Tropicoporus flabellatus V.R.T. Oliveira, J.R.C. Oliveira-Filho, Xavier de Lima & Gibertoni, 2022

X, Vitor, Lima, avier de, T, Virton Rodrigo, Oliveira, argino de, C, Nelson, Lima-Júnior, orreia de, C., José Ribamar, Oliveira-Filho, Santos, Carla, Lima, Nelson & Gibertoni, Tatiana Baptista, 2022, Taxonomy and phylogenetic analysis reveal one new genus and three new species in Inonotus s. l. (Hymenochaetaceae) from Brazil, Cryptogamie, Mycologie 20 (1), pp. 1-21 : 10-12

Tropicoporus flabellatus V.R.T. Oliveira, J.R.C. Oliveira-Filho, Xavier de Lima & Gibertoni , sp. nov.

This species is characterized by the thin flabelliform basidioma, presence of hymenial setae, pores 7-9/mm and basidiospores 4.5-5 Μm long.

MYCOBANK NUMBER. — MB 837432.

HOLOTYPE. — Brazil, Alagoas State, Quebrangulo City , REBIO de Pedra Talhada, on dead wood, 9°15’00.7”S, 36°25’38.3”W, 758m, 25.VII.2019 V. R. T. Oliveira, ( URM [ URM94338 ]).

ADDITIONAL SPECIMENS EXAMINED. — Brazil, Pernambuco State, Recife, Recife’s Botanical Garden, on dead wood, 17. VI.2016, J. R. C. Oliveira-Filho, as Inonotus cf. pseudoradiatus ( URM [ JB 7])

ETYMOLOGY. — “ Flabellum ” (Latin) meaning “small fan”. Referring to shape of the basidioma.

HABITAT AND DISTRIBUTION. — Tropical, ombrophilous broadleaf forest.

DESCRIPTION

Basidioma ( Fig. 6A ) perennial, pileate, sessile, dimidiate, solitary to imbricate, applanate to slightly convex in section ( Fig. 6B ), 2.9-3.5 cm wide, 2.1-2.8 cm long, 0.5-0.9 cm thick at the base, hard, twisting when dry. Pileus surface radially folded, often with projections; initially velutinate, but soon wearing in narrow black and brown concentric zones. Margin acute. Pore surface ( Fig. 6C ) dark brown to brownish-yellow near the margin, pores round, 7-9/mm; margin sterile, brownish-yellow. Context 0.3-0.5 cm thick at the base, golden-brown, duplex, with a thin black line near the pilear surface.Tubes golden-brown, slightly darker than the context, indistinctly stratified (up to three layers in the holotype), old tubes filled with concolorous mycelia. Context and tubes turning immediately purplish-black in contact with KOH 3%, drying out remaining as a dark spot. Hyphal system in the context monomitic, generative hyphae simple and mostly regularly septate, sparingly branched, hyaline, yellow, golden yellow in water and rusty brown in KOH, mostly thick-walled with wide to narrow lumen, rarely hyaline and thin-walled, 3-5.5 Μm in diameter, wall up to 1.5 Μm thick; black line is composed by dark reddish-brown, more densely agglutinated and intertwined hyphae ( Fig. 6H ); below the line, hyphae grow parallel to the pilear surface, near the tube they grow downwards to form the tube trama, and above the line, hyphae concolorous or slightly darker, growing upwards to compose the tomentum. Tomentum hyphae straight, thick-walled with a wide lumen, yellow to dark yellow in water, rusty brown in KOH 3%, 3-5.5 Μm diameter, richly septate, ends obtuse or clavate, mostly broken ( Fig. 6I ). Tube trama dimitic, hyphae growing straight, perpendicular to the pilear surface, generative hyphae hyaline to yellow, thin to slightly thick-walled, 2.5-4 Μm in diameter, skeletal hyphae ( Fig. 6G ) golden yellow in water, brownish-yellow in 3% KOH, thick-walled with a narrow lumen, wall up to 2 Μm thinning out towards the apex, unbranched, 3.5-4.5 Μm in diameter. Hymenial setae ( Fig. 6D ) rare in the holotype, 10-20 × 6-8.5 Μm brownish yellow in water, dark rusty-brown in KOH 3%, originating in the trama, near pore mouths, projecting inside the tube or immersed in the trama. Cystidiole not observed. Basidia tetrasterigmate, subglobose, 7-9 × 5-6 Μm. Basidiospores ( Fig. 6E ) ellipsoid with a flattened side, 4.5-5 × 3.5-4 Μm (Q = 1.12-1.42), thick-walled, smooth, pale yellow in water and golden yellow in 3% KOH, CB-, IKI-.

REMARKS

The thin and small basidiomata, and the small pores characterize this species. Although perennial, the formation of a dark crust was not observed in older parts of the pileus surface. The other known neotropical pileate Tropicoporus with small pores is T. guanacastensis (7-8/mm, Zhou et al. 2016). However, T. guanacastensis produce harder and thicker basidiomata, and a crust in the upper surface that cracks with age. Although pileate, T. flabellatus V.R.T. Oliveira, J.R.C. Oliveira-Filho, Xavier de Lima & Gibertoni , sp. nov. is placed within the T. tropicalis clade, which is composed by resupinate species, making it readily distinguishable from this species

Figures

FIG. 6. — Tropicoporus flabellatus V.R.T. Oliveira, J.R.C. Oliveira-Filho, Xavier de Lima & Gibertoni, sp. nov. (URM94338): A, dried basidiomata; B, longitudinal section, red arrow pointing to the black line in the context; C, pore surface; D, hymenial setae; E, basidiospores; F, generative hypha with basidia at the end; G, skeletal hypha of the tube trama; H, hyphae of the black line in the context; I, hyphae of the tomentum. All preparations in 3% KOH. Scale bars: A, B, 1cm; C, 5 mm; D-I, 10 μm