1915] 



OVERHOLTS — STUDIES IN THE POLYPORACEAE 715 



ferred to the genus Forties. F. Ellisianus was described from 

 Montana by Anderson in 1891, and redescribed as Polyporus 

 circumstans by Morgan from South Dakota in 1895. The 

 former species is abundant in the central and eastern United 

 States, growing only on the trunks of ash trees. The latter 

 species is found occasionally in the western United States, 

 growing only on trunks of Shepherdia. 



Lloyd has recently expressed the opinion that these two 

 species are identical, except for host, and he has so treated 

 them in his recent synopsis of the genus Fomes. The plants 

 are much alike in their old stages but I cannot agree with him 

 that Fomes Ellisianus is "exactly the same plant" as our 

 eastern species on the ash. First, there is the distinction in 

 host, but that of itself would not be important. Second, 

 plants of F. Ellisianus that are fairly mature have a decidedly 

 corrugated or radiate-rugose surface and a reddish tinge of 

 color. I have seen no indication of either of these characters 

 in F. fraxinophilus though I have been familiar with that 

 species for a number of years and have observed it in all 

 stages of growth. When the plants are several years old they 

 become similar in appearance and it would be an easy matter 

 to mistake the one for the other if the host were unknown. But 

 the characters pointed out here are believed to be amply 

 sufficient for retaining the two plants as distinct species. 



The following brief descriptions are appended : 



1. Fomes Ellisianus Anderson. 



Pileus convex to ungulate, 3-10 X 3-8 X 1.5-4 cm., pallid to 

 brown, radiate-rugose and with a reddish tinge when young, 

 black and usually somewhat rimose with age, sulcate ; context 

 pallid to wood-colored, punky to corky, 0.5-2 cm. thick; tubes 

 2-6 mm. long each season, 1 not distinctly stratified, the mouths 

 white or yellowish, averaging 2-3 per mm.; spores oblong- 

 ellipsoid to broadly ellipsoid, 6-8 X 4-5 n ; cystidia none ; 

 hyphae hyaline, 3-5 p. 



On Shepherdia in the west-central states. 



1 The tubes in this plant are sometimes continuous to a length of 1.5 cm., 

 but I do not believe that such lengths are attained in a single year's growth. 



