The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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differentiated. Pleurocystidia abundant, 42-60x10-15 /, fusoid-ventricose, the
neck elongated and apex subacute, wall thin, smooth and hyaline, cell content not
distinctive in either KOH or Melzer's. Cheilocystidia of two types, the first like
the pleurocystidia but smaller, and the second of vesiculose to clavate cells, the
latter not numerous. Caulocystidia 28-52x5-12 /a, irregularly fusoid with subacute to acute apex and thin hyaline refractive walls, content of cells not
distinctive.
Gill trama of interwoven more or less enlarged hyphae, dull brown in KOH
and smooth or with slight incrustations, finally dingy yellowish brown. Pileus
trama dark vinaceous-brown and with conspicuous incrustations and/or pigment
thickenings, not becoming appreciably paler; cuticle of a palisade of vesiculose
pedicellate cells to elliptic cells hyaline to slightly yellowish in KOH, cells 15-30 j/
wide and content not distinctive. Clamps present.
Type locality. Mt. Hood National Forest, Oregon.
Habit and habitat. Cespitose in small clusters on soil.
Distribution. Known only from the type locality.
Observations. This species is close to P. longicystis but differs in the wider
germ pore of the basidiospore, the longer and frequently forked cystidia and the
darkening lower portion of the stipe.
164a. Psathyrella rufogrisea var. riparia A. H. Smith, var. nov.
A typo differt: pleurocystidia 42-74x12-18 u; caulocystidia versiformiaclavata, globosa vel fusoide ventricosa: Typus. Smith 53268 (MICH); legit prope
McCall, Idaho.
Pileus 6-15 mm broad, obtusely conic, the margin straight at first, expanding
to broadly conic or nearly plane, surface when young coated with a superficial
layer of white fibrils radially arranged and rather coarse in texture, as pileus
expands the fibrils becoming arranged in radially disposed squamules, the margin
remaining fringed with fibrils for sometime, color "russet" on the disc, "cinnamonbrown" on the margin (dark rusty brown to dingy dark cinnamon), fading to
cinnamon-buff on disc and paler near the margin. Context very thin and delicate,
taste or odor not distinctive.
Lamellae close, adnate, seceding readily, dull brownish when young, becoming cocoa-brown and finally "hair brown" (dark grayish brown), edges even and
not appreciably fimbriate.
Stipe 3-4 cm long, about 1 mm thick, equal, very fragile, hyaline-gray at first
covered with white radially arranged fibrils of the veil, glabrescent and in age the
stipe naked except for a pruinosity over the apical region.
Spores 9-12.5x5-6 a, smooth, apical pore broad and apex often appearing
somewhat truncate, color in KOH chocolate-fuscous, in Melzer's bay-brown, shape
in face view oblong to narrowly elliptic, in profile obscurely bean-shaped to
subelliptic, wall about 0.4 A thick.
Basidia 4-spored, clavate, 8-10 u broad. Pleurocystidia scattered, 42-74 x 12 -18 a, fusoid-ventricose with apex acute to subacute, wall thin, smooth, and
hyaline, cell content not distinctive or with some refractive particles (revived in
KOH), not colored in Melzer's. Cheilocystidia similar to pleurocystidia but more
irregular in outline and more fusoid, the same size or smaller than the pleurocystidia. Caulocystidia versiform (globose, clavate, fusoid or fusoid-ventricose),
scattered to abundant near stipe apex, thin-walled, hyaline in KOH, smooth,
content not distinctive.