North American species of Mycena.

EUMYCENA: TYPICAE

315

Prunulus vexans Murrill, North Am. Flora, 9: 329. 1916.
Illustrations:
Plates 70-71; Text figs. 38, nos. 3-4 (p. 311), 39, nos. 1-2 (p. 316).
Bresadola, Icon. Mycol., 5, pl. 242.
Fries, Icon. Sel. Hymen., 1, pl. 81, fig. 3.
Konrad et Maublanc, Icon. Sel. Fung., 3, pl. 232.
Lange, Flora Agar. Dan., 2, pl. 51, fig. H (very good).
Ricken, Die Blatterpilze, 2, pl. 110, fig. 4.
Pileus (0.5) 1-3 (4) cm. broad, (0.5) 1-3 cm. high, evenly and
obtusely conic, the margin usually flaring somewhat at maturity,
sometimes convex or with a broad obtuse umbo, small forms often
conic-campanulate or papillate, color "bone brown" to "plumbeous
black" when young, "dusky brown" to "pale drab gray" at maturity
or dull brownish, "Saccardo's umber" to "snuff brown" (blackish at
first, becoming very sordid yellowish brown or drab gray in age), the
margin frequently whitish or pallid, surface at first evenly covered
with a conspicuous bloom, giving it a bluish-gray cast or a glaucous
sheen, soon polished and then lubricous, subhygrophanous, obscurely
striate when young, striate to the disc at maturity, the margin sometimes slightly sulcate; flesh thin or moderately thick under the disc,
fragile but cartilaginous, white or grayish, odor strongly alkaline,
sometimes lacking, taste acidulous but hardly distinctive; lamellae
moderately close to subdistant (20-27 reach the stipe), adnate or
with a slight-decurrent tooth, narrow to moderately broad (2-3.5
mm.), pure white or grayish at first, remaining white or becoming
cinereous, sometimes spotted with sordid reddish-brown stains in
age, intervenose at times, edges concolorous with the surfaces or
remaining white; stipe (1.5) 4-9 (11) cm. long, (1) 1.5-2.5 (4) mm.
thick, concolorous with the pileus or paler, especially at the apex,
and often sordid yellowish brown in age, covered with a bloom and
appearing bluish at first, soon polished and lubricous, not viscid,
tubular to hollow, often compressed in large specimens, cartilaginous
and brittle, base sparsely white-mycelioid to strigose.
Spores (7.5) 8-10 (11) X 4.5-6 (7) a, ellipsoid to broadly ellipsoid, smooth, distinctly amyloid; basidia usually four-spored, twospored forms occasionally abundant; pleurocystidia numerous, scattered or rare, sometimes apparently absent, fusoid-ventricose to
subeylihdric, the apices sometimes forked, hyaline, smooth, (35) 40-60
X 8-15 (20) #; cheilocystidia abundant, hyaline, subelavate with an