The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

atomate, not striate when moist. Context thin, fragile, very delicate, odor and
taste not distinctive.
Lamellae white becoming avellaneous, close, adnate, moderately broad, edges
whitish, crenate under a lens.
Stipe 1-2 cm long, 1.5 mm thick, equal, fragile, hollow, white but pale honey
color in cortex lower down, finely covered with soft white fibrils from the veil up
to an evanescent zone.
Spore deposit avellaneous. Spores 6-7.5 x 3.5-4.5 I, dull cocoa-color in KOH,
grayer and paler on standing, shape in profile obscurely bean-shaped to obscurely
inequilateral, in face view elliptic to ovate, germ pore broad but inconspicuous.
Basidia 4-spored. Pleurocystidia absent. Cheilocystidia obtusely fusoidventricose to somewhat utriform, 38-56x 10-15 xA, thin-walled, content in apex
usually consisting in part of refractive particles. Cuticle of pileus a layer of
inflated cells 2-3 deep, hyaline or nearly so in KOH. Subcutis nearly hyaline in
KOH, fading on standing. Clamps present.
Habit, habitat and distribution. On hardwood sticks, Webster Church area,
Washtenaw County, Michigan, July 14, 1970, Smith 78378.
Observations. This species is distinguished in the Candolleana by the refractive debris in the apex of the cheilocystidia, the copious universal veil, and the
very delicate stature.
412. Psathyrella tenacipes A. H. Smith, sp. nov.
Pileus 1-4 cm latus, obtuse conicus demum late expansus, tenuiter fibrillosus,
glabrescens, demum rugulosus, subspadiceus demum argillaceus; contextus fragilis, odor et sapor insipidus; lamellae sordide melleae demum violaceo-brunneae,
confertae, latae (5 mm); stipes 3-6 cm longus, 2-3.5 mm crassus, fibrosus, fistulosus, cartilagineus, pallidus; deorsum tenuiter fibrillosus, subsordidus; sporae
7-9x4.5-5.5 /a, leves, truncatae, late ellipticae; pleurocystidia 38-57x9-15 a,
fusoide ventricosa, rotunata vel obtusa Typus. Smith 28717 (MICH); legit prope
Douglas Lake, Cheboygan County, Michigan, 13 June 1948. Singer, De Gilio et
Smith 28717.
Pileus 1-4 cm broad, obtusely conic to subconvex, expanding to broadly convex
or with a slight umbo, buttons with a thin coating of appressed white fibrils over
marginal half, very soon entirely glabrous, becoming distinctly rugulose, when
fresh and moist "bister" but soon "Saccardo's umber," fading to clay-color and
finally wood-brown as spores mature. Context thin, fragile, brownish, no distinct
odor or taste.
Lamellae dull yellowish brown except for pallid brownish edges, at maturity
dark wood brown, close, broad (+5 mm), adnate, seceding, edges even.
Stipe 3-6 cm long, 2-3.5 mm thick, equal, rather stringy and fibrous, cartilaginous-pliant, tubular, white and unpolished or lower down thinly coated
with veil fibrils below at least at first, becoming off-white in age but not
discoloring distinctively.
Spore print near "benzo brown" (violaceous brown). Spores 7-9x4.5-5.5 Iu,
smooth, apex truncate, shape in face view broadly elliptic to slightly ovate, in
profile subelliptic to obscurely inequilateral, color reddish in H20 fresh, revived
in KOH dark cocoa-color, in Melzer's pale bay to tawny red; wall about 0.3 fi
thick.
Basidia 4-spored, 18-26x8-10 gt, clavate, hyaline; pleurocystidia 38-57x
9-15 a, fusoid-ventricose, apex obtuse to rounded, neck 5-7 Lx wide, apex 4-8 i