Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: small foliose, up to 4 cm wide, adnate, lobate lobes: dorsiventral, imbricate, c. 0.5-2 mm wide, often with secondary lobes, margin ± crenulate upper surface: lemon yellow to mustard yellow, smooth to somewhat wrinkled; soredia and isidia: absent upper cortex: c. 5-20 µm thick medulla: white, thin lower cortex: c. 10-35 µm thick lower surface: white to pinkish, white; rhizines: abundant, simple Apothecia: common, laminal, sessile, up 2 mm diam.; margin: smooth, often with white or yellow cilia; disc: darker yellow than the thallus; epithecium: c. 10 µm thick; hymenium: c. 60-90 µm tall; paraphyses: simple or branched near the tips, cylindrical to submoniliform with up to 5 µm wide tips; hypothecium: 30-45 µm thick asci: clavate, >30-spored ascospores: uni- or biguttulate, colorless, 7-11 x 4-6 µm Pycnidia: common, immersed, concolorous with upper surface or slightly darker conidia: ellipsoid, to narrowly ellipsoid 2-3.5 x 1.5 µm Spot tests: upper surface K- (or + deeper yellow), C-, KC-, P-; medulla K-, C-, KC-, P- Secondary metabolites: calycin (major) and pulvinic dilactone (minor). Habitat and ecology: on bark, often in very humid microclimates, such as martime regions World distribution: pantropical and extending into some warm temperate regions Sonoran distribution: in oak forests up to at least 2000 m in southern Arizona, Chihuahua and Sinaloa. Notes: This species is characterized by the lack of soredia or isidia.