Skeletocutis cangshanensis B.K. Cui & Shun Liu

Facesoffungi Number: FoF 10674

 

Skeletocutis cangshanensis B.K. Cui & Shun Liu, Index Fungorum Number: IF559465

Description

Fruiting body basidiocarps annual, resupinate, not easily separated from substrate, soft leathery, without odor or taste when fresh, becoming corky upon drying, up to 8.5 cm long, 3.5 cm wide, and 1 mm thick at center. Pore surface white when fresh, becoming white to buff-yellow upon drying; pores circular to angular, 7–10 per mm; dissepiments thick, entire. Subiculum white, corky, up to 0.2 mm thick. Tubes darker than poroid surface, corky, up to 0.5 mm long. Hyphal Structure hyphal system dimitic; generative hyphae with clamp connections, hyaline, thin- to slightly thick-walled, dominant at dissepiment edge; skeletal hyphae thick-walled with a wide to narrow lumen; IKI–, CB–, unchanged in KOH. Subiculum generative hyphae frequent, hyaline, thin- to slightly thick-walled, rarely branched and bearing fine crystals, 1.5–2.8 μm in diameter; skeletal hyphae dominant, thick-walled with a narrow lumen, flexuous, unbranched, interwoven, 2–3.5 μm in diameter. Tubes generative hyphae frequent, thin-walled, frequently branched, usually covered by fine crystals, sharply pointed encrustations, especially at dissepiment edge, 1.5–2.5 μm in diameter; skeletal hyphae dominant, thick-walled with a wide to narrow lumen, occasionally branched, subparallel along the tubes, not agglutinated, 2–3 μm in diameter. Dissepiment edge dimitic with smooth skeletal hyphae, and dominant winding, encrusted generative hyphae. Cystidia absent, cystidioles abundant, bottle-shaped, with a conical apex, 7.5–17 × 3.2–4.7 μm. Basidia clavate, with a basal clamp connection and four sterigmata, 9.6–13.5 × 3.2–4.7 μm; basidioles in shape similar to basidia, but slightly smaller. Spores basidiospores cylindrical, hyaline, thin-walled, smooth, IKI–, CB–, (2.6–)2.7–3.5 × 0.8–1.5 μm, L = 3.02 μm, W = 1.02 μm, Q = 2.76–3.23(n = 90/3).

Material examined: CHINA. Yunnan Province, Dali, Cangshan Park, on angiosperm stump, 4 November 2019, Cui 17978 (holotype, BJFC); on fallen angiosperm branch, 4 November 2019, Cui 17990, 17994 (paratypes, BJFC).

Distribution: CHINA. Yunnan Province, Dali, Cangshan Park

Sequence data: Cui 17978 (ITS: MZ327279; nLSU: MZ348535), Cui 17990 (ITS: MZ327280; nLSU: MZ348536), Cui 17994 (ITS: MZ327281; nLSU: MZ348537)

Notes: Skeletocutis cangshanensis is characterized by its white pore surface when fresh, white to buff-yellow upon drying, small and circular to angular pores (7–10 per mm), and cylindrical basidiospores (2.7–3.5 × 0.8–1.5 μm). In the phylogenetic tree, the three specimens of Skeletocutis cangshanensis formed a highly supported lineage, and grouped together with S. bambusicola L.W. Zhou & W.M. Qin. Morphologically, both S. cangshanensis and S. bambusicola have similar pores, but S. bambusicola differs by having wider basidiospores (2.5–3 ×1.5–2 μm) and growth on Bambusa (Zhou and Qin 2012). Skeletocutis lepida A. Korhonen & Miettinen, S. mopanshanensis C.L. Zhao and S. yunnanensis L.S. Bian, C.L. Zhao & F. Wu were also discovered from Yunnan Province. Skeletocutis lepida differs from the new species by having narrower basidiospores (2.9–3 × 0.5–0.6 μm; Korhonen et al. 2018); S. mopanshanensis differs by having larger pores (4–5 per mm) and basidiospores (4.7–6.6 × 3.2–4.5 μm; Wu et al. 2017); S. yunnanensis differs by having larger pores (5–6 per mm) and basidiospores (3.4–4.5 × 1–1.2 μm; Bian et al. 2016).

Species