North American species of Mycena.

EUMYCENA: CALODONTES

97. MYCENA RUBROMARGINATA (Fr.) Quelet
Champ. Jura et Vosges, p. 435. 1875
Agaricus rubromarginatus Fries, Syst. Myc., 1: 150. 1821.
Illustrations:
Plate 33; Text fig. 23, nos. 1-2 (p. 212).? Bresadola, Icon. Mycol., 5, pl. 222, fig. 1.
Fries, Icon. Sel. Hymen., 1, pl. 78, fig. 4.
Pileus 7-20 mm. broad, obtusely conic to nearly convex, becoming
obtusely campanulate to broadly convex, the margin appressed
against the stipe at first and sometimes flaring slightly at maturity,
surface densely pruinose in buttons, soon naked, moist, color "fuscous" on the disc with a faint tinge of vinaceous at times, soon becoming "chaetura drab" or "hair brown," the margin near "ecru drab"
or paler (dark gray with a vinaceous tinge, soon becoming paler gray,
the disc remaining darker than the margin, sometimes the margin
tinged reddish at first), sometimes very pale when faded; flesh thin,
fragile, watery, grayish to pallid, odor and taste not distinctive;
lamellae ascending but broadly adnate and with only a slight tooth,
moderately broad (3 mm. =-), subdistant, 12-17 reach the stipe, one
or two tiers of shorter individuals, intervenose, pallid to dull grayish
but with bright reddish-brown edges which soon become sordid reddish brown (as seen under a lens); stipe 2-4 (7) cm. long, 1-3.5 mm.
thick, equal, fragile, hollow, terete or compressed, pale watery gray,
translucent, glabrous, base naked or nearly so.
Spores 10-12 X 5-7 1u, broadly ellipsoid, germinating readily (one
often finds germinated spores in a deposit), amyloid; basidia fourspored; pleurocystidia very rare (usually only near the margin),
similar to the cheilocystidia; cheilocystidia 28-42 X 8-12,, broadly
fusoid-ventricose when young, elongating and in age somewhat irregular or narrowly fusoid-ventricose to subcylindric, apices sometimes forked; gill trama homogeneous, of broad hyphae, faintly
vinaceous brown in iodine; pileus trama with a well-differentiated
pellicle and hypoderm, remainder floccose and of broad hyphae, pale
vinaeeous brown in iodine; stipe tissue bright vinaceous in iodine.
Habit, habitat, and distribution.-Scattered on branches of fir and
spruce, either on the naked limbs of dead trees or on the lower dead
branches of living trees, often abundant in slashings. Fairly common
in the fall. In the northern regions it is not uncommon from New
York to Oregon, and is known from British Columbia. In the eastern