Cap 2-5 cm broad, rounded, becoming convex, finally nearly plane; margin incurved when young, occasionally upturned in age; surface lubricous when moist, smooth, pale yellow-buff, margin lighter; flesh white, firm, thick at the disc, thin at the margin; odor faintly sweet; taste mild.
Gills adnate when young, adnexed to slightly descending in age, close, broad, pale lilac-grey, darkening to greyish-purple at maturity.
Stipe 1.5-4.5 cm tall, 4-7 mm thick, solid, stuffed at maturity, sometimes hollow at the apex, equal to tapering downward; surface finely tomentose and white above the ring, smooth to finely fibrillose and pale yellowish-buff below; partial veil white, forming a medial to superior, persistent ring, the upper surface conspicuously striate and colored purple-brown by spores; rhizomorphs frequently at the base.
Spore 7-8.5 x 4.5-5.5 µm, elliptical, smooth, with an inconspicuous apical pore; spore print purple brown.
Solitary, scattered, to gregarious in grass; fruiting spring summer and fall in watered areas, less common during the winter months.
Stropharia coronilla is a small, cream to pale yellowish-buff mushroom that is distinguished by a lubricous when moist cap, and annulus with prominent striations on the upper surface, the latter often tinged purple with spores. It superficially resembles an Agaricus species, but lacks the characteristic free gills. Agrocybe pediades, another grass dweller, is similar in size and color, but lacks an annulus and the spores are dull brown, rather than purple brown.