1925] 



BURT THE THELEPHORACEAE OF NORTH AMERICA. XIV 299 



margin narrow, radiate-fibrillose; in section 100-200 \l thick, 

 not colored, the hyphae with walls gelatinously modified, in- 

 distinct, about 3 \L in diameter, ascending, densely crowded to- 

 gether and interwoven and with numerous gloeocystidia present ; 

 gloeocystidia sometimes pyriform but usually more elongated, 

 20-45 X 6-9 [i, in all regions of the fructification; cystidia in- 

 crusted, cylindric, 25-30 X 4J^-5 &a, protruding up to 20 [l 

 beyond the basidia, confined to the hymenium; spores hyaline, 

 even, flattened on one side, 5 X 2% [i. 



Fructifications received in fragments 1-2 cm. long, 5-10 mm. 

 wide. 



On bark of Pinus austriaca (cult.). New York. October. 



In general aspect P. duplex suggests small fructifications of 

 P. gigantea but not curling away from the substratum at all. 

 The cystidia are smaller than those of P. gigantea and the latter 

 does not have gloeocystidia. 



Specimens examined: 

 New York : Shelter Island, W. G. Farlow, type. 



76. P. mutata (Peck) Bresadola in Bourdot & Galzin, Soc. 

 Myc. Fr. Bui. 28: 399. 1913. 



Corticium mutatum Peck, N. Y. State Mus. Rept. 43 : 67. 1890. 



Type: in N. Y. State Mus. Herb. 



Fructifications broadly effused, membranaceous, fleshy, thick, 

 separable when moistened, drying white to pinkish buff, some- 

 times centrally tuberculose or with raduloid teeth and occasion- 

 ally with radial folds, sometimes cracking in drying and showing 

 the white, fibriilose subiculum in the fissures, the margin white, 

 radially byssoid; in structure 300-1000 [x thick, composed of 

 loosely arranged, ascending, thin-walled, hyaline hyphae 3-4 y. 

 in diameter, occasionally nodose-septate; gloeocystidia pyriform, 

 15 X 7 (jl, more or less numerous, sometimes grown out into elon- 

 gated, flexuous form up to 100 X 4-5 [l, occurring as hyphal 

 ends or branches in the sybhymenium; cystidia incrusted or not 

 incrusted, 50-100 X 6-15 y., sometimes not protruding beyond 

 the basidia and sometimes so few present as to be found only 

 after examination of several sections; basidia 4-spored, with 

 short, thick, knob-like sterigmata; spores hyaline, even, cylindric, 

 8-16 X 3-4 (x. 



