Thallus thin and papery, orbicular to spreading, often in very large rosettes to 20(-40) cm diam., ± loosely attached, corticolous, very rarely saxicolous. Lobes broadly rounded (5-25 mm wide) or slightly elongate-imbricate, margins rounded, entire, with a fine, black or brown shining rim, occasionally developing crowded lobules centrally. Upper surface smooth, rarely faveolate-cracked centrally, shining, undulate, greyish-green, not darker at margins, often with a bluish tinge, pseudocyphellae small, white, sigmoid, scattered evenly over upper surface, often minute and crowded at lobe margins but not forming a reticulum of white lines. Lower surface black, smooth with a narrow, brown, naked marginal zone, rhizinate centrally. Rhizines black, sparse to numerous, simple to squarrosely branched. Apothecia common, pedicellate, to 15 mm diam., disc plane or subconcave, matt, reddish-brown to yellowish-brown, greenish-blue in shaded specimens, often centrally perforate, margins entire, thalline exciple smooth, shining, concolorous with Thallus, maculate or pseudocyphellate. Ascospores ellipsoid, 14-16 × 8-12 µm. Chemistry: Cortex K+ yellow; medulla K+ yellow → red, C-, KC+ red, Pd+ orange. Salazinic acid and atranorin.