THE LEAF. 



25 



downward. They are generally half full of a liquid into 

 which insects may fall and become macerated, and their juices 

 are then absorbed by the plant. The Drosera is also carniv- 

 orous, feeding on small insects which alight on and are held 

 fast by the viscid tentacles on the upper side of the leaf. 



Fig. 5. 



Fig. 6. 



The leaves of Dionoea (Fig. 5) have at the top, two or three 

 lobes furnished with a marginal row of stout bristles, and 

 three or four slender ones on the upper surface. When the 

 bristles on the upper surface are touched by a small insect, 



Fig. 7. 



Fig. 8. 



the lobes suddenly close in upon it and the prisoner is then 

 digested and consumed. 



5. The leaves are said to be alternate (Fig. 6) when there 

 is a single leaf at each node or joint of the stem. Examples 



c 



