E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Section Calodontes (Smith), Section Luculentae (Maas Geesteranus). Mycena aurantiomarginata is characterized by an olive fuscous to yellowish olive, moist cap, pallid to gray olive gills with bright orange margins, a brownish to grayish olive stem, a white spore deposit, and spiny cystidia. The description is derived from Smith(1) except where noted.

Mycena aurantiomarginata has been found at least in WA, OR, and CA. It was reported from BC by Gamiet(1). Breitenbach(3) give the distribution as North America, Europe, and North Africa.

Cap:
0.8-2cm across, obtusely conic to bell-shaped becoming nearly flat; not hygrophanous, dark olive fuscous to yellowish olive on disc, margin orange shaded with fuscous; lubricous, faintly hoary-pruinose, soon polished, margin striate, becoming somewhat pleated when old

Flesh:
thin, rather pliant

Gills:
adnate or with a decurrent tooth, close, narrow becoming broad when old; pallid to grayish olive with edges bright orange, (Smith), "pale orange when very young, then deep egg yellow or pale greyish yellow, fading to pale beige or pale greyish, towards the base olivaceous yellow or pale sepia grey-brown, the edge convex, bright orange to fairly pale orange-yellow", (Maas Geesteranus)

Stem:
3-6cm x 0.1-0.2(0.3)cm, rigid, cartilaginous, round in cross-section or compressed; "buffy brown" to "medal bronze" [light brownish to olive or grayish olive], sometimes tinged orange; bald except orange powder toward top, base strigose with orange hairs, (Smith), colored somewhat like cap (Trudell)

Odor:
not distinctive

Taste:
not distinctive

Microscopic spores:
spores 7-9 x 4-5 microns, elliptic, smooth, amyloid; basidia 4-spored; pleurocystidia and cheilocystidia abundant and similar, 28-36 x 7-12 microns, clavate to subcapitate [with a head], the tops sparsely or densely echinulate [with small spines], filled with a bright orange pigment

Spore deposit:
whitish cream (Breitenbach)