Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: tightly adnate to adnate, foliose, 4-8 cm in diam., lobate lobes: narrow, sublinear to subirregular, contiguous to imbricate, somewhat elongate, convex, separate, 0.6-3 mm wide, lobe tips subrotund upper surface: pale greenish to yellowish gray, smooth but cracked with age, dull, becoming rimose, emaculate, becoming strongly rugulose soredia: coarse, in linear to irregular pustulae, coarse, becoming diffuse, submarginal, isidia absent medulla: white lower surface: purplish black centrally, gray marginally, sparsely rhizinate, rhizines black, simple Apothecia: not seen Pycnidia: not seen Spot tests: cortex K- or K+ yellow (depending on atranorin concentration), C-, KC+ yellow, P+ yellow; medulla K-, C-, KC-, P- Secondary metabolites: upper cortex with atranorin, chloroatranorin and usnic acid, medulla with alectoronic acid (major). Substrate and ecology: open boulder fields in arctic, upper montane to alpine areas World distribution: arctic North America southwards at scattered localities throughout the Rocky Mountains and in the Great Lakes area Sonoran distribution: only known from one location on rocks in an upper montane scree slope in the Chiricahua Mountains of SE Arizona.