The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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by white squamules of outer veil fibrils but soon glabrescent over the center,
margin coarsely denticulate-appendiculate from the white submembranous inner
veil, color dark bay to cinnamon-brown when young and fresh and dark brownish
when faded or dried. Context thin, concolorous with the surface, fragile, odor and
taste not distinctive.
Lamellae close, becoming moderately broad, adnate, dull brown when young,
near "warm sepia" as dried (dark dull vinaceous-brown), edges even.
Stipe short, 2-4 cm long, 2-5 mm thick, equal, hollow, fragile, watery white
and not discolored below appreciably, with a thin coating of white fibrils to an
evanescent fibrillose zone.
Spores dark purple-brown in deposit, 7-9 (-10) x 4.5-5 (-6) pu, smooth, apical
pore present but apex at most only obscurely truncate, shape in face view elliptic
to ovate, in profile obscurely inequilateral to subelliptic, color in KOH dark
cocoa-color slowly becoming chocolate-brown, tawny in Melzer's, wall about
0.3 tu thick.
Basidia 4-spored, 18-23 x 8-10 u, broadly clavate, hyaline in KOH. Brachybasidioles differentiated. Pleurocystidia 32-44(-67) x 9-14 u/, scattered, fusoid to
fusoid-ventricose, apex acute to subacute, walls very thin, smooth and hyaline,
varying to narrowed to a subcapitate apex with wall slightly thickened in the
apex, some narrowly fusoid-ventricose with obtuse apex. Cheilocystidia clavate
to short and subfusoid, 25-38 x 8-13 /u, hyaline in KOH, scattered cells somewhat
resembling the pleurocystidia also present.
Pileus cuticle of inflated cells 1-3 deep and with thin walls brownish to hyaline
in KOH. Hyphae of subcutis vinaceous-cinnamon in KOH, slowly fading to
brownish, hyphae smooth or nearly so. Clamp connections present.
Type locality. Priest Lake, Idaho.
Habit and habitat. Cespitose on sand at the side of a dirt road, September.
Distribution. Idaho.
Observations. This species differs from P. vialis in its thicker stipe, smaller
spores and more appendiculate pileus margin. The inner veil is submembranous.
Material examined. Idaho: Smith 53710 (Type), 54232, 55064, 55079.
131. Psathyrella owyheensis A. H. Smith, sp. nov.
Pileus 1.5-4 cm latus, obtuse-campanulatus demum convexus, ad marginem
appendiculatus, glaber, mellei-cinnamomeus; lamellae subdistantes latae, pallidae
demum sordide cacaocolor; stipes 4-7 cm longus, 3-6 mm crassus, albidus, glaber;
sporae 7.5-10 x 4.5-5 t; pleurocystidia 36-48 x 9-13?, late fusoide ventricosa vel
subcapitata; fibulae adsunt. Typus. Trueblood 3135 (MICH); legit Owyhee
County, Idaho.
Pileus 1.5-4 cm broad, obtuse when young, expanding to obtusely campanulate,
broadly convex-umbonate or nearly plane, margin bent inward at first and
appendiculate with fragments of a pallid evanescent submembranous veil, glabrous over the remainder of the surface, hygrophanous, pale cinnamon to honeytan when moist and fading out to a pale pinkish buff or (as dried) pallid. Context
concolorous with surface either moist or faded, reasonably firm for a Psathyrella,
odor and taste not distinctive.
Lamellae nearly subdistant at maturity, broad, depressed adnate, pallid when
very young, becoming brownish and dingy cocoa-brown but when dried a dingy
pallid brownish (as if partly sterile), edges even or nearly so, concolorous with
faces.