|California Fungi—Agaricus californicus
(Photo: © Fred Stevens)
Bull. Torrey Bot. Club 22:203. 1895.
Cap 4-11 cm broad, cylindrical to convex becoming plane at maturity, sometimes with a broad umbo; surface dry, smooth to fibrillose, white on the cap margin shading to a grayish-brown disc; surface sometimes bruising pale yellow, conspicuously yellow in KOH; odor faintly of phenol, most noticeable in young specimens.
Gills free, close, pallid at first, then bright pink, pinkish-brown and finally blackish-brown.
Stipe 3-7 cm long, 0.4-1.0 cm thick, smooth, equal, to slightly bulbous at base; partial veil membranous, upper surface smooth to finely striate, lower surface minutely fibrillose, forming a well developed median to superior ring, the latter with a distinctive thickened margin.
Spores 5-7.5 x 4-5.5 µm, elliptical, smooth; spore print blackish-brown.
Scattered, clustered or in broad arcs in a variety of habitats,
lawns, gardens, under both hardwoods and conifers, occasionally well-decayed wood chips; fruiting whenever moisture is available but most abundant from late summer in watered areas to early winter.
Mildly toxic. Causes gastrointestinal upsets for most people although some individuals are able to eat it without negative effects.
is frequently confused with its somewhat larger cousin
. Both species have caps with brownish discs and pale margins although
may be entirely white if developing in deep shade. They are best told apart by odor and bruising reactions.
has a faint, usually barely discernable phenolic odor while fresh specimens of
usually have a pronounced phenolic odor. Additionally, fresh mataerial of
bruise bright yellow on the cap margin and stipe base, while in
the yellow-bruising is faint, if at all.
can be separated from other
species that may have a brownish disc, e.g.
by its annulus with a thickened "double-lipped" margin.
Desjardin, D.E., Wood, M.G. & Stevens, F.A.
(2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
(1986). The Agaricales (Gilled Fungi) of California. 6. Agaricaceae. Mad River Press: Eureka, CA. 62 p.
of North America. New York Botanical Garden: Bronx, NY. 574 p.
Kerrigan, R.W., Callac, P., Guinberteau, J., Challen, M.P. & Parra, L.
: a phylogenetic reconstruction with commentary on taxa. Mycologia 97: 1292-1315.
(1895). New species of fungi. Bull. Torrey bot. Club 22(5): 198-210. (
Other Descriptions and Photos
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The Fungi of California
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