Basidiomata solitary or in small clusters of 2 to 4. Cap 3-7 cm diam., campanulate to strongly convex or subumbonate, expanding to applanate, the surface strongly hygrophanous, black with an olivaceous tint when moist, fading from the centre to olive-buff and initially with a dark outer belt; smooth, dry, not viscid, not striate; margin entire, eventually radially fissile. Gills ascendant, adnexed to broadly adnate, brown, finally dark grey-brown, with lamellulae of two lengths. Stipe 5-8 x 0.3-0.5 cm, hollow; surface with dull flesh-pink tones, longitudinally ridged-striate, the upper third covered in a white pruina. Veil absent. Flesh to 5 mm thick at disk, pale brown, brittle, composed of hyaline thin-walled hyphae 2-5 µm in diam., inflated to 30 µm diam., with small clamp connexions. Odour and taste not distinctive. Spore print black. Basidiospores 8.5-11 x 6-7.5 x 4.5-6, Q = 1.86, broadly limoniform, sometimes subhexagonal in face view, ellipsoidal in profile, dark fuscous brown, opaque or nearly so, thick-walled, smooth, with an apical germ pore that is often abaxially inclined. Basidia 24-34 x 8-9.5 µm, cylindric-clavate, 4-spored, with stout sterigmata. Edge of lamella sterile, with crowded cheilocystidia 27-35 x 6.5-11 µm in size with a cylindrical, tapering or subcapitate neck 3.5 -7 µm diam., hyaline, thin-walled. Pleurocystidia and chrysocystidia absent. Hymenophoral trama regular, hyaline, the hyphae thin-walled and 2-4 µm diam., inflated to 20 µm diam. Subhymenial layer 8-12 µm thick, composed of angular cells. Cap surface layer composed of a stratified epithelium of hyphal cells 22-37 x 17-30 µm in size, subglobose, pyriform or broadly clavate, hyaline, thin-walled, with occasional scattered cystidia. Caulocystidia forming fascicles on the upper stipe, 22-35 x 4.5-7.5 µm, sinuous to subcapitate, thin-walled.