Thallus foliose, dorsiventral, heteromerous, lobate, corticolous or saxicolous. Lobes sublinear, narrow, apically truncate. Upper surface with or without isidia, with or without soredia, with or without maculae, pseudocyphellae absent, whitish-grey to yellowish. Medulla white. Photobiont green, . Lower surface uniformly black, rhizinate. Rhizines black, dichotomously branched, conspicuous and often projecting beyond margins. Apothecia lecanorine, uniformly small, 1-5 mm diam., sessile, disc imperforate. Ascospores simple, colourless, 4-10 × 8-16 µm, 8 per ascus.