Vesicles of the Utricularifo. 393 



among the cells of the parenchyma. The exterior globule after- 

 wards becomes filled with a brown matter. Schlciden (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 

 uie 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 aeriferous canals of the petioles of the Nynjphrcacere. 



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 tlic 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. These 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 Utricvlaricc. 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. Utricularia 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. 



