Ecology: Mycorrhizal with oaks and, perhaps, with other hardwoods; growing alone, scattered, or gregariously; summer and fall; widely distributed east of the Rocky Mountains, but especially common in the southeastern United States and in Mexico.
Cap: 3-10 cm; flat, with a central depression, or shallowly vase-shaped; the margin usually becoming scalloped or pleated by maturity, at least shallowly; smooth or somewhat wrinkled, especially in age; bald or very finely velvety; whitish to yellowish buff, eventually darkening to light brown or grayish brown.
Gills: Beginning to run down the stem; very distant (about 1-3 mm apart at the margin); yellowish; stained salmon pink (sometimes slowly) by the milk.
Stem: 3-8 cm long; 0.5-1.5 cm thick; equal or tapered to base; smooth; colored like the cap or paler; dry; hollowing.
Flesh: Soft; whitish; staining salmon pink when sliced.
Milk: White; drying pink; staining tissue pink.
Odor and Taste: Odor not distinctive; taste acrid (or sometimes mild, especially in older specimens).
Spore Print: Creamy or buff.
Chemical Reactions: KOH negative on cap surface.
Spores 7-9.5 × 7-8 µ; subglobose; ornamentation 1.5-2.5 µ high, as amyloid spines and wide, branched ridges that do not generally form reticula. Pleuromacrocystidia absent. Cheilocystidia subcylindric; to about 35 × 5 µ. Pileipellis a trichoepithelium or trichopalisade, with terminal cells cylindric to subclavate.