Thallus forming orbicular patches to 8 cm diam., but generally smaller, saxicolous. Lobes at margins and centre contiguous, inflated, densely crowded, highly wrinkled and puckered, subirregularly divided, 0.8-3 mm wide, secondary lobes ± subdichotomously branched and more loosely packed, subimbricate to highly imbricate, primary lobes not divergent at axils but generally exhibiting parallel growth, at least when young, marginal lobes placodioid, apices moderately flattened to ± inflated and adnate. Upper surface brown-black, or in part pale brownish-grey to grey with black variegations, smooth and moderately shining near margins, esorediate, but with lobulate or lobulate-isidoid projections occurring centrally on upper surface. Medulla white, becoming discoloured with age, hollow. Lower surface black, dull and roughened, pale brown at apices. Apothecia numerous to sparse, occasionally absent, to 7 mm diam., sessile or subpedicellate, with a pitted, wrinkled, funnel-shaped exciple, disc dark brown to bay, concave at first, becoming ± plane, margin entire and persistent, at first ± markedly involute. Asco-spores ellipsoid, 5-8 × 4-6 µm. Chemistry: Cortex K+ yellow; medulla KC+ red, Pd+ red. Atranorin, chloroatranorin, 3-hydroxyphysodic, physodic, alectoronic, ± 2' -O-methylphysodic, ± physodalic and ± protocetraric acids.