Laccaria mangshanensis Y. D. Xu & Z. M. He 2025, sp. nov.

Laccaria mangshanensis Y. D. Xu & Z. M. He sp. nov. Figs 2 d – f, 4, 6 c, d Etymology. ‘ mangshanensis ’ referring to the locality of the holotype. Diagnosis. Laccaria mangshanensis has a pale rosy, hemispherical, radially translucent-striate pileus, pinkish adnate lamellae, a reddish equal stipe, globose to subglobose echinulate basidiospores, and cheilocystidia. Type. China • Hunan Province: Yizhang County, Mangshan National Nature Reserve, at 24.866667°N, 112.721944°E, alt. 1200 m, 28 July 2016, P. Zhang 2350 (MHHNU 8850, holotype). Description. Basidiomata small. Pileus 10–30 mm in diam, convex to hemispherical, centrally depressed, surface tomentose, dry, not hygrophanous, reddish-brown (7 A 5) to rosy (7 A 6) when young, then fading to pink-beige (7 A 2); margin strongly striate, rugulose-striate or rugulose-sulcate, involute to inflexed. Lamellae adnate, distant, pinkish (7 A 2) to white (1 A 1), narrow (about 2 mm high), entire, ventricose. Stipe 20–70 × 2–5 mm, central, equal, hollow, obviously flexible, reddish (7 B 5) to dull red (7 C 6), surface with distinct whitish fibrillose coating, base with white (1 A 1) tomentum. Context thin, whitish (2 A 1). Basidiospores [100 / 4 / 2] (6.5) 7–8.5 (10) × (6) 6.5–8.5 (9) μm, Q = (0.86) 0.93–1.18 (1.31), Qm = 1.05 ± 0.08, mostly globose to subglobose, thin-walled, inamyloid, cyanophilous, hyaline, echinulate, spines (0.5) 1–1.2 (1.5) μm long, 0.3–0.8 (1) in width, subdistant; hilar appendix 0.8–1.5 μm long, subtruncate. Basidia 38–47 × 10–13 μm, 4 - spored, clavate, sharply narrowed, thin-walled, hyaline; sterigmata up to 9 μm long. Pleurocystidia lacking. Cheilocystidia 25–55 × 3–5 μm, filamentous to narrowly clavate, flexuose, thin-walled, hyphae, abundant. Lamellar trama regular to subregular; hyphae cylindrical, hyaline, thin- walled, 3–8 μm wide. Pileipellis a cutis, composed of thin-walled, interwoven, cylindrical hyphae 4–10 μm wide, with exserted ends, hyphae. Stipitipellis a cutis, composed of appressed, parallel, thin- to slightly thick-walled (ca. 0.5 μm) hyphae. Clamp connections present in all parts of basidiomata. Ecology. Single, in clusters or in groups, on soil, under the trees of Fagaceae, in subtropical montane coniferous and broadleaved mixed forest, summer (Jul.). Distribution. Known from Central China. Additional specimen examined. China • Hunan Province: Yizhang County, Mangshan National Nature Reserve, at 24.869722°N, 112.721944°E, alt. 1200 m, 29 July 2016, P. Zhang 2356 (MHHNU 8856). Notes. Laccaria fengkaiensis F. Liand L. mangshanensis share pale red to pastel red basidiomata, but the former can be distinguished from the latter by the larger pileus (50–90 mm pileus width vs. 10–30 mm in L. mangshanensis), smaller basidiospores (5–6 × 5–6 μm vs. 7–8.5 × 6.5–8.5 μm in L. mangshanensis), and the presence of pileocystidia (Li 2020). However, the phylogenetic analysis (Fig. 1) suggests that L. mangshanensis represents a well-supported clade with strong support (Species 41, 94 % BP, 0.94 PP), and is clearly separated from L. fengkaiensis (Species 65).