Thallus appressed throughout, moderately to loosely adnate, 1-5(-8) cm diam., saxicolous, rarely lignicolous. Lobes 1-3(-4.5) mm broad, ± flat, short and rounded, contiguous to imbricate. Upper surface yellowish-brown to red-brown or dark olive-brown, paler at apices, smooth to weakly wrinkled or pitted at apices, slightly fissured or weakly wrinkled centrally, dull throughout, or slightly shining at apices which may also be slightly pruinose, isidiate. Isidia ± spherical, pustular, 0.08-3 mm diam., often proliferating to form deep cushions. Lower surface black, often paler at apices, smooth to rather wrinkled, dull, moderately rhizinate. Rhizines concolorous with lower surface, to 0.5 mm long. Apothecia infrequent, sessile, flat to concave, to 3.5 mm diam., margins with pustular isidia. Ascospores ellipsoid, 7-9.5 × 3.5-5.5 µm. Pycnidia rare. Conidia acerose to weakly bifusiform, 4-7 × 1 µm. Chemistry: Cortex K-, HNO3+ dark, blue-green; medulla K-, C-, KC+ rose red, Pd-. Glomelliferic, glomellic and loxodic acids, often with a trace of perlatolic acid.