The North American species of Psathyrella.

1972]

PSATHYRELLA

125

inequilateral, color in KOH vinaceous-brown slowly becoming dull cocoa-color, in
Melzer's ochraceous-tawny to tawny or finally some redder, wall about 0.2, thick.
Basidia 4-spored, 15-18 pt long, clavate, hyaline. Pleurocystidia 26-52 x
10-17 a, utriform to broadly ventricose with rounded apex, wall thin, very pale
ochraceous-cinnamon to hyaline revived in KOH, smooth, content not distinctive,
(either in KOH or Melzer's). Cheilocystidia 9-16 tu wide, mostly clavate to saccate
or vesiculose, wall hyaline to faintly ochraceous in KOH, smooth, up to 0.4 [k thick
in some. Caulocystidia resembling the cheilocystidia or somewhat larger.
Pileus cuticle a layer of vesiculose cells several deep, the walls pale ochraceouscinnamon in KOH to nearly hyaline and bright yellow in Melzer's, smooth, thin
(about 0.5 jt). Hyphae of the context smooth, paler in color than cells of the
cuticle as revived in KOH. In mounts in Melzer's no tissue showing a distinctive
reaction other than in walls of cuticular cells. Clamps present.
Type locality. Near Pinckney, Michigan.
Habit and habitat. Gregarious on an old hardwood log, September.
Distribution. Known only from the type locality.
Observations. As dried the gills are the color of those of P. spadicea but the
cystidia distinguish between the two at once.
80. Psathyrella larga (Kauffman) A. H. Smith, comb. nov.
Psilocybe larga Kauffman, Agar. Mich. 279. 1918.
Illust. 1. c. pl. 57. P1. 39; Text Figs. 201-203.
Pileus 4-14 cm broad, ovoid to campanulate at first, finally expanded to plane
or with a low broad umbo; surface at first dotted with scattered small snow-white,
floccose superficial scales, soon denuded, often with only a white silky margin
when collected; surface smooth and moist, often cracking radially near the margin,
hygrophanous, bay-brown to ochraceous-brown and margin even when moist,
fading to whitish tan and becoming radiately rugulose. Context rather thin and
very fragile, white when dry, odor and taste not distinctive.
Lamellae adnate, rounded next to the stipe, rather broad, close, varying to
subdistant in age, white at first then pale fuscous, finally umber, edges minutely
white-fimbriate.
Stipe stout, 5-10 cm long, 5-15 mm thick, equal or tapering upward, soon
hollow, terete or compressed, rather firm, usually striate to sulcate, furfuraceous
but glabrescent, then shining white, cortex subcartilaginous.
Spores 7-9.5 x 4-5.5 a, smooth, apical pore distinct but minute, apex not truly
truncate, shape in face view broadly elliptic, in profile subelliptic to obscurely
inequilateral, color revived in KOH bister becoming near "mummy brown" to
finally dark chocolate-color, in Melzer's tawny to tawny-red, wall about 0.3 p
thick.
Basidia 4-spored, 26-34x 7-9 au, clavate, hyaline in KOH. Pleurocystidia
64-80 x 12-16 (-20) j, abundant, elongate-utriform above a narrowed pedicel, wall
thin, smooth and hyaline, cell content not distinctive in KOH or in Melzer's.
Cheilocystidia similar to pleurocystidia but often shorter. Caulocystidia similar
to pleurocystidia but often smaller, scattered to rare.
Pileus with a cuticle of vesiculose cells 2-4 deep, the walls thin and hyaline,
cell content not distinctive. Hyphae of the context nearly tawny when first
revived in KOH but fading, hyphae in region of subcutis minutely granularroughened to distinctly roughened with ochraceous-brown lines and patches of
deposit, in the region adjacent to the cuticle and including the bases of the