Hydnellum ailaoense L. Lei & Q. Zhao, 2023

Lei, Lei, Luangharn, Thatsanee, Yu, Feng-Ming, Li, Wei-Jiao, Li, Wen-Chun & Zhao, Qi, 2023, A novel hydnoid species of Hydnellum (Bankeraceae, Thelephorales) from southwest China, Phytotaxa 600 (5), pp. 291-300 : 295-297

Hydnellum ailaoense L. Lei & Q. Zhao , sp. nov. ( Figs. 2 , 3 , 4 )

Index Fungorum number: IF900404; Facesoffungi number: FoF14128

Etymology:—The specificity “ ailaoense ” refers to the location where the type specimen was collected.

Diagnosis:—Differs from other Hydnellum species by pileus uplifted squamosa, margin brownish beige to grey, the tuberculi of basidiospores usually isolated or grouped in 2 or more, and abundant-septate of the hyphae in context.

Basidiocarp annual, solitary to gregarious, soft texture when fresh, and light in weight when dried. Pileus 4–7.5 cm diam, irregular circular, first broadly convex, becoming planar or center slightly depressed, margin incurved and occasionally incised with age, light brown (6D7) to brown (7E8), azonate, velutinate occasionally lobed with age, uplifted squamosa, tomentose at the early stage, becoming cuticle, crowded, gradually sparse and smooth toward the margin, dark brown (7F7) to black, margin of pileus grey (5C1) to brownish beige (6E3). Spines up to 1.5 mm long when dried, brown (7E8), 6–10 per mm, brown (7E5) at the base, white at the tip, gradually sparse towards the base of the stipe, and easy to fall off. Stipe 4–6.5 × 1–1.5cm, club-shaped, subeccentric to eccentric, light brown (6D5), brown (7E5), dark brown (7F8) to black, scabrous, denser spines on the surface, and gradually sparse to downward.

Basidiospores 5.5–7 (–7.5) × 4.5–6 (–6.5) μm, L m = 6.3 μm, W m = 5.2 μm, Q = 1.09–1.33 (n = 60/2), Q m = 1.21 ± 0.08, subglobose, broadly elliptical to oval, brown, CB –, IKI –, irregular, with warty convexity, and tuberculi usually isolated or grouped in 2 or more, up to 1.0 µm. Basidia (32–) 35–51 (–56) × 5–9 µm, clavate, 4-spored, sterigmata 3–5 µm long, basal septa lacking clamps, cystidia and cystidioles absent. Mycelial structure: monotypic hyphal system, generative mycelium, with simple septa, and olive tissues in KOH, CB –, IKI –. Context: mostly 5–11 μm diam, usually thin-walled, hyaline, occasional branched, abundant-septate, and regularly to sub-regularly arranged. Spines: 2–5 μm diam, usually hyaline, thin-walled, frequently branched, more or less parallel along the spines, simple septate with straight.

Habitat:—Solitary, growing on the ground dominated by Fagaceae and Pinaceae forests.

Material examined:— CHINA, Yunnan Province, Nanhua county, Ailao Mountains , 24°54′0.122N, 100°47′24.599′′E, alt. 2498 m, 17 August 2021, Lei Lei, ALS16 ( HKAS 125553 , holotype) ; ibid., alt. 2337 m., 18 August 2021, Lei Lei, ALS236 ( HKAS 125554 ) .

Notes: — Hydnellum ailaoense is characterized by its light brown to brown pileus, dark brown to black uplifted squamosa, margin brownish beige to grey, basidiospores subglobose, broadly elliptical to oval, the tuberculi usually isolated or grouped in 2 or more, and abundant-septate of the hyphae in context. Morphologically, H. ailaoense resembles H. underwoodii in azonate pileal surface, spiny stipe, similar-sized basidiospores, and olive tissues in KOH. However, H. ailaoense can be easily distinguished from H. underwoodii by its darker colour of basidiocarp, the relatively smooth margin of the pileus, finer hyphae of pileus (5–11 μm vs. up to 20 μm) and spines (2–5 μm vs. up to 9 μm). The scale size and arrangement of the former are irregular, while the scales of the latter are very small (1–2 mm) and subzonately arranged ( Banker 1906, Baird et al. 2013). Phylogenetically, our new taxa Hydnellum ailaoense (HKAS 125553) forms a well-supported clade, and is grouped as a sister clade to H. underwoodii with 100% ML bootstrap support and 1.00 Bayesian probability in nLSU-ITS multi-gene phylogeny ( Fig. 1 ).

Figures

FIGURE 1. Maximum likelihood tree based on the combined nLSU and ITS dataset, showing the phylogenetic position of H. ailaoense. Bootstrap proportions (MLBP) equal to or above 75%, and equal to or above 0.90 proportions (BIPP) are shown above the branches of the phylogenetic tree. The newly generated sequences are shown in bold red.

FIGURE 2. Hydnellum ailaoense (HKAS 125553, holotype). a–d Typical mature basidiocarps. Scale bars: a–d = 5 cm.

FIGURE 3. Hydnellum ailaoense (HKAS 125553, holotype). a Section of hymenophore trama with basidia. b Hyphae from pileus context. c Basidiospores. Scale bars: a, b = 40 μm, c = 10 μm.

FIGURE 4. Hydnellum ailaoense (HKAS 125553, holotype). a-d Appearance of basidiospores were photographed using SEM. Scale bars: a, b = 2 μm, c, d = 1 μm.