1926] 



BURT THELEPHORACEAE OF NORTH AMERICA. XV 209 



vestiens and C. jamaicense but a comparable type of hyphal dif- 

 ferentiation. The great distance between the two stations leads 

 me to suspect that C. Atkinsonii is more frequent than indicated 

 by the collections in which the distinctive branching was ob- 

 served. 



Specimens examined : 

 New York: Altamont, E. A. Burt; Ithaca, G. F. Atkinson, 2558, 



type. 

 Louisiana: A. B. Langlois, 246, comm. by U. S. Dept. Agr. Herb. 



24. C. subnullum Burt, n. sp. 

 Type: in Mo. Bot. Gard. Herb. 



Fructifications effused, closely adnate, very thin, cartridge- 

 buff to olive-buff in the herbarium, hypochnoid, not forming a 

 continuous hymenium but with the basidia in more or less con- 

 nected tufts of about 3-5 to the mm., farinaceous, the margin 

 similar; in section 30-45 [l thick, not colored, composed of loosely 

 arranged, hyaline hyphae 2-2 J^ y. in diameter, thin- walled, not 

 incrusted, not nodose-septate; no gloeocystidia; spores hyaline, 

 even, globose, 2J/ \i in diameter, borne 4 to a basidium. 



Fructifications 3-7 cm. long, 2-3 cm. wide. 



On bark of decaying logs of Populus sp. British Columbia. 

 July. 



When C. subnullum becomes better known from additional col- 

 lections, it may become necessary to transfer it to another genus, 

 but the present gathering favors the view that it is a Corticium 

 somewhat lacking basidia so that the hymenium becomes discon- 

 tinuous. This character, occurrence on poplar bark, small 

 spores, and general aspect of an olive-buff Hyphomycete are good 

 distinctive characters. 



Specimens examined : 

 British Columbia: Sidney, J. Macoun, 80, type (in Mo. Bot. 



Gard. Herb., 63776). 



25. C. crustulinum Burt, n. sp. 

 Type: in Mo. Bot. Gard. Herb. 



Fructifications effused, thin, tender, separable, with the sub- 

 stance whitish, dry, soft anq cottony, and the hymenium warm 



/ 



H 



