Collybiopsis subpruinosa
Mycotaxon 136(2): 344. 2021.
Common Name: none
Synonyms: Marasmiellus subpruinosus (Murrrill) J.S. Oliveira; Collybia subpruinosa (Murrill) Dennis; Marasmius subpruinosus Murrill
Cap 1.5-4.0 cm broad, convex, expanding to nearly plane, sometimes with a low umbo; margin at first decurved, plane to slightly upturned in age; surface striate-rugulose, innately fibrillose, and when viewed with a hand lens, minutely pruinose; disc color in young material, chestnut-brown to dingy reddish-brown, elsewhere medium brown, occasionally tinged purplish-brown, hygrophanous, soon light-brown overall except for ribbed areas; flesh thin, less than 1 mm, up to 2 mm thick at the disc, cream-buff, unchanging or sometimes reddish where cut or bruised; odor and taste not distinctive.
Gills adnate to adnexed, subdistant, relatively narrow, dingy-buff, edges pruinose (use hand lens); lamellulae up to three-seried.
Stipe 2.0-5.0 cm long, 1.0-3.0 mm thick, straight, pliant, hollow to stuffed at maturity, equal to enlarged at the apex; surface longitudinally striate, cream-buff at the apex, dark-brown at base, overlain with a buff-colored pubescence; partial veil absent.
Spores 7.5-9 x 3.5-4 µm, ellipsoid to tear-shaped, smooth, thin-walled, inamyloid; spore print white.
Scattered to clustered on humus-rich soils, woody debris and logs; fruiting in late summer in watered areas and after the fall rains.
Unknown, insignificant.
This small drab mushroom is recognized by a brown soon fading to tan cap which is striate-rugulose from margin to disc, an inconspicuously pubescent, slender stipe, and gills with pruinose edges. A related species, Collybiopsis villosipes, abundant on conifer duff, is distingushed by a cap that is striate-rugulose only halfway to the disc, a more densely pubescent stipe, and gill edges which are lighter than the faces. Additionally, Collybiopsis villosipes though similar in size has a thicker stipe relative to the cap, and a disc that tends to be depressed or umbillicate rather than slightly umbonate as in Collybiopsis subpruinos.
Marasmius subpruinosus was transfered to the genus Marasmiellus by J.S. Oliveira in 2019 based on molecular data (see Oliveira et al. Mycological Research, 18-5) and then in 2021 to the genus Collybiopsis based on nomencatural priority (see Petersen & Hughes).
Desjardin, D.E., Halling, R.E. & Hemmes, D.E. (1999). Agaricales of the Hawaiian Islands. 5. The genera Rhodocollybia and Gymnopus. Mycologia 91(1): 166-176.
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Murrill, W.A. & Burlingham, G.S. (1915). (Agaricales) Polyporaceae-Agaricaceae. North American Flora 9(4): 201-296. (Protologue)
Oliveira, J.J.S., Vargas-Isla, R., Cabral, T.S., Rodrigues, D.P. & Ishikawa, N.K. (2019). Progress on the phylogeny of the Omphalotaceae: Gymnopus s. str., Marasmiellus s. str., Paragymnopus gen. nov. and Pusillomyces gen. nov. Mycological Progress 18(5): 713-739.
Petersen, R.H. & Hughes, K.W. (2021). Collybiopsis and its type species, Co. ramealis. Mycotaxon 136(2): 263-349. (PDF)
Siegel, N. & Schwarz, C. (2016). Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.
