Thallus ± lobate almost crustose, very closely attached, in small rosettes or spreading, to 4 cm diam., verrucose-areolate centrally, of flattened, ± radiate-plicate squamules, margins ± placoid, slightly thickened, entire or variously notched or incised, prothallus thin, black, visible between squamules, rarely projecting beyond margins. Upper surface greyish or dull brown, whitish-grey-striate, with distinctly whitish-grey margins. Apothecia ± central, sessile, often crowded, to 2 mm diam., margins conspicuous, entire or coarsely crenate, disc plane or subconvex, black, rarely dark brown, slightly granular. Ascospores ovoid-ellipsoid, smooth-walled, 12-18 × 7-10 µm, epispore ± warted-granular.