Fungus Diseases 



41 



most common and the most insidious, since their myceHum 

 penetrates deeply into the body of the tree out of reach. 

 Since the trunk of the tree, the wood, is mostly dead tissue, 





Fig. II. — Three species of rot fungi. When these fruit-bodies appear at 

 the base or on the wounds of a tree, the interior is usually all decayed, and 

 help comes too late, (.\fter Murrill, from Cornell University Bulletin, No. 

 205-) 



they do not impair to any great extent the living portion. 

 Yet they are not mere saprophytes, for they really feed on 

 the wood, absorbing cell-walls and cell contents, and to 

 some extent impair its functions in the conduction of water. 

 But their main damage lies in destroying the firmness of 



