Fomes hengduanensis Y.C. Dai, Chao G. Wang & Y.J. Cui, 2024

Cui, Yu-Jin, Liu, Hong-Gao, Dai, Yu-Cheng & Wang, Chao-Ge, 2024, A new species of Fomes (Polyporaceae, Basidiomycota) from southwestern China, Phytotaxa 661 (3), pp. 282-292 : 286-288

Fomes hengduanensis Y.C. Dai, Chao G. Wang & Y.J. Cui , sp. nov. ( Figs. 2, 3 )

MycoBank no.—MB854092

Etymology:— Hengduanensis (Lat.): refers to the species growing in the Hengduan Mountains.

Holotype:— CHINA. Yunnan Province, Deqin County, Meili Snow Mts. Geopark, Mingyong Glacier , on dead branch of living tree of Quercus semecarpifolia , elev. 3200 m, N 28°27′23″, E 98°45′5″, 4 September 2021, Dai 22801 ( BJFC037374 ).

Description:— Basidiomata perennial, sessile, tough, woody to corky, without odor or taste when fresh, hard corky and significantly lighter in weight when dry. Pilei ungulate, projecting up to 1.8 cm, 3 cm wide and 2.5 cm thick at the base. Upper surface greyish brown, fawn to dark grey when fresh and dry, usually with a hard glabrous crust, concentrically zonate and sulcate; margin cinnamon to pale reddish brown, obtuse. Pore surface greyish brown when fresh and dry, slightly shiny; pores round, 3–5 per mm; pore mouth sometimes with white mycelium; dissepiments thick, entire; sterile margin distinct, pinkish buff, up to 6 mm wide. Context fawn to reddish brown, corky, up to 15 mm thick, with granular core developing at the upper part. Tubes slightly darker than pore surface, fawn, woody hard, up to 1 cm long.

Hyphal structure:—trimitic; generative hyphae bearing clamp connections; skeletal and binding hyphae IKI−, CB−; tissues darkening in KOH.

Structure of context:— generative hyphae infrequent, colorless, thin-walled, unbranched, straight, 2–4 μm in diam.; skeletal hyphae dominant, thick-walled with a medium to narrow lumen to subsolid, occasionally branched, straight, interwoven, 3–6 μm in diam., binding hyphae colorless, thick-walled with a medium lumen, frequently branched, flexuous, 1.5–3 μm in diam.

Structure of tubes:— generative hyphae infrequent, colorless, thin- to slightly thick-walled, unbranched, slightly flexuous, 2–5μm in diam.; skeletal hyphae dominant, colorless, thick-walled with a narrow lumen to subsolid, sometimes dichotomously branched, straight, interwoven, 2–5 μm in diam., binding hyphae thick-walled with a narrow lumen to subsolid, frequently branched, flexuous, 1.5–3 μm in diam. Cystidia absent; cystidioles clavate to fusoid, thin-walled, smooth, 18–21 × 7–9 μm. Basidia broadly barrel-shaped, with four sterigmata and a basal clamp connection, 15–16 × 13–14 µm; basidioles of similar shape to basidia but smaller.

Basidiospores cylindrical, colorless, thin- to slightly thick-walled, smooth, IKI−, CB−, (9–)9.5–14(–14.5) × 4.5–7 µm, L = 11.46 μm, W = 5.7 μm, Q = 1.99–2.12 (n=60/2).

Type of rot:—White rot.

Additional specimen examined (paratype):— CHINA. Yunnan Province, Chuxiong, Wuding County, Shizishan Natural Reserve, on dead tree of Quercus semecarpifolia , elev. 2600 m, 4 August 2019, Dai 20384 (BJFC032052).

Notes:— Fomes fomentarius and F. inzengae are very similar to F. hengduanensis , but F. fomentarius has longer basidiospores (15–21 × 5–7 µm vs. 9.5–14 × 4.5–7 µm, Tomšovský et al. 2023) as does F. inzengae (15–19 × 5–7 µm vs. 9.5–14 × 4.5–7 µm, Tomšovský et al. 2023).

Figures

FIGURE 3. Microscopic structures of Fomes hengduanensis (Dai 22801, holotype). a Basidiospores, b Basidia and Basidioles, c Cystidioles, d Hyphae from context, e Hyphae from trama. Scale bars: a–e = 10 μm.