THE POLYFORACEAE OP WISCONSIN. 19 



The rot produced by Trametes pini advances very slowly in white 

 pine but much more rapidly in tamarack and hemlock. One tam- 

 arack about ninety-five years old, measuring twelve inches in diameter 

 four feet above the ground, had its interior wholly destroyed to a 

 height of nearly fifty feet, except a thin shell underneath the bark 

 about one-half inch in thickness. This, perhaps, accounts for the 

 fact that the pilei are so abundant on tamarack and so rare on white 

 pine. It is very probable that the formation of pilei is dependent not 

 so much on the amount of mycelium produced within the wood as 

 upon its ability to get to the surface. I am of the opinion that this is 

 the case with several other forms. While at Hazelhurst I wounded a 

 birch infected with Fomes nigricans cutting into the wood until the 

 decay was reached. In less than two weeks small pilei were forming 

 on the wound. The same result can be obtained with F. fomentarius, 

 Polystictus pergamenus, Fomes applanatus and probably also with 

 Trametes pini. 



Fomes ungulatus (Schaeff.). 



This is a large woody fungus. It is possible that at least four forms 

 of it have been described under as many different names: F. pinicola 

 (Schwartz), F. ungulatus (Schaeff), F. marginatus Fries and F. pini- 

 canadensis Schw. 



The form most commonly found here agrees best with Fries' de- 

 scription of Fomes marginatus. This is the large applanate form, 

 often growing to one foot or more in width. The upper surface of this 

 form is hard, rough, concentrically sulcate, and the oldest portion is 

 black. The youngest sulcation is blood red with a creamy white mar- 

 gin. The context is corky or hard, wood-colored and zonate. The 

 tubes are stratified and about one centimeter in length, and of the 

 same color as the context. The young growing margin, as well as the 

 pores, stain reddish or pink when touched or bruised. 



This fungus is widely distributed, especially through northern Wis- 

 consin, but it has been found as far south as Madison, where one speci- 

 men was found in 1899 growing on hickory. It was found especially 

 abundant in the Star Lake region, where as stated before, about eighty 

 per cent of the fir trees are infected. One fir tree only ten years old 

 and a little more than an inch in diameter, when cut down, was found 

 decayed at the center, from the roots, into which the decay extended 

 for about six or seven inches to about three feet above the ground. 

 This tree was simply cut down at random and bore no marks or signs 

 of infection or wounds above ground. Although there was so much 



