Large circular clusters; many fleshy, grayish yellow, fan-shaped caps; bruising black when cut or touched. Grows on the ground around stumps and bases of living deciduous trees, especially oaks. July–September. Each cap fan-shaped, semicircular, or spoon-shaped, with a thin, sharp margin; grayish to dull yellowish, darkening along the margin; bruises black when cut or touched; texture fleshy. Pores angular; white, bruising black. Stalk (if present) very short; thick; texture fibrous. Spore print white. Spores magnified are elliptical to round, smooth, colorless.
Lookalikes: Berkeley’s polypore (Bondarzewia berkeleyi) is thick-fleshed and cream-colored. Hen of the woods (Grifola frondosa) has many smaller, grayish brownish caps. Eastern cauliflower mushroom (Sparassis spatulata) has ribbonlike folds. None of these lookalikes bruise black.