Vol. 12 

 232 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Fructifications long-effused, adnate, thin, tender, small pieces 

 separable, white, becoming light buff when old and in the her- 

 barium, somewhat granular, becoming cracked into polygonal 

 masses 1-2 mm. in diameter, the margin thinning out; in section 

 70-200 \k thick, not colored, composed of suberect, thin-walled, 

 branching hyphae about 3 [x in diameter, occasionally nodose- 

 septate, not incrusted, sometimes slightly brownish near the 

 substratum; no gloeocystidia; cystidia not incrusted, 3 pi in di- 

 ameter, tapering towards the apex, protruding 10-20 y., sometimes 

 very few and inconspicuous; spores hyaline, even, 4-6 X 2%- 



3 \L. 



Fructifications 2-20 cm. long, 1-2 cm. wide. 



On bark of fallen decaying branches on the ground, of Alnus, 

 Acer, Tilia, Populus, and other frondose species. Canada to 

 Alabama and westward to Washington. July to February. 

 Frequent. 



P. albula belongs near P. Sambuci on account of its white color, 

 somewhat granular hymenium, and minute cystidia which are not 

 incrusted and sometimes so few and inconspicuous that they may 

 possibly be overlooked, and the specimen referred to Corticium. 

 P. albula differs from P. Sambuci in not having the hyphae in- 

 crusted in a subhymenial zone and in having them sometimes 

 slightly brownish towards the substratum. 



Specimens examined: 

 / Exsiccati: Ellis, N. Am. Fungi, 409, under the name Corticium 



calceum. 

 Canada: J. Macoun, 5, type; Beechwood Cemetery, other locality 



not given, /. Macoun, 58; Ottawa, J". Macoun, 9. 

 Maine: Kittery Point, R. Thaxter & E. A. Burt. 

 New Hampshire: Chocorua, W. G. Farlow, D (in Mo. Bot. Gard. 



Herb., 56132). 

 Massachusetts: Sharon, A. P. D. Piguet, 137, comm. by Farlow 



Herb, (in Mo. Bot. Gard. Herb., 59628); Wayland, A. B. Sey- 

 mour, T 8 (in Mo. Bot. Gard. Herb., 19550). 

 New York: Albany, H. D. House, 3 gatherings (in N. Y. State 



Mus. Herb., and Mo. Bot. Gard. Herb., 57447, 59683, 59686); 



Ithaca, several collections by G. F. Atkinson, H. L. Jackson, 



C. 0. Smith, and Van Hook, comm. by G. F. Atkinson, 8028, 



