98 



SOCIAL CONJUNCTIVE SYMBIOSIS 



61. Hemi-epiphytes and Pseudo-epiphytes.— Hemi-epiphytes are 

 plants that are epiphytic, and therefore symbiotic, during only a 

 part of their lives. The strangHng fig is a notable example (Figs. 40 

 and 41). The seeds of the fig germinate on the bark of a host and 

 the young fig plant starts its life as an epiphyte. Soon, however, 

 some of its roots begin to grow downward and around the trunk of 

 the host. These roots become thick and flattened and the host plant 

 is often actually strangled by them (Fig. 42) . Eventually they reach 



Fig. 44.— Large fig tree with Palmetto host almost killed. (Photograph by 

 William Trelease. Courtesy of Dr. George T. Moore and the Missouri Botanical 

 Garden.) 



the soil and the fig then becomes an independent plant, no longer 

 epiphytic (Figs. 43, 44 and 45). 



Ordinary soil plants are often found growing in crotches or 

 knotholes of trees where a little soil has collected. These are called 

 pseudo-epiphytes. Their symbiotic relations to the host plant are 

 comparal^le to those of true e])iphytes. 



62. The Epiphyte Habit.— Many epiphytes*seem to be capable of 

 growing on most any supporting host. Some can even grow upon 

 non-living supports. Spanish moss {Tillandsia), for example, may 



