CHAPTEE XVIII 



THALLOPHYTES : FUNGI 



177. General characters. — In general, Fungi include Thal- 

 lophytes which do not contain chlorophyll. From this fact 

 it follows that they can not manufacture food entirely out 

 of inorganic material, but are dependent for it upon other 

 plants or animals. This food is obtained in two general 

 ways, either (1) directly from the living bodies of plants or 

 animals, or (2) from dead bodies or the products of living 

 bodies. In the first case, in which living bodies are at- 

 tacked, the attacking fungus is called a parasite, and the 

 plant or animal attacked is called the host. In the second 

 case, in which living bodies are not attacked, the fungus is 

 called a saprophyte. Some Fungi can live only as parasites, 

 or as saprophytes, but some can live in either way. 



Fungi form a very large assemblage of plants, much 

 more numerous than the Algae. As many of the parasites 

 attack and injure useful plants and animals, producing 

 many of the so-called " diseases," they are forms of great 

 interest. Governments and Experiment Stations have ex- 

 pended a great deal of money in studying the injurious 

 parasitic Fungi, and in trying to discover some method of 

 destroying them or of preventing their attacks. Many of 

 the parasitic forms, however, are harmless ; while many of 

 the saprophytic forms are decidedly beneficial. 



It is generally supposed that the Fungi are derived from 

 the Algae, having lost their chlorophyll and power of inde- 

 pendent living. Some of them resemble certain Alga? so 



closely that the connection seems very plain : but others 

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