North American species of Mycena.

310 NORTH AMERICAN SPECIES OF MYCENA

151. MYCENA NIVEIPES Murrill
Mycologia, 8: 221. 1916
Mycena polygramma var. albida Kauffman, Rep. Mich. Acad. Sci., 13: 919.
1916.
Prunulus niveipes Murrill, North Am. Flora, 9: 332. 1916.
Illustrations:
Plates 67-68; Text figs. 37, no. 5 (p. 308); 38, nos. 1-2.
Lange, Flora Agar. Dan., 2, pl. 51 E (short-stemmed form).
Smith, Mycologia, 29, fig. 3 a.
Pileus (1.5) 2-7 cm. broad, ellipsoid when young, convex to
obtusely conic or becoming nearly plane at maturity, the margin appressed against the stipe at first by a narrow sterile band, which soon
becomes lacerated, in age the margin either spreading or slightly recurved, surface smooth, translucent-striate, moist, color "clove
brown" to "olive brown" or sordid drab when young and moist,
hygrophanous, fading to whitish or various shades of sordid grayish
brown on the disc, margin white and sometimes sulcate in age, often
splitting; flesh thin and very fragile, grayish to whitish, taste acidulous
to subfarinaceous, odor either nitrous or entirely lacking; lamellae
ascending-adnate or toothed, close to subdistant (22-35 reach the
stipe), broad (5-8 mm.), white or faintly bluish gray at first, soon
fading to white, in age occasionally flushed with pink, edges even or
slightly fimbriate; stipe 4-10 cm. long, 2.5-7 mm. thick, at times
somewhat radicating, very fragile, equal, hollow, base covered with
white mycelium or somewhat strigose, midportion covered with a
dense white appressed fibrillose coating, soon longitudinally fibrousstriate or in age becoming glabrous, apex somewhat scabrous at first,
pale bluish cinereous when young, becoming either sordid or shining
white.
Spores subglobose to ellipsoid, 8-10 (11) X 5-6 (7) p, amyloid;
basidia two-, three-, or four-spored, 28-30 X 6-7,; cheilocystidia
and pleurocystidia similar and abundant, 50-90 X 8-15 i, smooth,
broad at the base, with subacute to acute apices, those on the gill edge
often shorter (40-60 /) and more nearly fusoid-ventricose; gill trama
yellowish or very faintly vinaceous brown in iodine; pileus trama with
a well-developed pellicle, a distinct hypoderm, and the remainder
filamentous, yellowish in iodine.
Habit, habitat, and distribution.-Single to gregarious or sub