vm] EPIPHYTIC BLADDERWORTS 109 



Such a habitat would be impossible for the Bladderwort without 

 the help of the Bromeliad's store of water, while the rich fauna 

 of this water gives it every chance of catching suitable prey 1 . 

 In the observer's own words, the Utricularia "propagates 

 itself by runners, which it throws out from the base of the 

 flower stem; this runner is always found directing itself towards 

 the nearest Tittandsia, when it inserts its point into the water, 

 and gives origin to a new plant, which in its turn sends out 

 another shoot; in this manner I have seen not less than six 

 plants united." 



In British Guiana a similar case has been described 2 . A huge 

 aloe-like Bromeliaceous plant, Brocchinia cordylinoides, Baker, 

 grows inthe Kaieteur savannah. It may be fourteen feet high, 

 and, in older specimens at least, the crown of leaves is supported 

 on a tall bare stem. Floating in the water retained in the axils 

 of the leaves, is found a beautiful Utricularia (U. Humboldtii^ 

 Schombk.) "with flower stems 3 or 4 feet long, supporting its 

 many splendidly large violet flowers." This form of epiphytism 

 is not obligatory, since in Roraima, although both the Bromeliad 

 and the Utricularia occur, the Utricularia may live a terrestrial 

 life on marshy ground, instead of being associated with the 

 Bromeliad. 



Many of the unusual characteristics of the Utricularias are 

 shared by another flowering plant, extremely remote from them 

 in its affinities Aldrovandia vesiculosa, L., a member of the 

 Droseraceae. This plant has long had a peculiar fascination for 

 botanists, and a detailed memoir upon it by an Italian writer 

 appeared before the middle of the eighteenth century 3 . Like 

 the Bladderworts, Aldrovandia is rootless and free-floating, and, 

 but for its flowers, lives entirely submerged. It has a slender 

 axis bearing whorls of leaves; the older internodes and leaf 

 whorls die away successively, as new parts are formed at the apex. 



1 Goebel, K. (1891-1893). 



2 Im Thurn, E. F. and Oliver, D. (1887). 



3 Monti, G. (1747). For an analysis of this paper see Auge de Lassu 

 (1861). 



