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, slightly imbricate, plane, separate, 10-20 mm wide; apices: rotund, often ascending and wavy, ciliate; cilia: up to 5 mm long upper surface: gray with some blackened areas, smooth, dull to shiny, faintly white maculate soredia: granular, common, in linear, marginal to submarginal soralia; isidia and pustulae: absent medulla: white with continuous algal layer lower surface: black with brown to mottled white naked zone peripherally, centrally rhizinate; rhizines: scattered, simple Apothecia: rare, substipitate, up to 10 mm in diam.; margin: crenulate; disc: brown, often perforate ascospores: ellipsoid to broadly ellipsoid, 15-22 x 9.5-12 µm Pycnidia: laminal, immersed conidia: 10.5-11.5 µm long Spot tests: upper cortex K+ yellow, C-, KC-, P-; medulla K-, C-, KC+ red or orange, P- Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with alectoronic acid (major) and α-collatolic acid (minor). Substrate and ecology: on hardwood trees (often among mosses) in relatively exposed positions World distribution: neotropics and extending well into temperate regions to the north and south, Macaronesia, throughout Europe and New Zealand Sonoran distribution: common on live oaks in woodlands of southern California, especially the Channel Islands.