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Gymnopus semihirtipes

[ Basidiomycetes > Agaricales > Marasmiaceae > Gymnopus . . . ]

by Michael Kuo

Gymnopus semihirtipes is a common springtime and early summer litter-decomposer in the Midwest and eastern North America, recognized by its small size, the soon-pale cap, and the reddish brown stem, which is fuzzy over the lower portion (thus the epithet semi-hir-tipes, which means "partly-hairy-stemmed"). By maturity the species usually demonstrates a marked contrast between the dark stem and the pale cap. A drop of ammonia or KOH on the cap or stem surface produces a green or black reaction. Under the microscope, cells from the stem feature dark brown encrustations.

The very similar Gymnopus spongiosus appears in late summer and fall, is slightly larger, features close or crowded (rather than nearly distant) gills, and has a stem that features fuzziness from the bottom nearly all the way to the apex. Under the microscope, cells from its stem lack dark brown encrustations.

Description:

Ecology: Saprobic; growing alone, scattered, gregariously, or in clusters on leaf litter and woody debris under hardwoods; spring and early summer; widely distributed east of the Great Plains.

Cap: 0.5-2 cm; convex, becoming broadly convex or nearly flat; dry; bald; sometimes becoming wrinkled over the center; orangish brown to reddish brown when young and fresh, but quickly fading to pinkish tan or buff, with a darker center.

Gills: Attached to the stem or nearly free from it; nearly distant; whitish.

Stem: 2-5 cm long; up to about 3 mm thick at the apex; more or less equal; dry; densely hairy over roughly the lower 1/3 with reddish brown to purplish brown hairs, but bald above; reddish brown.

Flesh: Whitish; thin; tough.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia or KOH promptly olive, green, or black on cap and stem surfaces.

Spore Print: White.

Microscopic Features: Spores: 7.5-9 x 3-4.5 µ; smooth; lacrymoid to elliptical; inamyloid. Pleurocystidia absent. Cheilocystidia rare or absent. Pileipellis a tangled cutis of cylindric elements 4-11 µ wide. Hyphae of the stem encrusted with dark brown material in a water mount.

Collybia semihirtipes is a synonym.

REFERENCES: (Peck, 1873) Halling, 1997. (Saccardo, 1887; Halling, 1981; Halling, 1983; Halling, 2004.) Herb. Kuo 05089502, 05030401, 05160401, 05030604, 04270704, 05100801.

Further Online Information:

Gymnopus semihirtipes at Roy Halling's Collybia site

 

Gymnopus semihirtipes

Gymnopus semihirtipes

Gymnopus semihirtipes

Gymnopus semihirtipes
KOH

Gymnopus semihirtipes
Hyphae from stem



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Cite this page as:

Kuo, M. (2013, January). Gymnopus semihirtipes. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/gymnopus_semihirtipes.html