Preface 



Since Fries* treatment of Hygrophorus in Epicrisis Systematic 

 Mycologici (pp. 320-333) in 1838, there has been less confusion over 



species concepts in this genus than in most other genera of agarics. 

 This situation is due in part at least to the fact that field characters are 

 often critically diagnostic, and the differences between species are of- 

 ten striking. 



In North America, once a reasonable sample of the Hygrophorus 

 flora had been studied, it was found that most of the apparent confu- 

 sion here was caused by our attempt to "force" American Hygrophorus 

 populations into previously described species where they did not be- 

 long. True, there are confusing situations in this genus just as in any 

 other sizable genus of plants, but the various complexes, for instance, 

 do not approach in complexity those which Smith and Singer : have 

 encountered among the species of Galerina. 



The point of greatest difference between various investigators 

 hinges on what constitutes a discontinuity of generic magnitude. Al- 

 though we held a conservative point of view in our early work, we 

 have given serious consideration since then to the recognition of the 

 genera as Singer ( 1951 ) has outlined them. In fact at one time we were 

 almost ready to accept them. We finally returned to our original point 

 of view because we felt that those erecting new genera were simpK 

 doing it on the basis of single outstanding characters of odd species, 

 i.e.. Hygroaster, Neohygrophorus, and Hwnidicutis. There is better 

 evidence for recognizing Hygrotrama as a genus, but we believe this 

 group connects too clearly with the series Hygrocybe to justify generic 

 separation. On last analysis, however, this matter will probably con- 

 tinue to remain one of opinion, as it has in the past. Certainly each in- 

 vestigator may exercise his right of opinion, based on the material he 

 has seen. One point, however, which we would like to make, is that it 

 is to us more realistic to try to arrange the species of Hygrophorus in a 

 natural classification within a large genus than to distribute them 

 among a number of genera, and thus create the impression of a degree 

 of discontinuity which we believe does not actually exist. 



Unpublished studies. 



