Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life habit: lichenized Thallus: foliose, c. circular in outline, lobate lobes: usually subirregular, apices: usually rotund, cilia absent upper surface: yellow green to yellow (rarely green to blue green), smooth, plane to rugulose, shiny or dull, often with soredia or pustules, emaculate, usually epruinose, pseudocyphellae absent upper cortex: pored epicortex, palisade plectenchymatous medulla: white, sometimes lower part pigmented; cell walls: containing isolichenan photobionts: primary one a Trebouxia, secondary photobiont absent lower surface: black, frequently with a brown margin, plane to sometimes wrinked, attachment by simple rhizines, cyphellae, pseudocyphellae and tomentum absent Ascomata: apothecial, imperforate, laminal on thallus, orbicular, cup-shaped, sessile, margin prominent with thalloid rim; exciple: gray or hyaline; epithecium: brown or brownish yellow; hypothecium: hyaline asci: lecanoral, with thickened wall layers towards the apex; apex: amyloid, with wide, axial body divergent towards apex; 8-spored ascospores: simple, ellipsoid; 14-20 x 7-10 µm; wall thin, hyaline Conidiomata: absent or present, pycnidial, laminal, immersed conidia: bacilliform, bifusiform or fusiform, 6-10 x 1 µm Secondary metabolites: upper cortex with usnic acid, rarely also atranorin and chloroatranorin; medulla with some combination of orcinol depsides, ß-orcinol depsides, ß-orcinol depsidones, (higher) aliphatic acids, antraquinones or other quinones, secalonic acids or amino acid derivatives Geography: cosmopolitan outside of polar and moist tropical regions Substrate: mostly bark or non-calciferous rock. Notes: This is a segregated from Pseudoparmelia, sensu Hale (1976c) and is characterized by having broad lobes, black lower surface, larger ascospores, short pycnospores, a yellow-green upper surface (usnic acid).