Mycena citrinomarginata
Description
Mycena citrinomarginata cap color can be anything from pale yellowish to olivaceous to date brown, the gills from whitish to yellow-gray usually with a lemon yellow edge (hence the species epithet), and the stipe a range similar to that of the cap. The fruiting bodies are very dark brown and have sordid-brown gill edges. In the deep shade of conifer thickets, a very pale delicate yellow to whitish form is found.
Distribution is wide and includes under trees in forests and parks, among fallen leaves, in mosses, on rotting tree bark, and in city-dwellers’ lawns.
This is a highly variable species but the yellow shades at the pileus and stipe are good characters, as is also the usually distinctly colored lamellar edge. Another typical feature is the stipe that often is covered with woolly fibrils far up the stipe. These "hairs" are visible in the microscope as long cylindrical cells up to at least 200 µm long.
Common names: Yellow-Edged Mycena.
Mushroom Identification
Cap
10-20 mm broad, obtuse-conic, broadly so in age, sometimes campanulate, often with a low umbo; margin decurved, entire in youth, occasionally becoming crenate to eroded; surface moist, glabrous, hygrophanous, translucent-striate to sulcate-striate to near the disc, the latter with a sparse bloom when young, color brown, yellowish-brown, to yellow, darker at the disc, fading with age; context thin, approximately 1 mm thick, buff to watery brown; odor and taste raphanoid.
Gills
Ascending-adnate to slightly notched, descending the stipe apex a short distance as lines; up to 3 mm broad, pale grayish tan, maturing buff to pale tan, sometimes intervenose in age, edges marginate, pinkish brown, light brown, to yellowish; lamellulae in up to two series.
Stipe
10-40 x 1-1.5 mm thick, fragile, cylindrical, to slightly enlarged at the base, hollow in age, the surface of apex inconspicuously pruinose, striate from gill edges, elsewhere glabrous or with innate fibrils, dingy pinkish-tan, darker towards the base, the latter sparsely covered with soft white hairs; partial veil absent.
Spores
8-12.5 x 4-5.5 µm, ellipsoid, smooth, thin-walled, hilar appendage not conspicuous, amyloid; spores white in deposit.
Habitat
Scattered to gregarious in urban grassy areas, e.g. lawns, cemeteries, etc.; in the grass in montane seepage areas; also in mixed coastal forests and the Sierra Nevada; reported under Sitka spruce (Picea sitchensis), lodgepole pine (Pinus contorta), and white fir (Abies concolor), as well under hardwoods; fruiting after fall rains along the coast and after snowmelt in the Sierra Nevada; occasional to locally common.
Photo sources:
Photo 1 - Author: Arne Aronsen/Naturhistorisk museum, Universitetet i Oslo (CC BY-SA 3.0)