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

Thallus: adnate to loosely adnate, foliose, 6-15 cm in diam., often fusing to cover large areas, irregularly lobate lobes: sublinear to irregular, elongate, plane to subconvex, separate, 3-8 mm wide; apices: subrotund, crenate, eciliate upper surface: yellow-green, smooth but becoming rugose with age, dull to somewhat shiny, epruinose and emaculate pustulae: abundant, laminal crateriform, isidioid, breaking open apically but not sorediate; true isidia and soredia absent medulla: white with continuous algal layer lower surface: black centrally and toward margin, narrow brown zone peripherally, smooth to papillate; rhizines: sparse to moderately abundant, black, simple Apothecia: rare, laminal on thallus, sessile, 1-4 mm wide; disc: brown; margin: pustulate, pruina and soredia absent asci: clavate, 8-spored ascospores: simple, ellipsoid, hyaline, 13-15 x 6-7 µm Spot tests: upper cortex K-, C-, KC+ yellow, P-; medulla K-, C+ red, KC+ red, P+ red Secondary metabolites: upper cortex with usnic acid; medulla with protocetraric acid (major) and gyrophoric acid (minor to accessory). Substrate and ecology: commonly on acidic rock, rarely tree bases World distribution: eastern and SW North America Sonoran distribution: central Arizona south along the Sierra Madre Occidental, Southern California and Baja California.