THE PSEUDORHIZA OF COPRINUS MACRORHIZUS 355 



spored is indicated by Rea ^ who has described the basidia of M. 

 galericulata as " generally with 2-sterigmata only " and by Bauch ^ 

 who, in his hst of the Hymenomycetes having two-spored forms, 

 remarks that the fruit-bodies of M. galericulata found at Rostock 

 were " meist zweisporig." Moreover, Rea has informed me that 

 he has observed fruit-bodies of M. galericulata with quadrisporous 

 basidia. It may be that, as Bauch ^ found in Camarophyllu^ 

 virgineus (one of the Hygrophoraceae), the two-spored fruit-bodies 

 of M. galericulata are haploid, while the four-spored are diploid. 

 Another possibility is that both forms are diploid, but that two 

 nuclei migrate into each spore of the two-spored form, while 

 only one nucleus migrates into each spore of the four-spored 

 form. The problem here suggested can be solved only by precise 

 investigation . 



Coprinus macrorhizus. — This species has been confounded with 

 Coprinus lagopus (= C. cinereus = C. fimetarius "*), and in Massee's 

 British Fungus-Flora it is called Coprinus fimetarius, var. macro- 

 rhizus. A comparative study of the Coprini has taught me that 

 Coprinus lagopus and C. macrorhizus are independent species. This 

 conclusion is based not merely on studies in the field but also on a 

 comparison of pure cultures. The following are some of the points 

 by which the two species may be distinguished. 



(1) Exterior of thepileus. The pileus of C. macrorhizus (Fig. 177) 

 is rounded at the top, pale, and brownish-grey, the brown being 

 particularly marked at the apex. The pileus of C. lagopus (Fig. 133, 

 Vol. Ill, p. 305) is more conical, and ashy-grey except at the 

 very apex which is brown. The floccose scale-hairs on the surface 

 of the pileus of C. macrorhizus are more matted than those of 

 C. lagopus. 



(2) Breadth of gills. The gills of C. macrorhizus are distinctly 

 broader than those of C. lagopus. The more conical form of the 



^ Carleton Rea, British Basidiomycetae, Cambridge, 1922, p. 384. 



^ R. Bauch, " Untersuchungen iiber zweisporige Hymenomyceten. I. Haploide 

 Parthenogenesis bei Camarophyllus virgineus," Zeitschrift f. Botanik, Bd. XVIII, 

 1925-1926, p. 344. 



3 Ibid., pp. 354-382. 



^ Cf. these Researches : Vol. Ill, 1924, pp. 301-303 ; and Vol. IV, 1931, pp. 191- 

 193. 



