50 



INTRODUCTION TO BOTANY 



Lianas, which were mentioned in the preceding section, get 

 their living without receiving from other plants any benefit 

 except that of position. The other groups (2-5) are discussed 

 in the following sections. 



50. Epiphytes. Unfortunately for students in temperate 

 climates, flowering epiphytes are mainly confined to the tropics. 

 The Spanish moss (fig. 31) is one of the few exceptions. A 

 visit to any large greenhouse in which orchids are kept will, 

 however, suffice to give a fair idea of the appearance of some 



FIG. 32. Indian pipe (Monotropa uniflora), a symbiotic saprophyte 

 The plants are white from lack of chlorophyll 



of the most characteristic plants which live upon the trunks 

 or branches of trees. Since these plants usually have little or 

 no permanent water supply about their roots, they must be 

 provided with means of absorbing water rapidly during rains, 

 _and of retaining it between one rainfall and the next. The 

 Spanish moss, which is rootless, takes up water along the 

 surface of the stems by the aid of special absorbent hairs 

 which grow from the epidermis. This plant can become almost 

 dried up without permanent injury. Other epiphytes, as 

 orchids, have specialized water-absorbing tissues upon root, 

 stem, or leaf surfaces, and from these tissues water escapes 

 slowly in dry weather. 



