Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: crustose, leprose, irregular, indeterminate, firmly fastened to the substrate, forming a thin layer of soredia; lobes not evident upper surface: gray-green, blue-green or gray-blue, dull soredia: mostly farinose, up to 70(-110) µm in diam., fluffy, sometimes with shortly projecting hyphae medulla: absent lower surface: not evident, without tomentum Spot tests: thallus K- , C-, KC- , P-; UV+ bluish white Secondary metabolites: atranorin, zeorin, divaricatic and nordivaricatic (trace accessory) acids. Substrate and ecology: on bark, including Quercus agrifolia and Lithocarpus densiflorus World distribution: Africa, Asia, Europe, North America, South America and New Zealand Sonoran distribution: southern California from near sea level to 400 m.