PREFACE. 



/RESERVATIONS extending over a period of twenty- 

 ^-^ five years, made at Fungus Forays and kindred 

 meetings where Mycologists assemble together, has led 

 to the conviction that familiarity with the Fungi and 

 literature pertaining thereto, of one country only, leads 

 to a false impression as to the significance of the term 

 ' species.' 



It conveys the idea that species are much more 

 sharply defined than proves to be the case, when the 

 entire Fungus Flora of Europe is included. 



In all large genera common to European countries, 

 the continental species can be sandwiched between 

 British species. Even in large genera there are as a 

 rule not more than eight or ten primary differentiating 

 specific characters present, and it is the constant correla- 

 tion of two or three of those primary characters that 

 constitute a species, as understood at the present day. 



If two British species are characterised respectively 

 by the marks 1, 2, and 3, 4, then we find that two 

 continental species belonging to the same genus will be 

 indicated by the characters 1, 3, and 2, 4, respectively. 



Primary specific characters should include only those 

 features that are constant, and not materially modified 

 by geographical or exceptional local conditions as to 

 environment, etc., and such alone should constitute a 

 specific diagnosis. Trivial or local characteristics should 

 follow the essential diagnosis as a rider. 



