The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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laceus; fragilis; lamellae confertae, angustae, adnatae, rufo-cinnamomeae; stipes
2.5-5 cm longus, 1.5-3 mm crassus, deorsum fibrillosus, ad basin luteomyceliosus;
sporae 6.5-8 x 3.5-4.5 4; pleurocystidia 46-68 (-74) x 9-14 a, subfusoidea. Typus.
University of Toronto 9401 (MICH).
Pileus 1.5-3.5 cm broad, obtuse to convex becoming plane or slightly umbonate, faintly fibrillose over all or toward the appendiculate margin, moist,
hygrophanous, dark cinnamon-brown when moist, fading to clay color or
cinnamon-buff, when dried sometimes sordid tawny but usually clay-colored.
Context thin and fragile, odor and taste not recorded.
Lamellae close, narrow to moderately broad, adnate, dark reddish brown
("warm sepia") or darker when dried.
Stipe 2.5-5 cm long, 1.5-3 mm thick at apex, slightly enlarged downward,
hollow, when dried pale yellowish over all and fibrillose to unpolished over the
lower portion, base with a rather conspicuous yellowish mycelium; veil submembranous, when dried between "vinaceous-buff" and "pinkish buff."
Spores 6.5-8 x 3.5-4.5 f, smooth, apical pore present but inconspicuous, shape
in face view oblong to elliptic, in profile obscurely inequilateral to obscurely beanshaped, color in KOH rich cocoa-color darkening to chocolate-brown, in Melzer's
reddish tawny, wall about 0.3 pL thick.
Basidia 16-24x 6-8 a, 4-spored, narrowly clavate, hyaline in KOH. Pleurocystidia very abundant, 46-68(-74) x9-14 pa, subfusoid with the apex tapered to
a narrow flexuous neck and apex subacute, the wall smooth, thin and hyaline, the
cell content homogeneous and hyaline in KOH, in Melzer's having a large central
globule as wide as the cystidium and yellowish-hyaline. Caulocystidia not found
on the limited material available for examination.
Gill trama characteristically yellowish in KOH, the subhymenium darker, the
hyphae parallel or nearly so. Pileus with a cuticle formed by clavate to pearshaped cells staggered in such a way as not to form an even palisade, the layer
1-2 cells deep, the walls of the cells smooth and yellowish in KOH. Hyphae of
the context interwoven, yellowish or (at first) dark yellowish brown in KOH.
Clamp connections present.
Type locality. Hatchley, Brant County, Ontario, Canada.
Habit and habitat. On a rotten stump.
Distribution. Canada: Ontario. United States: Michigan, Washington.
Observations. Psathyrella fraxinophila has cystidia containing a globule in
the fresh material, but in time (several years in the herbarium) it fails to
reconstitute when cystidia are revived in KOH or Melzer's. In P. canadensis the
globule appears not to form in KOH but does in Melzer's regardless of the age of
the specimens. In P. delineata the globule is colored pale sulphur yellow and forms
in both KOH and in Melzer's.
Material examined. CANADA. Ontario (Type).
UNITED STATES. Michigan: A. H. Smith 36394, 74312; N. J. Smith 1777;
Thiers 3232. Washington: Smith 29994.
112. Psathyrella delineata (Peck) A. H. Smith, Contr. Univ. Mich. Herb. 5:
59. 1941.
Hypholoma delineatum Peck, Bull. N. Y. State Mus. 150: 83. 1911.
Drosophila delineata (Pk.) Murrill, Mycologia 14: 68. 1922.
Illust. P1. 50; P1. 53, fig. a; Text Fig. 271.
Pileus (3-)5-10 cm broad, obtuse, becoming convex to plane or slightly
umbonate, surface at first covered by a thin superficial coating of white silky