DEW AND RAIN : BLADDERWORTS 77 



Humboldtii are epiphytes, but only in a restricted sense, 

 for they Hve in the water cisterns of a giant bromeHad in 

 Guiana. They can be cultivated in damp moss. Several 

 species, e.g. U. retiif omits and the Singalese U. bifida, 

 inhabit moss ; U. Jainesoniana creeps on the bark of trees. 

 The Utricularias possess no roots, but they send through 

 the moss vigorous runners which bear bladders, and which 

 serve as water-absorbing organs. In U. bifida, short stout 

 " rhizoids," probably of leaf nature, are formed ; these do 

 not seem to play any important absorbing role. The 

 related terrestrial genus Genlisea absorbs water by subter- 

 ranean bladder-bearing organs of leafy nature. The mor- 

 phology of the vegetative organs of the Utriculariaceas will 

 be referred to in another connection. 



