UTRICULARIA (continued).
Utricularia montana—Description of the bladders on the subterranean
rhizomes—Prey captured by the bladders of plants under culture and in a
state of nature—Absorption by the quadrifid processes and glands—Tubers
serving as reservoirs for water—Various other species of
Utricularia—Polypompholyx—Genlisea, different nature of the trap for
capturing prey— Diversified methods by which plants are nourished.
FIG. 26. (Utricularia montana.) Rhizome swollen into a tuber; the
branches bearing minute bladders; of natural size.
Utricularia montana.—This species inhabits the tropical parts of South
America, and is said to be epiphytic; but, judging from the state of
the roots (rhizomes) of some dried specimens from the herbarium at Kew,
it likewise lives in earth, probably in crevices of rocks. In English
hothouses it is grown in peaty soil. Lady Dorothy Nevill was so kind as
to give me a fine plant, and I received another from Dr. Hooker. The
leaves are entire, instead of being much divided, as in the foregoing
aquatic species. They are elongated, about 1 1/2 inch in breadth, and
furnished with a distinct footstalk. The plant produces numerous
colourless rhizomes, as thin as threads, which bear minute bladders,
and occasionally swell into tubers, as will [page 432] hereafter be
described. These rhizomes appear exactly like roots, but occasionally
throw up green shoots. They penetrate the earth sometimes to the depth
of more than 2 inches; but when the plant grows as an epiphyte, they
must creep amidst the mosses, roots, decayed bark, &c., with which the
trees of these countries are thickly covered.
As the bladders are attached to the rhizomes, they are necessarily
subterranean. They are produced in extraordinary numbers. One of my
plants, though young, must have borne several hundreds; for a single
branch out of an entangled mass had thirty-two, and another branch,
about 2 inches in length (but with its end and one side branch broken
off), had seventy- three bladders.* The bladders are compressed and
rounded, with the ventral surface, or that between the summit of the
long delicate footstalk and valve, extremely short (fig. 27). They are
colourless and almost as transparent as glass, so that they appear
smaller than they really are, the largest being under the 1/20 of an
inch (1.27 mm.) in its longer diameter. They are formed of rather large
angular cells, at the junctions of which oblong papillae project,
corresponding with those on the surfaces of the bladders of the
previous species. Similar papillae abound on the rhizomes, and even on
the entire leaves, but they are rather broader on the latter. Vessels,
marked with parallel bars instead of by a spiral line, run up the
footstalks, and
* Prof. Oliver has figured a plant of Utricularia Jamesoniana (‘Proc.
Linn. Soc.’ vol. iv. p. 169) having entire leaves and rhizomes, like
those of our present species; but the margins of the terminal halves of
some of the leaves are converted into bladders. This fact clearly
indicates that the bladders on the rhizomes of the present and
following species are modified segments of the leaf; and they are thus
brought into accordance with the bladders attached to the divided and
floating leaves of the aquatic species. [page 433]
just enter the bases of the bladders; but they do not bifurcate and
extend up the dorsal and ventral surfaces, as in the previous species.
The antennæ are of moderate length, and taper to a fine point; they
differ conspicuously from those before described, in not being armed
with bristles. Their bases are so abruptly curved that their tips
generally rest one on each side of the middle of the bladder, but
FIG. 27. (Utricularia montana.) Bladder; about 27 times enlarged.
sometimes near the margin. Their curved bases thus form a roof over the
cavity in which the valve lies; but there is always left on each side a
little circular passage into the cavity, as may be seen in the drawing,
as well as a narrow passage between the bases of the two antennæ. As
the bladders are subterranean, had it not been for the roof, the cavity
in which the valve lies would have been liable to be blocked up with
earth [page 434] and rubbish; so that the curvature of the antennæ is a
serviceable character. There are no bristles on the outside of the
collar or peristome, as in the foregoing species.
The valve is small and steeply inclined, with its free posterior edge
abutting against a semicircular, deeply depending collar. It is
moderately transparent, and bears two pairs of short stiff bristles, in
the same position as in the other species. The presence of these four
bristles, in contrast with the absence of those on the antennæ and
collar, indicates that they are of functional importance, namely, as I
believe, to prevent too large animals forcing an entrance through the
valve. The many glands of diverse shapes attached to the valve and
round the collar in the previous species are here absent, with the
exception of about a dozen of the two-armed or transversely elongated
kind, which are seated near the borders of the valve, and are mounted
on very short footstalks. These glands are only the 3/4000 of an inch
(.019 mm.) in length; though so small, they act as absorbents. The
collar is thick, stiff, and almost semi-circular; it is formed of the
same peculiar brownish tissue as in the former species.
The bladders are filled with water, and sometimes include bubbles of
air. They bear internally rather short, thick, quadrifid processes
arranged in approximately concentric rows. The two pairs of arms of
which they are formed differ only a little in length, and stand in a
peculiar position (fig. 28); the two longer ones forming one line, and
the two shorter ones another parallel line. Each arm includes a small
spherical mass of brownish matter, which, when crushed, breaks into
angular pieces. I have no doubt that these spheres are nuclei, for
closely similar ones [page 435] are present in the cells forming the
walls of the bladders. Bifid processes, having rather short oval arms,
arise in the usual position on the inner side of the collar.
These bladders, therefore, resemble in all essential respects the
larger ones of the foregoing species. They differ chiefly in the
absence of the numerous glands on the valve and round the collar, a few
minute ones of one kind alone being present on the valve. They differ
more conspicuously in the absence of the long bristles on the antennæ
and on the outside of the collar. The presence of these bristles in the
previously mentioned species probably relates to the capture of aquatic
animals.
FIG. 28. (Utricularia montana.) One of the quadrifid processes; much
enlarged.
It seemed to me an interesting question whether the minute bladders of
Utricularia montanaserved, as in the previous species, to capture
animals living in the earth, or in the dense vegetation covering the
trees on which this species is epiphytic; for in this case we should
have a new sub-class of carnivorous plants, namely, subterranean
feeders. Many bladders, therefore, were examined, with the following
results:—
[(1) A small bladder, less than 1/30 of an inch (.847 mm.) in diameter,
contained a minute mass of brown, much decayed matter; and in this, a
tarsus with four or five joints, terminating in a double hook, was
clearly distinguished under the microscope. I suspect that it was a
remnant of one of the Thysanoura. The quadrifids in contact with this
decayed remnant contained either small masses of translucent, yellowish
matter, generally more [page 436] or less globular, or fine granules.
In distant parts of the same bladder, the processes were transparent
and quite empty, with the exception of their solid nuclei. My son made
at short intervals of time sketches of one of the above aggregated
masses, and found that they continually and completely changed their
forms; sometimes separating from one another and again coalescing.
Evidently protoplasm had been generated by the absorption of some
element from the decaying animal matter.
(2) Another bladder included a still smaller speck of decayed brown
matter, and the adjoining quadrifids contained aggregated matter,
exactly as in the last case.
(3) A third bladder included a larger organism, which was so much
decayed that I could only make out that it was spinose or hairy. The
quadrifids in this case were not much affected, excepting that the
nuclei in the several arms differed much in size; some of them
containing two masses having a similar appearance.
(4) A fourth bladder contained an articulate organism, for I distinctly
saw the remnant of a limb, terminating in a hook. The quadrifids were
not examined.
(5) A fifth included much decayed matter apparently of some animal, but
with no recognisable features. The quadrifids in contact contained
numerous spheres of protoplasm.
(6) Some few bladders on the plant which I received from Kew were
examined; and in one, there was a worm-shaped animal very little
decayed, with a distinct remnant of a similar one greatly decayed.
Several of the arms of the processes in contact with these remains
contained two spherical masses, like the single solid nucleus which is
properly found in each arm. In another bladder there was a minute grain
of quartz, reminding me of two similar cases with Utricularia neglecta.
As it appeared probable that this plant would capture a greater number
of animals in its native country than under culture, I obtained
permission to remove small portions of the rhizomes from dried
specimens in the herbarium at Kew. I did not at first find out that it
was advisable to soak the rhizomes for two or three days, and that it
was necessary to open the bladders and spread out their contents on
glass; as from their state of decay and from having been dried and
pressed, their nature could not otherwise be well distinguished.
Several bladders on a plant which had grown in black earth in New
Granada were first examined; and four of these included remnants of
animals. The first contained a hairy Acarus, so much decayed that
nothing was left except its transparent coat; [page 437] also a yellow
chitinous head of some animal with an internal fork, to which the
oesophagus was suspended, but I could see no mandibles; also the double
hook of the tarsus of some animal; also an elongated greatly decayed
animal; and lastly, a curious flask-shaped organism, having the walls
formed of rounded cells. Professor Claus has looked at this latter
organism, and thinks that it is the shell of a rhizopod, probably one
of the Arcellidae. In this bladder, as well as in several others, there
were some unicellular Algae, and one multicellular Alga, which no doubt
had lived as intruders.
A second bladder contained an Acarus much less decayed than the former
one, with its eight legs preserved; as well as remnants of several
other articulate animals. A third bladder contained the end of the
abdomen with the two hinder limbs of an Acarus, as I believe. A fourth
contained remnants of a distinctly articulated bristly animal, and of
several other organisms, as well as much dark brown organic matter, the
nature of which could not be made out.
Some bladders from a plant, which had lived as an epiphyte in Trinidad,
in the West Indies, were next examined, but not so carefully as the
others; nor had they been soaked long enough. Four of them contained
much brown, translucent, granular matter, apparently organic, but with
no distinguishable parts. The quadrifids in two were brownish, with
their contents granular; and it was evident that they had absorbed
matter. In a fifth bladder there was a flask-shaped organism, like that
above mentioned. A sixth contained a very long, much decayed,
worm-shaped animal. Lastly, a seventh bladder contained an organism,
but of what nature could not be distinguished.]
Only one experiment was tried on the quadrifid processes and glands
with reference to their power of absorption. A bladder was punctured
and left for 24 hrs. in a solution of one part of urea to 437 of water,
and the quadrifid and bifid processes were found much affected. In some
arms there was only a single symmetrical globular mass, larger than the
proper nucleus, and consisting of yellowish matter, generally
translucent but sometimes granular; in others there were two masses of
different sizes, one large and the [page 438] other small; and in
others there were irregularly shaped globules; so that it appeared as
if the limpid contents of the processes, owing to the absorption of
matter from the solution, had become aggregated sometimes round the
nucleus, and sometimes into separate masses; and that these then tended
to coalesce. The primordial utricle or protoplasm lining the processes
was also thickened here and there into irregular and variously shaped
specks of yellowish translucent matter, as occurred in the case of
Utricularia neglecta under similar treatment. These specks apparently
did not change their forms.
The minute two-armed glands on the valve were also affected by the
solution; for they now contained several, sometimes as many as six or
eight, almost spherical masses of translucent matter, tinged with
yellow, which slowly changed their forms and positions. Such masses
were never observed in these glands in their ordinary state. We may
therefore infer that they serve for absorption. Whenever a little water
is expelled from a bladder containing animal remains (by the means
formerly specified, more especially by the generation of bubbles of
air), it will fill the cavity in which the valve lies; and thus the
glands will be able to utilise decayed matter which otherwise would
have been wasted.
Finally, as numerous minute animals are captured by this plant in its
native country and when cultivated, there can be no doubt that the
bladders, though so small, are far from being in a rudimentary
condition; on the contrary, they are highly efficient traps. Nor can
there be any doubt that matter is absorbed from the decayed prey by the
quadrifid and bifid processes, and that protoplasm is thus generated.
What tempts animals of such diverse kinds to enter [page 439] the
cavity beneath the bowed antennæ, and then force their way through the
little slit-like orifice between the valve and collar into the bladders
filled with water, I cannot conjecture.
Tubers.—These organs, one of which is represented in a previous figure
(fig. 26) of the natural size, deserve a few remarks. Twenty were found
on the rhizomes of a single plant, but they cannot be strictly counted;
for, besides the twenty, there were all possible gradations between a
short length of a rhizome just perceptibly swollen and one so much
swollen that it might be doubtfully called a tuber. When well
developed, they are oval and symmetrical, more so than appears in the
figure. The largest which I saw was 1 inch (25.4 mm.) in length and .45
inch (11.43 mm.) in breadth. They commonly lie near the surface, but
some are buried at the depth of 2 inches. The buried ones are dirty
white, but those partly exposed to the light become greenish from the
development, of chlorophyll in their superficial cells. They terminate
in a rhizome, but this sometimes decays and drops off . They do not
contain any air, and they sink in water; their surfaces are covered
with the usual papillae. The bundle of vessels which runs up each
rhizome, as soon as it enters the tuber, separates into three distinct
bundles, which reunite at the opposite end. A rather thick slice of a
tuber is almost as translucent as glass, and is seen to consist of
large angular cells, full of water and not containing starch or any
other solid matter. Some slices were left in alcohol for several days,
but only a few extremely minute granules of matter were precipitated on
the walls of the cells; and these were much smaller and fewer than
those precipitated on the cell-walls of the rhizomes and bladders. We
may therefore con- [page 440] clude that the tuber do not serve as
reservoirs for food, but for water during the dry season to which the
plant is probably exposed. The many little bladders filled with water
would aid towards the same end.
To test the correctness of this view, a small plant, growing in light
peaty earth in a pot (only 4 1/2 by 4 1/2 inches outside measure) was
copiously watered, and then kept without a drop of water in the
hothouse. Two of the upper tubers were beforehand uncovered and
measured, and then loosely covered up again. In a fortnight’s time the
earth in the pot appeared extremely dry; but not until the thirty-fifth
day were the leaves in the least affected; they then became slightly
reflexed, though still soft and green. This plant, which bore only ten
tubers, would no doubt have resisted the drought for even a longer
time, had I not previously removed three of the tubers and cut off
several long rhizomes. When, on the thirty-fifth day, the earth in the
pot was turned out, it appeared as dry as the dust on a road. All the
tubers had their surfaces much wrinkled, instead of being smooth and
tense. They had all shrunk, but I cannot say accurately how much; for
as they were at first symmetrically oval, I measured only their length
and thickness; but they contracted in a transverse line much more in
one direction than in another, so as to become greatly flattened. One
of the two tubers which had been measured was now three-fourths of its
original length, and two-thirds of its original thickness in the
direction in which it had been measured, but in another direction only
one- third of its former thickness. The other tuber was one-fourth
shorter, one-eighth less thick in the direction in which it had been
measured, and only half as thick in another direction.
A slice was cut from one of these shrivelled tubers [page 441] and
examined. The cells still contained much water and no air, but they
were more rounded or less angular than before, and their walls not
nearly so straight; it was therefore clear that the cells had
contracted. The tubers, as long as they remain alive, have a strong
attraction for water; the shrivelled one, from which a slice had been
cut, was left in water for 22 hrs. 30 m., and its surface became as
smooth and tense as it originally was. On the other hand, a shrivelled
tuber, which by some accident had been separated from its rhizome, and
which appeared dead, did not swell in the least, though left for
several days in water.
With many kinds of plants, tubers, bulbs, &c. no doubt serve in part as
reservoirs for water, but I know of no case, besides the present one,
of such organs having been developed solely for this purpose. Prof.
Oliver informs me that two or three species of Utricularia are provided
with these appendages; and the group containing them has in consequence
received the name of orchidioides. All the other species of
Utricularia, as well as of certain closely related genera, are either
aquatic or marsh plants; therefore, on the principle of nearly allied
plants generally having a similar constitution, a never failing supply
of water would probably be of great importance to our present species.
We can thus understand the meaning of the development of its tubers,
and of their number on the same plant, amounting in one instance to at
least twenty.
UTRICULARIA NELUMBIFOLIA, AMETHYSTINA, GRIFFITHII, CAERULEA,
ORBICULATA, MULTICAULIS.
As I wished to ascertain whether the bladders on the rhizomes of other
species of Utricularia, and of the [page 442] species of certain
closely allied genera, had the same essential structure as those of
Utricularia montana, and whether they captured prey, I asked Prof.
Oliver to send me fragments from the herbarium at Kew. He kindly
selected some of the most distinct forms, having entire leaves, and
believed to inhabit marshy ground or water. My son Francis Darwin,
examined them, and has given me the following observations; but it
should be borne in mind that it is extremely difficult to make out the
structure of such minute and delicate objects after they have been
dried and pressed.*
Utricularia nelumbifolia (Organ Mountains, Brazil).—The habitat of this
species is remarkable. According to its discoverer, Mr. Gardner,** it
is aquatic, but “is only to be found growing in the water which
collects in the bottom of the leaves of a large Tillandsia, that
inhabits abundantly an arid rocky part of the mountain, at an elevation
of about 5000 feet above the level of the sea. Besides the ordinary
method by seed, it propagates itself by runners, which it throws out
from the base of the flower-stem; this runner is always found directing
itself towards the nearest Tillandsia, when it inserts its point into
the water and gives origin to a new plant, which in its turn sends out
another shoot. In this manner I have seen not less than six plants
united.” The bladders resemble those of Utricularia montana in all
essential respects, even to the presence of a few minute two-armed
glands on the valve. Within one bladder there was the remnant of the
abdomen of some larva or crustacean of large size,
* Prof. Oliver has given (‘Proc. Linn. Soc.’ vol. iv. p. 169) figures
of the bladders of two South American species, namely Utricularia
Jamesoniana and peltata; but he does not appear to have paid particular
attention to these organs.
** ‘Travels in the Interior of Brazil, 1836-41,’ p. 527. [page 443]
having a brush of long sharp bristles at the apex. Other bladders
included fragments of articulate animals, and many of them contained
broken pieces of a curious organism, the nature of which was not
recognised by anyone to whom it was shown.
Utricularia amethystina (Guiana).—This species has small entire leaves,
and is apparently a marsh plant; but it must grow in places where
crustaceans exist, for there were two small species within one of the
bladders. The bladders are nearly of the same shape as those of
Utricularia montana, and are covered outside with the usual papillae;
but they differ remarkably in the antennæ being reduced to two short
points, united by a membrane hollowed out in the middle. This membrane
is covered with innumerable oblong glands supported on long footstalks;
most of which are arranged in two rows converging towards the valve.
Some, however, are seated on the margins of the membrane; and the short
ventral surface of the bladder, between the petiole and valve, is
thickly covered with glands. Most of the heads had fallen off, and the
footstalks alone remained; so that the ventral surface and the orifice,
when viewed under a weak power, appeared as if clothed with fine
bristles. The valve is narrow, and bears a few almost sessile glands.
The collar against which the edge shuts is yellowish, and presents the
usual structure. From the large number of glands on the ventral surface
and round the orifice, it is probable that this species lives in very
foul water, from which it absorbs matter, as well as from its captured
and decaying prey.
Utricularia griffithii (Malay and Borneo).—The bladders are transparent
and minute; one which was measured being only 28/1000 of an inch (.711
mm.) in diameter. The antennæ are of moderate length, and [page 444]
project straight forward; they are united for a short space at their
bases by a membrane; and they bear a moderate number of bristles or
hairs, not simple as heretofore, but surmounted by glands. The bladders
also differ remarkably from those of the previous species, as within
there are no quadrifid, only bifid, processes. In one bladder there was
a minute aquatic larva; in another the remains of some articulate
animal; and in most of them grains of sand.
Utricularia caerulea (India).—The bladders resemble those of the last
species, both in the general character of the antennæ and in the
processes within being exclusively bifid. They contained remnants of
entomostracan crustaceans.
Utricularia orbiculata (India).—The orbicular leaves and the stems
bearing the bladders apparently float in water. The bladders do not
differ much from those of the two last species. The antennæ, which are
united for a short distance at their bases, bear on their outer
surfaces and summits numerous, long, multicellular hairs, surmounted by
glands. The processes within the bladders are quadrifid, with the four
diverging arms of equal length. The prey which they had captured
consisted of entomostracan crustaceans.
Utricularia multicaulis (Sikkim, India, 7000 to 11,000 feet).—The
bladders, attached to rhizomes, are remarkable from the structure of
the antennæ. These are broad, flattened, and of large size; they bear
on their margins multicellular hairs, surmounted by glands. Their bases
are united into a single, rather narrow pedicel, and they thus appear
like a great digitate expansion at one end of the bladder. Internally
the quadrifid processes have divergent arms of equal length. The
bladders contained remnants of articulate animals. [page 445]
POLYPOMPHOLYX.
This genus, which is confined to Western Australia, is characterised by
having a “quadripartite calyx.” In other respects, as Prof. Oliver
remarks,* “it is quite a Utricularia.”
Polypompholyx multifida.—The bladders are attached in whorls round the
summits of stiff stalks. The two antennæ are represented by a minute
membranous fork, the basal part of which forms a sort of hood over the
orifice. This hood expands into two wings on each side of the bladder.
A third wing or crest appears to be formed by the extension of the
dorsal surface of the petiole; but the structure of these three wings
could not be clearly made out, owing to the state of the specimens. The
inner surface of the hood is lined with long simple hairs, containing
aggregated matter, like that within the quadrifid processes of the
previously described species when in contact with decayed animals.
These hairs appear therefore to serve as absorbents. A valve was seen,
but its structure could not be determined. On the collar round the
valve there are in the place of glands numerous one-celled papillae,
having very short footstalks. The quadrifid processes have divergent
arms of equal length. Remains of entomostracan crustaceans were found
within the bladders.
Polypompholyx tenella.—The bladders are smaller than those of the last
species, but have the same general structure. They were full of dbris,
apparently organic, but no remains of articulate animals could be
distinguished.
* ‘Proc. Linn. Soc.’ vol. iv. p. 171. [page 446]
GENLISEA.
This remarkable genus is technically distinguished from Utricularia, as
I hear from Prof. Oliver, by having a five-partite calyx. Species are
found in several parts of the world, and are said to be “herbae annuae
paludosae.”
Genlisea ornata (Brazil).—This species has been described and figured
by Dr. Warming,* who states that it bears two kinds of leaves, called
by him spathulate and utriculiferous. The latter include cavities; and
as these differ much from the bladders of the foregoing species, it
will be convenient to speak of them as utricles. The accompanying
figure (fig. 29) of one of the utriculiferous leaves, about thrice
enlarged, will illustrate the following description by my son, which
agrees in all essential points with that given by Dr. Warming. The
utricle (b) is formed by a slight enlargement of the narrow blade of
the leaf. A hollow neck (n), no less than fifteen times as long as the
utricle itself, forms a passage from the transverse slit-like orifice
(o) into the cavity of the utricle. A utricle which measured 1/36 of an
inch (.705 mm.,) in its longer diameter had a neck 15/36 (10.583 mm.)
in length, and 1/100 of an inch (.254 mm.) in breadth. On each side of
the orifice there is a long spiral arm or tube (a); the structure of
which will be best understood by the following illustration. Take a
narrow ribbon and wind it spirally round a thin cylinder, so that the
edges come into contact along its whole length; then pinch up the two
edges so as to form a little crest, which will of course wind spirally
* “Bidrag til Kundskaben om Lentibulariaceae,” Copenhagen 1874. [page
447]
round the cylinder like a thread round a screw. If the cylinder is now
removed, we shall have a tube like one of the spiral arms. The two
projecting edges are not actually united, and a needle can be pushed in
easily between them. They are indeed in many places a little separated,
forming narrow entrances into the tube; but this may be the result of
the drying of the specimens. The lamina of which the tube is formed
seems to be a lateral prolongation of the lip of the orifice; and the
spiral line between the two projecting edges is continuous with the
corner of the orifice. If a fine bristle is pushed down one of the
arms, it passes into the top of the hollow neck. Whether the arms are
open or closed at their extremities could not be determined, as all the
specimens were broken; nor does it appear that Dr. Warming ascertained
this point.
FIG. 29. (Genlisea ornata.) Utriculiferous leaf; enlarged about three
times. l Upper part of lamina of leaf. b Utricle or bladder. n Neck of
utricle. o Orifice. a Spirally wound arms, with their ends broken off.
So much for the external structure. Internally the lower part of the
utricle is covered with spherical papillae, formed of four cells
(sometimes eight according to Dr. Warming), which evidently answer to
the quadrifid processes within the bladders of Utricularia. [page 448]
These papillae extend a little way up the dorsal and ventral surfaces
of the utricle; and a few, according to Warming, may be found in the
upper part. This upper region is covered by many transverse rows, one
above the other, of short, closely approximate hairs, pointing
downwards. These hairs have broad bases, and their tips are formed by a
separate cell. They are absent in the lower part of the utricle where
the papillae abound.
FIG. 30. (Genlisea ornata.) Portion of inside of neck leading into the
utricle, greatly enlarged, showing the downward pointed bristles, and
small quadrifid cells or processes.
The neck is likewise lined throughout its whole length with transverse
rows of long, thin, transparent hairs, having broad bulbous (fig. 30)
bases, with similarly constructed sharp points. They arise from little
projecting ridges, formed of rectangular epidermic cells. The hairs
vary a little in length, but their points generally extend down to the
row next below; so that if the neck is split open and laid flat, the
inner surface resembles a paper of pins,—the hairs representing the
pins, and the little transverse ridges representing the folds of paper
through which the pins are thrust. These rows of hairs are indicated in
the previous figure (29) by numerous transverse lines crossing the
neck. The inside of the neck is [page 449] also studded with papillae;
those in the lower part are spherical and formed of four cells, as in
the lower part of the utricle; those in the upper part are formed of
two cells, which are much elongated downwards beneath their points of
attachment. These two-celled papillae apparently correspond with the
bifid process in the upper part of the bladders of Utricularia. The
narrow transverse orifice (o, fig. 29) is situated between the bases of
the two spiral arms. No valve could be detected here, nor was any such
structure seen by Dr. Warming. The lips of the orifice are armed with
many short, thick, sharply pointed, somewhat incurved hairs or teeth.
The two projecting edges of the spirally wound lamina, forming the
arms, are provided with short incurved hairs or teeth, exactly like
those on the lips. These project inwards at right angles to the spiral
line of junction between the two edges. The inner surface of the lamina
supports two-celled, elongated papillae, resembling those in the upper
part of the neck, but differing slightly from them, according to
Warming, in their footstalks being formed by prolongations of large
epidermic cells; whereas the papillae within the neck rest on small
cells sunk amidst the larger ones. These spiral arms form a conspicuous
difference between the present genus and Utricularia.
Lastly, there is a bundle of spiral vessels which, running up the lower
part of the linear leaf, divides close beneath the utricle. One branch
extends up the dorsal and the other up the ventral side of both the
utricle and neck. Of these two branches, one enters one spiral arm, and
the other branch the other arm.
The utricles contained much dbris or dirty matter, which seemed
organic, though no distinct organisms [page 450] could be recognised.
It is, indeed, scarcely possible that any object could enter the small
orifice and pass down the long narrow neck, except a living creature.
Within the necks, however, of some specimens, a worm with retracted
horny jaws, the abdomen of some articulate animal, and specks of dirt,
probably the remnants of other minute creatures, were found. Many of
the papillae within both the utricles and necks were discoloured, as if
they had absorbed matter.
From this description it is sufficiently obvious how Genlisea secures
its prey. Small animals entering the narrow orifice—but what induces
them to enter is not known any more than in the case of
Utricularia—would find their egress rendered difficult by the sharp
incurved hairs on the lips, and as soon as they passed some way down
the neck, it would be scarcely possible for them to return, owing to
the many transverse rows of long, straight, downward pointing hairs,
together with the ridges from which these project. Such creatures
would, therefore, perish either within the neck or utricle; and the
quadrifid and bifid papillae would absorb matter from their decayed
remains. The transverse rows of hairs are so numerous that they seem
superfluous merely for the sake of preventing the escape of prey, and
as they are thin and delicate, they probably serve as additional
absorbents, in the same manner as the flexible bristles on the infolded
margins of the leaves of Aldrovanda. The spiral arms no doubt act as
accessory traps. Until fresh leaves are examined, it cannot be told
whether the line of junction of the spirally wound lamina is a little
open along its whole course, or only in parts, but a small creature
which forced its way into the tube at any point, would be prevented
from escaping by the incurved hairs, and would find an open path down
[page 451] the tube into the neck, and so into the utricle. If the
creature perished within the spiral arms, its decaying remains would be
absorbed and utilised by the bifid papillae. We thus see that animals
are captured by Genlisea, not by means of an elastic valve, as with the
foregoing species, but by a contrivance resembling an eel-trap, though
more complex.
Genlisea africana (South Africa).—Fragments of the utriculiferous
leaves of this species exhibited the same structure as those of
Genlisea ornata. A nearly perfect Acarus was found within the utricle
or neck of one leaf, but in which of the two was not recorded.
Genlisea aurea (Brazil).—A fragment of the neck of a utricle was lined
with transverse rows of hairs, and was furnished with elongated
papillae, exactly like those within the neck of Genlisea ornata. It is
probable, therefore, that the whole utricle is similarly constructed.
Genlisea filiformis (Bahia, Brazil).—Many leaves were examined and none
were found provided with utricles, whereas such leaves were found
without difficulty in the three previous species. On the other hand,
the rhizomes bear bladders resembling in essential character those on
the rhizomes of Utricularia. These bladders are transparent, and very
small, viz. Only 1/100 of an inch (.254 mm.) in length. The antennæ are
not united at their bases, and apparently bear some long hairs. On the
outside of the bladders there are only a few papillae, and internally
very few quadrifid processes. These latter, however, are of unusually
large size, relatively to the bladder, with the four divergent arms of
equal length. No prey could be seen within these minute bladders. As
the rhizomes of this species were furnished with bladders, those of
Genlisea africana, ornata, and aurea were carefully [page 452]
examined, but none could be found. What are we to infer from these
facts? Did the three species just named, like their close allies, the
several species of Utricularia, aboriginally possess bladders on their
rhizomes, which they afterwards lost, acquiring in their place
utriculiferous leaves? In support of this view it may be urged that the
bladders of Genlisea filiformis appear from their small size and from
the fewness of their quadrifid processes to be tending towards
abortion; but why has not this species acquired utriculiferous leaves,
like its congeners?
CONCLUSION.
It has now been shown that many species of Utricularia and of two
closely allied genera, inhabiting the most distant parts of the
world—Europe, Africa, India, the Malay Archipelago, Australia, North
and South America—are admirably adapted for capturing by two methods
small aquatic or terrestrial animals, and that they absorb the products
of their decay.
Ordinary plants of the higher classes procure the requisite inorganic
elements from the soil by means of their roots, and absorb carbonic
acid from the atmosphere by means of their leaves and stems. But we
have seen in a previous part of this work that there is a class of
plants which digest and afterwards absorb animal matter, namely, all
the Droseraceae, Pinguicula, and, as discovered by Dr. Hooker,
Nepenthes, and to this class other species will almost certainly soon
be added. These plants can dissolve matter out of certain vegetable
substances, such as pollen, seeds, and bits of leaves. No doubt their
glands likewise absorb the salts of ammonia brought to them by the
rain. It has also been shown that some other plants can absorb ammonia
by [page 453] their glandular hairs; and these will profit by that
brought to them by the rain. There is a second class of plants which,
as we have just seen, cannot digest, but absorb the products of the
decay of the animals which they capture, namely, Utricularia and its
close allies; and from the excellent observations of Dr. Mellichamp and
Dr. Canby, there can scarcely be a doubt that Sarracenia and
Darlingtonia may be added to this class, though the fact can hardly be
considered as yet fully proved. There is a third class of plants which
feed, as is now generally admitted, on the products of the decay of
vegetable matter, such as the bird’s-nest orchis (Neottia), &c. Lastly,
there is the well-known fourth class of parasites (such as the
mistletoe), which are nourished by the juices of living plants. Most,
however, of the plants belonging to these four classes obtain part of
their carbon, like ordinary species, from the atmosphere. Such are the
diversified means, as far as at present known, by which higher plants
gain their subsistence.
INDEX.
A.
Absorption by Dionaea, 295
— by Drosera, 17
— by Drosophyllum, 337
— by Pinguicula, 381
— by glandular hairs, 344
— by glands of Utricularia, 416, 421
— by quadrifids of Utricularia, 413, 421
— by Utricularia montana, 437
Acid, nature of, in digestive secretion of Drosera, 88 — present in
digestive fluid of various species of Drosera, Dionaea, Drosophyllum,
and Pinguicula, 278, 301, 339, 381
Acids, various, action of, on Drosera, 188 — of the acetic series
replacing hydrochloric in digestion, 89 —, arsenious and chromic,
action on Drosera, 185 —, diluted, inducing negative osmose, 197
Adder’s poison, action on Drosera, 206
Aggregation of protoplasm in Drosera, 38 — in Drosera induced by salts
of ammonia, 43 — — caused by small doses of carbonate of ammonia, 145 —
of protoplasm in Drosera, a reflex action, 242 — — in various species
of Drosera, 278 — — in Dionaea, 290, 300
Aggregation of protoplasm in Drosophyllum, 337, 339 — — in Pinguicula,
370, 389 — — in Utricularia, 411, 415, 429, 430, 436
Albumen, digested by Drosera, 92 —, liquid, action on Drosera, 79
Alcohol, diluted, action of, on Drosera, 78, 216
Aldrovanda vesiculosa, 321 —, absorption and digestion by, 325 —,
varieties of, 329
Algae, aggregation in fronds of, 65
Alkalies, arrest digestive process in Drosera, 94
Aluminium, salts of, action on Drosera, 184
Ammonia, amount of, in rain water, 172 —, carbonate, action on heated
leaves of Drosera, 69 —, —, smallness of doses causing aggregation in
Drosera, 145 —, —, its action on Drosera, 141 —, —, vapour of, absorbed
by glands of Drosera, 142 —, —, smallness of doses causing inflection
in Drosera, 145, 168 —, phosphate, smallness of doses causing
inflection in Drosera, 153, 168 —, —, size of particles affecting
Drosera, 173 —, nitrate, smallness of doses causing inflection in
Drosera, 148, 168 —, salts of, action on Drosera, 136
Ammonia, salts of, their action affected by previous immersion in water
and various solutions, 213 —, —, induce aggregation in Drosera, 43 —,
various salts of, causing inflection in Drosera, 166
Antimony, tartrate, action on Drosera, 185
Areolar tissue, its digestion by Drosera, 102
Arsenious acid, action on Drosera, 185
Atropine, action on Drosera, 204
B.
Barium, salts of, action on Drosera, 183
Bases of salts, preponderant action of, on Drosera, 186
Basis, fibrous, of bone, its digestion by Drosera, 108
Belladonna, extract of, action on Drosera, 84
Bennett, Mr. A.W., on Drosera, 2 —, coats of pollen-grains not digested
by insects, 117
Binz, on action of quinine on white blood-corpuscles, 201 —, on
poisonous action of quinine on low organisms, 202
Bone, its digestion by Drosera, 105
Brunton, Lauder, on digestion of gelatine, 111 —, on the composition of
casein, 115 —, on the digestion of urea, 124 —, — of chlorophyll, 126
—, — of pepsin, 124
Byblis, 343
C.
Cabbage, decoction of, action on Drosera, 83
Cadmium chloride, action on Drosera, 183
Caesium, chloride of, action on Drosera, 181
Calcium, salts of, action on Drosera, 182
Camphor, action on Drosera, 209
Canby, Dr., on Dionaea, 301, 310, 313 —, on Drosera filiformis, 281
Caraway, oil of, action on Drosera, 211
Carbonic acid, action on Drosera, 221 —, delays aggregation in Drosera,
59
Cartilage, its digestion by Drosera, 103
Casein, its digestion by Drosera, 114
Cellulose, not digested by Drosera, 125
Chalk, precipitated, causing inflection of Drosera, 32
Cheese, its digestion by Drosera, 116
Chitine, not digested by Drosera, 124
Chloroform, effects of, on Drosera, 217 —, —, on Dionaea, 304
Chlorophyll, grains of, in living plants, digested by Drosera, 126 —,
pure, not digested by Drosera, 125
Chondrin, its digestion by Drosera, 112
Chromic acid, action on Drosera, 185
Cloves, oil of, action on Drosera, 212
Cobalt chloride, action on Drosera, 186
Cobra poison, action on Drosera, 206
Cohn, Prof., on Aldrovanda, 321 —, on contractile tissues in plants,
364 —, on movements of stamens of Compositae, 256 —, on Utricularia,
395
Colchicine, action on Drosera, 204
Copper chloride, action on Drosera, 185
Crystallin, its digestion by Drosera, 120
Curare, action on Drosera, 204
Curtis, Dr., on Dionaea, 301
D.
Darwin, Francis, on the effect of an induced galvanic current on
Drosera, 37 —, on the digestion of grains of chlorophyll, 126 —, on
Utricularia, 442
Delpino, on Aldrovanda, 321 —, on Utricularia, 395
Dentine, its digestion by Drosera, 106
Digestion of various substances by Dionaea, 301 — — by Drosera, 85 — —
by Drosophyllum, 339 — — by Pinguicula, 381 —, origin of power of, 361
Digitaline, action on Drosera, 203
Dionaea muscipula, small size of roots, 286 —, structure of leaves, 287
—, sensitiveness of filaments, 289 —, absorption by, 295 —, secretion
by, 295 —, digestion by, 301 —, effects on, of chloroform, 304 —,
manner of capturing insects, 305 —, transmission of motor impulse, 313
—, re-expansion of lobes, 318
Direction of inflected tentacles of Drosera, 243
Dohrn, Dr., on rhizocephalous crustaceans, 357
Donders, Prof., small amount of atropine affecting the iris of the dog,
172
Dragonfly caught by Drosera, 2
Drosera anglica, 278 — binata, vel dichotoma, 281 — capensis, 279 —
filiformis, 281 — heterophylla, 284 — intermedia, 279
Drosera rotundifolia, structure of leaves, 4 —, effects on, of
nitrogenous fluids, 76 Drosera rotundifolia, effects of heat on, 66 —,
its power of digestion, 85 —, backs of leaves not sensitive, 231 —,
transmission of motor impulse, 234 —, general summary, 262 —
spathulata, 280
Droseraceae, concluding remarks on, 355 —, their sensitiveness compared
with that of animals, 366
Drosophyllum, structure of leaves, 333 —, secretion by, 334 —,
absorption by, 337 —, digestion by, 339
E.
Enamel, its digestion by Drosera, 106
Erica tetralix, glandular hairs of, 351
Ether, effects of, on Drosera, 219 —, —, on Dionaea, 304
Euphorbia, process of aggregation in roots of, 63
Exosmose from backs of leaves of Drosera, 231
F.
Fat not digested by Drosera, 126
Fayrer, Dr., on the nature of cobra poison, 206 —, on the action of
cobra poison on animal protoplasm, 208 —, on cobra poison paralysing
nerve centres, 224
Ferment, nature of, in secretion of Drosera, 94, 97
Fibrin, its digestion by Drosera, 100
Fibro-cartilage, its digestion by Drosera, 104
Fibro-elastic tissue, not digested by Drosera, 122
Fibrous basis of bone, its digestion by Drosera, 108
Fluids, nitrogenous, effects of, on Drosera, 76
Fournier, on acids causing movements in stamens of Berberis, 196
Frankland, Prof., on nature of acid in secretion of Drosera, 88
G.
Galvanism, current of, causing inflection of Drosera, 37 —, effects of,
on Dionaea, 318
Gardner, Mr., on Utricularia nelumbifolia, 442
Gelatin, impure, action on Drosera, 80 —, pure, its digestion by
Drosera, 110
Genlisea africana, 451 — filiformis, 451
Genlisea ornata, structure of, 446 —, manner of capturing prey, 450
Glandular hairs, absorption by, 344 —, summary on, 353
Globulin, its digestion by Drosera, 120
Gluten, its digestion by Drosera, 117
Glycerine, inducing aggregation in Drosera, 52 —, action on Drosera,
212
Gold chloride, action on Drosera, 184
Gorup-Besanez on the presence of a solvent in seeds of the vetch, 362
Grass, decoction of, action on Drosera, 84
Gray, Asa, on the Droseraceae, 2
Groenland, on Drosera, 1, 5
Gum, action of, on Drosera, 77
Gun-cotton, not digested by Drosera, 125
H.
Haematin, its digestion by Drosera, 121
Hairs, glandular, absorption by, 344 —, —, summary on, 353
Heat, inducing aggregation in Drosera, 53 —, effect of, on Drosera, 66
—, —, on Dionaea, 294, 319
Heckel, on state of stamens of Berberis after excitement, 43
Hofmeister, on pressure arresting movements of protoplasm, 61
Holland, Mr., on Utricularia, 395
Hooker, Dr., on carnivorous plants, 2 —, on power of digestion by
Nepenthes, 97 —, history of observations on Dionaea, 286
Hydrocyanic acid, effects of, on Dionaea, 305
Hyoscyamus, action on Drosera, 84, 206
I.
Iron chloride, action on Drosera, 185
Isinglass, solution of, action on Drosera, 80
J.
Johnson, Dr., on movement of flower-stems of Pinguicula, 381
K.
Klein, Dr., on microscopic character of half digested bone, 106 —, on
state of half digested fibro-cartilage, 104 —, on size of micrococci,
173
Knight, Mr., on feeding Dionaea, 301
Kossmann, Dr., on rhizocephalous crustaceans, 357
L.
Lead chloride, action on Drosera, 184
Leaves of Drosera, backs of, not sensitive, 231
Legumin, its digestion by Drosera, 116
Lemna, aggregation in leaves of, 64
Lime, carbonate of, precipitated, causing inflection of Drosera, 32 —,
phosphate of, its action on Drosera, 109
Lithium, salts of, action on Drosera, 181
M.
Magnesium, salts of, action on Drosera, 182
Manganese chloride, action on Drosera, 185
Marshall, Mr. W., on Pinguicula, 369
Means of movement in Dionaea, 313 — in Drosera, 254
Meat, infusion of, causing aggregation in Drosera, 51 —, —, action on
Drosera, 79 —, its digestion by Drosera, 98
Mercury perchloride, action on Drosera, 183
Milk, inducing aggregation in Drosera, 51 —, action on Drosera, 79 —,
its digestion by Drosera, 113
Mirabilis longiflora, glandular hairs of, 352
Moggridge, Traherne, on acids injuring seeds, 128
Moore, Dr., on Pinguicula, 390
Morphia acetate, action on Drosera, 205
Motor impulse in Drosera, 234, 258 — in Dionaea, 313
Movement, origin of power of, 363
Movements of leaves of Pinguicula, 371 — of tentacles of Drosera, means
of, 254 — of Dionaea, means of, 313
Mucin, not digested by Drosera, 122
Mucus, action on Drosera, 80
Müller, Fritz, on rhizocephalous crustaceans, 357
N.
Nepenthes, its power of digestion, 97
Nickel chloride, action on Drosera, 186
Nicotiana tabacum, glandular hairs of, 352
Nicotine, action on Drosera, 203
Nitric ether, action on Drosera, 220
Nitschke, Dr., references to his papers on Drosera, 1 —, on
sensitiveness of backs of leaves of Drosera, 231 —, on direction of
inflected tentacles in Drosera, 244 —, on Aldrovanda, 322
Nourishment, various means of, by plants, 452
Nuttall, Dr., on re-expansion of Dionaea, 318
O.
Odour of pepsin, emitted from leaves of Drosera, 88
Oil, olive, action of, on Drosera, 78, 126
Oliver, Prof., on Utricularia, 432, 441-446
P.
Papaw, juice of, hastening putrefaction, 411
Particles, minute size of, causing inflection in Drosera, 27, 32
Peas, decoction of, action on Drosera, 82
Pelargonium zonale, glandular hairs of, 350
Pepsin, odour of, emitted from Drosera leaves, 88 —, not digested by
Drosera, 123 —, its secretion by animals excited only after absorption,
129
Peptogenes, 129
Pinguicula grandiflora, 390 — lusitanica, 391
Pinguicula vulgaris, structure of leaves and roots, 368 —, number of
insects caught by, 369 —, power of movement, 371 —, secretion and
absorption by, 381 —, digestion by, 381 —, effects of secretion on
living seeds, 390
Platinum chloride, action on Drosera, 186
Poison of cobra and adder, their action on Drosera, 206
Pollen, its digestion by Drosera, 117
Polypompholyx, structure of, 445
Potassium, salts of, inducing aggregation in Drosera, 50 —, —, action
on Drosera, 179 — phosphate, not decomposed by Drosera, 180, 187
Price, Mr. John, on Utricularia, 429
Primula sinensis, glandular hairs of, 348 —, number of glandular hairs
of, 355
Protoplasm, aggregation of, in Drosera, 38 —, —, in Drosera, caused by
small doses of carbonate of ammonia, 145 —, —, in Drosera, a reflex
action, 242 — aggregated, re-dissolution of, 53 —, aggregation of, in
various species of Drosera, 278 —, —, in Dionaea, 290, 300 —, —, in
Drosophyllum, 337, 339 —, —, in Pinguicula, 370, 389 —, —, in
Utricularia, 411, 415, 429, 430, 436
Q.
Quinine, salts of, action on Drosera, 201
R.
Rain-water, amount of ammonia in, 172
Ralfs, Mr., on Pinguicula, 390
Ransom, Dr., action of poisons on the yolk of eggs, 225
Re-expansion of headless tentacles of Drosera, 229 — of tentacles of
Drosera, 260 — of Dionaea, 318
Roots of Drosera, 18 — of Drosera, process of aggregation in, 63 — of
Drosera, absorb carbonate of ammonia, 141 — of Dionaea, 286 — of
Drosophyllum, 332 — of Pinguicula, 369
Roridula, 342
Rubidium chloride, action on Drosera, 181
S.
Sachs, Prof., effects of heat on protoplasm, 66, 70 —, on the
dissolution of proteid compounds in the tissues of plants, 362
Saliva, action on Drosera, 80
Salts and acids, various, effects of, on subsequent action of ammonia,
214
Sanderson, Burdon, on coagulation of albumen from heat, 74 —, on acids
replacing hydrochloric in digestion, 89 —, on the digestion of fibrous
basis of bone, 108 —, — of gluten, 118 —, — of globulin, 120 —, — of
chlorophyll, 126 —, on different effect of sodium and potassium on
animals, 187 —, on electric currents in Dionaea, 318
Saxifraga umbrosa, glandular hairs of, 345
Schiff, on hydrochloric acid dissolving coagulated albumen, 86 —, on
manner of digestion of albumen, 93 —, on changes in meat during
digestion, 99 —, on the coagulation of milk, 114 —, on the digestion of
casein, 116 —, — of mucus, 123 —, on peptogenes, 129
Schloesing, on absorption of nitrogen by Nicotiana, 352
Scott, Mr., on Drosera, 1
Secretion of Drosera, general account of, 13 — —, its antiseptic power,
15 — —, becomes acid from excitement, 86 — —, nature of its ferment,
94, 97 — by Dionaea, 295 — by Drosophyllum, 335 — by Pinguicula, 381
Seeds, living, acted on by Drosera, 127 —, —, acted on by Pinguicula,
385, 390
Sensitiveness, localisation of, in Drosera, 229 — of Dionaea, 289 — of
Pinguicula, 371
Silver nitrate, action on Drosera, 181
Sodium, salts of, action on Drosera, 176 —, —, inducing aggregation in
Drosera, 50
Sondera heterophylla, 284
Sorby, Mr., on colouring matter of Drosera, 5
Spectroscope, its power compared with that of Drosera, 170
Starch, action of, on Drosera, 78, 126
Stein, on Aldrovanda, 321
Strontium, salts of, action on Drosera, 183
Strychnine, salts of, action on Drosera, 199
Sugar, solution of, action of, on Drosera, 78 —, —, inducing
aggregation in Drosera, 51
Sulphuric ether, action on Drosera, 219 —, — on Dionaea, 304
Syntonin, its action on Drosera, 102
T.
Tait, Mr., on Drosophyllum, 332
Taylor, Alfred, on the detection of minute doses of poisons, 170
Tea, infusion of, action on Drosera, 78
Tentacles of Drosera, move when glands cut of, 36, 229 —, inflection,
direction of, 243 —, means of movement, 254 —, re-expansion of, 260
Theine, action on Drosera, 204
Tin chloride, action on Drosera, 185
Tissue, areolar, its digestion by Drosera, 102 —, fibro-elastic, not
digested by Drosera, 122
Tissues through which impulse is transmitted in Drosera, 247 — — in
Dionaea, 313
Touches repeated, causing inflection in Drosera, 34
Transmission of motor impulse in Drosera, 234 — — in Dionaea, 313
Traube, Dr., on artificial cells, 216
Treat, Mrs., on Drosera filiformis, 281 —, on Dionaea, 311 —, on
Utricularia, 408, 430
Trcul, on Drosera, 1, 5
Tubers of Utricularia montana, 439
Turpentine, action on Drosera, 212
U.
Urea, not digested by Drosera, 124
Urine, action on Drosera, 79
Utricularia clandestina, 430 — minor, 429
Utricularia montana, structure of bladders, 431 —, animals caught by,
435 —, absorption by, 437 —, tubers of, serving as reservoirs, 439
Utricularia neglecta, structure of bladders, 397 —, animals caught by,
405 —, absorption by, 413 —, summary on absorption, 421 —, development
of bladders, 424
Utricularia, various species of, 441
Utricularia vulgaris, 428
V.
Veratrine, action on Drosera, 204
Vessels in leaves of Drosera, 247 — of Dionaea, 314
Vogel, on effects of camphor on plants, 209
W.
Warming, Dr., on Drosera, 2, 6 —, on roots of Utricularia, 397 —, on
trichomes, 359 —, on Genlisea, 446 —, on parenchymatous cells in
tentacles of Drosera, 252
Water, drops of, not causing inflection in Drosera, 35 —, its power in
causing aggregation in Drosera, 52 —, its power in causing inflection
in Drosera, 139 — and various solutions, effects of, on subsequent
action of ammonia, 213
Wilkinson, Rev., on Utricularia, 398
Z.
Ziegler, his statements with respect to Drosera, 23 —, experiments by
cutting vessels of Drosera, 249
Zinc chloride, action on Drosera, 184