Thallus heteromerous, crustose to dwarf-fruticose, mainly grey but also white, yellow, green or blue-black, surface smooth, tuberculate, wrinkled-plicate and continuous, cracked or areolate. Cortex paraplecten-chymatous, becoming abraded or disorientated. Medulla white, variable in thickness, of loosely woven, thin-walled hyphae. Photobiont green, . Apothecia innate, within verrucae, generally elevated above thallus surface, single or several in pseudostromata; disc small and punctiform to broad and lecanorine. Parathecium weakly developed, never carbonised. Paraphysoids septate, branching from near base, variouslyspaced, becoming reticulately branched. Epithecium prominent, hyaline to dark, sometimes K+ violet. Hypothecium reduced, hyaline never K+ violet. Hymenium subglobose to discoid, hymenial gelatine colourless, yellow-brown or red. Asci clavate or cylindrical, 1-8-spored. Ascospores oval, ellipsoid, fusiform or cylindrical, simple, multinucleate, large, walls single or double, usually hyaline, mainly thick. Pycnidia immersed, globose or racemose, ostiolate or erumpent. Conidia cylindrical, filiform to acicular.