Thallus closely attached, pale greenish or green-grey, 3-7(-10) cm diam., in rosettes or ± spreading. Lobes sublinear, ± convex, often crowded and ± imbricate, margins entire, sinuses semicircular, smooth or slightly wrinkled or subpapillate, rarely submaculate towards margins, isidiate. Isidia ± densely developed centrally, occasionally also marginal, to 1 mm tall, simple to ± coralloid, terete, bulbous, swollen at apices and bursting open, pustular, not forming soredia. Lower surface black, shinning, wrinkled, rhizines moderately developed, richly dichotomously branching. Apothecia rare, subpedicellate, 0.2-2.0 mm diam., deeply cupulate at maturity, exciple entire, concolorous with thallus, becoming crenulate with age, not isidiate, disc pale yellow-brown to red-brown, matt, imperforate. Chemistry: Cortex K+ yellow; medulla K-, C-, KC+ rose, Pd-. Atranorin, colensoinic, norcolensoinic, 4-O-demethylphysodic, physodic and lividic acids.