274 THE AGARICACEAE OF MICHIGAN 



This section approaches Stropharia ; it was raised to generic rank 

 by W. G. Smith under the name Deconica. The veil, although 

 usually very evanescent, may at times leave a slight annular mark 

 on the stem so as to simulate Stropharia, and hence the species must 

 be carefully compared with species of that genus. 



263. Psilocybe merdaria Fr. 



Syst. Myc, 1821 (as Stropharia in Hym. Europ.). 



Illustrations: Fries, Icones, PL 130, Fig. 3 (as Stropharia). 

 Cooke, 111., PL 537 (?) (as Stropharia). 

 Gillet, Champignons de France, No. 649 (as Stropharia). 

 Ricken, Blatterpilze, PL 66, Fig. 1. 



PILELTS 1-3 cm. broad, campanulate-keinispherical, finally plane, 

 livid-brownish to livid-yellow, obtusely subumbonate, slightly darker 

 on umbo, glabrous, even, subviscid, at first with slight Hecks on the 

 margin. FLESH pallid, thin. GILLS broadly adnate to triangu- 

 lar-subdecurrent, brood, subdistaiit, yellowish at first, then pow- 

 dered by purple-brown spores, at length dark brown. STEM 2-4 

 cm. long, 1-3 mm. thick, equal, even or slightly ridged at apex by 

 decurrent gills, delicately flocculose-fibrillose, glabresceut, pale yel- 

 lowish, stuffed then hollow, often with slight annular remnants or 

 fibrils. SPOKES large, 11-17x7-8 micr., elliptical, smooth, pur- 

 plish-brown under the microscope. CYSTIDIA none. ODOR mild. 



On horse dung along with Stropharia stcrcoraria. Ann Arbor. 

 May-June. Infrequent. 



Not to be confused with Xaucoria semiorbicularis, A. pediades 

 and A. platysperma, the spores of which are smaller and lack the 

 purple tinge. It is said to differ from P. coprinophila by the grayish 

 young gills of the latter. I have followed Karsten and Britzelmayr 

 (quoted by Sacc.) in referring this plant with large spores under 

 P. merdaria. Other authors differ widely and it is clear that several 

 species are either confused -or that the plant needs segregation. 

 Cooke, in the Illustrations, gives the size 8x5 micr. ; W. G. Smith. 

 9x6 micr. ; Ricken, 12-13 x 7-9 micr. Ricken says "the purplish 

 color of the spores disappears in dried specimens,'' hence the study 

 of exsicatti is of little value. 



