The North American species of Psathyrella.

1972]

PSATHYRELLA

435

as in P. spadicea), glabrous (veil none). Context pallid to dingy brownish,
cartilaginous, odor and taste not recorded.
Lamellae pallid to brownish to cocoa-color and drying dull vinaceous brown,
at maturity broad and subdistant, edges becoming somewhat eroded, adnate, in
age seceding.
Stipe 3-7 cm long, 3-8 mm thick, equal or nearly so, slightly pruinose, white to
pallid, discoloring over the basal region, veil none.
Spore deposit (air-dried) cocoa-color; spores 8-9.5 x 5-6 [, smooth, germ pore
not clearly defined, wall 0.2, thick (~), shape in face view broadly ellipsoid to
ovate, in profile slightly bean-shaped to subelliptic, in KOH with a tinge of
vinaceous brown but subhyaline and not darkening.
Basidia 7-9 p broad, 4-spored. Pleurocystidia abundant, 38-65 x10-18 u,
fusoid-ventricose to broadly ventricose, of 2 types: (1) leptocystidia with smooth
walls and with or without some apical incrusting material, and a homogeneous
content or containing scattered refractive particles; (2) lamprocystidia with
heavily incrusted apex and walls up to 2.5 1, thick, often with an opaque amorphous refractive subgranular content often completely filling the cell. Cheilocystidia clavate (mostly) to fusoid-ventricose, thin-walled, smooth, content
homogeneous, or resembling the lamprocystidia of the gill faces. Caulocystidia
clavate, elongate-clavate, subutriform, fusoid-ventricose with obtuse to rounded
apex and up to 70 x 18,a, thin-walled, smooth, content not distinctive, rarely with
slightly thickened refractive walls in upper portion.
Pileus cuticle a layer of inflated cells 2-4 deep, their walls refractive in KOH,
smooth and not distinctively colored; subeuticular region of inflated hyphal cells,
not distinctively colored in KOH, the walls smooth, thin, and buffy-pallid in
KOH. Clamps presents.
Habit, habitat and distribution. Subcespitose around aspen, Juniper Mountain, Owyhee County, Idaho, June 9, 1971, E. & T. Trueblood 4485.
Observations. The spores from a deposit when mounted in KOH are pale
cocoa-color and in this respect the species is intermediate between sections
Homophron and Cystidiosae. The content of the pleurocystidia resembles that of
"pseudocystidia." In some pilei nearly all pleurocystidia show it but in others
some (even many) pleurocystidia lack it or the cell is only partly filled with the
granules. Both thick- and thin-walled "lamprocystidia" are present, and both
were seen with the granular content. The wide spores and broad subdistant gills
distinguish the species from P. littenii and P. variata. P. rhodospora lacks a distinctive content in the pleurocystidia, but has spores about the same size.
409. Psathyrella rhodospora Weaver & A. H. Smith, sp. nov.
Pileus 3-9.5 cm latus, convexus demum late convexus, glaber demum rugulosus,
pallidus vel pallide alutaceus; lamellae 3-8 mm latae, secedentes, confertae, pallidae demum lateritiae; stipes 3-10 cm longus, 3-15 mm crassus, furfuraceus,
subalbidus, tactu ad basin vinaceo-purpureus; sporae in cumulo lateritiae, 9-11 x
4.5-6,; basidia tetraspora; pleurocystidia 43-56 x 13-17 /, late fusoidea interdum
ad apicerum incrustata, demum crassotunicata. Typus. Weaver 2204 (MICH).
Pileus 3-9.5 cm broad, convex with an incurved margin, becoming broadly
convex or nearly plane, the margin often remaining decurved, shape at times
irregular from mutual pressure; surface glabrous (slightly micaceous under a
lens), smooth to rugulose, margin in some faintly sulcate; pallid to buff (faded)
drying pale dull cinnamon but most of surface dull brick red from spores,