Ganoderma yunnanense J. He and S.H. Li
MycoBank number: MB845722
Basidiomata: annual, centrally to laterally stipitate, hard corky. Pileus: single, flabelliform to reniform or suborbicular, projecting up to 9 cm, 6.5 cm wide and 0.5 cm thick at base. Pileus surface reddish brown (10F8) to violet brown (11F8), weakly to strongly laccate, glossy, with shallowly concentric furrows and radial rugose. Margin: pale yellow (3B2) to concolorous, entire, acute, incurved when dry. Context: up to 0.3 cm thick, homogeneous, white to cream (1B2), fibrous, corky, without black melanoid lines. Tubes: 0.1–0.2 cm long, concolorous with the base of the context, corky, unstratified. Pores: 4–6 per mm, round to angular, dissepiments thick, entire; pore surface white when fresh, lead grey (3B1) when bruising and drying. Stipe: 15.0–17.5 × 1.0–2.0 cm, dorsally lateral to nearly dorsal, cylindrical and solid, concolorous with pileus surface, strongly laccate, fibrous to woody. Hyphal system trimitic: generative hyphae 2.0–3.0 μm in diameter, colorless, thin-walled, with clamps connections; skeletal hyphae 2.0–6.0 μm in diameter, subthick-walled to solid, non-septate, arboriform with few branches, colorless to pale yellow; binding hyphae 1.5–3.0 μm in diameter, thick-walled, frequently branched and flexuous, colorless, scarce; all the hyphae IKI–, CB+; tissues darkening in KOH. Pileipellis: a crustohymeniderm, composed of a palisade of vertical, cells 23–40 × 6–9 μm, slightly thick-walled, clavate to cylindrical, slightly inflated, straw yellow to golden-yellow, granulations in the apex, moderately clavate to cylindrical amyloid at maturity.
Basidiospores: broadly ellipsoid to ellipsoid, apex not obviously truncated, with apical germ pore, yellowish to pale yellowish brown, IKI–, CB+, inamyloid; double-walled with distinctly thick walls, exospore wall smooth, endospore walls with inter-wall pillars; (40/2/2) (8.0) 9.0–10.7–12.0 (12.5) × 7.0–7.6–8.0 (8.5) μm, Q = (1.10) 1.25–1.41–1.55 (1.60), Qm = 1.41 ± 0.12 (including myxosporium). Basidia: widely clavate to barrel-shaped, colorless, with a clamp connection and four sterigmata, thin-walled, 15–18 × 8–11 μm; basidioles clavate, colorless, thin-walled, 10–14 × 6–9 μm.
Specimens examined: China, Yunnan Province., Puer City, Jingdong Co-unty, Ailao Mountains (101°01′29″E, 24°30′03 N), on a rotten broad-leaved tree, alt. 2,326 m, Jun He, 4 August 2019, L4812 (HKAS 123769).
Notes: Our multi-locus phylogenetic analyses show that Ganoderma yunnanense is sister to G. ovisporum with high statistical support (84% ML/0.98 PP, Figure 3), and together they group with G. sandunense and G. magniporum (Zhao et al., 1984; Hapuarachchi et al., 2019; Yang et al., 2022). Ganoderma yunnanense resembles G. ovisporum in having reddish-brown pileus and broadly ellipsoid basidiospores. However, G. ovisporum has heterogeneous context, shorter pileipellis cells (18–29 × 6–11 μm) and larger basidiospores (12.5–15.5 × 9.0–11.5 μm, Yang et al., 2022). Moreover, Ganoderma sandunens has larger basidiospores (10.8–15.7 × 8.6–12.5 μm) and thicker context than those of G. yunnanense (Hapuarachchi et al., 2019; Yang et al., 2022). Ganoderma magniporum can be easily distinguished from G. yunnanense by the larger pores (2–2.5 per mm), black-brown to black pileus surface and ovoid basidiospores with truncated apex (8.7–10.4 × 5.2–7.0 μm, Zhao et al., 1984). Morphologically, G. yunnanense resembles G. leucocontextum by white pore surface and context. However, G. leucocontextum has red to red brown pileus surface, white to yellowish margin, shorter stipe (5–10 cm) and broadly ellipsoid basidiospores with truncated apex (8.0–12.5 × 5.5–9.0 μm, Li et al., 2015). Among the species in the G. lucidum complex, G. yunnanense looks very similar to G. tsugae and G. weixiense morphologically, although they can be easily distinguished by phylogenetic analyses and ecological distribution (Murrill, 1902; Ye et al., 2019). In addition, G. yunnanense also shares similarities with G. dianzhongense but the latter has dark-brown to putty context and wider pileipellis cells than those of G. yunnanense. The nucleotide comparison of ITS sequences of G. yunnanense and G. dianzhongense revealed 26 bp (26/614 bp, 4.23%) nucleotides differences (He et al., 2021).