The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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279. Psathyrella fagetorum A. H. Smith, sp. nov.
Pileus 1-2 cm latus, 1.5 cm altus, conicus vel campanulatus, ad marginem
sparse fibrillosus glabrescens, alutaceus; contextu alutaceus; lamellae confertae
latae, brunneolae demum violaceo-brunneae; stipes 2-3 cm longus, 1.5-2.5 mm
crassus; deorsum melleibrunneus, fibrillosus glabrescens; sporae 8-10(-11) x
4.5-6 /; pleurocystidia 38-47 (-55) x 10-16 a, fusoide ventricosa vel late fusoidea,
obtusa; fibulae adsunt. Typus. Smith 78117 (MICH); legit Tahquamenon Falls
State Park, Luce County, Michigan.
Illust. Text Figs. 590-596.
Pileus 1-2 cm broad at base and 1.5 cm high, obtusely conic, expanding to
campanulate, at first with a few scattered fibrils over marginal area and the edge
with a delicate fringe, soon completely glabrescent, when moist dull tawny on the
disc and paler (pale tan) on the margin, translucent striate moist, as spores mature
the marginal area becoming pale chocolate-gray (near wood brown). Context
thin, fragile, concolorous with pileus, odor and taste not distinctive, with FeSO,
no color change.
Lamellae close, broad, adnate, pinkish buff (pale watery tan), becoming
"cinnamon-drab" (violaceous-brown with only a faint cinnamon tint).
Stipe 2-3 cm long, 1.5-2.5 mm thick, equal, hollow, fragile, dull honey brown
over basal third beneath the white fibrils of the veil, pallid above.
Spores 8-10(-11) x 4.5-6 a, smooth, apical pore well-defined as a hyaline lensshaped cap, in face view the spore oblong to elliptic or weakly ovate, in profile
subelliptic to obscurely inequilateral, color in KOH dark bister at first, slowly
dark chocolate color, in Melzer's dark reddish tawny, wall about 0.4 [u thick.
Basidia 18-24 x 7-9 u, 4-spored, hyaline, clavate. Pleurocystidia 38-47 (-55) x
10-16 u/, fusoid-ventricose with obtuse apex varying to broadly and obtusely
fusoid, wall thin and smooth, hyaline or weakly yellowish in the ventricose part,
content not distinctive. Cheilocystidia resembling the pleurocystidia, rarely are
clavate to vesiculose cells present. Caulocystidia mostly clavate and extremely
variable in size, thin-walled, a few utriform to subvesiculose cells present with
slightly thickened yellowish walls in KOH.
Pileus cuticle a layer of vesiculose cells 2-3 deep, the walls thin, smooth,
hyaline to pale ochraceous-cinnamon in KOH, cell content not distinctive. Hyphae
of trama including a subcuticular zone vinaceous-cinnamon in KOH as is the gill
trama also, walls smooth or minutely roughened. No distinctive reaction on any
tissue in Melzer's. Clamps present.
Type locality. Tahquamenon Falls State Park, Luce County, Michigan.
Habit and habitat. Scattered on a mossy beech log.
Distribution. Michigan.
Observations. The spores are too large for either P. obtusata or P. fulvescens
and the veil is too thin for subgenus Pannucia.
280. Psathyrella orbitarum (Romagnesi) Moser in Gains, Kleine Krypto. Fl. 215.
1967.
Drosophila orbitarum Romagnesi, Bull. Mens. Soc. Linn. Lyon 21: 152. 1952.
Illust. Text Figs. 597, 598.
Pileus 5-15 mm broad, obtusely conic to convex, becoming broadly convex to
nearly plane, surface glabrous, moist, hygrophanous, atomate when faded, at first
dingy ochraceous-tawny on the disc, dingy cinnamon-brown near the margin,