Thallus in small, confluent patches 1-3 cm diam., greyish-white or blue-grey or greenish-grey on a thick, black prothallus, very thin, minutely and regularly areolate-cracked, areolae angular, ± flat, bounded by a narrow, black, marginal prothallus. Apothecia ± solitary to 1-4 confluent, immersed to adnate, sunk in plane of thallus, not raised above thallus surface, rounded or cracked-deformed, disc black, matt, epruinose, 0.5-1.0 mm diam., margins very narrow, entire, black, persistent. Epithecium green-black, 8-13 µm thick. Hymenium colourless, 40-60 µm tall. Hypothecium thick, brown-black. Ascospores oblong with rounded apices, 8-12 × 3-5.1 µm.