Description: Thallus crustose to subsquamulose, episubstratic, sulphur yellow to rarely pale ochraceous brown, areolate, sorediate, developing on a blackish hypothallus. Areoles 0.2-0.8 mm across, easily detached from the substrate, scattered or in small groups, at first flat, then strongly convex, largely occupied by a crater-like soralium; soredia greenish yellow, 20-80 μm thick. Apothecia very rare, lecanorine, with a concave to flat, yellowish brown disc, and a thick, usually sorediose thalline margin. Asci and ascospores not known. Photobiont chlorococcoid. Spot tests: K+ yellow to reddish brown (at least in the prothallus), C-, KC-, P-. Chemistry: pulvinic acid derivatives.
Note: on underhanging surfaces of hard, mineral-rich siliceous rocks (gneiss, schists), mostly in fissures, occasionally on epilithic mosses, with optimum in upland areas.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)