30, 



IVilCBASUEElCLNT,AJVTD'GOI-,TPARISOU OP EIIVIR0M5E1TTAL 

 CONDITIONS, 



A. Climatic Conditions 

 A review of the botanical literature shows 



that the early students of epiphytes studied them 



priniarily to determine the means "by which these 



plants reach the ^itr trees ¥;hich bear them.This led 



to the study of dissemination of various seeds, Later 



the investigation of the nutrition of the epiphytes 



and of the structure of the roots of the epiphytes in 



search of a possible raycorhizal association was 



begun.Certain investigators studied the true tropical 



epiphytes, while others were studying the "false" 



epiphytes that occurred in Europe.The results showed 



that the true air plants have special peculiarities 



of structure which enable them to live and to grow 



without any connection with the soil. The "false" 



epiphytes, on the contrary, have no such Rdar'''itions 



and few reach maturity on their supporting tree, Only 



those reach maturity, of course, which afjf^ter a time 



succeed in making connection with the earth through 



the tissues of its support, Finally, the physiological 



and ecological phases of the problem have attracted 



the attention of recent workers who have attempted 



to determine the osmotic concentration of the sap 



of epiphytes and the conditions under which tiB 



air plant grows best, It seems that the prevailing 



