Thallus white or grey-white irregularly rimose to areolate-cracked, areolae angular, convex or ± plane, 0.3-1.0 mm diam., separated by deep cracks, surface matt, roughened, areolae becoming ± confluent and forming a subverrucose crust, in patches 0.5-1.5 cm diam., prothallus marginal, indistinct, saxicolous. Apothecia innate to sessile, scattered, between or at margins of areolae, solitary to 1-3-confluent, rounded to deformed through mutual pressure, 0.3 mm diam., disc plane, black, epruinose, margin very thin, entire, persistent, concolorous with disc. Hypothecium brown-black. Ascospores biseriate, brown, ellipsoid or oval to ± fabiform, apices rounded, 11-13 × 5-6 µm.