Thallus ± orbicular, loosely attached, to 6 cm diam. Lobes whitish-grey to leaden grey when dry, blue-grey when wet, 0.3-0.8(-1) cm wide, often imbricate, broadly cuneate to flabellate, very often with transverse, concentric ridges, apices rounded, margins entire, occasionally minutely notched, ± conspicuously deflexed. Upper surface smooth, somewhat coriaceous, matt, without isidia, rarely with regenerating lobules. Lower surface pale, with numerous rhizines in transverse concentric lines. Rhizines usually white, sometimes bluish-black (then often with white tips) usually not projecting beyond lobe margins. Apothecia frequent, to 1.5 mm diam., disc concave at first becoming plane or convex with age, usually pale reddish-brown often blackened, proper margin pale, sometimes blackened, in old apothecia often occluded, rarely with white projecting hairs at base. Ascospores 11-16 × 5-7 µm.