Thallus: foliose, loosely adnate to adnate, 3-10 cm in diam., lobate lobes: subirregular, elongate, slightly imbricate, plane, separate, 5-12 mm wide; margin: becoming dentate or lacinate with age; lacinae: 5-10 x 1-2 mm; apices: rotund, ciliate; cilia: sparse, simple, up to 2.0 mm long upper surface: gray to green-gray, smooth, dull, strongly reticulate maculate, becoming reticulately cracked with age along the maculae, isidiate isidia: laminal and marginal, cylindrical, simple to branched, tips often bearing cilia, more common marginally; soredia and pustulae absent medulla: white with continuous algal layer lower surface: black with brown zone peripherally, rhizinate to margin; rhizines: scattered, mostly simple, sometimes bifurcate to squarrose Apothecia: rare, up to 5 mm wide; margin: thalline, isidiate; disc: brown, imperforate or perforate ascospores: simple, hyaline, ellipsoid, 12-14 x 6-10 µm Pycnidia: common, immersed conidia: filiform, 10-12 x 1 µm Spot tests: upper cortex K+ yellow, C-, KC-, P+ yellow; medulla K+ yellow turning deep red, C-, KC-, P+ orange Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with salazinic acid (major) and consalazinic acids (minor). Substrate and ecology: usually on trees World distribution: Arizona to Central America, east Africa Sonoran distribution: Sierra Madre Occidental of Chihuahua and Sonoran and southern Baja California Sur.