ix] "GILL-TUFTS" OF OENONE 119 



of the water exposes them to entire or partial desiccation, has 

 been repeatedly noted by travellers. Barrington Brownl^Mn 

 describing his explorations up the Cuyuni River in British 



Fig. 81. Oenone multibranchiata, Matthiesen. Part of flowering plant shoAving the 

 numerous "gill-tufts" on the upper surfaces of the leaves. [Matthiesen, F. (1908).] 



Guiana, mentions the occurrence of Podostemaceae on the 

 rocks under water where the current runs strongest, and adds, 



^ Brown, C. Barrington (1876}. 



