The North American species of Psathyrella.

1972]

PSATHYRELLA

319

289. Psathyrella subhepatica A. H. Smith, sp. nov.
Pileus 1-3 cm latus, conicus, glaber vel ad marginem indistincte fibrillosus,
hepaticolor; contextu fusco-brunneus; lamellae confertae, adnatae, subcinereae
demum fusco-brunneae; sporae 9.3-12.5 x 5.5-6.5(-7.5) A; pleurocystidia 44-70 X
9-15 t, fusoide ventricosa, obtusa vel subacuta; fibulae adsunt. Typus. Smith
6220 (MICH); legit prope Sharon Hollow, Michigan.
Illust. P1. 77, fig. a; Text Figs. 626-629.
Pileus 1-3 cm broad, obtusely conic and remaining obtuse in age, the margin
often flaring, margin appressed against the stipe at first and faintly fibrillose from
the remains of a rudimentary veil, glabrous otherwise, moist, hygrophanous, dark
reddish brown ("liver brown" to "russet") on disc, the extreme margin paler and
near "pinkish buff" (pale tan), fading to pale tawny ("ochraceous-tawny") or the
disc tinged orange, surface sometimes radially rugulose, in age finally becoming
avellaneous or darker, sordid ashy brown. Context dark watery brown, fading
to buff, thin and fragile, odor and taste not distinctive.
Lamellae close, adnate, moderately broad, seceding, pallid grayish brown becoming dark purplish brown, edges even or faintly fimbriate, not becoming pink.
Stipe 4-10 cm long, 1.5-3 mm thick, equal, white, fragile, base mycelioid, lower
portion faintly fibrillose at first, soon glabrous, extreme apex pruinose, sometimes
slightly silky in age.
Spores 9.3-12.5 5.5-6.5(-7.5),u, smooth, apical pore present but apex only
obscurely truncate, shape in face view ovate to elliptic, in profile elliptic to
obscurely inequilateral, color in KOH soon chocolate-gray to medium chocolatecolor, in Melzer's pale tawny, wall about 0.6 / thick.
Basidia 4-spored, 24-30x 10-12 u, clavate, hyaline in KOH. Pleurocystidia
abundant 44-70 x 9-15 /L, elongate fusoid-ventricose, apex obtuse to subacute, wall
thin, smooth and hyaline, cell content in some with refractive debris in the ventricose part as revived in KOH. Cheilocystidia 28-42 x 10-25,/, fusoid-ventricose
but the neck short and apex subacute, relatively few clavate cells present. Caulocystidia in bunches and about like the pleurocystidia but walls more flexuous,
varying to those similar to cheilocystidia and some vesiculose and 10-15,u wide.
Gill trama interwoven, hyaline to sordid pale brownish in water mounts when
fresh or when revived in KOH, the hyphal cells 50 or more, long and 7-14 pt wide.
Pileus trama floccose and of interwoven hyphae bright to dingy pale cinnamonbrown in water mounts when fresh and when revived in KOH darker but color
fading to ochraceous, pigment incrusted on the hyphae especially near or at the
septa. Cuticle a palisade of pear-shaped to clavate cells much as in Conocybe.
Clamps present. No distinctive reaction observed on any tissue mounted in
Melzer's.
Type locality. Sharon Hollow, near Manchester, Washtenaw County, Michigan.
Habit and habitat. Gregarious on wet soil in low woods.
Distribution. Michigan, New York, Oregon, Wyoming.
Observations. The white stipe, thin veil, dark liver brown pileus when young,
flexuous caulocystidia, spores lacking a distinct apical truncation, and absence of
brachybasidioles at maturity appear distinctive.
Material examined. Michigan: Kauffman 6-3-10; Smith 6220 (Type) 18844,
21391, 23475, 26017, 26186, 33836, 34116. New York: House 6-5-17. Oregon:
Smith 24453, 24454. Wyoming: Smith 34548.