Fulvifomes pannaensis S. Gunaseelan, M. Kaliyaperumal & K. Kezo sp. nov.

Index Fungorum number: IF 559690; MycoBank number: MB 559690;  Facesoffungi number: FoF 12671; Fig. 1

Etymology – The species epithet “pannaensis” referring to the region of basidiomata collected

Macromorphology – Basidiocarp perennial, solitary, pileate, sessile, light in weight, hard when dry. Pileus dimidiate, semi–circular, with no distinct crust, projecting up to 5.4 cm, 6.6 cm wide and 3.6 cm thick near the attachment. Pilear surface smooth to glabrous, weakly zonate, golden brown (5D7) to yellowish brown (5E8), pilei on maturation becoming rough, weakly cracked near attachment, greyish brown (6F3). Margin entire, round, velutinate, golden brown (5D7). Pore surface yellowish brown (5E7). Pores round to angular, regular, 4–5 per mm. Dissepiments entire, thick. Context up to 3.6 cm, homogeneous, golden brown (5D7). Tubes yellowish brown (5D8), up to 4 mm, not stratified.

Micromorphology – Hyphal system strictly dimitic, Generative hyphae dominant; both skeletal and generative hyphae acyanophilous; tissue darkening with KOH without swelling. Context Generative hyphae, thin to thick walled, hyaline to yellow, simple septate, branched, 2–6.2 μm diameter; skeletal hyphae, thick–walled with narrow lumen, unbranched, yellowish brown, aseptate, 2–5 μm diameter. Trama Generative hyphae, thin to thick walled, yellow to brown, septate, rarely branched, 2–5 μm diameter; skeletal hyphae, thick walled with narrow to wide lumen, yellowish brown, aseptate, unbranched, 2–5 μm diameter. Setae and cystidioles absent. Basidioles dominant, clavate to broadly clavate, 8.7–15×5–8.7 μm. Basidia clavate to broadly clavate, with four sterigmata, 9.2–16.2×5–8 μm. Basidiospores subglobose to broadly ellipsoid, thick–walled, smooth, yellow in water, turning rust brown in KOH, (5.2–) 5.5–6.2 (–6.5)×(4.4–) 4.6–4.9 (–5.2) μm (n=50/2), Q=1.2 (Q range 1.1–1.3), CB ̄, IKI ̄. Chlamydospores globose to subglobose, thick walled rust brown to reddish brown, 4.2–7.8×3.5–7.8 μm, CB ̄, IKI ̄.

Material examined – India, Tamil Nadu, Thiruvannamalai District, Sathanur, Pennaiyar river, 12º 08′ 00.34″ N 78º 56′ 48.65″ E, on living Albizzia amara (Fabaceae), 3 Febraury 2018, Sugantha Gunaseelan (MUBL4017, holotype); ibid. Kezhocuyi Kezo (PRF32/2, paratype).

GenBank numbers – ITS: MW040080, OP028975; LSU: MW048890, OP028971

Notes – Our collection shares similar microscopical features such as dimitic hyphal system and absence of cystidioles with Fulvifomes centroamericanus (Ji et al. 2017), F. combodiensis (Zhou and Zhang 2012), F. costaricense (Wu et al. 2022), F. elaeodendri (Tchoumi et al. 2020), F. hainanensis (Zhou 2014), F. imbricatus (Zhou 2015) and F. krugiodendri (Ji et al. 2017), but significantly distinct from them in macro- and micromorphological characters.

Figure 1 – Fulvifomes pannaensis (MUBL4017, halotype). a, b Basidiocarp. c Pore surface. d CS of basidiomata (d1. Context. d2. Tube layer.). e Basidia. f Basidiospores in water. g Basidiospores in cotton blue. h Basidiospores in KOH. i Basidiospores in melzer’s reagent. j Tramal hyphae. k Contextual hyphae. l Basidiospores. m Basidioles. n Basidia. Scale bars: a, b, d=1 cm, c=1 mm, e–n=5 µm