76 



THE DESTRUCTIVE AGENTS OF FORESTS. 



tural periodicals, through bulletins issued and practical demon- 

 strations made by the Agricultural Experiment Stations, and 

 through instruction in the State Universities and in the public 

 schools, even the farmers that are the farthest removed from the 

 centers of population have become more or less familiar with 

 their crop diseases and the methods of controlling them. For the 

 reasons given, therefore, a simple discussion of the fungous dis- 

 eases of forest trees should be readily understood and fully ap- 

 preciated by any readers into whose hands it may fall. 



"Fungi are a class of low plants, possessing no coloring mat- 

 ter, which consist of fine threads called hyphae. many hyphae 

 forming the mycelium. The mycelium grows in or upon dead or 

 living organic matter, from which it extracts certain food sub- 

 stances. After a sufficient quantity has been absorbed, provided 

 that conditions are favorable, fruiting bodies are formed which 

 develop the spores. The fruiting bodies of the larger fungi found 

 on trees are generally known as sporophores".* 



^fany of the common fungi are parasites upon other living 

 plants, called their hosts, and live entirely at the latters' expense. 

 Others that derive their food materials from dead and decaying 

 organic substances are known as saprophytes. 



The large "brackets" or "punks", referred to above as 

 "sporophores", are not themselves the fungi, but bear somewhat 

 the same relation to the whole fungus plant that ordinary fruits 

 and flowers bear to the trees and vines upon which they grow. In 

 other words, when the fruiting part of a fungus appears, it is 

 unmistakable evidence that the vegetative part of the fungus has 

 reached an advanced stage in its life and has doubtless already 

 worked great injury to its host. 



Fungi do not produce true seeds but countless numbers of 

 minute bodies (spores), which answer the same purpose as seeds, 

 are scattered from their fruiting organs. When spores find a 

 suitable lodgment they begin to grow, sending slender threads 

 (hyphae) or their feeding branches (haustoria) into living or 

 dead tissues and continue to grow as described in the above 

 quotation. 



It is not considered advisable, if indeed it were possible, to 



♦"Fungous Diseases of Forest Trees" — H. Von Schrenk. 



