1916] 



BUKT THELEPHOEACEAE OF NORTH AMERICA VI 205 



subgenera of Corticium. As several species of Corticium 

 were still included in Hypochnus, Fries liad good reason for 

 regarding Hypochnus in liis sense as closely related to Cor- 

 ticium. Karsten's emendation of Hypochnus a few years 

 later was logical, and in sympathy with the work of Fries, 

 for it retained this name for the greatest number of co- 

 generic species both originally published in the genus and 

 retained in the final work of Fries. These species are fur- 

 thermore the only species for which the generic name Hy- 

 pochnus can be retained, for the other species of the sub- 

 genus in Fries' ' Hymenomycetes Europeae' revert to Cor- 

 ticium under modern study. 



Hypochnus, as presented in Saccardo's 'Sylloge Fungo- 

 rum,' is an aggregation of species of several genera and 

 includes also the tropical lichens which Fries excluded from 

 the genus in 1874. Hypochnus as given in Engler & Prantl's 

 'Die Natiirlichen Pflanzenf amilien, ' is the presentation of a 

 purely academic scheme of Schroeter's as to how the lower 

 Hymenomycetes ought to be classified to have a family 

 Hypochnacei, but the fungi do not fall in with the scheme. 

 They cannot be separated from Corticium and Peniophora. 

 Von Hohnel and P. Sydow have pointed out ^ that Hypochnus 

 in the sense of Schroeter must be abandoned as a genus and 

 its species take their proper places in other genera. It is to 

 be regretted that Saccardo's 'Sylloge Fungorum' and Engler 

 & Prantl's 'Die Natiirlichen Pflanzenf amilien' give a false 

 lead with regard to Hypochnus, for these works are the main 

 reliance of plant pathologists in the matter of genera. 



Key to the Species 



Spores distinctly colored as seen with the microscope 1 



Spores so pale yellowish or hyaline as to appear hyaline or nearly 



so under the microscope 16 



1. Fructification "ferruginous," i. e., Sudan-brown,* Brussels-brown, and 

 hazel of Eidgway; spores concolorous with the fructification, but wax- 

 yellow under the microscope 2 



*Ann. Myc. 4:551. 1906. See also von Hohnel & Litschauer, Ann. Myc. 

 4:288. 1906. 



*The technical color terms used in this work are those of Eidgway, Color 

 Standards and Nomenclature. Washington, D. C, 1912. 



