Thallus small, foliose-squamulose, very closely attached, orbicular to spreading, 2-5 cm diam., with a thin, blue-black prothallus projecting from margins, corticolous or saxicolous. Squamules small, radiating, orbicular, to 3 mm diam., margins subcrenate, whitish or dark bluish. Upper surface pale greyish to yellow-brown, smooth, matt, without isidia, pruina or soredia, minute, flattened, crenate, cochleate, lobules developed marginally and centrally in older thalli, often forming a diffract-areolate crust. Apothecia sessile, prominent, 0.5-1.5 mm diam., disc red-brown, plane, with a thick, pale brown, persistent proper margin. Ascospores ellipsoid, 14-18(-20) × 7-10 µm.