1918] 
BURT—THELEPHORACEAE OF NORTH AMERICA. X 341 
Thümen, 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. Hóhn. & Litsch. K. Akad. Wiss. Wien Sitzungsber. 116: 
775. 1907. 
Type: authentie 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 џ thick, composed of 
loosely interwoven, suberect hyphae 5-4 da y died 
p in diameter, colored like the fructifica- AES 
tion, stiff, not nodose-septate, forming a n 26% Y 
homogeneous layer, without a dense zone Fig. 15 
from substratum to hymenium, and bear- H. arida. 
ing scattered setae in the upper portion uic rei 
of the layer; setae 30-75X 6-8 и, emerg- 
ing up to 35 и, not numerous, tapering upward; spores in 
spore collection from Swedish specimen white, even, allantoid, 
6—7 x2 y as seen in side view, 24-3 y broad in front view, and 
6-7 x 34-4 и, flattened on one side in American specimens. 
Fructifications at first 2-32 mm., later laterally confluent 
over areas 9X1-14 cm. 
On bark of dead branches of Corylus, Ostrya virginica, and 
Vaccinium arboreum. 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- 
