The North American species of Psathyrella.

1972]

PSATHYRELLA

273

Lamellae close, broad, ascending-adnate, seceding, fuscous in young and old
specimens alike, margins conspicuously white crenulate.
Stipe 4-5 cm long, 2-3 mm thick, equal, fragile, translucent-whitish becoming
brownish in drying, naked; no veil present.
Spores 15-20(-21) x7-9x8-10 /, smooth, germ pore indistinct on mature
spores and often oblique as seen in profile view, apex of spore not truncate, shape
in face view oblong to elliptic, in profile subelliptic to obscurely inequilateral,
color in KOH blackish brown, in Melzer's bay-brown, wall about 0.5 /t thick.
Basidia 4-spored, clavate, hyaline, 23-32 x 10-15 /. Brachybasidioles present.
Pleurocystidia not found. Cheilocystidia fusoid-ventricose, 28-50 x 10-30 /, varying to subelliptic, hyaline in KOH or walls weakly ochraceous and up to 0.3 -0.4 ji thick at times, smooth, cell content not distinctive.
Gill trama regular, hyphal walls yellowish brown, some incrusting yellowbrown pigment present. Pileus trama yellow-brown from incrusting amorphous
patches of pigment, cuticle of pileus of inflated cells 2-3 deep, weakly ochraceoustawny to hyaline in KOH, with pigmented wall thickenings in the angles at least
on basal cells, rusty brown flexuous thick-walled setae 80-200 x 4-7 / originating
in the cuticle, setae occasional on stipe as caulocystidia. Clamps present.
Type locality. Ketchen Creek, near Mesa Grande, San Diego County,
California.
Habit and habitat. Cespitose in humus near rotten oak logs, March.
Distribution. Known only from the type locality.
Observations. This species is clearly in the P. conopilea group, but, as dried,
is dull colored more as in basidiocarps of Psathyrella foenisecii. It is distinguished
in the group by its very large spores and cheilocystidia. No setae were found in
the hymenium.
233. Psathyrella conopilea (Fries) Pearson & Dennis, Trans. Brit. Mycol. Soc.
31: 185. 1948.
Agaricus conopilus Fries, Syst. Mycol. 1: 504. 1821.
Agaricus subatratus Fries, Epicr. Syst. Mycol. 238. 1838.
Psathyra conopilus (Fr.) Kummer, Fihr. Pilzk. 70. 1871.
Psathyra conopilea var. subatrata (Fr.) J. Lange, Dansk Bot. Arkiv 9(1): 14. 1936.
Drosophila subatrata var. conopilea (Fr.) Kiihner & Romagn. Fl. Anal. 354. 1953.
Agaricus graciloides Peck, Rep. N. Y. State Mus. 30: 42. 1878.
Psathyrella graciloides (Pk.) Saccardo, Sylloge Fung. 5: 1127. 1887.
Psilocybe castaneicolor Murrill, Mycologia 15: 19. 1923.
Hypholoma gracile F. E. & E. S. Clements, Cryptogamae Form. Coloradensium #387.
Illust. Peck, 1. c. pl. 1, figs. 1-4. P1. 73.
Pileus (15-)20-40 mm broad, obtusely conic to ovoid at first, the margin
straight, broadly conic to almost convex at maturity, glabrous and moist, smooth,
sometimes rugulose, striate on margin when moist, color at first russet to
"cinnamon-brown" or paler ("ochraceous-tawny"), hygrophanous and fading to
pale buff or avellaneous, sometimes darker, at times becoming almost dark
avellaneous before losing moisture, atomate when faded. Context watery and
extremely fragile, thin, odor and taste mild.
Lamellae close, narrow, adnate but soon seceding, pale alutaceous when young,
("cinamon-buff' or more cinnamon ("pinkish cinnamon"), soon dark blackish
brown from spores, edges white and fimbriate.
Stipe (6-)10-15 cm long, (2.5-)3-5 mm thick, equal, strict, fragile, splitting
readily, hollow, glabrous or faintly silky, dull white, veil rudimentary or lacking.