104 ELEMENTS OF BOTANY. 



(Eig. 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" (Tropseolum), Mg. 31. 



130. Leaves as Insect Traps. — In the ordinary pitcher 

 plants (Fig. 92), the leaf appears in the shape of a, more or 



Fig. 92. — Common Pitcher Plant.' 

 At the right one of the pitoher-like Pig. 93. — A Leaf of Sundew.' 



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. 



^ Sarracenia purpurea. ^ Drosera rotwndi/olia. 



