14 GENERA OF FUNGI 



study of the principal literature of the subject and the critical work of 

 recent mycologists, and the revisionists in particular, as well as upon some 

 forty years of mycological experience on the part of the authors. An 

 attempt is made here to account for all the genera of fungi, with the excep- 

 tion of a very large number of older and generally accepted synonyms. All 

 new genera published since the first edition are included so far as known 

 either as valid names, synonyms or dubia, but for the reasons given earlier, 

 some omissions are unavoidable. In some instances, names have been pro- 

 posed with the promise of future diagnosis, and in others, names adequately 

 published have completely dropped from sight in later treatments without 

 the slightest mention. In this connection the statement made by Fries in 

 1849 that "A single long-known and well-developed species correctly 

 observed through all its stages is of more value than a new genus" is in even 

 greater need of being emphasized now than it was in his day. A thorough 

 study of the older genera and species, most of which are still imperfectly 

 known, would contribute more to the advancement of mycology than the 

 continued increase of doubtful new ones. 



The adoption of well-established criteria for genera has necessarily led 

 to the rejection of a large number of genera proposed during the past two 

 decades. On the other hand a small number of genera are proposed on the 

 basis of criteria generally recognized, in order to render the Key more uni- 

 form and usable. 



Generic Types 



Mycological literature is cluttered with numerous genera and species 

 inaccurately or incompletely described, and in many cases not represented by 

 type or authentic specimens. Too often genera have been based upon scanty, 

 immature or worthless material that gave scope to the widest range of inter- 

 pretation. One of the greatest obstacles to the progress of mycology is this 

 mass of names variously applied and interpreted at different times by 

 mycologists. These must be either attached to definitely known species and 

 to particular specimens available for complete description and positive identi- 

 fication, or permanently discarded. Many of these old generic names have 

 already become more or less definitely applied and established by general 

 usage, and they may be fixed in their current application by the selection of 

 well-known species as types. The present use of names has been evolved 

 by gradual changes at the hands of subsequent mycologists, instead of being 

 definitely fixed on the basis of an exact determination of the type of the 

 original author of the name. Hence, the citation of the original author of 

 an old name may have little to do with its present application. In fact, 

 authors themselves have sometimes changed their descriptions, as well as the 

 types of their genera. 



In order that generic names may be as exact as possible in their appli- 

 cation, it is now generally admitted by taxonomists that they should be fixed 

 by assigning to each a type species, and the recent International Botanical 



