Thallus crustose, whitish or grey, usually hypophloeodal, sometimes epiphloeodal, usually corticolous. Photobiont green, -like. Ascomata perithecioid, immersed to erumpent, subglobose, usually dimidiate, peridium dark brown or black. Paraphyses trabeculate pseudoparaphyses, branched and anastomosing, scarcely septate, centrum not reacting with I. Asci arising from base of ascomatal locule, cylindrical or elongate-clavate, bitunicate, with an internal apical beak, non-amyloid, fissitunicate, usually 8-spored. Ascospores uniseriate to biseriate or irregular, ellipsoid, apices rounded or slightly attenuate, 1(-3)-septate, the single or first-formed septum towards the lower end of the spore in most species, almost central in others, usually somewhat constricted at septum, colourless, smooth-walled, lacking a conspicuous gelatinous sheath. Pycnidia commonly present, black, immersed. Conidia subglobose to narrowly ellipsoid, sometimes dimorphic, simple, colourless. Chemistry: usually -.