The North American species of Psathyrella.

1972]

PSATHYRELLA

225

182. Psathyrella pseudosenex A. H. Smith, sp. nov.
Pileus 1-2 cm latus, convexus, albo-floccosus glabrescens, pallide spadiceus,
ad centrum cinnamomeo-brunneus; lamellae confertae, adnatae, pallidae demum
brunneo-griseae; stipes 2-3 cm longus, 1.5-2 mm crassus, albidus, deorsum sordide
brunneus, floccoso-fibrillosus, glabrescens; sporae 6-8 x3.5-4 t; pleurocystidia
34-46 x 9-14 p, fusoide ventricosa; fibulae adsunt. Typus. Smith 22312 (MICH);
legit prope Douglas Lake, Michigan.
Illust. Text Figs. 412, 413a, 414.
Pileus 1-2 cm broad, convex, remaining so or becoming merely more broadly
expanded, surface at first covered by delicate white flecks of fibrils of outer veil
material, these soon evanescent, the margin at first fringed with white fibrils,
surface moist and hygrophanous, when moist near "tawny olive" over marginal
area and cinnamon-brown over the disc, fading to pale buff. Context very delicate, fragile, watery, brownish fading to pallid, odor and taste not distinctive.
Lamellae close, broad, adnate, readily seceding, pallid becoming drab (dark
brownish gray), edges uneven.
Stipe 2-3 cm long, 1.5-2 mm thick, equal, white, base slightly sordid brown,
lower two-thirds white floccose-fibrillose, upper portion white and pruinose.
Spores 6-8 x 3.5-4,u, smooth, apical pore present and in some apex appearing
truncate, or hyaline membrane over the pore protruding bubble-like, shape in face
view ovate to elliptic, in profile mostly obscurely inequilateral, color in KOH dull
cinnamon-brown slowly becoming chocolate color, in Melzer's reddish tawny, wall
about 0.3 t thick.
Basidia 16-20 x 7-9 fi, short-clavate, hyaline in KOH, 4-spored. Pleurocystidia
scattered, 34-46 x 9-14 IA, fusoid-ventricose with obtuse apex, and the protoplasmic
content not extending quite to the apex in many, wall thin, smooth and hyaline,
content of cells not distinctive in KOH or in Melzer's. Caulocystidia subclavate,
fusoid-ventricose or subcylindric, smooth, wall thin but in some refractive, smooth,
cell content not distinctive.
Cuticle of pileus a layer of vesiculose cells 1-2 deep, the walls toward the
subcuticular region pale cinnamon, cell content not distinctive. Hyphae of subcuticular region cinnamon to pale cinnamon in KOH with few pigmented wall
thickenings. Clamp connections present. No distinctive reactions noted on any
tissue as revived in Melzer's.
Type locality. Near Cheboygan, Michigan.
Habit and habitat. Around decaying stumps of hardwoods, August.
Distribution. Michigan and California.
Observations. This species is distinct from P. senex in having narrower spores.
Both have relatively thin outer veils. P. laricina keys out here also but is
terrestrial, the hymenium contains brachybasidioles at maturity, and the pleurocystidia have narrow necks and acute apices.
Material examined. California: White 214. Michigan: Smith 22312 (Type).
183. Psathyrella fibrillosipes A. H. Smith, sp. nov.
Pileus 8-15 mm latus, demum late convexus, albo-floccosus glabrescens, ad
marginem appendiculatus vel fimbriatus, fumoso-fulvus; lamellae latae, subdistantes, subhepaticolor; stipes 1.5-2.5 cm longus, circa 1.5 mm crassus, copiose
fibrillosus, albus; sporae 6-7.5(-8) x3-3.5 A; pleurocystidia 36-48x7-13 U,
anguste fusoideo-ventricosa, subacuta; fibulae adsunt. Typus. Smith 32-455
(MICH); legit prope Stockbridge, Michigan.