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

Thallus: squamulose, often lobate, forming a continuous crust over the substrate, several cm in diam., usually lacking a hypothallus lobes: ascending and digitate, appearing like soralia or isidia and acting as dispersal units squamules: thick, up to 0.4 mm wide and up to 3 mm diam., rounded, incised, densely compacted or imbricate upper surface: dark brown, margin often white due to terpenoid crystals upper cortex: paraplectenchymatous with irregularly thickened cell walls, 20-30 µm thick Apothecia: often abundent, brown, up to 1.5 mm diam., with or without and excluded thallus margin; disc: convex, brown; exciple:, subparaplectenchymatous, 60-80 µm thick; hymenium: I+ blue-green and turning red-brown, 100-120 µm high asci: clavate to subcylindrical, with apical amyloid ring structure, 8-spored ascospores: simple, colorless, ovoid, 18-22 x 9-11 µm, with a distinct epispore, often with one large oil droplet Spot tests: all negative Secondary metabolites: unidentified aliphatic acids and triterpenoids. Substrate and ecology: primarily on mosses over calcareous ground, but also occasionally on burned stumps and decomposing logs World distribution: circumpolar, arctic and alpine, following the Rocky Mountains south to Arizona and in the Sierra Nevada of California Sonoran distribution: high elevations in Arizona, California (Channel Islands). Notes: Typically it forms richly imbricate squamules over mosses and is often richly fertile.