120 ESSENTIALS OF BOTANY 
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 
Fic. 85. Blade of Leaf hairs about the mouth, all pointing 
of Sundew. (Some- . 
what magnified.) 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.1 
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 @ — Fy¢, 86. Leaves of Sundew. (Some- 
roundish blade borne what magnified.) 
on a moderately long The one at the left has all its tentacles closed 
over captured prey; the one at the right 
1 Where the Sarracenia is _ has only half of them thus closed. 
abundant it will be found in- 
teresting and profitable to make careful class study of its leaves. See 
Geddes’ Chapters in Modern Botany, Chapters I and II. 
