The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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hygrophanous, glabrous except for the remains of the pallid veil along the margin
or with scattered particles over the marginal area, glabrescent, "ochraceoustawny" (yellowish fulvous) when young and moist, dull reddish cinnamon when
mature, fading to pallid alutaceous. Context thin and fragile, concolorous with
surface when moist or faded, odor not distinctive, taste not recorded.
Lamellae pallid then brownish and near "wood brown" (gray-brown) when
spores are mature, broadly adnate, close becoming subdistant, edges even.
Stipe 2-3 cm long, 1.5-2.5 mm thick, equal, fragile, faintly fibrillose from the
veil but glabrescent, white to pallid but becoming honey-color at the base.
Spores 7-9(-10) x 3.8-4.5(-5) A, smooth, apical pore present but spore apex
not truncate, shape in face view oblong to elliptic, varying to ovate in longer
individuals, in profile obscurely inequilateral varying to somewhat bean-shaped
to narrowly ovate, color revived in KOH bright cocoa-color, becoming chocolate
color slowly, in Melzer's ochraceous-tawny to tawny, wall about 0.3 g thick.
Basidia 4-spored, 26-32x8-10,u, hyaline in KOH or slightly cinnamon at
base of pedicel revived in KOH. Pleurocystidia 40-60 x 9-14 g/, fusoid-ventricose,
wall thin, smooth and hyaline, cell content not distinctive, apex subacute to
obtuse, a fair number of cystidia with 2 protrusions (rabbit ears) to form a double
apex. Cheilocystidia clavate to saccate 18-28x9-15 g, hyaline or hyaline with
yellowish base (revived in KOH). Caulocystidia-no significant ones found on
revived portions of the type.
Gill trama of inflated cells, regular, the walls cinnamon as revived in KOH
and with some pigment deposits. Pileus trama with hyphae of subcuticular zone
rusty cinnamon in KOH and very conspicuously incrusted with cinnamon pigment; pileus cuticle a palisade of clavate-pedicellate upright cells with cinnamon
walls varying to yellowish (revived in KOH). Clamp connections present.
Type locality. Colonial Point, Burt Lake, Cheboygan County, Michigan.
Habit and habitat. Gregarious on sandy humus in cut-over hardwoods.
Distribution. Michigan; Smith 33628 (Type), 33740.
Observations. The conspicuously incrusted subcuticular hyphae, the colored
pedicels of the basidia, and the well-formed palisade layer forming the cuticle of
the pileus are distinctive.
389. Psathyrella seymourensis A. H. Smith, sp. nov.
Pileus 7-15 mm latus, convexus, ad marginem tenuiter fibrillosus, glabrescens,
fulvus; lamellae latae, subdecurrentes, brunneolae demum purpureo-brunneae;
stipes 1-2 cm longus, circa 1 mm crassus, pallidus demum brunneolus, sparse
fibrillosus; velum parvum; sporae 7.5-9 x 4-4.5 (-5) tu; pleurocystidia 32-46 x
8-12 j, acute fusoideo-ventricosa (cum collis prae-elongatis); fibulae adsunt.
Typus. Smith 18931 (MICH); legit prope Milford, Michigan.
Illust. Text Figs. 846-848.
Pileus 7-15 mm broad, convex becoming broadly convex, at first with scattered
fibrils along the margin from the remains of the almost rudimentary veil, soon
entirely glabrous, faintly striate when moist, hygrophanous, tawny ("ochraceoustawny") fading to pale tan ("cinnamon-buff"). Context very thin, pallid brownish moist, pale tan faded, odor and taste not distinctive.
Lamellae broad, arcuate-subdecurrent or merely broadly adnate, not seceding,
subdistant, 1-2 tiers of lamellulae, pallid brownish becoming dark purplish brown,
the edges faintly whitish.
Stipe slender, 1-2 cm long, about 1 mm thick, pallid to dull brown, becoming