Description:— Pileus 25–50 mm broad, convex to plano-convex, subumbonate, hygrophanous, translucent-striate at the margin, elsewhere dull, glabrous, smooth, blackish brown or dark greyish brown, blackish at the centre. Lamellae adnate, subdistant, broad, pink, edge entire or eroded, concolourous. Stipe 50–70 × 6–8 mm, central, cylindrical, broadening towards the base, glabrous, smooth, whitish with pale greyish brown tinges. Context fleshy, white. Odour unpleasant. Taste not recorded.

Basidiospores (8.0–) 8.8–10.4 × 7.2–8.8 μm, Lm = 9.4, Wm = 8, Q = 1.1–1.3, subisodiametrical, some isodiametrical, rarely heterodiametrical, 5–6 (–7) angled in side-view, colourless. Basidia 30–40 × 7–14 μm, 4-spored, clavate to broadly clavate, colourless, clamped. Pleurocystidia absent. Cheilocystidia absent. Pileipellis a cutis, with cylindrical terminal elements 32–98 × 2–8 μm, containing abundant yellowish brown plasmatic pigment. Subpellis differentiated, very inflated hyphae 32–60 × 12–24 μm, colourless. Caulocystidia absent. Clamp-connections present in all tissues.

Habit and habitat:—Gregarious, on soil, in Quercus - Pinus forest.

Material studied:— MEXICO. Jalisco, Municipality of Tequila, volcán de Tequila, road to microwave transmission tower, 21 August 1990, O. Rodríguez 579 (IBUG!).

Comments:—The collection described above represents another member of Rhodopolia from the mixed oak-pine forests in Jalisco. It is characterized by the very dark brown and glabrous pileus, pale brown stipe, the pileipellis with plasmatic pigment only, and the well-differentiated subpellis. As such, it identifies as being very close to the concept of Entoloma nigrobrunneum (Hesler 1967), except for the occurrence of some encrustations in the pileipellis (Noordeloos 1988, Kokkonen 2015). Hesler (1967) described this species as having a slightly depressed, non-umbonate pileus, a farinaceous odour and taste, and lacking clamp-connections. However, the type studies by Noordeloos (1988) and Kokkonen (2015) confirm the abundance of clamp-connections in all the tissues. Entoloma griseorhodopolium (see above) is similar, but has a more greyish colour and a non-differentiated subpellis. Entoloma subradiatum shares many similar features with the Mexican specimen, including the well-developed subpellis, but it has smaller basidiomata, 15–30 mm broad pilei and 27–50 × 1.5–4 mm stipes, and a strongly farinaceous odour (Moser 1978).