Thallus creamish-white, 0.7 mm thick, continuous, smooth or very finely and minutely areolate-cracked, in round or irregular patches, delimited at margins by a thin black line of prothallus. Apothecia scattered, sessile, constricted at base, solitary, rounded, 0.2-0.5(-0.8) mm diam., disc black or blue-black, grey-pruinose at first, then epruinose, margins at first raised, entire, black, excluded at maturity. Epithecium granular, greenish-black or greenish-grey, 8-13 µm thick. Hymenium colourless or pale straw-coloured, to 90 µm tall. Hypothecium colourless, opaque, Ascospores oblong-ellipsoid, 8.3-12.0 × 5-6.8 µm.