Entoloma rhodopolium (Fr.) P. Kummer (1871: 98)

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 : 221

6. Entoloma rhodopolium (Fr.) P. Kummer (1871: 98) , FIGURE 6 .

≡ Agaricus rhodopolius Fries (1818: 103)

≡ Rhodophyllus rhodopolius (Fr.) Quélet (1886: 59)

= Rhodophyllus nidorosus (Fr.) Quélet (1886: 59)

Description:— Pileus 18–95 mm broad, campanulate, convex, plano-convex to plane, umbonate to subumbonate, hygrophanous, translucent-striate at the margin up to half radius, elsewhere dull, glabrous, smooth, pale to dark yellowish brown, pale greyish brown or pinkish brown, some darker at the centre. Lamellae adnate to emarginate, some with decurrent tooth, subdistant, broad to ventricose, whitish then pink, edge entire, crenate or eroded, concolourous. Stipe 35–120 × 3–15 mm, central, cylindrical, equal, broadening, or tapering towards the base, fibrillose, some with pruinose apex, longitudinally striate, white to whitish, some with yellowish or grey fibrils. Context up to 10 mm broad, fleshy, white to whitish. Odour none to farinaceous. Taste none to farinaceous.

Basidiospores (6.4–) 7.2–10.4 × (6.4–) 7.2–8.8 μm, Lm = 8.6, Wm = 7.8, Q = 1.0–1.3, subisodiametrical, some isodiametrical, rarely heterodiametrical, 5–7 angled in side-view, colourless. Basidia 30–50 × 8–15 μm, 4-spored, clavate to cylindro-clavate, colourless, clamped. Pleurocystidia absent. Cheilocystidia absent. Pileipellis a cutis to ixocutis, terminal elements 24–81 × 4–16 μm, cylindrical to cylindro-clavate and difficult to distinguish, with scarce to abundant yellowish to yellowish brown plasmatic pigment; differentiated subpellis absent. Caulocystidia absent or like undifferentiated terminal elements, 34–56 × 6–10 μm, cylindro-clavate, colourless, in groups at the stipe apex. Clamp-connections present in all tissues.

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

Material studied:— MEXICO. Jalisco, Municipality of Tequila, volcán de Tequila, km 12–15 road to microwave transmission tower, 16 September 2006, I.G. Rocha-Salazar 11 (IBUG!), 3 September 2011, D. Montañez 149, 150 (IBUG!).

Comments:—Our collections fit well with the morphospecies Entoloma rhodopolium as it is described in the literature ( Largent 1994, Noordeloos 2004, Kokkonen 2015), with a pale to medium brown, yellow-brown, or grey-brown pileus, which is glabrous and distinctly translucent-striate at margin. Entoloma clypeatum (L.) P. Kumm. sensu Largent (1994), also associated with Quercus species, is very similar. However, the true E. clypeatum is a European species, differing particularly in ecology, forming a special type of mycorrhiza with rosaceous trees ( Noordeloos 1992). Entoloma lividoalbum (Kühner & Romagn.) Kubička (1975) differs particularly in the more robust basidiomata with a firm context, and a dry or slightly greasy, completely dull pileus, which is not translucent-striate, or at the very margin only ( Noordeloos 1992).

Figures

FIGURE 6. Entoloma rhodopolium. a. Basidiospores. b. Basidia. c. Pileipellis. d. Caulocystidia.All 1000×, except basidiospores 3000×. Drawings by Diego Montañez and Machiel Noordeloos.