The habitat relations of Cercocarpus
are in fact quite like those of the pinyon, and it is north of the pinyon area that
the mountain mahogany association is best developed. The interspaces
Fic. 6.—Open grove aspect of oak assemblage, caused by entrance of grazing
animals, ca Park; open mixed grassland in coarse soil occupies foreground.
between plants may be almost bare, or may be occupied by a sparse growth of
xerophytes, most of them plains plants or representatives of the primitive
grassland, the mat growth-form being common
ARCTOSTAPHYLOS ASSOCIATION
Cow Les (3, p. 367) and Gates (6, p.-306), Lake Michigan dunes; Wuit-
FORD (26, p. 298), northern Michigan. In the Colorado foothills: RoBBins
(16, p. 44); SCHNEIDER (21, p. 299); SHANTZ (22, p. 186).
The Arctostaphylos-Juniperus association of the northeastern
coniferous forest region is very well known to students of vegetation.
Practically the same community is represented in the Rocky Moun-
tains, associated there as elsewhere with coniferous vegetation.
The same plant species and the same creeping habit are seen. The
372 BOTANICAL GAZETTE [NOVEMBER
important difference, as seen in the Front Range foothills, is that
the juniper is very infrequently seen, the Arctostaphylos mostly
dominating alone.
Conditions of soil-moisture, soil-texture, position, slope, and exposure
are varied. The creeping mats of bearberry are seen on rock, in gravelly
shaded and sunny, and through a considerable range in altitude. The growth
is more extensive and more frequent, however, away from the mountain-front,
at elevations 800-1200 ft. above the lower limit of rock pine, being increasingly
abundant from that height upward, and being perhaps more typical of montane
than of foothills vegetation. Its most frequent habitat in the foothills is the
rolling floor of the granitic upland, the soil of which is thin, coarse, mostly
compacted (granite-gravel). Here the conspicuous vegetation is rock pine,
in open array of scattered clumps and single trees. Parts of the treeless
surface are occupied by large mats of Arctostaphylos, with admixture of Ceano-
thus Fendleri (less of this upward); the rest of the area is bare or nearly so, with
a few scattered herbaceous plants, mostly of primitive grassland.
CEANOTHUS ASSOCIATION
RosBIns (16, p. 41); WATSON (25, p. 207).
_ Thespiny shrub, Ceanothus Fendleri, is ecologically similar to Arctostaphylos
in many respects. It forms a low, matlike, spreading ground cover, and occurs
to some extent in mixture with bearberry mats. It differs from the other in
being typical of more exposed and xerophytic slopes, in being abundant at
lower eh and more southerly in geographic distribution. M1iarp S.
MarkLE informs the writer that the Ceanothus community is important in the
Sandia Mountains of New Mexico, occurring frequently with the oaks and with
Robinia neo-mexicana. Ceanothus ranges into dry fine-soiled habitats more
frequently than Arcieslotiedes: and is closely associated with grassland, rather
than pine forest. It is not evergreen. :
Ceanothus shrubs occur in closely set or scattered patches, mostly in
unstable gravelly or finer soil of detrital slopes. They have a strongly accelera-
tive part in vegetation-development. Their numerous twigs and thorns, even
in the leafless winter condition, catch and hold wind-blown and washed-down
soil particles and bits of plant débris, thus stabilizing and adding to the soil, and
accumulating humus. In one station this had even resulted in the building of
small dunes of wind-blown dust, of about 8 inches height and 18 inches diameter.
Seed burial is favored in these mats, as well as germination. Some of the more
mesophytic of the foothills plants are seen growing up through the tangled
branches; pine seedlings also germinate in the shelter of Ceanothus, which may
thus be an important factor in reforestation. On dry, burnt slopes Ceanothus
frequently covers a considerable proportion of surface and, with the Rhus
cismontana shrub growth, is an important stage in succession after burns.
1917] VESTAL~—FOOTHILLS VEGETATION 373
Ceanothus mollissimus and what appears to be Ceanothus subsericeus Rydb.
occasionally occur with the spiny species, in the less xerophytic stations.
Ceanothus velutinus is rare in the lower foothills, but is frequent at higher
elevations and farther north. Herbs of the primitive grassland and mixed
grassland commonly grow out from between the twigs of Ceanothus Fendleri,
and to some extent are seen in the spaces between the mats.
FOOTHILLS MIXED GRASSLAND ASSOCIATION
CLEMENTS (1), ground-cover in the foothill thicket and pine formations,
in part; RAMALEY (12), foothill sagebrush-grass formation; SCHNEIDER (21),
half gravel slide formation, and grassland of north slopes; SHANTZ (22),
outeloua formation, in part: its modified form at the mountain-front; VESTAL
(24, p. 386), Bouteloua mixed consocies, as developed at the mountain-front;
WATSON (25, pp. 209, 210), herbaceous ground-cover in the yellow pine asso-
ciation, and mountain “meadows.”
The mixed grassland association normally develops from primi-
tive grassland, one of its important féatures being the establishment
of the dominant Bouteloua oligostachya, the grama grass of the
plains. It thus differs from the primitive grassland in that (1)
the ground cover is less open, though still generally xerophytic;
(2) the soil is usually more stable (in most situations a physical
cause, rather than the effect, of the more permanent vegetation) ;
(3) the soil is more finely broken up, and to it may be added con-
siderable humus; and (4) a number of plains, prairie, and foothill
species absent or rare in the primitive grassland are established.
The assemblage is most heterogeneous, since the many plants include
widely diverse ecological, geographic, and floristic types. Extreme xerophytes
and relatively mesophytic plants, plants of widely varying growth-form and
seasonal relations, of great difference in plasticity to environmental variation,
in altitudinal and habitat range, may occur in the same small grassland area.
This mixed vegetation is really very closely allied to the modified plains grass-
land mentioned as the Bouteloua mixed consocies of the short-grass association
(24, p. 386). This is found in the mixed mesa soils of the mountain-front zone
eae oui the foothills. The conditions which would result in heterogeneity
of th tation are probably similar in the lower foothills to those of
= mountain-front; some of these are given in the article cited (24, pp. 381,
82).
. So many species occur regularly in the mixed grassland, and the variability
in ‘flocistic composition in particular stations is so great, that a selected list
ee habitats cannot be
374 BOTANICAL GAZETTE [NOVEMBER
given. By way of illustration, however, a list of the plants observed in a
particular mixed grassland station may be presented, and this is followed by a
list of some other species commonly found in the community, but which happen
to have been absent from the station selected. The station is on the east slope,
not far from the top, of a hill a little over two miles west of the mountain-front
and a little north of Boulder, in section 36,T 2N,R72W. The hill is marked
in the Boulder quadrangle of the United States topographic atlas by the altitude
of its summit, 7168 ft. The spot studied most in detail is at about 7000 ft.;
exposure is considerable, as the slope is even and treeless; drainage is probably
quite rapid; the soil coarse, with but little humus; proportion of bare surface
about 15 per cent on June 18, when the list was made. All of the plants
marked as abundant or frequent occur in practically every square meter of
surface.
PLANT COMPOSITION OF A TYPICAL MIXED GRASSLAND STATION
Bouteloua oligostachya (a) Eriogonum umbellatum (2)
Phacelia heterophylla (a)
Chrysopsis villosa (?) (a)
Senecio oblanceolatus (a)
Geranium Parryi (a)
Artemisia frigida (a)
Aragallus Lambertii (a)
)
Ceras se
Aragallus albiflorus (//)
Stipa comata (/f)
Opuntia fumes (2)
Oreocarya virgata (7)
Artemisia eetiai is var. (i)
Astragalus flexuosus (7)
Eriocoma cuspidata (7)
Mamillaria vivipara (2)
Sitanion brevifolium (7)
Gaillardia aristata (7)
Phlox multiflora (2)
Potentilla pennsylvanica strigosa (7)
Euphorbia robusta (2)
Townsendia grandiflora (7)
Allium sp. (2)
The order in which the species are listed gives a rough approximation of
their relative importance as making up a part of the vegetation, in descending
e. The names of plant species elsewhere frequent in the association follow:
ADDITIONAL SPECIES FREQUENT IN MIXED GRASSLAND
Woodsia oregana
Selaginella, two spp.
Aristida longiseta
Echinocereus viridiflorus
Lithospermum multiflorum
1917]
Poa Fendleriana
Agropyron Smithii
Elymus triticoides
Leucocrinum montanum
Calochortus Gunnisonii
Yucca glauca
Zygadenus intermedius
Comandra pallida
Allionia linearis et spp.
Pulsatilla hirsutissima
Argemone intermedia
Corydalis aurea
Draba spp.
Erysimum asperum
Potentilla spp.
Astragalus spp.
soralea tenuiflora
Malvastrum coccineum
Viola Nuttallii
VESTAL—FOOTHILLS VEGETATION
Onosmodium occidentale
Pentstemon humilis et spp.
Castilleja integra et spp.
Campanula rotundifolia
Liatris punctata
Grindelia squarrosa
Chrysopsis spp.
Solidago spp.
Aster spp.
Machaeranthera aspera et spp.
Erigeron spp.
Ratibida columnaris
Helianthus spp.
Hymenopappus filifolius
Hymenoxys floribunda
Artemisia aromatica
Artemisia canadensis
Senecio plattensis et spp.
Senecio spartioides
375
Mentzelia spp. Nothocalais cuspidata
As regards distribution of the mixed grassland association in the foothills,
it may be said that the primitive grassland is more frequent and occupies areas
of greater extent, because of the general instability and rocky character of the
sloping surfaces. In the upper foothills mixed grassland is absent from com-
pacted soil level or rolling surfaces generally occupied by pine and Arcto-
staphylos, etc., but dominates on the more exposed mountain sides, which are
treeless. The mixed grassland, like primitive grassland, is subject to a gradual
ecological and floristic variation, from the south northward, and from the short-
grass of the plains to the montane dry grassland of elevations from 8500 to
10,000 ft.
BUNCH-GRASS ASSOCIATION
CLeMENTs (1, p. 6), Andropogon, etc.; SCHNEIDER (21), half gravel slide
formation, in part; SHANTZ (22, p. 43), Bouteloua hirsuta uta consocies, with
Andropogon spp., Atheropogon, etc.; VESTAL (24, pp. 3 388-390), bunch-grass
association: photograph and citation to descriptions in other regions; WATSON
(25, p. 209), Andropogon, etc.
The bunch-grass vegetation of the foothills is quite similar to
that of the mountain-front and over the whole prairie region,
including most of the same species, but containing in addition other
grasses of similar growth-form but of different geographic distribu-
tion. With the bunch-grasses are many composites and other
376 BOTANICAL GAZETTE [NOVEMBER
plants of the mixed grassland, such as Liatris, Chrysopsis, Eriogo-
num ‘alatum, etc. The tufted bunch-grass growth-form is well
known; the roots are deep and numerous; the plants are mostly
late in flowering; they are active during the whole growing season,
depending on a constant moisture supply. The chief habitats in
the foothills which satisfy this condition are rocky or very coarse
gravelly slopes, exposed and dry at the surface, but with rather
more moisture beneath than in most areas of mixed grassland;
these situations are consequently rather locally developed only.
PRAIRIE BUNCH-GRASSES OCCURRING IN FOOTHILLS
Andropogon scoparius (a) Muhlenbergia gracilis (/)
Andropogon furcatus (a) Sporobolus heterolepis (//)
Hilaria Jamesii (Ji) Atheropogon curtipendulus (/)
Sorghastrum nutans (/f) Koeleria cristata (f)
OTHER FOOTHILLS PLANTS OF BUNCH-GRASS TYPE
Trisetum montanum (/) Agropyron spicatum
Festuca confinis (/) Sitanion longifolium
Agropyron occidentale (J) (?)Elymus triticoides
Hilaria is a southern plant and has not been seen north of about Canyon
City. Sorghastrum and Hilaria appear not to extend far into the foothills.
Koeleria ranges into many widely varying habitats and is found with many
different plant assemblages. This may partly be due to its early ripening (it
‘flowers in June), which may allow it to escape the dryness of the latter part of
the season. Most of the plants of the second group bloom in early summer also;
they are frequently found in clumps of one species, in rock crevices or coarse
so risetum ranges into the montane zone, but not into the plains; it is
restricted to moister places than most of the others. Agropyron spicatum is
one of the chief dominants of the extensive grassland areas in the northwestern
states, in intermontane valleys and the Columbia Basin plains. It too matures
early in summer and is dried up the rest of the season. Elymus triticoides is
included with some hesitation; it may be more like the grasses of the primitive
bunch-grass type (24, p. 307).
PSEUDOTSUGA ASSOCIATION
CLEMENTS (1, p. 14); SCHNEIDER (21, pp. 299, 300), with list of herbaceous
plants; RAMALEY (14, pp. 251, 262); WaTSON (25, p. 211); YOUNG (28, p- 343):
The Douglas “spruce,” Pseudotsuga mucronata, is, like the rock
pine, one of the most abundant and widely distributed conifers of
1917] VESTAL—FOOTHILLS VEGETATION 377
western North America, but in the foothills of the Front Range in
Colorado it is relatively very local in occurrence. It is frequent
only on north-facing slopes and in canyons, where the snow lies
deep and late. It grows in close stands or as scattered trees (fig. 7).
Small trees of Juniperus scopulorum may occur infrequently in the Pseudo-
tsuga forest; in unshaded areas with moist soil a few aspens may be found.
Arctostaphylos and the prostrate Juniperus communis sibirica, so frequently
associated with it, are seen as relics. The moist and sheltered slopes on which
Pseudotsuga grows may in its stead be covered by the mesophytic grassland
association, and many of its plants occur scattered among the conifers, such as
Fics. 7, 8.—Fig. 7, Pseudotsuga association on a north slope; fig. 8, another
ot, view, showing prevalence of grassland on side-slopes; trees conspicuous in
profiles of distant slopes.
Mertensia spp., Campanula rotundifolia, Pulsatilla hirsutissima, Saxifraga
rhomboidea, Aster laevis, and one or two small ferns.
e rock pine grows well in the moist habitats of the Pseudotsuga, if the
young trees can get a start, and so the two species are commonly found in
mixture, especially toward the top of canyon-slopes and in other less protected
ces, Pseudotsuga can range into the habitats of the pine, where, how-
ever, it is usually of less symmetrically spire-shaped form, and with fewer and
uneven branches, so that the growth habit resembles that of the pine.
POPULIS-SALIX STREAM-SIDE ASSOCIATION
RAMALEY (12, p. 127, 14), part of the canyon forest formation; WATSON
(25, p. 21), Populus angustifolia society; YouNG (28, pp. 330-33
The poplars and willows of stream-sides form a nearly continuous belt in
the wider and more open canyon-bottoms of the foothills. Populus angustifolia,
378 BOTANICAL GAZETTE [NOVEMBER
the narrow-leaved cottonwood, is the largest and most frequent species. The
willows include Salix irrorata and S. exiguus, forming shrubby clumps; and S.
Bebbiana, S. amygdaloides, and S. lasiandra, small trees. The hackberry,
Celtis reticulata, is perhaps more typically found scattered along stream-sides in
quite exposed places than with other trees. It is also common in such habitats
in New Mexico. Certain plants common in the canyon forest are also quite
characteristic, in the rather less exposed stream-side situations, replacing the
cottonwoods and willows in small areas, or intermingling with them. Such
plants are Alnus tenuifolia, Betula fontinalis, Acer Negundo, and the shrubby
Cornus stolonifera. Scattered plants of the mixed shrub association are also
frequently seen: Bossekia, Ribes, Rosa, Crataegus, Prunus demissa, and others.
CANYON FOREST ASSOCIATION
RAMALEY (12, p. 127); Younc (28, PP. 333, 335), Alnus-Betula-Corylus
assemblage; (/.c., p. 334), Crataegus assemblage, etc.; DANIELS (4, pp. 21, 27)-
The canyon forest, which contains many of the deciduous tree
species of the foothills, is typically developed in local mesophytic
stations, such as the slopes and bottoms of narrow canyons, in
which the soil is moist (usually from seepage), and the air compara-
tively humid, due to the shade and the shelter from wind. A
selected list of species is here given:
PLANTS OF FOOTHILLS CANYON FOREST ASSOCIATION
Trees
Alnus tenuifolia Prunus american
Betula fontinalis Prunus demissa (N utt.) Dietr.s (ch)
Salix Bebbiana (2) Robinia neomexicana (
Populus tremuloides (i) Acer glabrum (ch)
Amelanchier alnifolia (/z) Acer Negundo (/)
runus pennsylvanica (ch) Crataegus coloradensis et spp.
Shrubs
Corylus rostrata (/) Rhus Rydbergii (2)
Ribes longiflorum Vitis vulpina (/)
Physocarpus Ramaleyi (i) Parthenocissus vitacea (/)
Rosa Sayi et spp. Viburnum pauciflorum (/)
$ Jones (8, p. 35) fails “‘to see any ground for Netson’s P. melanocarpa, 2
though Nutra. describes his as red-fruited, for we know that this species has
red till dead ripe, when it turns black,”
1917} VESTAL—FOOTHILLS VEGETATION 379
Herbs
Pteridium aquilinum Fragaria OE et spp.
Smilacina stellata (ch) Aralia nudicauli
Smilacina amplexicaulis (ch) Viola ade Rydbergii (ch)
Stellaria Jamesiana astilleja miniata et s
Thalictrum spp. Monarda Ramaleyi et spp.
Aquilegia coloradensis Hydrophyllum Fendleri (ch)
Delphinium Nelsonii (ch) Galium boreale (ch)
Ligusticum Porteri (?) Galium aparine
Saxifraga rhomboidea (ch) Galium Vaillantii
The canyon forest presents a wide range of variability, according
as favorable ground conditions are uniform or interrupted; thus
in rocky canyon-bottoms and slopes it is patchy in development.
It may merge into, or mingle with, areas of Pseudotsuga, mixed
shrub, aspen, Populus-Salix, Quercus, and moist grassland growths.
The herbs especially may be no more typical of unmixed meso-
phytic deciduous forest than of many other mesophytic habitats.
The characteristic plants growing in the shade of large shrubs and
trees are Viola, Hydrophyllum, and one or more species of Galiwm.
These are abundant in unmixed canyon forest, at least in the
northern foothills.
Amelanchier is an important component only in the upper foothills and the
montane zone, or farther north and west in the Rocky Mountains. Acer
glabrum often occurs by itself on north or shaded slopes, the bushy plants
10-15 ft. in height, and in most places considerably separated. Prunus
demissa, and several species of Crataegus (mostly C. coloradensis and C. cer-
ronis), together or singly, dominate tall thickets or low forests, which may be
regarded as transitional cnapbabaniae te mixed shrub and canyon forest associa-
tions. In new growths or they are low and scrubby; in other
places they form a taller and ‘closed growth, with a lower stratum of mesophytic
herbs, and may properly be spoken of as forest. Prunus demissa and Crataegus
form relatively much more extensive areas of vegetation in the northern foot-
hills and especially along the northern mountain-front than in the southern part
of Colorado. Robinia is abundant in the southern third of the foothills area.
It ranges into drier habitats, in which it is low and scrubby.
The Alnus-Betula consocies has been mentioned as being abundant along
mesophytic stream-sides. Corylus is frequent only in such situations, occurring
in places alone, in others with Alnus and Betula. The climbers, clematis,
Virginia creeper, and grape, are local, and more common in sunny openings.
Viburnum is in moist canyon-bottoms of the higher foothills.
380 BOTANICAL GAZETTE [NOVEMBER
ASPEN ASSOCIATION
RAMALEY (14, p. 251); YOUNG (28, p. 347).
Botanists are familiar with the réle of Populus tremuloides in revegetation
of burned areas, and it is prominent in the montane zone in Colorado in this
capacity. The general area of the lower foothills, however, is too dry for
establishment of aspens, and they occur only locally, in ravines even more
mesophytic, perhaps, than the ordinary habitat of the canyon forest. Thus
in the Boulder area the stations below 7200 ft. in which aspens have been
observed in local abundance are very infrequent. Such stations are usually
in sheltered ravines with deep humous soil, abundantly moist. The trees in
places are large, the undergrowth very mesophytic, with Thalictrum, Heracleum,
Castilleja spp., etc., and particularly Aquilegia coerulea. At about 7800 ft. in
the same vicinity aspens begin to appear in small clumps on the granite-
gravel upland, among more frequent clumps of rock pines. No connection
with former fires could here be made out; appearances indicated that perhaps
there the aspens might be associated with the moist patches resulting from the
tardy disappearance of the deeper snowdrifts of winter. The conspicuous
yellow color of the aspens in fall probably tends to exaggerate the popular
notion of their frequency of occurrence.
MIXED SHRUB ASSOCIATION
DANIELS (4, p. 20); RAMALEY (12, p. 127), shrubs of the canyon forest;
SHANTZ (22, p. 179), thicket formation, in part; notes on distribution and eco-
logical relations of the species; RAMALEY (11); ROBBINS (16); SCHNEIDER (20).
The shrub associations of the foothills, like the deciduous tree
growths, are generally found in rocky or coarse soil stations with
constant moisture supply in the substratum, which is reached by the
deep root systems. Local distribution, as in the case of the pines,
is probably restricted by unfavorable conditions for germination
over a large part of the general area. It has been observed that, on
irregular slopes where the distribution of snow in late spring is
uneven, the shrubs occupy the moister spots determined by the
deeper snow patches. In deep moist soil it is likely that the shrubs
are soon succeeded by trees, as has been observed in some stations.
The shrub species most commonly found appear in the following
selected list. Certain of the canyon forest plants which occur with
the shrubs in the less mesophytic stations without attaining tree
size are included here also. It is significant that so many of the
1917] VESTAL—FOOTHILLS VEGETATION 381
shrubs, and some of the canyon forest plants, have fleshy fruits, and
so may be distributed by birds.
PLANTS OF FOOTHILLS MIXED SHRUB ASSOCIATION
Ribes saxosum Rosa aro
Ribes pumilum Rosa Fendleri
Ribes vallicola recone alnifolia (7)
Ribes longiflorum (J) Crataegus cerronis
Jamesia americana (/) Crataegus coloradensis
Holodiscus dumosus (/) Prunus americana (ch)
Physocarpus intermedius (/) Prunus demissa (ch)
Physocarpus monogynus (/) Robinia neo-mexicana (/)
Bossekia deliciosa (f, ch) Rhus trilobata (ch)
Rubus strigosus (/) Ceanothus subsericeus
Rosa Sayi
Amelanchier has been mentioned as being rare in the northern foothills, as
may be said also for Holodiscus. The common shrubs of rock-crevice habitats
are Jamesia and Ribes pumilum. The yellow-flowered Ribes longiflorum,
unlike the others of the genus, is more frequent in deep, moist, fine-grained
soil than in rocky or coarse soil. Rubus strigosus is more common in the upper
foothills, and in less exposed habitats. It and the roses are smaller than most
of the other shrubs. Prunus americana forms low dense thickets in rather
exposed places. Robinia is southern. Rhus trilobata ranges into very xero-
phytic habitats, and can persist and even establish itself on unstable soil of
steep or loose slopes. Although a single species may make up the shrub vege-
tation at any one spot, numbers of them occur together in a very large variety
of combinations, particularly where the habitat is internally diverse. The
shrub association, and consequently have been separated from it.
relation of the mixed shrub association to the canyon forest has already been
mentioned; the two grade into each other, but in the main they are quite
Where the shrubs grow close together, a mesophytic undergrowth of
herbs develops. Galium aparine or G. Vaillantii, Delphinium Nelsonii, and
Viola canadensis Rydbergii are frequent species. The border of many shrub
areas, where there is no grazing, shows tall herbs, as Lupinus, Achillea,
Monarda, Pentstemon unilateralis, etc. Surface rocks, where present in
grassland, may allow the scattering admixture of a shrub element, or even,
where the soil is sufficiently moist, invasion of shrubs over the general
area.
382 BOTANICAL GAZETTE [NOVEMBER
SYMPHORICARPOS ASSOCIATION
Y (12, pp. 127, 128); RoBBINs (16, p. 38).
The Symphoricarpos association is best iad in moist, fine-grained
soil; best seen, in the foothills, on basal or other deep-soiled detrital slopes,
clay or loam, with or without humus. The common species of the Colorado
foothills is Symphoricarpos occidentalis. The bushes are low, are spaced very
close together, and are profusely branched, giving the whole growth a very
compact and uniformly dense structure, especially where subject to grazing, as
in many stations. From its habitat relations, the bush honeysuckle, as it may
be called (it is known in some localities as buckbrush), adjoins a semi-meso-
phytic grassland in most places, competing and alternating sharply with it.
Many of the taller mesophytic herbs are seen at the border, including Frasera
speciosa, Thermopsis divaricarpa, the others already mentioned as bordering
canyon forest and mixed shrub, and frequently the tall grass Stipa viridula.
This border condition is best seen where the Symphoricarpos assemblage
occupies a depression.
The shrub area is dominated by the one species, although bushes of Rosa
arkansana are mixed in, abundantly in places, and Berberis aquifolia may also
be seen. A few herbs may occur underneath.
Symphoricarpos in places forms a border between mixed shrub or canyon
forest vegetation and grassland.
MESOPHYTIC GRASSLAND ASSOCIATION
RAMALEY (12, p. 129), meadow formation.
There are several kinds of herbaceous vegetation in the foothills, of meso-
phytic or semi-mesophytic character, which may for convenience be considered
together. There is a meadow growth, which shades more or less completely
into the western prairie-grass of the mountain-front (24, p. 390), on the one
hand, and into the forest border and forest undergrowth assemblages on the
other. On certain shaded ravine slopes a mixture of mesophytic herbs from
several of these assemblages has been observed, apparently independent of any
tree canopy. The trees affect the herbs, apparently, mainly or wholly by their
modification of physical conditions. A selected list of mesophytic and semi-
mesophytic species may be given:
MESOPHYTIC AND SEMI-MESOPHYTIC HERBS OF FOOTHILLS
Stipa viridula (ch) Gentiana affinis
Danthonia Parryi (f) Frasera speciosa (ch)
Poa pratensis Mertensia ciliata
‘oa Buckleyana Mertensia lanceola
Agropyrum violaceum Monarda canner (ch)
1917] VESTAL—FOOTHILLS VEGETATION 383
Calochortus Gunnisonii Pentstemon humilis (/a)
Zygadenus intermedius (ch) - Pentstemon unilateralis
Iris missouriensis (/2) Castilleja linariaefolia (ch)
‘ Claytonia virginiana Castilleja sulphurea
Cerastium arvense (ch) Orthocarpus luteus
Delphinium Nelsonii (ch) Galium boreale (ch
Thlaspi coloradense (?) Ca eo. recer rotundifolia
Erysimum Wheeleri (ch) Aster laevi
Saxifraga rhomboidea (ch) Erigeron fee
Potentilla pennsylvanica strigosa (ch) Achillea millefolium
Thermopsis divaricarpa (ch) Arnica cordifoli
rni
ca fulgens (/a
Senecio integerrimus (/a)
©
pa
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=)
wn
ca.
Viola canadensis Rydbergii
The prairie grass aspect has already been mentioned, and a description
cited. The foothill meadow assemblage in early summer typically shows
such conspicuous plants as Delphinium, Cerastium, Arnica, Senecio, and
sag linariaefolia (C. sulphurea is frequent only in the higher eleva-
ons). The mixed shrub association frequently alternates with meadow, and
eck upon it, and is bordered by the taller herbs with that assemblage.
The forest border and forest undergrowth communities have also been
mentioned.
oist rock crevices in sheltered ravines become overgrown with cushions of
Selaginella (fig. 2) and smaller cushions of mosses; humus accumulates by the
growth and death of these plants; in this Seiinias rhomboidea and later other
herbaceous or woody plants may become established. This is a very common
successional series from oad rock in mesophytic habitats.
Herbaceo eous plants commonly seen scattered along the moist soil of stream
margins, in open dauae include Rumex sp., Heracleum lanatum, Thermopsis,
and Lupinus, with certain grasses, as Muhlenbergia racemosa, Eatonia obtu-
Sata, etc.
Hygrophilous and amphibious ‘Plants of the canyon streams may for
convenience be mentioned at this point. Marchantia polymorpha is found on a
very few stream —- on ‘ie: or in crevices in sheltered spots. Many
mosses may accompany it, especially where some soil accumulates in cracks of
stream-side boulders, etc. Dodecatheon radicatum may here be found, or
species of Ranunculus in boggy places. A number of species are seen in
these very restricted boggy places. Mimulus Langsdorfii and Veronica
americana may grow there or in quiet little pools of the stream itself.
RaMALEY has given these growths the name Stream Bank Marsh Society
(2, p. 227).
Eastern Intivors STATE NorMAL SCHOOL
CHARLESTON,
384 BOTANICAL GAZETTE [NOVEMBER
LITERATURE CITED
1. CLEMENTS, F. E., oT and succession herbaria. Univ. Neb.
Studies 4:329-355. 190.
. CouLTER, J. M., and Necoak 7 ats manual of botany of the Central,
Rocky Mountains New York.
- Cowtes, H. C., The ‘sage acid of the sand dunes of Lake
Michigan. Bor. Gaz. 27:95, 167, 281, 361. 1899.
4. DAntets, F. P., The flora of apa Colorado, and vicinity. Univ. Mo.
Studies 2 (Sthenice Series): no. 2; pp. xiv+31I. IgII.
5. Davis, W. M., The Colorado Foc Raee Ann. Ass. Am. Geog. 1: 21-83.
IQIt.
GatTEs, F. C., The Nisiceeae of the beach area in northeastern Illinois and
southeastern Wiscon: Bull. Ill. State Lab. Nat. Hist. 9:251-372- 1912.
Herre, A. W. C. T., "The lichens of Mount Rose, Nevada. Bor. Gaz
55°392-396. 1913.
8. Jones, M. E., Montana a notes. Univ. Mont. Bull. no. 61 (Biol.
Series no. iy pp. I-75. 19
9. Pounn, R., and CLEMENTS, Fr E., The phytogeography of Nebraska. 2d
ed. Lincoln. pp. 442. 1900.
10. RAMALEY, F., Plant zones in the Rocky Mountains of Colorado. Science
26:642-643. 1907.
, Woody plants of Boulder County. Univ. Colo. Studies 5:47-63-
N
w
>
=
1907.
, Botany of northeastern Larimer County, Colorado. Univ. Colo.
Studies §:119-131. 1908.
, Climatology of the mesas near Boulder. Univ. Colo. Studies
13.
6:19-31. 1908.
14. , Forest formations and forest trees of Colorado. Univ. Colo.
Studies 6:249-281. 1909
15. RAMALEY, F., and Rossins, W. W., Ecological notes from north-central
Colorado. Univ. Colo. Studies §:111-117. 1908.
16. Rossins, W. W., Distribution of deciduous trees and shrubs on the mesas.
Univ. Colo. Studies 6:36-49. 1908.
, Climatology and vegetation in Colorado. Bor. Gaz. 49:256-280-
IQIo.
18. Ropsins, W. W., and tea ns S., Distribution of conifers on the mesas.
Univ. Colo. Studies 6:31-
19. RyDBERG, P. A., Flora of Cra Bull. 100, Exp. Sta. Colo. Agr. Coll.
Fort Collins. pp. 448. 1
20. SCHNEIDER, E. C., The dictate of woody plants in the Pike’s Peak
region. Colo. Co i. Publ., Science Series 12: no. 6; pp. 137-170. 1909-
21. ————,, The succession ot plant life on the gravel slides in the vicinity of
ae $ Peak. Colo. Coll. Publ., Science Series 12: no. 8; pp. 289-311:
1917] VESTAL—FOOTHILLS VEGETATION 385
22.
SHANTZ, H. L., A study of the vegetation of the mesa region east of Pike’s
Peak: The Bouteloua formation. Bor. Gaz. 42:16-47, 179-207. 1906
23. TUCKERMAN, E., List of species of lichens collected by the Wheeler Survey.
24.
Nv
wu
s)
r
U.S. Geog. Surv. 6:350, 351.
VestTAaL, A. G., Prairie vegetation of a mountain-front area in Colorado.
Bort. Gaz. 58:377—-400.
1914.
. Watson, J. R., Plant geography of north-central New Mexico. Bor. Gaz.
. WuitrorpD, H. N., The genetic development of the forests of northern
Michigan. Bor. Gas. 31: 289-325.
Igor.
. Witttams, T. A., Lichens of pe ng Hills and their distribution. Bull.
Torr. Bot. Club 20:349-355.
Youne, R. T., The forest enone of Boulder County, Colorado. Bor.
GAZ. 44:321-352. 1907.
VEGETATION OF HAWAIIAN LAVA FLOWS
VAUGHAN MAcCCAUGHEY
(WITH TWENTY-TWO FIGURES)
Introduction
This paper is a survey of the more important types of vegetation
which occur on the lava fields of the Hawaiian Archipelago and
their ecological relations. It has particular reference to the sper-
matophytes, as our taxonomic knowledge of the native land algae,
lichens, bryophytes, and pteridophytes is still in a somewhat
fragmentary and unsettled condition. The scope of the paper
is further restricted by including only the arid or xerophytic dis-
tricts where the lava flows are relatively barren. Under humid
climate the flows rapidly disintegrate into rich volcanic soil and
support a luxuriant rain forest. This paper is concerned with the
ecology of the xerophytic regions, as these have largely been
neglected in the literature of Hawaiian botany.
There is a widespread association of ideas which couples tropical
with humid conditions, due no doubt to the many semipopular
accounts of the “tropical jungle” and to the types of vegetation
usually exhibited in the northern conservatories. It requires a
distinct readjustment of perspective to realize that many tropical
regions possess large areas of extreme aridity. The Hawaiian
Archipelago, situated just within the tropics in the center of the
North Pacific Ocean, admirably illustrates this condition. Most
of the popular and semitechnical accounts of the islands have
emphasized the beautiful humid woodlands and have either ignored
or given scant attention to the vast rocky waste lands of barren
lava flow and cinder field.
It has been the writer’s privilege, during a residence of 8 years
in the islands, to have made many expeditions into these arid
regions and to have ascended all of the high mountains of the
group. This paper is an outgrowth of these trips, some of which
have occupied many weeks. In order to make clear the ecological
Botanical Gazette, vol. 64] [386
1917] MACCAUGHEY—HAWAIIAN FLORA 387
background of this lava flow vegetation, it is necessary to sketch
briefly the salient features of the Hawaiian volcanic mountains.
Detailed accounts may be found in such standard works as those
of Hircucock, BricHam, DANA, and Dutton.
It will be noted that the present paper deals largely with the
ecological conditions under which the lava flow vegetation exists.
A comprehensive annotated list of the lava flow plants is now
appearing in the Journal of The Linnaean Society.
Classification of islands
From the standpoint of area occupied by lava flows, cinder
fields, and other waste lands resultant from volcanic activity, the
islands may be divided into two groups: (1) the lesser islands
(Niihau, Kauai, Oahu, Molokai, Lanai, Kahoolawe); and (2) the
greater islands (Maui and Hawaii, see figs. 1, 2). The lesser
islands are, as a whole, of much greater antiquity than Maui and
Hawaii. The erosive agencies have been at work for a much
longer time, hence the lava flows have been almost wholly turned
into soil. There are some traceable flows still existent on some
of the lesser islands, Kauai, Oahu (figs. 3, 4, 5), Molokai, and
Lanai, for example, but these are relatively non-consequential as
compared with the great stretches of lava covered country on
Hawaii and Maui. The lava waste lands, above the timber line, on
Mauna Loa alone, for example, occupy a greater area than the
entire island of Oahu, Kauai, or Molokai. Thus a discussion of
the vegetation of the Hawaiian lava flows is naturally restricted
chiefly to a consideration of the islands of Maui and Hawaii, the
largest and youngest end of the long archipelago. No account
is given in this paper of the tiny islands which are strewn over a
long axis for 1800 miles to the westward of the larger, inhabited
islands. Some of these are volcanic rocks, but the majority are
tiny reefs and shoals.t Their total area is only 6 sq. miles. All are
highly xerophytic.
IsLAND OF HAwat.—Hawaii, the largest island of the archi-
pelago (4015 sq. miles), is about the size of the state of Connecticut,
with a maximum diameter of 93 miles (fig. 2). Its area is greater
* MacCaucuey, V., The little end of Hawaii. Jour. Geography 15:23-26. 1916.
388
BOTANICAL GAZETTE [NOVEMBER
than that of all the other islands combined.
volcanic masses.
It is composed of 5
The northernmost, the Kohala Mountains, is of
extreme antiquity, deeply eroded, and probably as old as Kauai.
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Fic. 1.—Island of Hawaii, showing high mountains and principal recent lava
Mauna Kea and Hualalai, next toward the south, have become
“extinct” within comparatively recent times; a lava flow issued
from Hualalai in 1801. Mauna Kea has given no manifestations
of activity within historic times. It is the highest point within
the North Pacific Ocean.
1917] MAcCAUGHEY—HAWAIIAN FLORA 389
The two southern mountains, Mauna Loa (figs. 6, 7) and
Kilauea, are active volcanoes. Their summit craters have exhibited
spectacular activity at intermittent periods throughout historic
time, and vast lava flows have emanated from their flanks. A
large flow issued from the southern slopes of Mauna Loa in May
1916. Loa dominates the island of Hawaii and is the greatest
volcanic mountain in the world. The elevations of 5 volcanic
A
ry
wi ‘iy “re
Fic. 2.—Island of pep Mount Haleakala comprises entire eastern lobe of
island; lava flow country at summit, in caldera, and on southeastern slopes of moun-
tain; regions are largely shionbe de, with exposed lava fields, fields of cinder and ash,
cinder cones, and pit craters.
masses of Hawaii are as follows: Kohala Mountains, 5489 ft.;
Mauna Kea, 13,825 ft.; Hualalai, 8269 ft.; Mauna Loa, 13,675 ft.;
Kilauea, 4000 ft.
HALEAKALA ON Maut.—Haleakala (fig. 8) is the great mountain
that forms the entire eastern portion of the island of Maui. The
summit is 10,032 ft. above sea level. It contains a great volcanic
caldera, one of the largest in the world, 7.5 miles long by 2.5 miles
wide and over 2000 ft. deep. This mountain, often called East
Maui, is very much younger than the deeply eroded western mass.
390 BOTANICAL GAZETTE [NOVEMBER
Fic. 3.—Tufa cones and xerophytic lava fields, Oahu; open crater to right, Koko
Crater; hill beyond to left, Koko Head.
Fic. 4.—Arid headland, Maka-pu’u, Oahu, illustrating ancient lava sheets
exposed by extensive erosion; note stratification of lava flows and erosion of flows at
sea level.
1917] MACCAUGHEY—HAWAIIAN FLORA 391
Maui is a volcanic doublet made up of two masses of widely
different ages. Haleakala probably ceased activity at about the
same time as Mauna Kea. The windward, northern face of
Haleakala, like that of all the Hawaiian mountains, receives
torrential rainfall (400 inches per annum) and is densely covered
with jungle forest. The leeward, southeastern slopes are conspicu-
ously arid and barren. In its geological and botanical aspects
Haleakala is much more closely related to Kea and Loa on Hawaii
Pe
Fic. 5.—Manana or Rabbit Island, deeply eroded tufa cone, isolated as small
barren islet off windward coast of Oahu, near Maka-pu’u Point; about 2200 ft. long
and 400 ft. high, separated from main island by channel of 1 7 vegetation sparse
and stunted, no arborescent vegetation.
than to its associate West Maui. It is separated from Hawaii
by a relatively narrow channel, 26 miles wide and 1032 fathoms
deep. From the standpoint of this paper it will be considered as
one of the Kea, Loa, Hualalai family.
THE FOUR GREAT MOUNTAIN MASSES.—These four great volcanic
mountains, Haleakala, Kea, Loa, and Hualalai, closely resemble
each other in a number of important ecological particulars: (1) their
summits rise 8000-14,000 ft. above sea level and are frequently
covered with snow; (2) there is a large treeless zone on the summit
of each; this is most extensive on Loa, Kea stands next, then
392 BOTANICAL GAZETTE [NOVEMBER
Fic. 6.—Summit and upper slopes of Mauna Loa as seen from summit of Mauna
Kea; note very gentle slopes of Loa, and two cinder cones (explosive vents) in fore-
d
f Hualalai; clouds lying at elevation of
n foreground,
Fic. 7.—View of Loa from summit c
7000-8000 ft.; note xerophytic vegetation
1917] MACCAUGHEY—HAWAIIAN FLORA 393
Haleakala, and lastly Hualalai, the smallest of the four mountains;
(3) the summits are marked by volcanic vents; either an active
crater (Loa); or an extinct caldera (Haleakala); or great numbers
of cinder cones (Kea); or by innumerable pit craters and cinder
cones (Hualalai); all of these are large and tangible evidences of
the earth forces by means of which the mountains were built up
to their present height; (4) the mountains rise directly and gradu-
ally from the sea, without intervening lowlands or plateaus; (5) the
—Cinder cones on floor of Haleakala caldera; at extreme upper left are
some eae sword plants (Argyroxiphium sandwicensis var. macrocephalum).
slopes and flanks of each mountain are covered by thick blankets
of lava, cinders, and ash, which in the arid summit and leeward
regions have undergone little or no erosion; (6) each mountain
has a lower windward region which receives heavy precipitation;
this rain, amounting to several hundred inches per annum in many
localities, has caused the rapid decay of the lava flows in these
zones and has covered the flows with luxuriant rain forest; the
original flow structure is obliterated beneath heavy beds of
soil and vegetation. This paper does not include the humid
areas,
394 BOTANICAL GAZETTE [NOVEMBER
Cinder cones
The slopes and summits of all four of the great mountains are
thickly sprinkled with cinder cones (fig. 9). These vary in height
from 200 to 1000 ft., with very steep slopes of 30-40°. They are
composed of volcanic ash, cinders, scoria, and other ejecta, and
are frequently strewn with volcanic bombs and other lava blocks.
These cones are most numerous on Kea and Hualalai; they are
plentiful in the caldera of Haleakala and on the leeward slopes,
and are by no means infrequent on the broad flanks of Loa. Many
of these cones are more or less completely covered with vegetation
and are conspicuous from a dis-
a tance, serving as landmarks.
‘ PIT CRATERS.—A second
Bat 2 type of volcanic vent of distinct
¥ ecological interest is the pit
: crater (figs. 10, 11). This is
f typically a circular pit, its
ey mouth flush with the surround-
ing country, its walls vertical or
eee ty funnel-shaped, and its floor
Fic. 9.—Summit plateau of Mauna littered with volcanic débris.
Kea, showing numerous cinder cones; In diameter these pits vary from
all high mountains of Hawaii, from sea Oe Peek COs Ye a
level to summit tegions. case of the smaller ones) to
several miles in the case of the
gigantic pits of Kilauea and Loa. The pits of greatest botanical
interest are those of intermediate size, namely, 100-300 yards in
diameter and of similar depths. There are many pits so deep and
narrow that no floor is visible from the rim.
The pit craters occur indiscriminately in the rainy forest zones
and on the barren slopes and summits. In the former case they
are densely filled with trees and jungle litter; their mouths are
often hidden by vines and other vegetation, and they constitute a
serious menace to the traveler and to livestock. Those that occur
in the arid sections are of particular botanical significance, as their
steep walls prohibit invasion by cattle and goats, and the vegeta-
tion within them is unmolested. Thus they constitute botanical
MACCAUGHEY—HAWAIIAN FLORA
Fic. 10.—Floor of pit crater, close to Kilauea, fissured in mosaic manner with
remarkable eee, although nearly 40 years have passed since last eruption, there
has been practically no plant invasion in this crater, due to its unfavorable situation.
Fic. 11.—Floor and wall of pit crater close to Kilauea, largely covered with
pa-hoe- le walls covered with Metrosideros polymorpha, 10-20 ft. high
396 BOTANICAL GAZETTE [NOVEMBER
oases in otherwise barren country and may be compared with the
kipukas in the a-a flows. Many remnants of the primitive flora
are today making their ‘‘last stand” in these tiny areas where they
are protected from wild livestock, the greatest enemy of the in-
digenous vegetation. Finally, the conditions of shade and moisture
Fic. 12.—Diagram illustrating formation of kipuka in midst of lava fields.
are more likely to be favorable in the pits than on the exposed
open lava flows, and the plants in the pits exhibit more normal
growth forms than those in the open.
Kipukas.—This Hawaiian word, meaning an oval hole or
depression, is a convenient desiniating for small areas that, owing
to minor topographical irregularities, have escaped being covered
by the lava flows which surround them (fig. 12). The flow may be
1917] MacCAUGHEY—HAWAIIAN FLORA 397
split or deflected so that these small patches of forest remain
unscathed. Like the pit crater, the kipuka is often a botanical
garden in the midst of an arid waste land.
The lava which surrounds the kipuka, and which may be 15-
30 ft. higher than the floor of the latter, serves as a protection from
wild cattle and goats. The kipukas frequently contain a very
rich flora, a remnant of the original forest cover. These patches
are usually of very limited area, not more than 2 or 3 acres, and
are sharply limited by the impinging lava beds. The soil within
the area is usually deep, black, and rich, and of great antiquity.
There are hundreds of these kipukas on the lower slopes of the
great Hawaiian volcanoes, but only those in the arid regions retain
their individuality. Those in the humid regions are hidden under
the rain forest.
Puu Waa-waa.—An ancient cone of minor topographical
importance, but of extreme interest from the standpoint of the
geological and botanical history of the archipelago, is Puu Waa-
waa, in North Kona, Hawaii. This cone is about 6 miles north
of the summit of Hualalai, near the Loa flow of 1859. Its elevation
is about 3300 ft..above sea level. It is 500 ft. high, with steep,
deeply fluted sides. The numerous erosion ravines which radiate
from the summit and produce this corrugated appearance (the
native name means “fluted hill’) are 50-75 ft. deep. The cone.
is composed of volcanic ash and cinders, and exhibits the quaqua-
versal structure of the typical explosive cone. It has been deeply
encircled by lava streams from Hualalai and Loa.
Studies by Cross? of the lavas which underlie Puu Waa-waa
have demonstrated that these lavas are trachytic, and vastly
older than the basaltic lavas which now largely cover them. is
hill is undoubtedly a vestige of an ancient island mass now sub-
merged beneath newer lava. Botanical explorations by Rock
have strikingly confirmed the antiquity of the Puu Waa-waa
region as contrasted with the much younger regions which sur-
round it. Many evidences of a primitive flora have been found, a
flora that has largely disappeared from other portions of this
? Cross, Wartman, An occurrence of trachyte on the island of Hawaii. Jour.
Geol. 12:510-523. 1904. :
398 BOTANICAL GAZETTE [NOVEMBER
island. The Puu Waa-waa region, like some of the pit craters and
kipukas, is a botanical oasis in the midst of a desert and harbors
much material of unquestionable antiquity.
VOLCANIC DusT.—In order to treat comprehensively the ecologi-
cal aspects of the lava regions, it is necessary to include a statement
concerning volcanic dust (fig. 13). The Hawaiian volcanoes have
Fic. 13.—Pumice fields, Kilauea volcano; chief plants, Metrosideros polymorpha
and various xerophytic species; white patches in foreground, lichens; in distance, to
right, is ohia forest, Metrosideros polymorpha.
been conspicuously quiescent in their activities during historic
times; the outpourings of lava have been relatively gentle and
non-explosive. There is much evidence, however, which indicates
tremendous explosive eruptions at various periods in the history
of the volcanoes, and at least one of these (Kilauea, 1790) has
fallen within historic times.
Among the most abundant of the varied products of these
explosive eruptions, in the Hawaiian Islands as in the case of vol-
canoes generally, is volcanic dust. Extensive deposits of dust
1917] MACCAUGHEY—HAWAIIAN FLORA 399
occur on the leeward slopes of Haleakala and in the caldera itself;
on the leeward slopes of Kea and Loa; and great beds to the
leeward of Kilauea. Perhaps the largest area is in the Ka-u
district, where, according to Hircucock,’ it covers “an area of
300 sq. mi.”’ It is not within the province of this paper to enter
into any detailed account of these dust deposits, but two important
floristic relations may be enumerated: (1) the obliteration of any
vegetation that may have occupied the region previous to the
deposit; (2) the thick layer of ashes, if rainfall or irrigation be
sufficient, forms a rich and mellow soil and transforms what would
otherwise have been lava waste land into productive country.
The plantations and ranch lands of Ka-u owe their origin to this.
It may be pointed out, in conclusion, that similar deposits of
volcanic ash, of great area and thickness, occur in Central America,
Mexico, the Sierra Nevadas, the Great Basin, Utah, Montana,
South Dakota, Nebraska, Kansas, Washington, Oregon, Alaska,
Canada, and many other places.
Ecological factors
SLoPpE.—There is considerable variation in the gradient of the
various high mountains, but on the whole it is remarkably gentle.
Loa has a deceptively gentle slope, averaging 4-6° and not over
8° at the steeper places. Its outline against the sky is that of a
very much flattened dome, or “whaleback.”’ The slopes of Kea
and Haleakala are more abrupt, usually about 12°, but sometimes
as high as 15°. Hualalai is the steepest of the 4 mountains, par-
ticularly near its summit, with an average slope of 14-18°. The
cinder and ash cones have slopes which lie at the critical angle
for material of this character, namely, 30 or 40°. The mountains
are all relatively young and have not been carved by deep, pre-
cipitous-walled amphitheaters of erosion, as have the mountains
of Kauai, Oahu, eastern Molokai, and West Maui.
PRECIPITATION.—The only comprehensive records of rainfall
in the Hawaiian Islands are those made by the United States
Weather Bureau and the United States Hydrographic Survey.
The records of the former are collaborated from the reports of
3 Hircucock, C. H., Volcanoes of the Hawaiian Islands, p. 153-
400 BOTANICAL GAZETTE [NOVEMBER
about 50 observers, scattered at various points on the islands.
As these observers are stationed in or near human settlements,
and as these settlements are situated in regions of at least moderate
rainfall, it happens that there are no records covering the areas
which form the central theme of this paper. The great upper
slopes of Loa, Kea, Hualalai, and Haleakala, having a total area
much greater than that of the peripheral lowlands, are uninhabited
waste lands and without meteorological data comparable to that
of the agricultural. lowlands.
The Hydrographic Survey, interested primarily in the rain
sections and the streams, has naturally avoided the great arid and
streamless areas which are considered in this paper. Hence it is
not possible to present extensive tables showing accurately the
precipitations on these arid districts.
It is necessary to emphasize the importance of the trade winds
as the rain-bearing winds of the islands. These winds blow from
the northeast almost continuously through a large portion of the
year. The main axis of the archipelago lies from northwest to
southeast, so that the islands lie across the path of the trades, and
hence develop strongly differentiated windward and leeward
climates. The warm trades sweep across vast stretches of ocean
before reaching the islands, and are consequently saturated with
moisture. Upon striking the cool mountain slopes very heavy
precipitation ensues, often totaling several hundred inches.* In
this zone the luxuriant rain forest reaches its finest development.
The leeward slopes, however, are robbed of this torrential rain;
the winds that reach them are usually dry and parched, and the
climate is arid or semiarid.
SNoW AND IcE.—The high mountains of Maui and Hawaii are
often snow-capped. This is particularly true of Kea, literally the
“white mountain,” which is prevailingly snow-crowned from
November to March and intermittently at other seasons. At
the season of greatest snowfall the snow line often reaches down
as low as gooo ft.; at other seasons there are frequently extensive
patches of snow at the higher levels. Near the extreme summit
+The greatest annual precipitation officially recorded in the Hawaiian Islands is
561 inches, in 1916, on Waialeale, Kauai, by the Hydrographic Survey.
1917] MACCAUGHEY—HAWAIIAN FLORA 401
of Kea, at an elevation of 14,000 ft., is a small perennial pond,
Wai-a’u, about 125 ft. in diameter. This pond is situated in an
ancient crater basin and is fed by the melting snow. It is frozen
during a major part of the year, even in midsummer. Ice occurs
in the deep fissures and caverns in the neighborhood of the sum-
mits of Kea and Loa throughout the entire year, and during late
winter it is relatively abundant.
SUMMIT REGIONS.—The treeless character of the summits has
already been mentioned. The timber line is very low, indeed
, unusually low as compared with that of mountains in other parts
of the world. Hatt’s’ explanation so accurately summarizes the
local conditions that it is reproduced herewith:
Elevation has put a sharp limit to the forests on the islands of Hawaii
and Maui at from 6000 to 8000 ft. This leaves very large areas of Mauna Loa,
Mauna Kea, Hualalai, and Haleakala devoid of forest, and they have always
been so. The mountains of the other islands, being under 6000 ft., are forested
to their summits. Six to 8000 ft. is a surprisingly low timber line, considering
the favorable conditions of soil, moisture, and temperature which prevail at
that altitude in Hawaii. The sufficient reason seems to be that the species
composing the native forests are all representatives of the torrid zone, and in
these islands, which lie right at the edge of the Tropics, find their limit at the
low altitude named.
SEEPAGE.—The physical structure of the lava flow is such that
Seepage takes place with extreme rapidity, and in the typical
flow country there is absolutely no surface water. This abnormally
high percolation greatly heightens the physiological aridity of the
lava as a substratum for plant life. Both the a-a and the pa-hoe-hoe
types of lava are highly ramified with crevices, caverns of all sizes,
and long tunnels or lava “‘tubes.’’ Thus a vertical section of the
mountain would reveal a copiously spongy texture, with large
caverns sloping toward the sea. Dawna’s® account may be appro-
priately quoted in this connection:
Over the leeward sides . . . . where rains are infrequent, a black desert
everywhere prevails, and there is, with rare exceptions, only an alternation
between the smoother fields of cooled lava and the rougher districts of scoria.
Yet over the barest fields there is always a sprinkling of verdure, growing
5 Hatt, W- L., Forests of the Hawaiian Islands. 1904 (p. 16).
6 Dana, J. D., Geol. U.S. Explor. Exped. 10:1849 (pp. 159-160).
402 BOTANICAL GAZETTE [NOVEMBER
from the many crevices or cavities. Whatever showers fall on this portion of
Hawaii are at once absorbed by the cavernous rocks; and consequently through
its whole extent, south and east, there are not two permanent streamlets.
Water is to be found only in caverns; and often a journey of some miles must
be taken by the villager to supply himself for his daily consumption. All the
caverns about the lower parts of the mountains have been well explored for
this necessary of life.
There is probably no other region in the world where rainwater
disappears with greater rapidity than on the leeward slopes of
the Hawaiian Mountains. The honeycombed lava flows swallow
it up, and convey it to the sea through deep subterranean channels.
Thus the aridity of the lava country is compounded by 3 factors:
low precipitation, high evaporation, rapid percolation.
EvAPORATION.—An_ ecological factor of probably greater
importance than either precipitation or percolation is that of high
evaporation, which characterizes the Hawaiian flows, as it does
all arid regions. This very high evaporation is strongly productive
of xerophilous structures and is probably more potent than any
other single factor.
The lava flow
In order to elucidate the structural peculiarities of the lava
country as related to plant life, a brief synopsis of the formation of
a typical flow may be presented. This is adapted from Hosss’s’
account. j
The lava either quietly melts its way to the surface at the
time of outflow, or else produces one or more fissures for its egress
to the accompaniment of vigorous local earthquakes. In either
case, if the lava issues at a point far below the crater, the hydro-
static pressure causes gigantic lava fountains to arise at the point
of outflow. The fluid, incandescent rock shoots up to heights
which range from 200 to 700 ft: or more above the surface. In
the 1852 eruption of Loa a fountain of lava 1000 ft. broad rose to
a height of 700 ft. Be
ENT ol ee es BOGE. ee oe ti Fe ees 0.20
ei id Se Oe Os has ala as 0.02
TS 8 gle Meade Soap naire ae Ca ged &: 8 DORE Re ares aetciameneres Ort 0.10
soils derived from the weathering of these basaltic lavas are very
different from those common on the mainland of the United States.
Burgess? states as follows:
They are primarily basic in composition, whereas those of North America,
for example, are ac cidic.. ..The bases or framework of Hawaiian soils are the
oxides of iron and aluminum, whereas the basis of mainland soils is silica. A
glance at the following table will show these great differences better than
words can express them. These figures represent averages of large numbers of
soil analyses made by the “‘absolute” or “fusion”? method. The column
marked “Mainland soils” represents averages of soil analyses from almost
every state in the Union and from provinces in Canada. The column labelled
“Hawaiian soils” gives average figures for over 300 composite samples of soil
from the leading types on all of these islands. All of these analyses were made
here and under similar conditions.
Hawaiian soils | Mainland soils
Per cent Per cent
Basic constituents.......... 63.717 18.9
Acidic constituents......... 36.458 81.014
RG PAL. 6.55 355 anes 59.240 13.250
CAD ic Rick eee ce oe 0.698 0.830
TD sien oe ate ie a Sa weer e oO. 77%
Be eee 0.737 1.622
INA AS es Beer 1.420 2.229
The prevailing low summit temperatures have already been
noted. The annual mean temperature of Mauna Loa at the timber
line is estimated by the United States Weather Bureau as sa F,
and the summit temperature as 35°. The Bureau states “‘in the
® Rept. Haw. Sugar Planters’ Expt. Station, Honolulu. rors (p. 62).
1917] MACCAUGHEY—HAWAIIAN FLORA 409
absence of actual observations in the higher levels, a temperature
decrease of 1° F. is assumed in each 320 ft. of ascent.” The
annual mean summit temperature of Kea is given as below 30°.
It should be emphasized that very much lower temperatures than
these prevail during a considerable portion of the year, especially
at night, and are accentuated by the high winds. During the
brilliant cloudless day the black lava sheets absorb great quantities
of heat, and the aerial temperatures near the ground become very
high. At nightfall, however, a very rapid chilling of the air
ensues, and the thermometer drops in a few hours to the neigh-
borhood of freezing point. This sudden drop is familiar to all who
have ascended the high peaks. This wide diurnal range of aerial
summit temperatures is in striking contrast to the equable and
monotonously invariable temperatures of the littoral regions.
TEMPERATURES OF LAVA AND CINDER FIELDS.—Reference has
already been made to the low temperatures which prevail at the
summit regions. Another phase of this extremely interesting
ecological factor remains to be considered, namely, the compara-
tively high temperatures which characterize the lava and cinder
fields themselves during the daytime. All of these volcanic deposits
are black or very dark in color. They absorb vast quantities of
heat during the uninterrupted diurnal period of insolation. Those
who have traveled across the lava waste lands well know that by
the middle of the afternoon the surface of the rock is distressingly
hot. The surface, the rock layer immediately below it, and the
aerial layer immediately above it have temperatures much higher
than the prevailing aerial temperatures. This condition is similar
to that reported by investigators of other desert regions. Mac-
Dovucat™ notes that ‘the sandy soil around the roots of small
herbaceous plants in the Grand Canyon, Arizona, . . . . exhibited
temperatures as high as 148° F.” It is to be further noted, as
MacDoveat states (loc. cit., p. 77), that ‘‘these extreme tempera-
tures are met only by the roots of species spreading in the surface
layers of the soil.” Deep-rooted species are not so likely to be
affected.
% U.S. Weather Bureau, Hawaii Station, Ann. Rept. 1915 (p- 2).
MacDoveat, D. T., Botanical features of American deserts, p. 82.
410 BOTANICAL GAZETTE [NOVEMBER
No thermograph records are available for subterranean tempera-
tures in the Hawaiian lava flows, but such will very likely correspond
closely with the results obtained by Cannon.” In his study of
the root relations of desert plants at Tucson, an almost continuous
record was made of the soil temperatures at a depth of 15 cm. for
the 5 years 1905-1909. CANNON states:
The record shows an undulating record of which the curve crests cor-
respond to the warmest for each day, and the depressions the coldest. The
crests . . . . are remarkably uniform in height, as also the depressions are
uniform in depth. The difference between the crests and the depressions is
about 8° F., with 12° as the greatest variation. .... Owing to the lagging
of the soil temperatures, as compared with those of the air, the maximum is not
attained until about 6 P.M., and the minimum about midnight.
A careful quantitative and qualitative investigation of the root
relations of the lava inhabiting species is yet to be made, but it
_ already gives promise of yielding some valuable contributions to
our knowledge of plant ecology. To quote again from MaAc-
Doveat (loc. cit., p. 82):
It may be said, in conclusion, that the facts disclosed as to the actual
temperatures in the soil, the diurnal and seasonal change therein, lead to the
belief that the differences in temperature of the aerial and underground portions
of plants cannot fail to be of very great importance in the physical and chemical
processes upon which growth, cell-division, nutrition, and propagation depend.
The determination of the effect of differences in temperature between the roots
and aerial shoots has received but little consideration from the physiologist
and the geographer.
Plant invasion on lava flows
The rate and amount of invasion is chiefly dependent upon two
factors: (1) proximity of adjacent vegetated regions from which
invasion may take place; (2) amount of precipitation, determining
the character and abundance of invading forms. A lava flow which
cuts a path through the humid jungle forest is soon (30-50 years)
disintegrated and overgrown. A lava flow on an arid summit
slope (8000-10,000 ft.) will remain practically naked for centuries.
Between these two extreme types every intermediate stage can be
found (figs. 11, 19, 20).
2 Cannon, W. A., Root habits of desert plants, p. 20.
MACCAUGHEY—HAWAIIAN FLORA
nd G. 19.—Floor of Kilauea, composed of black, lobular, hummocky pa-hoe-hoe;
in foreground are Metrosideros polymorpha, Vaccinium reticulatum, Sadleria
lan
Sathdeliee: etc.
ny
Fic Ping poi on floor of Kilauea crater; near foot of wall; note that
floor is aihentl Bases are Sadleria cyatheoides; scrubby trees near top of
slope are M7 eee ae
412 BOTANICAL GAZETTE [NOVEMBER
In 1912 ForsBeEs™ published some preliminary observations of
plant invasion on lava flows. His principal findings, which coincide
- with the observations of the writer, may be summarized as follows:
1. Lichen flora is much more abundant on the a-a than on the
pa-hoe-hoe and develops on the former at a much earlier date than
the latter, other conditions being the same.
2. Ferns (such as Polypodium and Sadleria) and phanerogams
(such as Metrosideros and Sophora) do not establish themselves
upon the a-a until long after they have established themselves upon
the pa-hoe-hoe, other conditions being the same.
3. The species occupying a recent flow are the same as those
occupying older flows in the immediate vicinity.
4. Soil is formed on the pa-hoe-hoe at a much earlier date than
on the a-a.
5. Acacia koa, a phyllodious species adapted to semi-xerophytic
conditions, is the prevailing tree in the leeward upper forests of the
middle zone, finally establishing itself upon the ancient flows as the
dominant and final type.
Altitudinal ranges of lava flow species
Horizontal zonation with reference to altitude is strongly
developed on the slopes of the Hawaiian mountains. As one
ascends a great volcano like Loa or Kea, one finds pronounced
changes in the vegetation with every thousand feet increase in
elevation. From the standpoint of this paper the following large
zones or belts may be recognized: lowland (littoral to 1500 ft.),
lower forest (1000-2000 ft.), middle forest (1800-6000 ft.), upper
forest (6000-g000 ft.), summit (gooo-nearly 14,000 ft.). The
summits of Kauai, Oahu, Molokai, West Maui, and Kohala rise
to 4000-6000 ft. only and are very boggy. They are considered
in another paper.“ The point must be emphasized that there is a
very considerable variation in the altitudinal limitations of these
zones on the mountains of the different islands and on different
slopes of the same mountain. In some regions the upper forest
3 ForBEs, C. N., Plant invasion on lava flows. Occ. Pap. Bishop Mus. 19f2.-
™ MacCavuGHey, VAUGHAN, Vegetation of the Hawaiian summit bogs. Amer.
Bot. 22: 45-52. 1916.
1917] MACCAUGHEY—HAWAIIAN FLORA 413
may cease at 6500 it., in others the lower forest may extend almost
to sea level; the figures must all be interpreted with considerable
latitude for local deviation.
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Fic. 21.—Diagram showing altitudinal ranges of some representative plants of
lava flow country; figures indicate feet above sea level.
Upon classifying the lava flow species with reference to their
altitudinal ranges (fig. 21), it is significant to note the great number
of ranges and the fairly close adherence of each species to its range.
Three general types of range may be cited: (1) wide-ranging
species (Metrosideros polymorpha, Sophora chrysophylla, Myoporum
414 BOTANICAL GAZETTE [NOVEMBER
sandwicensis); (2) species with moderate range (Charpentiera
obovata, Daucus pusillus, Gossypium tomentosum); and (3) species
with a very narrow range (Argyroxiphium virescens., Geranium spp.,
Straussia spp.).
Xerophytic characters of lava flow plants
PuBESCENCE.—Of the 182 species listed as occurring on the
lava flows, 62, or 33 per cent, are characterized by coatings of hairy
or woolly tomentum. The pubescence may cover the under
surfaces of the leaves, the entire leaves, the young shoots, the
inflorescences, or all aerial parts of the plant. The most pro-
nounced examples of tomentose envelopment occur in the follow-
ing genera: Argyroxiphium, Gnaphalium, Chenopodium, Sida,
Gossypium, Nototrichium, Waltheria, Abutilon, Geranium, Lobelia,
and Plantago. The point must be emphasized that with many
indigenous Hawaiian plants there is exceeding variability as to
pubescence; plants of the same species from various localities will
show every gradation from perfectly glabrous to very hairy.
This variation does not give evidence of intimate association with
ecological habitat, although in a general way the glabrous forms
characterize the rain forest and the pubescent forms the more
arid situations. There are many exceptions to this rule, however,
and a very considerable proportion of the pubescence seems to
be without obvious ecological significance.
WAXY OR VISCID EXCRETIONS.—These are much less prevalent
than the pubescent or coriaceous protections. Typical instances
are Argemone mexicana, Dodonea eriocarpa, Gardenia Brighamt,
Pisonia sandwicensis, P. inermis, Plumbago zeylanica, Raillardia
spp., Sphacele hastata, Styphelia spp., Tetramolopium spp., Vac-
cinium spp., Myoporum sp.
THORNS AND PRICKLES.—A small number of the lava flow
plants are thorny or prickly; the condition characterizes intro-
duced weeds rather than the indigenous vegetation, as shown by the
following:
Prickly Thorny Total
4 I 5
iitremte so 4 5 9
¢
1917] MacCAUGHEY—HAWAIIAN FLORA 415
Acacia Farnensiana, Amaranthus spinosus, Argemone mexicana,
Caesalpinia Bonducella, Cyanea solanacea var. quercifolia, Rubus
hawatiensis, Sida spinosa, Solanum incompletum, Opuntia tuna,
Lantana camara, and Prosopis juliflora are representative plants
of this class (fig. 22).
FOLIAGE MINUTE OR SCALELIKE, or showing strong xerophilous
modification.—Acacia koa and A. koaia (phyllodia), Exocarpus
Gaudichaudii, Portulaca sclerocarpa, Silene struthioloides, and
Sityphelia spp. are examples of very small foliage. Cassytha-
jiliformis and Viscum articulatum, two parasitic plants, have
minute or vestigial leaves.
Drcimpuous HABIT.—The deciduous habit is quite rare among
Hawaiian plants, either in the rain forest or on the lava fields.
Only 3 deciduous species occur on the lava flows, namely, Erythrina
monosperma, Sapindus saponaria, and Reynoldsia sandwicensis.
DECUMBENT, STRAGGLING, OR VINELIKE HABIT.—A very large
number, nearly 60 in all, or 33 per cent, of the lava flow plants are
either habitually prostrate or decumbent, or assume these growth-
forms on the lava. Genera containing representative species of
these habits are Abutilon, Argyreia, Boerhaavia, Caesalpina, Cap-
paris, Cassia, Chenopodium, Cocculus, Embélia, Euphorbia, Fragaria,
Gossypium, Ipomoea, Lepidium, Lipochaeta, Meibomia, Mucuna,
Osteomeles, Plumbago, Portulaca, Raillardia, Ranunculus, Rubus,
Rumex, Scaevola, Sicyos, Sida, Solanum, Stenogyne, Styphelia,
Tetramolopium, Vicia, Vigna, and Wikstroemia. Compact basal
heads or rosettes are formed by such plants as Argyroxiphium
spp., Gnaphalium spp., Plantago pachyphylla, Sisyrinchiwm acre,
Sonchus, etc.
SuccULENCE.—This typical xerophytic character is relatively
uncommon in the lava flow flora. The few examples are mostly
introduced weeds, as Portulaca,Opuntia, Bryophyllum, C heno podium,
Sonchus. Lignescence, representing the other extreme of struc-
tural adaptation to aridity, is the dominant condition. -
HiGH PERCENTAGE OF LIGNEOUS FoRMS.—Upon examining a
tabular statement of the habital characters of the lava flow flora,
one is immediately impressed by the high proportion of ligneous
and semi-ligneous forms. Over 70 per cent are woody, and this
416 BOTANICAL GAZETTE [NOVEMBER
proportion would be heightened if a number of herbaceous peren-
nials with woody bases or stocks were included. This ligneous
character is not confined to the lava flow plants, however, nor is
Fic. 22.—Typical ligneous thorny species dominant in xerophytic habitats, on
lava flows and coastal plains, Acacia Farnensiana; man is standing on explosively
produced tufa strata.
1917] MAcCAUGHEY—HAWAIIAN FLORA 417
it especially typical of them. A very large proportion of the indi-
genous vegetation in the humid forests is shrubby or arborescent.
In the Hawaiian Islands woodiness is to be interpreted, not
as a xerophytic feature, but rather as a result of long continued
plant growth (in terms of the individual plant) under unfavorable
conditions. The low temperatures and excessive humidity of the
rain forest belt are probably just as unfavorable for optimum plant
growth as are the high temperatures and excessive aridity of the
lava fields. Both habitats result in the production or modification
of a large number of very lignescent, suffruticose, dwarfed, slow
growing species (tables I and II).
TABLE I
HABITAL ANALYSIS OF THE LAVA FLOW FLORA
Class | Frequent | Rare | Total
EPOCH Nace ees 48 Io 58
eS Gg oni ele 65 2 67
Herbaceous perennials 29 4 33
ANDURIE G3 25a 3 24 2 26
TABLE II
ENDEMICITY AND LIGNESCENCE OF LAVA FLOW PLANTS*
Not endemic | Total
Class Endemic
Woody throughout. . go 108
Partly woody.....-.. 28 10 38
Herbaceous......... 12 24 36
ROME ccieerveswes | 130 §2 | 182
pes. 5 bo ber vg io" oe che total lave ow Hora is tomposed of woody
and partly Lal age we
Roor sysTEMS OF LAVA FLOW PLANTS.—No comprehensive
data are available on this interesting subject. The observations
of the writer would tend to point to the comparatively deep rooted-
ness of the woody species. The aridity of the flows has already
been described. Deeply penetrating roots may be considered as
absolutely essential for the existence of perennial plants on a rocky
stratum as dry as the typical lava flow. The roots of such species
418 BOTANICAL GAZETTE [NOVEMBER
as the writer has had occasion to examine have in every case proved
to be exceptionally long as compared with the proportions of the
aerial parts. The roots run down for long distances into the fis-
sures in the flows, and often pursue the most devious courses.
The following plants exhibit this condition: Acacia koa, A. Far-
nensiana, Alphitonia excelsa, Artemisia australis, Cassia Gaudi-
chaudii, Cheirodendron Gaudichaudii, Coprosma montana, Dodonaea
eriocarpa, Erythrina monosperma, Geranium cuneatum, Gossypium —
tomentosum, Lipochaeta subcordata, Metrosideros polymorpha,
Myoporum sandwicensis, Osteomeles anthyllidifolia, Perrottetia sand-
wicensis, Psidium guayava, Reynoldsia sandwicensis, Rumex gigan-
teus, Senecio vulgaris, Sida fallax, Sophora chrysophylla, Styphelia
tametameiae, Waltheria americana, Wikstroemia spp., Xylosma
Hillebrandia.
Sclerophyllous formations
A considerable proportion of the lava vegetation may be
classified as sclerophyllous. The leaves of these species are thick
coriaceous, usually with glistening, highly reflective upper surfaces.
Antidesma, Chrysophyllum, Coprosma, Maba, Metrosdieros, Notho-
cestrum, Osmanthus, Pelea, Pisonia, Pittosporum, Pterotropia,
Sideroxylon, Styphelia, Wikstroemia, and Xylosma are genera con-
taining typical coriaceous-leaved species. It should be noted that
Hawaii does nt exhibit the extreme sclerophyllous condition, but
rather a semi-sclerophylly. For example, many species with
sclerophyllous foliage do not show noticeable dwarfing; indeed,
they may be trees of considerable stature. In the Hawaiian
Islands the sclerophyllous formations occur at the higher levels
(5000-9000 ft.), and altitude seems to be a dominant factor in their
origin and zonation.
AGE OF LAVA FLOW VEGETATION.—The vegetation of the lava
flows is largely comprised of woody, long lived species. These
acquire the aspect and habit of senility at a relatively early stage
in their life cycles. The unfavorable conditions of the environ-
‘ment stamp themselves upon the physiognomy of the individual
‘plants and of the formations as a whole. The woody species give
every evidence of great age and slow growth. Shrubs 4-6 ft.
1917] MACCAUGHEY—HAWAIIAN FLORA 419
high show ages of 30 to 4o years; trees 15-20 ft. high, ages of 50 to
7° years; and trees of 40-60 ft. high, ages of 100 to 200 years or
older. It may be stated as a general conclusion that the ligneous
plants of the lava flows, like those of other deserts, attain great
age and assume the aspect of senility at an early period in their
lives.
Fossil trees
When a lava flow rolls down the mountain slope it may, and
commonly does, meet with a grove or woodland across its path.
The varying results of the encounter may be summarized as follows:
1. The forest may be entirely consumed by the lava flow, the
trees beaten down and burned, and all trace of the grove wiped
out by the rock sheet. This usually happens if the flow is a-a
and is quite thick. There is abundant evidence on the slopes of
Loa, Kea, and Haleakala to show that hundreds of thousands of
acres of beautiful woodland have been obliterated by lava flows
within comparatively recent geological time.
2. The flow, if of the pa-hoe-hoe type and moving quite rapidly
through the grove, may only destroy the foliage, brushwood, and
lesser vegetation. The large tree trunks are resistant even to the
great heat of the flow. Moreover, the surface lava cools with such
extreme rapidity (this is a noteworthy feature of the Hawaiian
lavas) that the radiation from within is relatively slight. In this
way large trunks are coated with an envelope or shell of lava which
quickly cools and hardens, and forms a protective case, so that the
heat from adjacent liquid lava does not reach the tree. The main
mass of the lava flows on down the slope, leaving the grove spattered
and jacketed with lava. Often great blobs of lava remain clinging
to the larger limbs and festooning the summits of the saplings.
Remnants of woodlands, exhibiting these phenomena, are not
uncommon on the lee slopes of Loa. .
3. The lava flow, acting under conditions like those just de-
scribed, but moving more slowly, may ensheath the trees to a con-
siderable height, for example, 20 ft. A jacket is formed as has been
described, but the gradual incineration of the outer layer of wood
results in a space between the tree trunk and the lava jacket.
Fresh lava, under pressure, will force its way into this space, and
420 BOTANICAL GAZETTE [NOVEMBER
its heat will still further reduce the tree trunk. This process is
continued until the tree is wholly consumed and the lava has
filled the mold. The main flow passes on, leaving the lava trees
behind. The result is a lava pillar or column, 15-25 ft. high,
2-5 ft. in diameter, and often expanded or flaring at the summit,
where the trunk branched. These so-called ‘“‘petrified trees”
retain many evidences of their arboreal origin, and correspond
somewhat in their mode of formation to the petrified trees of the
west. In the Puna district, Hawaii, there are hundreds of these
lava trees in the wake of ancient pa-hoe-hoe flows.
4. The fourth type of reaction between lava flow and woodland
produces deep tubes instead of columns. The flow enters the
‘grove and fills it to a depth of perhaps 20 ft. The rapid sheathing
around the trunks of the larger trees protects them, as in the
former cases, from immediate destruction. The flow in this
instance, however, does not pass on and drain itself from the grove,
but remains and solidifies. In the course of time the trunks
decay and leave deep tubular vertical pits in the lava. The walls
of these tubes are often plainly marked with the impressions of
the bark of the trees which they once contained. The tubes are
ro in. to 5 ft. in diameter and 15-20 ft. deep. They are known as
“tree molds,’ and are abundant on some of the old lava flows,
particularly in the vicinity of Kilauea.
CoLLEcGE OF Hawatt
HoNnoLuLu
SPEGAZZINIAN MELIOLA TYPES
F. L. STEVENS
(WITH PLATES XXIV—XXVI)
Through the kindness of Dr. CARLO SPEGAZZINI, I have received
recently a number of original packages containing type specimens
of Meliola described earlier by Dr. SPEGAzzrNt. In each case the
packet bore on the outside copious penciled notes concerning the
specimen and careful, delicate drawings of the more significant
structures. This collection of types, together with the notes and
drawings in particular, are a fine commentary on the work of Dr.
SPEGAZZINI. When we remember the large volume of his descrip-
tive work and reflect that not only his types but other specimens
as well are thus thoroughly and carefully annotated and figured,
we are in a position more adequately to recognize the great indebted-
ness of mycology to him.
The drawings of the present collection have not been published,
and in view of the comparative inaccessibility of most of these
types, it is desirable that they should be made generally accessible
to students by publication.
Permission having been received from Dr. Specazzin1, Dr.
Alva Peterson has faithfully copied for me, for publication, the
most important of the drawings. Such copying was necessary,
Owing to the color of the paper upon which the originals were drawn,
and the faintness of the penciling, which prohibited direct photo-
graphic reproduction. These drawings have been compared by
me with the type material and are published herewith with such
comments as seem necessary. A permanent celloidin mount* has
been made from each specimen and, together with a fragment of
the type specimen, is deposited in the herbarium of the University
of Illinois. The original specimens have been returned to Dr.
SPEGAZZINI at La Plata, Argentine.
MELIOLA ARMATA Speg. (fig. 1).—F. Puigg., Pug. I, no. 231;
Sacc. 93415.
*STEVENS, F. L., Phytopathology 6: 367. 1916.
421] [Botanical Gazette, vol. 64
422 BOTANICAL GAZETTE [NOVEMBER
On coriaceous leaves, Myrsine (?), Apiahy, May 1888; no. 2382
(type).
The type specimen is heavily overgrown with several parasites. There
is considerable variation in the character of the mycelium, which is sometimes
straight, sometimes quite crooked. I have not been able to see the mycelial
setae around the bases of the perithecia from which this species takes it name.
MELIOLA ARGENTINA Speg. (fig. 2).—Fung. Arg., Pug. I, no. 177;
Sacc. 1:61.
On Cyperaceae, Buenos Aires, February 1880 (type).
The mycelium is very characteristic, close, dense, somewhat like M. manca,
but distinguished by its very thick mycelial setae, which are striking, being
darker and thicker than the mycelium. They are about 15 pw thick at base and
over 800» long. The capitate hyphopodia are angular, that is, not smooth or
echinulate as shown in fig. 2. The type is heavily overgrown by a Conto-
thyrium.
MELIOLA BRASILIENSIS Speg. (fig. 3).—Fung. Arg., Pug. IV,
No... 116+. Sace. 1566
On leaves of Bignoniaceae (?), Apiahy; no. 1551. (type).
The young perithecia are surrounded by an areola of- radiating hyphae.
The perithecia also possess short hairs as figured and described by Dr. SPEGAZ-
ZINI.
MELIOLA CALVA Speg. (fig. 4).—F. Puigg., Pug. I, no. 233;
Sacc. 9:414.
On Laurinaceae, Apiahy, August 1881 (type).
Heavily overgrown with “ Podosporium penicillium Speg.”’
MELIOLA CLAVATISPORA Speg. (fig. 5).—F. Puigg., Pug. 1,
no. 241; Sacc. 92422.
On leaves of Apocynaceae, Apiahy, April 1881; no. 1701 (type).
Perhaps the most striking character is in the sessile, nearly globular
capitate hyphopodia.
MELIOLA CORONATA Shee. (fig. 6).—F. Guar., Pug. I, no. 175;
Sacc. 9:428.
On Luchea divaricata, Guarapi, July 1883; no. 3847 (type).
The figure shows perithecial hairs to be more conspicuous than they
usually are.
1917] | STEVENS—MELIOLA TYPES 423
MELIOLA CRUSTACEA Speg. (fig. n- —F. Puigg., Pug. I, no. 235;
Sacc. 92413.
On Drymis, Apiahy, 1881 (type).
The mycelium forms a compact crustose colony, with the parts decidedly
more crowded even than is shown in fig. 7
MELIOLA DECIDUA Speg. (fig. 8).—F. Puigg., Pug. I, no. 240;
Sacc. 92426.
On Convolvulaceae (?), Apiahy, April 1888; no. 2344 (type).
The capitate hyphopodia are very irregularly angular.
MELIOLA DELICATULA Speg. (fig. 9).—F. Guar., Pug. II, no. 63;
Sacc. 9:415.
On Myrisinus, Sierra de Peribebuy, September 15, 1883;
no. 3985 (type).
MELIOLA ERIOPHORA Speg. (fig. o .—F. Guar., Pug. I, no. 62;
Sacc. 92413.
On Ficus ibapoy, Paraguay, tiie 1883 (type).
MELIOLA GLABRIUSCULA Speg. (fig. 11).—F. Alig. Paul., no. 35;
Sacc. 22:48.
On Photiniae (?), Agua branca, Sao Paulo (type).
MELIOLA GLEDITSCHIAE Speg. (fig. 12).—Myc. Argent. VI,
no. 1337.
On Gleditschia amorphoidis, Puerto Leon, Missiones, July 1909 ;
(type).
MELIOLA GUAREAE Speg. (fig. 13).—Myc. Argent. VI, no. 1338.
On Guarea balansa, Puerto Leon, Missiones, August 1909 (type).
MELIOLA HARIOTI Speg. (fig. 14).—F. Guar. nonn. III, no. 78;
Sacc. 11:267; Gaill. Bull. Soc. Myc. Fr. 8:186. 1892.
On Bignoniaceae, Paraguay, no. 1291 (type).
MELIOLA LEvIpOpA Speg. (fig. 15).—F. Guar. nonn., no. 77
(p. 26); Sacc. 11:264; Bull. Soc. Myc. Fr. 8:181. 1892.
On Aspidosperma quebracho, Yaguaron, Paraguay, November
1882; no. 3589 (type).
ELIOLA LUDIBUNDA Speg. (fig. 16).—F. Guar. I, no. 178;
Sacc. 9:431.
On Pilocarpus pinnatus, Paraguay, January 1882; no. 3489
(type).
424 BOTANICAL GAZETTE [NOVEMBER
MELIOLA MEGALOSPORA Speg. (fig. 17).—F. Arg., Pug. IV,
no,’ 115; Sacc: 1267.
On Jodina rhombifolia, January 1888 (type).
The very coarse hyphae are quite characteristic.
MELIOLA MELASTOMACEARUM Speg. (fig. 18).—F. Puigg., Pug. I,
no. 232; Sacc. 92414.
On Melastomaceae, no. 2485, Apiahy, May 1888 (type).
The mycelium is often less straight than might be assumed from the
figure. The oval hyphopodia are characteristic.
MELIOLA OBESA Speg. (fig. 19).—F. Guar., Pug. I, no. 179;
Sacc. 92421.
On Rutaceae, Piragu Bras, July 1883; no. 3834 (type).
MELIOLA OBESULA Speg. (fig. 20).—F. Guar. nonn., no. 75;
Sacc. 11:262.
On Rutaceae, Caa-guaza, Brazil, January 1882; no. 3585
(type).
MELIOLA PuiccARt Speg. (fig. 21) ma 3 Puigg., Pug. I, no. 228;
Sacc. 92414.
On Rubus, Apiahy, May 1888; no. 2722 (type).
MELIOLA PULCHELLA Speg. (fig. 22).—F. Puigg., Pug. I, no. 227;
Sacc. 9:414.
On Myrtaceae, Apiahy, 1881; no. 1699 (type).
MELIOLA SAPINDACEARUM (fig. 23).—F. Guar. nonn., III, no. 79;
Sacc. 11:266; Bull. Soc. Myc. Fr. 8:184. 1892.
On Saindicess. Caa-guazu, Brazil, January 1882; no. 3600.
MELIOLA SPEGAZZINIANA Wint. (fig. 24).—F. Guar., Pug. II,
no. 64; Sacc. 9:418.
On Compositae, Paraguari, March 5, 1883; no. 3751 (type).
MELIOLA SORORCULA (fig. 25).—F. Puigg., Pug. I, no. 230;
Sacc. 9:418.
On Baccharis pingrea, Apiahy, May 1886; no. 2774 (type).
MELIOLA SUBCRUSTACEA Speg. (fig. 26).—F. Puigg., Pug.
no. 236; Sacc. 93430.
Apiahy, 1888; no. 2703 (type).
MELIOLA TABERNAEMONTANAE Speg. (ig. 27).—Myc. Argent.
VI, no. 1345; Bompland Missiones.
BOTANICAL GAZETTE, LXIV PLATE XXIV
ae
af
\WY] FS
\ ‘Gg 7 SOD
STEVENS on MELIOLA
PLATE XXV
BOTANICAL GAZETTE, LXIV
6. ———,, Untersuchungen iiber die Chlorophyllkérper und die ihnen homo-
logen Gebilde. Jahrb. Wiss. Bot. 16:1-127.
ScuMiTz, FR., erties zur Kentniss der Chrotaatophoren. Jahrb. Wiss.
Bot. 15:1-175.
TIMBERLAKE, H. ss Starck formation in Hydrodictyon utriculatum. Ann.
Botany 15:619-634. root.
9. SAMANOSS, S., Hydrodictyon africanum. Bort. GAZ. 55:72-79. 1913.
Ps
go
EXPLANATION OF PLATE XXVII
The drawings were made by the aid of the camera lucida, the magnification
being X 1040. The abbreviations used are as follows: c, cytoplasm; 7, pyrenoid;
n, nucleus; p, plastid; g, starch grain; #, starch grain growing in length toward
center of plastid; /, starch grain growing broad at base; s, minute starch grain.
Fie. 1. tical section of cell showing relation of cytoplasm, nucleus,
and chromatophores, and showing ie chromatophores packed with large
Starch grains radiating from pyreno: :
Fic. 2.—Optical section of giana ca showing grains of varying width
at base.
Fic. 3. —Optical section of chromatophore showing grains of varying
lengths and grains which vary in width of base as compared with width of
outer edge.
434 BOTANICAL GAZETTE [NOVEMBER
Fic. 4.—Cross-section of chromatophore showing grains of starch in
ioe tape
G. 5.—Same as fig. 4.
he. 6.—Same a ae a
Fic. 7.—Optical section of chromatophore _—e several smaller starch
grains in periphery of plastid.
Fic. 8.—Optical section of chromatophore showing minute starch grains
in periphery of plastid, a pyrenoid of unusual extent and shape, and many
starch grains which vary greatly in shape and length.
Fic. 9.—Median longitudinal section of chromatophore chawhig several
small starch grains.
Fic. 1o.—Same as fi
. 11.—Cross-section of cell showing chromatophore in cross-section.
Fic. 12.—Same as fig. 9.
Fic. 13.—Same as fig. 9
14.—Optical section of chromatophore showing another pyrenoid
of unusual shape, and starch grains of several different lengths.
Fic. 15.—Optical section of chromatophore showing many small starch
grains near periphery of plastid, and large grains which differ in shape because
of width of bases.
Fic. 16.—Same a
15.
Fic. 17. etry section of plastid in process of division, showing pyrenoid
after it ee divided.
. 18.—Optical section of plastid in process of division before pyrenoid
has sores division.
BOTANICAL GAZETTE, LXIV PLATE XXVII
pie a . f
BOURQUIN on ZYGNEMA
BRIEFER ARTICLES
APOGAMY IN PHEGOPTERIS POLYPODIOIDES FEE,
OSMUNDA CINNAMOMEA L., O.
CLAYTONIANA L.
Apogamous embryos developed on prothallia of Phegopteris poly-
podtoides Fee, Osmunda cinnamomea L., and O. Claytoniana L. in cultures
on Prantl’s and Knop’s full solutions and certain modifications of the
Prantl’s solution. About 6 months after the spores had been sown, the
first cases of apogamy were observed in cultures of Phegopteris poly-
podioides on Prantl’s solution with NH, NO, omitted. The spores from
which the prothallia developed had been collected during the summer
from a plant growing on a lawn in Ithaca, New York. The plant did
not appear in a normal, healthy condition, doubtless owing to the
unfavorable conditions under which it was growing. After the spores
were sown upon the nutrient solutions, the cultures were placed before
an east window, where the conditions of light and temperature were
approximately the same for all. Once each week the prothallia were
transferred to fresh nutrient solutions.
The prothallia, upon which the apogamous embryos developed, were
heart-shaped and developed archegonia but no antheridia. The apoga-
mous embryo in most cases originated as a slight swelling of the arch-
egonial cushion, either on the dorsal or ventral side, at some point near
the notch or at the center of the cushion. This swelling gradually
increased until a dome-shaped cellular mass was formed, from which
the apogamous embryo developed. The parts of the embryo usually
appeared in the following order: the leaf or leaves, root, and stem.
However, in one case a root appeared before any other member. No foot
was formed. In some cases, beside leaves, proliferations, either filamen-
tous or slightly expanded at the apices, developed from the cellular mass.
October 7, 1916, two series of cultures on the Prantl’s and Knop’s full
nutrient solutions and modifications of the Prantl’s solution were made.
Fresh spores from the same plant at Ithaca, New York, as well as spores
of the same species secured through the kindness of Dr. A. H. GRAVES
from Brooklin, Maine, were used. As soon as the spores were sown upon
the nutrient solutions, one series was placed in the greenhouse in bright
light, while the other series was kept in the laboratory before an east
window. The prothallia were not transferred to fresh solutions, but
435] [Botanical Gazette, vol. 64
436 BOTANICAL GAZETTE [NOVEMBER
were allowed to remain upon the original solution on which the spores
had been sown. A luxuriant growth of algae developed in all of the
cultures, which added to the unfavorable growing conditions.
March 9g, 1917, in both series of cultures, apogamous embryos were
observed on the prothallia which developed in Knop’s full solution from
spores collected in Maine. Archegonia were developed on many of the
heart-shaped prothallia, while in some of the cultures on the smaller
prothallia antheridia were present. Some of the archegonia appeared
aborted. In most cases the apogamous embryos developed in the
manner which has previously been described. However, a few cases of
peculiar development were observed. Miulticellular hairs or outgrowths
formed at the base of the first leaf or leaves of the young sporophyte, or at
various places on it.
On one prothallium a long cylindrical outgrowth several cells in
thickness developed from the cellular mass along with the leaves of
the apogamous sporophyte. As growth proceeded, this outgrowth
broadened out into a one-celled prothallium-like structure, after which
it again assumed the cylindrical shape bearing tracheids; at its apex it
tended to return to the prothallium structure. On another prothallium
an outgrowth which had developed from the notch of the prothallium
and projected as a narrow process broadened at the apex, forming a
. Slightly notched prothallium.
The only cases of apogamy on prothallia developed from spores
collected at Ithaca, New York, occurred in the culture of Knop’s full
solution which had been kept in the laboratory. Most of the apogamous
embryos originated from cellular masses formed on the prothallia, but
on one prothallium a cylindrical outgrowth bearing tracheids developed
from the cells in the notch. At the apex of this long cylindrical process a
cellular mass was formed, from which the leaves, root, and stem of the
apogamous embryo developed.
Two series of cultures of Osmunda cinnamomea and O. Claytoniana
were made at the same time, in the same manner, and placed under the
same conditions as the cultures of Phegopteris polypodioides. Apogamous
embryos were observed March 9, 1917, on the prothallia in the following
solutions: Prantl’s full solution, Prantl’s solution with NH,NO; omitted,
and Prantl’s solution with MgSO, omitted. Some of the apogamous
embryos developed from cellular masses; others originated as cylindrical
outgrowths containing tracheids, from the notch of the prothallia, bear-
ing at their apices cellular masses which gave rise to the leaves, root,
and stem of the sporophyte. On one prothallium an apogamous sporo-
phyte formed near the notch, while at its base a lobe of the prothallium
1917] BRIEFER ARTICLES 437
developed, on which in turn occurred an apogamous embryo. In the
latter the root developed first. Only three cases of apogamy were
observed in Osmunda Claytoniana in Prantl’s solution with K,SO, omitted.
In two cases the sporophytes developed from a mass of cellular tissue,
while the third arose as an outgrowth in the notch of the prothallium.
A further study will be made of these apogamous forms.—ELizABETH
Dorotuy Wuisr, Osborn Botanical Laboratory, Yale University.
RAY TRACHEIDS IN QUERCUS ALBA
(WITH ONE FIGURE)
In the course of a recent study of the medullary rays of the Fagaceae,
the writer was impressed with the manner in which some of the fibro-
tracheids in Quercus were associated with the rays. It is very common
to find the ends of these elements procumbent on the marginal ray cells
for a considerable distance and communicating through semi-bordered
pits. This condition is so similar to that found in certain coniferous
woods that search was made in sections of oak wood at hand for tracheids
that were distinctly radial. Fig. 1 shows a marginal ray tracheid of a
uniseriate ray in normal stem wood of Quercus alba Linn. Another,
somewhat smaller, was found in a different ray in the same section.
The location is in the median late wood of the season’s growth and is
not in immediate proximity to a large vessel. So far as the writer is
aware, ray tracheids have not previously been reported in the woods of
the dicotyledons.—SamvuEL J. Recorp, Yale University.
CURRENT LITERATURE
BOOK REVIEWS
Physical chemistry and biology
McCLenpon' has performed a valuable service to biologists by organizing
the more important facts and principles of physical chemistry that have to do
with biological problems. These are stated briefly and concisely, and the
usefulness of the book is increased by clearness in definitions. Several passages
in the introduction are suggestive of helpful lines of work and interpretation.
, The following paragraph from the preface suggests the viewpoint: “The
purpose of this book is not to go far into physical chemistry, but to develop
a tool for physiological research. Lengthy discussions of debated questions
are avoided by tentatively accepting the hypothesis which fits the most facts,
until a better one appears. For further discussion of any subject the reader is
referred to the literature list and index. For facts, however, he is referred
to nature. It is not to be hoped that theories should coincide exactly with
data available at present. Even in the most exact branches of chemistry
the atomic weight determinations, for instance, do not exactly coincide with the
values calculated from the atomic numbers, and there seems to be some doubt
as to whether lead is one element or several. How much more uncertainty
there should be about physiology, where determinations are vitiated by the
great variability of the material and its physiological states.”
The book seems to be more from the biological standpoint and much better
biology that have come to the attention of the reviewer. In the introduction
the author says, “Though the problems considered in this book are physiitogis
the methods of attack are chiefly those of the physical chemist.” The book
should do much toward encouraging the kind of work and thought that is
neither distinctly chemical, in the sense of ignoring the structures and physical
environment within which the reactions must take place in organisms, nor
yet strictly biological, in the sense of ignoring any of the chemistry involved.
When the author states (p. 1) that the methods that may be applied to the
interior of living cells are at present very few and concerned chiefly with the
inorganic constituents, he is putting entirely too low an estimate on micro-
chemistry as a means of investigation. It is true that this is as yet an imperfect
— but still it is useful in a great many cases in detecting organic compounds
well as inorganic. While his statement that ‘‘modern biochemistry is
ee not yet concerned directly with the composition of normal living
* McCLENpoN, J. F., Physical chemistry of vital phenomena. For students and
investigators in the biological and medical sciences. 8vo. pp. vi+240. figs. 30-
Princeton Univ. Press. 1917.
438
1917] CURRENT LITERATURE 439
cells, but with their decomposition products and the exchange between the
cell and its surroundings,” and that from our knowledge of these “we may
speculate on the composition of the cell and the changes that go on in it during
functional activity,” represents two lines along which productive work is being
done and will continue to be done, he is leaving in the background a third line
which has also proved helpful and promises still more for the future.
We might wish that the author had given more recognition to the fact
that many plant processes are conditioned by the permeability or impermeabil-
ity of non-living plant membranes. These, however, are very minor criticisms
on a book which commends itself strongly by its many excellent features.
Among the important topics discussed in the introduction are viscosity as a
factor in igo ee phenomena, and the relation of semipermeability to
electric phenome
His pamaaey ‘ the en: membrane (p. 94) as a separate phase which
may change with the physiological condition of the cell, and of the protoplasm
as sometimes consisting of as many as four phases, in all of which partition
solubility must be considered, as well as the molecular condition of each solute
in each phase and in the bathing medium, leads him to the conclusion that “all
of these factors make the subject of cell permeability a very complex one, no
general rules without exception having been found. All we can do at present
is to collect data on the permeability of cells to various substances.”’ It is
to be hoped that this will commend itself so strongly to biologists that we shall
have a larger output of data and a smaller output of theories.
The following shortened chapter headings will suggest the general scope of
the book: electrolytic dissociation; ne Pere, eee n and hydroxy]
ion concentration; surf es, non-electrolytes,
and colloids; enzyme action; ceca and its qsnche negative osmosis;
anesthesia and narcosis; amoeboid motion, cell division and parthenogenesis;
muscular contraction; blood and other cell media.
The “chemical summary” in the appendix will be very useful. The
literature list includes over 1500 papers arranged alphabetically according to
authors. References in the text to this list facilitate more detailed study
of any desired topic. Instead of the conventional index to the text, there is
an index to this literature list —GrorcE B. Rice.
NOTES FOR STUDENTS
Taxonomic notes.—BLaAkE? has described a new Rudbeckia (R. Deamit)
from atlas closely allied to R. speciosa.
Coxer’ has published a detailed and handsomely illustrated monograph
of the Amanita group as represented in the eastern part of the United States.
2 Brake, S. F., A new Rudbeckia from Indiana. Rhodora 19:113-115. 1917.
3 Coker, W. C., The Amanitas of the eastern United States. Jour. Elisha
Mitchell Sci. Soc. 33:1-88. pls. 69. 1917.
440 BOTANICAL GAZETTE [NOVEMBER
He recognizes 7 species in Amanitopsis, although he regards the genus as
“artificial and without systematic significance,” separated from Amanita by
the absence of a single character. In Amanita, 27 species are described,
with full discussion and citation of stations; among them there are 2 new
species and 2 new varieties. The numerous plates are unusually good reproduc-
tions of fine photographs.
ARDNER,! in a first paper on new marine algae from the Pacific Coast,
describes, in collaboration with SETCHELL, 9 new species in as many genera.
Coriophyllum and Cumagloia are described as new genera.
UFFMANS has described a new species in Russula (R. ochroleucoides)
and in Stropharia (S. caesiospora) from Tennessee. They are described in
connection with a list of fungi collected in Kentucky and Tennessee during
September 1916.
Macsripe,’ in a revision of the North American species of Amsinckia,
recognizes 23 species, 6 of which are described as new. In further notes on
a new genus (Twrricula) founded on Nama Parryi Gray, also new species in
Phacelia (6) and Miltitzia, 9 new varieties, and numerous new combinations.
A new species is also published in Petalostemum, and Gilia virgata and its allies
(a group of 5 species) are discussed. In cooperation with Payson, the same
author describes new species in Arabis, Dodecatheon, Mertensia, Veronica, Cas-
tilleja (2), and Hieracium, all from Idaho; and also revises series MULTIFIDI
of Erigeron, recognizing 3 species and 7 varieties, 3 of the varieties being new.
STANDLEY,” in a monograph of the Mexican and meee — forms
of Ficus, os 41 species, 17 of which are described a
WernuaAm; in continuing his studies of the ulus "1 the American
tropics, has described Neobertiera and Blandibractea as new genera. He
also presents the genus Sipanea, recognizing 10 species and describing 6 a them
as new; also 3 new species of Cephalanthus are described.—J. M. C.
4 Garpner, N. L., New Pacific Coast marine algae. I. Univ. Cal. Publ. Bot.
6377-416. pls. 31-35. 1917.
’ Kaurrman, C. H., Tennessee and Kentucky fungi. Mycologia 9:159-166.
Igt7.
6 Macsripg, J. Francis, Contrib. Gray Herb. New Series, no. 49. pp. 79- 1917-
7SraNpDLEY, Paut C., The Mexican and Central American species of Ficus.
Contrib. U.S. Nat. Herb. 20:1-35. 1917.
§ Wernuam, H. F., Tropical American Rubiaceae. VIII. Jour. Botany 55:169-
177. IQI7.
VOLUME LXIV NUMBER 6
THE
BOTANICAL GiaverEre
DECEMBER 1917
RESIN SECRETION IN BALSAMORRHIZA SAGITTATA
ERNEST CARROLL Faust
(WITH PLATES XXVIII-XXXI AND TWO FIGURES)
Introduction
This problem was undertaken to determine the origin of the
secretory tissues and the cause of resin secretion in Balsamorrhiza
Sagitiata. The problem was suggested by Professor JosepH E.
Kirkwoop, of the State University of Montana, to whom the writer
desires to express hearty t thanks for valuable suggestions during the
progress of the study.
Among the earliest students of secretory organs and their func-
tion was MEYEN (13), who stated that “these secretion organs arise
from enlarged intercellular passages. One cannot consider them as
mere containers, in which the secretion’ is laid by, but one must
compare the containers with their contents to inner glands, and the
surrounding walls as specialized glands.’’ This writer proposed
that the excretory cells surrounding the secretory canals prepare
the balsam and then secrete it through the wall into the inter-
cellular lumen. That the process is surrounded by a sort of mystic
vagueness for MEYEN is evident from the description ‘ wonderful’?
which he applied to the process. In his work on the pine MEYEN
(14) found resin not only within the secretory passages and the
surrounding cells but throughout the entire stem.
The opinions of the earliest investigators on resin formation
were extremely diversified. KARSTEN, WIGAND, WIESNER, and
441
442 BOTANICAL GAZETTE [DECEMBER
others of their school considered resin as a destructive slime forma-
tion secreted by the cellulose wall lining the cavity, or else a starch
derivative. KArsSTEN (8) was assured of the intimate relation
between the wall and resin gum in the wall, because of the obscurity
of the cells in ordinary mounts, whereas the walls became extremely
clear when treated with alcohol or ether (p. 317). WIGAND (26)
considered resins to be entirely out of the category of secretions, for
‘“‘a secretion in our sense is only conceivable as a homogeneous
material permeable to the cell wall.”” WreSNER (24) believed the
resin masses to be a complex of resin, cellulose, granulose, tannic
acid, and “carbonated alkalies,” with the cellulose and granulose
as intermediate products.
MUELLER (15) and VAN TreEGHEM (22) were unable to find resin
in the secretory passages, believing them to be only intercellular
spaces. MUELLER was probably the first to use alkannin tincture
on dried tissues to test for resin (p. 390). Mayr (12) thought that
resin might be secreted by the cells during rapid growth.
Undoubtedly the most careful and authoritative contemporary
investigator of resin and the problem of its secretion is TSCHIRCH
(21), who has given us.a summation of the physiologico-chemical
literature of the problem, and in addition valuable evidence con-
tributed from his own studies. Tscurrcu’s investigations have
convinced him that resins and ethereal oils cannot diffuse through
membranes which are water-permeable or water-absorbent. All
such secretions, he asserts, remain where they were first laid down.
Ecological aspects
B. sagittata was first described by Nurrat (16) in 1841. The
plant is a very conspicuous feature of the landscape of the prairies
and south hill slopes of Wyoming, western Montana, and British
Columbia. Its leaves are large, auriculate, densely hairy, growing
up from the permanent rootstock in April at 3500 ft. level in west-
ern Montana. The flower stocks are plentiful. The flowers are
golden yellow with conspicuous heads. They begin to bloom about
the middle of May and continue until July, although they reach
their maximum bloom during June.. Very soon after fertilization
the flower parts wither, and by the time the seeds are mature jn
r917] FAUST—RESIN SECRETION 443
late July the flower stocks and heads are brown and dry. The
leaves remain green until the first heavy frost, when they soon
assume a crackling dryness. The plant is a xerophyte, and is com-
monly found on the flats and upland plains, being especially abun-
dant on the exposed south slopes of the hills. The writer has
observed it frequently as high as 6000 ft. and occasionally in the
subalpine areas of a still higher altitude.
Specimens of primary rootstock of graduated diameters were
dug and dry cleaned and then weighed. They were re-weighed
until constant air dry values had been secured. Tables I and II
show the results.
TABLE I
SHOWING WATER CONTENT OF PRIMARY ROOTS COLLECTED JULY 1915; COLLECTION
DESIGNATED SERIES I
Specimen | I | 2 | 3 | 4 | 5 6
Diameter i min Se 2.5 5 0 hd
Weight ty gan 3 0.221 | 1.429 | 1.250] 2.873 | 4.195 | 6.120
Air WEN so 0.088 | 0.648 | 0.585 1.505 | 2.079] 3.002
Percentage loss........... 60.69 | 54.65 | 51.45 | 47.60 | 50.44 | 50.95
Average loss of series, 52.63 per cent.
TABLE II
SHOWING WATER CONTENT OF PRIMARY ROOTS COLLECTED OCTOBER 1915; COLLECTION
DESIGNATED SERIES
Specimen | r B 2 | 3 4 5
laweter I WM) os seek cid. s 6.0 9.0 15.0
Weight in QM has oo eos CEN 2.337 | 2-762 | 3-444] 4.144 | 6.425
Pak Gly WEE Ss ro F107)" x L805 4 “2.038 | 3.477
.60 6:30 | 50. 55.70
Average loss of series, 53.60 per cent.
Tables I and II show a more uniform correspondence for water
content in October than in July, although the average water con-
tent is practically the same in both series. In general one may
conclude that the size of the root has no definite relation to its
water content. Within the slight fluctuation the water content is
directly proportional to the weight of the root. Also, the average
water content is the same at these different seasons of the year.
444 BOTANICAL GAZETTE [DECEMBER
In direct contrast to these data is the record for water content
in random soil samples taken from field areas where B. sagittata was
growing in abundance. Table III shows such sample records, with
normal and air dry weights.
TABLE III
SHOWING PERCENTAGE OF WATER IN RANDOM SAMPLES OF SOIL IN WHICH B. sagittata
GROWS
Sample I 2 3 4 5
Weight in gm........... 94.00 126.42 89.27 104. 26 TIO.02
Air dry weight.......... 79.11 103.64 77.56 9Q.12 go.03
Percentage loss......... 15.85 eO:02 2 48.37 4.89 18.18
Average loss of series, 14.46 per cent.
Table ITI shows a fluctuation of water content in the soil entirely
incommensurate with the constant water values of the rootstocks.
This may be accounted for in part by the size of the soil particles,
since they, too, are far from uniform, and such differences would
cause both a difference in weight of soil per unit mass and a con-
sequent difference in capillarity. The fact remains, however, that
the plant, irrespective of its root size, selects a relatively constant
amount of water from soils that differ noticeably in water content.
Calculations were made also to determine the percentage of
resin in air dry roots and leaves. The parts selected were first
weighed, then placed in pure ether in an air-tight compartment.
They were left in this container for a week, during which time they
were shaken frequently. This method of extraction was used after
it had been ascertained that ether was the best solvent for the resin
of this plant. At the end of this time the ether extract was poured
off, filtered, and the ether allowed to evaporate at 20° C. until a
constant weight had been secured.. For roots dug in July the per-
centage of pure resin amounted to 3.3; for roots dug in October the
percentage was 3.3; for roots dug in May, some three or four weeks
after the,new growth had begun, the percentage was 5.2. This
shows a constant resin value during the resting period and an
increased resin content for the growing period. The percentage of
resin found in the leaves was 9.8. This value was found for leaves"
1917] FAUST—RESIN SECRETION 445
selected and dried in the middle of May, the time of maximum
growth. This resin value was found after the ethereal oil had
evaporated. By the osmic acid test it was found to contain no
fatty oils. An analysis of B. terebinthacea made by Miss HERMA
T. KreLLey (19) indicated 9.76 per cent resin, 8.96 per cent of
which was removed by chloroform and 0.80 per cent by alcohol.
In addition to this there were 5.70 per cent oils, 0.42 per cent
_volatile oils, and 5.28 per cent of fixed oils. Lioyp (11) has cal-
culated the percentage of resin for Parthenium argentatum, the
guayule of the Mexican desert. His values are as follows:
Per cent resin
PU ek ea ee 2.46
Wood growth of 1907............... a S96
Cortex of ese WOO is ceed re oe an
Growth Gt thon. or cee nde 2a 7.56
New growth i 1909 with lekies eae a 2.70
Rata AG Ce ke ey ee .. 10.80
These values were obtained from irrigated plants. WHITTEL-
SEY (25) secured from ro to 17 per cent of resin for the field plants
of the same species. If the field records are taken, it is evident that
by weight the resin content of B. sagittata is smaller than that of the
related species, B. terebinthacea, or of Parthenium argentatum.
Associated with B. sagittata in a parasitic way is a certain fly of
the Typetenid group of the family Muscidae. A complete descrip-
tion of this fly will appear in a separate paper now in preparation
by the author. The fly is found in the receptacle of the maturing
flower head, living there during the grub and pupal stages of its
development. The grub is about 1.8 mm. in length by 0.15 mm.
diameter, while the pupa averages 1.5 byo.15 mm. Usually there
is only one individual to the receptacle, but certain receptacles have
been observed by the writer in which 5 or 6 of the parasites
lived. The grub is very insidious, ordinarily boring a labyrinthine
course through the upper parts of the receptacle and into the
bases of the maturing seeds. The result is a twofold injury to
the seed: an actual destruction of the maturing seed and a stunt-
ing of growth in the seed by intercepting the course of nutrition in
the receptacle.
,
446 BOTANICAL GAZETTE | [DECEMBER
Two other important parasites on B. sagitiata are a nematode
and an acarinid. The former is found in the young stem bud before
it appears above the ground. The worm eats its way through the
bud, mostly in epidermal and cortical tissues, leaving a dry decay
behind. Undoubtedly this does much to sap the. vitality of the
developing vegetative parts, if not entirely forestalling growth.
The mite is found in the sinuses between the leaves, sucking out the
juices at the bases of the new leaves. Several hundred were found
at times in a single leaf bud. This parasite, too, undoubtedly
causes serious damage to the plant and serves to control its abun-
dance.
Collection and preservation of material
The material on which this study is based was collected from
July to November 1915 and from April to June 1916. Certain
roots, stems, and leaf buds were examined fresh, just after collec-
tion. Freehand sections were made and observations taken from
water mounts. Other material was allowed to dry and was _
examined as such. However, the greatest part of the material was
fixed in various fluids and preserved in alcohol for more detailed
examination. Of this last group, material fixed in acid alcohol and
preserved in 70 per cent alcohol gave the most satisfactory results.
Certain seedlings germinated in the laboratory, illustrating onto-
genetic growth, were fixed in Carnoy’s fluid. In addition to free-
hand sections of the alcoholic material, sections of typical roots
were made 12 u thick in series and similar series of the stem and
peduncle 8 uw thick. Sections of seedlings were cut 8 u thick.
Various stains were tried, but the most satisfactory combination
was acid fuchsin with malachite green counterstain. This combi-
nation gave an excellent contrast, since the lignified hadrome and
sclerome elements, as well as suberized walls of the Casparian strip,
took on a copper green against the fuchsin background. The ordi-
nary resin stains, cupric acetate and alkannin tincture, were made
use of throughout the study. The alkannin was found extremely
satisfactory, since it was both specific and rapid. Osmic acid fumes
(osmic anhydride) were used to test for fats. Iodine in potassium
iodide was employed for starch testing. Chloriodide of zinc was
1917] FAUST—RESIN SECRETION 447
used to determine the character of the Casparian strip. Slow alco-
holic penetration into inulin-testing areas caused a precipitate of
this polysaccharide in the shape of sphero-crystals and rhombo-
spheres, while a more rapid penetration caused the material to be
precipitated in granular and amorphous masses. Resene was
tested for im situ by the Mach and Salkowsky-Hesse cholesterol
methods (somewhat modified to suit the immediate needs). Crys-
tals of resene found in certain cells were positive to these tests.
Similar crystals were found as a check in steam-distilled resene,
dissolved in alcohol, and allowed to crystallize as the alcohol evapo-
rated. A more complete discussion of these tests will be found
under tests for resene.
The probability of error in resin tests is due in general not to a
lack of a specific reagent, but to errors in location of the substance.
Due to its solubility in high grades of alcohol it is not impossible
that it might become translocated by alcoholic diffusion. Due to
its viscous nature it might readily be dislocated in cutting sections
from fresh or alcoholic material. The data of certain investigators,
among whom are MUELLER (15) and VAN TIEGHEM (22), show no
resin in the resin canals, while Santo (18) and TscHtrcH (21) were
unable to find the secretion outside of the canals. Errors in tech-
nique must have been responsible for this. TscurrcH considered
ordinary methods of technique inadequate for the elimination of
the error and made use of a method adapted from MUELLER (loc.
cit. p. 390). He dried the material at 100° C. for some time before
cutting. He then stained with alkannin tincture in water (2 parts
of the tincture and 5 parts of water). The former procedure
allowed all volatile oils to be driven off and hardened the resin to
a tough gummy consistency, so that it was not easily removed from
its original position by the section cutter. The latter diluted the
tincture so that the resin would not readily dissolve in the alcohol.
By this method Tscutrcu was able to demonstrate resin in the
form of a dense slime in the canals of Imperatoria Ostruthium,
Arnica montana, and in the leaves of Abies pectinata and A. Nor-
manni; while the surrounding tissue, especially the secretory cells,
was free from resin content. The writer has given due weight to
this possible source of error, and has made many preparations from
448 ‘BOTANICAL GAZETTE [DECEMBER
live material, alcoholic, and dried preparations. It is only by a
study of all these preparations that he feels able to present authori-
tative data.
Germination tests
The seeds of B. sagitiata are ripe about the first week of July.
From that time they soon become dislodged from the receptacle and
fall to the ground. Between July 6 and July 15, 1915, several
thousand seeds were collected and sorted into two tentative groups,
those considered viable and those considered non-viable. ‘The latter
group comprised about 90 per cent of the whole. Of this non-viable
group almost half were eaten at the base of the seed by the Typetenid
parasite, and the remainder were small and shriveled, due to lack
of nourishment. This non-viable group was discarded. Of the
seeds saved, 100 choice ones were selected October 19, 1915, and .
weighed. Their total net weight was 1.041 gm. They were then
soaked in concentrated sulphuric acid for 8 minutes, carefully
rinsed in distilled water several times, and placed in a sterile moist
chamber at about 30° C. during the test. The record is as follows:
SERIES I
October 19; I00 ti ein: seeds weighed, sterilized, and set to germinate
in sterile moist c
November 3; one oe aid beginning to burst testa; hypocotyl protruding.
November 5; 3 seeds burst testa; hypocotyl of one 11 mm. long.
November 6; 13 seeds found soft and decaying; thrown out.
November 10; 11 seeds found soft and discarded.
November 11; 5 seeds germinating; 4 thrown off testa.
November 12; 12 seeds found soft and thrown out.
November 14; 8 seeds germinating.
November 17; mold developing; those seeds not yet germinating but con-
sidered sound rinsed in weak formalin solution, then thoroughly rinsed in dis-
tilled water.
November 28; ro seeds germinating; 5 of these fixed in Carnoy’s fluid,
5 transferred to cork supports in beakers of water and allowed to continue
growth; all ungerminated seeds discarded
Later, no further growth
SERIES It
November 18; 100 seeds selected, soaked in sulphuric acid for 5 minutes,
thoroughly rinsed, and set to germinate between damp filter paper in chamber
as in Series I; average temperature 30° C
1917] FAUST—RESIN SECRETION . 449
November 28; mold developing; seeds rinsed in formalin solution, rinsed
in distilled water, and returned to damp chamber.
December 1; culture found dry; had been dry about two hours.
No germination in this series.
SERIES III
January 25; 100 seeds selected, soaked in sulphuric acid, thoroughly
rinsed in distilled water, then placed in sterile moist chamber between filter
paper; distilled water supplied as needed drop by drop by siphon apparatus;
temperature 25° C,
January 31; first seed bursts testa; no mold.
February 1; 5 seeds found soft wid discarded.
February 10; 3 seeds germinating.
February 18; 4 seeds germinating.
February 24; 6 seeds germinating; no mold.
February 29; 8 seeds germinating; several of the remainder soft, discarded.
March 4; seeds dry for several hours; no subsequent germination.
An examination of these records shows certain interesting and
significant points. A comparatively small percentage of seedlings
germinated from selected seeds, due to lack of viability in appar-
ently viable seeds and to infection during the germination tests.
An extremely small percentage of seeds germinated from the total
seed production. Seriés I gave a total of 10 per cent of seeds ger-
minated from too selected seeds. Series II gave no germination,
due to desiccation antecedent to expected germination. Series III
gave an 8 per cent germination within the same time limit as Series I
(less one day), but at a lower average temperature. The average
for Series I and III is 9 per cent. A more elaborate and critical
study of the germination values for Parthenium argentatum by Ki1rxk-
Woop (9, p. 39) gave 10.8 per cent for selected seeds of that species.
Since the selected seeds comprised only about one-tenth of the
total seeds produced, an average of less than 1 per cent (0.9) is
obtained for the ratio of seeds germinated to the total of seeds pro-
duced. Although the plant is a perennial, the severity of the
winters in the exposed places where the plant grows kills out many
of the rootstocks. Taking into consideration the infection of the
bud and the stem by nematodes and mites, an enormous seed pro- —
duction would seem necessary to maintain the plant as the domi-
nant member of the society in which it grows.
450° BOTANICAL GAZETTE [DECEMBER
'A survey of field plants was made during May 1916. Plots
covering areas 300 ft. square were studied, and the number of root-
stocks counted and the seedlings in those areas listed. For two
such plots about 800 plants were found, equally divided between
the two plots. This number comprised all plants of B. sagittata of
all sizes and ages within the plots. An accurate idea of the distri-
bution of the plants is seen in text fig. 1. Areas 4 ft. in radius were
Fic. 1—Field of Balsamorrhiza sagittata in vicinity of Missoula, Montana, in
May 1916.
closely inspected around each plant, the plants receiving numbers as
the listing progressed. In plot 1, in the count of the first 100
plants, one seedling each was found for numbers 2, 3, 4, 8, and 100,
no other plant having the seedling within this radius. In plot 2,
for the first 100 plants counted, numbers 11, 49, 69, and 70 had
one seedling each, while number 68 had two. In a second 100 in
plot 2, numbers 41, 61, and g1 had one seedling each. Of those
plants observed about half had borne seeds the previous year, Or
1917] FAUST—RESIN SECRETION 451
about 200 per plot of 300 square ft. had been seed producers. Yet
only 5 seedlings were found in the count in plot 1, only 6 in the
first count in plot 2, and only 3 in the second count in plot 2, aver-
aging 4.66 per cent, a much lower average secured than for seeds
germinated indoors. It is evident from the dominance of this
species in the society in which it lives that it depends largely upon
the continued growth from the rootstock from year to year for
maintenance of its dominance. It is not unusual for the individual
rootstock to produce 100-300 seeds. This would more than replace
the plant each year if the laboratory germination test were effective
in the field, but the lower germination record for field plants indi-
cated beyond a doubt that the plant could not be replaced each
year by the new seedlings.
The germination in the field is comparatively late. The first
of the consocies to germinate is the seed of Lupinus ornatus, which
begins about March 1. Since B. sagittata does not fruit until the
third or fourth year, but gives up all the time and energy the first
two years to growth and food storage, it is evident that early ger-
mination is not essential to the best interests of the plant; yet the
blooming rootstocks of B. sagitatta are in flower long before the
lupine.
Of the factors determining germination, air (oxygen) is un-
doubtedly the most important. A test of this factor was made in
a group of seeds not included in the series just cited. The same
conditions prevailed in this series as in the recorded series, except
that they were covered with a sterile crystallizing dish so as to
exclude air. There was no germination. A careful comparison
with the recorded series seems to indicate that oxygen is more
necessary to prevent fungous growth than as a factor in the meta-
bolic processes of germination per se. When seeds are once set to
germinate, moisture is constantly necessary for germination, as
indicated in Series II and III.
The temperature coefficient of germination is interesting. It
is evident that germination is more rapid at first at 30° than at
a lower temperature. However, although germination at 25° is
slower, that appears to be a more advantageous condition, since
at that point a maximum growth of the plant is effected for a
ee BOTANICAL GAZETTE [DECEMBER
minimum growth of fungus. Undoubtedly under field conditions
the temperature is constantly less than 25° C., except for a short
time during the warm afternoons. In fact, practically any night
during the germination period (middle of April to middle of May)
a freezing temperature may be recorded.
Certain seeds which actually germinated or commenced to ger-
minate had been injured in the region of the root cap or even in the
region of the meristem of the root. This was the cause of a
decreased vitality in the entire plant and was often the occasion
for rapid bacterial infection. This injury was originally due to the
Typetenid parasite in the receptacle of the flower head. Such an
injury must be a source of constant decay to germinating seeds in
wet ground.
Structure
Roor.—In the developing seedling of B. sagittata at a very early
stage, a day or so after the seedling begins to break through the
testa, certain cells begin to differentiate into protoxylem. These
occur at four angles of the root section, forming a tetragon, giving
rise to the tetrarch structure of the primary root. At first these
spiral tubes develop singly, but may later be followed by one or
two others centripetally at each angle of the tetragon (fig. 7). As
might be expected from their later origin, these secondary spiral
vessels are somewhat larger than the elementary vessels. At this
earliest differentiation of protoxylem there are no indications of
protophloem from procambium. Very soon, however, such differ-
entiation begins midway and slightly centrifugal to the line joining
the first quartet of protoxylem elements (fig. 8). The procambium
cells in this region divide tangentially, with apparent irregularity,
developing protophloem externally and at the same time inter-
mediate protoxylem internally. Such growth is represented in
figs.g and 10. These periclinal divisions continue until 4 or 5 con-
centric rows of phloem are formed and until the xylem almost com-
pletely envelops the axial plate. At this time the axial plate is
still composed of undifferentiated tissue quite irregular in contour,
strikingly similar to the stem pith of the plant. The leptome
strands are limited externally by the undulating endodermis, con-
1917] FAUST—RESIN SECRETION 453
spicuous now (fig. 10) by anticlinal suberization. The appearance
of the thickenings is knotlike or looplike along the radial walls.
The endodermis, unlike that of Parthenium argentatum, contains
“no starch grains such as commonly occur in higher plants.
The secondary xylem contains not only well defined spiral
vessels and tracheids, but vessels of intermediate type. For
instance, in fig. 11, ¢ and d with bifurcating spiral reinforcements
are not far removed from a, the true spiral type, while e more
nearly approaches the eyelet type so characteristic of the tracheids.
In the dicotyledons the usual type of axial structure is par-
enchymatous; but such is not the case in B. sagittata, for there the
wood elements soon work centripetally, crowding against the origi-
nal plate cells. The latter become sclerified, so that the plate
becomes a solid disk of vessels and sclerome. Such sclerification
begins before radial suberization of the endodermis and consider-
ably earlier than resin duct formation. The centripetal crowding
with the addition of the new xylem elements increases the actual
size of the region within the cambial ring.
The suberized endodermis serves a twofold purpose. The suber-
ization thickens the walls and allows the endodermis to act as a
. supporting girdle, and, in addition, acts as an impervious barrier
against an external translocation of food material. Russow (17)
has described two types of suberization of endodermis, that in
which the radial and one tangential walls are thickened (his ““C”’
type), and that in which the entire wall is thickened on all sides
(his “O” type). HABERLANDT (6, p. 372) suggests that such dis-
tinction is not of great mechanical importance, since variations
may occur within the same genus, such as Carex, Smilax, etc.
Although the ‘‘C” type is the most usual in B. sagittata, there also
occurs the “‘O”’ type, and in woody secondary roots a thickening
which may be designated as an ““H”’ type (fig. 12). In the primary
root of 5 mm. or over, the suberized endodermis is interrupted in
regions between resin canals by phloem strands which cross into the
cortex in these regions, leaving open an avenue for translocation of
materials in these special places (fig. 13, ph). The origin and
development of the resin canals will be discussed later in this
paper.
454 BOTANICAL GAZETTE [DECEMBER
In the older rootstocks of two or more years’ growth three
regions may be distinguished, a basal primary root, a median
swollen region, and two or more branched root growths above the
swelling. From the upper reaches of these proximal root branches
arise the aerial portions of the plant system. The lowest root
region is characterized by a single row of resin canals and an axial
- stele, while both of the other parts have two concentric rows of
resin canals (fig. 14). Cross rays connect these longitudinal canals
at frequent intervals. These old rootstocks are further character-
ized by lysigenous splitting of the now functionless rays, so that the
wood is split apart in almost every ray region (fig. 15, /:, 1,). This
cracking is probably caused by tension in the wood areas and a
shrinking of the cells in the near vicinity.
The subsidiary root system of B. sagittata varies from the main
system in that it is diarch in type. The protoxylem first becomes
differentiated as two groups at opposite poles, with evidence of
protophloem developing intermediately (fig. 16). By the time the
suberization of the endodermis occurs, intermediate wood elements
have developed and the axial plate is well sclerified (fig. 17). It
is not until considerably later that the resin ducts arise (fig. 18).
The root of the plant has a rather large wood area compared with
the extra-cambial portion of the root. Table IV shows that it is
practically a ratio of two to one through all stages of secondary
thickening.
TABLE IV
Number Diameter of root Ratio
Risk ke we w he aes | mm. pe
BoP gin so, ware 2 °§ 2°
Boncy ae ees 4.5 art
Bee: ease 12 8:5
ae ogre ata a! 12 at
This excess of wood tissue may be accounted for by the area
occupied by the rays extending between the wood elements. In
no. 5, with two rows of resin canals, lysigenous cracks in the ray
region occupy about half of the wood area.
While the tracheids conform to the usual type for Compositae
and the phloem cells show no unusual ‘characteristics, certain
1917] FAUST—RESIN SECRETION 455
features of the stone cells deserve special consideration. These
cells are found principally in the hypodermal region and give a
hardness to the cortex, which makes untreated material difficult to
section. They take on a vivid green with the malachite stain.
They are somewhat larger than the surrounding cortical paren-
chyma, due to their thickenings. In surface view they present a
polygonal appearance, with bluntly rounded corners (fig. 19, a—d).
A view at the edge of the cell shows circular pores which enlarge
and approach one another as they invade the center of the cell.
The center of the cell is an irregular space devoid of the sclerified
material, usually filled with ordinary parenchyma cell protoplasm.
This content fails to react to starch, oil, or resin tests. As the
canals of the cells near the lumen, they anastomose in pairs or
triplets, giving an appearance as shown in fig. 19,d. The cells have
at least one transverse diameter longer than the longitudinal (com-
pare fig. 19, c with d). This same type of stone cells also occurs in
the axial plate of old woody roots (both primary and secondary),
and in the wood of subsequent formation, although it is never found
in phloem regions. In the latter tissues it is supplanted by bast
strands (fig. 13). The stone cells usually occur in groups of five
or six.
STEM AND PEDUNCLE.—The hypocotyledonary stem contains the
tetrarch arrangement, as shown in fig. 20. The phloem is exarch
- and the xylem endarch, with protoxylem innermost. As progress
is made up the stem, the meristematic region where the bud resides
is approached, containing secondary stem, leaf, and flower structure.
At this place the four main strands each give off two anastomosing
bundle strands to the bud, while the major portion of the bundle
strands continues into the cotyledonary collar (fig. 21). Slightly
above the section diagrammed in this figure certain changes occur
in the bundle strands. These are best illustrated by a comparison
of the section shown in fig. 22 with fig. 24, a diagram of the course of
the bundles, seen longitudinally. Between levels cc and dd strands
are given off from w and x, which unite above dd to form a median
strand ~. Coincidentally laterals from y and z form the median
strand s. Similarly above the section dd, x and y, z and w, give off
subsidiary strands which anastomose in pairs to form respectively
456 BOTANICAL GAZETTE , [DECEMBER
yr and ¢. A section taken between cc and dd might show all the
way from 4 to 12 strands, depending entirely upon the exact level
of the section, and a section taken above dd might show from 6 to 8
for the same reason. Slight variations in the origin of coincident
laterals due to unequal nourishment would be shown in an odd
number of traces. Returning to figs. 20-23, diagram 22 occurs
about the level dd. Laterals from w and x have been given off to
form p, but have not yet anastomosed. A lateral from z to form s
has been separated from the parent bundle, but its mate from y is
still intact within y. Meanwhile traces from x and z have already
arisen for the formation of r and /, although their mates are still
within the main bundles w and y. Hence the actual derivations
are atypical in location, although the end results are the same, that
is, 4 median strands (9, r, s, ¢) derived from uniting limbs of the
4 original bundles (w, x,y,z). The section in fig. 23 shows a level
above dd, where laterals are being derived from ¢ and w, y and
$s, y and r, to form strands of tertiary rank, with laterals from w
and p not yet derived. Already x and z have been broken up by
a twofold bifurcation. ‘
Certain atypical traces were found in the study of the tissues of
B. sagittata at this period in its development. In one series of sec-
tions the laterals from x and # received a trace from below. Further
observation showed this trace to end blindly at a lower level. In
another series the lateral from z to s was found to give back certain
strands to z before the lateral united with its mate from y. In such
cases transverse sections alone would be difficult to use in tracing
such bundle anatomy. In older stems and in the peduncle 8-24
traces are derived, dependent on the amount of conduction required
in these parts.
Lear.—The leaf type of a-seedling is defined with reference to
the number of traces in the blade which appear as separate entities
at the origin of the leaf blade from the petiole. In his studies on
some 50 seedlings of representative groups of Compositae LEE (10)
has chosen Silphium perfoliatum as the type for Heliantheae, to
which tribe B. sagittata belongs. The general superficial appear-
ance of S. perfoliatum and the plant under consideration is very
similar. Both seedlings are large and hardy, with no secondary
1917] FAUST—RESIN SECRETION 457
roots up to this period of development. In writing about the
bundle strands of this type LEE states as follows:
As usual in this order the single vascular bundle at the apex of the coty-
ledon first divides into 3, after which, in correspondence with the large size of
the cotyledons, each main strand gives off a large number of smaller bundles.
At a lower level, these begin to re-fuse with the larger strands, and at the base
of each cotyledon only 5 vascular strands remain, a large-median one and two
smaller laterals on either side. In the pronounced cotyledonary tube the
extreme lateral and smallest bundles fuse with the corresponding bundles from
the other cotyledon, and the composite structure produced, after decreasing
in size, moves around and joins on to one of the remaining strands. At a still
lower level in the cotyledonary tube, the remaining lateral bundles fuse in
pairs, so that 4 canal vascular strands enter the hypocotyl.
Upon examination of seedlings of B. sagittata it is evident that
neither the cotyledons (figs. 22-24) nor the first true leaf (fig. 6)
possess bundle traces exactly corresponding to the type for the
Heliantheae. There are considerably more than 5 strands for the
region above the origin of the blade (fig. 23), but at a level just
below the cotyledons in the cotyledonary collar (fig. 24, level dd)
only 6 strands are found, ‘although in certain sections even below
this level (fig. 22) a greater number is indicated, due to peculiarities
of transverse anastomoses. Even the true leaf (fig. 6) shows only
3 bundle strands at the origin of the blade from the petiole. It may
be said, therefore, that for B. sagittata we have a type of bundle
anatomy of somewhat fewer strands than for Silphium perfoliatum.
With these exceptions it has a general resemblance to the tetrarch
anatomy of the Heliantheae.
RESINIFEROUS DUCTs.—A root of a young seedling with coty-
ledons not yet outspread shows clearly the resin secretion from the
protoxylem outward through the cortex. There are large drops of
resin at the time the endodermis begins to take on suberized thick-
enings, yet at this stage no resin ducts have formed. Not until the
seedling is somé 60 days old do the ducts begin to form in the root.
The development, although surely determinetl beforehand, does not
occur until after resin formation. The method of development is
schizogenous. First a periclinal division occurs in the endodermal
cell opposite a group of tracheids. This is followed by an anticlinal
division, so that 4 cells arise from the original endodermal cell
458 BOTANICAL GAZETTE [DECEMBER
(fig. 26). A lumen develops in the midst of the 4 cells, which canal
becomes the cavity for resin secretion. Usually the 4 cells now
divide obliquely with new planes of division parallel to the walls of
the duct, so that the duct becomes lined with 2 layers of cells
(figs. 27, 28). A consequent cleavage at right angles to the walls
of the duct gives rise to 8 cells immediately lining the duct (figs. 29,
30). This ring of ducts in the cortex, just outside the endo-
dermis, is the usual complement of ducts for the root. As the root
grows, however, room is made between the older ducts and new ones
are formed. The resin ducts of the root are continuous from the
basal region to the junction of the root with the stem. These ducts
are somewhat more undulatory than are the tracheids. At times
there is evidence of the fusion of 2 ducts, but this is merely due
to a breaking down of internal processes from the cells surrounding
the lumen rather than an anastomosis.
An examination of seedlings of 2 mm. or over shows in the
hypocotyl 2 concentric series of resin canals, the outer series con-
tinuous down through the entire root system, and the inner merely
potential in the younger seedlings. The 2 series are connected by
radial canals between the longitudinal lumina of the series and by
transverse canals between consecutive longitudinal canals of the
same ring (fig. 31). Moreover, the inner series is capable of ventral
extension in roots of one year or over, so that they extend down and
around the median enlargement of the root. At this place they
all anastomose in a common center (fig. 14).
This type of concentric rings with radial anastomoses corre-
sponds to observations made by Catvert and Boop1e (2) for
Manihot Glaziovii, but is the reverse of Ltoyp’s (11) observations
on Parthenium argentatum.
The ducts in the stem consist of 2 separate systems. These
systems have similar origin and structure, but different location.
One series is found in the pith opposite the wood of the bundles,
while the other series occurs in the cortex opposite the interfas-
cicular region, almost within the interstices between the phloem 0
the bundles (fig. 25). These ducts arise somewhat earlier than
those of the root and apparently are not connected with those of
the root system in any way. They are continuous throughout the
1917] FAUST—RESIN SECRETION i 459
entire stem, although they are intercepted in certain regions by
processes from the lining cells, as shown in fig. 35. The origin of
both these systems in the stem is schizogenous and follows the
Same sequence of development as outlined for the duct system of
the root. Hotm (7), working on the anatomy of Solidago odora
(pp. 252-254), quotes VAN TIEGHEM as saying that resin ducts
have only been observed in the cortex (primary) “in certain species
of Solidago, including Kleinia; otherwise these ducts are frequent
in the pith and in the secondary tissues.”’ The two series of ducts in
the stem of B. sagittata indicate a composite type of duct anatomy,
in that they supply a duct system in the primary cortex, hitherto
observed only in species of Solidago, and in addition supply the
usual system of the pith. These ducts, too, are subsequent to resin
formation in the stem.
The resin ducts of the leaf are merely upward prolongations of
the stem systems, corresponding to the bundle trace relationships
already indicated.. For each bundle in the leaf there are two canals,
one occurring on the upper side of the leaf and the other one on the
lower side opposite the hadrome elements. DEBARy (4) gave a
very complete table of the duct systems as far as they had been
worked out in his day, VILLUEMIN (23) has studied it in certain
species, and Cot (3) has added to the knowledge of the subject, but
a thorough revision of the literature needs to be made in order
to bring the knowledge up to date.
Since VAN TIEGHEM prepared his schematic outline for types
of resin duct distribution in the stems of Compositae, at least
two new types have been observed, namely, the Solidago type
described by Hotm (7) and the type represented by B. sagittata,
described in this paper. For this reason it is necessary to recon-
struct VAN TieGHEM’s scheme to include the more recent
observations.
OUTLINE KEY TO SECRETORY PASSAGES IN STEMS OF COMPOSITAE TYPES
I, Stem containing passages within bundle sheath
. Passages confined entirely to medullary region. ...Ageratum conyzoides
B. Passages both within and without bundle stran
1. Only one medullary passage for each leaf sae bundle
a) One medullary and one cortical passage
460 BOTANICAL GAZETTE [DECEMBER
i. Both passages opposite the bundle....... Solidago limonifolia
ii. Medullary passage opposite the bundle, but cortical passage
in the interstices between bundles . . Balsamorrhiza sagittata
b) One medullary and several cortical passages
Serratula centauroides
2. A group of medullary passages for each group of cortical ones
Gren Comibaet oo ie be ae arduus pycnocephalus
b) Groups in curved series................... Helianthus tuberosus
II. Passages wholly without bundle strands
A. Passages external; not walled in on inner side by endodermis or
ON ais gis i ke PG As Vane Solidago odora
B. Wall of passages partially formed by endodermis or pericycle
1. Passages single, not in grou
a) One passage in middle at outer margin of each main leaf
ORG a ee ee eee ee Senecio vulgaris
b) One passage in middle of outer margin of each main leaf
trace; in addition one passage for each single bundle in
A
MT A AP a a i ee he ster sp.
c) One passage on each side close to phloem of each main
eeied WER ee ee ee Tagetes patula
2. Passages in
a) Three to ns passages opposite outer margin of phloem and
of minin Dene oie ie Silybum marianum
Physiology of resin secretion
Numerous theories have been proposed to explain the origin of
resin and the methods of resin secretion. Among the more impor-
tant sources conceived as a basis for resin formation may be named
the following: starch, cellulose, tannic acid, phloroglucin, a hypo-
thetical glucoside, terpene, and even chlorophyll. As diversified as
are these substances, there may be at least superficial reasons for
relating resin to any one of them. However, only a deeper analysis
of the problem, following out a particular coincidence of resin and
one of these materials, will show whether the relationship is a genetic
one or not. Evidence is here presented showing certain relation-
ships of the resin secreted by B. sagittata.
The resin of this plant appears as a viscous exudation, especially
from newly dug roots. It is a light lemon color in smaller quan-
tities, but in larger amounts (ether extraction) it appears a golden
yellow. It contains a small amount of essential oil, but gives no
1917] FAUST—RESIN SECRETION 461
tests for fatty oils. In the roots of young plants (two years or
less) it is found mostly in the outer ring of canals, while in old roots
it occurs in the two concentric rings of canals, together with the
radial anastomoses.
As has previously been mentioned, the ordinary resin tests are
cupric acetate and alkannin tincture. The acetate requires several
days and imparts a brilliant emerald to the resin. The alkannin
causes the resin to take on a brilliant crimson in a very short time.
The resin may be distinguished from oils of a fatty nature by the
osmic anhydride test. The alkannin is much more soluble in the
higher grades of alcohol, but such a high concentration of the solvent
is not desirable, since it also acts as a ready solvent for the resin.
The Tscurrcu test for resin, modified from MUELLER, was used
by Tscuircu for demonstrating that resin was present in the lumina
of canals of Imperatorium Ostruthium, Arnica montana, Abies pec-
tinata, and A. Normanni. In fact, TscutrcH noted a layer of slime
among all schizogenously formed canals. The writer has made use
of this technique for testing resin in B. sagittata and Parthenium
argentatum. These preparations show resin in the canals, as
described by Tscutrcu, but in addition demonstrate resin in the
newly formed xylem, an abundance of it in rays and inner regions
of cortex, including the cells immediately surrounding the canals,
and great masses of resin in the cambium. Such dry preparations
demonstrate resin in the identical locations as the aqueous mounts
from fresh material and alcoholic material. In this wise an accurate
check has been secured on the demonstration mounts.
An analysis was then made to discover the approximate relation
of resin to other organic materials. Resins are classified according
to their reactions to four kinds of tests: resino-tannol, resene,
resiniferous oil, and resinic acid tests.
The resino-tannols are those resiniferous materials which react
to tannin tests. For example, when ferric chloride is added to a
solution of resino-tannol, iron tannate is formed as a precipitate.
Other reagents used to test this relationship are potassium bichro-
mate, lead acetate, potassium hydrate in alcoholic solution, and
nitric acid. Should any of these reagents give a positive test, an
exceedingly difficult problem would then confront the investigator.
462 BOTANICAL GAZETTE [DECEMBER
Since tannin is not a single compound, but a convenient name for
a related group of compounds, separate tests of the entire group
would then be necessary. Moreover, as Tscutrcu has pointed out
(loc. cit. 1142), such a test would not necessarily prove a genetic
relationship, since tannin might be merely a en and not
its source.
Samples of the resin (ether eetractiod) from B. sagittata were
submitted to the resino-tannol tests. All samples gave negative
test except the one where nitric acid was used as the reagent, in
which case the test was atypical. This test was so positive, how-
ever, that it served to indicate a possible relationship of another
nature. Two or three drops of the pure resin were placed in con-
centrated nitric acid. The resin globules became dark brown, with
a violent evolution of nitric oxide in the course of two minutes,
accompanied by the formation of a cellulose membrane across the
top of the solution. When heated, this membrane burned with a
warm yellow flame and heavy smoke, leaving a black char. The
odor was like that of burning celluloid. The test was then repeated
with resin dissolved in 95 per cent alcohol. The reaction was
delayed, not taking place for 5 minutes, but was accompanied by
a more violent evolution of the gas. When the test was repeated
with the resin dissolved in absolute alcohol, the test reaction did
not take place for 6 minutes, and was even more violent than on
either of the previous occasions. Such a reaction would indicate
a relationship to cellulose or other carbohydrate.
The second group of resins are called resenes. They are the
ones showing kinship to the terpenes and the fatty aldehydes. The
modified cholesterol tests are applied to these substances. Two of
the more common and specific ones are the Salkowsky-Hesse and
Mach reactions. In the Salkowsky-Hesse test 0.002-0.003 gm. of
the resin is placed in 3 cc. of chloroform and shaken with 3 cc. of
concentrated sulphuric acid. The chloroform solution is then
evaporated in a porcelain dish and the color of the residue noted.
The color differs for various known resenes, from orange through
lavender to blue, but is always a constant index for a particular
resene. Substances that are not resenes do not give such color
tests. In the Mach tests 0.003 gm. of the resin is placed in 1 Cc.
1917] FAUST—RESIN SECRETION 463
of concentrated hydrochloric acid and evaporated in a porcelain
dish and the residue washed. If the test is positive, the residue is
usually blood orange or red. Both the Salkowsky-Hesse and the
Mach tests were applied to the July and October resin of the
Balsamorrhiza. The results were negative.
As previously described, the fatty oil test is made with osmic
acid. A slide with a thin smear of the resin is inverted over a
solution of the acid or of the crystals. The fumes of the reagent
cause fatty substances to blacken. When the osmic anhydride was
applied to resin of B. sagittata, no positive test was secured, even
after prolonged application.
If resin gives an acid reaction to litmus or requires several por-
tions of one-tenth normal sodium hydrate to neutralize, it is said
to bea resinic acid. Such acids unite with ammonium hydrate and
the hydrates of the alkali metals to form unstable resinic esters.
A great number of these resinic acids are known, although their
chemical formulae have been worked out only empirically. Certain
of these acids have been distinguished by the type of ester formed
with ammonium hydrate. For example, the group to which pimar
acid belongs builds a very beautiful acid ammonium salt, while the
group to which abietic acid belongs forms with ammonium hydrate
a non-crystalline gelatinous emulsion (see TscHiRcH, Joc. cit. 519).
The resin of B. sagitiata gives a very decided acid test. It com-
bines with ammonium hydrate, potassium hydrate, and sodium
hydrate to form resinic esters. Moreover, the ammonium ester is
an emulsoid.
The evidence gained from these tests shows that the resin of
B. sagittata is a member of the resinic acid group, giving an ester
with ammonium hydrate similar to that of abietic acid, and that
it has certain relationships to carbohydrates in that it forms a nitro-
cellulose when reacted upon by nitric acid.
It was found that by a distillation of the resinic acid, either from
the gross plant structure or from ether extracted resin, in the presence
of steam, an entirely new product was formed. The substance had
a tendency to crystallize upon cooling below 25°, and gave off a
very characteristic pungent odor, sweetish, but very irritating to
the mucous membrane. The substance was white, opaque, and
464 BOTANICAL GAZETTE [DECEMBER
crystallized out of water in a very elaborate form, simulating frost
crystals. Later it was found that it crystallized as long monoclines
out of alcohol or ether. The two resene tests were applied to this
substance, with positive results in both cases.
SALKOWSKY-HESSE TEST
Sulphuric acid solution after shaking: golden yellow.
Chloroform solution before evaporation: pale yellow, nearly colorless.
Residue after evaporation of chloroform in porcelain dish: first, bright
yellow; later, rich dark brown; red brown; ending in deep violet.
No fluorescence.
MACH TEST
Color of residue from evaporation of alcoholic solution of resin with hydro-
chloric acid and ferric chloride: dark re
This resene is saturated, failing to absorb iodine, but is weakly acid.
These positive tests, together with the general physical prop-
erties of the substance, were proof that the material under analysis
was a resene, a type of fatty aldehyde. It was further discovered
that all of the resinic acid was converted into resene in the process
of steam distillation.
Two preparations of resene from steam distillation of spring
roots were made during August 1916. One of these was placed in
a glass-stoppered bottle and the other in a loosely corked vial. An
examination after 6 months showed that the former preparation
was in the original crystalline state, while the latter had been con-
verted into a lemon-colored resin, and had completely lost its
crystalline structure. This fact supports the view that the resene
had been converted into resinic acid by an oxidative process, such
as holds true for terpenes in general. This process follows the
natural method expected in the plant tissues, and is the reverse of
the reduction process in the presence of steam.
The discovery that resene is derived from resinic acid gave rise
to the inquiry as to whether resene might not be found in the
Balsamorrhiza plant; in short, whether there might not be a genetic
connection between the two substances in the plant itself. The
_ following methods were carried out in this inquiry: modified resene
tests en bloc and modified Mach tests applied microchemically.
*
1917] FAUST—RESIN SECRETION 465
In the tests en bloc equal portions of Balsamorrhiza roots (alco-
holic preservation of August material) and sprouting stem buds
(fresh March material) were each placed in 5 cc. of chloroform and
left for two days. The plant tissues were then removed and 5 cc.
of sulphuric acid added, according to the Salkowsky-Hesse method,
and the mixture thoroughly shaken. The results are given in
table V.
TABLE V
| August root | March bud
Sulphuric acid solution.................. Pale tan Colorless —
Cionotorin sobitiog 9c. cet cs < Colorless Colorless
Residue from evaporation............... Colorless Lavender to violet
MINGPRCPNES 5d oa a None Marked entices eiction
The Mach test (modified) was used on sections of rapidly grow-
ing stem buds, just previously placed in 85 per cent alcohol. Sec-
tions of this material were cut in 95 per cent alcohol; 1 cc. of this
alcohol, 1 cc. of ferric chloride, and 1 cc. of hydrochloric acid were
mixed and the sections transferred to this mixture on a depression
slide. The slide was then gently heated until the mixture was
reduced to about rcc. Even from gross inspection a typical Mach
test was produced in the vascular tissues. Examination under low
power of the microscope showed reactions in the following places:
heavy stain in the cambium and rays (identical with regions testing
heavily for resin in fall tissues); specially marked test against walls
of endodermis facing cortex; all through cortex and pith to more or
less degree. In the heavily testing regions masses of monoclinic
crystals were found, deeply impregnated with the stain from sur-
rounding crystals that had dissolved (fig. 37). This same test was
applied to roots of the August collection, preserved in 60 per cent
alcohol. The results of the test were negative. This very
specimen block had been used previously for resin tests and
had yielded a decided resin test in the vascular and conductive
areas.
These two tests, the Salkowsky-Hesse and Mach, modified to
meet the needs of the material under investigation, applied to
Balsamorrhiza material, showed a negative test for fall roots and
466 BOTANICAL GAZETTE [DECEMBER
a uniquely strong ‘positive test for the spring bud region. In
fact, a comparison of the former test with the present one would
indicate a much higher percentage of the resene in the spring bud
than was necessary for a test reaction. Moreover, the Mach test
both checked up the results obtained in the Salkowsky-Hesse re-
action and gave the precise location of the resene in the grow-
ing bud.
A final test to check up the previous determinations consisted
in placing some of the material of the fall collection and the spring
collection in absolute alcohol-ether, half and half, for a period of
two days, then allowing the filtered solution to evaporate. No
crystals were found from a careful examination of the fall roots,
yet an abundance of crystals of the monoclinic type were secured
from the spring stem material.
The evidence secured from these reactions for tissues of B. sagit-
tata shows (1) that resene is found in the growing plant tissues, in
the meristem and conductive areas; (2) that resene is found in the
same region in spring tissues where resinic acid is found in the fall
tissues; and (3) that resinic acid areas in fall tissues test negatively
for resene.
In the middle of May roots dug about May 1 were tested for
percentage of ether extract. Such data are recorded in the ecologi-
cal section of this paper. This material shows both resene and
resinic acid present in tissues at this particular time of the year,
when the leaves had been well developed and metabolic processes
were near the zenith point.
When tests were made on various parts of the plant to discover
whether a Mach test could be secured, the test was negative.
These tests were made on stem and root tissue and on cotyledons
and embryo within the seed coat. Later certain crystals were
noted in the connective and storage tissues of the plant, spheroidal
in shape, with rays arising from an eccentric umbo. The crystals
were observed in material which had been preserved in alcohol
en bloc. These crystals did not occur in fresh aqueous mounts nor
in fresh material sectioned and mounted in alcohol. The type of
the crystal was such and its reaction to reagents such as to establish
1917] FAUST—RESIN SECRETION 467
it as the crystallized inulin, a colloidal polysaccharide. In ordinary
growing tissues these crystals are deposited in a viscous lemon-
yellow mass, but in alcohol they undergo certain changes in shape.
In readily permeable tissues they are laid down as granular masses,
but where there is slow alcoholic penetration they are laid down as
sphero-crystals. Such crystals are well illustrated and their loca-
tion shown in fig. 36 (si). They are found in connective tissue,
especially in the rays and in the inner cortex. In this same speci-
men the canals are filled with resin. The semiviscous, semigranular °
resene is well brought out in fig. 16, the section of a very young
subsidiary root without secondary thickenings yet developed. In
fig. 17, the section of a subsidiary root further developed, is shown
in the more permeable outer region of the cortex the semiviscous,
semigranular inulin, while the sphero-crystals are found in the
inner cortex, not so permeable to alcohol.
Other observations on the growing stem buds showed the follow-
ing relationships. Young etiolated stem buds showed no inulin,
while green stem buds were filled with inulin. Such observations
are proof that the result of the photosynthetic process in B. sagit-
tata is inulin. Such a substitute for starch is found in the related
Compositae, Helianthus annuus, Inula Helenium, and for roots of
Dahlia spp.
As the microchemical tests progressed, evidence became
stronger that a genetic relationship existed progressively in turn
between each two of the three products found in Balsamorrhiza,
namely, inulin, resene, and resinic acid. The hypothesis built up
on this evidence may be stated thus:
Inulin>
‘6 &e'
| \
\ ~
fast,
\ ¥
TION
4
A
(SIN SECRE
JST on RE
FAU
4
PLATE XXXI
BOTANICAL GAZETTE, LXIV
VOE
ite @
iy
ada:
SG
0
[et]
En
a
HAG
LL A
Kf cE
may) OE
Ki at
¥
bs
Nene,
M4
+
:
(7
at
a
Hy
.
i
UU
S
t 36 |
2 U Ne
3
\
CMZODE
OTST
FAUST on RESIN SECRETION
1917] FAUST—RESIN SECRETION 479
ments, and sclerified stele; inulin deposits in outer cortex granular; in inner
cortex, sphero-crystals; mx, metaxylem; ph, phloem; c, cambium; sch,
sclerome; en, endodermis; hy, hypodermis; e¢, epidermis; X150.
IG. 18.—Section through old subsidiary root, showing formation of resin
canals in region of endodermis: rc, resin canals; 150.
1G. 19.—Detail of sections of stone cells: a, section at edge of cell showing
unsclerified pores; b, border of internal opening; c, d, through center of cells;
a, 6, d, longitudinal sections; c, transverse sections; 300.
IGS. 20—-23.—Sections Sf itcraile critical levels of a 2 mm. seedling: fig. 2
region of hypocotyl; fig. 21, lower cotyledonary collar; fig. 22, upper ae
donary collar; fig. 23, iver reaches of cotyledons; w, x, y, 2, primary bundle
traces in hy pocetyl: p, r, s, t, secondary bundles of cotyledonary collar; white
areas in sacs phloem; black areas, xylem; dotted areas, metaxylem; X60.
Fic. 24.—Longitudinal diagram of bundle traces in region of hypocotyl
and lower epicotyl, reduced to one plane: k, m,n, 0, primary traces of epicoty];
other designations as in figs. 20-23.
Fic. 25.—Transverse section through peduncle: 9, pith; c, cortex; 7,
resin sate of outer series; r2, resin canals of inner series; 150.
Fics. 26-30.—Cross-sections of resin canals of root at various stages of
Pe asa fig. 26, first periclinal division of initial endodermal cell; fig. 27,
first oblique division; figs. 28, 29, progressive stages in formation; fig. 30,
fully developed canal; Ca, Casparian thickening; 150
IG. 31.—Transverse section of old root (4 or 5 years), showing two series
of canals ie radial anastomoses; Xt.
Fic. 32.—Longitudinal ictal section of fully aig ty canal; X150.
PiG. | 33 et hidon? of young seedling in ese tae deel
region, showing radial a moses of two series of his canals in root system
rr, Outer series; 72, inner cue: a, radial canals.
Fic. 34. Scheneae diagram*from sections, illustrating extent and con-
nections of resin canals of 5 mm. seedling, in region of hypocotyl: r:, outer
series of canals; r2, inner series of canals; a, radial canals.
Fic. 35. 2 Section through origin of resin canals of stem: a, initial canal
cell in process of division; }, cells dividing a second time; ¢, d, subsequent
divisions to form canals; 300.
1G. 36.—Section of 3-year-old root, stained to mae distribution of inulin
and resin: si, sphero-crystals of inulin; r, 7, resin deposits.
Fic. 37.—Detailed sketch of inulin, resene, and resinic acid: a-d, wi
pith cell of stem; e, f, deposited from evaporation of alcoholic solution; a,
crystal of inulin; i; crystals of resene within cell; c, d, resene crystals im ee
in resin masses; e, detail of resene crystal; /, resene crystal imbed
masses; 150.
DISTINGUISHING CHARACTERS OF NORTH AMERICAN
SYCAMORE WOODS
WARREN D. BRUSH
(WITH PLATES XXXII-XXXVIII AND THREE FIGURES)
Native sycamores*
Four out of the five known species of sycamores (Platanus) are
natives of North America. One of these is found in the eastern —
United States, one in the southwest, one in the Pacific Coast region,
and one in Mexico. The only species in the Old World inhabits
central and southern Europe and southwestern Asia. The North
American species are the common sycamore (P. occidentalis L.),
California sycamore (P. racemosa Nutt.), Arizona sycamore
(P. Wrightii S. Wats.), and the Mexican sycamore or alamo (P.
Lindeniana Mart. and Gal.). The oriental plane tree (P.
orientalis L.) is perhaps the most widely known as well as one of
the largest trees in the temperate climate and is frequently
planted for shade in streets and parks.
Gross structure
The only sycamores considered in this paper are the three
species native to the United States: the eastern or common, the
California, and the Arizona sycamores. The woods of these native
sycamores so Closely resemble each other in general appearance that
« The name sycamore rightly belongs to a fig tree (Ficus sycomorus L.), a native
of Asia Minor. Sycamore is a combination of two Greek words, sykon, a fig, and
a mulberry. The leaves of this oriental fig tree resemble those of a mulberry
In Acntialls this name is applied also to Panax elegans F. and M. and Sterculia lurida
and M. In France the name faux sycomore is given to the China-tree (Melia
Azedarach L.). The name is ee applied in this country to sycamore maple
(Acer pseudo-platanus L.), because of a general resemblance of the leaves. Plane tree
is the generally accepted name ee the oriental Platanus orientalis, and it has been
applied to the North American P. occidentalis from early times. The names applied
locally, however, are buttonball, buttonwood, cottonwood, and water beech. Button-
ball is a suitable name because it has not been applied to any other tree, and it is
descriptive of the fruit. Sycamore is the accepted trade name and the one most
widely used
Botanical Gazette, vol. 64] [480
1917] BRUSH—SYCAMORE WOODS 481
the elements which serve as distinguishing characters must be mag-
nified, to some extent at least, for positive identification. The
chief distinguishing characters of the sycamore woods are the color
of the sapwood and heartwood and the size of the pith rays. The
average weight? and hardness of these woods differ very little, and
hence they cannot be depended upon as distinguishing characters.
Specific gravity and the weight per cu. ft. are shown in table I.
TABLE I
Species Specific gravity ve taie tock
Platanus occidentalis ce oO. 5678 35-39
Platanus Wrightii.......... 0.4736 29.51
Platanus racemosa.......... 0.488 30.41
SAPWOOD AND HEARTWOOD
While the sapwood and heartwood usually do not show distinct
limits, they are easily distinguishable from one another by their
color. The sapwood of the eastern sycamore is light brown, and
the heartwood has a decidedly reddish tinge; the sapwood of Cali-
fornia and Arizona sycamores is a yellowish white, while the heart-
wood is somewhat darker and only slightly tinged with red. In
all species the sapwood occupies only a thin zone. Both the color
and thickness of the sapwood and heartwood, however, are very
variable, depending probably to some extent upon the age, climate,
soil conditions, and the general health of the tree. Trees growing
in low or moderately wet soil usually develop thicker sapwood than
those found on higher well drained ground. As a rule the eastern
species has a thicker sapwood than the western ones.
ANNUAL RINGS OF GROWTH
Annual rings of growth in all three species (pls. XXXII-—
XXXIV, ew and Jw) are clearly visible to the unaided eye. Each
ring is defined from the next layer by a more or less distinct
a Ble ESO ry
? The Hardwood Manufacturers’ Association h
sycamore lumber to be 3200 pounds per 1000 board feet. The testi per board foot
of the western species has not been listed.
482 BOTANICAL GAZETTE [DECEMBER
tangential line made up of several rows of radially flattened wood
fibers which mark the outer boundary of the late wood. The
early wood of the next annual ring lies immediately outside of
this dense tissue, and it begins with a more or less continuous
row of pores. The portion of the ring formed in the beginning
of the year’s growth is thus considerably more porous than that
produced at the end of the season. The pores are slightly less
numerous and smaller in diameter in the late wood than in the
early wood, but they are so nearly uniform in size throughout
the annual rings of growth that with the unaided eye they do
not materially assist in defining the inner and outer boundaries of
growth rings.
The annual rings do not differ in the three sycamores except
that in the eastern species they are less clearly defined than in the
other two. The width of these annual layers of growth varies
considerably. The annual diameter increment of the eastern
species for trees of about go years of age and growing under average
soil and site conditions is approximately 0.2 in. per year. On an
average the western species grow much more slowly.
PITH RAYS
_ The numerous broad pith rays constitute the most striking
character of sycamore wood; they are conspicuous (pl. XXXII, pr )
both in the transverse and radial sections. In the distinctness of its
pith rays sycamore woods have a general resemblance to beech, the
large pith rays of the latter, however, being less numerous. The
rays of sycamore wood are very conspicuous in quarter-sawed
boards, giving the cut surface a “silver grain” effect similar to
quarter-sawed oak. In tangential or “bastard cut” boards the
pith rays are least conspicuous, although clearly visible to the
unaided eye. With the hand magnifier they appear as numerous
and evenly distributed, short, vertical lines.
As stated, the size of the pith rays is one of the chief distinguish-
ing characters of the sycamore woods. In gross structure (as
seen with the hand lens) the rays are decidedly larger and
usually darker in the common sycamore than in the other two
species.
1917] BRUSH—SYCAMORE WOODS 483
Minute structure
The pith rays are the only reliable means for identifying the
woods of the sycamores. As viewed in the tangential section, the
pith rays are broadest horizontally in the common sycamore and
narrowest in the California species; the rays are lowest vertically
in the common sycamore and highest in the California species.
The rays of the Arizona sycamore are intermediate in character.
These characters can readily be seen under the microscope.
VESSELS
The wood of the sycamores is diffuse porous, that is, the pores
or vessels are of approximately the same size and more or less evenly
distributed throughout the annual ring of growth. They are often
grouped, and together they constitute about one-half of the trans-
verse area between the pith rays. In outline these pores are
irregular and may be oval, elliptical, or nearly round; the sides
in contact with other vessels are usually much flattened. The
vessels first formed in the spring are usually compressed tangen-
tially. Average diameters were computed from 50 measurements
on each of the 3 species, and show very little variance (table II).
TABLE II
AVERAGE, MAXIMUM, AND MINIMUM DIAMETER OF VESSEL SEGMENTS OF
THE THREE SPECIES
Species | Average Maximum Minimum
Platanus occidentalis....... 0.083 mm.| o.101mm.| 0.063 mm
Platanus Wrightii.......... 0.076 0.094 0.039
Platanus racemosa......... 0.073 0.093 0.062
The vessels are thin-walled and are composed of numer-
ous short segments placed end to end. The upper and lower
ends of these segments are usually slanting, the oblique end
always facing the pith rays. In tangential or radial section
these segments are readily measured under the microscope;
table III gives averages computed from 25 measurements on
each species.
AVERAGE, MAXIMUM,
BOTANICAL GAZETTE
TABLE III
THE THREE SPECIES
[DECEMBER
AND MINIMUM LENGTHS OF VESSEL SEGMENTS OF
Species Average Maximum Minimum
Platanus occidentalis ....... °.786mm.| o.889mm.}| o.718mm
Platanus Wrightii......... ©.549 0.727 °.390
Platanus racemosa ......... 0.677 ©.749 ©. 608
WOOD FIBERS
These elements form the ground mass of sycamore wood, and
their walls are usually much thicker than those of other wood ele-
ments. The fiber length does not differ very much for the three
species. They are shortest in Platanus racemosa and longest in
P. Wrightii, but the difference is so slight that it cannot be depended
upon as a reliable distinguishing character. Table IV gives the
average lengths of 100 measurements on each species.
TABLE IV
AVERAGE, MAXIMUM, AND MINIMUM LENGTHS OF FIBERS OF THE THREE
SPECIES
é Species Average Maximum Minimum
Platanus occidentalis ....... 1.63 mm 2.02 mm. I.39 mm.
Platanus Wrightii......... 1.69 2.02 1.47
Pitas FRCEMUEE ios 2... ¥, a5 1.93 1.26
TRACHEIDS
The tracheids of sycamore wood (pls. XXXII-XXXIV, /, and
fig. 1, E) are found usually adjacent to vessels. These elements,
together with the wood parenchyma fibers, form more or less con-
tinuous irregular lines throughout the masses of wood fibers, from
which they may be distinguished by their thin walls. Tracheids
take an intermediate position in respect to size and form between
vessels and wood fibers, and in sycamore wood they often possess
characters belonging to either one or the other of these two very
dissimilar kinds of elements. About midway between these two
extreme forms (the vessel and the fiber) is the more or less fixed form,
1917] BRUSH—SYCAMORE WOODS
FED
\
Min
SS
\
p)
nn
eS
as
VAN
\
ee ys
Fic. 1.—A, vessel segment of P. occiden-
talis with se perforations (~) at both ends,
one at lower end with single bar (); 9, bor-
dered pits; sp, simple pits; <150; B, end o
vessel segment of P. occidentalis, Shows sca-
starm (laddsst¢
(ladder 150;
C, portion of vessel wall of P. Sgeelaieles
enlarged to show bordered pits on upper surface (a) and in profile
(6); X400; D, intermediate form between vessel and tracheid from
wood of P. occidentalis, showing simple perforation at lower end ()
and scalariform perforations at upper = (scp); bp, bordered pits;
SP, simple pits; 5k — oblique sim;
le pits; X150; £, tracheid
of P. Wrightii with slitlike perforations se both ends (s/p); sp, 8imple E
pits; Xr150.
ee
\
aS
& ane an \ \ ) \
\ \
atk ‘ he
oa
NNGLY ‘us
AVA
‘VARthttD
486 BOTANICAL GAZETTE [DECEMBER
the “typical tracheid” or “true tracheid.” This form, which occurs
in the wood of practically all of the broadleaf trees, is analogous
to the tracheid of the conifers. From the primitive tracheid form
there seem to have developed throughout the broadleaf tree species
two highly specialized forms, vessel and wood fiber. In the genus
Platanus the general term “‘tracheid”’ must be made to include all
transitional forms between the typical tracheid and the vessel on
the one side, and between the typical tracheid and the wood fiber
on the other side.
The typical tracheid is moderately thin-walled, has oblique
simple pits, and the perforations at the ends are slitlike (fig. 1, £).
The tracheid forms between the typical tracheid and the vessel
possess, in addition to the oblique simple pits, rows of oblique
bordered pits and transverse simple pits, both of which forms occur
in the walls of vessels (fig. 1, A and D, bp and sp); and the perfora-
tions at the ends may be simple, either with or without bars, or
scalariform, as in vessels; or the perforation may be a transitional
form between the scalariform as found in vessels and the slitlike
perforations found in true tracheids (fig. 1, D, sp). The tracheid
forms between the typical tracheid and the wood fiber are some-
what slender, pointed at both ends, and thick-walled, and possess
the vertical bordered pits of wood fibers in addition to the oblique
simple pits belonging to tracheids. They often have also small
transverse slits like those in the ends of true tracheids (fig. 2, D,
slp). These tracheid forms (or tracheids) of sycamore wood,
therefore, although extremely variable, may be defined as moder-
ately thin-walled, elongated elements with slightly oblique ellipti-
cal or slitlike simple pits and slitlike perforations at the ends.
They may also possess those pits common to either vessels or
wood fibers, and the perforation at the ends may be simple,
scalariform, or slitlike, these types often grading into each other.
The average tracheid is 1.3 mm. in length and about 0.04 mm. In
diameter.
3 A study of such transitional forms as are found in the wood of the sycamores is
of great value to the student in wood structure, in that it shows the relationship of
the elements to each other and assists in their classification and in the recognition of
the essential features belonging to each class.
1917] BRUSH—SYCAMORE WOODS 487
WOOD PARENCHYMA FIBERS
Wood parenchyma fibers, used for the storage of food materials,
are usually less than half the length of the wood fibers, are moder-
ately thin-walled, and composed of a number of individual cells.
In sycamore woods wood parenchyma fibers occur only in the
neighborhood of vessels and pith rays, from which they obtain their
food supply. Each fiber consists of 1-8 oblong or cubical cells.
Two forms of wood parenchyma fibers may be distinguished in
sycamore wood. The fibers of the first form communicate directly
with the vessels and have large transverse simple pits (fig. 2, A).
The fibers of the second form communicate with one another and
with those of the first form, but they do not communicate directly
with the vessels; these have dotlike bordered pits (fig. 2, B).
INTERMEDIATE FIBERS
Intermediate fibers, although very similar to wood fibers, also
serve for food storage. They are slightly thinner-walled and shorter
than the latter and possess many small oval oblique bordered pits.
They may be distinguished from the wood fibers, among which
they are sparsely scattered, by the starch contained in them.
They are intermediate in form and function between wood paren-
chyma fibers and wood fibers; hence the term “intermediate fiber.”
PITH RAYS
The three species of sycamore woods may be distinguished from
each other by the pith rays. The rays of common sycamore are
much broader in tangential section (pl. XXXV, pr) than those of
the other two species. They have an average width of 14 cells,
and the ratio of width to height is 1:5. The rays are narrowest in
the California sycamore (pl. XXXVII, pr); they average only 5
cells wide, and the ratio of width to height is 1:26. The rays
in Arizona sycamore (pl. XXXVI, pr) average 8 cells wide, and
the ratio of width to height is 1:12. In all species the pith rays
abruptly widen in transverse section at the boundary of each
annual ring of growth (pl. XXXIII, pr). The pith ray cells as
seen in radial section are usually much longer than they are high,
00
BOTANICAL GAZETTE
[DECEMBER
—
488
le °
io @
Si 2
S :
isk |
fem @
E E|
— @
Pet ey
= 3
= Bia
t => fe?
= be
—> ?e
=f ooh ( °
J=ter fal :
les ok f e
= ee :
= Ci ff
— % 0 me
=) | s
=| \ 1
[2]
SESES
c
zs
oa a
Oe ey, tan
Fic. 2.—A, wood parenchyma fiber of P.
racemosa with leva simple pits (sp) and 3 small
bordered pits (bp); also showing tubelike projec-
tions (¢); 250; B, wood parenchyma fiber of
P. racemosa with Seotcben pits (6p); also show- es
ing tubelike projections (¢) often with pit (9); \
‘150; C, intermediate fiber of P. occidentalis with oblique
oval bordered Lay (bp); X1 as D, intermediate form between
fiber, from wood of P. Wrightii, showing
slitlike perforations (slp) ctl to those in tracheids, small
vertical slitlike bordered pits (bp), and oblique simple pits og
(sp’); eu . wood P. racemosa, showing vertical (ome
slitlik enlarged to show
of
e bordered pits (bp); 100; F, end of wood fiber of P. racemosa
form of bordered pits (bp); 200; G, forked end of a wood fiber of P. racemosa, X359-
1917] BRUSH—SYCAMORE WOODS 489
except toward the outer boundary of each year’s growth, where
they become very much shorter (pl. XXXVIII, pr). The cross-
walls between the ray cells are sometimes vertical, but more often
they are slightly oblique.
Analytical key
Pith rays 0.22-0.34 mm. wide (average 0.29 mm. or 14 cells);
average height, 1.36 mm. or 50 cells; average ratio of width to
height, 5.—P. occidentalis (pls. XXXII, XXXV, XXXVIII).
Pith rays 0.10-0.22 mm. wide (average 0.16 mm. or 8 cells);
average height, 1.84 mm. or 84 cells; average ratio to height, 12.—
P. Wrightii (pls. XX XIII, XXXVI).
ce ee a ma
LZ oe QS Setrst fer + tS
ieee 2 o 2 200 0 09 s¥
Se —=S——
! 7. , © 7 o © 6 : , oo ©
Pr erssah o*o 2 o. «9%. 9 A -—* 'er_
® = t =
Fic. 3.—Radial view of portion of pith ray of P. racemosa: a, individual paren-
chyma cells; bp, bordered pits; c, crystal; 200.
Pith rays 0.04-0.20 mm. wide (average 0.09 mm. or 5 cells);
average height, 2.36 mm. or 107 cells; average ratio of width to
height, 26.—P. racemosa (pls. XXXIV, XXXVII).
Individual characteristics
P. occidentalis L., common sycamore
(pls. XXXII, XXXV, XXXVIIT)
Distribution—Southeastern New Hampshire and southern
Maine to northern Vermont and Lake Ontario (Don River, near
north shores of the lake); west to eastern Nebraska and Kansas,
and south to northern Florida, central Alabama and Mississippi,
and Texas (Brazos River and thence south to Devils River).
Uses.—Common sycamore is used to a large extent for plug
tobacco boxes, furniture, butchers’ blocks, ox yokes, wooden bowls,
and cooperage, blind wood in cabinet work, chairs, refrigerators,
490 BOTANICAL GAZETTE [DECEMBER
parquetry, sewing machines, picture molding, saddletrees, vehi-
cles, and bookcases. It is cut radially for veneer. This is because
the “‘silver grain,”’ made by the large pith rays, is very prominent,
thus giving the appearance of oak.
Gross characters—The wood is moderately hard and heavy, not
strong, close-grained, very tough, usually exceedingly cross-grained,
difficult to split, and not durable in contact with the soil. It is
easier to split when dry, but is liable to warp in seasoning. The
heartwood is a reddish brown, especially in older trees, with a
decidedly reddish color in the pith rays; the sapwood is light
brown, and the transition from sapwood to heartwood is quite
gradual. The annual rings of growth (pl. XXXII) are less clearly
defined than in the two western species. The pith rays are very
conspicuous (pl. XXXII, pr).
Vessels (transverse section, pl. XXXII, v)—These occur either
singly or else in irregular groups of 2-5. The last arrangement is
the usual one in the early wood. At the beginning of each annual
ring and immediately adjacent to the several rows of much radially
flattened wood fibers which mark the end of the preceding growth
layer is an interrupted row of tangentially compressed vessels
(pl. XXXII, v) somewhat larger than those formed later. The
vessels diminish slightly in diameter and in number toward the
outer part of the annual ring, where they are usually isolated. They
measure 0.06—o.10 mm., with an average of 0.083 mm. in diameter
(table II). Vessel segments (tangential section, pl. XXXV, 2)
vary from 0.72 to 0.89 mm. in length, with an average of 0.786
mm. (table III). The vessel walls are much thinner than those
of the surrounding cells. Where two segments join endwise, the
opening between them is large and elliptical, or often the end walls
are not completely absorbed, leaving a scalariform or ladder-like
opening, with 1~25 bars like those found in the ends of the tracheids
(fig. 1, B). These bars are much narrower than the openings OT
slits between them and are often branched. The oblique end of
the vessel segment is often prolonged, forming a projection which
overlaps the adjoining segment above and below. The vessel walls
are marked by vertical and horizontal rows of numerous small, slit-
like, bordered pits, which are horizontal, or often slightly oblique.
1917] BRUSH—SYCAMORE WOODS 491
These serve as means of communication between vessels. Large
transversely elongated, oval, simple pits connect the vessels with
wood parenchyma fibers (fig. 1, A, sp).
Tracheids (pl. XXXII, t).—These are numerous and variable in
form, and all gradations between vessels and wood fibers may’ be
found. True tracheids have numerous slightly oblique, elliptical,
or slitlike simple pits (fig. 1, Z, sp) throughout their entire length,
and at both ends there are many long slitlike openings where they
overlap other tracheids above and below (fig. 1, E, slp). In addi-
tion to these pits of the true tracheids most tracheids possess rows
of slitlike bordered pits and the transverse oval simple pits found
in vessels (fig. 1, Dand A, sp and bp); hence they somewhat closely
resemble vessels. Also many of the tracheids have at one or both
ends a simple perforation (fig. 1, D, p) either with or without bars,
like those in vessels, in place of the slitlike openings found in true
tracheids, or else the perforation at the end may be intermediate
between the slitlike and scalariform types (fig. 1, D, scp). Tra-
cheids are also found which resemble wood fibers, but these are not
numerous. They possess, in addition to the oblique simple pits of
tracheids, the small vertical or often slightly oblique slitlike bor-
dered pits which characterize wood fibers (fig. 2, D and E, dp).
These tracheids are usually more or less pointed at both ends and
sometimes possess small slitlike perforations similar to those found
in true tracheids (fig. 2, D, slp).
Wood fibers —These are round, angular, or flattened in trans-
verse section (pl. XXXII, wf). They are long, slender, and long-
acuminate at the ends, and are marked by numerous small slitlike,
obscurely bordered pits* (fig. 2, Eand F, bp). The pits are vertical
or oblique, often at an angle of 45°, the oblique position being
greatest in fibers with wide lumina. The ends are sharply pointed
and often conspicuously forked (fig. 2, G). They vary from 1.39
to 2.02 mm. in length, with an average of 1.63 mm. The broad
thin-walled wood fibers, as already described, often show a resem-
blance to tracheids.
Wood parenchyma fibers-—These have acute ends, are moder-
ately thin-walled, and are composed usually of 4~8 individual cells.
‘The border is hardly visible where the fibers have been isolated by maceration.
492 BOTANICAL GAZETTE [DECEMBER
Two types of wood parenchyma fibers may be distinguished in the
wood of the sycamores, although these may grade somewhat into
each other. The elements of one of these types are found adjacent
to vessels, which they somewhat resemble and with which they
communicate through horizontally elongated elliptical simple pits
(fig. 2, A, sp). Small dotlike or circular bordered pits are also
sometimes found in these elements which put the wood parenchyma
fibers in communication with one another. The cross-walls between
individual cells are usually slightly oblique and are pierced by
numerous slightly bordered pits. The second type is larger, usually
more tapering at the ends, and the individual cells composing it
vary considerably in size and form, so that frequently one individual
cell is found overlapping two other cells of the same fiber (fig. 2, B).
The cross-walls are usually oblique, often approaching the vertical,
so that the individual cells are often pointed at the end. This type
is characterized by small round or dotlike, slightly bordered’ pits
(fig. 2, B, bp), which put them in communication with pith ray cells
and other wood parenchyma fibers. The walls in certain places
are often locally thickened.
Wood parenchyma fibers slightly separated by two contiguous
vessels often connect by means of tubular outgrowths from their
lateral walls (fig. 2, A and B, #). By means of these tubular pro-
jections, which are usually pitted at the points where they join,
wood parenchyma fibers communicate with one another. Fre-
quently these projections end blindly.
Intermediate fibers (fig. 2, C).—These resemble wood parenchyma
fibers in the fact that their walls are irregularly thickened and that
their ends are somewhat blunted. They more closely resem-
ble the wood fibers in form, although broader and much shorter
5 By some investigators a pit is considered bordered only when the pit canal
widens out abruptly toward the outside of the cell wall, the outer portion forming
an angle with the inner portion of the pit canal which opens into the lumen; where
no such widening occurs the pit is simple. On this basis, however, all transitional
forms between simple and bordered pits can be found in wood cells; hence the classi-,
fication is merely an arbitrary one. It is thought best in the present paper to con-
sider pits as bordered where the walls of the pit canals are not parallel and where they
give the appearance of a border in longitudinal sections.
1917] BRUSH—SYCAMORE WOODS 493
than the average wood fiber. They have numerous oval oblique
bordered pits.
Pith rays (pls. XXXII, XXXV, XXXVIII, pr).—These are
very conspicuous. They are on the average 14 cells (0.29 mm.) in
width and are about 5 times as high. The pith ray cells are ellip-
tical in the tangential section and are usually much elongated
radially. The side walls are thickened and marked by many
dotlike slightly bordered pits which place them in communication
with the surrounding elements (fig. 3, bp). Crystals are very
abundant in the pith ray cells. :
P. Wrighttt S. Wats., Arizona sycamore
(pls. XXXII, XXXVI)
_ Distribution —Southwestern New Mexico and southern Arizona,
Mexico (Sonora).
Uses.—The wood of Arizona sycamore is little used. This is
on account of its small dimensions and the limited supply of suitable
saw logs. It is very similar in its chief structural characters to the
wood of California sycamore. While this wood does not occur in
the market, it possesses qualities useful for the same purposes as
the wood of the common sycamore, and it could be applied to
these uses were the tree larger and sufficiently abundant to warrant
its exploitation.
Gross characters.—The wood is somewhat lighter and softer and
also less cross-grained and easier to split than that of the com-
mon sycamore. It is weak, very close-grained, and quite tough,
but not very durable in contact with the soil. The sapwood is
light colored or almost white, and the heartwood is light brown
with a reddish tinge. The annual rings (pl. XXXIII) are
clearly defined on a smooth transverse section. The pith rays
are clearly visible, though not as prominent as those of the com-
mon sycamore.
Minute characters —Vessels in transverse section (pl. XX XIII, v)
are arranged singly or in groups, just as in the common sycamore
already described. In the beginning of the early wood the vessels
494 BOTANICAL GAZETTE [DECEMBER
form a fairly continuous row, but they gradually diminish in diame-
ter and in number as they enter the late wood. They vary from
0.04 to 0.09 mm., with an average of 0.076 mm. in diameter
(table II). The veined segments are relatively short in this species,
varying from 0.39 to 0.73 mm., with an average of 0.55 mm. in
length (table III). Where two vessel segments join end to end the
perforation is asinthe commonsycamore. Tracheids (pl. XXXIII,
t) are variable in form, some closely resembling vessels and others
very similar to wood fibers. Wood fibers (pl. X XXIII, wf) form
the bulk of sycamore wood. The length of these elements in
Arizona sycamore varies from 1.5 to 2 mm. in length, with an
average of 1.7 mm. They are thick-walled and pitted as in the
common sycamore. The wood parenchyma fibers and intermediate
fibers of Arizona sycamore are similar in all respects to those of the
other two species (fig. 2, A, B, C). Pith rays (pls. XXXII,
XXXVI, pr) are conspicuous; the average of the large rays is
0.16 mm. wide and about 12 times as high, and therefore much
narrower and somewhat higher than in the common sycamore.
The pith ray cells are round in the tangential section (pl. XXXVI,
pr), and are usually much elongated radially.
P. racemosa Nutt., California sycamore
(pls. XXXIV, XXXVIT)
Distribution.—California (from the lower Sacramento River
through interior valleys and coast ranges) to Lower California (San
Pedro Martir Mountain).
Uses.—California sycamore wood, because of its limited supply,
is used only locally and only to a small extent. It is somewhat
lighter in weight and in color than the common sycamore, and is
also less cross-grained and hence easier to work. Users of this wood
claim that it is more durable and is also less liable to warp than the
common sycamore. It should be useful for all purposes for which
common sycamore is used except where great toughness is required,
as in butchers’ blocks, ox yokes, wooden bowls, etc. It should be
found useful especially for tobacco boxes, for which the wood of the
eastern sycamore is so extensively used.
1917] BRUSH—SYCAMORE WOODS 495
Gross characters.—In general appearance the wood is similar to
that of Arizona sycamore, although it is slightly lighter, softer,
and more durable. Although moderately tough, somewhat cross-
grained, and rather difficult to split and work, it is relatively weak.
The heartwood is light brown, slightly tinged with red; the sapwood
is light yellowish brown. The annual rings of growth are more or
less clearly defined on a smooth transverse section (pl. XXXIV).
The pith rays (pl. XXXIV, pr) appear as numerous conspicuous
thin lines.
Minute characters.—Vessels (pl. XXXIV, v) are quite evenly
distributed throughout the annual rings of growth and are grouped
as in the other two species already described. The beginning of
each annual ring is marked by a well defined row of slightly tan-
gentially flattened pores larger than those formed later. They
measure 0.06-0.09 mm. in diameter and average 0.073 mm.
(table II). The average length of vessel segments is 0.677 mm.,
varying from 0.61 to 0.75 mm. in length (table III). Tracheids
(pl. XXXIV, #) do not differ from those in the other two species
described and show the same transitional forms to vessels and
wood fibers. Wood fibers (pl. XXXIV, wf) are from 1.26 to
1.93 mm. long, with an average length of 1.55 mm. (table IV).
Wood parenchyma fibers and intermediate fibers are in all respects
similar to those of the other two species (fig. 2, A,B,C). Pith
rays (pls. XXXIV, XXXVII, pr) are conspicuous in all sections.
hey are narrowest in this species and have an average width of
5 cells (0.09 mm.). They are on an average 26 times as high as
wide, being thus much higher than in the other two species. The
pith ray cells in the tangential section are round and slightly
higher than broad.
Forrest SERVICE
Wasuincton, D.C.
EXPLANATION OF PLATES XXXTI-XXXVHI
PLate XXXII.—Transverse section of wood of common sycamore (P.
occidentalis), showing parts of two annual rings of growth; ew, early wood;
lw, late wood; 2, vessels; wf, wood fibers; pr, pith rays.
496 BOTANICAL GAZETTE [DECEMBER
PLATE XXXIII.—Transverse section of wood of Arizona sycamore
(P. Wrightii), showing parts of two annual rings of Dake ew, early wood;
lw, late wood; v, vessels; wf, wood fibers; pr, pith ra
PLATE XXXIV. —Transverse section of wood - ‘Colifotnia sycamore
(P. racemosa), showing parts of two annual rings of growth: ew, early wood;
lw, late wood; v, vessels; wf, wood fibers; pr, pith rays.
PratE XXXV.—Tangential section of wood of common sycamore
(P. occidentalis), showing pith rays (pr) in cross-section and vessels (v) and
wood fibers (wf) in longitudinal section.
Pirate XXXVI.—Tangential section of wood of Arizona sycamore (P.
Wrightii): v, vessels; wf, wood fibers; pr, pith rays.
PLaTE XXXVII.—Tangential section of wood of California sycamore
(P. racemosa): v, vessels; wf, wood fibers; pr, pith rays.
PLaTtE XXXVIII.—Radial section a wood of common sycamote (P.
occidentalis): v, vessels; wf, wood fibers; pr, pith rays.
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AGENCY OF FIRE IN PROPAGATION OF
LONGLEAF PINES
E. F. ANDREWS
(WITH FIVE FIGURES)
The important part played by forest fires in the life history of
the longleaf pine has been recognized by a number of recent writers,
and HARPER’ even goes so far as to say “that if it were possible
to prevent forest fires absolutely the longleaf pine . . . . would
soon become extinct.” The connection between the periodic
recurrence of these catastrophes and the success of the pine seed-
lings in competing for possession of the soil was pointed out by
Mrs. ELLEN Catt Lona, of Tallahassee, more than 25 years ago,
but the suggestion appears on the face of it so at variance with
universal experience as to give little occasion for surprise that it
should have been received with incredulity, or at best with indiffer-
ence, by those unacquainted with the adaptive provisions of the
species and the conditions prevailing in its habitat.
The writer has recently been favored with exceptional oppor-
tunities for investigating this subject by means of an experiment
carried out by nature herself, in the native home of the longleafs,
with all the exactness of detail that could be expected in a well
ordered laboratory. Even that refined test of scientific accuracy,
a control experiment, was provided by a neighboring group of the
same species that was not exposed to fire on the occasion referred to.
The scene of this spontaneous demonstration lies on the northern
slope of Lavender Mountain, in Floyd County, Georgia, a ridge
of the Southern Appalachians which is certainly very near, if not
actually itself, the extreme inland and upland limit of the longleaf
pines as they occur at present. The crest of the ridge, accord-
ing to the United States Geological Survey, attains a maximum
height of 1695 ft. above sea level, and extends for 12 miles or
more in an approximately east and west direction. It is divided
* Economic Botany of Alabama, Part 1, p. 26.
497] [Botanical Gaze tte,vol. 64
498 BOTANICAL GAZETTE [DECEMBER
transversely by three deep depressions, or gaps, through which traffic
is carried on, and the intervals between the gaps are subdivided
by numerous ravines into more or less widely separated spurs and
knobs. The southern slopes are covered with the remains of great
forests of this valuable timber, interspersed with various hard-
wood trees and with shortleaf pines (P. virginiana and P. echinata).
Fic. 1.—Young longleaf pines reforesting mountain side after removal of ripe timber
They have repeatedly been cut for lumber and burned over by
“round fires” started in spring by farmers to provide a free
range for their cattle, but the longleafs continue to reproduce them-
selves with a pertinacity which, if not too diligently thwarted by
the blundering incompetence of county officials and the short-
sighted greed of ignorant timber cutters, will in the course of 4
generation or two repopulate the southern mountain slopes with a
new forest growth sprung from the old stock (fig. 1).
1917] ANDREWS—LONGLEAF PINES 499
While there are traditions of the former presence of this species
on the northern side of the mountain, the only traces of them that
_ I have been able to find there consist of two small, isolated groups
which furnished the apparatus for nature’s instructive experiment
alluded to. They are situated on opposite sides of a deep ravine
which starts near the top of the mountain, at Fouché Gap (the
westernmost of the three passes), and descends in a gradually
widening rift to the bottom. The larger and more important of
these groups occupies a portion of a steep incline between the crest
of the ridge and a now abandoned road that winds along the eastern
edge of the ravine. It numbered only five individuals, so far as
could be seen when I first took note of them, in the summer of 1913.
Of these, the rugged patriarch shown in the center of fig. 2, together
with two smaller specimens in the background, one of them a mere
sapling, were the only members of the colony conspicuous enough
to attract the attention of any but a particularly interested observer.
The other two were seedlings not over 4-5 dm. in height, and at
this stage of development, when the needles are the only part
above ground, so like the coarse grasses around them that even an
expert, unless keenly on the lookout, would be liable to pass them
by unnoticed (fig. 3).
This group of five individuals was scattered over an area of
half an acre, more or less, on the edge of an open copsewood which
has repeatedly been cut for timber and cleared of undergrowth by
minor forest fires. The rest of the declivity, from the gap to the
crest of the ridge, had been cleared several years before for cotton
planting, but after a short trial was abandoned as too rugged for
cultivation. It was at this time (July 1913) neck deep in weeds,
mixed with a scrub growth of brush and brambles; and not being
in quest of the zoological specimens likely to abound in such places,
I did not explore this jungle until two years later, after one of the
periodical spring fires had cleared the ground.
The second group, which served as the ‘control,’ is situated
on the farther side of a low spur or knoll, separated from the
neighboring colony by the intervening ravine and the wooded
crown of the knoll. It included, when first observed, four indi-
viduals, three of which were adults of full cone-bearing age, the
590 BOTANICAL GAZETTE [DECEMBER
largest one measuring 2 m. in girth. The offspring of these was
limited to one solitary seedling, a disproportion the significance of
which will be apparent later, when compared with the progeny of
the ‘“‘patriarch”’ on the other side of the gorge. The soil in both
situations is the same, a hard, dry, rocky clay, with a characteristic
Fic. 2.—In foreground, small portion of old clearing as it appeared after fire,
with ‘‘patriarch” on border between it and copsewood; tall Pinus echinata diml
outlined at extreme left stands near brow of opposite slope of ravine; beyond is knoll
on farther side of which “control” group is situated.
ground cover of Pteris aquilina, Tephrosia virginica, and a number
of coarse grasses that have a strikingly familiar aspect to one
acquainted with the vegetation of the great pine region of the South
Atlantic coastal plain. The typical wire grass (Aristida stricta) of
1917 Al tWS—LO] We: NE 501
] NDREWS—LONGLEAF PINES
the southern forests is here replaced bya correspondingly arid growth
of “old field broom” (principally Andropogon furcatus, A. virginicus,
and A. scoparius), with a few sedges (Scleria triglomerata, Cyperus
retrofractus, etc.) intermixed. In fact, the only difference in the
environment of the two groups is the isolated position of the knoll,
Fic. 3.—Large clump of spearlike leaves near upper lefthand corner is longleaf
seedling; others are grasses that have sprung up since fire; skeleton plant on right
and white patches in background are hardwood seedlings and bushes killed by fire
that left pine seedling unharmed.
the top of which is protected by an encircling turnpike road and by
the wooded slopes of two deep ravines, watered by mountain springs
and clothed with a heavy growth of broad-leaved trees, conditions
which oppose an effective barrier against the spread of fire.
502 BOTANICAL GAZETTE [DECEMBER
It was not until April 1915 that I made another visit to these
straggling longleaf outposts, which had interested me at first
merely as landmarks of what seemed to be the ultima Thule of
their advance in this direction. But a great surprise awaited me.
The region around the gap had recently been burned over, and amid
the wreckage of skeleton limbs and blackened stubs to which the
weedy jungle in the old clearing was now reduced, there appeared
a thriving colony of 33 young longleafs, ranging from a few deci-
meters to a meter or more in height. This new growth was con-
fined mainly to the old clearing, although the “‘patriarch,”’ whose
progeny it presumably is, stands squarely on the border line between
the old cotton field and the copsewood, and had no doubt dis-
tributed his favors impartially to both. But the absence of trees
in the clearing would naturally facilitate the scattering of seeds in
that direction, and during the first year or two, before the weeds and
brush began to crowd them out, they would germinate freely in the
open ground. I had simply overlooked them on my former visit,
for the reason that they were hidden in the jungle, where, after
making a successful start in life during the palmy days before their
little Belgium was overrun by the horde of weedy invaders, they
were at last overpowered by numbers and buried out of sight.
Deprived of the sunshine so necessary to this sun-loving race,
all save the oldest and strongest among them must have perished but
for the timely intervention of their powerful ally, the fire, which
swept away all rivals and left the young longleafs in undisputed
possession of the soil. That such was the case, we have their own
direct testimony, for every one of them bore unmistakable marks
of fire. Some were so scorched and blackened that any one un-
acquainted with the habit of the species would unhesitatingly
have pronounced them dead. An examination, however, of a
number of the worst injured plants showed that in not a single
instance had the growing point been killed, or even seriously
damaged.
On the other side of the ravine conditions were unchanged
except that a new road had been cut around the knoll since my
former visit, almost completely encircling it, and one of the adult
pines that stood in their way had been felled by the road builders.
1917] ANDREWS—LONGLEAF PINES 503
The fire had not spread in this direction, and I had some difficulty
in finding again, among the coarse grasses which these nurslings
so closely resemble, the solitary seedling upon which the future
hopes of the colony depend. A careful search among the under-
growth failed to bring to light any further additions to this decadent
family, and, as matters now stand, it looks as though the last
remnants of the longleaf forest that once clothed the knoll were
doomed to early extinction.’
It would, of course, be rash to attribute this result solely to the
absence of fires. Various other factors may intervene, among
which must be reckoned the infrequency of seeding that char-
acterizes this species, a full crop being produced only at intervals
of four or five years. If a forest fire should occur during one of
these “lean’’ periods, it would have comparatively little effect,
since there would be few seedlings to take advantage of the oppor-
tunity offered, while one closely preceding a season of abundance
would prepare the way for a proportionate increase in the longleaf
population.
Another fact to be considered is that the early growth of the
longleaf seedling is very slow. The main energy of the plant
during the first year or two is expended in developing the long
taproot which enables it to cope successfully with the poverty of its
habitat by making the most of the meager resources of the soil, and
later provides a safe anchorage for the towering shaft of the adult
tree. The young specimen shown in fig. 4, and scarcely distinguish-
able as yet from a clump of grass, is not less than two years old, and
may be more. But while giving due weight to these considerations,
I think that after we have studied the effects of fire a little more
closely in those cases where its agency is too obvious to be doubted,
we cannot deny that it is, and has been in the past, an important
factor in the propagation and distribution of the longleaf pines.
In July and August of the same year (1915) I made a longer
stay on the mountain, during which time I was able to continue
my observations on the pines to better advantage. In the lower
?Later observations (September 1917) show a flourishing group of 66 saplings
and seedlings in the first colony; while the lower one on the knoll has been reduced
to 2 individuals by the loss of the seedling and one of the adult trees.
504 BOTANICAL GAZETTE [DECEMBER
group, on the knoll, there was little of interest to record, every-
thing remaining very much as when I last saw it. On the upper
slope, however, matters were very different, and a more exact
count brought the census of the new generation up to 40. Of this
number, all of those within the old clearing must have germinated
during the 7 or 8 years since the cultivation of this part of the land
Fic. 4.—Thrifty longleaf seedling that has established itself successfully on
stratum of almost solid rock, made possible by long taproot reaching far down into
subsoil.
was abandoned, for they would assuredly have been weeded out had
any of them dared to show their heads above ground where “cotton
was king.” To estimate the ages of different individuals with
accuracy, however, is not easy, on account of the great irregularity
in the rate of growth. While very slow during the first 2 or 3
years, as already pointed out, it becomes proportionately rapid
after the critical period of “infant mortality” is past. The growth
for the year 1915, up to the first of August, on two saplings of
2.75 and 2 m. in height respectively, was found by measurement
1917] ANDREWS—LONGLEAF PINES 505
to be approximately 8 and 7.5 dm., while seedlings 12-18 cm.
high showed a gain of only 2-4 cm. for the same period.
These figures show that the young longleaf, after attaining
adolescence, is fully capable of holding its own in the competitive
strife of the plant world. The chief danger to the species in this un-
ceasing contest is in the risk that the seedling, during its long period
of infancy, may be starved and crowded to death by the rapidly
advancing host of weeds and bushes that outstrip it in the battle
for food and sunlight. Their only safeguard against these enemies
is, as we have seen, the forest fire.
_ This naturally brings up the question, how does it happen that
the young pines themselves are not killed by the heat which
destroys their hardier competitors? The answer is before our
eyes. The great rosettes of bristling needles, which give to the
longleaf pine its venerable aspect, are not the mere decorative
emblems of ancient descent that they seem. They are fulfilling
the important function of a defensive armor against the most
destructive enemy (after man) that the plant population of the
world is exposed to. The young of most species quickly succumb
at the first onset of even an ordinary ground fire; but the longleaf
pine seedling has its growing point closely enveloped in a crown of
spearlike needles, as shown in fig. 4, before the stem begins to rise
above the ground. These may be anywhere from 20 to 40 cm.
long, including the sheaths, which average about 3-4 cm. When
fresh they ignite so slowly as to be practically incombustible.
Strictly speaking, they can hardly be said to ignite at all, but are
bitten off and consumed where the fire comes in contact with them.
Moreover, the application of heat causes a violent sizzling and
contortion of the parts affected, accompanied by a series of small
explosions which are sometimes capable of extinguishing a match;
and I have even known them, on one occasion, to put out the
flame of a candle. At another time, I was trying to ignite a fresh
“pinetop”’ (as these tufts are called in our Georgia vernacular) by
the flame of a kerosene lamp, when it fumed and sputtered and
caused such a commotion in the burning wick that I cut short the
experiment for fear of exploding the lamp and transferred my
operations to the kitchen. There was a slow wood fire in the
506 BOTANICAL GAZETTE. [DECEMBER
stove, into which I thrust the pinetop, and awaited results, watch
in hand. When I removed the stub at the end of 4 minutes, the
needles had all been consumed, but the sheaths, especially those
of the vigorous young fascicles crowded around the growing point,
remained for the most part intact. The bud itself, though consid-
erably scorched and blackened externally, appeared, like the stem,
not to have suffered beyond the possibility of recovery, though
this point, as the final result will show, was open to doubt. |
It may be explained here that in excursions through the moun-
tains it is desirable to avoid all unnecessary encumbrances in the
way of luggage, and, as the conditions of life are very primitive in
the regions of greatest interest to the botanist, one often has to
resort to homely makeshifts when supplementing observation by ex-
periment. It is surprising, however, what interesting results may
sometimes be obtained by very simple means when one is deter-
mined to get to the bottom of a thing.
To complete the experiment, I next placed a couple of fresh
pinetops in an upright position over a brisk blaze of chips and twigs
out of doors, so as to approximate, as closely as possible, the normal
conditions of an ordinary brush fire. After 8.5 minutes, when
the flame had subsided and the needles were all burned away,
down to their sheathed bases, I placed the stubs in water, together
with the one that had been subjected to the ordeal of the kitchen
stove on the day before. At the end of 12 days, when my stay on
the mountain came to an end, the latter was found to have sustained
internal injuries which left it in all probability beyond recovery.
The other two came out of the fiery ordeal, if not altogether un-
scathed, yet with an appearance of vitality sufficiently unimpaired
to warrant the presumption that had they remained attached to the
living stem, like their kindred in nature’s outdoor experiment, they
would, like them, quickly recover from the effects of the fire.
The effectiveness of this provision for the safety of posterity is
further assured by the tendency of the needles to persist on the
stem of the young shoot for several years, until the more delicate
parts are lifted beyond the reach of danger. As the growth of
the sapling progresses, and the increasing thickness of the bark
provides for the protection of the stem, the needles become massed
1917] ANDREWS—LONGLEAF PINES 507
around the growing axes at the end of the branches, where they
form the tassel-like clusters or ‘‘pinetops”’ which are such a striking
characteristic of the longleaf pines (fig. 5). Under the influence of
light the lateral stems supporting these tassels tend to curve upward.
This upright position has the advantage that the fire, which
Fic. 5.—Young longleaf pine with stem surrounded by bristlin
g chevaux-de-frise
of needles, growth of several successive years.
ordinarily makes its attack from below, has to cut its way through
the entire phalanx of protecting needles before it can reach the
growing point. If the rosettes were drooping as in the winter
condition of the white pine, they would, instead of protecting the
buds, act as refractors to converge the heat upon them.
508 BOTANICAL GAZETTE [DECEMBER
With such efficient fire protection it can easily be seen why the
longleaf seedling is able to withstand a degree of heat that would be
fatal to older and in other respects hardier plants. The same facts
also explain why, in a state of nature, these trees tend either to
congregate in pure forests over large areas or to become extinct if
exposed to unrestricted competition with hardwoods. In the
latter case the older conifers may hold their own for a time, but
as these die out from superannuation or other causes, the new
generation that should replace them, unable to develop in the shade,
and cut off from the sunlight by the broad leaves of the hardwoods,
fails to reach maturity and the race in time becomes extinct. On the
other hand, when forest fires, especially of the minor type known
as ‘“‘ground fires” and “brush fires,’’ occur at not too frequent
intervals, the immunity of the pines enables them to take the lead
in the work of reforestation, and through the gradual elimination
of their rivals to become finally the sole possessors of the soil.
Rome, Ga.
PERMEABILITY OF THE CELL WALLS OF ALLIUM
5: C. BReoors
Many investigators have reported that the tissues of higher
plants are almost if not quite impermeable to inorganic salts.
They have usually attributed this phenomenon to the imperme-
ability of the protoplasm to the salts used. It is quite probable,
however, that the cell walls themselves may exert an important
influence on the permeability of tissues.. It is of interest, therefore,
to point out a striking example of the impermeability of the cell
wall, which was found when it was attempted to investigate, by the
diffusion method recently described by the writer,’ the perme-
ability of epidermis from the inner surface of bulb scales of the onion.
The principle of the experiment and the apparatus used were the
same as in the writer’s experiments on Laminaria, as recorded in
the paper cited. .Certain modifications were necessary, however.
In order to avoid injury due to drying out of the epidermis
(which consists of a single layer of cells), it was necessary to reduce
as much as possible the time intervening between the act of stripping
the epidermis from the scale and that of filling the cells with solu-
tions. The whole operation usually occupied about 30 seconds, a
time which caused no observable injury to the cells.
Dead material was prepared by exposing freshly sa ee
sheets of tissue to chloroform vapor for a period of one hour, then
immediately immersing them in a large volume of distilled water,
which was several times renewed. After 15 days in distilled water
the dead tissue was used in the usual manner.
The salt solutions used in the lower cells were always 0.05 M,
a concentration hypotonic to the living cells of the onion epidermis.
In the upper cells there was placed distilled water having a specific
conductivity of about 2xX10~° mhos. Extreme precautions were
‘used to prevent access of dust, acid vapors, or any other soluble
material to the distilled water in the upper cells. In all the
* Brooks, S. C., A new method of studying permeability. Bor. Gaz. 64: 306-317.
Sigs. 2. 1917.
599] [Botanical Gazette, vol. 64
510 BOTANICAL GAZETTE [DECEMBER
experiments on this tissue the distilled water was obtained by dis-
tillation from an apparatus made entirely of glass, and which had
been in constant operation for several weeks prior to the collection
of the sample here used.?_ All the kations were used in the form of
chlorides, thus making it possible to determine their concentration
in the upper cell by two entirely independent methods. The con-
ductance of known concentrations from 10~7 M to 1073 M of the
salts used was determined and a curve plotted showing for each
salt the concentrations corresponding to any given conductance.
The concentration of a given salt diffusing into the distilled water
in the upper cell was then ascertained by comparison of the con-
ductance of the solution in the upper cell with the curve for the
corresponding salt. In addition, the chlorides in the upper cell
were determined nephelometrically by the method of RICHARDS
and WELLs.3
In neither living nor dead tissues could the presence of chlorides
in the upper cell in excess of 3X10~5M be detected nephelo-
metrically, even during experiments whose duration exceeded 24
hours. The changes in conductivity were also such as would indi-
cate a negligible increase in the concentration. It seems therefore
that little or no salt can pass through the epidermis.
Experiments were then tried to determine the permeability
of the tissue to dyes. The diffusion of Bordeaux red through the
diaphragm from an o.1 per cent aqueous solution in the lower cell
into distilled water in the upper during 96 hours was insufficient
to cause any visible change in the color of the distilled water. A
similar experiment, in which the lower cell contained a 1 per cent
aqueous solution of eosin (Merck’s eosin bluish), was continued
for 7 days; at the end of that time the distilled water in the uppet
cell could not be distinguished in color from fresh distilled water,
even by the use of a colorimeter.
The experiments on dyes (as well as those on acids and alkalies,
subsequently described) were performed on dead tissue.
? Water distilled from glass becomes better the longer distillation is continued, -
since the constant exposure to steam and hot water soon removes the more soluble
constituents of the glass. Water such as that here used may be regarded as having no
appreciable toxicity.
3 Ricuarps, T. W., and Wexts, R. C., The nephelometer, an instrument for
detecting and measuring opalescent precipitates. Amer. Chem. Jour. 31:235- 194
1917] BROOKS—PERMEABILITY 511
In the use of indicators we possess an extremely sensitive and
reliable means of demonstrating the presence of small amounts
of free acid or alkali in a solution. It would be possible therefore
to detect the diffusion through the diaphragm of tissue of small
amounts of hydrochloric acid or sodium hydroxide by adding a
small amount of a suitable indicator to the distilled water in the
upper cell of the apparatus. In the lower cells 0.1 M solutions of
the acid and alkali were used.
A period of 43 hours was insufficient to allow the passage of an
amount of sodium hydroxide great enough to cause any change in
the color of the distilled water containing about 0.01 per cent of
phenolphthalein, as determined by comparison in a colorimeter
with fresh distilled water. The change of hydroxyl-ion concentra-
tion necessary to cause the first visible change in the color of the
phenolphthalein would be that from 1 X107~° M to 1X1075 M.
The turning point of Congo red lies at a hydrogen-ion concen-
tration of 1X10~* M. An increase of less than 1X10~*M in the ©
hydrogen-ion concentration of distilled water containing Congo
red will then cause the appearance of the blue coloration in the
indicator. Experiments were conducted in which the lower cells
were filled with o.1 M hydrochloric acid, and the upper cells with
distilled water containing barely sufficient Congo red to cause a
distinct red coloration; these showed that a period of 3-5 hours
was sufficient to cause the color change in the indicator. Control
experiments in which the lower cell was filled with pure distilled
water showed no color change in the upper cells during 19 hours.
In order to eliminate the possibility that the permeability to
hydrogen ions was the result of the action of the 0.1 M hydro-
chloric acid on the tissue, several of the cells in which there had
been a diffusion of acid were simply rinsed out thoroughly, and the
lower cell finally filled (after preliminary rinsing with the solution)
with o.1 M sodium hydroxide. The upper cell was filled with
distilled water containing a slight amount of phenolphthalein.
There was no color change in the distilled water up to the end of
the experiment, a period of 3 days.
The inner epidermis of onion bulb scales, at least when its cells
are dead, is therefore but slightly permeable to hydrochloric acid,
and not perceptibly so to any other of the substances tried. These
512 BOTANICAL GAZETTE [DECEMBER
included sodium, calcium, and aluminium chlorides, Bordeaux red,
eosin, and sodium hydroxide.
This extraordinary impermeability is confined to the exterior
cell walls of the epidermis, as will be seen by the following simple |
experiment. A sheet of epidermis stripped from the scale and
mounted in water on an ordinary microscope slide, then irrigated
with a o.4 M sodium chloride solution, was strongly plasmolyzed
within 30 seconds. In order that plasmolysis should occur, it was
necessary that the plasmolyzing solute should pass into the space
between the cell wall and the retracted protoplast. Some part
of the cell wall is therefore freely permeable to sodium chloride.
Pieces of the scale, about 2 cm. square, with the epidermis still
in place, were then placed in a 0.4 M sodium chloride solution.
At intervals up to 30 minutes pieces were withdrawn, the surface
dried with filter paper, and a small piece of epidermis from near
the center of the piece of scale removed. These were placed
between a microscope slide and cover slip, no water being added,
and in all cases their cells were found to be wholly normal in appear-
ance; but a few seconds’ irrigation with an o.4 M. sodium chloride
solution now sufficed to cause violent plasmolysis. These experi-
ments show that the exterior walls of the epidermal cells form a
continuous layer highly impermeable to most substances and com-
parable to certain seed coats as described by previous investigators.’
Summary
1. The exterior cell wall of the epidermis from the inner surface
of onion bulb scales is slightly permeable to hydrochloric acid,
while it is practically impermeable to various salts, dyes, and to
sodium hydroxide.
2. It is necessary to consider the influence of impermeable cell
walls in interpreting experiments on the permeability of plant
tissues.
LABORATORY OF PLANT PHYSIOLOGY
HARVARD UNIVERSITY
‘Cf. Brown, A., The selective permeability of the coverings of the seeds of
Hordeum vulgare. Proc. Roy. Soc. London, B 81:82. 1909; SCHROEDER, H.,
die selektive permeable Hiille des Weizenkornes. Flora 102:186. rgtt; SHULL, C. A.,
Semipermeability of seed coats. Bot. GAz. 56:169-199. 1913.
BRIEFER ARTICLES
PYRENOTHRIX NIGRA, GEN. ET SP. NOV.
’ (WITH FOUR FIGURES)
The material upon which the new genus and species of lichens here
described is based was collected by Professor RoLAND THAXTER, of
Harvard University, in Florida in 1897. I wish to acknowledge my
indebtedness to Professor THAxTER for his kindness in placing the
material at my disposal for study and description. On account of the
distinctive combination of a byssine thallus and a teases ode fruit
this new genus may appropriately be named as follows
Pyrenothrix, gen. nov.—Thallus crustaceo-byssinus ecorticatus sub-
strato arcte adnatus gelatinosus, ex hyphis tenuibus leptodermaticis
crebre septatis ramosis, filamenta gonidiorum dense obducentibus.
Gonidia ad species Scytonemae pertinentia filamentis implexis. Peri-
thecia tenues coriacea pseudoparenchymatica, integra simplices recta
nuda nigrescentia, in gonidiis sessilia nunquam immersa, ostiolis parum
distinctis. Paraphyses persistentes simplices filiformes. Asci clavati.
Sporae ee murali-divisae cellulis subcubicis. Sper-
magonia non visa.
This new genus, by reason of having gonidia of the Scytonema type and
fruit of the perithecial form (figs. 1, 2), would appear to belong most naturally
to the family Pyrenidiaceae, as coumtituted by ZAHLBRUCKNER (ENGLER and
PRANTL, Die Natiirlichen Pflanzenfamilien, Teil I, Abt. 1, p. 76), but differs
from all of the genera of that family hitherto described in the byssine character
of the thallus (fig. 1), and in the muriform spores (fig. 4). When examined
under the microscope, the structure of the thallus and the relation of hyphae
— ~ebacgag oy sonia ig nee vegisiee that of Coenogonium (fig. 2). Without
question, ““What isa lichen ?”’ it may be said that
if Racca | is a lichen ety P imei is a lichen, as the two are strictly
analogous. That the perithecia are not those of a secondary parasite or merely
accidentally associated with the filaments of the alga is proved by the observa-
tion of early stages in their development showing their origin from the web of
hyphae that envelop the gonidia (fig. 3).
Pyrenothrix nigra, sp. nov.—Thallus fusco-nigricans byssinus sub-
strato arcte adnatus late effusus non limitatus, sicco nec flaccido nec
513] [Botanical Gazette, vol. 64
514 BOTANICAL GAZETTE [DECEMBER
spongioso, madefacto molle gelatinoso, ex hyphis tenuibus (3-4 » crassis)
septatis torulosis crebre ramosis, filamenta gonidiorum crebre obducen-
tibus; gonidiis Scytonematicis filamentis, crassitudine 13-18 », vaginis
tenuis homogeneis non lamellosis, flexuosis implexis, rarius pseudora-
mosis. Perithecia minuta, altit. 200-225 w, crassit. 160-175 #, pyri-
formes collo crasso breveque, primum fuliginea demum nigrescentia,
ostiolo minute parum distincto. Paraphyses persistentes simplices fili-
formes sat flexuosae. Asci clavatae, 8-spori. Sporae fumoso-nigricantes,
3 4
Fics. et i whe ‘: hue akerch, X4y; Fig. 2, end of gonidial filament, showing
an (
falce hranc
part omitted for clearness), X385; fig- 3,
early stage in formation of perithecium, 385; fig. 4, spores, X 385.
oblongae vel late seh ae oe ba cpanees 5-6 loculares,
2 locellati, 17-20 6-9
Thallus sicealak HEE. spreading over the substratum without
definite limits and closely adnate, byssine, when wet soft and gelatinous,
when dry harsh and not at all spongy; made up of gonidia of the Scy-
tonema type, with flexuose, intertangled filaments, 13-18 » thick, with a
thin, homogeneous sheath and infrequent false branches; the filaments
densely covered with septate, torulose, branched hyphae, 3-4 » in thick-
ness. Perithecia minute, 200-225 » high and 160-175 thick, pyri-
form with a short, thick neck, and minute, indistinct ostiole; the wall
1917] BRIEFER ARTICLES 515
thin, coriaceous, pseudoparenchymatous, at first fuliginous-brown, then
blackening. Paraphyses persistent, simple, filiform. Asci clavate,
8-spored. Spores smoky-black, oblong or broadly fusiform, muriform,
5-6 locular, with some of the cells once divided, 17—20X 6-9 p.
Abundant on the bark of scrub oaks at West Palm Beach, Florida, Decem-
ber 1897 (type!); and on living Oleander at Cocoanut Grove, Florida, No-
vember 1897; collected by Professor ROLAND THAXTER. Type specimen in
the Cryptogamic Herbarium of Harvard University.—LincoLn W. RIDDLE,
Wellesley College, Wellesley, Mass.
CURRENT LITERATURE
MINOR NOTICES
North American flora.—The third part of Vol. 10 continues the presentation
of the Agaricaceae by MurRILL,! the 12 genera of Pholiotanae being presented, ,
excepting the ae Inocybe. The 11 genera presented include 324 species,
of which 76 are described as new. The largest genera are Gymnopilus (85 spp.),
Naucoria (65 spp.), Hebeloma (50 spp.), Crepidotus (46 spp.), and Galerula
(33 spp.). The remaining 45 species are distributed among 6 genera. New
species are described in Crepidotus (7), Tubaria (4), Galerula (8), Naucoria (21),
Pluteolus (4), Mycena (2), Gymnopilus (13), and Hebeloma (17).—J. M
NOTES FOR STUDENTS
Carbon assimilation JORGENSEN and SriLes? have summarized our
knowledge of the processes involved in the assimilation of carbon by green
plants and the pigments concetned in them. The portion dealing w:th the
pigments themselves has been reviewed by Linx.3 In the introduction the
reviewers express the hope that “the following pages will be of interest to those
concerned in the development of scientific agriculture as well as to those inter-
ested in plant physiology for its own sake.” The discussion of the path of
gaseous exchange between the leaf and the surrounding atmosphere is based
mainly on the work of BLACKMAN and Brown and EscomsBe. The conclusion
reached is that the proof is now definite that the stomata are the main pat
of the intake of carbon dioxide into the assimilating aerial leaf of the higher
plants. Any intake that may occur through the cuticle is of very minor impor-
tance. Carbon assimilation is regarded as a complex of processes which prob-
ably obey quite different laws. Attention is called to the 5 obvious factors
upon which the rate of carbon assimilation in the leaf may depend: (1) carbon
dioxide supply, (2) intensity of illumination, (3) temperature, (4) water supply,
(5) quantity of chlorophyll. To these is added BLaAcKMAN’s time factor. It is
found that below 25°C. the rate of carbon assimilation a little more than
doubles for each rise of 10° C. For cherry laurel this gives a van’t Hoff curve
RILL, W. A., North American flora ro:part 3. pp. 145-226. Agaricales:
Agaricaceae (pars), Agariceae (pars). New York Botanical Garden. 1917.
2 JoRGENSEN, I., and Srites, W., Carbon assimilation. A review of recent
work on the pigments of the green leaf and the processes connected with them. New
Phytol. reprint no. 10. London. Wesley & Son. 1917.
' 3 Bor. Gaz. 62:417-421. 1916.
516
1917] CURRENT LITERATURE 517
in which the temperature coefficient for a rise of 10° C. is 2.1. In Helianthus
tuberosus it was 2.5. Below 25° C. the initial rate is maintained, but above that
temperature it falls off regularly. The higher the temperature the more rapid
is the falling off. The falling off at any given temperature is most she at
first and subsequently becomes less rapid.
Since it is thus impossible to measure the highest possible assimilation at
high temperatures, BLACKMAN estimates it by plotting his experimental results
below 25° C. (a van’t Hoff curve in which Qyo= 2.1) and continuing the curve
by assuming that the same rule is followed above that temperature. That
this curve represents the initial rate above 25° C. is confirmed in BLACKMAN’S
opinion by plotting on this same diagram (the abscissae now having a time
significance instead of a temperature significance) the values obtained for the
assimilation rate at higher temperatures, and continuing these curves back toa
point representing zero time. It is thus found that the position representing
zero time for each curve is also that representing the temperature at which the
readings were taken.
n this basis BLACKMAN concludes that there seems to be reason for the
preliminary acceptance of the theory that the initial values of assimilation
above 25° C. follow the van’t Hoff curve as they do below that temperature.
JORGENSEN and STILEs seem disposed to defend BLACKMAN against all criticisms
on this point. It must be remembered, however, that CoHEN-STUART has
shown that, according to the van’t Hoff law itself, values of Q,. are not constants
and that the velocity is not an exponential function of the temperature.
Kutypers found that such a method as BLACKMAN used on carbon assimilation
did not apply to respiration. Lrrrscu® has also found that it does not apply
to temperature and rate of growth.
In regard to the light factor, the conclusion is reached that “‘ where temper-
ature and carbon dioxide supply are in excess the rate of assimilation is in
direct proportion to the intensity of illumination.” In the case of cherry laurel
during the middle of an August day (temperature 29°5 C.) the maximum
assimilation was possible with 36 per cent of full sunlight, while in the case of
Helianthus 69 per cent was necessary
Assimilation is shown to increase directly with carbon dioxide supply
until some other factor becomes the limiting one. When this point is reached,
assimilation remains constant with further increases in carbon dioxide up to
©.0536 per cent. Above this point the rate of assimilation falls off rapidly.
BLACKMAN’s interpretation is that this is due to the sasieds effect of the
strong CO, on the protoplasm. The reviewers state that ACKMAN Care-
fully avoids premature conclusions and tries to find Se euia expressions
which will embody all his experimental results.’
4 Konn. Akad. Wetans. Amsterdam. Proc. Sec. Sci. 14:1159-1172. 1912.
5 Rev. Bor. GAZ. 50:233~234. I9g10.
6 Ann. Botany 30: 25-46.
518 BOTANICAL GAZETTE [DECEMBER
In discussing WILLSTATTER’S work on the relation between chlorophyll
content and assimilation rate, the reviewers state that “‘ WILLSTATTER advances
a simple definite $e dienes and tama 0 obtain spcteaesrnat sae ——
will support his theory arbo ti
sists of two definite paeceen, one photochemical, taking place in the dito:
roplast, and one enzymatic, taking place at the boundary between the
chloroplast and the plasma. nee cnyeen is supposedly ee during the
latter process. te. The view
is not a surprising one, however, since the relation of carbon assimilation
and of enzymatic action to temperature both seem to be special cases of
TamMaAn’s principle. The surprising thing would be that there should be only
two processes concerned. The reviewers state that under certain circum-
stances, when no other factor is limiting, the amount of chlorophyll determines
the intake of CO. by the leaf. WutisTATTER found th the amount of pigment
is not altered during the process of carbon assimilatio
he discussion of the present status of our ister of the known products
of assimilation (oxygen and carbohydrates) is based on the work done within
the last 31 years, since the earlier workers did not separate the gaseous ex-
changes due to assimilation from those due to respiration. It seems probable
that the real assimilation coefficient (taking respiration into account) approxi-
mates unity. In considering the nature of a reaction or a series of reactions, it
is very important to know the quantitative relation between initial substances
and the final products of the reaction. In carbon assimilation by green leaves
the relation between CO, taken in and O, evolved has not been definitely
established
The reviewers summarize in a table (p. 106) the evidence in regard to the
presence of various carbohydrates in the leaf. (1) Polysaccharides (exclusive
of cellulose and pectic substances); the presence of starch has of course long
been well known, and the presence of pentosans and dextrin seems to be
established. (2) Disaccharides; sucrose is certain, and maltose is doubtful.
(3) Hexoses; the presence of d-glucose and d-fructose is well recognized.
(4) Pentoses; none are positively known to be present, although there is some
evidence pointing to the presence of l-arabinose and J-xylose. Definite evi-
dence as to what sugars are absent and more quantitative data in regard to the
ones present are much to be desired. The reviewers state that there is strong
evidence that sugars are the first definitely known products of the assimilatory
process, starch probably being a secondary product. Although most workers
regard cane sugar as first, there is no satisfactory evidence that the hexoses may
not be first. The mechanism of translocation is complex, depending upon
differences of enzyme concentration, and possibly upon permeability changes,
the nature and causes of which are at present largely unknown. The available
data on energy relations are dealt with under three heads: (1) quantitative
determinations of materials produced and their heats of combustion, (2) meas-
urement of both radiant energy and heats of combustion, (3) assimilation
1917] CURRENT LITERATURE 519
power of light of different wave lengths. Under (1) two methods of estimating
the products of carbon are discussed: (a) increase in dry weight, and () amount
of CO. taken in. The reviewers conclude that if the dry weight method can
be made more accurate, it should not be lightly abandoned. If we assume with
BRowNn and Escomse that the heat of combustion of all products of assimilation,
is the same as that of glucose (3.76103 gram calories), we shall fall into a
considerable error, as is indicated by the following values for other substances
present in leaves: sucrose 3.99103, starch 4.110%, cellulose 4.210%. If
oils are present, the error in this assumption would be still greater. Actual
determinations of heat of combustion made by other workers on the products
of assimilation in the leaves of various plants give values varying from 4.4 103
to 5.2X103 gram calories.
Quantitative measurements of radiant energy in relation to the leaf are
based on the assumption that the total radiant energy falling upon the leaf is
disposed of in the following ways: (1) reflection from the leaf surface, (2) carbon
Le (3) transpiration, (4) transmission through the leaf, (5) thermal
epee and EscoMBE (1905) disregard (1) in their calculations. The
reviewers believe that this is not negligible, since even a black cloth may reflect
I per cent of the radiant energy incident upon it. PwuRIEWwITscH (1914) has
estimated (2) in a few cases by measurement of the increased heat of combus-
tion of the leaf per unit area. His highest value was 2.6 and his lowest 1.3 per
cent. On the basis of these he calculated other cases, getting as high as 7.7
per cent. Brown and Escomse calculated (2) by assuming that one gram of
absorbed CO, is equivalent to 0.64 gram of dry matter formed, and that the
heat of combustion of the products of assimilation is 3.76103 gram calories,
The accuracy of these assumptions is not confirmed by measurements. Their
computed values vary from 0.42 to 1.66 per cent. All of the evidence at
hand thus indicates that only a very small percentage of the radiant energy
received by the leaf is actually used in carbon assimilation. It might be
expected that the proportion of the sun’s energy used in assimilation would
vary inversely as the intensity of the illumination. This expectation is not
justified by the experimental data, and it is clear that we must look for some
other factor on which no data are given. The reviewers point out here a
case of lack of correlation of effort by investigators. If Purrewrrscu had
taken cognizance of BLAcKMAN’s researches, his experiments (although
regarded by Purrewitscu himself as preliminary) might have yielded results of
much greater significance. The energy used in (3) was arrived at by Brown
and Escomse by determining by weight the amount of transpiration and
calculating the energy used from the heat of the vaporization of water at that
reviewers vary but little, the highest being 35.32 and the lowest 35.28 per
cent. It is evident that (5) will usually have a positive value, since the
520 BOTANICAL GAZETTE [DECEMBER
temperature of the leaf is usually higher than that of the air. If, however,
the temperature of the leaf falls lower than that of the air, the leaf will gain
energy from the air, that is, thermal emission will be negative. Brown and
EscoMBE’s values for thermal emission are based on the same set of experiments
as the data quoted under (2), (3),and (4). They areall positive. The smallest
one is 6.0 and the largest is 54.60 per cent. Brown and EscomBe were the
first to attempt to obtain a complete balance sheet for the leaf in regard to
energy. Further quantitative data correlating the work of BLACKMAN,
BRown and EscomBe, and PurIEwItTscH are greatly to be desired. We still
have no reliable data on which any conclusion can be based as to the relative
efficiency of the rays in the different portions of the spectrum.
e reviewers mention the early work, indicating that the maximum
assimilation takes place in the red part of the spectrum and that there is a
secondary maximum in the blue-violet end as being now of only historical
interest, since the methods of measuring energy were unsatisfactory and the
measurements of assimilation were crude.
The work of Knrep and MinbeEr (1909), indicating that blue and red light of
the same intensity produce the same assimilation and that the green light is
incapable of producing assimilation, is rejected because they give no data
relating to any factors other than light intensity, hence some other factor may
have been a limiting one. They also reject TIMIARIZEFF’S (1903) data on
the absorption of energy by chlorophyll, since he worked with alcoholic extracts,
which must have contained less chlorophyll than impurities. The work of
Brown and EscomseE on the absorption of radiant energy by the white and the
green portion of a leaf of Negundo aceroides is also rejected, since it is considered
unfair to assume that the conditions in the green and the albino parts are the
same except for the presence of chlorophyll. Werr1cERT’s (1911) conclusions
on the efficiency of the assimilation system are considered unreliable, since they
are based on the work of Brown and EscomBe just mentioned.
The reviewers introduce their discussion of theories of carbon assimilation
with a sweeping condemnation of theories, making the point that those who
have contributed the most valuable data on this subject have not suggested
any theories. They cite DE SaussurE, SAcHS, PFEFFER, and BLACKMAN as
examples. They might possibly have added SpoenR to the list, but they
could not have added WittstAtrer, since his data on the pigments of the
green leaf are certainly very eS pas considerable space is given in their
review to the discussion of his theor
course blind following of a fa does not lead to progress, and the
desirable attitude is that of seeking for facts regardless of their bearing on
any theory, but to assume that none of the workers (except SPOEHR) have
been influenced by dissatisfaction with the theories that have been advanced
seems unwarranted. It is not the right use of scientific imagination that is to
be condemned, but the acceptance of mere imaginings as facts. JORGENSEN
and StiLes, of course, are quite right in their condemnation of whatever
1917] CURRENT LITERATURE 521
tendency there may have been in textbooks to present BAYER’s hypothesis as
representing facts.
ey discuss the theories and suggestions of four men: (1) the well known
theory of BAYER involving formaldehyde as an intermediate product; (2) the
suggestion of vAN’T Horr that assimilation consists of two parts, a photo-
chemical reaction and an enzyme reaction; (3) SIEGFRIED’s suggestion that
carbon dioxide may form carbamino groups with the protoplasm of the plant
cell and that the photochemical reaction may then occur in a complex carbon
compound; and (4) WiitstATrerR’s theories which, so far as they are new, are
regarded by the reviewers as rather wild, the most reasonable one suggested
by him being merely a repetition of SIEGFRIED’s suggestion.
In the end it appears that we have at present no satisfactory theory of
the changes that take place between the entrance of CO, into the plant and
the production of carbohydrates.
Although deploring the lack of coordination among the various workers,
and the tendency of botanists to accept without question the suggestions of
physicists and chemists as to the nature of plant processes, the reviewers con-
clude that plant physiology is developing into an exact science, utilizing the
experiences of the fundamental sciences, physics and chemistry, but having
working principles and methods of itsown. That it will thus be of great service
in plant production requires no prophetic vision.—GrEorGE B. Rice.
Studies on oxidases.—In connection with his work on plant oxidases,
BuNzELL’ has published results of an investigation of the effect of hydrogen-
ion concentration, Ch, on oxidase activity. Using his own simplified oxidase
apparatus to measure oxidation and the gas chain to measure hydrogen-ion
concentration, he finds that the oxidase activity of several kinds of material
from potato tubers is completely inhibited by a Cn of 2.0-2.8X10—4. The
various concentrations were obtained by adding sodium hydroxide and acetic
acid in various Ae ng or either one alone, to mixtures of the plant
material and pyrocatec
It is worth noting ae that the two together constitute a true buffer solu-
tion capable of maintaining a fairly constant hydrogen-ion concentration, but
that neither one alone suffices. Consequently, if there is a tendency for the
acidity to increase in the Bunzell apparatus, as suggested by Rose® in 1o15,
conditions are not comparable in the different mixtures. Those containing
the true buffer solution will have practically a constant Cp throughout the
course of the experiment, while those containing only sodium hydroxide or
acetic acid will have a Cp which is larger at the end than at the beginning. The
7 BuNZELL, H. H., The relationship existing between the oxidase activity of plant
juices and their hydrogen-ion concentration, with a note on the cause of oxidase activ-
ity in plant tissue. Jour. Biol. Chem. 28:315-333. 1916.
8 Rose, D. H., Oxidation in healthy and diseased apple bark. Bor. Gaz. 60:
55-65. 1915.
522 BOTANICAL GAZETTE [DECEMBER
latter condition holds true also for the controls; containing only water, pyro-
catechin, and plant material. Furthermore, if the Ch changes during the
experiment and only the initial couichateation is determined, as in BUNZELL’S
work, no very accurate conclusion can be drawn as to the effect of this factor
on oxidase activity.
BunzELt finds the inhibiting concentration for tulip tree material to lie
between 1.58 and 5.02X10~3, and for the magnolia between 3.5 10~3 and
8.91X10—4. He considers that his results show “that the acid sensitiveness
figure is a rather fixed number for any particular genus.”’ He says also that
it even seems “that the acid sensitiveness constant is the same or nearly the
same for different genera (tulip and magnolia) of the same family (Mag-
noliaceae).” An analysis of his table III shows in general that the less the
natural acidity of the plant material the lower the Cy necessary to cause total
inhibition of its oxidase activity. This relation does not seem to hold in all
cases, possibly because the various degrees of acidity used were too far apart to
establish the inhibiting concentration with any great degree of accuracy.
If further work should prove such a relation general, new force will be
added to the suggestions of BUNZELL and others that there is a distinct oxidase
for each plant or group of closely related plants; not necessarily because they
are protein in nature, however, as BUNZELL supposes. They may resemble
each other in plants of the same family; they may show various properties of
proteins, such as denaturing by acids, alcohol, and heat, and still be something
quite different from proteins. BAYLIss suggests, on the basis of work by BACH
and Cuopat and others, that oxidases are merely some form of iron copper ot
manganese kept in a disperse condition by various colloids. If these colloids
are proteins the action of acids, for example, removes them as dispersing
agents and allows the oxidases to precipitate. As a result of absorption, the
two may come down together as a single precipitate which gives both protein
and oxidase reactions without ever having existed as a real compound in the
living plant. Such a hypothesis, however, fails to apply to peroxidases, for
these, according to BeHrinc, Aso, and BacH and CHoDAT, are very little
affected by heat. Bacx and Cuopar also found that horseradish peroxidase
when carefully purified contains no iron or manganese.
In connection with BuNzELt’s “acid sensitiveness figure,” the question
arises whether the inhibition he noted was all due to acidity. When a buffer
solution of any sort is used to establish a definite hydrogen-ion concentration,
elements are added which in the quantity used may be entirely foreign to the
plant and productive of anomalous results. Illustrations of this are seen in
Bunzetr’s table III. For example, extract of potato peeling with a natural
Cn of 1.021076 (no buffer solution being present) caused 22 per cent more
oxidation than the same extract when a buffer solution was present and the
Ch practically the same (1.04X10~®). Even more marked are the results
with potato sprouts, for with the Ch just about the same whether the buffer
solution were present or not, they gave 16 per cent more oxidation without
1917] CURRENT LITERATURE 523
jt than with it. The data presented for ‘‘tulip tree leaves 1915” and “scaled
tulip tree buds” show that when the solution in the oxidase apparatus had the
natural reaction of the plant material, the oxidations were respectively 6.6
nd 12 per cent greater than when the Cn, established by a buffer solution, was
actually less than the natural Cn. In such a case it seems evident that some
factor other than the hydrogen-ion concentration was effective as an inhibitor.
The possibility that other ions play a part is indicated by work now being
carried on by KRAYBILL and the writer.
The paper concludes with a brief review of the evidence, obtained by
BUNZELL and others, of an increased oxidase activity in the leaf tissue in the
case of physiological disturbances, and the possible meaning of such an increase.
No mention, however, is made of work by RosE on healthy and diseased apple
bark in which it was shown that there is a much greater oxidase activity in the
latter, sail with a lower hydrogen-ion concentration.
9 in a paper published about the same time as BUNZELL’s, puts the
inhibiting Ch for oxidase of potato extract at 5.5x10~4 (slightly higher than
the 2.0—2.8X10~4 found by BUNZELL), and for that of Red Astrachan apples
at 5.0—7.0X10—4. His statement that these concentrations are much lower
than those given by previous investigators fails, however, to take account of
BERTRAND’S report’? in 1907, that a n/s5o00o solution of sulphuric acid (Ch=
51074) completely inhibited oxidation by sap of the lac tree. REEp’s results
would have meant more if he had measured oxidation by the BUNZELL appa-
ratus rather than by the relatively inaccurate method of noting color changes,
even though the BUNZELL apparatus, because of the poorly understood effects
of hydrogen-ion and other inhibitors, leaves much to be desired in the way of
accuracy,
One point is well made in this paper, namely, that plant extracts have an
acid absorbing power which must cause inaccuracy in interpreting results
obtained by adding buffer solutions to them if such results are not checked by
careful determinations of the cab ig al ape ranean He found that
when a given volume of 0.01 molar HC added to an equal volume of
potato extract, the hydrogen-ion ican rg which should have been
5X107—3 if the potato extract acted like water, was actually only 51074,
This decrease in acidity he thinks is due to riecteise present in the extract as
well as other amphoteric electrolytes, including probably phosphates and
carbonates.
It is unfortunate, to say the least, that the authors of these papers have
failed to cite adequately the literature pertinent to the phase of the subject
with which they are dealing. Each has made a definite contribution to our
9 Reep, G. B., The relation of oxidase reactions to changes in hydrogen-ion con-
centration. Jour. Biol. Chem. 27: 299-303. 1916.
© BERTRAND, G., Bull Soc. Chim. France 1:1120. 1907.
524 BOTANICAL GAZETTE [DECEMBER
knowledge of the factors affecting oxidase activity, but the true value of this
contribution would have been better shown by a fuller reference to other work.
STLE and BUCKNER" report experimental proof that phenolphthalein
can be oxidized in the living plant. This they take to mean that free active
oxygen is present in the tissues, apparently overlooking the possibility that
combined oxygen might have caused the results observed. The reagent used,
on oxidation, yields phenolphthalein, which is easily recognized by the pink
color it gives with alkalies. When this test was applied to stalks of Indian
corn which had been injected with the reagent, the pink color was found local-
ized in the fibrovascular bundles of the stem and leaves. It was not found in
the tassel, although lower down, close to the point of injection, there had been
some diffusion into the cells adjoining the fibrovascular bundles. Similar
results as to place of oxidation were obtained with okra.
The method here used offers a means of attacking the problem of oxidation
in plants which should yield other valuable results if further developed and
applied to a wider series of plants. It would be worth while to try whether
phenolphthalein can be oxidized in the living plant when used in neutral or
acid solution, and if so whether the oxidation is localized in particular cells
or tissues. Such a test would allow for the effect of reaction (acidity or alkalin-
ity), a factor known to be of great importance, not only in oxidation processes,
but also in other processes carried on in living tissues. The effect of reaction
might also be studied in acid fruits and in tissues affected by “physiological
diseases’’ or by diseases due to bacterial or fungus parasites. In several cases
such tissues have been found to be less acid than healthy ones, but little is
own concerning variations in reaction within the tissues themselves.—
D. H. Rose.
Experiments in girdling.—A contribution by HrB1No” is of interest both
to plant physiologists and horticulturists, since it will aid in furnishing a more
definite chemical basis for the interpretation of the behavior of girdled plants.
In the past there has been no lack of references to the accumulation of elabo-
rated foods above the girdles; it is certainly worth while to have some definite
determinations of these compounds and their relative quantities.
Five types of girdling were tried on Cornus contraversa Hemsl. These con-
sisted in (1) removing a complete ring of bark, (2) removing a complete ring of
bark and some of the wood, (3) removing half a ring of bark, (4) removing half a
ring of bark and wood, and (5) boring completely through the wood. The
wounds were left unprotected. The last three methods of treating the material
resulted in responses similar to the untreated controls in nearly all cases.
The genera] external results noted are those commonly recorded in girdling
experiments. The main interest of the present paper centers in the presenta-
Kastte, J. H., and Buckner, G. Davis, Evid { the action of oxidases within
the living plant. tone Amer. Chem. Soc. 39:479-482.
HIBINO, Sutn-Icut, Effekt der Ringelung auf ie eae bei Cornus
controversa Heil: Jour. Coll. Sci. Imp. Univ. Tokyo 39:1-40. pls. 1, 2. 1917-
1917] CURRENT LITERATURE 525
tion of material which may aid in an explanation of the cause of these condi-
tions. Unfortunately the experiments are limited and the analyses of the
nitrogenous compounds are not sufficiently complete to furnish any sort of
basis for judging what réle they may play. The data on the carbohydrates,
however, are of considerable interest. In studying the effects of girdling on
nutrition in general, at least three of the many points concerned in growth must
be considered: (1) a possible modification of the intake of nutrients by the
roots; (2) the synthesis of products from these compounds and those resulting
from photosynthetic activity; and (3) whether these compounds are stored
or utilized. We are given some light on the third point only. It is a fair
question to ask whether the ability of the roots to take up salts is not as pro-
foundly modified by the character and quantity of the organic nutrients in the
parts above ground and with which such salts may be combined, as it is by the
so-called starvation effects brought about by cutting off the supply of organic
nutrients from the tops to the roots. Girdling could pring about _ en cet
Situations. The question arises as to why the
the girdles. As commonly stated, this may be due to the fact that these
products are held from passing into the roots. There is little evidence which
would show that it may not also be due to a deficiency of mineral nutrients,
particularly nitrates, to aid in their utilization in forming other compounds
or growth. study of the ratios of carbohydrates to moisture, nitrogenous .
compounds, and other mineral nutrients in their relation to the entire phe-
nomenon of growth is greatly to be desired. While this situation is not
dealt with by Hrsrno, his results and those of several previous investigators
furnish ample encouragement to warrant investigation.
The increase in anthocyanin accompanying an increase in reducing sugar
confirms the findings of previous workers with other plants. The yellowing
of the foliage above a girdle is a usual condition. That this should accom-
pany an increase in carbohydrates is interesting. It is unfortunate that no
analyses of the nitrogenous compounds in the leaves are available. Lacking
such determinations nothing can be said concerning their possible relationship
to the carbohydrate situation, nor the moisture situation. The fact that the
percentage of moisture in the leaves is lower when carbohydrates form a higher
percentage of the weight might be expected when the moisture holding capacity
of these compounds is considered.
The single quantitative determination of the reserve materials in the twigs
in midwinter is not sufficient for any general conclusions. Again, it is unfor-
tunate that all the nitrogen is computed as protein. It is more than likely that
all of it is not, and quite probable that the several forms of nitrogen may exist
in different proportions in the several lots examined. A quantitative analysis
at the time of active vegetation would have been even more significant regard-
ing the influence of the several substances on growth. Striking as are the
differences in the several lots, the results cannot be interpreted with certainty
unless compared with figures for similar parts at several periods during the
526 BOTANICAL GAZETTE [DECEMBER
year. Whether the differences shown by the bark and wood girdled material
may be accounted for by a decreased moisture supply in the latter is an open
question. It is interesting to note, however, that many plants grown with a
deficiency of water do show an increased tannin content.
e it is impossible to draw broad conclusions from the results pre-
sented, the work constitutes a genuine contribution toward a more nearly
complete knowledge of the causes of the responses following girdling, and adds
to the available information on the entire problem of growth. In any future
work it would be particularly desirable to follow the nitrogenous compounds
and mineral nutrients as well as the carbohydrates, more especially with a
view toward the determination of the ratios of these various substances in
relation to the observed responses.—E. J. Kraus
Imbibition—MacDovucaL® and MacDovucar and Spornr™ are doing
work on the effects of acids and bases on imbibition of water by plant tissues
and plant gels that promises to be the most significant contribution in this
phase of plant physiology that has been made for some decades. Practically
all of the work on the effect of acids and bases on the amount of swelling and
force of swelling of gels and on the viscosity and osmotic pressure of sols has
been done on the amphoteric protein gels. For these it seems well established
that the iso-electric point (the reaction at which the particles are without a
charge) is the point of minimum swelling, force of swelling, osmotic pressure,
and viscosity, and that forcing the ionization of the gel or sol either to the posi-
tive by addition of an acid or to the negative by the addition . a base increases
the swelling, osmotic pressure, and viscosity very markedly.
MacDovceat and Spornr find that both base set acid aii (n 0.01)
decrease greatly the swelling of agar plates and to a less degree of Opuntia
tissue. In fact, Opuntia tissue acts more like mixtures of gelatine and agar
than it does like either gelatine or agar. These results suggest that in con-
trast to the protein gels and sols, the point of maximum swelling, viscosity, etc.,
in agar is the iso-electric point and that the positive agar due to acid addition
or the negative agar due to base addition shows a lowering of these characters.
In this connection it is to be regretted that the H+ concentration for the iso-
electric point of agar has not been determined. It is also desirable to know
the behavior of various other carbohydrate gels and sols (mucilages, pectic
materials, gums, etc.) to see whether this contrast in behavior is a general
difference between the protein and carbohydrate gels. It seems that plant
physiologists have generally assumed that the laws of behavior of protein
% MacDoveat, D. T., Imbibitional swelling of plants and colloidal mixtures.
Science 44:502-505. 1916.
™ MacDoveat, D. T., and Spornr, H. A., The behavior of certain gels useful in
the interpretation of the action of plants. Science 45:484-488. 1917
*s Hoper, R., Physik. Chemie Zelle Gewebe. 329-338. 1014.
1917] CURRENT LITERATURE 527
colloids hold for all hydrophilous colloids with which they have to deal,
protein as well as carbohydrate. This work seems to make evident the error
of such a general assumption.
A quotation from the last paper gives the author’s view of the physio-
logical significance of these results. ‘‘The general identity of constitution
of these colloidal mixtures and of cell-masses, and the obvious similarity of
their behavior, together with newly determined features of carbohydrate
metabolism not described in this paper, make it possible to correlate more
closely the processes of imbibition, metabolism, and growth, and on the bases
of these interrelations, to pherpret ares enlargement and incidental varia-
tions in volume and size of organs.””’ No doubt many will differ from a state-
ment in another part of the paper that amorphous carbohydrates form a very
important part of the plant protoplast. There seems little evidence that
carbohydrates are constituents of the protoplast they generally appear as
discrete particles of micronic size and not in intimate mixtures with proteins
and distributed in particles of submicronic or amicronic size, as must have
been the case in the agar gelatine 2 i with which the authors worked.
late we are coming to know that amorphous carbohydrates of the walls
and intercellular spaces have sudiahe physiological controlling action.
is is especially true in s. is work is very suggestive in this connection
so.
This work may have a very important bearing on the daily transpiring
power of certain of the cacti as found by various workers in the Desert Labora-
tory. In these there is apparently no stomatal regulation, and the lowest
transpiring power is during the day. This corresponds to the daily change
in acidity. The time of low transpiring power is the time of low acidity, when,
according to the findings of MacDovucat and Spornr, the gels of the tissues
will have the greatest power to take up and hold water. With this no doubt
there will be a rise in viscosity. These physical conditions will all tend to lower
the rate of movement of water toward the intercellular spaces and to lower the
vapor pressure within those spaces. This in turn will lower the rate of outward
diffusion. This suggested relation needs careful investigation. On the basis
of the behavior of protein gels the daily variation in the transpiring power of the
cacti was not intelligible. This work should be a great stimulus to much work
along similar lines —Wa. Croc
Taxonomic notes.—BritTon,” in continuing his studies of West Indian
plants, has described new species in Cleome, Chamaecrista (3), Leucocroton (3),
Passiflora (3), Rondeletia (10), Eriocaulon (3), Dupatya, Pilea, Ichthyomethia,
% Britton, N. L., Studies of West Indian plants. IX. Bull. Torr. Bot. Club
44:1-37. 1917.
528 BOTANICAL GAZETTE [DECEMBER
Castelaria, and Stenostomum (2). There is a synopsis of the species of Chamae-
crista in the West Indies (31 spp.); of the Cuban genus Leucocroton (7 spp.);
of Passiflora in Cuba (21 spp.); and of Rondeletia in Cuba (35 spp.).
Dr
CANDOLLE,” in a study of specimens of Meliaceae from Central America |
and Panama sent by the United States National Museum, has described 9 new
species in Guarea and 2 in Trichilia.
Hepccock and Hunt® have described 5 new species of Peridermium on
pine needles in the eastern United States
RN, in a monograph of the North American “sedge rusts,” recognizes
19 species of Puccinia, 3 of which are described as new
NELL,” in continuing his studies of our southern plants, has presented
the genus Chamaecrista as represented in the United States. He recognizes
13 species, which include 3 new species and 2 new combinations.
WaceEr* has published a list of the mosses of South Africa, which for the
first time brings together all the known mosses of South Africa. The list
includes 846 species in 160 genera, representing 37 families. The names of
27 new species, representing 23 genera, are also included, one of the genera
(Physcomitrellopsis) being new. These will be described and published later.
ILLIAMS,” in reporting the mosses obtained on a collecting trip in -
ser te ae ee ay October 1903 to August 1905, lists 2
species in , 27 species and 3 agi hades,
y Sear casmnaloain are desis as new.—J. M
Endosperm color in maize.—In crosses between California Golden Pop
maize and a white endosperm ey obtained from Haace and Scumipt under
the name Zea Caragua, WurrE* finds white dominant. These results are
interpreted by assuming the presence of an endosperm suppression factor A
in the Zea Caragua in addition to the usual color factor y. , This new primary
factor affecting endosperm color raises the number of such factors to three;
in addition there are numerous secondary factors.—E. M. East.
DeCanbotte, C., Meliaceae Centrali-Americanae et Panamenses. Smithson.
Miscell. Coll. 68:no. 6. pp. 8. 1917.
* Hepccock, Gro. G., and Hunt, N. Rex, New species of Peridermium. Myco-
logia 9:239-242. 1917.
? Kern, Franx D., North American species of Puccinia on Carex. Mycologia
9: 205~238. 1917.
* PENNELL, Francis W., Notes on plants of the southern United States. II.
Bull. Torr. Bots Club 44:337-362. 1917.
* Wacer, H. A., A check list of the mosses of South Africa. Publ. Transvaal
Museum, Pretoria. pp. 20. 1917
* WILLIAMS, ingens S., Philippine mosses. Bull N.Y. Bot. Garden 8:331-378-
pls. 171-174. 19
3 WHITE, be aks E., Inheritance of endosperm color in maize. Amer. Jour.
Botany 4:396-406. 1917.
=
GENERAL INDEX
Classified entries will be found under Contributors and Reviewers.
New n
and names of new genera, species, and varieties are printed in bold face ses
synonyms in #talics.
A
Abutilon, resistance of seed coats to in-
take of water 166
by Hoang 3
Addiso mi
keropeeo
Algae, of Michigan
Alkalies and ans absorption 346
um 84; permeability in 509
Alnus Ferdisandl Cohecett 147
Amani
Amsinckia 446
Andrews, E. F. 497
rasoane) 79s eurycarpa 81
Anthoc
Apog: ae ih aceores and Osmunda
435
Appleman, C. O. 349; work of 351
bis 440
Arber, Agnes, work of 350
Archegonium of Cath:
W. R. G.
peeiogy 82: work of 256
Atkinson, G. F., work of 340
B
Balsamorrhiza, resin secretion in 441;
connata 33; cornu illeniana 30;
frondosa outa 343 | Holwasi 395 hu-
33; Langlassei 24; leptoc
22; mollifolia 21; Palmeri
, 29; sends:
lausensis 26 Figen 35; sambucifolia
40; Seemann 27; —_ osa 35; tenui-
secta 30; tipartin
Blackburn, Kathleen 3. work of 350
Blake, S. a ¥ seonk ol-a9p
Blandibra
Boerker, RH j: apa of 351
529
n, E. Pe Bg of 257
seein:
sourquin, Hide 426
sovie, W. T., — of 342
pase: F. O., work of 347
ay, W.L., reek of 88, 352
reazeale, J: P., work of 346
rickellia
uckne r, G. Dye work of 524
ulbiferous fungi 265
nzell, H. H., work of 521
tae See ’ work of 2 257
surns, =e Py work of » 264, 352
surt, E. A., work of 8
Seesd Weed head benad: Ieeal bi
ie
Calcium ce ae of soil 347
Caldwell, J. S., work of 87
Cambium in m monocotyledons 350
Campylogramm
Carbon steitaiiation aed
Car e 261
arex 84, 261
Cassia 1
aie we a" of 1
Cephalanth
hamaecrista 174, bes
mberlain, C. I
Cc
Be
Cc hinese seo 70, I as
Ch osomes, number of 171
Cc
cS
Co
me s leaves, mottling i in 343
eome
ker, Ww. ©, work of 439
Colo: ills vegetation in 353
Coniferous fevestn: oe ee in 149
coun An drews 497; Ap-
480; i
Cierabinicin, c 27s Cae M. T.
53°
345; Coulter, J. M. 83, 87, 255, 260,
349, 343, 347, 359, ie "352, 439, 516,
527; Coulter, M. C. 263; Crocker, W.
82, 84, 168, 172, 343, 344, 346, 347, 349,
526; D E. 166; Dupler, A
87, 88, 176, 253, 254, 262, 263, 264, “85,
348, 350, 351, 3525 Harris Laura 318;
sal ~ Ws 1935 tris, J. A. 285;
Harvey, R. B. 342; Hasselbring, H.
' 169, 176, 262, 337, 3493 Hotson, J. W.
265; Krau s, E. J. 524 ; Kraybill, H. R.
423 eiernadg dN. ys Long, W. H.
S73 ir, J. B. 330; McNeill, J.
318; Macbride, J. F. 79; MacCaughey,
V.8 : M.S. 177;
9, 386; Markle, ‘ re,
B.149; Payson, E. B. be Record, S. J.
437; Riddle, L. W. 513; Rigg,
438, 516; Ro an $F ra oi. Rumbold,
Caroline 250; Sawyer, M. Louise 159
Sawyer, W. H., Jr. 206; Schneider, C
70,137; She Shull,
Wuist, ra D.4
Cook, M ee
Cordia
Conooky tani 440
Cosmos Landii 29
Cotoneaster he Hero 70; Vernae 71
Coulter, J. M. 83, 87, 255, 260, 340, 343,
347, 35°, 351, are 439, 516, 527
Coulter, M. C. 2
Crocker, W. os, ay 168, 172, 343, 344,
346, 347, nt 526
Crown gall 33
Culpepper, e W., work of 86
Cuma ola 440
Curtis, K. M., work of 352
Cyanea 261
D
Darwin, F., work of 172
ed cake ae — of 349
DeCandoll ce an of 528
Derbesia
Desert Plats, root systems of 177; the
variable
Diehl, W. wo ens of 170
iseases, fruit
Dodecatheon 44
Doles Mis ¢ é. E., work of 340
Duar B. M. work of 169, 170, 176, 349
Dupatya 1
ery A. W. 1
Dyes, effect on Endothia 250
INDEX TO VOLUME LXIV
[DECEMBER.
E
East, E. M. 5
Enc meee ny mutation theory ni
Enc ophiylloides hd 5
Endophyllum
Endosperm tick ta ize 528
Enc — parasitica, ge oe of dyes on
Epiphytc — anatomy of 352
Era
Erigeron
Eri ns . ° honk of 169
174
i . of 345
Evans, A. W., work of 260,
Evaporation pa from Galt. Coast 318
Everett, A. E., 7 256
Extinction, i in ‘Hawaii
F
Farrow, E. P., — of 263.
Fernald, "M. 1 work of 33, 261
F “ea phylogeny 0 of 3
Ficu
eee; in ccceacin of nia eer oie 497
Fomes, peculiar spore distri 261
‘00
Free, E. E., work 0
Fruit classe: 2543 seek of fungi on 86
Fuller, G. D. 85, 87, 88, 176, 253, 254;
262, 264, 347, 348, 350, 351, 352
Fungi, enzyme activity of 175
G
Galls 3
ace of Taxus canadensis 115
ano, Laura
ra 31
Gardner , N. L., work of 44:
work of ee Oe, 34°
Grasslan eath 2
Greenman, J. M., oti a 83, 175
Gulf ‘Conit, evaporation ion records from 318
1917]
H
Haas, A. R. Dak ted sed se
Hagstrém, % O.,
Harper,
Harris, J A. 28 5
Harvey, R. B. 342
Harr tris, J. A., work of 264, 345
Hasselbrin, g, H. oe 176, 261, 337, 3493
work =: 173, I
Hawaii, =e ax of 89; vegetation of
lava ows 386
Hawki ig te work be 86, 173, 174
Heath ou grassland 26
Hedgc aia NG G., work ~ 528
Herberta
Hesler, L. z ‘Manual of fruit diseases”
254
Spina S., work of 524
Hier
Hildebrandt, _F. M., w
of 526
Hunt, N. R., work of 528
I
Ichthyomethia 174
Imbibition 526
Ishikawa, M., work of 171
J
n, C. A., work of 343
restry 262
K
oeaard { ies vo of 256
> > we
sacri L., work of 344
Koidzumi, G., work of 341
Kraus, E. J. 524
Kraybill, H. R. 42
INDEX TO VOLUME LXIV
L
ae J. V. 285; work of 345
174, 528
Leuc
: Tichéda, coy 264
Li
um
n, B. a wo
Lloyd, T t., “The Ie of inland waters”’
2
Long core 2 gare of 176
Long, W. H
M
McBeth, I. G., work of 3
McClendon n, J. RF. Physical chemistry of
vital phenomena” 438
McNair, igs 330
M - 318
Macbride, y. F, eet work of 440
acCaughey, V. 89, 386
Martins in T a i of 526
e, K. K., ’ work of 84, 261
Maize, endosperm color in 528
Mallison, H., work of 256
Marattiaccac, mycorhiza of 350
Marchantia 260
Markl : MS. 7
Matz, J., wor 171
Meinecke, E. P Ps work of 3
woe “ion f Cen tal” aA ceed and
a 52 28
Meliola t types, Spegazzinian 421
Mertensia 440
Microchaete 83
ilti °
onocotyledons, eT in 350
Monocotyledony 34
Moore, B. 1
Moore, S. LeM., work of 341
Morus 34
Mosses of Sou rica 528
Mottling in citrus leaves 343
Mucor 341
Murrill, W. A., “North American flora”’
516; work of 255
5
and endemism 263
Mycorhiza of Marattiaceae 350
N
Nagai, I., work of 260, i
Nakai, T. work of 15) 3
Needam nS h re “The ‘ite of inland
se
waters ud
Neobertie
Nesareniin ¥ Holwayi 67
)
532
New York, Le pion of 352
Nitrogen, = 349; sstatioih of semi-
arid so
North Miran flora 255, 516
O
Oenothera 175
Olive, E. sti nig of 175
Cnneiucdie
Organic nutrition of plants
Osmotic re in PPS ne host 345
Osmunda, a apogamy i 435
Otis, C. H., work of 88, 352
Oxidase Ses 5
r
ie tere a oe 273; byssina 270;
pallidula 268
; nigra 275;
Pupasite me pies osmotic pressure in 345
ioe? ae
Passiflor
eee icky ie
Payson, E. B. 795 work e 341
Peltier, = L., work of 1
Pennell, F, W., Tata of oes, 528
w method of studying
306; of cal wails of Allium 509; of pro-
ete dh 3
Petalostemum 440
Phacelia
Phaes
Phegopte Say
Sgeoatiet phe aimed of 206
Phot rain = of dust on 349
Somat: trichum
t, F. L., work of 351
Pilea 17
Pine, Hepa of Virginia and the wera
—— of longleaf 49
Pis tillart
Plant a iay. Se to 168
Platanus, w 480
Po lakiastru 175
Pollen cakes and i ia es ak Iris 159
Polygonatum 34
Potamogeton ae
ease iy of 230
Prunus latidentata trichostoma 72
Pseudopohlia 528
Puccinia 528
INDEX TO VOLUME LXIV
[DECEMBER
Pulling, H., work of 168
Pyrenothrix nigra 513
Quercus alba, ray tracheids in 437
R
nales one anatomy of 3
ae 64
Re Jason in ucts es 437
ecor A377
eh G. B., work of 523
en , work of 175; 261
Resin pects
Respiration 351;
4
Reviews: Atkins’
] rrhiza 441 _
effect of sin sre dioxide
“Researches in plant
H
Romeli, L.,
Rondeletia 54,53
t, of Balsamorrhiza 4 52; rot of Texas
eee systems of desert plants 5
R 84; landulosa 75; Maire
plurijuga 743 — yunnanensis 77
Rose, D. H. 521
Rubus ‘eatictan 73
Rudbeckia
Rumbold, Caroline 250
Russula 440
Rydberg, P. A., work of 84
5
Salix Balfouriana 137; brachista 144;
caloneura I41; dibapha 146; Faxon-
iana 143; tiana 139; ener
Guebrian
rosa 142; tenella 137; wolohoensis 14
1917]
Salt, absorption and alkalies
fire-h olding capacity of tobacco 4
and dunes of Michigan 348
anford, , Wo
chneider, C 70, 137
eedling epneted of Ranales 350
enecio 83,
equoia, iossil “rom Japan 352
herff, E. E. 2
hibata, K.. work of 256, 260
hibata, Y., ork of 256
hull, C. ae 86, 344, 351
ipane
Mare
mith, E ¥., his of 337
ith, ork of 341
mit
oil, calcium compo ounds of 347
u vegetation ig 85
permatogenesis, Tris
piro
28 staged 8 526
pore distribution
tandley, P. C., nieces 255, 440
tarch formation in Z ygnema 426
t Balsamorrhiza 455
Stenostomum 174
oe —
Ss, Fo ke 2
bay R. fee work. o 350
tiles, W., ork of 5
tomatal regulation ae
tropharia
weet potatoes ee storage 173
ycamore woods, North American 480
PA TATA rA
é &
' Tapetal nuclei, wandering 351
Taxus canadensis sis, gametophytes of 115
Ea bh oe and viability
Tephrosia 175
Tidestrom, I., work of 8
ioe fluids, carcecbic determinations
285
hacen fire-holding capacity of 42
of 168
Tottin gha am, W. E., work
Transeau, E. N., work of
, W.G., k of a,
Travis, W wor
Trelease, S. F., work of 16
Trees, of Pennsylv sah 35: of Vermont
352; tolerance of 2
INDEX TO VOLUME LXIV
533
3465 | and Trillium
83
Tropical vegetation 87
Truttwin, H., work of 256
Turriculs 440
V
ge? Aide ers C. R. W. K., work of
Veronica 440
Vestal, ve Gers
Viability and temperature 34
Viburnum, calvu seh 78;
dricum scadelfosints 77
cylin-
W
Wager, H. A., work of 528
Waggon er, HL a work of 344
Weil
Williams
Willstitter, R., work 0
Woodhead, Z i W., “