Thallus whitish-grey or dirty fawn-grey, smooth, waxy, continuous or rimose, somewhat indeterminate at margins, with a thin, black marginal prothallus, in irregular patches 0.5-1.5 cm diam., saxicolous. Apothecia solitary or 1-2 confluent, 0.1-0.4 mm diam., black, matt, convex, marginate, epruinose, margins thin, concolorous with disc, prominent in young fruits, becoming occluded with age. Epithecium granular brownish-green 10-12 µm thick. Hymenium colourless 65-72 µm tall. Hypothecium pale brown. Ascospores ellipsoid-oval, fabiform, constricted at septum, ends pointed, locules equal, rounded 25 × 1 µm.