Rhodocybe formosa (Agaricales, Entolomataceae): new collections, molecular data and synonymy, and Rhodocybe griseonigrella comb. nov. Author Vizzini, Alfredo Department of Life Sciences and Systems Biology, University of Torino, Viale P. A. Mattioli Author Picillo, Bernardo Via Roma 139, I- 81017 Sant’ Angelo d’Alife (CE), Italy Author Ercole, Enrico Department of Life Sciences and Systems Biology, University of Torino, Viale P. A. Mattioli Author Vila, Jordi P. O. Box 30041, 08034 Barcelona, Spain Author Contu, Marco Department of Life Sciences and Systems Biology, University of Torino, Viale P. A. Mattioli & Via Marmilla 12, I- 07026 Olbia (OT), Italy & Department of Life Sciences and Systems Biology, University of Torino, Viale P. A. Mattioli text Phytotaxa 2016 2016-04-05 255 1 34 46 http://dx.doi.org/10.11646/phytotaxa.255.1.3 journal article 10.11646/phytotaxa.255.1.3 1179-3163 13675306 Key to the European species of Rhodocybe sect. Rhodocybe 1 . Pileipellis with numerous globose elements................. R. praesidentialis Consiglio, Contu, M. Roy, Selosse & Vizzini (2007: 26) ‒ Pileipellis consisting only of cylindrical hyphae without globose or inflated elements....................................................................2 2 . Spores subglobose to broadly ellipsoid..............................................................................................................................................3 ‒ Spores ellipsoid to amygdaliform.......................................................................................................................................................4 3 . Spores (5‒)5.5‒6.5(‒7.6) × (4.2‒)4.5‒5.5(‒6) μm, Q = 1.16‒1.38, pileus up to 55 mm broad, context unchanging when bruised, lamellae medium crowded, grey to brown .......................................................................................... R. formosa (= R. minutispora ) ‒ Spores 5.7‒8 × 4.5‒5.9 μm, Q = 1.1‒1.5, pileus up to 25 mm broad, context darkening to blackish when old or bruised, lamellae quite distant, dark grey ............................................................................................................................................. R. griseonigrella 4 . Light blue to violaceous tinges present at least at stipe apex and well-developed cylindrical caulocystidia ................. R. ardosiaca ‒ Stipe without violaceous tinges and caulocystidia.............................................................................................................................5 5 . Basidiomes slender, fragile, conical-convex pileus with argillaceous to pale brown tinges (white in var. virgineopusilla ), unpleasant smell and taste (like rotten fish), large spores, 7.5‒10 × 4.5‒5.5 μm....................................................................... R. obtusatula ‒ Basidiomes less fragile, with different smell and smaller spores.......................................................................................................6 6 . Pileus at first covered with abundant white pruina (as a micaceous sheen).......................................................................................7 ‒ Pileus without white pruina................................................................................................................................................................9 7 . Pileus 6–18 mm broad, conico-convex to conical, with a broad obtuse umbo, bright yellow-brown, dark brown at centre, not cracked, lamellae yellow-brown...................................... Clitopilus djellouliae Contu, Vizzini, P. Roux & Guy Garcia (2011: 158) ‒ Pileus 4–30 mm broad, convex, soon convex-depressed, without umbo, dark grey, greysh- brown, minutely cracked, lamellae grey.....................................................................................................................................................................................................8 8 . Pseudocystidia abundant, 40–70 × 6–8 μm......................................................................................................................... R. caelata ‒ Pseudocystidia rare, 30–40 × 3–4 μm .................................................................................................................................... R. dubia 9 . Pileus blackish brown, spores, 6.8‒9 × (5.7‒)6.2‒7.5 μm and large basidia, 32‒44 × 9.5‒13.5 μm, pseudocystidia up to 13 μm wide, filled with colourless contents in KOH, and growth in dwarf shrubs in tundra .............................................. R. finnmarchiae ‒ Not as above.....................................................................................................................................................................................10 10 . Spores oblong to subfusiform, Q = 1.7‒2.1............................................ Clitopilus marinaensis Vila, Contu & F. Caball. (2009: 9) . ‒ Spores ellipsoid or amygdaliform, Q ≤ 1.7......................................................................................................................................11 11 . Pileus 10‒15 mm broad, spores ellipsoid, pseudocystidia non-septate with strongly dextrinoid contents..................... R . oss-emeri ‒ Pileus 20‒30 mm broad, spores amygdaliform, rare uniseptate pseudocystidia present, pseudocystidia with only weakly dextrinoid contents.............................................................................................................................................................................. R. brunnea