The North American species of Psathyrella.

19721

PSATHYRELLA

359

Observations. Psathyrella ephemera has brachybasidioles but the pileus does
not become plicate-striate, hence it is not referable to the genus Pseudocoprinus.
332. Psathyrella elliptispora A. H. Smith, sp. nov.
Pileus 1.5-3 cm latus, subplanus, glaber fulvo-cinnamomeus; lamellae confertae, latae; stipes 4-5 cm longus, 1-2.5 mm crassus, pallidus, sparse fibrillosus
glabrescens; velum sparsum; sporae 8-11x 5-6 /; pleurocystidia 34-52 x 10-16 p,
fusoideo-ventricosa, ad apicerum rotundata vel obtusata; fibulae adsunt. Typus.
Smith 19563 (MICH); legit prope Rhododendron, Oregon.
Illust. Text Figs. 722-724.
Pileus 1.5-3 cm broad, convex, becoming nearly plane, surface moist, glabrous
except for scattered fibrils near the margin which may be fringed slightly with
veil fibrils at first, dull tawny to cinnamon-brown, hygrophanous and fading to
pallid avellaneous or slightly ochraceous on the disc. Context very thin and fragile,
odor and taste not distinctive.
Lamellae close, moderately broad, broadly adnate, not seceding in drying,
edges even and white-fimbriate.
Stipe 4-5 cm long, 1-2.5 mm thick, equal, hollow, fragile, white, sparsely
fibrillose at first, soon glabrous, whitish to pallid as dried.
Spores 8-11x 5-6,/, smooth, apical pore distinct and apex truncate but not
broadly so, shape in face view broadly elliptic, in profile broadly elliptic to
obscurely inequilateral, color in KOH dull dark cocoa-color becoming chocolatebrown slowly, in Melzer's tawny, wall about 0.3 / thick.
Basidia 4-spored, 18-26 x 9-11 /u, clavate, hyaline, cell content not distinctive
in either KOH or Melzer's. Pleurocystidia scattered, 34-52x10-16 /, fusoidventricose, with rounded to obtuse apex. Cheilocystidia 28-36 x 9-14,, similar in
shape to pleurocystidia or apex merely obtuse; saccate to clavate cells 12-18x
8-12 A also present, hyaline in KOH and thin-walled. Caulocystidia resembling
the pleurocystidia but varying to clavate or vesiculose and 20 pt broad, hyaline
and thin-walled, some small misshapen cells also present.
Gill trama of somewhat interwoven hyphae hyaline to pale rusty brown in
KOH; subhymenium not distinctive. Pileus having a cuticle of inflated cells, some
that are pedicellate intermingled, the layer about 2 cells deep, the walls thin,
smooth and yellowish to hyaline in KOH, cell content not distinctive. Hyphae
of the context dingy rusty brown in subcuticular region, nearly hyaline near the
subhymenium, pigment mostly in the wall. Clamps present.
Type locality. Rhododendron, Clackamas County, Oregon.
Habit and habitat. Scattered on humus under alder (Alnus).
Distribution. Oregon.
Observations. This species could aptly be characterized as a P. obtusata with
very broadly ellipsoid spores and broadly rounded pleurocystidia. Its degree of
variability deserves further study.
Subsect. Lauricolae A. H. Smith, subsect. nov.
Ad truncos, ramulos, etc.; non ad terrai. Typus. Psathyrella lauricola.
The species placed here were found clearly attached to a woody substratum.
For seemingly terrestrial species see the previous series.