EPIPHYTES 



95 



soil. Furthermore, if such a plant climbs upon a slow growing host 

 it may in time become too heavy for its supporting plant and this in 

 time may result in the downfall of both symbionts (Fig. 37). Some- 

 times the leaves of the liana overtop those of the host and cut off 

 so much light that the host is gradually weakened and thus the down- 

 fall of both is hastened. (Fig. 36.) 





Fig. 41.— Palmetto with two well-established figs, showing strangling roots 

 that have reached the soil. (Photograph by William Trelease. Courtesy of 

 Dr. George T. Moore and the Missouri Botanical Garden.) 



GO. Epiphytes.— Epiphytes are i)lants tliat live upon other plants 

 for su])port only. The>- are distinguished from i)arasites by the fact 

 that they do not obtain food or food materials from the host plant. 

 They manufacture their own food from carbon dioxide and water, 

 and mineral salts that are derived mainly from wind blown and 

 water-borne materials. They thus differ from ordinary land plants 



