Rhodocybe fumanellii Ferrari, Vizzini & Fellin

Vizzini, Alfredo, Ferrari, Renato Jonny, Ercole, Enrico & Fellin, Alessandro, 2018, A new species of Rhodocybesect. Rufobrunnea (Entolomataceae, Agaricales) from Italy, MycoKeys 36, pp. 21-33 : 24-25

Rhodocybe fumanellii Ferrari, Vizzini & Fellin sp. nov. Figs 4, 5

Holotype.

Italy. Veneto, Venezia, Chioggia, Riserva Naturale Integrale Bosco Nordio, 45°7'19.563"N, 12°15'38.046"E, 4 m a.s.l., mixed broadleaved forest with Fraxinus ornus and Quercus ilex , on consolidated dunes, 10 November 2017, Renato Jonny Ferrari & Enrico Bizio (MCVE 29550).

Etymology.

dedicated to Ezio Fumanelli, Italian mycologist, naturalist and photographer.

Habit tricholomatoid (Fig. 4). Pileus 35-100 mm diam, at first convex with large central umbo, soon plane, irregular, with margin slightly inrolled when young, soon plane, strongly undulate, lobate when old, not striate, surface smooth, dry, greasy when wet, not or very slightly hygrophanous, at first reddish-brown (Nopal Red, Brazil Red, Plate I; Pompeian Red, Plate XIII; *Vinaceous-Rufous, Plate XIV) then brick-red (*Brick Red, Plate XIII), light orange to ochre (Flesh Ocher, Apricot Buff, Plate XIV) when old. Lamellae narrow, adnate, quite crowded (L = 60-80), intermixed with lamellulae of variable length [l = 1 –3(– 4)], up to 3-4 mm high, at first whitish-cream (Seashell Pink, Plate XIV; Pale Ochraceous-Salmon, Plate XV), finally pinkish (Pale Salmon Colour, Pale Flesh Colour, Plate XIV) when very old, with an irregular-eroded concolorous edge. Stipe 40-70 × 5-15 mm, cylindrical-clavate (at base to 20-28 mm broad), central, solid, pinkish (Light Corinthian Red, Plate XXVII; Light Congo Pink, *Vinaceous-Pink, Plate XXVIII), covered with a white flocculent-pruinosity, denser towards the apex, the base with a white dense mycelial tomentum and numerous thick white rhizomorphs. Context whitish, pink shaded, marbled, thicker (up to 9 mm) in the disc and thinner in the rest of the pileus, odour aromatic of walnut kernel, a little floury, taste mild, flour-aromatic, not astringent. Spore-print pinkish. Macrochemical reactions (on fresh material): 30% KOH on context and pileus surface negative.

Basidiospores (5.3 –)5.68–6.26–6.83(– 7.3) × (3.5 –)3.93–4.26–4.58(– 5.1) µm (n = 40), Q = (1.22 –)1.34–1.47–1.60(– 1.78), ellipsoid, colourless under the light microscope, finely warty, pustulate, with a wavy profile (angular in polar view with 8-12 facets), walls cyanophilic, inamyloid (Fig. 5a). Lamella edge heterogeneous. Basidia 30-40 × 6.5-7 μm, clavate, 4-spored, thin-walled, sterigmata up to 5 μm long. Basidioles 30-45 × 4.5-6 μm, clavate. Cheilocystidia 35-95 × 3-6.5 μm, scattered, slender, flexuose-cylindrical, sometimes with protuberances and 1-2-septate, thin-walled (Fig. 5c). Pleurocystidia absent. Hymenophoral trama subregular, consisting of cylindrical parallel hyphae (2.5-5 μm) mixed with short, inflated, up to 13 μm wide elements. Pileipellis as a xerocutis, made up of subparallel, thin-walled hyphae, 2‒5 μm wide, orange-brown (in H2O), with presence of granular epiparietal pigment (observable in H2O and NH4OH), terminal elements obtuse (Fig. 5c). Caulocystidia (25 –)30–50(– 69) × (2.5 –)3–4(– 5) µm, slender with a cylindrical-irregular shape, thin-walled (Fig. 5b). Clamp-connections absent everywhere.

Habit, habitat and distribution.

In small groups (gregarious), in the litter of broadleaved trees on sandy soil. So far, known only from the type locality.