Thallus minutely squamulose-microphylline, very closely attached, spreading, to 8 cm diam., with a conspicuous, black, marginal prothallus, corticolous. Squamules variable in size and shape, effigurate, or forming a diffract-areolate crust, or denuded altogether. Upper surface dirty greyish-brown, matt, without isidia or soredia. Apothecia frequent, 0.8-1.5 mm diam., disc plane, dark red-brown to blackened, with a thin proper margin, often occluded, concolorous with disc or paler. Ascospores ellipsoid, often apiculate at both ends, 16-21 × 7-10 µm.