Thallus usually thick, rarely thin, greyish white to pale brownish grey, continuous, farinose or cracked-areolate. Anamorph: conidiomata pycnidia, not seen in GB material. Conidia are 5-7 x ca 1 µm, and curved. Teleomorph: apothecia rare, 0.2-1.1 mm diam., roundish to angular, or elliptical to elongate (then to 2 mm long), sometimes substellate, black, at first immersed then sessile. Disc flat to strongly domed, usually strongly white or bluish white pruinose. True exciple thin to thick, dark brown, often prominent, or becoming excluded. Exciple and hypothecium K– (not greenish). Epithecium hyaline to dark brown (K+ greenish). Hymenium 50-70 (-85) μm tall, hyaline, I+ red, with branching and anastomosing paraphyses with swollen and pigmented tips. Asci 50-75 × 11-13 μm, cylindric-clavate, thick-walled and fissitunicate, 8-spored. Ascospores 12-17 (-19) × 3-4 (-5) μm, cylindric-ellipsoidal to cylindric-fusiform, initially 3-septate, constricted at the septa and sometimes with one to three non-constricted secondary transverse septa, hyaline, smooth, thick-walled, surrounded by a thin gelatinous sheath. Chemistry: thallus and apothecial pruina C+ red, K–, Pd–, UV– (lecanoric and gyrophoric acids and erythrin).