The North American species of Psathyrella.

1972]

PSATHYRELLA

307

dried, veil rudimentary and all traces along the margin soon vanishing. Context
thin fragile, rusty brown moist, cinnamon-buff faded, odor none, taste not
recorded.
Lamellae moderately close, ascending-adnate but broadly attached, broad,
brownish when young, becoming near "benzo brown" (fuscous-violaceous) at
maturity or retaining a more reddish tinge; edges even, pallid not pinkish in age.
Stipe 3-5 cm long, about 1 mm thick, equal, fragile, tubular, pallid at first but
in age brownish over the lower portion though not discoloring markedly.
Spores 10-12.5x 5-6.5 xu, smooth, apical pore present and apex appearing
somewhat truncate, shape in face view elliptic to ovate, in profile obscurely
inequilateral to elliptic, color in KOH soon dark chocolate-color, in Melzer's
tawny reddish, wall about 1, thick (revived in KOH).
Basidia 4-spored, 22-27x9-14 I/, clavate, hyaline in KOH. Pleurocystidia
34-50 x 9-16 /i, ventricose-rostrate to fusoid-ventricose, the neck narrow (2-3 i)
and the apex very acute, wall hyaline, smooth and thin, cell content not distinctive in KOH or Melzer's. Cheilocystidia similar to pleurocystidia along with
vesiculose cells, hyaline to yellowish as revived in KOH. Caulocystidia versiform:
vesiculose-pedicellate and up to 30 Iu broad; clavate to ovate or elliptic (in optical
section) and up to 100 x 25 Iu; fusoid-ventricose with obtuse to rounded apex and
36-60x9-16 ux; or resembling the pleurocystidia, all types thin-walled, smooth
and hyaline, lacking any distinctive content.
Gill trama vinaceous-brown as revived in KOH but gradually fading to cocoacinnamon, pigment in the wall. Pileus trama dark vinaceous-brown becoming
dark cocoa-color, the pigment in the wall or encrusted on it in patches or zones
giving sections a spotted appearance. Cuticle of pileus a staggered series of
clavate-pedicellate cells and vesiculose cells in somewhat of a palisade, the pedicels of the cells often with colored walls in KOH. Clamps present. No distinctive
reactions noted on any tissue in Melzer's.
Type locality. Dexter, Michigan.
Habit and habitat. Gregarious on chip-dirt.
Distribution. Michigan.
Observations. The distinguishing features of this species are the medium large
very dark colored spores, sharply conic pileus, deep pigmentation of the hyphae
of the subcuticular region in the pileus, the very pointed pleurocystidia with their
narrow necks, and the tremendously variable caulocystidia along with at most a
rudimentary veil.
276. Psathyrella rainierensis A. H. Smith, sp. nov.
Pileus 5-10 mm latus, convexus, glaber, lubricus, ad marginem minute floccosus glabrescens, castaneus; contextu fusco-brunneus; lamellae latae, subdistantes brunneolae demum atro-brunneae; stipes 10-15 mm longus, circa 1 mm
crassus, pallide cinnamomeus; sparse fibrillosus; sporae 9-11(-12.5) x5-6.5 Ix;
pleurocystidia 28-37 x (9-) 10-15 ux, late fusoideo-ventricosa, obtusa vel subacuta;
fibulae adsunt. Typus. Smith 30929 (MICH); legit prope Van Trump Park,
Mt. Rainier National Park, Washington.
Illust. Text Fig. 588.
Pileus 5-10 mm broad, convex, expanding to broadly convex, glabrous and
lubricous, with minute flecks of fibrils along the margin from the thin whitish
veil, moist and hygrophanous, "chestnut" to "russet" (dark rich rusty brown)
when moist, fading finally to near "cinnamon-buff" (pale tan) before the