The North American species of Psathyrella.

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in age the margin uplifted in some, at first covered with more or less granulose
patches of outer veil material but these soon disappearing, margin appendiculate
at first, surface moist and hygrophanous, striatulate nearly to the disc when moist,
watery brown moist, fading to grayish brown. Context very thin and fragile, taste
slight, odor faint (of decaying wood).
Lamellae thin, close, adnate, a delicate cinnamon-brown becoming darker
in age.
Stipe 2.5-4 cm long, 1-2 mm thick, slender, equal or slightly tapering upward,
finely striate, minutely scurfy or mealy at least when young, hollow, white.
Spores 8-12 x 6-7 p (Peck), "8.5-9.3 (-11.5) x 4.7-6 (-6.5) p (Singer), ellipsoid,
rarely somewhat reniform, smooth, brown when seen on lamellae with binocular,
brownish hyaline under oil immersion, without metachromatic (pink) endosporium in cresyl-blue mounts, pseudoamyloid except for the pore region (but weakly
so), with a non-truncate very narrow apical pore which is particularly distinct
in the Melzer solution, without suprahilar depression, with homogeneous epi- and
endosporium.
"Hymenium: Basidia not studied. Cystidia on sides and edges of lamellae
equally numerous, 28-40x 11.5-14.3 I, vesiculose-elongate ventricose, sometimes
with a constriction underneath the apex, always broadly rounded.
"Hyphae: all with clamp connections; hymenophoral trama apparently
regular; all hyphae inamyloid.
Covering layer of pileus: Epicutis of the Psathyrella type, cellular, with
somewhat compressed subisodiametric elements. Stipe with a surface layer consisting of spherocysts (an epithelium)." (quoted material from Singer, 1959).
Type locality. Columbus, Ohio.
Habit and habitat. Gregarious or subcespitose on the ground in a greenhouse,
August.
Distribution. Known only from type locality.
Observations. I have seen no material fresh.
Psathyrella subg. Conocybella Singer, Lilloa 22: 470. 1949.
This subgenus is a continuation, in a sense, of sect. Psathyrella except for the
Conocybe-like cheilocystidia. If an origin of the Coprinaceae from the Bolbitiaceae is accepted, then this group (which includes only the type species) is possibly
a primitive Psathyrella. No matter how one visualizes the phylogeny, the type
species is certainly a good intermediate between the two families.
Type. Psathyrella michiganensis.
398. Psathyrella michiganensis A. H. Smith, Contr. Univ. Mich. Herb. 5: 35. 1941.
Illust. P1. 90a; Text Figs. 862-864.
Pileus 1-2.5 cm broad, obtusely conic and with the margin appressed against
the stipe when young, remaining broadly conic or in age the margin flaring somewhat, surface moist, when young minutely pubescent from projecting hairs, soon
glabrescent opaque when young and moist, only very faintly striate at maturity,
color varying from sordid "tawny-olive" to "bister" or nearly black when the
spores mature, sometimes the disc becoming "wood brown" and the margin "avellaneous," hygrophanous, atomate when faded, fading to dingy ashy brownish or
grayish white, margin regular and not sulcate or folded in age. Context very thin
and fragile, odor none, taste very faintly of radish.
Lamellae ascending adnate, not readily seceding, moderately close (23-27