Marcelaria Aptroot, M.P. Nelsen & Parnmen, Glalia 5(2): 3 (2013), nom. cons. prop.
MycoBank number: MB 805450; Index Fungorum number: IF 805450; Facesoffungi number: FoF 08803; three morphologically defined species (Aptroot and Lücking 2016); molecular data available for two species (Lücking et al. 2016).
= Buscalionia Sambo nom. cons. prop., Ann. Bot., Roma 22: 27 (1940).
Type species: Buscalionia rubra Sambo, Ann. Bot., Roma 22: 27 (1940) [= Marcelaria purpurina (Nyl.) Aptroot, Nelsen & Parnmen].
Lichenized on bark in terrestrial, chiefly lowland tropical wet forest habitats. Thallus distinctly corticate, yellow-brown to olive-green. Photobiont Trentepohlia. Ascomata solitary to often crowded or loosely aggregate, prominent to sessile, brown-black but covered by thick thallus and a thick layer of yellow-orange to red pigment crystals, hemispherical to wart-shaped, coriaceous, ostiolate, ostiole apical. Excipulum prosoplectenchymatous, dark brown to carbonized. Hamathecium comprising 0.5–0.7 µm wide para-physoids, hyaline, straight, branched and anastomosing, embedded in a gelatinous matrix. Asci 2–8-spored, bitunicate, fissitunicate, oblong-clavate, short pedicellate, with a non-amyloid ocular chamber. Ascospores irregularly arranged to biseriate, fusiform-ellipsoid, hyaline, richly muriform, with somewhat thickened distosepta and rounded lumina, smooth-walled, not or slightly constricted at the septa, often with a gelatinous sheath. Pycnidia unknown.
Chemistry: lichexanthone sometimes produced on thallus surface; yellow to orange or red anthraquinones present on the ascomata.
Type species: Marcelaria purpurina (Nyl.) Aptroot, Nelsen & Parnmen, Glalia 5(2): 9 (2013) [= Buscalionia rubra Sambo, Ann. Bot., Roma 22: 27 (1940)].
Notes: For key and discussion see Aptroot and Lücking (2016). The older name Buscalionia has recently been discovered to be congeneric with Marcelaria and has been proposed for conservation (Aptroot and Nepi 2017), with the decision pending.