320 THE STORY OF PLANT LIFE 



the Bird's Nest Group differs in not possessing green | 



leaves. 



Yellow Bird's Nest (Monotropa Hypopitys). 



This plant is one of those that obtain their main 

 nourishment not directly, like green plants, by carbon 

 assimilation, the plant being yellow in this case or 

 white, but indirectly from other plants, living entirely 

 on the products that other plants prepare for them. 

 They are thus called saprophytes. Parasites derive 

 part of their nourishment from other plants, but are 

 sometimes when semi-parasites green and thus work 

 for themselves, and in return for help derived from 

 their hosts, as the plants they sponge upon are 

 called, they give something back. Saprophytes live 

 on decaying matter and absorb the products of 

 fermentation. They take in carbon from the soil in 

 the form of organic compounds. Such plants do 

 not, therefore, require leaves, and in their place they 

 usually possess scales. Some of these plants, as the 

 parasitic Toothwort, have the scales modified to 

 serve as insectivorous contrivances. 



When plants live in a state of partnership with 

 others they are symbiotic, living together for mutual 

 benefit, as in the case of Lichens, where the fungus 

 provides a lodging for the imprisoned algal element 

 which provides nutriment in return for its lodging. 



The Yellow Bird's Nest possesses short, fleshy, 

 much-branched roots which are covered up by the 



