Cortinarius sinoconfirmatus Zhu L. Yang, Liu K. Jia & Zi R. Wang 2025, sp. nov.

Cortinarius sinoconfirmatus Zhu L. Yang, Liu K. Jia & Zi R. Wang sp. nov. Fig. 6 Etymology. The epithet “ sinoconfirmatus ” (Lat.) refers to the species in China that is similar to C. confirmatus. Holotype. China • Yunnan Province: Lijiang City, Yulong Naxi Autonomous County, Taian Township, in a subalpine temperate coniferous forest with trees of Pinus, 26°48.91'N, 100°5.96'E, elevation 2,633 m, 9 August 2023, Zi-Rui Wang 160 (KUN-HKAS 145320). GenBank: ITS: PQ 772205, nrLSU: PQ 772217. Diagnosis. Cortinarius sinoconfirmatus looks like C. confirmatus Rob. Henry, but differs in its dark brown pileus center, more brown lamellae, thinner stipe, and larger basidiospores (Henry 1983; Mahiques et al. 2001; Ortega et al. 2007; Liimatainen et al. 2017). Description. Basidioma medium-sized. Pileus 1.2 cm diam when young, 3–4.3 cm diam when mature, hemispherical when young, later convex, viscid; pale brown (6 B 2–6 B 4) to brown (5 C 6–5 C 7), covered with white (1 A 1) fibrillose squamules when young; brown (6 C 4–6 C 6), pale brown (6 B 2–6 B 4) towards the margin, dark brown (6 E 7) towards the center when mature; margin covered with brown (6 C 7) fibrillose squamules; context of pileus gelatinous, pale brown (6 B 2–6 B 4) to brown (6 C 7). Lamellae emarginate, crowded (L = 74–95, l = 46–52), pale brown (6 B 2–6 B 3) with a faint pinkish (12 A 2) tint when young, later brown (6 B 6–6 C 6). Stipe 5–7 × 0.5–0.7 cm, cylindrical, dirty white (1 A 1–1 B 1), pale brown (6 B 2–6 B 3) to brown (6 C 6), with a pale violaceous (16 A 2–16 A 3) tint at the stipe apex when young, later the upper 1 / 2 stipe dirty white, pale brown (6 B 2–6 B 3) to brown (6 C 6) with a pale violaceous (16 A 2–16 A 3) tint, covered with brown (7 C 4) fibrillose squamules, the lower 1 / 2 brown to dark brown (7 B 4–7 E 4); context of stipe dirty white (1 A 1–1 B 1) and brown (7 C 6); basal mycelium white (1 A 1). Basidiospores [60 / 3 / 3] 7.5–11.5 × 4–5 (6) μm, Q = (1.5 –) 2–3.13, av. = 9.92 ± 1.19 × 4.85 ± 0.59 μm, Qav. = 2.06 ± 0.28, ellipsoid to narrowly ellipsoid, moderately to strongly verrucose, inamyloid. Basidia 27.5–35 × 5–7.5 μm, 4 - spored, clavate. Trama of lamellae regular, composed of pale yellowish, smooth hyphae 12.5–15 μm wide. Cystidia absent. Pileipellis duplex: epicutis weakly developed, 10–14 μm thick, gelatinous, composed of only 2–4 layers of interwoven to parallel, colorless to pale yellow, smooth, thin-walled, long-celled hyphae 2.5–5 µm wide; hypocutis composed of interwoven to parallel, colorless, cylindrical, thin-walled hyphae 12.5–17.5 μm wide. Clamp connections common in all parts of basidioma. Habitat / host. Summer. Gregarious on soil in subalpine temperate coniferous forests with trees of Pinus. Distribution. Currently known from southwestern China. Additional specimens examined. China • Yunnan Province: Lijiang City, Yulong Naxi Autonomous County, Taian Township, in a subalpine temperate coniferous forest with trees of Pinus, 26°48.91'N, 100°5.96'E, elevation 2,633 m, 9 August 2023, Zi-Rui Wang 154 (KUN-HKAS 145319); same Township and date, 26°48.32'N, 100°4.35'E, elevation 2,700 m, Dong-Mei Li 331 (KUN-HKAS 145318). Notes. Cortinarius sinoconfirmatus is closely related to C. confirmatus, but the latter differs from the former by its paler pileus with vinaceous or violaceous tints, paler, adnate lamellae, more robust stipe, and narrower basidiospores (8.8–10 × 5.2–5.6 μm, Q = 1.55–1.9) (Henry 1983; Mahiques et al. 2001; Ortega et al. 2007; Liimatainen et al. 2017). Cortinarius sinoconfirmatus is also closely related to C. imbutus Fr. and C. saturninus (Fr.) Fr. However, C. imbutus differs from C. sinoconfirmatus by its pale yellow pileus and whitish stipe with somewhat violaceous tint at the stipe apex (Fries 1838), and C. saturninus differs from C. sinoconfirmatus by its dark reddish brown pileus, violet stipe with purplish red squamules (Fries 1838). Morphologically, C. sinoconfirmatus looks like C. lucorum (Fr.) E. Berger, but the latter differs from the former by its pileus with marble-like stripes and more prominent bulbous stipe base (Bidaud et al. 2000; Matheny and Ammirati 2006).