Vesicles of the Utricularic. 393 
among the cells of the parenchyma. The exterior globule after- 
wards becomes filled with a brown matter. Schleiden (Grund- 
ziige, 4th edit. p. 397) observed the flattened cells on the out- 
side of the utricles, but does not mention them on the leaves; 
and yet their presence on the leaf properly so called seems to 
me to be precisely an additional proof that the utricle is only 
an expansion and modification of the parenchyma. The quadri- 
fid hairs which line the interior of the utricles present a certain 
resemblance to the stellate hairs which occur on the inner sur- 
face of the aériferous canals of the petioles of the Nympheeacee. 
The intercellular passages of the leaves of Utricularia contain 
much gas, which causes them to appear black under the micro- 
scope; this black band is prolonged through the pedicel into 
the utricle. In plants exposed to light I have often observed a 
strong disengagement of gas (oxygen), the bubbles of which 
rose in the water for a long time, forming a nearly continuous 
gaseous thread; these bubbles of gas started from’ the angle of 
two segments of the leaf not far from a utricle. Similar bub- 
bles are likewise evolved at the extremity of the capillary seg- 
ments of the leaves. 
As regards the mushroom-like cells, in which the pileiform 
part is slightly constricted in the middle, and often divided into 
two, these seem to me to occupy the place of the stomata, and 
to play the part of glands ; in fact they present a great analogy 
to the glands which occur at the surface of the base of the vis- 
cous leaves of Pinguicula vulgaris. 'Phese glands likewise ter- 
minate superiorly in a little brown inflated hood, similar to that 
of a small mushroom, whilst the stem is colourless as in the 
corresponding organs of the Utricularie. The mucilage which 
covers the surface of the leaves of Pinguicula would correspond 
in its turn to that which fills the cavity of the young utricles. 
_ We have already seen that the utricles at first present an 
extremely pale-green colour; subsequently the green colour 
becomes more strongly marked. Ucricularie collected in the 
marshes of Jogny on the 18th of October, 1866, still presented 
a small number of green utricles; but most of them were of a 
violet or very dark blue colour. 
In these coloured utricles the angular (usually hexagonal) 
cells of the inner layer contain a coloured liquid passing from 
lilac rose-colour to blue violet ; these cells then resemble stained 
glasses surrounded by a slender thread of silver. The ceils 
which close the intercellular canals were either red or dark blue ; 
round them there extended, between the angular cells, a reddish 
tint. At this same period (October.1866) I found in the seg- 
ments of the leaves, side by side with the green cells containing 
chlorophyll- granules, cells the contents of which were pale red. 
