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BOTANY: PRINCIPLES AND PROBLEMS 



best-known example. The structural modifications of such 

 forms are in general similar to those which distinguish parasites. 

 The ability possessed by both parasites and saprophytes to use 

 complex organic substances directly is nearly or quite lacking 

 among ordinary green plants, which are able to take through 

 their roots only simple inorganic salts. 



Fig. 93. — Saprophytes. The Indian Pipe (Monotropa). 



Epiphijtes. — A third type of relationship between one plant 

 and another, and one which is free from destructive consequences, 

 is presented by those species which grow upon the bodies of 

 other plants but are not parasitic thereon. Such plants are 

 known as epiphytes (Fig. 94) and arc especially common in dense 

 tropical forests. Many ferns and orchids display this habit of 

 growth. The roots of epiphytes have no connection with the 

 ground and do not enter the living tissues of other plants, and in 

 consequence they are often modified to draw moisture directly 



