Thallus appressed or pulvinate, loosely adnate, 3-6 cm diam., saxicolous. Lobes 1.5-3 mm broad, flat to slightly convex, short and rounded, rather closely imbricate and entangled. Upper surface dark olive-brown to brown-black or grey-black, paler at apices, smooth at apices, strongly wrinkled centrally, dull, subnitid at apices, without isidia. Lower surface brown-black to black, pale at apices, smooth, dull, moderately rhizinate. Rhizines simple, concolorous with lower surface, to 0.7 mm long. Apothecia sessile, concave, to 1 mm diam., margins entire. Ascospores broadly ovoid to ellipsoid, 8-11.5 × 5-5.7 µm. Pycnidia common. Conidia weakly bifusiform, 1.1-7 × 1 µm. Chemistry: Cortex K-, HNO3 ± dark blue-green; medulla K-, C-, KC+ rose, Pd-. 4-O-methylolivetoric acid.