Thallus spreading, closely attached 4-8(-20) cm diam., corticolous or saxicolous. Lobes rounded, crenate or regularly incised, dissected, somewhat crowded, margins sinuous, black, shining, isidiate. Upper surface smooth, shining, glossy, wrinkled, becoming ± faveolate at or near margins, wrinkled- ridged centrally, pale greenish-white or greenish-greyor pale bluish-grey, often brownish at margins, pseudocyphellae small, punctiform, mainly marginal, not becoming sorediate. Isidia flattened, lobate-squamiform, rarely terete and simple, becoming strongly dorsiventral, marginal in young lobes, spreading densely over surface of older lobes. Lower surface uniform pale buff or tan with a smooth, pale, naked marginal zone. Rhizines central, simple, pale, long, often densely developed. Apothecia occasional, pedicellate, to 10 mm diam., disc dark red-brown, matt, smooth, imperforate, plane to deeply concave, thalline exciple concolorous with thallus, pseudocyphellate and isidiate. Spores subglobose to broadly ellipsoid, 15-20 × 10-12 µm. Chemistry: Cortex K+ yellow; medulla K-, C+ red, KC+ red, Pd-. Lecanoric acid and atranorin.