Fomitiporia robustiformis Jian Chen, Yuan Yuan, K. Y. Luo, Y. C. Dai & Vlasák, 2025

Chen, Jian, Vlasák, Josef, Luo, Kai-Yue & Yuan, Yuan, 2025, Three new species of Fomitiporia (Hymenochaetales, Basidiomycota) from tropical dry forests in Ecuador and Peru, MycoKeys 118, pp. 267-287 : 267-287

Fomitiporia robustiformis Jian Chen, Yuan Yuan, K. Y. Luo, Y. C. Dai & Vlasák sp. nov.

Figs 2 , 3

Diagnosis.

Fomitiporia robustiformis is closely related to F. texana (Murrill) Nuss and F. deserticola Vlasák , but F. texana differs from F. robustiformis by the presence of hymenial setae and cystidioles, larger basidiospores (7–9 × 6.5–9 µm vs. 5–6.4 × 4.7–6.1 µm). F. deserticola is distinguished from F. robustiformis by the presence of abundant cystidioles and larger basidiospores (6–7.5 × 5.5–7 µm vs. 5–6.4 × 4.7–6.1 µm).

Holotype.

Ecuador • Arenillas , dry tropical forest, on living Acacia sp. , 17.II.2024, leg J. Vlasák, JV 2402/8 ( BJFC 053711 ).

Etymology.

Robustiformis (Lat.) refers to a new species characterized by robust basidiomata.

Description.

Basidiomata perennial, pileate, inseparable, sessile, without distinctive odor or taste when fresh, woody hard in consistency, light in weight when dry; pilei ungulate, fan-shaped, projecting up to 5 cm, 5 cm wide, and 3 cm thick at base; pileal surface brown, sometimes greenish from algae, glabrous; margin broad and rounded. Pore surface pale mouse-gray when fresh, becoming yellowish brown when dry, not glossy; sterile margin brown, up to 1 mm wide; pores circular to angular, 6–7 per mm; dissepiments thin, entire. Context yellow-brown, woody hard, up to 7 mm thick; tubes pale gray to yellow-brown, paler than pore surface, woody hard, up to 2 cm long, annual layers indistinct.

Hyphal structure. Hyphal system dimitic, generative hyphae simple septate; all hyphae IKI -, CB -; tissue becoming dark brown in KOH.

Context. Generative hyphae frequent, pale yellow, slightly thick-walled, rarely branched, frequently septate, 3–3.5 µm in diam; skeletal hyphae dominant, yellowish brown, thick-walled, unbranched, more or less flexuous, interwoven, 3–4.5 µm in diam.

Tubes. Generative hyphae pale yellowish, slightly thick-walled, rarely branched, frequently septate, 3–3.5 µm in diam; skeletal hyphae dominant, yellowish, thick-walled, unbranched, more or less straight, parallel along the tubes, 3–4.5 µm in diam. Hymenial setae absent; cystidioles present, fusoid, hyaline, thin-walled, 14–18 × 2.5–3.5 μm; basidia clavate, with four sterigmata and a simple septum at the base, 10–18 × 6–7.5 µm; basidioles dominant in hymenium, in shape similar to basidia, but slightly smaller.

Basidiospores globose, hyaline, thick-walled, smooth, some with a guttule, IKI [+], CB +, (4.4 -) 5–6.4 (- 7.1) × (4.4 -) 4.7–6.1 (- 6.9) µm, L = 5.66 µm, W = 5.39 µm, Q = 1.05 (n = 30 / 1).

Type of rot. White rot.

Additional specimen (paratype) examined.

Peru • Chongoyape , dry tropical forest, on a dead branch of a living angiosperm tree, 21.I.2025, leg J. Vlasák Jr., JV 2501/5-J .

Figures

Figure 2. Basidiomata of Fomitiporia robustiformis (holotype, JV 2402 / 8). Scale bar: 1 cm.

Figure 3. Microscopic structures of Fomitiporia robustiformis (Holotype, JV 2402 / 8) a basidiospores b hyphae from context c basidia and basidioles d cystidioles e hyphae from the tube trama.