240 THE AGARICACEAE OF MICHIGAN 



spores of P. augusta are 12-14 x 6-7 micr., per Kicken ; of P. perrara, 

 8-10x5 micr., per Bresadola. P. silvatica Fr. differs in the smaller 

 size, the simple annulus and differently colored pileus. P. subru- 

 fescens sometimes appears in hot-house beds and has been reduced to 

 cultivation, where its characters seem to be somewhat changed, so 

 that Peck has made a lengthy comparison between it and P. cam- 

 pestris, to which the wild form has no close resemblance. 



Section II. Univelares. Annulus simple, not with thick floccose- 

 patches on under side. 



229. Psalliota campestris Fr. (Edible) 



Syst. Myc, 1821. 



Illustrations: (Selected, very numerous.) 

 Fries, Sverig. atl. o. gift. Swamp., PL 5. 

 Cooke, 111., PL 52G. 



Gillet, Champignons de France, No. 573 (As Pratella). 

 Michael, Fiihrer f. Pilzfreunde, Vol. I, No. GO. 

 Bresadola, I. Fung. mang. e. velenos, PL 53. 

 Marshall, The Mushroom Book, PL 23, op. 71 and PL 24, op. 



75, 1905. 

 Gibson, Our Edible Toadstools and Mushrooms, PL 5, p. 



83 and PL 6, p. SO. 

 Murrill, Mycologia, Vol. I, PL 3, Fig. 1. 

 Hard, Mushrooms, Fig. 248 and 249, p. 307, 1908. 

 Atkinson, Mushrooms, Figs. 1-8, pp. 2-8, 1900. 

 Atkinson, Bot. Gaz., Vol. 43, p. 264 et. al., PL 7, 8, 9, 10, 11 



and 12 (showing all stages of development). 



• 



PILEUS 4-7 cm. broad (occasionally larger, especially when 

 cultivated), at first flattened hemispherical then convex-expanded 

 or nearly plane, firm, even, glabrous or at length minutely floccose- 

 silky or delicately fibrillose-scaly, dry, white (scaly forms are 

 brownish, etc.), the margin extending beyond gills, edge often 

 fringed when fresh by the tearing of the partial veil. FLESH 

 thick, white, not changing when bruised. GILLS free but not re- 

 mote, rounded behind, ventricose, not broad, close, almost from 

 the very first delicate pink, then deep -flesh color, finally purplish- 

 brown to blackish, edge even. STEM 5-7 cm. long, thick, usually 

 subequal or tapering downward, rarely subbulbous, solid-stuffed, 



