Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: foliose, adnate to loosely adnate, 3-20 cm in diam., lobate lobes: subirregular, elongate, often imbricate, plane, separate, 4-15 mm wide; apices: rotund, sometimes deeply crenate, sometimes ascending, elacinate, ciliate; cilia: frequent, up to 2.0 mm long upper surface: gray, sometimes with some blackened areas, smooth, dull to shiny, emaculate to faintly white maculate soredia: granular, common, in linear, marginal to submarginal soralia that often erode large areas and causing the margin to become revoute; isidia and pustulae: absent medulla: white, with continuous algal layer lower surface: black with brown naked zone peripherally, centrally rhizinate; rhizines: scattered, simple, black Apothecia: very rare, substipitate, up to 7 mm in diam.; margin: sparsely sorediate; disc: brown, imperforate ascospores: ellipsoid to broadly ellipsoid, 22-30 x 13-18 µm Pycnidia: not seen Spot tests: upper cortex K+ yellow, C-, KC-, P-; medulla K+ yellow turning orange, C-, KC-, P+ orange Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with stictic acid (major) and constictic acid (minor), norstictic, menegazziaic and cryptostictic acids (trace). Substrate and ecology: usually on hardwood trees in open habitats, occasionally on rocks World distribution: widespread in temperate region of the Northern and Southern Hemispheres Sonoran distribution: common on oaks and other trees and shrubs in coastal woodlands of California and Baja California, much rarer inland in Arizona and Sonora.