The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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because of the very pale spores. Apparently there is a fairly extensive series of
variants centering around P. hymenocephala, and one "line" features pale colored
spores and various stages, depending on the species, in the development of
brachybasidioles.
The following description is of a northern variant we tentatively assign to
P. singeri, but it is not clear at present whether a veil is present or not.
Pileus 2-3 cm broad, convex to plane or somewhat umbonate, glabrous, near
"wood brown" but with more of a grayish cast when moist, hygrophanous, near
avellaneous when faded and remaining near avellaneous when dried, margin striate
when moist, atomate over all when faded. Context very thin, fragile, paler than
the surface; odor and taste not recorded. When dried the pilei vinaceous-tan.
Lamellae adnate to adnexed, very narrow and crowded, edges even but whitish,
pale "Verona brown" (vinaceous-brown) at maturity.
Stipe 2.5-3.5 cm long, 1.5-2.5 mm thick, equal, fragile, hollow, glabrous, white.
Spores very pale dull "Verona brown" in mass (dull vinaceous-cinnamon);
6-7.5 x 4-5 pu, smooth, apical pore not evident (because of a relatively thin wall),
shape in face view elliptic to subovate, in profile obscurely bean-shaped to subelliptic, color in KOH almost hyaline, in Melzer's almost hyaline.
Basidia 22-24x 7.5-9 u, clavate, hyaline in KOH, 4-spored. Brachybasidioles
possibly differentiated in old pilei. Pleurocystidia none. Cheilocystidia voluminous, 18-28x 10-22 A, ellipsoid to balloon-shaped, thin-walled, very faintly
yellowish to hyaline in KOH.
Pileus with a cuticle formed by inflated cells in a layer about one cell deep,
pale cinnamon to yellowish revived in KOH. Hyphae of the trama mostly pale
cinnamon to yellowish in KOH, walls with cinnamon colored thickenings near the
septa at the base of the cuticle and including some hyphae of the subcuticular
region, some hyphae with incrustations. Clamps present. No distinctive color
changes occur in mounts revived in Melzer's.
Type locality. Rhododendron, Oregon.
Habit and habitat. On debris under mixed hardwoods and conifers.
Distribution. Oregon and Pennsylvania.
Observations. This variant is characterized by pale spores in KOH, the
vinaceous-cinnamon spore deposit, crowded narrow vinaceous-cinnamon gills, and
possibly by the lack of a veil. See p. 438 for data on Michigan collections.
45. Psathyrella jalapensis (Murrill) A. H. Smith, comb. nov.
Drosophila jalapensis Murrill, Mycologia 10: 65. 1918.
Pileus 4 cm broad, convex to plane, not umbonate, surface glabrous, hygrophanous, striate, dull avellaneous-isabelline, with isabelline disc, margin entire,
concolorous. Context thin and fragile.
Lamellae adnate, crowded, rather narrow, dark purplish brown at maturity.
Stipe 14 cm long, 4 mm thick, long and slender, equal or tapering slightly
upward, smooth, glabrous, white, fragile, hollow.
Spores 7-9.5x4.5-5.5 /L, smooth, ellipsoid, chocolate color when revived in
KOH, with an apical hyaline pore.
Basidia 4-spored, 16-18 x 9-10 pt, hyaline in KOH. Brachybasidioles not developed. Pleurocystidia none. Cheilocystidia abundant, hyaline in KOH, 28-40x
9-14 tA, ventricose to subcylindric, with rounded apex, some merely fusoidventricose and obtuse, wall thin, smooth and hyaline, readily collapsing.
Gill trama of greatly enlarged cells more or less regularly arranged, hyaline in