Thallus crustose, whitish to greyish, continuous, smooth, thin, effuse, usually poorly developed and sometimes evanescent, occasionally delimited by a dark brown hypothallus line. Soralia and isidia absent. Photobiont Trentepohlia. Anamorph: conidiomata pycnidia, 60-100 μm diam., occasional, mostly arranged in lines or groups, black, half-immersed to sessile. Conidia 3.5-4.6 × ca 0.8 μm, bacilliform. Teleomorph: ascomata apothecia, 0.4-1.5 (-2) mm diam., disciform, black, sessile, slightly constricted at the base. Disc sometimes thinly grey-green-pruinose, especially in young apothecia. Thalline exciple absent. True exciple persistent, prominent, ± crenulate. Hymenium 60-120 µm tall, I+ reddish, K/I+ blue. Subhymenium 25-40 µm thick, brownish in the inner part and hyaline in the upper part, I+ and K/1+ blue. Interascal tissue composed of pseudoparaphyses, 1.5-2 µm diam., the apical cell thickened (to 4-5 µm), with a distinct dark brown cap which is formed in the inner part of the cell wall. Asci 60-75 (-80) x 12-13 µm, cylindrical to cylindric-clavate, short-stalked, thick-walled and fissitunicate, 8-spored. Ascospores arranged bieriately, 18-25 × 4.5-6 (-7) μm, cylindric-fusiform, with pointed ends, often curved, (4- to) 5- (to 7-) septate, often appearing slightly distoseptate, hyaline, thick-walled, smooth, without an epispore, gelatinous sheath or appendages. Chemistry: no lichen products detected by TLC.