104 ELEMENTS OF BOTANY. 
(Fig. 90), by means of which the plant is enabled to climb. 
Occasionally a tendril takes the place of the whole leaf, and 
again tendrils occupy the place of stipules. The long petioles 
of some leaves aid the plant to climb by twining themselves 
about any convenient support, as is the case with the com- 
mon “nasturtium” (Tropeolum), Fig. 31. 
130. Leaves as Insect Traps. —In the ordinary pitcher 
plants (Fig. 92), the leaf appears in the shape of a more or 
V's y, 
Nb 
i 
Fia@. 92. Common Pitcher Plant.1 
At the right one of the pitcher-like Fie. 93.— A Leaf of Sundew.2 
leaves is shown in cross-section. (Slightly magnified.) 
less hooded pitcher. These pitchers are usually partly filled 
with water, and in this water very many drowned and decay- 
ing 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. 
1 Sarracenia purpurea. 2 Drosera rotundifolia. 
