Thallus to 20 cm diam, often forming conspicuous, extensive patches., ± closely appressed but becoming somewhat detached towards the centre. Lobes 5-13 mm wide, wavy, rounded at the apices, ± contiguous at the tips but overlapping at the centre, the margins often indented. Upper surface yellow to yellow-green, occasionally grey-green (in shade), often coarsely corrugate especially towards the centre, pustulate-sorediate. Soredia coarse and granular, occasionally adhering and forming gnarled lumps. Lower surface black, brown towards apices, rhizines absent from a narrow zone along the margin. Ascomata rare, to 8 mm diam, disc red-brown, the thalline exciple ± sorediate. Ascospores 15-19(-22) x (8-)9-10 µm, ellipsoidal. Pycnidia not known.