Thallus orbicular, rosette-forming to 10 cm diam., closely attached, corticolous. Lobes radiating, to 3 mm broad, discrete to ± imbricate. Upper surface whitish-grey to dark grey, densely white-maculate and sometimes also weakly white pruinose. Lower surface white to pale brown with pale brown to brown rhizines. Apothecia common, often numerous,rounded to ± contorted by mutual pressure, to 3 mm diam., disc often white-pruinose. Ascospores 16-26(-29) × 7-11 µm. Pycnidia immersed. Conidia 4-6 × 1 µm. Chemistry: Cortex and medulla K+ yellow. Atranorin and zeorin.