The North American species of Psathyrella.

1972]

PSATHYRELLA

419

Distribution. Wyoming.
Observations. This fungus has the appearance of P. incerta or P. coronata in
the field but possesses pleurocystidia and apparently a veil is lacking.
Psathyrella subg. Cystopsathyra Singer, Agar. Modern Taxon. 511. 1962.
Outer veil powdery, the cells mostly in the form of sphaerocysts which are soon
worn away leaving a more or less glabrous pileus.
Type. Psathyrella kellermanii (Peck) Singer.
Key to the Species of Subgenus Cystopsathyra
1. On soil (in green houses); spores 8-12 X 6-7 A. 397. P. kellermanii.
1. Not as above. 2
2. On horse dung. 396. P. sphaerocystis.
2. On soil. 402. P. floridana.
2. On hardwood logs. see 180. P. minutisperma also.
396. Psathyrella sphaerocystis Orton, Notes Roy. Bot. Gard. Edinburgh 26: 57.
1964.
Illust. Text Figs. 857-861.
Pileus 6-15 mm broad, obtusely conic when young, expanding to broadly conic
or convex, surface dry and granulose-squamulose, in age nearly glabrous, margin
fringed at first, color "wood brown" to "avellaneous" and developing a cinnamonbuff tone, when dried "cinnamon." Context very thin and fragile, buff-colored,
taste disagreeable, odor none.
Lamellae broad, subdistant, broadly adnate, dull cinnamon-buff becoming
"hair brown" (brownish gray), edges even.
Stipe 2-3.5(-4) cm long, up to 1 mm thick, more or less glabrescent in age,
pallid above, lower part dingy cinnamon-buff.
Spores 7-9x4.5-5.5 j, smooth, pore apical and distinct, the apex truncate,
shape in face view broadly ovate to elliptic, in profile obscurely inequilateral
varying to subelliptic, color in KOH dark coffee-brown becoming dark chocolate
color, in Melzer's bay-red to tawny-red, wall about 0.4 [ thick.
Basidia 4-spored, short-clavate, 15-22 x8-9 ~j, hyaline. Pleurocystidia 26 -38 8-12(-13) A, fusoid-ventricose, apex subacute to obtuse, wall thin, smooth
and hyaline, cell content not distinctive. Cheilocystidia similar to the pleurocystidia or neck almost lacking.
Gill trama vinaceous-cinnamon in KOH, fading on standing. Pileus trama
dark vinaceous-cinnamon and hyphae incrusted. Cuticle of pileus of vesiculose
cells yellowish in H20 and cinnamon to vinaceous-cinnamon in KOH, with pigment deposits in the angles. Clamps present.
Type locality. Scotland.
Habit and habitat. On horse dung, September.
Distribution. Idaho.
Observations. This species is truly a granulose Psathyrella, and its veil
represents the endpoint of cell disarticulation as this occurs in the genus.
397. Psathyrella kellermanii (Peck) Singer, Mycologia 51: 392. 1959.
Galera kellermanii Peck, Jour. Mycol. 12: 148. 1906.
Galerula kellermanii (Pk.) Murrill, N. Am. Fl. 10: 165. 1917.
Illust. Peck, 1. c., pl. 89.
Pileus 2-3 cm broad, obtuse expanding to plano-umbonate or nearly plane,