The North American species of Psathyrella.

1972]

PSATHYRELLA

105

scattered in clusters, similar to pleurocystidia but often up to 100 p long and
with a merely obtuse apex.
Gill trama regular, the hyphae somewhat interwoven, the cells enlarged and
hyaline to dark dingy purplish gray (pale fuscous) to dull brownish in KOH,
with wall thickenings and some incrustation-especially near the septa. Pileus
with a cuticle of vesiculose cells 1-2 cells deep, the walls thin, smooth and hyaline,
the content not distinctive in KOH or Melzer's. Hyphae of the context colored
about like the gill trama and with the local wall thickenings and pigment deposits
near the septa, some hyphae with spiral or bandlike incrustations. Clamp connections present. No distinctive reaction on any part in mounts made in Melzer's.
Type locality. Ann Arbor, Michigan.
Habit and habitat. Scattered on freshly spaded garden soil.
Distribution. Michigan.
Observations. The bright pink gills and clearly terrestrial habitat along
with the small size distinguish this from the type form, but the two are similar
in pigmentation as observed on dried material sectioned and mounted in KOH,
in spore features, and in cystidia. P. barlae f. barlae very likely has caulocystidia.
Material examined. Colorado: Smith 51648. Michigan: Potter 4705, 4909,
4911, 5211, 5212, 7162, 7230, 7247, 7303, 7304, 7308, 7313, 7328, 7329, 7335, 7337,
7338, 7341; Smith 1389 (Type), 20455.
63. Psathyrella hortensis A. H. Smith, sp. nov.
Pileus (2-) 3-3.5 cm latus, conicus demum campanulatus, glaber, ad marginem
appendiculatus, vinaceo-brunneus, sublubricus; lamellae 2.5-3.5 mm latae, avellaneae demum vinaceo-brunneae; stipes 8-11 cm longus, 3-6 mm crassus, cavus
albus, glaber, deorsum fibrillosus; sporae 12.2-15 x 5.5-6.5 /; pleurocystidia 60 -90x 11-15 u, fusoide ventricosa, ad apicerum acuta vel obtusa; fibulae adsunt.
Typus. Smith 2143 (MICH); legit prope Ann Arbor, Michigan.
Illust. Text Figs. 160-162.
Pileus (2-) 3-3.5 cm broad, obtusely conic to convex, becoming broadly obtuse
to plano-umbonate, umbo obtuse, surface glabrous except for the margin which
is at first hung with patches of the whitish submembranous veil, moist and
hygrophanous, exactly "walnut brown" moist, paler pecan buff to near avellaneous
when faded, margins becoming paler when pileus is still moist, surface slightly
lubricous when wet. Context more or less concolorous with pileus surface, thin,
watery, fragile, odor and taste not distinctive.
Lamellae close, 2-3 tiers of lamellulae, one tier almost touching the stipe,
depressed-adnate, horizontal, narrow to moderately broad (2.5-3.5 mm) "avellaneous" young, becoming wood brown to "army brown" (vinaceous brown)
finally, in age even darker but paler again in drying, edges even.
Stipe 8-11 cm long, 3-6 mm thick, equal, hollow, rather firm, white, glabrous
and silky above, white-fibrillose striate below and often with lacerate patches of
veil remnants unevenly distributed, cortex pale sordid watery buff, base white
strigose and many radiating hairs present but a typical pseudorhiza not constantly present.
Spores near "benzo brown" in deposit (with a redder tinge on loss of moisture),
12.2-15 x 5.5-6.5 j/, smooth, apex truncate from a wide apical pore which is rather
inconspicuous, shape in face view elliptic to narrowly ovate, in profile weakly
bean-shaped to obscurely inequilateral with the majority subelliptic, dark reddish
in H20 mounts when fresh, soon bister then a medium chocolate-color in KOH,
in Melzer's bay-red, wall about 0.8 ~ thick.