Entoloma cf. nigrobrunneum Hesler (1967: 107)

Montañez, Diego, Noordeloos, Machiel E., Rodríguez, Olivia, Vargas, Ofelia & Guzmán-Dávalos, Laura, 2016, Notes on the genus Entoloma (Basidiomycota, Agaricales) in two volcanic areas of Jalisco, Mexico, Phytotaxa 277 (3), pp. 211-236 : 219-220

5. Entoloma cf. nigrobrunneum Hesler (1967: 107) , FIGURE 5 .

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).

Figures

FIGURE 5. Entoloma cf. nigrobrunneum. a. Basidiospores. b. Basidia. c. Pileipellis. All 1000×, except basidiospores 3000×. Drawings by Diego Montañez and Machiel Noordeloos.