LEAVES AND THEIR USES 



237 



(Fig. 142). Each leaf-blade of this 



plant is curved into the shape of a 



pitcher which catches and holds rain 



water. Insects, attracted by nectar 



that is produced about the mouth of 



the pitcher, crawl into it. They are 



prevented from crawling back by 



strong, pointed hairs inside, which 



are turned downward. Finally the 



insects are drowned in the liquid in 



the pitcher. This liquid contains 



enzyms, produced by some of the 



cells that line the pitcher. The 



enzyms digest (that is, change to a 



soluble form) such parts of the dead 



insects' bodies as the plant can use -,.^„ . 



^ riG. 142. — A, an m- 



for food, and the leaf cells absorb sect-catching leaf of the 



this dissolved food from the water, common pitcher plant 



T-c, 1 1 J. r J.1 • (Sarracenia). B, a cross 



Pitcher plants of other species are Action through the middle 



found in the southern United States, of the leaf, 

 on the Pacific coast, and in the 

 tropical parts of 

 the eastern hemi- 

 sphere. 



The "sun- 

 dews " catch in- 

 sects in a very 

 different way. 

 The edges and 

 the upper surface 

 of each leaf bear 

 thick glandular 

 hairc; ('P^^p ta2) ^^^' ^'^^' — Leaves of a sundew (Drojcra rotewii- 



,, folia): A, after the leaf has been stimulated by 

 On the swollen tj^g touch of an insect ; B, a leaf in the unstimu- 

 end of each hair lated condition. After Kemer. 



