The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Observations. The distinctive features of this species are the variable shape
of the pleurocystidia, medium small spores, more or less radicating stipe and
appendiculate margin of the pileus when young. It appears to be related to
P. multipedata but the cystidia are different, and the pileus is more conic as well
as thinner. Also, P. subradicata has an appendiculate veil.
98. Psathyrella lubrica A. H. Smith, sp. nov.
Pileus 2-4 cm latus, obtuse conicus demum late conicus vel plano-umbonatus,
lubricus, nitens, ad marginem subappendiculatus, spadiceus vel cinnamomeobrunneus, sapor subamarus; lamellae confertae, pallidae demum purpureo-fuscae;
stipes 4-5 cm longus, 3-5 mm crassus, albidus, deorsum floccosus, glabrescens;
sporae 7-9 x 3.5-4.8 t; pleurocystidia 46-60 x 9-16 /, fusoide ventricosa, ad apicerum obtusa vel late rotundata; fibulae adsunt. Typus. Smith 15019 (MICH);
legit prope New Hudson, Michigan.
Illust. P1. 48; Text Figs. 243-246.
Pileus 2-4 cm broad, obtusely conic to convex, becoming broadly conic to
nearly plane or retaining an obtuse umbo, margin distinctly inrolled at first
and when expanded becoming plicate to crenate, the surface polished and lubricous, often radially wrinkled to rugulose, margin at first fringed with fibrils
but soon glabrous, opaque at first but becoming striatulate before fading, color
evenly "Prout's brown" to "cinnamon-brown" over all (rust-brown), hygrophanous, slowly fading to pale alutaceous. Context thick in the disc, thin toward the
margin, pallid watery brown fading to buff, odor none, taste mild but with a
bitterish aftertaste.
Lamellae close to crowded, 37-42 reach the stipe, 1-3 tiers of lamellulae,
more or less horizontally adnate, readily seceding, "tilleul buff" young, soon
"avellaneous" to "wood brown," finally purplish brown and dull vinaceousbrown as dried, edges even.
Stipe 4-5 cm long, 3-5 mm thick, hollow, only moderately fragile, equal, white
to whitish, at first with scattered appressed patches of fibrils, glabrous in age.
Spores 7-9 x 3.5-4.6 A, smooth, apical pore distinct and apex truncate, shape
in face view oblong to slightly ovate (obscurely wedge-shaped in some), in profile
subelliptic to obscurely inequilateral, color in KOH dull cocoa-color becoming
a medium dark chocolate on standing, in Melzer's reddish tawny, wall about
0.2 / thick.
Basidia 4-spored, 18-22 x 7-9 I, clavate to narrowly clavate, hyaline in KOH.
Pleurocystidia abundant, 46-60x9-16 P, broadly fusoid-ventricose and tapered
gradually to an obtuse to rounded apex, thin-walled, hyaline, smooth, cell content not distinctive in either KOH or Melzer's. Cheilocystidia mostly clavate to
saccate, the latter 24-32 x 9-15 /, hyaline, thin-walled; the former 30-42 x 9-14 j,
otherwise about like the pleurocystidia. Caulocystidia resembling the pleurocystidia and varying to clavate, mostly as the end-cells of narrow (veil?) hyphae.
Gill trama of more or less parallel elongated hyphae, pallid brownish in KOH
as revived; subhymenium thin and not distinctive, the hyphae very compactly
interwoven and the cells not appreciably inflated. Pileus having a cuticle of
hyaline inflated, smooth, thin-walled cells about 2 deep, some with pedicels,
content not distinctive. Hyphae of the trama interwoven, dark rusty brown to
tawny in KOH, walls smooth or nearly so. Clamp connections present. No
distinctive color reactions on any tissue when revived in Melzer's.
Type locality. New Hudson, Michigan.