Thallus foliose, dorsiventral, heteromerous, lobate, greenish-yellow, brownish-red or greyish-brown, or ± greyish in sheltered situations, usually quite thin, 100-300 µm thick, spreading, 2-30 cm diam., corticolous or saxicolous. Upper surface corticate, smooth, wrinkled or faveolate-impressed, matt or shining, sometimes ± maculate, isidia or phyllidia present or absent, soredia and pseudocyphellae absent. Photobiont green () or blue-green () in a layer 30-60 µm thick, green photobiont species often have internal cephalodia of blue-green algae present towards the lower surface. Medulla white, of loosely woven hyphae, 40-260 µm thick. Lower surface corticate, black or pale brown or whitish, bullate, or smooth and ± undulate. Apothecia non-emergent, on lower surface at apices of lobes, discs red-brown or light to dark brown. Ascospores 8 per ascus, 1- to 3-septate, pale brown.