Entoloma myrmecophilum (Romagn.) M.M. Moser (1978: 197)

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 : 217-218

4. Entoloma myrmecophilum (Romagn.) M.M. Moser (1978: 197) , FIGURE 4 .

≡ Rhodophyllus myrmecophilus Romagnesi (1974: 386)

Description:— Pileus 22–60 mm broad, plano-convex to plane, subumbonate, not hygrophanous, slightly lubricous, dull, centre rugulose, striate at the margin, fibrillose, dark greyish brown to blackish brown. Lamellae adnate to emarginate, subdistant, broad to ventricose, whitish then pink, edge entire to eroded, concolourous. Stipe 50–130 × 6–10 mm, central, cylindrical, equal, fibrillose, longitudinally striate, whitish with pale greyish brown fibrils, whitish fibrils at the base. Context fleshy, colour not recorded. Odour not recorded. Taste not recorded.

Basidiospores 8.0–10.4 × (6.8–) 7.2–8.8 (–9.6) μm, Lm = 9.2, Wm = 8.1, Q = 1.0–1.3, isodiametrical, some subisodiametrical, rarely heterodiametrical, 5–7 angled in side-view, colourless. Basidia 36–50 × 9–14 μm, 4-spored, clavate, colourless, clamped. Pleurocystidia absent. Cheilocystidia absent. Pileipellis an ixocutis, terminal elements 30–64 × 3–14 μm, cylindro-clavate and difficult to distinguish, with abundant yellowish encrusted pigment and scarce reddish brown to yellowish brown plasmatic pigment. Caulocystidia absent. Clamp-connections present in all tissues.

Habit and habitat:—Solitary or gregarious, on soil, in Quercus - Pinus forest.

Material studied:— MEXICO. Jalisco, Municipality of Tequila, volcán de Tequila, km 11 road to microwave transmission tower, 25 September 2010, V. Quezada 1 (IBUG!), 10 September 2011, F.D. Santos Barba 5 (IBUG!).

Comments:—Within Entoloma subgen. Rhodopolia, Largent (1994) unites the species with robust basidiomata and predominantly encrusted pigment in section Typodochroa Largent. Our collections key out as E. myrmecophilum , which is characterized by the subviscid, rugulose, fibrillose, and blackish brown pileus, fibrillose, white, then pale greyish brown stipe, and by the pileipellis with plasmatic and encrusted pigment. This species is widespread in Europe and North America ( Largent 1994, Noordeloos 2004) and is mainly associated with Quercus species. The Mexican collections thus form the southernmost distribution of this species. Entoloma brunnescipes Largent (1994) differs by having a glabrous pileus and pileipellis hyphae with encrusted pigment only; E. pseudovenosum Largent (1994) has a translucent-striate pileus, lamellae with veins, a cucumber-like odour, and pileipellis hyphae with encrusted pigment only; and E. platyphylloides (Romagn.) Largent (1974) is distinguished by having a rivulose pileus with aeriferous patches. Kokkonen (2015) placed E. myrmecophilum as a synonym under E. sericatum , but Noordeloos (1992) and Largent (1994) described E. sericatum with a translucent-striate, smooth, mainly glabrous, and greyish brown or dark yellowish brown pileus, which is different to E. myrmecophilum .

Figures

FIGURE 4. Entoloma myrmecophilum. a. Basidiospores. b. Basidia. c. Pileipellis.All 1000×, except basidiospores 3000×. Drawings by Diego Montañez and Machiel Noordeloos.