1915] 



OVERHOLTS — STUDIES IN THE POLYPORACEAE 723 



the rest were good specimens of the thin form known as T. 

 piceinus. There is no doubt in the writer's mind that all 

 these sporophores came from a common mycelium. In 1914 

 a similar find was made, the substratum being an old spruce 

 log. Portions of these two collections are preserved in the 

 writer's herbarium. Attempts were later made to sepa- 

 rate the specimens in these collections by means of micro- 

 scopic characters, but it was found to be impossible. In view 

 of these observations it is seen that the recently expressed 

 opinion of Meinecke 1 that the variation in shape is due to the 

 host, is not true for the fungus, as it sometimes occurs in 

 Colorado. 



In some localities it may be more convenient to consider 

 the thin form as a variety of T. Pini, for it must be admitted 

 that the two forms do not always grow in such close associa- 

 tion as described above. Yet the evidence is clear that they 

 cannot be regarded as distinct species. 



The writer believes that it will add to the clearness of the 

 general situation in the Polyporaceae to include in the genus 

 Fomes all perennial plants of whatever structure. This not 

 only simplifies the definition of the genus Fomes, but also 

 gives a clearer idea of the genus Trametes. As it has been 

 commonly understood, the genus Trametes is a very poorly 

 defined one, and any attempt to make its limits clearer is a 

 step in the right direction. The transfer of this species to 

 Fomes has already been made by Lloyd 2 . The species is here 

 described under that name. 



1. Fomes Pini Thor. ex Lloyd. 



Sporophores very variable, the variations grouping them- 

 selves as follows: 



Typical form: Sporophore perennial, often ungulate, 



X 4-20 X 1-15 cm., at first tawny and with elevated 

 zones of appressed tomentum, becoming blackish and glabrous, 

 the surface cracking or becoming rough and irregular ; context 

 not more than 5 mm. thick, tawny or ochraceous tawny, woody ; 

 tubes 2-6 mm. long each season, the mouths ochraceous to 



1 Forest tree diseases common in California and Nevada, p. 43. 1914. 

 »Syn. Fomes, p. 275. 1915. 



