Cap: 5-12 cm, convex to broadly convex or nearly flat in age; dry; covered with brownish fibers and scales, especially over the center; whitish underneath, or pinkish in wet weather.
Gills: Free from the stem; crowded; pale grayish pink, eventually brown.
Stem: 6-15 cm long; 1-1.5 cm. thick; more or less equal, or with an enlarged base (but not typically ending in a small bulb like Agaricus pocillator); fairly smooth; white; bruising yellow, especially at the base; with a persistent ring; the partial veil when still covering the gills developing brownish to yellowish droplets.
Flesh: White throughout, staining bright yellow in the base.
Odor and Taste: Taste not distinctive or somewhat unpleasant; odor usually unpleasant (phenolic), but sometimes not distinctive.
Spore Print: Brown.
Chemical Reactions: Cap yellow with KOH.
Microscopic Features: Spores 5-7 × 3.5-5 µ; broadly elliptical; smooth.