Skeletocutis yunnanensis L.S. Bian, C.L. Zhao & F. Wu, 2016

Bian, Lu-Sen, Zhao, Chang-Lin & Wu, Fang, 2016, A new species of Skeletocutis (Polyporales, Basidiomycota) from Yunnan of China, Phytotaxa 270 (4), pp. 267-276 : 270-272

Skeletocutis yunnanensis L.S. Bian, C.L. Zhao & F. Wu , sp. nov. ( Figs. 2 , 3 )

MycoBank: MB 816294

Skeletocutis yunnanensis is characterized by resupinate, white to buff pore surface, almost lacking sterile margin when mature, angular pores mostly 5–6 per mm with entire mouths, a dimitic hyphal structure throughout all parts of fruiting body, generative hyphae in subiculum and trama covered by fine crystals, skeletal hyphae unchanged in KOH, allantoid basidiospores measured as 3.5–4.5 × 1.0–1.2 μm, and growth on angiosperm wood.

Type. — CHINA. Yunnan Province, Dali, Binchuan County, Jizushan Forest Park, on fallen angiosperm branch in temperate forest, 30 Aug 2015, Fang Wu (Holotype, BJFC019813!).

Etymology.— Yunnanensis (Lat.) : refers to the locality of the type species.

Fruiting body.—Basidiocarps annual, resupinate, very difficult to separate from substrate, soft leathery and without odour or taste when fresh, becoming soft corky to fragile upon drying, up to 5 cm long, 2 cm wide, and 1.4 mm thick at centre. Pore surface white when fresh, pale buff when bruised, cream to buff upon drying, bruised part becoming buff-yellow when dry; margin distinct when juvenile, consistent white, up to 2 mm, narrow to almost lacking when mature; pores angular, freely arranged, mostly 5–6 per mm, some part irregular, 3–4 per mm; dissepiments thin, entire. Subiculum white, soft corky, up to 0.4 mm thick. Tubes concolorous with poroid surface, soft fragile, up to 1 mm long.

Hyphal structure. —Hyphal system dimitic, generative hyphae with clamp connections, hyaline, thin-walled; skeletal hyphae thick-walled with a narrow lumen to subsolid; all hyphae IKI–, CB–, unchanged in KOH.

Subiculum. —Generative hyphae frequent, hyaline, thin- to slightly thick-walled, occasionally branched and bearing fine crystals, 1.5–2.5 μm in diam.; skeletal hyphae dominant, thick-walled, flexuous, unbranched, interwoven, 1.8–3.2 μm in diam.

Tubes. —Generative hyphae frequent, thin- to slightly thick-walled, occasionally branched, usually covered by fine, sharp-pointed encrustations, especially at dissepiment edge, 1.5–2.5 μm in diam.; skeletal hyphae dominant, thick-walled with a narrow lumen to subsolid, unbranched, subparallel along the tubes, not agglutinated, 1.8–3 μm in diam. Dissepiment edge with scanty smooth skeletal hyphae and abundant, fairly straight, encrusted generative hyphae. Cystidia absent, cystidioles abundant, bottle-shaped, with a conical apex, almost as size as basidia, 8–10 × 3–4 μm; Basidia clavate, with a basal clamp connection and four sterigmata, 8–12 × 3–4.5 μm; basidioles infrequent, in shape similar to basidia, but slightly smaller.

Spores. —Basidiospores mostly allantoid, hyaline, thin-walled, smooth, usually bearing one to three small guttules, CB–, IKI–, (3.2–)3.5–4.5 × 1.0–1.2(–1.5) μm, L = 3.99 μm, W = 1.08 μm, Q = 3.54–3.83 (n = 60/2).

Additional specimen examined (Paratype).— CHINA. Yunnan Province, Dali, Binchuan County, Jizushan Forest Park, on rotten angiosperm wood in temperate forest, 30 Aug 2015, Fang Wu (BJFC019816!)

Figures

FIGURE 2. A fruiting body of Skeletocutis yunnanensis (BJFC019816). Bar: 1 cm

FIGURE 3. Microscopic structures of Skeletocutis yunnanensis (Holotype). a. Basidiospores. b. Basidia, cystidioles and basidioles. c. A section of dissepiment edge. d. Subicular hyphae. Bars: a = 5 μm; b–d = 10 μm