Thallus 10-20 mm diam., continuous, smooth or very slightly farinose (at margins of leaves somewhat sorediate), greenish-grey, sometimes with a white, marginal prothallus, foliicolous. A thin, white mycelium without algae extends on the lower surface of the leaves from parts where the epiphyllous, algiferous thallus reaches the leaf margin. Apothecia constricted at base, 0.2-0.4 mm diam., rare on the algiferous, epiphyllous thallus but abundant on the hypophyllous mycelium (often on the very margin of the leaves), there often aggregate, disc of epiphyllous apothecium testaceous brown, of the hypophyllous apothecia chocolate brown, epruinose, plane or subconvex, margins thin, but conspicuous, white, matt, often minutely downy. Ascospores 3-septate, sometimes 5-septate, oblong to subfusiform, ends usually obtuse, often slightly constricted at septa, 12-18 × 3-4 µm.