Cortinarius khinganensis M.L. Xie, T.Z. Wei & Y. Li, 2021

Xie, Meng-Le, Wei, Tie-Zheng, Dima, Bálint, Fu, Yong-Ping, Ji, Rui-Qing & Li, Yu, 2021, Cortinarius khinganensis (Agaricales), a new species of section Illumini from Northeast China, Phytotaxa 500 (1), pp. 1-10 : 5-6

Cortinarius khinganensis M.L. Xie, T.Z. Wei & Y. Li , sp. nov. (Fig. 2)

MycoBank no. MB 839017; Fungal Names FN 570751 .

Diagnosis:—It differs from other species in sect. Illumini by the strongly hygrophanous and translucently striate pileus, white universal veil, weaker verrucose basidiospores, and habitat associated with Larix and Betula trees .

Etymology:—The name refers to the type location, Greater Khingan Mountains.

Type:— CHINA. Neimenggu: Hulunbeier City, Mangui Town, on moist soil under mixed forest ( Larix , Betula and Vaccinium ), 52°05′24″ N, 122°05′06″ E, ASL 630 m, 24 August 2017, Meng-Le Xie, 17xml4583 (HMJAU44507 holotype!). GenBank ITS accession: MT299952 .

Description:—Pileus 17–41 mm diam., hemispherical when young, then plane to plano-convex, usually with a rounded umbo, strongly hygrophanous, vivid brownish red (8C6), somewhat slightly orange to yellowish (5A2-A6) at the margin, translucently striate, especially at the margin. Lamellae adnexed to emarginated, moderately crowded, paler greyish orange (5B3), dark brown (6E6-F8) when dry, edge uneven. Stipe 64–113 mm long, 3–8 mm thick above, cylindrical to subclavate, shiny white fibrillose, the basal mycelium white (A1). Universal veil white (A1), easily disappearing, sometimes forming a thin ring on the stipe apex. Context fairly thin. Odour weakly, somewhat radish.

Basidiospores 6.3–7.5(8.5) × 5.6–6.3(7.2) μm, Q = 1.04–1.24, X av. = 6.8–6.9 × 5.9–6.0 μm, Q av. = 1.15 (60 spores, 2 collections), subglobose, weakly to moderately verrucose, moderately dextrinoid. Basidia clavate, 4-spored, colourless to olivaceous brown in 5% KOH. Lamellar edge fertile, with clavate sterile cells. Cystidia absent. Lamellar trama irregular, hyphae up to 25 μm wide, hyphal wall somewhat encrusted, with some thick-walled hyphae, slightly olivaceous in 5% KOH. Pileipellis duplex; epicuits hyphae 2.5–13 μm wide, slightly olivaceous in 5% KOH, somewhat upwards loosely entangled, hyphal wall encrusted; Hypodermium well-developed, hyphae 19–55 × 7–31 μm, almost colourless to olivaceous in 5% KOH, hyphal wall smooth, some with finely encrusted. Trama hyphae up to 25 μm, almost colourless in 5% KOH. Clamp connections present.

FIGURE. Basidiomata and microscopic structures of Cortinarius khinganensis . a HMJAU44507 (holotype), b HMJAU48631, c Basidiospores (holotype), d Lamellar trama (holotype), e Pileipellis (holotype). Photos by: Meng-Le Xie.

ITS sequence:—The ITS sequence ( MT299952 ) of the holotype of Cortinarius khinganensis is distinct from the other known members of the sect. Illumini and differs from them by at least eight substitutions and indel positions.

Ecology and distribution:—Gregarious or solitary on moist soil in mixed coniferous-deciduous forest. Known from Neimenggu, Northeast China.

Additional specimens examined:— CHINA. Neimenggu: Hulunbeier City, Mangui Town, on moist soil in mixed forest ( Larix , Betula and Vaccinium ), ASL 630 m, 52°05′25″ N, 122°05′05″ E, 24 August 2017, Meng-Le Xie, 17xml4595 (HMJAU48631). GenBank ITS accession: MT299953 .