The North American species of Psathyrella.

1972]

PSATHYRELLA

207

Pileus cuticle a palisade of clavate to subvesiculose cells with hyaline walls
and content, or base of pedicel with slightly thickened bright rusty brown walls
(in KOH), in Melzer's no distinctive color change observed. Subcuticular region
as revived in KOH with bright fulvous wall thickenings in places giving thin
sections of the tissue a decidedly spotty appearance, the thickenings mostly near
the septa, in Melzer's the color not distinctive. Clamps present.
Type locality. McCall, Idaho.
Habit and habitat. Scattered on wet earth near a stream, September.
Distribution. Known only from the type locality.
Observations. This is a rather distinctive little agaric featuring large readily
collapsing pleurocystidia, decidedly versiform caulocystidia, spores 9-12.5 x
5-6.5 /., and the pileus cuticle a palisade of cells as described. The coarse veil
and dark color of the pileus in contrast to the hyaline grayish stipe also aid in
distinguishing it.
164b. Psathyrella rufogrisea var. bonnerensis A. H. Smith, var. nov.
A typo differt: lignatilis; stipes deorsum demum sordide brunneus, ad apicerum pallidus. Typus. Smith 54189 (MICH); legit prope Priest River, Idaho.
Illust. P1. 59, fig. b.
Pileus 10-15 mm broad, obtusely conic expanding to campanulate, surface at
first covered with superficial squamules composed of white fibrils (but margin not
appendiculate), at maturity glabrous or nearly so, russet to "Mars brown" on the
disc, pale cinnamon-brown toward the margin, when moist closely translucentstriate, hygrophanous and fading to tan on the disc first. Context thin, concolorous
with surface, odor and taste not distinctive.
Lamellae dingy brownish when young, dark grayish cocoa-color in age, close,
broad, ascending-adnate, edges even, not becoming pinkish as far as is known.
Stipe 3-5 cm long, 1-1.5 mm at apex, equal or slightly enlarged downward,
apex pallid, becoming dark dingy brown from the base upward in aging, surface
white-fibrillose at first from the white outer-veil remnants, glabrescent, apical
region pruinose, base slightly radiate-strigose.
Spores 9-12x5.5-6.5 x, smooth, apical pore present but obscure and spore
apex at most only obscurely truncate, in face view elliptic to subovate, in profile
obscurely bean-shaped to elliptic, color in KOH dark cocoa-color, becoming dark
chocolate-color, in Melzer's tawny or slightly more rusty brown; wall about 1 I
thick.
Basidia 4-spored, 10-12 x broad, clavate. Pleurocystidia scattered, 38-60x
12-16 Iu, fusoid-ventricose, with subacute apex, walls thin and smooth, content
"empty" or with scattered refractive granules, no distinctive reaction when
mounted in Melzer's. Cheilocystidia similar to pleurocystidia or shorter and more
obtuse; clavate hyaline cells also present. Caulocystidia subglobose, clavate or
fusoid-ventricose, scattered, size variable, walls thin and hyaline. Hyphae of
cortex with some pigmentation near the septa in lower part of stipe but septa not
appearing as dark bands under the microscope.
Type locality. Priest River Experimental Forest, Priest River, Idaho.
Habit and habitat. On sticks of wood along a stream, October.
Distribution. Known only from the type locality.
Observations. This variant is too similar to P. rufogrisea to be regarded as
a distinct species. It is described here as a variety mainly because it is clearly
on wood rather than moist earth, and the stipe darkens from the base upward.