Thallus: primary thallus crustose, areolate, the areoles scattered to contiguous, to 1 mm diam., grey, spreading, with slightly tumid margins and a darker central area, remaining conspicuous especially when wet. Soralia, when present, usually confined to the margins of the areoles. Pseudopodetia and cephalodia absent, but cyanobacteria are often abundant between the areoles. Anamorph: no information available. Teleomorph: ascomata apothecia, rather frequent, developing from between the thalline areoles; disc to 1.5 mm diam., black, the exciple distinct. Hypothecium dark brown. Ascospores (25-) 30-38 (-40) × 6-7 μm, 3- to 5-septate, ± sub-clavate with one end ± tapered, rarely fusiform. Chemistry: thallus K+ yellow, KC+ violet, Pd+ faintly yellow, UV+ white (atranorin and lobaric acid).