Cap 4-9 cm broad, convex at first with inrolled margin, becoming plano-convex with a broad umbo, margin sometimes upturned in age; surface smooth, viscid when moist, cream to buff shading to a buff-brown disc; flesh thick, white; odor of radish, taste bitter.
Gills close, adnate to adnexed, white becoming pale brown, finely serrate, edges with droplets of liquid when young.
Stipe 4-7 cm tall, 0.7-14 cm thick, equal to enlarged at the base, pallid to concolorous with cap, apex pruinose, i.e. covered with fine powdery granules; veil absent; solid; rhizomorphs usually seen at base.
Spores 9-12 x 6-7 µm, elliptical, slightly roughened. Spore print dull brown.
Solitary, gregarious or in arcs and rings. Very common under live oak (Quercus agrifolia) and conifers (especially Monterey pine) fruiting from after the fall rains to late winter; sporadic fruitings are sometimes seen during the summer in watered areas.
Toxic. The unknown toxins cause a rather severe gastrointestinal syndrome.