Thallus corticolous, rarely muscicolous over rocks, of one to several primary branches, at first broadly flattened, then dividing palmately intoseveral smaller, usually fertile branches. Primary branches horizontal, to 3 cm long and 4-11 mm wide, commonly with small, irregular, marginal secondary branches. Upper surface green-grey, smooth to wrinkled, becoming ± scrobiculate towards apices especially over apothecia, lower surface white, irregularly wrinkled, particularly round base of apothecia, upper cortex 65-100 µm thick, lower cortex 40-70 µm thick. Algal layer 20-40 µm thick, continuous beneath upper cortex only. Apothecia common, 2-9 mm diam., subterminal, with broadly flaring margins, mazaedium ventral, exposed at an early stage of development, receptacle corticate, with small isidia-like structures along margins. Asci 45-55 × 5-11 µm. Ascospores spherical, grey-brown, 9-12(-13.5) µm, walls with external deposit of black, carbonaceous material. Chemistry: K+ reddish or -, Pd-. Three unidentified compounds. Sphaerophorin absent.