Lyophyllum hemigaleatum R. Y. Li, S. M. Tang 2026, sp. nov.
Year: 2026
Type: article
Abstract: Lyophyllum hemigaleatum R. Y. Li, S. M. Tang sp. nov. Figs 2 D, 5, 6 Chinese name. 盔盖离褶伞 (Kui Gai Li Zhe San). Etymology. hemigaleatum (half-helmeted), describing the distinctive hemispherical pileus resembling a warrior’s helmet. Holotype. China, Yunnan Province, Dali City, Jianchuan County, elev. 2,200 m, 7 September 2024, Rui-Yu Li, 9714 (HKAS 150782!). Description. Pileus 1.4–1.8 cm, hemispherical when young, inflexed of margin; becoming convex when mature, sometimes slightly depressed in the centre, dry, glabrous, slightly desaturated orange (# d 0 a 87 b) on centre, dark at the margin, dark moderate orange (# 75533 a); pileus context white (# ffffff), 0.1–0.2 cm thick, fleshy, thinner toward its margin, slightly desaturated orange (# b 99 b 7 e) when exposed or injured. Lamellae moderately close together, adnate to emarginate, broad, white (# ffffff), 2–4 tiers, 0.3–1.0 cm wide, edge even or entire to undulate. Stipe 2.8–4.2 cm long, 0.3–0.4 cm thick, cylindrical, equal or attenuate at the base, greyish yellow (# b 6 b 09 a); stipe context changing to slightly desaturated orange (# b 99 b 7 e) when injured. The odor and taste were not distinctive. Basidiospores [100 / 2 / 2] (6.1 –) 6.5–8.3 (– 8.6) × (4.3 –) 4.5–5.8 (– 6.5) μm, (N = 100, Q = 1.10–1.77, Q m = 1.45 ± 0.15), av. 7.36 ± 0.65 × 5.10 ± 0.44 μm, in face view, the spores are broadly to subbroadly fusiform, while in lateral view, they exhibit a profile dominated by a suprahilar depression, hyaline, smooth, basidiospores scatter plot, see Fig. 6. Basidia 21–35 × 7–10 μm (N = 20), av. 28.5 ± 3.3 × 8.5 ± 0.9 μm, mostly 4 - spored, rarely 2 - spored, sterigmata 1.7–5.3 μm long, clavate to narrowly clavate, sometimes with basal clamp connections. Subhymenium consisting of thin and hyaline elements, 13–22 μm wide, with 2–3 layers of ovoid, subglobose, broadly fusiform, 1.7–11.0 × 1.4–4.1 μm, av. 5.1 ± 2.3 × 2.9 ± 0.8 μm. Hymenophoral trama regular, made up of inflated hyaline hyphae, 120–170 μm wide, some with clamp connections, narrowly cylindrical hyphal elements, 4–20 μm wide. Pleurocystidia 14–24 × 3–5 μm, av. 18.8 ± 2.3 × 3.8 ± 0.4 μm, narrowly cylindrical, narrowly clavate or flexuose, thin-walled. Cheilocystidia 8–24 × 2–5 μm, av. 17.7 ± 3.4 × 3.7 ± 0.6 μm, narrowly cylindrical, narrowly clavate or flexuose, thin-walled, occasionally mucronate on the apex. Pileipellis a subcutis composed of 2–7 μm wide hyphae, almost cylindrical, abundant pileocystidia present on the pileus, 5–31 × 2–5 µm, av. 19.8 ± 10.3 × 3.5 ± 0.6 µm, fusiform, narrowly cylindrical or flexuose, irregular, with mucronate apex, thin-walled, some with clamp connections. Stipitipellis composed of appressed, parallel, thin-walled, smooth, 2–5 µm wide hyphae, stipe surface bears abundant easily detachable pigment cells. Clamp connections are present at some septa. Habitat. Single to scattered on soil in coniferous forest, from August to October. Additional species examined. China, Yunnan Province, Dali City, Jianchuan County, elev. 2,180 m, 7 September 2024, Rui-Yu Li, T 86 (HKAS 150788, paratype). Notes. Compared with the species with orange to brown pileus and a slender stipe, L. edulis, L. aemiliae Consiglio, and L. lixivium are similar to the new species. Lyophyllum edulis has a larger pileus (3–8 cm vs 1.4–1.8 cm), globose to subglobose basidiospores (av. 5.81 × 5.47 μm, Q m = 1.11 vs 7.36 × 5.10 μm, Q m = 1.45); additionally, L. hemigaleatum possesses abundant cystidia on the pileus surface, a feature not reported in L. edulis (Tang et al. 2025 a). Lyophyllum aemiliae, originally described from Italy, is distinguished by a pileus with a wavy-lobed margin, slight streaking and irregular blackish-brown patches, in addition to a parallel pileipellis (Melis et al. 2023). Lyophyllum lixivium can be distinguished by its pileus developing a distinct umbo at maturity, and its relatively long stipe (10–14 cm vs 2.8–4.2 cm) with a slightly swollen base; basidiospores are broadly lacrimoid and relatively small (4.4–6.5 × 3.7–5.8 μm vs 6.5–8.3 × 4.5–5.8 μm), pileipellis is composed of parallel hyphae (Lyu et al. 2024). In multi-locus phylogenetic analysis, the new species is closely related to Lyophyllum semitale and L. deliberatum (Britzelm.) Kreisel. Lyophyllum semitale was originally described from Sweden and has a leaden-grey pileus that is larger than L. hemigaleatum (2.5 cm vs 1.4–1.8 cm) and a white stipe; this species is lignicolous and grows saprophytically on decaying wood (Kühner 1938). In contrast, L. hemigaleatum bears orange-toned basidiomata and occurs terrestrially on mineral soil within coniferous forests, the ITS sequence differences between L. hemigaleatum (HKAS 150782, type) and L. semitale (IE-BSG-HC 85 / 13) were 3.03 % (16 / 528). Lyophyllum subalpinarum from China has a greyish-yellow to brown pileus and is darker at the centre, and ITS sequence differences between L. hemigaleatum (HKAS 150782) and L. subalpinarum (HMJAU 63447) were 2.46 % (13 / 529). Lyophyllum deliberatum was originally described in Europe; the pileus is brown to olive, and the stipe enlarged toward the base, and ITS sequence differences between L. hemigaleatum (HKAS 150782) and L. deliberatum (V. 15032) were 3.02 % (16 / 529).
Institution: Dali University
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7166314097