Entoloma spodopus Montanez, Noordeloos & Guzmán-Dávalos, 2016

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 : 225-227

10. Entoloma spodopus Montanez, Noordeloos & Guzmán-Dávalos , sp. nov. FIGURE 10 .

Mycobank No. 817354

Etymology:— spodo (Gr) = ash grey, referring to the grey stipe.

Diagnosis:—Pileus up to 37 mm diam., stipe up to 38 × 3 mm; pileus depressed-umbilicate, with fibrillose, brown squamula on a pale greyish brown background; lamellae marginated, grey-brown; stipe polished, grey; cheilocystidia mainly clavate to cylindro-clavate; pileipellis a trichoderm, hyphae with intracellular brown pigment; clamp connections absent.

Description:— Pileus 8–37 mm broad, convex-campanulate, convex to plano-convex, depressed or umbilicate, dry, dull or translucent-striate at the margin up to half radius, centre velutinous, elsewhere fibrillose-squamulose to fibrillose, smooth or striate, centre dark brown, squamules and fibrils dark brown on a pale greyish brown background. Lamellae adnate to emarginate, some with decurrent tooth, subdistant, broad to ventricose, whitish then pink, edge eroded, marginated greyish brown. Stipe 24–38 × 1–3 mm, central, cylindrical or compressed, equal, cartilaginous, polished, glabrous, with pruinose apex, smooth, grey, with whitish tomentum at the base. Context very thin, grey. Odour sweet. Taste none or slightly sweet.

Basidiospores 9.6–13.6 (–14.4) × 6.4–8.8 μm, Lm = 11.8, Wm = 7.6, Q = 1.3–1.7, heterodiametrical, 6–8 angled in side-view with rather blunt, rounded angles, colourless. Basidia 18–36 × 9–12 μm, 2- and 4-spored, clavate to ellipsoid, colourless or with yellowish vacuolar pigment, clampless. Pleurocystidia absent. Cheilocystidia 32–76 (–96) × 8–19 μm, clavate to cylindro-clavate, some lageniform or ventricose with mucronate apex, reddish brown, forming a sterile layer. Pileipellis a trichoderm at the centre, a cutis at the margin, terminal elements 44–128 × 7–33 μm, cylindro-clavate with abundant greyish brown plasmatic pigment. Caulocystidia 29–96 × 4–12 μm, cylindrical, some flexuose, colourless, in groups at the stipe apex. Clamp-connections absent.

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

Material studied:— MEXICO. Jalisco, Municipality of Zapotlán el Grande, slopes of Nevado de Colima, El Floripondio, 11 September 1998, Y. Alquiciras 96 (Holotype, IBUG!).

Comments:— Entoloma spodopus belongs to subgenus Cyanula on account of the depressed-umbilicate and fibrillose-squamulose pileus, polished stipe, and microscopic features, such as the pileipellis, intracelluar pigment, and clampless hyphae. Distinctive for this species is the grey-brown marginated lamellae edge. In an attempt to identify this species with Largent’s key (1994), we tried both Cereicaules Largent and Caesiocaules Largent sections for a match because of the grey, polished stipe. In the Cereicaules, most of the morphological characters of the collection fitted rather well with the description of E. fuligineomarginatum Largent (1974) , which is widespread in the Western United States ( Largent 1977, 1994). In particular, the greyish brown pileus, greyish brown marginated lamellae edge, basidiospore dimensions, and mainly clavate to cylindro-clavate cheilocystidia are distinctive. However, Largent described the stipe as having a fuligineous brown to red-brown colour, particular when fresh, whereas the Jalisco collection has a more pure grey, polished stipe. In the Caesiocaules, no satisfactory match could be found. In Europe, several species occur with a coloured lamellae edge. In Noordeloos (2004), we came to E. exile (Fr.) Hesler (1967) , which has a slightly differently coloured pileus, generally blue tinges in the stipe, and much larger basidiospores. The complex of E. poliopus (Romagn.) Noordeloos (1979) is also similar, but with a blue stipe. Among other taxa with a grey-brown lamellae edge is E. fuscomarginatum P.D. Orton (1960) , with dark brown to reddish brown background of the pileus and some tibiiform and lecythiform cheilocystidia ( Hesler 1967). For the reasons mentioned above, it seems best to describe the Mexican collection as a new species.

Figures

FIGURE 10. Entoloma spodopus. a. Basidiospores. b. Basidia. c. Cheilocystidia. d. Pileipellis. e. Caulocystidia. All 1000×, except basidiospores 3000×. Drawings by Diego Montañez and Machiel Noordeloos.