Tropicoporus cleistanthicola S. Gunaseelan & M. Kaliyaperumal, 2024

Gunaseelan, Sugantha, Kezo, Kezhocuyi, Karunarathna, Samantha C., Yang, Erfu, Zhao, Changlin, Elgorban, Abdallah M., Tibpromma, Saowaluck & Kaliyaperumal, Malarvizhi, 2024, New species of Tropicoporus (Basidiomycota, Hymenochaetales, Hymenochaetaceae) from India, with a key to Afro-Asian Tropicoporus species, MycoKeys 102, pp. 29-54 : 29

Tropicoporus cleistanthicola S. Gunaseelan & M. Kaliyaperumal sp. nov.

Figs 3 , 4

Etymology.

The specific epithet cleistanthicola (Lat.) refers to the host Cleistanthus collinus .

Diagnosis.

Tropicoporus cleistanthicola is characterised by perennial, effused-reflexed to pileate, applanate to triquetrous basidiome with narrowly zonate, glabrous, meagrely warted pilear surface, acute margin, homogenous context, mono-dimitic hyphal system, presence of cystidioles and subglobose to broadly ellipsoid basidiospores measuring 4.7-5.4 × 4.2-4.9 μm.

Type.

India, Tamil Nadu, Thiruvannamalai District, Jawadhu Hills , 12°54'24"N, 78°87'75"E; 15 Nov 2019; Sugantha Gunaseelan; on a living angiosperm tree ( Cleistanthus collinus ); SMK-PMP11 (MUBL1089; Holotype); GenBank: OR272292 (ITS); OR272337 (nLSU) .

Description.

Basidiome perennial, pileate, solitary, hard corky and without distinctive odour or taste when fresh, woody hard and light in weight when dry. Pilei effused-reflexed to pileate, dimidiate, triquetrous in section, projecting up to 4 cm, 6.5 cm wide and 3 cm thick at the base; Pileal surface narrowly zonate, glabrous, meagrely warted near attachment, yellowish-brown (5E6; 5E8) to dark brown (6F5), turning dark brown (7F4) to greyish-brown (6F3). Margin acute, 1 mm thick, light brown (6D5). Pore surface brown (6E6) to dark brown (6F7); sterile margin up to 2 mm wide, light brown (6D5); pores circular, 5-7 per mm. Context homogenous, up to 1.5 cm thick, brown (6E8). Tubes up to 0.5 cm long, tube layers distinctly stratified, each stratum up to 2 mm, brown (6E7).

Hyphal structures.

Hyphal system monomitic in the context and dimitic in the trama, tissue darkening with KOH without hyphal swelling.

Context.

Generative hyphae, thin to thick-walled, hyaline to golden yellow, simple septate, rarely branched, 2-5 μm diam.

Trama.

Generative hyphae, dominant, thin to thick-walled, hyaline to pale yellow, septate, occasionally branched, 2-4 μm diam. Skeletal hyphae thick-walled with narrow to wide lumen, yellowish-brown, aseptate, unbranched, 2-3.5 μm diam.

Hymenium.

Hymenial setae dark brown, thick-walled, ventricose to subulate with sharp to blunt tips, 5-32 × 4-5.5 μm. Cystidia absent. Cystidioles hyaline, thin-walled, ventricose to fusoid with elongated tapering apical portion, 7-45 × 2-5 μm. Basidia clavate to broadly clavate, 7-15 × 2.7-6.2 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 5-13 × 3.5-6 μm. Basidiospores broadly ellipsoid to subglobose, pale yellow in water, turning golden yellow to brown in KOH, thick-walled, smooth, CB ̄, IKI ̄, (4.7-) 4.9-5.2 (-5.4) × (4.2-) 4.5-4.7 (-4.9) μm (n = 50/2), Q = 1.1 (Q range 1.05-1.2).

Habitat and distribution.

Basidiomes were found on living trees of Cleistanthus collinus ( Phyllanthaceae ), distributed in Jawadhu Hills, Thiruvannamalai District, Tamil Nadu, India.

Additional material examined.

India, Tamil Nadu, Thiruvannamalai District, Jawadhu Hills ; 12°51'20"N, 78°73'71"E; 15 Nov 2019; Sugantha Gunaseelan; on a living angiosperm tree ( Cleistanthus collinus ); SMK-PMP14 (MUBL1090, Paratype); GenBank: OR272291 (ITS); OR272336 (nLSU) .

Notes.

The present phylogenetic study indicated that T. cleistanthicola is sister to T. rudis with significant support (92% ML/0.9 BPP). However, T. rudis has applanate basidiomes with fulvous, velvety, concentrically zonate, matted, rimose pilear surface, whereas T. cleistanthicola has triquetrous basidiome and glabrous pilear surface with infrequent warts without cracks. Tropicoporus cleistanthicola and T. rudis are comparable only in mono-dimitic hyphal system and T. rudis lacks cystidioles and has larger basidiospores (4.9-6 × 4-4.8 μm) ( Wu et al. 2022). Despite sharing pileate basidiomes, mono-dimitic hyphal system and presence of cystidioles in T. linteus , T. cleistanthicola differs by having effused-reflexed to pileate, narrowly zonate, meagrely warted pilear surface ( Tian et al. 2013; Wu et al. 2022). Tropicoporus cleistanthicola resembles T. angustisulcatus , T. dependens , T. excentrodendri , T. substratificans and T. lineatus by sharing pileate, triquetrous basidiomes with concentrically zonation and presence of cystidioles, but T. cleistanthicola differs by having a mono-dimitic hyphal system and spore size (4.7-5.4 × 4.2-4.9 μm) ( Zhou et al. 2015; Wu et al. 2022). Tropicoporus cleistanthicola and T. drechsleri are similar in having pileate basidiomes and a mono-dimitic hyphal system with the presence of cystidioles, but T. cleistanthicola differs by having smaller pores (5-7 pores/mm) and larger basidiospores ( Salvador-Montoya et al. 2018). Except for sharing a mono-dimitic hyphal system and indistinctly stratified tube layers, T. cleistanthicola differs from T. flabellatus and T. guanacastensis in pores (size and shape), basidiospore shape and absence of cystidioles ( Zhou et al. 2015; Lima et al. 2022).

Figures

Figure 3. Tropicoporus cleistanthicola (MUBL 1089 holotype) A basidiomata (Holotype) B pore surface C cross-section of basidiome (arrows indicating stratified tube layers) D hymenial setae E-H basidiospores: E basidiospores in water F basidiospores in KOH G basidiospore in cotton blue H basidiospore in Melzer's reagent. Scale bars: 1 cm (A-C); 5 µm (D-H).

Figure 4. Tropicoporus cleistanthicola (MUBL 1089 holotype) A contextual hyphae B tramal hyphae C hymenial setae D cystidioles E basidioles F basidia G basidiospores. Scale bars: 5 µm.