Cuar. XVI STRUCTURE OF THE BLADDER. 397 
points. Hach point is tipped by a short, straight 
bristle ; and slight notches on the sides of the 
leaves bear similar bristles. On both surfaces there 
are many small papille, crowned with two hemi- 
spherical cells in close contact. The plants float 
near the surface of the water, and are quite destitute 
of roots, even during the earliest period of growth.* 
They commonly inhabit, as more than one observer 
has remarked to me, remarkably foul ditches. 
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 
vs of an inch (2°54 mm.) in length. They are trans- 
lucent, of a green colour, and the walls are formed 
of two layers of cells. The exterior cells are poly- 
gonal and rather large; but at many of the points 
where the angles meet, there are smaller rounded cells. 
These, latter support short conical projections, sur- 
mounted by two hemispherical cells in such close 
apposition that they appear united; but they often 
separate a little when immersed in certain fluids. The 
papillee thus formed are exactly like those on the 
surfaces of the leaves. Those on the same 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. 
* T infer that this is the case om Lentibulariacex,” from the 
from a drawing of a seedling ‘Videnskabelige | Meddelelser,’ 
given by Dr. Warming in his Copenhagen, 1874, Nos. 3-7, pp, 
paper, “ Bidrag til Kuudskaben 33-58. 
