[Vol. 13 

 174 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Fructifications waxy, crustaceous or floccose, fleshy, cartilagin- 

 ous, coriaceous or membranaceous, always resupinate, effused; 

 hymenium even, or somewhat tubercular in a few species ; basidia 

 simple with 2-8 sterigmata, usually 4, the sterigmata not greatly 

 thickened ; basidiospores white, even green in C. atrovirens; sub- 

 stance variously differentiated but not containing colored, stellate 

 organs. Distinguished from Peniophora by not having cystidia. 



The species described as belonging in Corticium upon publica- 

 tion of the genus are Corticium polygonium, C. laeve, C. roseum, 

 C. Sambuci, C. cinereum, and C. aurantium, in the order given, 

 no one of which was designated as the type species. C. Sambuci 

 and C. cinereum are now included in Peniophora and C. aurantium 

 in Aleurodiscus. 



Von Hohnel and Litschauer and Bourdot and Galzin have 

 segregated under Gloeocystidium Karsten all species of Corticium 

 which have gloeocystidia. I have not followed them in this, 

 because I regard gloeocystidia as but one of the several differ- 

 entiations of tissue which afford helpful distinctive characters 

 for recognition of the species of this genus. In fact, I feel that 

 closer observation of the tissues and structure of the fructification 

 and accurate record of such structure should give important, and 

 often decisive, characters of all the species. My own study has 

 already gone so far in this direction that I attach but slight regard 

 to a specific determination which is based merely upon obvious 

 external characters and the substratum upon which growing. A 

 sufficient objection to Gloeocystidium for the species which have 

 gloeocystidia is that one of the two species upon which Karsten 

 founded the genus is Peniophora guttulifera, a true Peniophora 

 with no gloeocystidia whatever, and the other is Odontia sudans. 



Asterostromella as a genus to include Corticium investiens, a 

 species with helpful hyphal differentiation, is antedated by 

 Karsten's Vararia, having C. investiens as its type species. 



What was shown in the preceding part about the distribution of 

 our species of Peniophora is true also for Corticium. Of the 107 

 species of Corticium herein presented, 46 are described as new 

 species. The color of the exterior of the fructification and of its 

 internal substance and the presence of tissues of somewhat un- 

 usual form have afforded a basis for the arrangement of our 



