Thallus foliose, heteromerous, dorsiventral, lobate or ± squamulose or ± areolate or ± granular, orbicular to spreading, loosely or closely attached, often with a prominent black or blue-black, byssoid, marginal prothallus. Lobes variable, broad and rounded to laciniate, or microphylline and ± lobulate. Upper surface dark blue-green, plumbeous to fawnish, smooth or wrinkled-plicate, matt, glossy, or ± scabrid or pubescent, with or without isidia and soralia, maculae and pseudocyphellae absent. Medulla white. Photobiont blue-green, . Lower surface tomentose or ± rhizinate. Rhizines felted, blue-black to whitish, often projecting beyond lobe margins as a byssoid prothallus. Apothecia sessile to subpedicellate, rounded, with a persistent thalline margin, concolorous with the thallus and exterior to a thin, pale, proper margin. Ascospores 8 per ascus, ± uniseriate, simple, colourless, oblong to ellipsoid, often apiculate at one or both ends, often with a thickened or warted epispore.