Hygrophorus atropurpureus L. P. Tang & H. Y. Huang sp. nov.
Fig. 2
Chinese name.
紫黑蜡伞.
Diagnosis.
Hygrophorus atropurpureus is distinguished from the closest relative, H. arbustivus by its smaller basidiomata, a blackish-purple pileus, scattered to gregarious habit and occurrence in the subalpine belt (2000–2700 m elevation) of Yunnan Province, south-western China.
Etymology.
The species epithet “ atropurpureus ” combines the Latin “ atro- ” (dark) and “ purpureus ” (purple), referring to the characteristic dark purple to purplish-black colouration of the pileus.
Type.
China • Yunnan Province: Eryuan County (洱源县), Ma’er Mountain (马耳山), in mixed broadleaf-conifer forests, dominated by Quercus aquifolioides, Quercus spp., Pinus armandii, P. densata, Rhododendron decorum and Vaccinium fragile, 26°5'25"N, 100°8'45"E, elev. 2700 m, 4 October 2020, L. P. Tang 3516 (holotype: MHKMU TLP-3516, isotype: HMAS 354461; GenBank Acc. Nos.: ITS = PX 868434, nrLSU = PX 868336, tef 1 - α = PX 907458).
Description.
Basidiomata small to medium-sized, rather fragile. Pileus 2–4 cm diam., convex with an incurved margin when young, expanding to plane with a depressed centre; margin often wavy and uplifted with age. Colour purplish-black (12 F 4–5) when young, fading to purple, dark purple to blackish-purple (12 D 3–4) when mature, margin light purple (12 B 2–3). Surface dry, covered with tomentose squamules. Context white (1 A 1). Lamellae up to 0.3 cm wide, decurrent, subdistant, with 35–50 full lamellae per pileus; lamellulae numerous, narrowed; colour white (1 A 1). Stipe 3–4 cm long, 0.5–0.8 cm diam., central, cylindrical, equal; surface reddish-purple (12 B 2–3); context firm, white (1 A 1). Basal mycelium white. Odour not distinctive. Taste unrecorded.
Basidiospores [60 / 3 / 2] 6.8–8.5 (– 9) × 4–5 (– 6) μm, Q = 1.45–1.86 (– 2.13), Q m = 1.66 ± 0.16, ellipsoid to oblong, smooth, thin-walled, hyaline, inamyloid, with a distinct hilar appendix. Basidia 30–50 × 7–10 μm, clavate, slender, thin-walled, 4 - sterigmate; sterigmata up to 4 μm long. Hymenophoral trama slightly divergent, non-gelatinised, composed of cylindrical hyphae 3–15 μm diam. and inflated elements up to 25 μm diam., thin-walled, hyaline. Subhymenial layer next to hymenium, not gelatinised, composed of short cylindrical to irregularly-shaped elements 7–40 × 4–7 μm, thin-walled, hyaline. Pileipellis an ixotrichoderm, gelatinised, consisting of narrow, interwoven, thin-walled, hyphae 2–6 μm diam., branched or unbranched. Pileal trama of dense, thin-walled hyphae 6–18 μm diam. Stipitipellis a cutis, hyphae 3–5 μm diam., thin-walled. Stipititrama of parallel, thin-walled hyphae 3–21 μm diam. Mycelial hyphae 1.5–5 μm diam., smooth. Clamp connections present in all tissues.
Known distribution.
Yunnan Province, China.
Habit and habitat.
Scattered to gregarious in mixed broadleaf-conifer forests, dominated by Pinus armandii, P. densata, Quercus aquifolioides, Quercus spp., Rhododendron decorum and Vaccinium fragile, elev. 2000–2700 m; fruiting in autumn (September – October).
Additional material examined.
China • Yunnan Province: Kunming City (昆明市), Kunming Institute of Botany, Chinese Academy of Sciences, elev. 2000 m, 25 September 2005, Z. W. Ge 929 (paratype: HKAS 49694).
Notes.
Phylogenetically, H. atropurpureus forms a well-supported monophyletic clade, together with an undescribed sister taxon labelled H. aff. atropurpureus from Yunnan Province and the European species H. arbustivus Fr. However, H. arbustivus is phylogenetically more distant to the two Chinese species and differs in its ochraceous-brown pileus and its occurrence in low-elevation European habitats (<1500 m), where it is likely associated with Quercus (Candusso 1997; this study). Hygrophorus aff. atropurpureus is currently known from a single collection with suboptimal material; no obvious morphological differences from H. atropurpureus have been observed and a formal comparison will be deferred until additional specimens become available.
Publication Date: 2026-06-17