Thallus dorsiventral, heteromerous, foliose-lobate, closely attached, corticolous. Lobes narrow 1-4 mm wide, sublinear to subirregular, margins generally ciliate. Upper surface with a paraplectenchymatous cortex and a pored epicortex. Lobules, isidia, maculae and soredia often present. Photobiont green, . Medulla white or pale yellow. Lower surface black, rarely pale, rhizinate. Rhizines black, rarely pale, simple to sparsely furcate or squarrose. Apothecia sessile, 5 mm or less in diam., disc imperforate, thalline exciple smooth, occasionally rhizinate. Ascospores simple, colourless, 8 per ascus, uniform within a given species and not notably different between unrelated species.