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

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

Fig. 5 View Figure 5

Etymology.

The epithet “ neodisjungendus ” (Lat.) refers to its similarity to C. disjungendus .

Holotype.

China • Yunnan Province: Pu’er City, Jingdong Yi Autonomous County Ailao Mountain Subtropical Forest Ecosystem Research Station, Chinese Academy of Sciences , in a subtropical broad-leaved forest with trees of Quercus , 24°32.57'N, 101°1.62'E, elevation 2,532 m, 8 October 2021, Jian-Wei Liu 2505 ( KUN-HKAS 145322 ). GenBank: ITS: PQ 772207, nrLSU: PQ 772219 GoogleMaps .

Diagnosis.

Cortinarius neodisjungendus differs from other species within sect. Disjungendi by its plano-convex pileus with an umbo, pale brown coloration, and relatively larger basidiospores ( Karsten 1893; Niskanen 2014; Liimatainen et al. 2015).

Description.

Basidioma medium-sized. Pileus 3.5–4.2 cm diam, applanate to plano-convex with an umbonate center, viscid with hygrophanous streaks; pale brown to brown (6 D 3–6 D 4), dark brown (6 E 6) towards the center, white (1 A 1) to pale brown (6 B 2) towards the margin, sparsely covered with white (1 A 1) fibrillose squamules; context not observed. Lamellae emarginate, crowded (L = 52–61, l = 48–53), pale brown (6 B 4) to brown (6 D 6). Stipe 8–10 × 0.5–0.8 cm, cylindrical with a subbulbous base 1–1.5 cm wide, white (1 A 1) to pale brown (6 B 2–6 B 4), base sparsely covered with brown (6 C 5) fibrillose squamules; basal mycelium white (1 A 1).

Basidiospores [60 / 2 / 2] 11–13.5 (– 15) × (5 –) 7.5–9 μm, Q = 1.43–1.71 (– 2), av. = 12.73 ± 0.93 × 7.52 ± 0.96 μm, Qav. = 1.71 ± 0.2, broadly amygdaliform, strongly verrucose, inamyloid. Basidia 32.5–40 × 7.5–10 μm, 4 - spored, clavate. Trama of lamellae regular, composed of colorless to brownish, smooth hyphae 10–12.5 μm wide. Cystidia absent. Pileipellis duplex: epicutis weakly developed, 8.5–15 μm thick, composed of only 3–5 layers of interwoven to parallel, colorless to brownish, smooth, thin-walled, long-celled hyphae 2.5–5 µm wide; hypocutis composed of interwoven to parallel, colorless to pale brownish, cylindrical, thin-walled hyphae 12.5–15 μm wide. Clamp connections common in all parts of basidioma.

Habitat / host.

Autumn. Solitary on soil in subtropical broad-leaved forests with trees of Quercus .

Distribution.

Currently known from southwestern China.

Additional specimen examined.

China • Yunnan Province: Pu’er City, Jingdong Yi Autonomous County Ailao Mountain Subtropical Forest Ecosystem Research Station, Chinese Academy of Sciences , in a subtropical broad-leaved forest with trees of Quercus , 24°32.57'N, 101°1.62'E, elevation 2,532 m, 8 October 2021, Jian-Wei Liu 2529 ( KUN-HKAS 145323 ) GoogleMaps .

Notes.

Cortinarius neodisjungendus is characterized by its hygrophanous, pale brown to brown pileus with a whitish margin, whitish stipe, and relatively larger basidiospores. All other species in sect. Disjungendi have a brownish pileus lacking a white margin, a brown stipe, and smaller basidiospores (range from 9–11 μm long, 6–7 μm wide) ( Karsten 1893; Niskanen 2014; Liimatainen et al. 2015, 2020).