202 



VEGETABLE PHYSIOLOGY 



These are marsh plants having their leaves arranged in 

 rosettes, which spring apparently from the surface of the 

 soil, and from the centre of which arises a single flower 

 stalk. Each leaf is modified to form a curious pitcher-like 

 body (fig. 95), furnished with a 

 kind of lid. The pitchers are 

 generally conspicuously coloured, 

 while the lid, which is the lamina 

 of the leaf, often bears hairs which 

 secrete honey to attract the prey. 



The inner surface of the pitchers 

 is lined with slippery recurved hairs 

 which make it impossible for an 

 insect to climb out of it after once 

 entering. Insects are attracted by 

 the honey, and, venturing upon 

 these hairs, slip down to the bottom 

 of the pitcher, from which escape 

 is impossible. The pitcher contains 

 a quantity of water, due either to 

 the entrance of rain or possibly to 

 some extent secreted by the sur- 

 face of the pitcher. The insects 

 become drowned in this liquid and 

 undergo decomposition. Frequently 

 a pitcher will contain so many that 

 the products of their putrefaction 

 become offensive. They are ab- 

 sorbed by the cells of the interior. 

 Certain other pitcher-plants show a still further ad- 

 vance in their method of obtaining proteid supplies. They 

 possess similar means of attracting insects and alluring 

 them to their death, but they do not depend on the 

 slow process of putrefaction for the decomposition of 

 their prey. Instead of this, they secrete and pour out a 

 definite digestive fluid possessing properties like those of 

 the secretions of the stomach and pancreas of the higher 



FIG. 95. LEAF OF Sarracenia, 



MODIFIED TO FORM A 



PITCHER. (After Kerner.) 



