Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Life habit: lichenized Thallus: foliose, orbicular, up to 10 cm in diam., tightly adnate to loosely appressed, lobate lobes: linear to subirregular, contiguous, plane, 2-6 mm wide, tips rounded or truncate, occasionally with lobules or laciniae upper surface: lacking a pored epicortex; bluish gray, light mineral gray, or grayish tan, becoming buff-tan or darker in the herbarium with age; occasionally with white maculae or light pruina, sometimes ridged and foveolate pseudocyphellae: sparse to common, white, orbicular to effigurate, developing into soredia or isidia in some species asexual propagules: some taxa with marginal and/or laminal soredia, lobules, or isidia medulla: white with a continuous algal layer photobiont: primary one green, Trebouxia, secondary photobiont absent lower surface: smooth to wrinkled, pale whitish-tan to black; rhizines simple, thin and often forked, generally abundant and concolorous with the lower surface Ascomata: lecanorine apothecia, laminal, sessile to substipitate disc: light to dark rusty-brown or chestnut brown; concave; margin: smooth to "chinky" with age, often pseudocyphellate (or sorediate in species with soredia), concolorous with the upper cortex asci: Lecanora-type, with an amyloid tholus, 8-spored ascospores: hyaline, simple, round to ellipsoid, 6-17 x 4-10 µm Conidiomata: absent or present, pycnidia laminal, often concentrated nearer the margins, black, sessile to weakly emergent conidia: filiform or unciform, 1 x 3-16 µm Secondary metabolites: all species contain atranorin in the cortex (in minor or trace amounts) with either lecanoric acid, gyrophoric acid accompanied by orcinyl lecanorate (=decarboxygyrophoric acid), or various fatty acids in the medulla. Geography: cosmopolitan on all continents except Antarctica Substrates: on various angiosperm and conifer barks and rocks (one species from Argentina reported from soil).