The North American species of Psathyrella.

1972]

PSATHYRELLA

201

nificant since the burn was a very old one. In late maturity the basidioles begin
to resemble brachybasidioles by becoming inflated. The dark color of sections
when first revived in KOH is much like that of the group of species around
P. velibrunnescens.
159. Psathyrella latispora A. H. Smith, sp. nov.
Pileus 15-25 mm latus, late convexus, albo-fibrillosus, glabrescens, cinnamomea-brunneus; lamellae latae, confertae triste vinaceo-brunneae; stipes 5-6 cm
longus, 2-3 mm crassus, candidus, sparse fibrillosus, glabrescens; sporae 9-12 x
5.5-7 /u; pleurocystidia 40-65 x 12-18 I, clavata vel ad apicerum cum 1-3 processi; fibulae adsunt. Typus. Potter 8871 (MICH); legit prope Ithaca, Michigan.
Illust. Text Figs. 355-357.
Pileus 15-25 mm broad, convex, broadly so in age, moist and hygrophanous,
surface at first covered with fascicles of fibrils from the remains of a universal
(outer) veil, more or less glabrescent by maturity, pale to dark cinnamon-brown
moist, fading to avellaneous on the margin and tinged cinnamon-buff on the disc.
Context thin and fragile.
Lamellae broad, close, bluntly adnate, dark vinaceous-brown "natal brown"
as dried, edges whitish.
Stipes 5-6 cm long, 2-3 mm thick, equal, fragile, shining white over all and
white when dried, silky, with scattered fibrils from the veil at first but these
vanishing by maturity.
Spores 9-12 x 5.5-7 /, smooth, apical pore present but inconspicuous and the
pore not causing the apex to appear truncate, shape in face view broadly ovate
to elliptic or angular-ovate, in profile broadly and obscurely inequilateral, in cross
section terete or practically so, color in KOH dull cocoa-color, slowly darkening
to bister (about the color of Psilocybe spores in KOH), in Melzer's dull tawny,
wall about 1 / thick.
Basidia 4-spored, 23-28x9-11 I, clavate, hyaline in KOH. Pleurocystidia
scattered, 40-65x 12-18 I/, clavate but narrowed somewhat near apex which is
obtuse or furnished with 1-3 short finger-like processes or knobs, some fusoidventricose with subacute apex, smooth, thin-walled and hyaline in KOH, content
not distinctive. Cheilocystidia saccate to clavate to fusoid-ventricose, smaller
than the pleurocystidia and apex in fusoid-ventricose cells sometimes branched.
Caulocystidia apparently very rare to absent (apex of stipe silky).
Gill trama hyaline to yellowish in KOH. Pileus trama ochraceous to rusty
brown in KOH, the walls roughened or incrusted with pigment. The cuticle an
irregular palisade of ellipsoid and pedicellate-inflated cells intermingled, walls
smooth, thin, and hyaline and cell content not distinctive. Veil hyphae yellowish
in KOH and with some cells having slightly thickened and highly refractive walls.
Clamp connections present.
Type locality. Ithaca, Michigan.
Habit and habitat. Solitary to subcespitose on sticks.
Distribution. Known only from the type locality.
Observations. The spores become a medium-dark chocolate in about an hour
in KOH. The broad spores often obscurely angular in face view, the shining white
stipe and the cystidia having a strong tendency to produce protuberances at or
near the apex, along with the outer veil, characterize this species.