26, 



of the European''epiphytes'',He regards the factors 

 v/hich help the existence of the "epiphyte" as 

 "both external smd internal, The external factor is 

 the ability to grow in a shady and humid environment; 

 the internal, the hereditary adaptaion to withstand 

 dessication, These are the only adaptations possessed 

 "by the "accidental epiphytes ".Czapek (s) studied the 

 morphology and physiology of epiphytic orchids and 

 found that the roots showed positive geotropism.Some 

 orchids,however, possess roots which are negatively 

 helio tropic, When aerial roots were grown in the dark 

 numerous root hairs were developed, Furthermore, he foimd 

 that only liquid water is absorbed by the roots in 

 appreciable amount, The velamen may condense atmospheric 

 moisture but the quantity of such moisture is so 

 small that the velamen can not be considered chiefly as 

 a condenser of atmospheric humidj.ty, but should be regarded 

 primarily as a water absorbing organ, Through a continual 

 absorption of small quantities of water, the roots 

 really perform the function of supplying the plant 

 with the necessary amount of v/ater. 



Of the distribution of the epiphytes in Jamaica, 

 Shreve (26) says {p.l87) : "The trees of the upper 

 slopes have the same epiphytic flora that would be 

 found in the upper two- thirds of the trees of the 

 ravines,The trees of the ridges and peaks have only 

 those that are characteristic of the uppermost 

 third and the midheight species are restricted in 



