The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Basidia 4-spored, 17-20 x 5-7 I, hyaline to flushed vinaceous-brown (in KOH).
Pleurocystidia scattered, 30-46 x 7-14 A, ventricose and abruptly tapered distally
to a narrow neck ending in an acutely pointed apex; wall smooth or apex occasionally with adhering granules in KOH, hyaline or in the pedicel vinaceousbrown, thin; cell content not distinctive or with a few refractive particles in some.
Cheilocystidia similar to pleurocystidia but often longer and some yellow to
hyaline vesiculose to clavate cells also present.
Gill trama rich vinaceous-cinnamon in KOH, regular, walls smooth. Pileus
cuticle a layer of vesiculose cells 2-3 deep; the walls vinaceous-cinnamon to nearly
hyaline, smooth, thin. Hyphae of trama dark vinaceous-cinnamon in KOH, pigment encrusted on the wall and/or as thickenings in the wall-usually near the
septa, the vinaceous-cinnamon color persistent in KOH. Clamps present.
Type locality. Wilderness State Park, Emmet County, Michigan.
Habit and habitat. Scattered on moist earth where brush piles have been
burned.
Distribution. Known only from the type locality.
Observations. The strong KOH color reactions of the gill trama, small more
or less pointed pleurocystidia, very small spores, purplish spore deposit, rusty
brown gills and possibly the habitat are distinctive (but the only other collection
assigned here was from conifer duff).
78. Psathyrella confertissima (Atkinson) A. H. Smith, Contr. Univ. Mich. Herb.
5: 33. 1941.
Hypholoma confertissimum Atkinson, Proc. Am. Phil. Soc. 57: 355. 1918.
Hypholoma oblongisporum Parker, Mycologia 25: 179. 1933.
Illust. Parker, op. cit. pl. 26, fig. 4; pl. 27, fig. 20; pl. 29, fig. 30. P1. 38.
Pileus 1-3.5 cm broad, obtusely conic becoming more or less convex, surface
at first covered by remains of the white floccose universal veil, the margin appendiculate, glabrescent, hygrophanous, pallid argillaceous finally becoming pallid
ochroleucous or whitish, disc argillaceous and rugulose, ashy brown in age or
streaked or spotted this color. Context thin, fragile.
Lamellae adnexed, seceding, crowded, elliptic, ashy then purplish-brown, edges
white.
Stipe (5-)10-20 cm long, 3-5 mm thick, equal, straight or flexuous, white,
hollow, white floccose-squamulose, fragile, base furnished with a well developed
pseudorhiza which gives rise at the ground level or near it to a large cluster of
basidiocarps bound together to some extent by a yellow mat of mycelium.
Spores 5-6x3-3.5 ~E, smooth, truncate at apex from a broad inconspicuous
pore, shape in face view suboblong (often with a slight medial depression or constriction), in profile somewhat bean-shaped or showing a medial constriction, color
in KOH soon medium chocolate-gray, in Melzer's reddish tawny, wall about
0.2.L thick.
Basidia 4-spored, 16-19x3.5-5 ~, clavate, hyaline in KOH. Pleurocystidia
30-56x9-16 j, fusoid-ventricose with acute to subobtuse apex, smooth, thinwalled, hyaline in KOH or with a very pale diffuse brownish content as revived
in KOH. Cheilocystidia 26-44 x 8-14,, similar to pleurocystidia but shorter and
apex more obtuse, hyaline in KOH. Caulocystidia not located except for a few
clavate hyphal ends.
Gill trama regular, subparallel, hyaline in KOH. Pileus having a cuticle of
inflated hyaline cells several cells deep, the cells 10-30 pu wide, hyaline or nearly