322 UTRICULARIA NEGLECTA. [Chap. XVI L 



The bladders offer the chief point of interest. There are 

 often two or three on the same divided leaf, generally near 

 the base; though I have seen a single one growing from the 

 stem. They are supported on short footstalks. When fully 

 grown, they are nearly -^ of an inch (2.54 mm.) in length. 

 They are translucent, of a green colour, and the walls are 

 formed of two layers of cells. The exterior cells are polyg- 

 onal and rather large; but at many of the points where the 

 angles meet, there are smaller rounded cells. These latter 

 support short conical projections, surmounted by two hemi- 

 spherical cells in such close apposition that they appear 

 united; but they often separate a little when immersed in 

 certain fluids. The papillte thus formed are exactly like 

 those on the surfaces of the leaves. Those on the same 



Fio. 18. 



(UtriaUaria neglecta.) 



Bladder ; ranch enlarged, c, collar indistinctly seen throngh the walls. 



bladder vary much in size; and there are a few, especially 

 on very young bladders, which have an elliptical instead of 

 a circular outline. The two terminal cells are transparent, 

 but must hold much matter in solution, judging from the 

 quantity coagulated by prolonged immersion in alcohol or 

 ether. 



The bladders are filled with water. They generally, but 

 by no means always, contain bubbles of air. According to 

 the quantity of the contained water and air, they vary much 

 in thickness, but are always somewhat compressed. At an 

 early stage of growth, the flat or ventral surface faces the 



