1925] 



BURT THE THELEPHORACEAE OF NORTH AMERICA. XIV 221 



noid; in section 150-300 ^ thick, not colored, 2-layered, with the 

 layer next to the substratum composed of very loosely arranged, 

 nodose-septate, hyaline hyphae 3-4 ^ in diameter and with the 

 hymenial layer about 50 y. thick, compact; no gloeocystidia; 

 cystidia numerous, tapering, rough or granule-incrusted near the 

 tips, 4-6 (j. in diameter, protruding up to 40 y. beyond the basidia; 

 spores hyaline, even, 3-4 X 2-2 J/ \l, copious. 



Fructifications 1-4 cm. in diameter. 



On bark of fallen limbs of Populus and A Inus. New Hampshire, 

 New York, Alabama, and Oregon. October and November. Rare. 



P. arachnoidea has the aspect of Corticium arachnoideum but 

 is a Peniophora. The hyphae and their arrangement are like 

 those of P. cremea. The microscopic characters are so similar to 

 those of Coniophora byssoidea that the gatherings from northern 

 localities may possibly be white forms of the latter which I have 

 erroneously included under P. arachnoidea. 



Specimens examined: 

 New Hampshire: Hanover, on Populus, G. R. Lyman, 27 (in 



N. Y. Bot. Gard. Herb., Mo. Bot. Gard. Herb., 61589, and 



Burt Herb.). 

 New York: Ithaca, G. F. Atkinson, 2589, formerly referred by 



me to C. byssoidea; Karner, on Populus, H. D. House (in N. Y. 



State Mus. Herb., and Mo. Bot. Gard. Herb., 54376). 

 Alabama: Auburn, on Alnus, F. S. Earle, 97, type, comm. by 



N. Y. Bot. Gard. Herb.; Montgomery County, R. P. Burke, 



867 (in Mo. Bot. Gard. Herb., 57234). 

 British Columbia: Salmo, J. R. Weir, 472, 480 (in Mo. Bot. Gard. 



Herb., 63357, 63387). 

 Oregon: White Pine, on hymenium of Thelephora terrestris, J. R. 



Weir, 620 (in Mo. Bot. Gard. Herb., 13999). 



4. P. inconspicua (B. & C.) Massee, Linn. Soc. Bot. Jour. 25: 

 149. pi. 47, f. 14- 1889; Sacc. Syll. Fung. 21 : 410. 1912. 



Corticium inconspicuum Berkeley & Curtis, Linn. Soc. Bot. 

 Jour. 10: 336. 1868; Sacc. Syll. Fung. 6: 615. 1888. 



Type: in Kew Herb, and Curtis Herb. 



Fructifications effused, thin, small, orbicular, gregarious, be- 

 coming confluent, membranaceous, small pieces separable, white 



