154 Journal of the Mitchell Society [February 



that elongated or irregular groups are produced which may be a cm. 

 or more long and broad. When two plants meet and fuse a low ridge 

 is left on the hymenium. This plant is easily distinguished from the 

 other species of the genus here treated by the saucer-shaped form 

 and pliable, leathery texture when wet. 



3937. On bark of Ulmus near upper end of Scott's Hole, January 11, 1920. Photo. 

 Upper district. Bark of white oak. Curtis (as Corticium). 



2. Aleurodiscus candidus (Schw.) Burt. 

 Stereum carididum Schw. 



Plates 16 and 30 



A. small, entirely resupinate plant, growing on the bark of trees 

 and forming hard, crustaceous, chalk-white patches of irregular shape 

 and definite outline, usually under 2 cm. in diameter vith the margin 

 free so as to show its imder side which is blackish. Surface smooth, 

 minutely pulverulent under a lens, showing irregularities of the bark 

 over which it is spread. Flesh thick for so small a plant, about 0.5- 

 1 mm. thick, white or pale creamy, quite hard and brittle. Under a 

 lens the flesh shows a rather faint stratification with as many as 5 or 

 6 layers, each probably representing a period of fruiting, but the 

 time required to form each layer is not yet known. 



Spores white, subspherical to short-oval, minutely papillate, 

 12.5-16.7 X 16.6-22^1, most about 15 X 20A[i. Basidia large, club- 

 shaped, ll-14[x thick, with four very long sterigmata. Mixed with 

 the basidia are delicate, dense, hyphal paraphyses branched like a 

 bush above and much encrusted with granular crystals. 



The plant is very common in Chapel Hill on bark of post oak and 

 white oak, and is very easily recognized by its color, habit and place 

 of growth. Burt describes the spores as smooth, but suggests that 

 they may prove to be minutely rough walled. We find them min- 

 utely papillate. 



1377a. On bark of post oak trees, Movember 28, 1913. 

 1517. On bark of a post oak tree, December 14, 1914. 

 3827. On Hving post oak, December 6, 1919. 

 Salem. Schweinitz. 

 Low and middle districts, bark of trees. Curtis. 



