Smooth, wavy brown cap with whitish or tannish pores beneath; black, smooth, off-center stalk. Grows singly or in groups on dead wood and stumps of deciduous trees. August–October, but can overwinter. Cap convex to funnel-shaped; dark reddish to brownish, becoming darker with age; texture dry, smooth, tough, leathery. Pores tiny; circular, sometimes with angles; whitish to tannish. Stalk with equal sides; blackish; texture smooth; off-center; tough. Spore print white. Spores magnified are cylindrical, elliptical, smooth, colorless.
Lookalikes: Rooting polypore (Polyporus radicatus) is fleshier, appears to grow from the ground (but is usually on buried wood), and its stalk continues underground with a thick, rootlike filament.