The North American species of Psathyrella.

1972]

PSATHYRELLA

193

recurved, clavate hyphal ends. Hyphae of stipe roughened and with pale cinnamon
deposits in the region of the septa.
Gill trama regular, rusty brown in KOH, the subhymenium cellular and also
rusty brown. Pileus trama floccose, interwoven, dark rusty brown in KOH and
with incrustations on the wall especially near the septa. Cuticle formed by a
single layer of vesiculose cells some of which are pedicellate but they are not
arranged in a distinct palisade. Clamp connections present but rare.
Type locality. Stockbridge, Michigan.
Habit and habitat. Scattered on black muck.
Distribution. Known only from the type locality.
Observations. This is one of the few species where the hyphae of the stipe
show pigment deposits near the septa. This feature, rarity of clamp connections,
and the salmon tint to the faded pileus are distinctive.
151. Psathyrella fatiscens A. H. Smith, sp. nov.
Pileus 1-3 cm latus, obtuse conicus demum planus, sparse squamulosus, glabrescens, ad marginem rimosus, cinnamomeo-brunneus; lamellae confertae, angustae demum latae, sordide cinnamomeae demum vinaceo-brunneae; sporae 9-12 X
5-6 p; pleurocystidia 36-52(-58) x 10-16(-22) /, utriformia vel late fusoideoventricosa, late rotundata; fibulae adsunt. Typus. Smith 67365 (MICH); legit
prope Manchester, Michigan.
Illust. Text Figs. 341-344.
Pileus 1-3 cm broad, obtuse with the margin straight at first, expanding to
plane or with the margin uplifted slightly, with or without a slight umbo, often
splitting along the margin; outer veil white, thin, soon broken into minute
squamules which soon vanish; surface moist and hygrophanous, cinnamon-brown
fading to grayish buff, striate to disc when moist. Context very crumbly and
fragile, thin, concolorous with surface, odor and taste not distinctive, FeS04 no
reaction.
Lamellae close, narrow becoming moderately broad, adnate, pale dull cinnamon becoming cocoa-color and finally dark vinaceous brown; edges even, pallid,
not deliquescing.
Stipe 2-4 cm long, 1-3 mm thick, equal, hollow, exceedingly fragile, whitish
over all at first, darker below when moist but when faded concolorous throughout,
thinly fibrillose from remains of the veil.
Spores 9-12 x 5-6 g, smooth, apical pore small and apex obscurely truncate
(or "pore" bulging out in KOH mounts to form a bubble), shape in face view
elliptic to ovate, in profile obscurely bean-shaped to obscurely inequilateral, color
in KOH dark cocoa-color slowly becoming dark chocolate-color, in Melzer's dark
reddish tawny, wall about 0.5 u/ thick.
Basidia 4-spored, 25-30 x 9-12 gu, clavate, hyaline in KOH. Brachybasidioles
present in age. Pleurocystidia 36-52(-58) x10-16(-22) /u, utriform to fusoidventricose with broadly rounded apex, neck indistinct or well developed but wide,
some cells subcylindric-pedicellate, some subglobose-pedicellate, thin-walled,
smooth, hyaline, cell content not distinctive. Cheilocystidia similar to pleurocystidia but smaller. Caulocystidia versiform (Fig. 341) thin-walled, smooth, cell
content not distinctive.
Gill trama regular, hyphal walls vinaceous-cocoa-color in KOH but fading;
subhymenium cellular. Pileus trama of hyphae vinaceous-cocoa-color in KOH,
with distinct incrustations on the walls. Cuticle of pileus a layer of inflated cells