CHAPTER VII 



FUNGI 



76. General characters. The Fungi do not contain 

 chlorophyll, and this fact forms the sharpest contrast be- 

 tween them and the Algae. The presence of chlorophyll 

 enables the Algae to be independent of any other organism, 

 since they can manufacture their food out of carbon dioxide 

 and water ( 14). The absence of chlorophyll compels 

 the Fungi to be dependent upon other organisms for their 

 food. This food is obtained in two general ways: either 

 (1) directly from living plants and animals, or (2) from 

 organic waste products or dead bodies. In case a living 

 body is attacked, the attacking fungus is called a parasite; 

 and the plant or animal attacked, the host. In case the food 

 is obtained in the other way, the fungus is called a sapro- 

 phyte. For example, the rust that attacks wheat is a 

 parasite, and the wheat is the host; while the mold which 

 often develops on stale bread is a saprophyte. 



In case parasites attack valuable plants or animals they 

 may be very harmful, giving rise to destructive diseases. 

 The United States Government has expended a great deal 

 of money in studying such Fungi, trying to discover some 

 method of destroying them or of preventing their attacks. 

 There is an interesting selective power exhibited by many 

 parasites, that restrict themselves to certain plants and 

 animals, or even to certain organs. Many, however, are 

 more general in their attacks; and some can live as para- 

 sites or saprophytes as occasion demands. It must not be 



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