122 BRITISH PLANTS 



on oaks, stonecrop on the aged branches of trees, and 

 various ferns, especially the polypody. The true epi- 

 phyte, however, is a xerophyte amid vegetation markedly 

 hygrophytic. It has a special mode of seed-dispersal, 

 for the seeds have to be lifted and deposited in places 

 far above the ground-level. They are exceedingly small 

 and light, as in orchids, or they are enclosed in fleshy 

 and sticky fruits, which birds carry and drop among the 

 branches of the trees. 



CKmbing plants and epiphytes which use other plants 

 for support are said to form guilds with them. Without 

 their aid climbers would fail to develop. Epiphytes, on 

 the other hand, can and do grow in soil, if there is no 

 vegetation around to obscure the light. 



