Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: foliose, 3-7 cm in diam., rather fragile, loosely adnate, subdichotomously lobate lobes: sublinear to subirregular, elongate, plane to subconvex, 1-3 mm wide; margin: entire; apices: subtruncate to subrotund, subconvex upper surface: gray to greenish gray, smooth, shiny; emaculate isidia: laminal, cylindrical, mostly simple; soralia, pustulae, and dactyls all absent medulla: white with continuous algal layer lower surface: black, tips brown, becoming subcanaliculate; rhizines: dense, black, dichotomous Apothecia: sparse, laminal, substipitate, 2-3 mm in diam.; disc: brown; margin crenulate, isidiate asci: clavate, 8-spored ascospores: ellipsoid, 12-14 x 6-8 µm Pycnidia: not seen Spot tests: upper cortex K+ yellow, C-, KC-, P+ yellow, UV-; medulla K-, C+ red, KC+ red, P- Secondary metabolites: upper cortex with atranorin and chloroatranorin; medulla with gyrophoric and 5-O-methylhiascic acids (both major). Substrate and ecology: on bark and rocks in open montane forests World distribution: primarily tropical in North and South America and Africa Sonoran distribution: Sierra Madre Occidental of Chihuahua.