120 ELEMENTS OF BOTANY 
Fic. 85. Blade of Leaf 
of Sundew. (Some- 
what magnified.) 
140. Carnivorous Plants. —In the 
ordinary pitcher-plants (Fig. 83) the 
leaf appears in the shape of a more or 
less hooded pitcher. These pitchers 
are usually partly filled with water, 
and in this water very many drowned 
and decaying insects are commonly 
to be found. The insects have flown 
or crawled into the pitcher, and, once 
inside, have been unable to escape on 
account of the dense growth of bristly 
hairs about the mouth, all pointing 
inward and downward. How much 
the common American pitcher-plants 
depend for nourishment on the drowned insects in the 
pitchers is not definitely known, but it is certain that some 
of the tropical species 
require such food.? 
In other rather com- 
mon plants, the sun- 
dews, insects are 
caught by a sticky 
secretion which pro- 
ceeds from hairs on the 
leaves. In one of the 
commonest sundews 
the leaves consist of a 
roundish blade borne 
on a moderately long 
1 Where the Sarracenia is 
abundant it will be found in- 
Fic. 86. Leaves of Sundew. (Some- 
what magnified.) 
The one at the left has all its tentacles closed 
over captured prey; the one at the right 
has only half of them thus closed. 
teresting and profitable to make a careful class study of its leaves. See 
Geddes’ Chapters in Modern Botany, Chapters I and IL, 
