The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

appearing moist but opaque beneath a conspicuous coating of innate seal-brown
or "bister" (dark brown) fibrils or somewhat recurved fibrillose scales over the
disc, ground color dull "ochraceous-tawny" (pale dull tawny) on the disc, and
"cinnamon-buff" (pale alutaceous) along the margin, the fibrils over the marginal
area long and appressed giving it a hairy appearance, surface somewhat uneven
to rugulose. Context thick but brittle, "pinkish buff" (pale buff) or darker,
becoming pallid but not distinctly hygrophanous, odor and taste slightly disagreeable (like that of most species of Clitocybe), where touched with FeSO,
olivaceous; with KOH instantly "Mars brown" (dark rusty brown).
Lamellae bluntly adnate, seceding readily, broad (about 1 cm), broadest near
the stipe and narrowed to the pilear margin, close, 50-56 reach the stipe, 3-4
tiers of lamellulae, pallid brownish at first, at maturity deep reddish to purplish
brown ("Carob brown" to "chestnut-brown"), the edges conspicuously whitefimbriate.
Stipe 8-12 cm long, 10-15 mm thick at apex, equal or slightly enlarged
downward, becoming hollow, rather fleshy but brittle, pallid to cinnamon-buff
within, surface "pinkish buff" (pale alutaceous) and the lower two-thirds
covered with coarse seal-brown fibrils from the veil, upper portion pruinose, base
surrounded by white cottony mycelium.
Spores 7-9 x 4-5 a, smooth to very obscurely warty in some, apical pore well
developed and often terminating a rudimentary "snout," shape in face view subelliptic to ovate, in profile somewhat to distinctly inequilateral, color in KOH
soon a medium dark-chocolate color, in Melzer's bay-brown to bay-red, wall
about 0.3 pu thick.
Basidia 4-spored, 20-28x 7-10 f%, clavate, hyaline in KOH or some of them
pale brownish at the base. Pleurocystidia 40-70x 9-18 pa, scattered to abundant
and often fasciculate, subcylindric with rounded apex to utriform, wall thin and
smooth, hyaline, content not distinctive in either KOH or Melzer's. Cheilocystidia
abundant, 60-80 x 9-12 /, narrowly clavate but soon cylindric with wavy outlines
and rounded apex, walls thin, hyaline and smooth in KOH, content in KOH or
Melzer's not distinctive. Caulocystidia resembling the cheilocystidia but more
versiform: filamentous, utriform or obtusely and narrowly fusoid-ventricose,
present only near the apex of the stipe.
Gill trama regular, the hyphae parallel and sordid pale yellowish to pale
dingy cinnamon-brown in KOH, the subhymenium darker. Pileus with a cuticle
of inflated cells several deep, their walls dingy brownish ochraceous in KOH, and
beneath this hyphae with smooth dingy ochraceous-cinnamon walls (as seen in
groups). Context hyphae dingy ochraceous in KOH from colored walls, smooth.
Clamp connections present.
Type locality. Ithaca, New York.
Habit and habitat. In groups of 2-6 basidiocarps near or beside stumps or old
roots of hardwoods, fall, rather frequent locally during wet periods in late
summer.
Distribution. California, Idaho, Maryland, Michigan, Minnesota, New York,
Ohio, Oregon, Washington.
Observations. Spore size is a problem in this species. The type and the
author's Michigan collections have spores as described above, but Potter, near
Ithaca, Michigan, found a variant with spores 8-10 x 5-6 /. A single basidiocarp
from the headquarters area of the Priest River Experimental Forest near Priest
Lake, Idaho has spores 6-7.5 x 3.5-4.5 pu. This situation requires further study.
The distinctive features of the species are the coarse dark brown fibrils of the