226 



Bulletin 193. 



past when the fungus entered, the mode of its entrance and prog- 

 ress, as well as the probable cause of the wound which provided 

 the entrance court for the tree enemy. In a number of cases these 

 have been worked out quite satisfactorily. Tlie studies have been 

 made in New York State, chiefly at Ithaca and in the forests of the 

 Adirondack mountains. 



A word mii^ht be said at the outset in res^ard to the relation of 

 these wood destroying fungi to others, as well as in regard to their 

 structure. They are among the higher fungi and belong to the 

 larger group known as the Ilymenomycetes to which the mushroom 

 also belongs. In fact it is becoming customary with some to apply 



the term " mushroom " 

 to all of the Hymeno- 

 7)iycetes. However 

 widely these plants 

 differ in their form and 

 structure, they all agree 

 in the general character 

 of their fruiting surface. 

 It forms a thin layer or 

 " membrane," covering 

 definite parts of the 

 fruit body, and consist- 

 in o; of innumerable club- 

 shaped cells standing 

 side by side. Each one of 

 these club-shaped cells is 

 called a hasidium, and 

 usually bears four spores. 

 There are several 

 large families, or orders 

 in the group. I will 

 call attention to a very 

 few in each family in 

 order to show more 

 definitely the form and general character of the species examined 

 here. In one of these families the fruit body is often spread over 



56. — Polyporus horealis. Fruit bodies groicing 

 from wound on Jiemlock spruce. 



