Thallus loosely attached, ± orbicular to irregular, 2-8 cm diam., corticolous. Lobes rounded, 3-10 mm wide, undulate, ± imbricate centrally, margins free, thickened, crisped, ± ascending, entire or with eroding, linear soralia on lower surface. Upper surface dark grey-blue or blackish, minutely white-maculate (×10 lens) or with irregular white or brownish, algal-free patches, greyish brown when dry, matt, shining, rather coriaceous. Soredia bluish-grey, coarse, granular, in linear soralia often eroding back from margins of lower surface. Medulla white. Photobiont blue-green. Lower surface pale brown at margins, dark brown or black towards centre, ± uniformly thick-tomentose to margins. Cyphellae conspicuous but rather few, scattered, round to irregular, sunk in tomentum, 0.1-2.0 mm diam., white, with a conspicuous, pale, raised rim. Apothecia not seen.