Contrib. Étude Hymén.: 187. 1926.
Common Name: Haymaker's mushroom
Synonyms: Paneolina foenisecii, Psathyrella foenisecii
Cap 1.5-3.0 cm broad, conic, becoming convex, broadly so at maturity; surface smooth to faintly wrinkled, cracking in dry weather, hygrophanous, dull brown fading to light greyish-brown, the margin often with a dark band; flesh thin, light brown; odor and taste mild.
Gills broad, adnate to seceding, close, light brown at first, dark brown in age, the edges lighter, mottled at maturity.
Stipe 3-7 cm tall, 2-3 mm thick, hollow, fragile, equal to tapering downward; surface pallid, darker at the base, indistinctly longitudinally striate; veil absent.
Spores 12-14 x 6-7.5 µm, elliptical, minutely warted, with an apical pore; spore print dark-brown to purple-brown.
Scattered to gregarious in grassy areas, e.g. lawns, golf courses and playing fields; fruiting from late spring to early fall.
Doubtful; too small and unsubstantial to be of culinary value; said to contain insignificant amounts of the hallucinogenic compounds psilocin and psilocybin.
Although common in grass during the warmer months of the year, Panaeolus foenisecii is easily overlooked due to its diminutive size and drab coloration. It often fruits with other lawn species like Marasmius oreades, Leucoagaricus naucinus, Agaricus californicus, A. campestris and A. arvensis. Panaeolus foenisecii is distinguished by a hygrophanous, brown cap, gills which are mottled at maturity, a fragile, hollow stipe, and dark-brown to purple-brown spores. It is most likely to be confused with Psathyrella gracilis. This species, actually a species complex, is similar in size, cap color, spore color and even has a fragile, hollow stipe. It however lacks mottled gills and grows typically in wood chips rather than in grass.
Knudsen, H. & Vesterholt, J. ed. (2008). Funga Nordica: Agaricoid, boletoid and cyphelloid genera. 965 p.
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p.
Watling, Roy & Gregory, Norma 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.