The North American species of Psathyrella.

1972]

PSATHYRELLA

145

Habit and habitat. Scattered on decaying leaves.
Distribution. Michigan, New Mexico, Tennessee.
Observations. The bitterish aftertaste and the distinctly inrolled margin of
the pileus along with the lubricous pileus distinguish it from P. spadiceogrisea.
Its relationships are with the latter as the degree of veil development varies
considerably.
Material examined. Michigan: Kauffman 10-2-26; Smith 9508, 15019 (Type),
20362, 20616, 20620, 20714, 20906, 21026, 21142, 21285, 21313, 21340, 21344, 25213,
28667, 28704, 28706, 28752, 32192, 36172. New Mexico: Barrows #1. Tennessee:
Boarts 16405; Hesler 15833.
99. Psathyrella flexuosipes A. H. Smith, sp. nov.
Pileus 3-4 cm latus, 3-3.5 cm altus, conicus, sparse fibrillosus, ad marginem
appendiculatus, pallide spadiceus; lamellae confertae, angustae, sordide luteolae,
demum umbrino-fulvae; stipes 12-14 cm longus, 4-5 mm crassus, fragilis, albofibrillosus, glabrescens, deorsum sordide brunneus, flexuosus; sporae 7-9 x 4-5 [;
pleurocystidia 50-70x 8-15 ), pedicellato-elliptica vel subfusoidea, ad apicerum
rotundata vel subcapitata; fibulae adsunt. Typus. Smith 3269 (MICH); legit
prope Pysht, Washington.
Illust. Text Figs. 247, 248.
Pileus 3-4 cm broad across the base and 3-3.5 cm high, broadly conic, surface
at first covered by appressed superficial white fibrils, the margin decorated with
thick cottony patches of veil tissue, when moist "buckthorn brown" (dull yellowish brown), hygrophanous, fading to sordid buff and becoming radially rugose,
at times somewhat crenate along the margin, scarcely striatulate when moist.
Context thin, fragile, brownish, odor and taste mild.
Lamellae narrow, close, bluntly adnate, sordid buff when young, slowly becoming dark dull rusty brown, edges minutely fimbriate.
Stipe 12-14 cm long, 4-5 thick, equal, fragile, hollow, at first covered by
patches of white fibrils and appearing silvery, often flexuous, in age somewhat
glabrescent and sordid brownish, surface becoming slightly undulating finally.
Spores 7-9x4-4.5 u, smooth, somewhat truncate at apex from a distinct
apical pore, shape in face view elliptic to narrowly ovate, in profile subelliptic to
obscurely inequilateral, color in water-mounts when fresh dark purple-brown,
in KOH cocoa-brown soon becoming chocolate-gray to dark chocolate-color, in
Melzer's reddish tawny, wall 0.3, thick.
Basidia 4-spored, 20-25 x 7-9 /, clavate with a long narrow pedicel, hyaline
in KOH. Pleurocystidia very abundant, 50-70 x 8-15 /, at first elliptic-pedicellate
in optical section but elongating to subfusoid with obtuse to subcapitate apex
(broadly rounded only in the elliptic state), apex with granular, hyaline debris
often adhering, wall thin and hyaline, content of cell not distinctive in KOH or
Melzer's. Cheilocystidia clavate, saccate or fusoid-ventricose, neck fairly distinct from the ventricose portion (these cells measuring 32-46 x 9-12 p, the clavate
to saccate type up to 30x 16 p and their bases at times slightly yellowish when
revived in KOH).
Pileus with a cuticle formed by a region of inflated hyaline cells several
deep but the cells very irregularly arranged, walls thin, smooth and hyaline,
content not distinctive in KOH or Melzer's. Hyphae of the trama tawny brown
when revived in KOH but gradually fading out to pale tawny brown or ochraceous, walls smooth or at most minutely uneven in a few. Clamp connections