Mycena huangsangensis L. N. Liu, 2025

Mycena huangsangensis L. N. Liu sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3

Diagnosis.

Differs from the most similar species, M. alniphila , by its decurrent lamellae and longer basidiospores.

Holotype.

China • Hunan Province, Shaoyang City, Suining County, Hunan Huangsang National Nature Reserve , 26°24'18"N, 110°05'37"E, elev. 644 m, 24 April 2024, LiNa Liu, HUIF 50526 About HUIF (collection number NN 526). GoogleMaps

Etymology.

Refers to the Huangsang National Nature Reserve, from where the holotype was collected.

Description.

Pileus 1–5 mm diam., hemispherical to obtusely conical, expanding with age, umbilicate or depressed center, sulcate, translucent-striate, pruinose and pubescent, light brown (6 B 4–6 B 7) to dark brown (6 E 7–6 E 8), or brownish-pink (7 A 4–7 B 4), paler brown towards margin. Context white, thin, fragile. Lamellae 9–11 reach the stipe, with 1–2 tiers of lamellulae, decurrent, white (4 A 1) to brown (7 D 7), edge concolorous with face. Stipe 6–25 × 1–2 mm, cylindrical, hollow, fragile, light brown (6 B 4–6 B 7) to brown (6 E 5–6 E 8) at the base, gradually becoming paler to white (4 A 1) towards the apex. Base covered with white fibrils. Odor and taste indistinctive.

Basidiospores 6.0–7.4 (7.8) × (3.2) 3.4–4.2 (4.3) μm, Q = 1.4–2.1, Q = 1.8 ± 0.2, pip-shaped, elongated, hyaline, smooth, thin-walled, amyloid. Basidia 15.4–20.9 × 6.2–9.0 μm, 4 - spored, clavate. Cheilocystidia 13.2–25.0 × 8.5–19.9 μm, abundant, clavate to obpyriform, covered with fairly numerous, simple to furcate, cylindrical excrescences. 1.2–9.5 × 0.5–1.4 μm. Pleurocystidia absent. Hyphae of the pileipellis 12–27 μm wide, densely covered with warts or short cylindrical excrescences. Hyphae of the stipitipellis 1.0–3.0 μm wide, densely covered with simple, cylindrical excrescences 1.0–3.2 × 0.8–1.5 μm. Clamp connections are present in the basidia, pileipellis, and stipitipellis hyphae.

Habitat.

Gregarious on decaying leaves of deciduous trees.

Known distribution.

Shaoyang City, Hunan Province.

Additional materials examined.

China • Hunan Province, Shaoyang City, Suining County, Hunan Huangsang National Nature Reserve , 26°24'21"N, 110°05'36"E, elev. 675 m, 24 April 2024, LiNa Liu, HUIF 50528 About HUIF (collection number NN 528) GoogleMaps .

Notes.

Mycena huangsangensis can be considered to be a member of sect. Polyadelphia owing to very small basidiomata, a small number of lamellae, and a slender stipe and hyphae of the pileipellis, which are ornamented with short warts. Mycena huangsangensis belongs to the section with a brownish pileus, while M. alniphila Robich shows the most significant morphological similarity to M. huangsangensis . They have similar basidiomata color and shape of cheilocystidia, pileipellis hyphae densely covered with cylindrical excrescences, and diverticulate stipitipellis hyphae. However, M. alniphila differs in having adnate lamellae, slightly longer spores measuring 8.5–11.0 × (3.5) 4.0–5.5 μm, simple cheilocystidia without branching, and caulocystidia present ( Robich 2003). Mycena albiceps and M. catalaunica Robich are somewhat similar to the new species; in particular, they share the same basidiomata shape and similar habitats. Mycena albiceps differs in the white colors of the pileus and black stipe ( Gilliam 1976; Maas Geesteranus 1986). The latter, M. catalaunica , has a pale violaceous pink to pale vinaceous pink pileus, subglobose spores, and caulocystidia; the clamp connection is absent in all tissues, and cheilocystidia are subglobose ( Robich 2003).