Index Fungorum 15: 2. 2013.
Common Name: none
Synonym: Stropharia semiglobata (Batsch: Fries) Quél.
Cap 2.0-4.0 cm broad, hemispheric, expanding to convex, with or without a low umbo; margin incurved, then decurved, occasionally appendiculate with veil fragments; surface viscid when moist, drying glossy, glabrous, pale-yellow, tinged tan at the disc, not hygrophanous; context up to 5.0 mm thick at the disc, thin at the margin, soft, watery-cream-yellow, unchanging, odor and taste cucumber-like, harsh; mild according to some authors.
Gills adnexed to notched with a decurrent tooth, sub-distant, relatively broad, up to 8.0 mm wide, cream-colored in youth, then greyish, dark purple-brown in age, edges lighter than the faces; lameullae in up to four series.
Stipe 3.0-8.0 cm long, 2.0-5.0 mm thick, slender, stuffed or hollow, equal to slightly enlarged at the base; surface of apex colored like the cap, dry, pruinose-striate, viscid below, cream-colored with scattered light-brown, appressed fibrils, more concentrated towards the base; partial veil pallid, thin, membranous, with a glutinous coating, forming a narrow, superior annulus, flattened to the stipe, soon blackened from spores, or leaving fragments on the cap margin.
Spores 15.0-20.0 x 7.5-10.0 µm, elliptical to almond-shaped in face-view and profile, smooth, thick-walled, with an apical germ pore, purple-brown mounted in water, hilar appendage inconspicuous; spore print purple-brown.
Solitary or in small groups on horse and cow dung or in manured pastures; fruiting throughout the mushroom season after rainy periods; common in its favored habitat.
Protostropharia semiglobata is a slender, dung-dwelling species recognized by a viscid, dull-yellowish cap, viscid lower stipe, and glutinous, evanescent ring. Its occurrence on manure is a helpful but not definitive field character. Other mushrooms that fruit here include Psilocybe coprophila and its close cousin Psilocybe merdaria which differs in having reddish-brown to brown sub-viscid caps and lack of a ring. Panaeolus papilionaceus has a greyish-brown, fringed, non-viscid cap and also lacks a ring. Panaeolus semiovatus is a larger, annulate species with a cream-colored, distinctively wrinkled, viscid cap. Fruitings of Protostropharia semiglobata in manure-rich grass can be confused with Agrocybe pediades and Stropharia coronilla. Both species have similar cream-colored, subviscid caps. Stropharia coronilla, however, differs in possessing a non-viscid, striate-margined annulus, while Agrocybe pediades lacks a ring, and has brown, not purple-brown gills and spores. Finally, compare with Bolbitius vitellinus, which occasionally fruits on dung. It has a viscid, yellowish cap with a striate margin, ochre-colored gills, and lacks a veil. Several varieties of Protostropharia semiglobata have been described, but are not treated separately here.
Ammirati, J.F., Traquair, J.A. & Horgen, P.A. (1985). Poisonous Mushrooms of the Northern United States and Canada. University of Minnesota Press: Minneapolis, MN. 396 p.
Bas, C., Kyper, T.W., Noordeloos, M.E. & Vellinga, E.C. (1999). Flora Agaricina Neerlandica—Critical monographs on the families of agarics and boleti occurring in the Netherlands. Volume 4. Strophariaceae, Tricholomataceae. A. A.Balkema: Rotterdam, Netherlands. 191 p.
Breitenbach, J. & Kränzlin, F. (1995). Fungi of Switzerland. Volume 4: Agarics (2nd Part). Entolomataceae, Pluteaceae, Amanitaceae, Agaricaceae, Coprinaceae, Strophariaceae. Verlag Mykologia: Luzern, Switzerland. 368 p.
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Doveri, F. (2004). Fungi Fimicoli Italici. Associazione Micologica Bresadola: Trento, Italy. 1104 p.
Little, B. (1991). A Systematic Study of Hypholoma and Stropharia for California. Masters Thesis. Humboldt State University: Arcata, CA. 114 p.
Noordeloos, M.E. (2011). Strophariaceae s.l. Edizioni Candusso: Alassio, Italy. 648 p.
Redhead, S. A. (2013). Nomenclatural Novelties. Index Fungorum 15: 1-2. (PDF)
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p.
Watling, R. & Gregory, N.M. (1987). British Fungus Flora: Agarics and Boleti. Vol 5. Strophariaceae & Coprinaceae p.p.: Hypholoma, Melanotus, Psilocybe, Stropharia, Lacymaria, & Panaeolus. Royal Botanic Garden: Edinburgh, Scotland. 121 p.