Thallus irregular, seldom orbicular, to 5 cm diam., often confluent with other thalli, ± closely attached, corticolous. Lobes overlapping or distinctly separated, to 3 mm broad, seldom ascending at apices. Uppersurface grey-brown to brown, usually with a whitish pruina, sorediate. Soralia marginal, yellowish, very seldom labriform, sometimes eroding and invading the lamina. Medulla yellowish. Lower surface brownish, sometimes black except for brown, corticate lobe tips. Rhizines numerous, black, squarrose, often forming a felty layer. Apothecia rare, usually with sorediate margins. Ascospores (25-)28-37 × 16-21 µm. Pycnidia rare, ± immersed. Conidia 4-6 × 1 µm. Chemistry: Medulla K+ yellow. Substance not identified.