COPRINUS LAGOPUS 303 



C. fimetarius and C. cinerevs have been discarded on account of 

 their being in all probability nothing but synonyms. 



Description of Coprinus lagopus. — Since C. lagopus occurs so 

 commonly in both Europe and Canada on fresh horse-dung balls 

 confined in crystallising dishes in laboratory cultures, and since 

 C. lagopus has been proved by Miss Mounce ^ to be heterothallic and 

 may be used again for the investigation of sex problems, and since 

 there has been, and still is, so much confusion in systematic works 

 in respect to C. lagopus and its allies, I shall here give as careful 

 a description of the species as I can with a view to making its 

 identification less difficult to future workers : — 



Fruit-bodies varying greatly in size from minute dwarfs with 

 stipes 1-10 mm. high and expanded pilei 0-75-3 mm. in diameter 

 occurring on old horse-dung balls in fields (Fig. 138, A and B, 

 p. 316) to very large specimens with stipes 130-185 mm. high and 

 expanded pilei 25-40 mm. in diameter occurring in pure cultures in 

 the laboratory and sometimes under natural conditions in the open 

 (Figs. 133 and 134 ; also Vol. II, Figs. 20 and 21, pp. 71 and 72). 

 Fruit-bodies occurring spontaneously on horse-dung balls confined 

 in large crystallising dishes in the laboratory (Fig. 130, p. 300) often 

 with stipes 25-120 mm. high and expanded pilei 5-25 mm. in 

 diameter. Dwarf fruit-bodies of this species were regarded by 

 Massee as belonging to Coprinus radiatus ; but, smce the mycelium 

 produced from the spores of a dwarf give rise in pure cultures to 

 very large fruit-bodies of C. lagopus, the separation of the dwarfs 

 as a distinct species has no real justification.^ 



Pileus varying greatly in size, before expansion 0-5-20 mm. high 

 (often about 6-10 mm. high), and after expansion 1-40 mm. wide 

 (often 12-20 mm. wide) ; at first cylindric-oval and smooth under 

 the down, then campanulate with a somewhat pointed apex and 

 becoming radially grooved owing to the partial cleavage of each 

 long gill down its median plane into two halves, then flattened, 

 radially sulcate up to the small disc, and splitting into a few rays 



1 I. Mounce, " Homothallism and Heterothallism in the Genus Coprinus," Trans. 

 Brit. Myc. Soc, vol. vii, 1922, pp. 256-269. 



2 Vide " The Dwarf Fruit-bodies of Coprinus lagopus,'' these Researches, vol. ii, 

 1922, pp. 82-88. 



