Thallus in stripes or patches, 1-2(-5) cm diam. Upper surface chalky-white, roughened, chinky, areolate-cracked, smooth in parts, matt, not minutely granular or furfuraceous. Apothecia innate, very small, 0.1-0.3 mm diam., clustered, very irregular in shape, often immersed in declivities in substrate, disc not easily seen, contorted through mutual pressure, concave to plane, dark brown or black, delicately white-pruinose, margins thick, white, concolorous with thallus, irregular, sinuous, contorted, ± inflexed, obscuring disc, often split and fissured. Ascospores fusiform, 7-11-septate, slightly curved, 55-80(-86) × 5-7 µm. Chemistry: Cortex K+ yellow. Stictic, hypostictic acids and unidentified compound A.