M in diameter, colored like the fnictifica- M'liOTllImll 

 tion, stiff, not nodose-septate, forming a 



1918] 



BURT THELEPHORACEAE OF NORTH AMERICA. X 341 



Thiimen, Myc. Univ., 512 (without description). Probably 

 not Corticium simulans Berk. & Broome, Linn. Soc. Bot. Jour. 

 14 : 72. 1873. Hymenochaete simulans (Berk. & Rav.) Peck, 

 N. Y. State Mus. Rept. 49 : 34. 1897 (without description) ; 

 V. Hohn. & Litsch. K. Akad. Wiss. Wien Sitzungsber. 116 : 

 775. 1907. 



Type : authentic specimen from Karsten in Burt Herb. 



Fructifications resupinate, effused, scattered, orbicular at 

 first, then laterally confluent, thin, dry, adnate, not cracked, 

 drying clay-color to antique brown, the margin thinning out; 

 in structure 100-140 /x thick, composed of 

 loosely interwoven, suberect hyphae 3-4 v 



homogeneous layer, without a dense zone Fig. is 



from substratum to hymenium, and bear- h. arida. 



ing scattered setae in the upper portion ^^thenUc^spedmen *^ 

 of the layer; setae 30-75x6-8 /*, emerg- 

 ing up to 35 /x, not numerous, tapering upward; spores in 

 spore collection from Swedish specimen white, even, allantoid, 

 6-7 X 2 /* as seen in side view, 2|-3 /n broad in front view, and 

 6-7x3^-4 /x, flattened on one side in American specimens. 



Fructifications at first 2-3x2 mm., later laterally confluent 

 over areas 9x1-14 cm. 



On bark of dead branches of Corylus, Ostrya virginica, and 

 Vaccinium arhoreum. Finland, Sweden, Vermont to South 

 Carolina, and in Michigan. October to April. 



The fructifications of H. arida are at first small, scattered, 

 and suborbicular and later become confluent and elongated so 

 as to resemble closely in aspect and color Coniophora arida. 

 The spores of American collections are about twice the 

 breadth of those of European specimens cited, but the agree- 

 ment between the European and American specimens is so 

 close in general aspect and in the very simple structure of 

 the fructification in section that I believe the American and 

 European specimens are of the same species. The distinguish- 

 ing characters of H, arida are its resemblance in aspect to 

 Coniophora arida, structure consisting of a single, homo- 



