1925] 



BURT THE THELEPHORACEAE OF NORTH AMERICA. XIV 311 



Corticium aurantiacum Bresadola, Fungi Trid. 2: 37. pi. 144, 

 f. 2. 1892; Sacc. Syll. Fung. 11: 126. 1895. Kneiffia auran- 

 tiaca Bresadola, Ann. Myc. 1: 103. 1903. Gloeopeniophora 

 aurantiaca (Bres.) v. Hohnel & Litschauer, K. Akad. Wiss. Wien 

 Sitzungsber. 117: 1094. 1908. 



Type: probably in Bresadola Herb.; authentic specimen in 

 Burt Herb. 



Fructifications effused, beginning as small, convex outgrowths 

 at lenticels of the bark, spreading so as to form circular patches 

 which become confluent, adnate, bright orange-pink to orange- 

 chrome, fading in the herbarium to light pinkish cinnamon and 

 light buff, the margin white at first, radiating; in section not 

 colored, 150-250 fx thick, with the hyphae densely and longi- 

 tudinally arranged in a rather broad layer next to the substratum 

 except at the points of emergence from the lenticels, hyaline, 

 thin-walled, 3-4 [x in diameter; gloeocystidia 30-60 X 6-9 (x, 

 abundant in the convex portions; cystidia rough- walled, pointed, 

 up to 45 X 8 (x, sometimes protruding 30 jx beyond the basidia, 

 more often wholly immersed and 30 X 4-5 [*,; basidia large, 

 60 X 10-12 [l, often protruding beyond the immature basidia 

 when fruiting and bearing 4 sterigmata; spores hyaline, even, 

 12-16 X 6-12 (x. 



Fructifications 1-5 mm. in diameter at first, then laterally 

 confluent over areas 1-10 cm. long, 3^-2 cm. broad. 



On dead Alnus of various species. Labrador to North Caro- 

 lina, westward to northern United States and Canada to British 

 Columbia and Oregon, and in Europe. August to November. 

 Common. 



P. aurantiaca is easily recognized by its occurrence on dead 

 twigs of alder, in bright incarnate or orange-red fructifications 

 with large spores up to 15 X 10 (x. These spores are usually 

 borne copiously and show well in crushed preparations. To 

 demonstrate the gloeocystidia and cystidia it is necessary to 

 examine sections cut through the convex or papilliform points of 

 origin of the fructifications. Sometimes examination of many 

 sections is necessary for demonstration of the cystidia. Failure 

 to cut the sections from places above stated led me to refer 

 gatherings of this species to Corticium laetum for some of my cor- 



