yj Preface. 



With the introduction of characters due to local con- 

 ditions, a description ceases to be a specific diagnosis 

 in the proper sense, and is merely a description of a 

 certain state of a species occurring under a given set of 

 conditions. Such, however, is too frequently the nature 

 of so-called specific characters given in local Floras. 



A lengthy and laboured description suggests lack of 

 power to grip essentials on the part of the compiler, and 

 does not as a rule facilitate the recognition of the species 

 intended. 



The idea of this work is to give the essential characters 

 of each species as presented by pileus, gills, stem and 

 spores respectively. This, however, owing to the views 

 of some authors as to the predominant value of one 

 feature to the exclusion of others, has not always been 

 possible, For this reason the species of Britzelmayr are 

 not included, as his descriptions, even when aided by 

 what are presumably intended as figures, could not in 

 many instances be construed into an intelligible diagnosis. 



In Cooke and Que'let's Clavis Synoptica Hymeno- 

 mycetum Europaeorum (1878), 1943 species of Agarics 

 are recorded as European, and of these 939 are given 

 as British. The present work includes descriptions of 

 2750 European species, of which 1553 are British, a 

 number considerably in excess of that recorded for the 

 species of any other European country. 



The species indicated by brackets have not been re- 

 corded as British. 



G. M. 



KKW, June, 1902. 



