Polymeridium – Facesoffungi number: FoF 08805

Polymeridium (Müll. Arg.) R.C. Harris in Tucker & Harris, Bryologist 83: 12 (1980).

MycoBank number: MB 4316; Index Fungorum number: IF 4316; Facesoffungi number: FoF 08805; Approximately 50 morphologically defined species (Aptroot and Lücking 2016; Aptroot and Weerakoon 2018); molecular data available for three species (Lücking et al. 2016).

Lichenized on bark in terrestrial, chiefly lowland to lower montane tropical habitats, often in drier situations. Thallus usually ecorticate, rarely indistinctly corticate, whitish. Photobiont Trentepohlia. Ascomata solitary to aggregate, erumpent to prominent, black, hemisphaerical to wartshaped or conical, carbonaceous, ostiolate, ostiole apical, rarely lateral or fused. Involucrellum carbonized. Excipulum prosoplectenchymatous, brownish to carbonized. Hamathecium comprising 0.5–0.7 µm wide paraphysoids, hyaline, straight, branched and anastomosing, embedded in a gelatinous matrix. Asci 4–8-spored, bitunicate, fissitunicate, clavate, short pedicellate, with a non-amyloid ocular chamber. Ascospores irregularly arranged to biseriate, fusiform ellipsoid, hyaline, multi-septate to rarely (sub-)muriform, with thin eusepta and rectangular lumina, smooth-walled, not or slightly constricted at the septa, often with a gelati- nous sheath. Pycnidia rare, immersed to erumpent, visible as black dots. Conidia aseptate, bacillar, hyaline.

Chemistry: lichexanthone sometimes produced on thallus surface; ostiolar area or hamathecium rarely with anthraquinones.

Type species: Polymeridium contendens (Nyl.) R.C. Harris in Tucker & Harris, Bryologist 83: 12 (1980).

Notes: For key and discussion see Aptroot and Lücking (2016).

Species