PEEFACE. 



It is now twenty-one years since the last complete Biitisli 

 Mycological Flora was publislied.— Cooke's "Handbook of 

 British TTingi " — the number of species therein described 

 being 2810, whereas the species now number 4895, and are 

 distributed as follows : — Basidiomycetes, 1980 ; Ascomycetes, 

 12V5 ; Sphaeropsideae, 685 ; Hyphomyoetes, 680 ; Uredineae 

 and Ustilagineae, 230 ; Phycomycetes, 145. 



In the Basidiomycetes, with which the present volume 

 deals, the specific characters are mainly derived from 

 morphological features, with the additional physiological 

 characters furnished by colour, smell, and taste, and are 

 consequently not so readily determined as in some of the 

 other groups, where the size of the spores in microns is by 

 many considered, along with a knowledge of the host, to be 

 all that is required for the discrimination of species ; and 

 when we bear in mind that no two persons ever succeed in 

 making the same measurements of the spores of a given 

 species, else the spores are very variable in the same species, 

 the great increase in number of microscopic fungi is not to 

 be wondered at. 



There are no better marked species to be met with anywhere 

 in the vegetable kingdom than in the Agaricinae, but the 

 majority of species vary within certain limits. I have 



