Summary:
Section Typicae (Smith), Section Filipedes (Maas Geesteranus). Features include 1) small size, 2) a black-brown striate cap that fades to pale gray-brown, 3) adnate, close, white gills that become grayish and may be spotted reddish brown, 4) a cap-colored stem with a white bloom, 5) growth on needle beds or sphagnum, 6) a white spore deposit, and 7) microscopic characters. The description is derived from Maas Geesteranus except where noted.

Cap:
0.8-2cm across, convex or conic becoming flat-convex with "more or less pronouncedly umbonate with the umbo more or less flattened", somewhat hygrophanous, almost black to black-brown when young, when old fading to pale gray-brown, sometimes becoming spotted reddish brown, the margin at first "cinnamon drab" to "drab" (Ridgway(1) colors), fading but remaining slightly cinnamon-tinted; pruinose, becoming bald, "smooth to shallowly sulcate, translucent-striate", (Maas Geesteranus), colors "nearly always possess a tinge of cinnamon, which gives a very characteristic appearance to the dominant dark gray"; surface moist, at first conspicuously hoary, smooth or somewhat rugulose [finely wrinkled], translucent-striate toward margin when moist; margin flaring or recurved when old and often wavy or crenate [scalloped], (Smith)

Flesh:
thin, firm; blackish fading to pallid

Gills:
ascending, adnate, decurrent with a tooth, 17-25 reaching stem, fairly narrow to broader in middle (0.15-0.3cm), sometimes interveined; white becoming gray, sometimes spotted or stained reddish brown, edges pallid, (Maas Geesteranus), "ascending-adnate and with a distinct decurrent tooth, becoming horizontal and shallowly adnexed, close to subdistant", 19-25 reaching the stem, 3 tiers of subgills, narrow to subventricose when old (0.15-0.3cm broad), at times strongly interveined, "pallid grayish to dark gray, sometimes white when young, sometimes staining reddish brown in age or entirely rubescent"; "edges pallid and even", (Smith)

Stem:
3-12cm x 0.1-0.2cm, equal or somewhat widened in lower part, hollow, firm but brittle, straight to somewhat flexuous [wavy]; color as cap, paler toward top, soon fading; finely pruinose becoming bald; "base covered with long, fairly coarse, flexuous, whitish fibrils", (Maas Geesteranus), approximately 2-4cm when growing on needles or about 5-12cm in sphagnum moss, often with abundant clear watery juice from stem when cut [but Maas Geesteranus believes this to be a local or temporary rather than general quality], (Smith)

Odor:
mild or slightly of radish

Taste:
mild or slightly of radish

Microscopic spores:
spores 8.1-9.8 x (4.0)4.7-5.6 microns, pip-shaped, smooth, amyloid; basidia 4-spored, 25-30 x 6.5-8 microns, slender-clavate, clamped, with sterigmata 4.5-5.5 microns long; pleurocystidia not noticed, cheilocystidia 15-45(65) x 7-12.5(22.5) microns, "clavate to more or less irregularly shaped, sometimes very long-stalked, clamped, covered with fairly few to numerous, mostly unevenly spaced, rather coarse, simple to somewhat branched, cylindrical to variously shaped, curved excrescences" 4-11.5 x 0.9-2.5 microns, (Maas Geesteranus), spores 7-9(10) x 3-4(4.5) microns, oval to elliptic, amyloid (reaction weak), (Smith)

Spore deposit:
[presumably white]

Notes:
Mycena atroalboides has been found at least in BC, WA, ID, CA, MI, NY, and TN and as Mycena subplicosa in WA, OR, CA, MI, and NY, (Smith).

EDIBILITY

Synonyms and Alternate Names:
Mycena plicosa sensu A.H. Sm.
Mycena subplicosa sensu A.H. Sm.