Lloydia 9: 117. 1946.
Common Name: none
Cap 15-40 mm broad, convex, plano-convex in age, disc occasionally depressed, with or without a shallow umbo; margin incurved, becoming decurved, not striate; surface glabrous, hygrophanous, honey-brown, medium-brown, sometimes with olivaceous tones, fading with drying; context up to 3 mm thick, soft, cream-colored; odor not distinctive; taste mildly astringent.
Gill notched, close, 4-5 mm in width, pale yellow, darker yellow to yellowish-brown in age, edges even, concolorous with faces; lamellulae in 1-2 series.
Stipe 30-70 x 3-7 mm thick, cylindrical, hollow with a yellowish lining; surface pruinose at apex, colored like the cap, darker brown towards base, innately streaked with yellowish-tan fibrils; cream colored mycelium at the base; partial veil absent.
Spores 4-6.5 x 3.5-4 µm, ellipsoid to subglobose, smooth, hilar appendage prominent; spores inamyloid, white in deposit.
Solitary to clustered, typically on rotting conifer logs and debris, rarely with hardwoods; fruiting after fall rains to midwinter; occasional.
This relatively small collybioid-statured mushroom is easily overlooked due to its nondescript color which blends well with the lignicolous substrate on which it grows. The cap is typically yellowish brown to brown cap but sometimes develops olivaceous tones, a character reflected in the species epithet. Yellowish gills, a slender yellowish brown stipe and white spores also help define the species. Similar white spored mushrooms on wood such as Gymnopus species have differently colored caps, gills, and stipes. Simocybe centunculus, also a small lignicolous, brown spored species, has an olivaceous, velvety cap (use hand lens), and occurs on rotting hardwood logs. Other small mushrooms found on rotting wood or moss covered wood such as Galerina and Tubaria species, can be distinguished by their brown spore prints.
Berkeley, M.J. & Curtis, M.A. (1859). Centuries of North American Fungi. Annals and Magazine of Natural History 3(4): 284-296.
Lennox, J.W. (1979). Collybioid genera in the Pacific Northwest. Mycotaxon 9(1): 117-231.
Redhead, S.A. (1982). The systematics of Callistosporium luteo-olivaceum. Sydowia 35: 223-235.
Singer, R. (1946). Type studies on agarics. II. Lloydia 9: 114-131. (PDF)