Thallus irregularly spreading, (2-)5-15 cm diam., loosely attached, corticolous. Lobes ± linear-elongate, subcanaliculate to plane, subdichotomously to irregularly or complexly branched, 1-10 mm wide and 0.5-5 cm long, margins entire, slightly thickened, occasionally ± ascending, rarely subdenticulate with raised, yellow pseudocyphellae. Upper surface shallowly to deeply faveolate, interconnecting ridges smoothly rounded or sharp, dark grey-blue when wet and conspicuously white-maculate in well-defined patterns (×10 lens), pale greyish or greenish-grey to greyish-buff when dry, sometimes suffused reddish- brown in parts, matt or slightly shining, often irregularly cracked, minutely scabrid-areolate in parts. Medulla white. Photobiont blue-green. Lower surface pale whitish-buff, distinctly wrinkled-bullate, ± evenly tomentose to margins, tomentum thin, silky, short, white or buff, thicker and darker (becoming brown) centrally. Pseudocyphellae minute, bright yellow, round, 0.05-0.3 mm diam., scattered, slightly raised above tomentum, decorticate area plane, margins not prominent. Apothecia marginal or submarginal, subpedicellate, 0.5-3.5 mm diam., plane to shallowly convex-undulate, disc in young stages obscured by margins, at maturity dark red-brown to black, matt, epruinose, margins denticulate, pale buff or flesh-coloured, often obscured by disc, exciple corrugate-scabrid, buff or pale flesh-coloured. Ascospores biseriate, brown, mainly polaribilocular, occasionally 3-septate, 20-30.6 × 8.3-10.2 µm. Pycnidia occasional to frequent, scattered, black, punctiform, minute. Chemistry: Calycin, pulvinic dilactone, pulvinic acid, tenuiorin, methyl lecanorate, gyrophoric acid (tr.), hopane-6α,22- diol, salazinic and consalazinic acids and an unidentified terpene.