The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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standing. Cuticle of pileus a layer of inflated cells 2-4 deep with dingy ochraceous
smooth walls (in KOH) which are somewhat refractive (but not gelatinous).
Subcuticular hyphae weakly incrusted and pale fulvous in KOH. Clamps present.
Type locality. Herman-Silver River area, Baraga County, Michigan.
Habit and habitat. Cespitose to gregarious on soil in logging roads about a
year old, June.
Distribution. Known only from the type locality.
Observations. This species was found fruiting by the hundreds of basidiocarps.
No pseudorhiza was present. The veil is not compactly enough developed to place
the species in the subgenus Pannucia. The distinguishing features of the species
are spore size and color, and the wide range of variation in the shape of the
cystidia. It is close to P. microsperma but has larger spores.
352. Psathyrella heterocystis A. H. Smith, sp. nov.
Pileus 7-30 mm latus, conicus vel campanulatus, glaber, fulvus; oder subgraveolens; sapor leviter raphanicus; lamellae subdistantes vel distantes, pallidae
demum subfuscae (griseo-brunneae) latae; stipes 2-5 cm longus, 1.5-3 mm crassus, pallidus, deorsum demum sordide brunneus, glabrescens; velum sparsum;
sporae 7-9 (-10) x 4-5 z; pleurocystidia 3647 x 10-16 I,, utriformia, vel 35-50x
6-20 t, fusoide ventricosa, ad apicerum rotundata, vel 40-70x9-12 /, anguste
fusoideo-ventricosa; cheilocystidia 20-35 x9-25 /, subfusoidea, flexuosa et subacuta, interdum subcrassotunicata; fibulae adsunt. Typus. Ammirati 3310
(MICH); legit prope Herman-Silver River, Baraga County, Michigan.
Pileus 7-30 mm broad, cylindric to conic at first and with an appressed margin,
becoming obtusely conic to campanulate with (finally) the margin flaring, surface
at first with a slight fringe of fibrils along the margin, soon becoming glabrous,
moist and hygrophanous, rusty brown on disc at first and paler ochraceous-brown
toward the margin, in age watery brown and then translucent-striate, pale dingy
buff when faded. Context thin and fragile, whitish to pallid watery brownish
(concolorous with surface), odor "fragrant-fungoid" (Ammirati), taste slightly
raphanoid.
Lamellae subdistant to distant when mature, pallid then grayish pallid to
brownish, grayish brown when mature, broad, moderately thick, ventricose,
ascending-adnexed; edges pallid.
Stipe 2-5 cm long, 1.5-3 mm thick, more or less equal to the slightly bulbous
base, white to pallid at first but soon watery brownish lower down, finely pruinose
above, lower down slightly fibrillose from the rudimentary veil.
Spores 7-9(-10) x4-5 /, smooth, no apical pore evident and spore apex not
truncate; shape in face view elliptic to subovate (some elongate and variable in
shape-angular to narrowly ovate or wedge-shaped), in profile somewhat beanshaped to obscurely inequilateral, color in KOH dingy cocoa-color becoming a
medium chocolate-gray, in Melzer's tawny, wall about 0.2-0.3 pt thick.
Basidia 4-spored, 18-26x8-11 u, clavate, hyaline. Pleurocystidia: (1) 36 -47 x 10-16 /, utriform and with granular debris over the apex (rare); (2) 35-50 x
10-20 Ju broadly fusoid-ventricose with rounded apex and also with adhering
granular debris (fairly common); (3) 40-70 x 9-12 /, narrowly fusoid-ventricose
with obtuse to subacute apex also with adhering debris (common); (4) 40-60x
9-18 p and subfusoid with flexuous walls and apex subacute to rounded and with
adhering material or smooth (common), walls thin or slightly thickened in any
of above types and all hyaline in KOH (one clavate cell with yellow wall