Rigidotubus tephroleucus J. Song, Y.C. Dai & B.K. Cui, 2018

Song, Jie, Xing, Jia-Hui, Ji, Xing, Sun, Yi-Fei, Cui, Bao-Kai & Dai, Yu-Cheng, 2018, Rigidotubus tephroleucus gen. et sp. nov. (Cystostereaceae, Agaricales) evidenced by morphological characters and phylogenetic analyses, Phytotaxa 333 (2), pp. 259-266 : 263

Rigidotubus tephroleucus J. Song, Y.C. Dai & B.K. Cui , sp. nov. ( Fig. 3 )

MycoBank no.: MB 823703

Diagnosis— Rigidotubus tephroleucus is characterized by resupinate, tough basidiomata, grayish white pore surface, white sterile margin, a monomitic hyphal system with clamped generative hyphae, ovoid to ellipsoid and thin-walled basidiospores, 3.5–4.5 × 2.3–3 μm.

Type — CHINA. Hainan Province, Baoting County, Qixianling Forest Park, on angiosperm stump, 20 November 2015, Cui 13717 (holotype, BJFC! isotype in IFP!).

Etymology— Tephroleucus (Lat.) : referring to the grayish white pore surface.

Fruiting body —Basidiomata annual, resupinate, adnate, tough, without odor or taste when fresh, up to 20 cm long, 5 cm wide and 3 mm thick at centre. Pore surface grayish white when dry; pores round to angular, 2–4 per mm; dissepiments thin, entire to slightly lacerate; margin sterile, irregular, white, up to 3 mm wide. Subiculum white to buff when dry, membranous, up to 0.5 mm thick. Tubes concolorous with pore surface, tough, up to 2.5 mm long.

Hyphal structure —Hyphal system monomitic; generative hyphae with clamp connections, all hyphae IKI–, CB–; tissues unchanged in KOH.

Subiculum —Generative hyphae hyaline, thin-walled, frequently branched, interwoven, 1–2 μm in diam.

Tubes —Generative hyphae hyaline, thin-walled, frequently branched, 0.5–2 μm in diam. Cystidia and cystidioles absent. Basidia clavate, with four sterigmata and a basal clamp connection, 8–12 × 3–5 μm in diam; basidioles dominant, similar in shape to basidia but smaller.

Spores —Basidiospores ovoid to ellipsoid, thin-walled, hyaline, smooth, IKI–, CB–, 3.5–4.5 × 2.3–3 μm, L = 3.96 μm, W = 2.6 μm, Q = 1.49–1.52 (n=60/2).

Rot type —A white rot.

Additional specimen examined — CHINA. Hainan Province, Qiongzhong County, Limushan Forest Park, on fallen angiosperm trunk, 18 November 2015, Cui 13653 (paratype, BJFC!).

Figures

FIGURE 3. Microscopic structures of Rigidotubus tephroleucus (draw from the holotype). a — Basidiospores. b — Basidia. c — Basidioles. d — Hyphae from trama. e — Hyphae from subiculum. Scale bars: a–e = 10 μm.