The North American species of Psathyrella.

1972]

PSATHYRELLA

181

Stirps Flocculosa
Key to Species of Stirps Flocculosa
1. Spores becoming hyaline or nearly so in KOH (in about a half hour or less). 2
1. Spores remaining dark colored in KOH for longer periods. 3
2. Spores 5-6.5(-7.5) X 3-4.2 u. see 46. P. thiersii.
2. Spores 8-9 X 4.5-5 gu. 137. P. plumigera.
3. Pileus chocolate-color to red-brown at first; known from Cuba. 138. P. flocculosa.
3. Pileus white from appressed fibrils, grayish brown beneath; northern and western
North America. 139. P. canoceps.
137. Psathyrella plumigera (Berkeley & Curtis) A. H. Smith, comb. nov.
Agaricus plumiger Berk. & Curt., Jour. Linn. Soc. 10: 292. 1868.
Psathyra plumigera (Berk. & Curt.) Saccardo, Sylloge Fung. 5: 1069. 1887.
Atylospora plumigera (Berk. & Curt.) Murrill, Mycologia 10: 23. 1918.
Pileus about 1 cm broad, convex becoming plane but with an obtuse umbo,
pubescently striate, brown, covered with white squamules. Context thin and
fragile.
Lamellae broadly adnexed, fuscous.
Stipe about 3 cm long and 1.5-2 mm thick, slender, fragile, fistulose, white and
subpellucid.
Spores 8-9x4.5-5 Ig, smooth, with an obscure apical hyaline pore, pale dull
brown when first revived in KOH but soon becoming hyaline, in Melzer's pale
reddish tawny (at least on what appeared to be the mature spores).
No other microscopic details could be obtained from the dried material
available.
Type locality. Cuba.
Habit and habitat. On sticks in the woods.
Distribution. Cuba.
Observations. About the only feature of taxonomic value obtained from the
study of the type is that the spores are brownish at first when mounted in KOH
but soon lose this color. On this basis an attempt is made to include the species,
but our knowledge of it is not sufficient for an accurate delimitation.
138. Psathyrella flocculosa (Earle) A. H. Smith, comb. nov.
Gymnochilus flocculosus Earle, Inf. An. Estac. Centr. Agron. Cuba 1: 238. 1906.
Hypholoma flocculosum (Earle) Morgan, Jour. Mycol. 14: 65. 1908.
Drosophila flocculosa (Earle) Murrill, Mycologia 10: 64. 1918.
Pileus 2-4 cm broad, convex when expanded, somewhat hygrophanous, at first
somewhat chocolate-color or red-brown, afterward paler, especially when dry,
surface when young covered with scattered woolly tufts but later nearly glabrous,
the margin not striate and finally revolute, veil thin and evanescent. Context thin
and fragile.
Lamellae narrow, close, adnexed, at first pallid, at length purple-brown.
Stipe 2-4 cm long, 2-3 mm thick, rather short, firm, hollow, white, the surface
minutely roughened to scaly.
Spores 8-10 x5-6 gu, smooth, truncated from a well-developed apical pore,
shape in face view broadly elliptic to ovate, in profile subelliptic to obscurely
bean-shaped, color in KOH avellaneous or a darker grayish brown, in Melzer's
reddish tan, wall about 0.3 pu thick.
Basidia 4-spored, hyaline in KOH, 15-20 x 9-10 /i. Pleurocystidia not