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

Cortinarius fuscocandidus Zhu L. Yang, Liu K. Jia & Zi R. Wang sp. nov. Fig. 4 Etymology. The epithet “ fuscocandidus ” (Lat.) refers to the dark brown pileus with a white margin of this species. Holotype. China • Yunnan Province: Lijiang City, Ninglang Yi Autonomous County, Xinyingpan Township, in a subalpine temperate broad-leaved and coniferous mixed forest with trees of Quercus and Pinus, 27°9.9'N, 100°55.63'E, elevation 2,700 m, 7 August 2011, Qing Cai 602 (KUN-HKAS 70198). GenBank: ITS: PQ 772210, nrLSU: PQ 772222. Diagnosis. Cortinarius fuscocandidus resembles C. fulvopaludosus Kytov., Niskanen & Liimat. (Liimatainen 2017), but differs in its white margin, more robust stipe, and broadly ellipsoid to amygdaliform basidiospores. Description. Basidioma small. Pileus 1.8–2 cm diam, applanate to plano-convex with a papilla, viscid; dark brown (6 E 7); margin white (1 A 1), sparsely covered with brown (6 C 6) fibrillose squamules; context of pileus brown (6 D 7). Lamellae emarginate with decurrent tooth, medium-spaced (L = 25–33, l = 9–12), pale brown (6 B 4) with a somewhat pale violaceous (16 A 2) tint. Stipe 5–7 × 0.3–0.6 cm, cylindrical, white (1 A 1) with a somewhat pale violaceous (16 A 2) tint, pale brown (6 B 2–6 B 4) when damaged; annulus cortinate; context of stipe not observed; basal mycelium white (1 A 1) with a somewhat pale violaceous (16 A 2) tint. Basidiospores [60 / 2 / 2] 7.5–10.5 × (5 –) 7–10 μm, Q = 1.07–1.5 (– 1.65), av. = 8.19 ± 1.24 × 6.99 ± 1.26 μm, Qav. = 1.29 ± 0.18, broadly ellipsoid to amygdaliform, occasionally subglobose, strongly verrucose, inamyloid. Basidia 20–22.5 × 7.5–10 μm, 4 - spored, clavate. Trama of lamellae regular, composed of colorless, smooth hyphae 7.5–10 μm wide. Cystidia absent. Pileipellis duplex: epicutis weakly developed, 11–15 μm thick, gelatinous, composed of interwoven to parallel, colorless, smooth, thin-walled, long-celled hyphae 2.5–5 µm wide, with brownish incrustation; hypocutis composed of only 3–5 layers of interwoven to parallel, colorless, cylindrical, thin-walled hyphae 7.5–15 μm wide. Clamp connections common in all parts of basidioma. Habitat / host. Summer. Gregarious on soil in subalpine temperate broad-leaved and coniferous mixed forests with trees of Quercus and Pinus. Distribution. Currently known from southwestern China. Additional specimen examined. China • Yunnan Province: Lijiang City, Gucheng District, Jinshan Township, in a subalpine temperate broad-leaved and coniferous mixed forest with trees of Quercus and Pinus, 26°54.55'N, 100°18.44'E, elevation 2,145 m, 28 July 2011, Li-Ping Tang 1331 (KUN-HKAS 69792). Notes. Cortinarius fuscocandidus is characterized by its dark brown, papillate pileus with a white margin, pale brown lamellae with a somewhat pale violaceous tint, and broadly ellipsoid basidiospores. Phylogenetically, C. fuscocandidus belongs to sect. Hinnulei and is closely related to C. fulvopaludosus. However, the phylogenetic tree shows low support between these two similar species, which can only be distinguished by their margin coloration and basidiospore size (Liimatainen 2017). Morphologically, C. fuscocandidus looks like a typical member of sect. Hinnulei (Fries 1838; Bidaud et al. 2012; Li et al. 2016; Liimatainen et al. 2017; 2020), where the overall coloration of the pileus is brown to dark brown. However, the white margin, somewhat pale violaceous lamellae, and broadly ellipsoid basidiospores (7.5–10.5 × (5 –) 7–10 μm) differentiate it from the most similar species, C. badioflavidus Ammirati et al., which has brown to rich brown lamellae and narrower basidiospores (8.1–10.5 × 5.8–6.5 μm) (Li et al. 2016).