The North American species of Psathyrella.

1972]

PSATHYRELLA

211

Habit and habitat. Gregarious on beech logs.
Distribution. Michigan.
Observations. Over one hundred isolated basidia were examined and no sign
of a clamp connection was found, and none were found on the hyphae of the stipe
though one must be careful there not to misinterpret clamplike branches which
do not occur in conjunction with a cross wall. The pale tan outer veil is a good
field character. The spores become nearly hyaline after an hour in KOH. Orton's
description covers the American material remarkably well.
Material examined. Michigan: Smith 993, 25641, 36234.
168. Psathyrella ligulata A. H. Smith, sp. nov.
Pileus 1-3 cm latus, convexus, demum late convexus, copiose fibrillosus demum
squamulosus, (squamulae ligulatae), glabrescens, cinnamomeo-brunneus demum
rugulosus; lamellae latae, confertae, pallidae demum atro-brunneae; stipes 3-8 cm
longus, 1.5-4 mm crassus, cavus, albidus, fibrilloso-squamulosus; sporae 8-10 X
4.5-5.5 /A; pleurocystidia 32-44x8-14 /A, fusoide ventricosa, subacuta; fibulae
adsunt. Typus. Smith 1743 (MICH); legit prope Ann Arbor, Michigan.
Illust. P1. 61, fig. a; Text Figs. 378, 379.
Pileus 1-3 cm broad, convex when young, becoming broadly convex to nearly
plane, surface at first covered by a superficial layer of fibrils which soon become
aggregated into somewhat strap-shaped recurved fibrillose scales and become
worn away by the time the pileus is mature, margin at first fringed or appendiculate with veil-remnants, the fibrils tinged pale buff (paler than "pinkish buff"),
surface of pileus "cinnamon-brown" when fresh and moist, hygrophanous, fading to
light buff, even or radially rugose near the margin when faded. Context fragile,
thin, odor and taste not distinctive.
Lamellae adnate, soon seceding, broad, widest at the stipe, tapered to pileus
margin, close, whitish but soon brownish to avellaneous and finally dark blackish
brown, edges white fimbriate.
Stipe 3-8 cm long, 1.5-4 mm thick, hollow, fragile, cartilaginous, white,
covered by a dense but evanescent coating of recurved pallid buff fibrillose
squamules.
Spores 8-10x 4.5-5.5 I,, smooth, apical pore distinct but apex only obscurely
truncate or not at all so, shape in face view subovate with a pointed apiculate
end, varying to elliptic, in profile subelliptic to obscurely inequilateral, color in
KOH "mummy-brown" (blackish brown), in Melzer's very dark rusty brown (not
reddish), wall about 0.5 / thick.
Basidia 4-spored, 18-22 x 8-9 /u, clavate, hyaline in KOH. Pleurocystidia
scattered to abundant, 32-44 x 8-14 /x, fusoid-ventricose with apex obtuse to subacute, wall smooth, thin and hyaline, cell content not distinctive in KOH or in
Melzer's (no globule observed in water mounts when fresh). Cheilocystidia
similar to pleurocystidia or shorter and more obtuse.
Gill trama regular, the hyphae nearly parallel and hyaline to pallid cinnamon
revived in KOH. Pileus having a cuticle of vesiculose hyaline cells 2-3 deep, the
walls thin, smooth and hyaline, the content of the cells not distinctive. Hyphae
of context interwoven and pale reddish cinnamon to tawny-brown in KOH. Clamp
connections small and inconspicuous but present. No distinctive reaction observed
on any tissue mounted in Melzer's.
Type locality. Ann Arbor, Michigan.
Habit and habitat. Closely gregarious on soil at edge of pine woods, August.