302 RESEARCHES ON FUNGI 



macrorhizus Pers.) is quite distinct from C. lagojms, for it differs 

 from the latter in its well-developed pseudorhiza, its whiter and less 

 fragile stipe, the more rounded and paler apex of its pileus, its 

 broader and ventricose gills, its smaller and more oval spores, and 

 particularly (a point which may be made out in the field with the 

 naked eye or a pocket lens) in the fact that its cystidia, like those 

 of C. atramentarius, bridge the interlamellar spaces and interlock 

 the gills during the discharge of the spores (Fig. 128, p. 296). In 

 both England and central Canada, on fresh horse-dung balls kept in 

 covered crystallising dishes in the laboratory, C. lagojms almost 

 always appears, but very rarely C. macrorhizus. C. macrorhizus 

 most commonly occurs on warm straw-manure piles outside stables 

 (Fig. 128). I have cultivated C. lagopus and C. macrorhizus on 

 sterilised horse dung side by side in the laboratory and found that 

 the two species are just as distinct from one another in cultures as 

 they are under natural conditions. There can be no doubt that 

 Rea ^ was fully justified in raising C. 7nacrorhizus to specific rank. 

 A good illustration of C. macrorhizus is to be found in Cooke's 

 Illustrations of British Fungi, Plate 670 ; and a series of photo- 

 graphs and sketches of this fungus will be reproduced in Volume IV 

 of this work. 



The name Coprinus fimetarius seems to have been used in the 

 past for two or more species resembling one another in having loose 

 white fugacious fiocci on the pileus and dense black spores. Some- 

 times the name has been applied to C. lagojms and sometimes to 

 C. macrorhizus.^ Since the specific name fimetarius has been used in 

 such a confused manner, we are perhaps justified in following Rea's 

 example and eliminating it altogether. Another name commonly 

 found in the literature is C. cinereus. I am inclined to believe that 

 C. cinereus has been used for a fungus which is identical with my 

 C. lagopus. 



From the above discussion it will be seen that Coprinus macro- 

 rhizus and C. lagopus are two distinct species, and that the names 



^ Carleton Rea, British Basidiomycetae, Cambridge, 1922, p. 503. 



2 The fungus illustrated by C. H. Kauffman in Plate XXXVIII of his 

 The Agaricaceae of Michigan (Lansing, U.S.A., 1918) as C. fimetarius is certainly 

 C. macrorhizus. 



