THE PSEUDORHIZA OF COPRINUS MACRORHIZUS 357 



(5) Stipe. The aerial part of the stipe of C. macrorhizus is usually 

 stouter and firmer than that of C. lagopus {cf. Figs. 180 and 185, 

 pp. 360 and 367, with Fig. 133, Vol. Ill, p. 305). The stipe of 

 C. macrorhizus frequently ends below in a long conspicuous sub- 

 terranean " rooting 



base " or pseudo- 

 rhiza. In C. lagopus 

 such an organ is 

 usually absent. 



( 6 ) Substratum. 

 C. lagopus is ex- 

 tremely common on 

 horse-dung balls, as 

 is shown by the fact 

 that fresh balls col- 

 lected at Vancouver 

 (British Columbia), 

 Edmonton (Alberta), 

 Shellbrook (Saskat- 

 chewan), Winnipeg 

 (Manitoba), and in 

 three different places 

 near Birmingham, 

 England, all yielded 

 fruit-bodies of this 

 species.^ C. macro- 

 rhizus, on the other 

 hand, very rarely 

 comes up on isolated 

 dung-balls but is ex- 

 tremely frequent on 



large masses of horse dung, such as are represented by manure 

 piles, hot-beds, and the like. C. macrorhizus seems to be specially 

 adapted to flourish in dung well mixed with straw and heated by 

 the fermentation process. 



^ W. F. Hanna, " The Problem of Sex in Coprinus lagopus," Annals of Botany, 

 Vol. XXXIX, 1925, pp. 433-434. 



Fig. 178. — Coprinus macrorhizus. Mature fruit-bodies 

 shedding spores, growing on stable manure. The 

 one on the extreme right has its pseudorhiza in 

 view. Photographed at Birmingham, England. 

 Natural size. 



