Thallus 2-5 (-15) cm diam., closely appressed, rosette-forming; lobes to 10 mm wide, subirregular, rounded at the apices, ± overlapping and becoming crowded at the centre, not down-turned; margins crenate with cilia mainly restricted to axils; upper surface blue-grey or grey, mostly smooth and often shiny, faintly to distinctly maculate, the maculae at times developing into cracks; lower surface dark brown to black, paler brown towards the lobe ends, rhizines simple. Isidia and soredia absent. Anamorph: conidiomata pycnidia, common, laminal. Conidia 4.5-6.5 × 0.5-1 μm, bacilliform, straight. Teleomorph: ascomata apothecia, frequent, to 7 mm diam., sessile. Disc initially imperforate but becoming perforate, red-brown. Thalline exciple intact or small-incised, ± densely black rhizinate at or towards the point of attachment. Ascospores (8-) 9-11 × 6-8.5 μm, almost spherical to broadly ellipsoidal, aseptate, hyaline, thin- and smooth-walled, without an epispore, gelatinous sheath or appendages. Chemistry: cortex K+ yellow. Medulla C+ carmine-red, K–, KC+ red, Pd–, UV– (atranorin, lecanoric acid).