Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.

Thallus: foliose, loosely adnate, 3-15 cm in diam., lobate lobes: subirregular, elongate, slightly imbricate, plane, separate, 10-20 mm wide, margin becoming lacerate to lacinate with age; apices: rotund, ciliate; cilia: up to 4 mm wide upper surface: gray with some blackened areas, smooth to rugulose, shiny, epruinose, strongly white maculate, becoming reticulately cracked with age; soredia, isidia and pustulae: absent medulla: white with continuous algal layer lower surface: black with brown with a mottled ivory (rarely tan) naked zone peripherally, centrally rhizinate; rhizines: scattered, simple Apothecia: common, substipitate, up to 20 mm in diam.; margin: rugose, white maculate; disc: brown, perforate ascospores: broadly ellipsoid, 12-16 x 7-9 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 norstictic acid (major) and connorstictic acid (minor). Substrate and ecology: usually on trees in open habitats, rarely on rocks World distribution: Mexico, eastern USA, southern Africa and Ireland Sonoran distribution: Sierra Madre Occidental region of Chihuahua.