The North American species of Psathyrella.

1972]

PSATHYRELLA

253

hygrophanous, when young pallid with disc tinged ochraceous, margin becoming
faintly striatulate, gradually becoming avellaneous to wood brown (pale to
dark grayish brown) as spores mature. Context very thin and fragile, odor and
taste mild, very soon riddled by insect larvae.
Lamellae close, narrow, adnate to depressed-adnate, pallid to brownish becoming dark cocoa-color from the spores, edges even.
Stipe short, 1-3 cm long, 2-2.5 (-3) mm thick, equal, hollow, very fragile, white
to whitish, glabrous, not darkening distinctly at the base.
Spores 6.5-7.5 x 3.5-4 t, smooth, apical pore indistinct, shape in face view
ovate to elliptic and many showing a slight angularity, in profile suboblong to
obscurely inequilateral, color in KOH soon dark chocolate-color, in Melzer's
reddish tawny, wall about 0.2 / thick.
Basidia 4-spored, 14-18(-22) x 5-7 K, hyaline, clavate. Pleurocystidia scattered, 28-37(-45) x 9-13, utriform to fusoid-ventricose, with an amorphous
incrustation over apex which slowly dissolves in KOH, thin-walled, reviving
poorly, hyaline and content empty as revived in KOH or Melzer's. Cheilocystidia
similar to the pleurocystidia and incrusted like them. Caulocystidia not present
in any significant number. Hyphae of the stipe cortex with very fine incrusting
material in some areas but hyphal walls not distinctively colored in either KOH
or Melzer's.
Pileus cuticle of inflated cells 1-2 deep, the walls yellowish to hyaline in
KOH, smooth, thin, and many cells of the cuticle projecting somewhat or merely
clavate but with a projecting proliferated apex. Hyphae of subcutis not distinctly colored in KOH or Melzer's. Clamps present. No distinctive reaction
as revived in Melzer's for any tissue.
Type locality. New York.
Habitat and habit. Cespitose at base of hardwood trees, especially sugar
maple, late summer.
Distribution. Michigan and New York.
Observations. This is one of the very few species of Psathyrella which sometimes is readily attacked by insect larvae to the degree of often riddling the
basidiocarps by the time they are mature. In Pholiota veris the same pattern
has been observed. The pallid pileus when young and the very fragile consistency
appear to distinguish it from P. polycephala.
The spores of Peck's type had the cocoa-color to darker reaction in KOH
which clearly indicates the genus Psathyrella. Since the hyphal details of the
type were difficult to ascertain the above description is taken entirely from the
Michigan collections. This description checks well with Peck's original.
Material examined. MICHIGAN: Smith 38229, 81001. NEW YORK:
Peck's Type.
211. Psathyrella polycephala (Fries) A. H. Smith, comb. nov.
Agaricus spadiceus var. polycephalus Fries, Epicr. Syst. Mycol. 226. 1838.
Agaricus polycephalus (Fr.) Leveille, Iconogr. Champs. Paulet, 60. 1855.
Psilocybe spadicea var. polycephala (Fr.) Sacc., Sylloge Fung. 5: 1053. 1887.
Psilocybe polycephala (Fr.) Peck, Bull. N. Y. State Mus. 157: 55. 1912.
Illust. Leveille 1. c. pl. 111, figs. 1, 2. Peck, 1. c. pl. 127, figs. 1-9. P1. 71, figs. a-b.
Pileus 1-3 cm broad, obtuse to broadly convex, the margin inrolled, soon
plane or with a somewhat wavy margin, surface glabrous and moist, even to
rugose-reticulate, margin opaque at first but soon striatulate, occasionally
scalloped, no veil remnants present, hygrophanous "pale pinkish buff" with a
whitish margin, at times darker and "cinnamon-buff" (pale tan or argillaceous)