Trans. Br. mycol. Soc. 43(2): 176. 1960.
Common Name: none
Synonym: Gymnopilus spectabilis (Fr.) A.H. Smith
Cap 7-20 cm broad, convex with incurved margin, nearly plane in age; surface dry, yellowish-orange to orange with fine brown scales; flesh thick, yellow, turning red in KOH; odor mild to pungent, taste bitter.
Gills close, adnate, notched, to slightly decurrent; yellow, becoming orange.
Stipe 7-21 cm long, 1-4 cm thick, yellow-orange, lighter than the cap, streaked with brown fibrils, equal, club-shaped, or ventricose, usually narrowed at the base; partial veil membranous, yellowish, forming a usually persistent superior ring.
Spores 7.5-10 x 4.5-6 µm, roughened, elliptical. Spore print rusty-orange.
Fruiting from early fall to mid-winter in clusters on stumps and logs of both hardwoods and conifers.
Inedible, very bitter.
Gymnopilus junonius is quite distinctive as its yellowish-orange clustered fruitings are often massive with dinner plate-sized mushroom caps. The combination of a clustered habit on wood, orange cap, well developed ring, bitter taste and rusty spores make it easy to identify.
Gymnopilus ventricosus may also occur locally, but the material we have studied generally appears closer to Gymnopilus junonius.
Breitenbach, J. & Kränzlin, F. (2000). Fungi of Switzerland. Volume 5: Agarics (3rd Part). Cortinariaceae. Verlag Mykologia: Luzern, Switzerland. 338 p.
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Hesler, L.R. (1969). North American Species of Gymnopilus. Hafner Publishing Company: New York, NY. 117 p.
Lindsey, J.P. & Gilbertson, R.L. (1978). Basidiomycetes that Decay Aspen in North America. J. Cramer: Vaduz. 406 p.
Orton, P.D. (1960). New check list of British agarics and boleti: Part III. Notes on genera and species in the list. Transactions of the British Mycological Society 43(2): 159-384.
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p.
Watling, R., Gregory, N.M. & Orton, P.D. (1993). British Fungus Flora: Agarics and Boleti. Vol 7. Cortinariaceae p.p.: Galerina, Gymnopilus, Leucocortinarius, Phaeocollybia, Phaeogalera, Phaeolepiota, Phaeomarasmius, Pleuroflammula, Rozites & Stagnicola. Royal Botanic Garden: Edinburgh, Scotland. 131 p.