Porogramme principes Melo, Salcedo, C.A. Garcia & Olariaga, 2023

Melo, Ireneia, Salcedo, Isabel, Garcia, Cesar A. & Olariaga, Ibai, 2023, Two new species of resupinate poroid fungi (Basidiomycota, Polyporaceae) from São Tomé and Príncipe Archipelago, Phytotaxa 607 (1), pp. 41-56 : 50-51

Porogramme principes Melo, Salcedo, C.A. Garcia & Olariaga , sp. nov. ( Figs. 5 , 6 )

MycoBank No: MB 849191

Type:— SÃO TOMÉ AND PRÍNCIPE. Príncipe Island: at the foot of Pico Mesa , 319 m, 1°35ʹ10.72ʺ N 7° 21ʹ26.47ʺ E, 22 November 2016, on unidentified wood, C.A. Garcia & J. R. Shevock, LISU 254185 ! (holotype) .

Description:—Basidiome annual, resupinate, strongly adnate, hard, up to 300 µm thick; pore surface whitish to light cream (10YR 8/2–8/3), unchanged when dry, pores angular to irregular, 3–4 per mm, pore edges sterile and finely floccose due to the dendrohyphidia; tubes shallow, up to 150 µm deep, hyphal pegs absent; context and trama pale cinnamon in section, dense in the structure; hymenium whitish and restricted to the base of the tubes; margin farinaceous. Hyphal system dimitic with clamped generative hyphae; generative hyphae 1.5–3 µm diam., hyaline, thin-walled in subhymenium, thin to thick-walled in trama and context; basal hyphae made of generative hyphae, thick-walled, 3–3.5 µm diam., strongly agglutinated; skeletal hyphae 2–3 µm diam., light cream, thick-walled, weakly dextrinoid, present in context and trama. Bipyramidal crystals present in context. Dendrohyphidia present and easy to observe in the edge of dissepiments, hyaline, finely branched at the top, arising at the end of generative hyphae; hymenial hyphidia up to 30 µm long, thin-walled, branched at the apex. Basidia 15–20 × 4.5–5 µm, subclavate, with a slight median constriction, with 4 sterigmata up to 5 µm long. Basidiospores 4.5–6 × 3–3.2(–3.5) µm, oblong-ellipsoid, thin-walled, smooth, hyaline, non-amyloid.

Etymology:— principes , refers to Príncipe, an island from the S„o Tomé and Príncipe Archipelago.

Notes:—Our phylogenetic analyses ( Fig. 1 ) show that P. principes nests in the clade recognized by Mao et al. (2023) as Porogramme (Pat.) Pat. The latter authors separated also Cyanoporus, characterized by inhabiting monocotyledon hosts, and kept Grammothele featured by having dendrohyphidia. From a morphological point of view, besides the presence of dendrohyphidia the placement of P. principes in Porogramme is furthermore justified by its whitish to light cream pore surface, pores 3–5 per mm, absence of hyphal pegs, and oblong-ellipsoid basidiospores, 4.5–6 × 3–3.2(–3.5) µm. The species identified as Grammothele taiwanensis C.C. Chen in Jayawardena et al. (2023: 195), sister to P. principes in our analyses ( Fig. 1 ), differs in having considerably larger spores (7.9–10.5 × 3.3–4.4 µm), 8–9 substitutions in the ITS region and possibly a different distribution. Porogramme principes differs from P. subargentea due to the latter having a basidiome with whitish to violet pores and cylindrical basidiospores, 5.2–8.3 × 2.6–3.1 µm. Porogramme cylindrica also has hyphal system dimitic, basidiome whitish to cream, but the skeletal hyphae are not dextrinoid and its basidiospores are larger than in P. principes , 8–10 x 3.1–8.3 µm and 5–6 × 2.5–3 µm, respectively (Mao et al. 2003).

Figures

FIGURE 1. Best tree of the Maximum Likelihood analysis of Grammothele s.l. from ITS sequence data. Maximum Likelihood ultrafast bootstrap values (ML-BP) / Bayesian Posterior probabilities (PP) are shown on branches, ordered as ML-BP/PP. Thickened branches received support at least in one analysis (ML-BP ≥95 % and/or PP ≥0.95). Asterisks indicate full support in both analyses. Names recognized are indicated on the right side.

FIGURE 5. Porogramme principes (holotype LISU 254185). Pore surface of the basidiome.

FIGURE 6. Porogramme principes (holotype LISU 254185). a) pores; b) section through basidiome; c) generative and skeletal hyphae; d) dendrohyphidia from the edge of dissepiments; e) basal hyphae; f) basidia and hymenial hyphidia; g) basidiospores; h) crystals. Drawing by I. Melo.