Cap up to 20 cm, hemispherical then convex, flat-convex, flat to depressed, initially dry, velvety, later smooth, sometimes slightly viscid, black brown, dark brown to chestnut brown, in young fruitbodies more or less uniformly coloured, later with irregular paler brown, bronze or orange brown spots, unchaning when bruised. Stipe clavate or rarely cylindrical, beige, orange brown to chestnut brown, rarely white or whitish, with fine network, surface unchanging when bruised. Flesh white, under the cuticle with dirty pink or pale brown tint, unchanging when exposed to air. Tubes initially white, then cream, pale yellow to yellow with olivaceous tint, unchanging when exposed to air. Pores concolorous with the tubes, unchanging when bruised. Smell not distinctive. Taste not distinctive. Spores 10.5–19.0 × 3.5–7.0 μm, ratio 1.9–4. Pileipellis (the cap cuticle) a trichodermium of interwoven septate hyphae. Cells of the hyphae long cylindrical, not incrusted. Chemical reactions: Hyphae of the stipe base inamyloid.