Fulvifomes fragilis Jian Chen, Yuan Yuan, K. Y. Luo, Y. C. Dai & Vlasák, 2025

Chen, Jian, Yuan, Yuan, Luo, Kai-Yue & Vlasák, Josef, 2025, Two new species of Fulvifomes (Hymenochaetales, Basidiomycota) from South America, MycoKeys 119, pp. 263-279 : 263-279

Fulvifomes fragilis Jian Chen, Yuan Yuan, K. Y. Luo, Y. C. Dai & Vlasák sp. nov.

Figs 4 , 5

Diagnosis.

Fulvifomes fragilis is related to F. luteoumbrinus (Romell) Y. C. Dai & Vlasák , but F. luteoumbrinus differs from F. fragilis by a monomitic hyphal system and larger basidiospores (5.0–6.0 × 4.0–5.5 µm vs. 3.9–5.1 × 3–3.7 µm).

Holotype.

Ecuador. • Macará, Reserva Jorupe , dry tropical forest, altitude 650 m, on roots of rotten angiosperm tree, 21.II.2024, leg J. Vlasák Jr., JV 2402/50-J-1 ( BJFC 053708-1 ).

Etymology.

Fragilis (Lat.): refers to the species having brittle basidiomata when dry.

Description.

Basidiomata annual, pileate, imbricate, without distinctive odor or taste, and woody hard to brickle when dry. Pilei sessile, projecting up to 7 cm and 11 cm wide and 8 mm thick at base. Pileal surface curry yellow to yellowish brown when dry, rough; pileal margin yellowish brown, narrow. Pore surface yellow, rugged; sterile margin distinct, yellow, up to 4 mm wide; pores circular to elliptical, 5–6 per mm; dissepiments thick, entire. Context lemon yellow, woody hard, up to 6 mm thick. Tubes concolorous with context, woody hard, up to 0.5 mm long.

Hyphal structure.

Hyphal system dimitic in trama and context; generative hyphae simple septate; tissue becoming blackish brown in KOH.

Context.

Generative hyphae pale yellow, thick-walled, occasionally branched, frequently simple septate, 3–4 µm in diameter; skeletal hyphae dominant, yellowish to golden yellow, thick-walled, unbranched, aseptate, more or less straight, regularly arranged, 3–4 µm in diameter.

Tubes.

Generative hyphae pale yellow, thick-walled, rarely branched, frequently simple septate, 2.5–4.5 µm in diameter; skeletal hyphae frequent, yellowish to golden yellow, thick-walled with a narrow to wide lumen, unbranched, aseptate, more or less straight, subparallel along tubes, 2.5–4.5 µm in diameter. Setae or setal hyphae absent; cystidioles absent; basidia clavate to barrel-shaped, with four sterigmata and a simple basal septum, 11–14 × 5–6 µm; basidioles in shape similar to basidia, slightly smaller than basidia.

Basidiospores broadly ellipsoid, yellowish brown, thick-walled, smooth, some collapsed, IKI –, CB –, 3.9–5.1 × (2.9 –) 3–3.7 (– 3.8) µm, L = 4.38 µm, W = 3.38 µm, Q = 1.30–1.32 (n = 60 / 2).

Type of rot.

White rot.

Additional specimen examined

(paratype). Ecuador. • Macará, Reserva Jorupe , dry tropical forest, altitude 650 m, on roots of rotten angiosperm tree, 21.II.2024, leg J. Vlasák Jr., JV 2402/50-J-2 ( BJFC 053708-2 ) .

Figures

Figure 4. Basidiomata of Fulvifomes fragilis (Holotype, JV 2402 / 50 J- 1). Scale bar: 1 cm.

Figure 5. Microscopic structures of Fulvifomes fragilis (holotype, JV 2402 / 50 - J- 1). a. Basidiospores; b. Basidia and basidioles; c. Hyphae from context; d. Hyphae from tube trama.