The North American species of Psathyrella.

376

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

inequilateral to subelliptic (the ventral line nearly straight and the dorsal line
convex as seen in optical section), color in KOH pale to medium fuscous, in
Melzer's bright reddish tawny, wall about 0.5 t, thick.
Basidia 4-spored, clavate, 8-9 / wide, hyaline in KOH. Pleurocystidia 26-38
(-45) x 8-12 pA, subfusoid to fusoid-ventricose, content not distinctive in KOH or
Melzer's, smooth, wall thin or in some about 0.5 / thick and yellowish in KOH.
Cheilocystidia 24-37x7-13 p/, clavate, broadly fusoid- or fusoid-ventricose,
smooth, with thin or very slightly thickened walls. Caulocystidia rare to absent,
if present clavate to cystidioid and similar to or slightly larger than the
cheilocystidia.
Pileus cuticle 1-2 cells deep, of greatly inflated cells with more or less thin,
hyaline to yellowish walls. Hyphae beneath the cuticle dingy yellowish in KOH
but smooth, slowly becoming nearly hyaline. Clamps present. No amyloid
reaction present in any tissue.
Type locality. Ophir, Colorado.
Habit and habitat. Clustered on soil around conifer logs and stumps, August.
Distribution. Colorado, New Mexico.
Observations. The clustered habit (but lack of a pseudorhiza), small pleurocystidia, the very rudimentary veil, spores 8-10 x 4.5-6,/, long stipe not changing
color appreciably in aging, and lack of red or cinnamon in the gills are distinctive.
It appears to be closely related to P. microsperma. It is readily distinguished from
the latter by larger spores.
Material examined. Colorado: Smith 52743 (Type). New Mexico: Barrows
3018.
350. Psathyrella rugoradiata Hesler & A. H. Smith, sp. nov.
Pileus 1.5-3 cm latus, convexus vel campanulatus, spadiceus, rugulosus, ad
marginem leviter floccosus, glabrescens; lamellae subdistantes, latae, albidae
demum fusco-griseae; stipes 5-8 cm longus, 3-4 mm crassus, candidus; deorsum
fibrillosus; velum sparsum, albidum; sporae 7-10x4.5-5 A; pleurocystidia 46 -64 x 9-12 (-15) p, anguste fusoideo-ventricosa, flexuosa, ad apicerum obtusa; fibulae adsunt. Typus. Hesler 22432 (MICH); legit prope Indian Gap, Great Smoky
Mountains National Park, Tennessee.
Pileus 1.5-3 cm broad, convex-campanulate, not fully expanding, hygrophanous, "bister" (dark yellow-brown) when young and moist, fading to "light
ochraceous-buff," glabrous; margin striate and radially rugulose, at first with thin
patches of the white fibrillose veil. Context fragile, pale buff, thin, odor and taste
mild.
Lamellae adnate, ascending, medium broad, subdistant, white at first, finally
"hair brown" (dark brownish gray), edges white-fimbriate.
Stipe 5-8 cm long, 3-4 mm thick, fistulose, white, shining, fibrillose-striate,
equal; veil white.
Spores 7-10 x 4.5-5 u, smooth, apical pore distinct causing apex to be narrowly
truncate, elliptic to slightly obovate in face view, in profile somewhat bean-shaped,
in KOH dark coffee-brown becoming slowly dark chocolate-color, wall about 0.3 j
thick.
Basidia 17-22x7-8 a, clavate, 4-spored. Pleurocystidia scattered, 46-64x
9-12 (-15) I,, mostly narrowly ventricose with flexuous walls in the neck and the
apex obtuse, varying to more broadly fusoid-ventricose, wall thin, smooth and