254 



LEAVES 



Fig. 92. 



(See Figures 92 and 93.) In this plant it is the long out- 

 growths of the leaf surface and not the leaf itself which 

 close down upon the insect. The 

 insect is first caught, however, by 

 getting its feet entangled in a sticky 

 substance which is produced at the 

 swollen ends of the outgrowths. 

 The leaf acts somewhat like a bit 

 of sticky fly paper. This plant gets 

 the name sun-dew from the dew- 

 like appearance of the sticky drops ; 

 they do not evaporate in the sun 

 like ordinary dew. 



How does the food derived from 

 the captured insects get into the 

 body of the plant ? As you already 

 know, it can enter only in liquid 

 form. The change of food from a solid into a liquid con- 

 dition is accomplished by the process called digestion. 

 The captured insects are digested where they are caught. 

 Certain fluids which the plant manufactures act upon 

 them much as the digestive fluids act upon the food which 

 you eat. After this process, the molecules of food enter * 

 the plant as solutes. 



These insect-catching plants all possess chlorophyll. 

 They appear to be as capable of photosynthesis as many of 

 their neighbors which do not catch insects. It is estimated 

 that the food which they derive from insects is small in 

 amount as compared with the food which they obtain by 

 the more usual methods. Insect catching appears to 

 supplement their diet; it does not appear to be their 

 main source of food. The conditions which have caused 



— Plant of sun-dew 

 {Drosera) . 



