Mycotaxon 8: 90. 1979.
Common Name: none
Misapplied names: Agaricus placomyces Peck; Agaricus meleagris (Schaeff.) Pilát
Cap 7-19 cm broad, cylindrical to convex, expanding to nearly plane in age; surface dry, ground color pallid to white, covered with fine, appressed greyish-brown scales, concentrated at the disc; flesh white, thick, slowly becoming vinaceous when injured; odor strongly of phenol; yellowing in KOH.
Gills free, close, at first whitish, then pink, finally blackish-brown.
Stipe 8-15 cm long, 2-3.5 cm thick, equal to slightly enlarged at base; surface white, smooth above and below the ring; veil membranous, thick, white, upper and lower surface smooth, forming a medially positioned, persistent ring; stipe base typically yellowing when bruised and smelling of phenol.
Spores 4-6.0 x 3.5-4.5 µm, smooth, elliptical; spore print blackish-brown.
Solitary, in small groups, or cespitose clusters on disturbed ground under conifers; fruiting from early to mid-winter.
Toxic; like other phenolic-odored Agaricus species, it can cause gastrointestinal upsets.
Agaricus praeclaresquamosus is a large, strikingly beautiful mushroom which unfortunately for the mycophagist, is toxic. Its squamulose cap and stature resemble Agaricus augustus, an excellent edible, but the latter has tawny-brown not grey-brown cap scales, an anise, not phenol odor, and the flesh does not discolor vinaceous-brown. Additionally, Agaricus praeclaresquamosus fruits from mid to late winter, while A. augustus fruits usually during the late spring, summer and early fall.
Freeman, A.E.H. (1979). Agaricus in the southeastern United States. Mycotaxon 8(1): 50-118. (Protologue)
Kerrigan, Richard W. (1986). The Agaricales (Gilled Fungi) of California. 6. Agaricaceae. Mad River Press: Eureka, CA. 62 p.
Kerrigan, R.W., Callac, P., Guinberteau, J., Challen, M.P. & Parra, L. (2005). Agaricus section Xanthodermatei: a phylogenetic reconstruction with commentary on taxa. Mycologia 97: 1292-1315.
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p.