Cortinarius tenuifulvescens Kyto ¨v., Niskanen & Liimat.

Index Fungorum number: IF551703 Facesoffungi number: FoF02469

Etymology: The species looks like a slender C. fulvescens.

Holotypus: K. Liimatainen & T. Niskanen 04-572, H6031278 (H)

Pileus 10–30 mm diam., conical to somewhat hemisphaerical, umbonate, later low convex to plane with an umbo or not, up to 1/3 pellucid-striate, surface mat, warm redbrown, hygrophanous. Lamellae adnexed, subdistant, moderately broad, moderately thick, at first lightbrown, becoming medium brown, edges remaining pale for some time, then concolorous. Stipe 40–110 mm long, apex 2–4 mm thick, equal, whitish silky-fibrillose. Universal veil pale pink, very sparse, forming incomplete girdles on the stipe. Basal mycelium white. Context in pileus dark red-brown, in stipe medium yellow-brown. Odour indistinct. Basidia 4-spored, 8–9 x 27–35 um, clavate. Basidiospores 7.5–9.3 x 4.8–5.4 um, Q = 1.48–1.70,ellipsoid to narrowly ellipsoid, finely to fairly finely, densely, evenly verrucose, slightly to somewhat moderately dextrinoid. Lamella trama hyphae moderately to strongly encrusted in MLZ. Pileipellis duplex (in MLZ): Epicutis hyphae 4.5–13 um wide, smooth to encrusted. Hypoderm distinct, elements up to 30 x 70 um. Trama hyphae 5–13 um wide, encrusted. ITS sequence (holotype) distinct from the other known members of the clade Fulvescentes/ Laeti, and differs from them in the ITS region by more than 7 substitutions and indel positions.

Ecology and distribution: In dry to mesic coniferous forests, in northern Europe often on sandy soil, one collection from spruce-hardwood swamp. Widely distributed and found from western and eastern North America and Europe.

Material examined: CANADA, Newfoundland, Avalon Peninsula, Butter Pot Provincial Park, mesic to damp Picea dominated forest with some Abies, Larix and Betula, 25 September 2007, leg. K. Liimatainen & T. Niskanen 07-292, H7000956 (H). FINLAND, Pera ¨-Pohjanmaa, Rovaniemi, Pisavaara nature reserve area, 31 August 2004,
leg. K. Liimatainen & T. Niskanen 04-572, H6031278 (holotype, H;isotype, K). SWEDEN, Ja ¨mtland, Berg, dry Pinus sylvestris heath forest with some Picea and Betula on sandy soil, leg. I. Kyto ¨vuori, K. Liimatainen & T. Niskanen 03-907, H7018168 (H). A ˚ ngermanland, Stro ¨msund, Bodum, at a small sand pit, Picea-hardwood swamp, leg. I. Kyto ¨vuori 97-500b (H). Additional specimens: CANADA, British Columbia, Mt. Washington, Trail to Rossiter Lake, in mossy detritus, 13 Sep 2001, leg. O. Ceska OC43, F17115 (UBC)

Phylogram resulting from the RAxML (Stamatakis 2014) analysis of ITS sequence data. Bootstrap values greater than 50 % are indicated above branches. The names in blue represent the species of Cortinarius presented in this paper and the specimens in boldface are type specimens of the species. The tree is rooted with Obtusi species

Phylogram resulting from the RAxML (Stamatakis 2014) analysis of ITS sequence data. Bootstrap values greater than 50 % are indicated above branches. The names in blue represent the species of
Cortinarius presented in this paper and the specimens in boldface are type specimens of the species. The tree is rooted with Obtusi species

Cortinarius fulvescens

a, f Cortinarius fulvescens 04-935 (neotype, H). b, g C. fulvescentoideus 03-1675 (H). c, i C. pseudobulliardioides 11-452 (holotype, H). d, j C. tenuifulvescens 04-572 (holotype, H). e, h C. nymphatus DBB21430 (UC). Scale bar 10 mm. (a–d Photographs by K. Liimatainen, e by D. Bojantchev. f–j Drawings by T. Niskanen and I. Kytovuori.)

a, f Cortinarius fulvescens 04-935 (neotype, H). b, g C. fulvescentoideus 03-1675 (H). c, i C. pseudobulliardioides 11-452 (holotype, H). d, j C. tenuifulvescens 04-572 (holotype, H). e, h C. nymphatus DBB21430 (UC). Scale bar 10 mm. (a–d Photographs by K. Liimatainen, e by D. Bojantchev. f–j Drawings by T. Niskanen and I. Kytovuori.)