Thallus foliose, lobate, ± orbicular to spreading, closely attached, to 10 cm diam., without a marginal, projecting prothallus, corticolous or saxicolous. Lobes narrow, 1-2 mm wide, flabellate-cuneate, contiguous or imbricate, margins rounded, ± shallowly incised or crenate, conspicuously thickened below, whitish, scabrid (×10 lens). Upper surface pale greyish to yellow-grey, minutely granular or leprose (×10 lens) towards margins, smooth or subrugose or ridged, often strongly wrinkled-plicate centrally, isidiate. Isidia simple, granular at first, becoming gnarled-glomerulate, whitish-blue, marginal and on interlobe ridges, or occasionally scattered on upper surface, or becoming dense and forming a diffract-areolate crust centrally. Lower surface pale buff or creamish, tomentose at margins with tufts of short, brownish squarrose rhizines towards centre. Apothecia sessile, 1-1.5 mm diam., plane or subconvex, disc yellowish to pale red-brown, epruinose, margins thin, wrinkled, becoming isidiate-lobulate. Ascospores ellipsoid-oval, contents granular, 10-19 × 6-10 µm, wall 1-1.5 µm thick.