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

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

Fig. 4 View Figure 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 GoogleMaps .

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 ) GoogleMaps .

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).