A STUDY OF LEAVES. 



39 



The Pitcher-Plants roll their 

 leaves for the purpose of holding 

 water. The Sarracenia drowns 

 insects in its pitcher, preventing 

 them from escaping by stiff hairs 

 which turn inward at its mouth. 



The pitcher is formed by the 

 edges of the winged petiole unit- 

 ing. 



The Sarracenia. 



Nepenthes has a cover to its 

 pitcher, to prevent the water from 

 evaporating. This lip opens when 

 it rains, and closes in dry weather. 

 The water is not for killing insects, 

 but to nourish the plant. 



Air-Bladders are little sacks 

 filled with air for the purpose of 

 holding water-plants up near the 

 surface. They are generally formed 

 of leaf-lobes. 



The Nepenthes. 



