82 UNIVERSALITY OF DEGENERATIVE EVOLUTION 



Iii Utricidaria this function is exercised by the 

 leaves (as in U. intermedia), or by certain parts 

 of the leaves (U. vulgaris). In Nepenthe, however, 

 another and different assimilative organ is exhibited. 

 This consists of two lateral herbaceous growths, which 

 are not formed from the blade, but arise from the 

 petiole. In between the receptacle and the en- 

 larged portion of the petiole is a part in which 

 the petiole has assumed the function of a tendril. 

 While the receptacle is in process of formation, this 

 tendril twines itself round a support in order to 

 obtain the additional strength that will be required 

 later on to uphold the receptacle when full of diges- 

 tive juice. 



(c) Drosera. The leaves of the sundews (Drosera 

 rotundifolia, D. longifolia, etc.) are furnished with 

 a great number of emergences, each of which ter- 

 minates in a digestive gland. There is a large 

 drop of sticky fluid at the end of each gland, 

 and these 'drops, which sparkle in the sunlight, 

 have given the plant its name (Eos solis = sundew) 

 (fig. 46). 



These emergences contain very little chlorophyll. 



"A plant of Drosera, with the edges of its leaves curled 

 inwards so as to form a temporary stomach, with the glands 

 of the closely-inflected tentacles pouring forth their acid 

 secretion, which dissolves animal matter afterwards to be 

 absorbed, may be said to feed like an animal." 



Darwin, Insectivorous Plants, p. 18. 



This adaptation to a carnivorous diet has not 



