[Vol. 12 

 214 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



seems desirable by color of hymenium, adnation to substratum, 

 and incrustation of cystidia or of hyphae, into minor groups of so 

 few species that the characters of the component species of any 

 group within which a species seems to belong, may all be con- 

 sidered in determining the probable species of the specimen in 

 course of identification. An appalling amount of time and 

 labor has been required for the accumulation from sectional prep- 

 arations of the structural characters of the individual specimens 

 of species of Peniophora listed in this work. The older descrip- 

 tions of resupinate Hymenomycetes were based on so few definite 

 characters that a specimen in hand might seem to be referable 

 equally well to more than one published species, or that several 

 specimens in hand and certainly different specifically might all 

 seem referable to one species, judging from its published de- 

 scription. However, by the addition of the knowledge of the 

 definite features of structure characteristic of species, deter- 

 mining additional characters have been found for so many species 

 that the specific taxonomy of the large genus Peniophora in 

 North America becomes practicable. In the use of this work 

 sectional preparations of fertile specimens are necessary. 



Of the 120 species of Peniophora described herein, 36 occur in 

 Europe as well as in North America and 11 others have been 

 already recognized as North American species. The remaining 

 73 species are unlike those which the writer has been able to 

 recognize among the known species from other regions of the 

 world and have therefore to be described as new. It is quite 

 probable that nearly all of these 73 species will bear the test of 

 study by foreign mycologists and be demonstrated eventually to 

 be really new, for most of them are of local occurrence, known 

 from a single collection and distributed with surprising uniformity 

 over the great area of North America which has in its different 

 regions such great differences in temperature, moisture, altitude, 

 and composition of its forests that the conditions are ideal for 

 the origin and survival of species of merely local distribution. 

 This is in accord with the fact that 9 of our new species occur in 

 more than one state and that others occur as follows: — 7 from 

 Louisiana; 4 each from New York, British Columbia, Washing- 

 ton, Mexico, and Jamaica; 3 each from Vermont, Idaho, Oregon, 



