The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

Pileus epicutis a compact layer - 50 f thick, 4-6 cells deep, cells appearing brown
to amber in mass but are individually hyaline to yellowish with thin to slightly
thickened smooth walls, subglobose, ellipsoid, or clavate, 15-30(-50) u broad.
Clamps present. All hyphae yellowish in Melzer's.
Habit, habitat and distribution. Gregarious to cespitose in deep conifer needle
mold along a decaying conifer limb (in a spruce-hemlock woods); Turnagain
Pass, Seward Highway, Alaska, Wells & Kempton 184 (Type), 185.
Observations. The two collections cited above were apparently growing from
the same mycelium. Both were collected the same year, 1962, the first on July 23
and the other on September 6. We have not seen this species either before or
since these collections were made though the area is one of our prime collecting
areas. It is a species distinct from all other Alaskan Psathyrellae by its large
size, nonhygrophanous pileus, more or less angular spores as seen in face view,
and its decidedly capitate to subcapitate pleurocystidia. It appears to be most
similar to P. larga and P. subvinacea but differs in the features as described.
414. Psathyrella velatipes A. H. Smith, sp. nov.
Pileus 1.5-5 cm latus, obtusus demum convexus vel planus, ad marginem
fibrilloso-zonatus, glabrescens, umbrino-cinnamomeus demum "avellaneus" et
sericeus, saepe rugulosus; fragilis; odor subpungens; lamellae confertae, adnatae,
secedentes, pallide brunneae demum griseobrunneae; stipes 3-7 cm longus, 2-5 mm
crassus, fragilis, albidus vel sordidus, valde albido-floccosus vel subsquamulosus;
sporae 8-10 (-11) X 5-6 u; pleurocystidia 38-56 x 8-14 A, fusoide ventricosa vel
subeylindrica, obtusata; cheilocystidia 18-26 X 7-12 /, clavata, in KOH subochracea. Typus. Smith 80623 (MICH); legit Ann Arbor, Michigan, 30 Sept.
1971, ad terram.
Pileus 1.5-3 cm broad, obtuse when young, soon broadly convex and in age
plane or the margin uplifted slightly, at first with a faint zone of fibrils along the
margin and a few scattered fascicles near the edge, cap surface soon glabrous over
all; color dull "warm sepia" (dark cinnamon) moist, and fading to "avellaneous"
or paler, appearing somewhat silky after fading or some more or less atomate,
smooth to slightly rugulose. Context fragile, odor faint but somewhat penetrating.
Lamellae close, broad, adnate, seceding, pallid brownish, at maturity near
"drab" to grayish chocolate color, edges even.
Stipe 3-7 cm long, 2-5 mm thick, equal, fragile, white but dull, distinctly
white-squamulose to loosely fibrillose (floccose) in age but no distinct annular
zone present, only slightly discolored beneath the squamules in age.
Spore deposit dark chocolate-brown. Spores 8-10 (-11) x 5-6,u, smooth, apical
pore present as a broad thin hyaline area bounded by a dark line (apex not
truncate); shape in face view elliptic to oblong, in profile subelliptic; color dark
chocolate in KOH, slowly changing to date brown (but many pale spores in
mounts also), reddish bay in Melzer's.
Basidia 4-spored, hyaline in KOH, clavate. Basidioles clavate. Pleurocystidia
scattered to rare, 38-56x 8-14 /A, subeylindric with obtuse apex, or forked near
apex, or fusoid-ventricose with a subacute to obtuse apex, hyaline in KOH, thinwalled, content not distinctive. Cheilocystidia 18-26 x 7-12 /t, mostly clavate and
with yellowish walls as revived in KOH. Caulocystidia versiform, present as the
end cells of the loosely woven hyphae covering the stipe, hyaline, smooth, thinwalled and varying greatly in size.
Gill trama of subparallel inflated hyphae hyaline to brownish in KOH; sub