Chromosera Ambigua Fungal Planet Description Sheets 349

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348 Persoonia – Volume 43, 2019

Chromosera ambigua Fungal Planet description sheets 349

Fungal Planet 1005 – 18 December 2019 Chromosera ambigua Tanchaud, Jargeat & Eyssart., sp. nov. Etymology. The epithet reflects the difficulties encountered in separating Habit, Habitat & Distribution — In small groups on poor san- this species from morphologically close Chromosera ‒ from Latin ambigua dy and clay soil not far from ponds, in a heathland with lichens (doubtful, uncertain). (Cladonia sp.), and surrounded by Erica arborea, E. cinerea, Classification — Hygrophoraceae, Agaricales, Agaricomy- Calluna vulgaris, Ulex europaeus and Pinus pinaster. Other cetes. rare and interesting species found at the same locality included Arrhenia chlorocyanea, Hydropus moserianus, Galerina nana, Basidiomata small-sized, omphalioid. Pileus 5–20(–30) mm Psathyrella flexispora, Plectania rhytidia and Rommelaarsia diam, initially convex to plano-convex with a central depression flavovirens. or soon umbilicate, translucently striate up to the centre, hygro phanous, at first distinctly viscid, entirely whitish, yellow, lilac or Typus. France, Charente-Maritime, Saint-Gemme, La Grande-Vergne, 45.764873°N, -0.931785°E, alt. 10–20 m, 31 Jan. 2016, P. Tanchaud (holo with a combination of these colours. Lamellae moderately dis- type GE18008, ITS, SSU, LSU, RPB2 sequences GenBank MK645573 tant, decurrent, concolorous with the cap, sometimes yellowish to MK645575, MK645581 to MK645583, MK645587 to MK645589 and with a whitish cap. Stipe 10–40 × 1–3 mm, cylindrical, viscid MK645593 to MK645595, MycoBank MB830214). when young, concolorous with the cap or more or less lilac espe- cially at the top. Context concolorous with the surface or paler, Notes — Because of its viscid pileus and stipe, decurrent without distinctive smell or taste. Spores (7.2–)7.4–9.3(–11) × lamellae with non-gelatinised edge but with interwoven trama (4.3–)4.5–5.5(–5.8) μm, Q = (1.4–)1.5–1.9(–2.1), ellipsoid or and sometimes constricted and white spores, this new species amygdaliform, sometimes with concave side or constricted in fits the genus Chromosera subgenus Oreocybe (Boertmann apical part. Basidia 30–40 × 8–9 μm, predominantly 4-spored, 1990, Lodge et al. 2013) that already includes C. xanthochroa, narrowly clavate, clamped. Cystidia absent. Gill trama interwo- C. citrinopallida and C. lilacina. According to Boertmann (1990, ven, with cylindrical elements measuring 35–50 × 8–13 μm, 2010), Candusso (1997) and Borgen & Arnolds (2004), C. citri with yellow extracellular granules on fresh material. Pileipellis nopallida and C. lilacina have an arctic and alpine distribution a thin ixocutis of cylindrical hyphae, 2–5(–8) μm wide. Clamp while C. xanthochroa can also be found in oceanic temperate connections present. areas. Because of its habitat, C. ambigua could therefore be compared with C. xanthochroa, but the latter has the narrowest spores of the subgenus, measuring on average less than 4.5 KF407939 Chromosera lilacina RP: 10705 TENN:58791 Chromosera lilacina GE16112 µm diam, while the average width of the spores of our new 100 Chromosera lilacina Chromosera lilacina GE16115 species easily reaches 5 µm diam. 92 KF291054 Chromosera lilacina T.Borgen 86.294 (CFMR) GE18008-1 100 On the other hand, considering the three species with spores on GE18008-2 Chromosera ambigua sp. nov. 56 GE18008-3 average larger than 4.5 µm, C. citrinopallida is chrome-yellow GU234145 Hygrocybe citrinopallida GG312:86 99 U66435 Hygrocybe citrinopallida Lutzoni:930731-1 DUKE Chromosera citrinopallida and pales to white as it ages, and therefore never presents lilac Chromosera citrinopallida 45 Boertmann:2006.2 CFMR DEN:29 tones, while C. lilacina has a brownish orange to lilac cap and EU784356 Hygrocybe xanthochroa RGB K(m)55746 97 91 Chromosera xanthochroa GE16114 a lilac stem (Consiglio 1997, Hausknecht et al. 2003, Consiglio Chromosera xanthochroa Chromosera xanthochroa GE16110 & Contu 2007, Boertmann 2010). But as already pointed by Chromosera xanthochroa GE16113 AF261455 Chromosera cyanophylla DAOM208603 Boertmann (1990) and Consiglio & Contu (2007), discoloured AF261456 Chromosera cyanophylla DUKE1645 Chromosera cyanophylla 94 Chromosera cyanophylla AFTOL-ID 1684 specimens of the last two species can only be distinguished by MG050103 Chromosera sp. IMG 6589-17 Chromosera sp. 58 their ecological preferences, C. lilacina being more hygrophilous Chromosera cyanophylla TL-5091 (CFMR) 94 KJ194074 Chromosera cyanophylla PRM:922848 Chromosera cyanophylla than C. citrinopallida. Without considering the different ecolo KJ194075 Chromosera cyanophylla WU:28831 gical preferences of the species, yellow and lilac specimens of EU784352 Hygrocybe viola RGB K(m)20264 98 KF477303 Gloioxanthomyces vitellinus LD 1617064 C. ambigua can therefore be respectively confused with C. citr- Gloioxanthomyces vitellinus EU784355 Hygrocybe vitellina RGB K(m)67295 100 Gloioxanthomyces nitidus isolate 2 GDGM41710 Gloioxanthomyces sp. inopallida and C. lilacina, from which they differ essentially by 96 KF468712 Gloioxanthomyces nitidus DJL05NC65c4 TENN:61894 100 their always clearly striate cap vs ‘sometimes short translucently KF468708 Gloioxanthomyces nitidus SC 13 VT (CFMR) Gloioxanthomyces nitidus KF468713 Gloioxanthomyces nitidus DJL05NC65c5 striate from margin’ or ‘± translucently striate’ (Boertmann 2010, see also Borgen & Arnolds 2004). Chromosera viola, which belongs to the subgenus Subomphalia, is readily distinguished PhyML analysis (Guindon & Gascuel 2003) of a combined SSU, ITS, LSU by its completely dry pileus and stipe and broad, subglobose and RPB2 sequence dataset (3 413 positions, including gaps), conducted with and non-constricted spores (Boertmann 2010, Lodge et al. the Geneious® platform placed this species in Chromosera, closely allied to 2013, Sánchez & Gibert 2015). C. lilacina, C. citrinopallida and C. xanthochroa. Chromosera cyanophylla is more divergent and appears to be separated into two groups, one American and one European. The scale bar indicates the number of substitutions per site and the bootstrap support values (based on 500 replicates) are indi- cated above branches. Blue dots are for European specimens, red dots for American specimens and green dots for Asiatic specimens. The alignment and the tree were deposited in TreeBASE (study 24563).

Colour illustrations. France, La Grande-Vergne, part of the heathland where the holotype was collected. Basidiomata in situ (holotype); spores from holotype. Scale bars = 1 cm (basidiomata), 10 µm (spores).

Patrice Tanchaud, 2 rue des Espics, F-17250 Soulignonne, France; e-mail: [email protected] Guillaume Eyssartier, Attaché honoraire au Muséum national d’histoire naturelle de Paris, 180 allée du Château, F-24660 Sanilhac, France; e-mail: [email protected] Patricia Jargeat & Hervé Gryta, Université Paul Sabatier, CNRS, IRD, UMR5174 EDB (Laboratoire Évolution et Diversité Biologique), 118 route de Narbonne, F-31062 Toulouse, France; e-mail: [email protected] & [email protected]