Thallus loosely attached, 1-10 cm diam., corticolous. Lobes ± dichotomously branched, sublinear-elongate, 1-4 mm wide. Upper surface pearly grey or whitish, shining, margins phyllidiate. Phyllidia numerous, ascending, short rhizinate below, often branched to 1.5 mm long, spreading over whole upper surface. Maculae and soredia absent. Lower surface black, smooth, densely rhizinate. Rhizines black, shining, dichotomously branched. Apothecia not seen. Chemistry: Cortex K+ yellow; medulla K-, C-, KC+ pink, Pd-. Atranorin, alectoronic and (-collatolic acids (UV+ blue-white).