Thallus: foliose, loosely adnate, 3-30 cm in diam., lobate lobes: subirregular, elongate, slightly imbricate, plane, separate, 10-20 mm wide; apices: rotund, becoming crenate and dissected with age, ciliate; cilia: up to 2.0 mm long upper surface: gray, smooth, dull centrally, shiny marginally, emaculate, finely reticulately cracked with age isidia: simple to coralloid branched, frequently very dense, sometimes apically ciliate, common, laminal to marginal; soredia and pustulae: absent medulla: white with continuous algal layer lower surface: black with brown naked zone peripherally, centrally rhizinate; rhizines: simple Apothecia: rare, substipitate, up to 8 mm in diam.; margin: sparsely isidiate; disc: brown, usually imperforate ascospores: ellipsoid to broadly ellipsoid, 13-16 x 7-10 µm Pycnidia: rare, punctiform conidia: filiform, 12-16 x 1 µm Spot tests: upper cortex K+ yellow, C-, KC-, P-; medulla K-, C+ red, KC+ red, P- Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with lecanoric acid (major), orsellinic acid (trace). Substrate and ecology: usually on trees in open habitats, rarely on rocks World distribution: pantropical and adjacent temperate regions Sonoran distribution: coastal plain to mountains of southern Baja California Sur and Sinaloa.