The North American species of Psathyrella.

1972]

PSATHYRELLA

363

white, thickened or subbulbous and whitish mycelioid at the base; veil lacking.
Spores 5-6.5x 3.5-3.8 pt, smooth, apical pore distinct under oil but apex not
appreciably truncate, shape in face view slightly wedge-shaped to oblong in
Melzer's, more ellipsoid in KOH, in profile view obscurely to somewhat beanshaped varying to suboblong, color in KOH dull cocoa-color becoming chocolatebrown, in Melzer's tawny, wall about 0.2 u thick.
Basidia 4-spored, 12-14x4.5-6 Iu, clavate, hyaline in KOH. Pleurocystidia
scattered, 26-42x9-14 /, broadly ventricose above a pedicel, with hardly any
neck, the apex broadly rounded, smooth, thin-walled, cell content not distinctive.
Cheilocystidia similar to the pleurocystidia. Caulocystidia scattered, clavate, up
to 20 ~ broad, hyaline and thin-walled.
Gill trama regular, of inflated hyphal cells, merely pallid brownish in KOH,
subhymenium cellular and hyaline. Pileus having a cuticle of vesiculose cells
1-2 deep, their walls hyaline to dingy ochraceous, smooth, cell content not distinctive. Hyphae of the context merely pale brownish in KOH (from a mature
basidiocarp). Clamps present.
Type locality. New York City, New York.
Habit and habitat. Gregarious or cespitose on soil or on decaying wood in
woods or open places.
Distribution. United States: California, Maine, Michigan, New York, Oregon,
Washington. Canada: Nova Scotia.
Observations. This species is obviously a segregate from P. hydrophila but
is distinguished by the lack or almost lack of a veil, the paler trama in KOH as
revived, and the tendency of the pileus color to fade out more quickly. In Michigan we first misidentified this species as a variant of P. hydrophila having only
a rudimentary veil. Drosophila laevissima Romagn. may be the same as
P. fuscofolia, a careful comparison should be made.
Material examined. UNITED STATES: California: White 30, 541. Maine:
Bigelow 3169, 3936, 3937, 4710, 4711. Michigan: Ammirati 1657, 2892; Bartelli
3157; Homola 9-27-64; Hoseney 1192, 1470; Smith 43056, 50420, 50913; 64617,
67542, 75214, 78273. New York: Peck's type. Oregon: Lawrence 11-3-57, 1156.
Washington: Smith 49460, 55714. CANADA. Nova Scotia: Harrison 8385.
336. Psathyrella ammiratii A. H. Smith, sp. nov.
Pileus 2-3 cm latus, late convexus, glaber, fulvo-cinnamomeus dein argillaceus;
contextu brunneolus; lamellae confertae demum subdistantes, demum lata, avellaneae, in exsiccatis vinaceo-brunneae; stipes 3-3.5 cm longus, 2-3 mm crassus,
albidus, sursum pruinosus, deorsum demum brunneus, glaber; spores 6-7 x 3-3.5 /;
pleurocystidia 36-48 (-54) x9-16 tL, utriformia vel lecythiformia, ad apicerum
5-9 A latus, in "KOH" saepe sublutea; fibulae adsunt. Typus. Ammirati 2834
(MICH); legit prope Big Bay, Michigan.
Pileus 2-3 cm broad, broadly convex expanding to plane, margin spreading in
age, surface glabrous, moist and hygrophanous, dark rusty brown when moist,
fading to "clay color," dark brown as dried, in age before fading the disc and the
incurved margin bister when moist and the spores are mature. Context thin,
fragile brownish, odor and taste not distinctive.
Lamellae close becoming subdistant, adnate, narrow to moderately broad,
brownish with a gray tint, when dried dark vinaceous-brown.
Stipe 3-3.5 cm long, 2-3 mm thick, equal, fragile, white pruinose above,