Mycologia 6(3): 144. 1914.
Photo: Young specimens
Common Name: none
Synonym: Hypholoma ambiguum Peck
Cap 4.0-14 cm broad, nearly conic when young, becoming convex to plane, occasionally slightly umbonate; surface pale yellow to straw-colored to orange-yellow, viscid when moist; margin with adhering veil fragments (appendiculate), sometimes disappearing in age; flesh thick, white.
Gills adnate, crowded, grayish when young, becoming purplish-gray to purplish-black.
Stipe 7-17 cm long, 1-2 cm thick, equal to tapering downwards, stuffed when young, becoming hollow at maturity; white, silky at apex, floccose scales from the base to the veil, sometimes becoming smooth in age; veil cottony forming an evanescent superior annulus or annular zone; white rhizomorphs typically at the base.
Spores 10-15 x 6-9 µm, elliptical, smooth. Spore print purple-black.
Solitary, scattered to gregarious, usually in deep humus of our coastal forests under conifers, but also found along streams and in damp shaded areas; from late fall to mid-winter.
Generally considered edible, but very mediocre.
The tall, pale yellow fruiting bodies of Stropharia ambigua are exquisitely beautiful, standing dramatically in the deep shade of the forest floor. The pale yellow, sometimes viscid cap with an appendiculate margin and cottony stipe are important field characters. The aspect of Stropharia ambigua is somewhat similar to Amanita gemmata which also has yellow cap. However, the latter has white spores, free gills, a bulbous base, and lacks the striking appendiculate margin.
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Little, B. (1991). A Systematic Study of Hypholoma and Stropharia for California. Masters Thesis. Humboldt State University: Arcata, CA. 114 p.
Peck, C.H. (1898). New species of fungi. Bull. Torrey bot. Club 25(6): 321-328. (Protologue)
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p.
Zeller, S.M. (1914). The Development of Stropharia ambigua. Mycologia 6(3): 139-145.