The North American species of Psathyrella.

1972]

PSATHYRELLA

373

Illust. Text Figs. 776-779.
Pileus 10-25(-30) mm broad, obtusely conic with a straight margin at first,
expanding to broadly conic or plane, surface moist and hygrophanous "Mars
brown" (dark rusty brown) fresh, fading to dingy tan, when faded the surface
conspicuously rugulose. Context concolorous with the surface, taste mild, odor
fragrant.
Lamellae dull brown becoming dark rusty brown (like the pileus) when
mature, close, adnate, seceding, 2-3 tiers of lamellulae, moderately broad, edges
even.
Stipe 3-5 cm long, 1-2.5 mm thick, equal or nearly so, whitish but basal
mycelium yellowish, faintly pruinose over apical region, silky downward, veil
rudimentary and leaving only scattered fibrils.
Spores 5-6 x 2-3.5 p, smooth, apical pore present, shape in face view ovate to
corn-kernel-shaped, in profile subelliptic to somewhat inequilateral or obscurely
bean-shaped, color in KOH pale fuscous with an ochraceous reflection, reddish
tawny in Melzer's, wall about 0.2 J thick.
Basidia 4-spored, 16-20 x5-6 /, hyaline in KOH. Pleurocystidia 28-45 X
9-12 x 6-9 /u, nine-pin-shaped with the apex capitate, wall thin, smooth and
hyaline in KOH, content not distinctive in either KOH or Melzer's. Cheilocystidia
clavate, vesiculose or varying to similar to the pleurocystidia, hyaline and thinwalled (in KOH) or rarely a vesiculose cell with yellow wall also present. Caulocystidia versiform: (1) clavate to vesiculose-pedicellate and with the wall slightly
thickened (0.5 pt) and yellow in KOH, variable in size; (2) cells similar to
pleurocystidia; (3) various shapes intermediate between the first two types.
Pileus cuticle of large vesiculose cells in a layer 2-3 cells deep, the walls hyaline
or yellowish in KOH, smooth. Tramal hyphae brownish in KOH fading to nearly
hyaline, smooth. Clamp connections present. No distinctive reaction in any tissue
when mounted in Melzer's.
Type locality. Upper Payette Lake, Valley County, Idaho.
Habit and habitat. Cespitose on conifer debris, August.
Distribution. Idaho.
Observations. This species has the appearance of P. hydrophila but grows on
a conifer substrate, has a fragrant odor and has differently shaped spores in face
view among other features.
347. Psathyrella mucrocystis A. H. Smith, sp. nov.
Pileus 1-3 cm latus campanulatus vel expanso-umbonatus, fulvus, glaber; odor
leviter fragrans; lamellae confertae, latae, brunneolae demum fulvae dein fumosofulvae; stipes 3-5 cm longus, 4-7 mm crassus, pallidus, deorsum fibrillosus vel
subsquamulosus; velum "pale pinkish buff"; sporae 7-8.5 x 4-4.5 n; pleurocystidia
28-37x8-14 a, clavato-mucronata vel clavata; fibulae adsunt. Typus. Smith
65384 (MICH); legit prope Cascade Lake, McCall, Idaho.
Illust. Text Figs. 780-783.
Pileus 1-3 cm broad (all were immature), obtuse with the margin straight or
only slightly incurved, expanding to campanulate or umbonate and with a spreading margin, surface dark rusty brown moist, fading to bright ochraceous-tawny,
margin remaining fringed with fibrils until near maturity; veil fibrillose pallid
buff. Context thick and firm, pale buff, odor faintly fragrant, taste mild, FeSO,
no reaction.