Cortinarius vernalianomalus M. L. Xie, L. L. Qi, T. Z. Wei & Y. Li 2025, sp. nov.

Cortinarius vernalianomalus M.L. Xie, L.L. Qi, T.Z. Wei & Y. Li, sp. nov. MB 843756. Figs 5E, F, 6S, 7S. Etymology: The name refers to sect. Anomali species with spring fruiting pattern. Typus: China, Guangxi Zhuang Autonomous Region, Cangwu County, Wangfu Town, Bahui Village, in Castanopsis chinensis forest with scattered Phyllostachys, alt. 30 m, 23 Apr. 2021, L.L. Qi (holotype HMJAU 48770, isotype HMAS 285290). Pileus 10–35 mm diam., hemispherical when young, later plano-convex to plane, surface covered violet squamules, greyish orange with age, dully greyish violet at first, then greyish orange at the centre. Lamellae, emarginate, moderately crowded, greyish violet when young, then greyish brown to brown, edges paler and uneven. Stipe 30–60 mm long, 3–5 mm thick, cylindrical to subcylindrical, slightly thickened at the base, up to 9 mm, bluish tinged at the apex, surface thin fibrillose, basal mycelium pale violet. Universal veil white, very sparse. Context thin, greyish violet. Odour radish. Taste mild. Basidiospores 6.3–7.5 × 5.5–6.2 μm, Q = 1.09–1.28, Xav. = 6.9 × 5.8 μm, Qav. = 1.18, subgloboid to broadly ellipsoid, rather weakly to moderately verrucose. Basidia clavate, 4-spored, hyaline to subhyaline, rarely yellowish to yellowish brown. Lamellar edge fertile. Pileipellis duplex: epicutis thinly developed, hyphae hyaline to purplish, 5–12 μm wide, smooth; hypocutis well developed, hyphae 10–50 μm wide, hyaline, irregular, somewhat cellular, smooth. Clamp connections present. Ecology and distribution: Gregarious in subtropical evergreen broadleaf forest, associated with Castanopsis chinensis. Known from Guangxi and Yunnan of China. Additional specimen examined: China, Guangxi Zhuang Autonomous Region, Xingye County, Beishi Town, Hongfu Village, in Castanopsis chinensis forest, alt. 100 m, 23 May 2021, Q. Yang, HMAS 298141. Additional nrITS sequences data from public sequence repositories: China, Yunnan Province, MW374218, rxsbn-456 as C. rigens in GenBank. Notes: Cortinarius vernalianomalus is characterized by a dully greyish violet and small basidiomata, with a subtropical distribution, a spring fruiting pattern, and occurring in habitats with Castanopsis chinensis. The small basidiospores are subgloboid to broadly ellipsoid, on average 6.9 × 5.8 μm. The nrITS sequence of the holotype differs from other known members of sect. Anomali by at least 29 substitutions and indel positions. The phylogenetic analyses also support C. vernalianomalus as a separate species from other members in sect. Anomali. The sequence MW374218 (rxsbn-456, as C. rigens) from a specimen in Yunnan Province is considered as the new species because it clusters with our specimens.