Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: fruticose, shrubby to subpendulous, up to 10 cm long branching: moderately branched, growing from a narrow holdfast branches: solid, flat to weakly canaliculate, 4-7(-15) mm wide surface: ocher yellow or yellowish green, surface rugose towards the tips, longitudinal ridges of chondroid strands or striations common, without soredia pseudocyphellae: various from subrotund, elliptical or short linear, slightly depressed, abundant on lower side of branches cortex: distinct, 15-20 µm thick; chondroid strands: continuous or discontinuous especially in aged branches, smooth to weakly cracked Apothecia: common, laminal, or subterminal, entire or radially split disc: concave, without white margins; margin: concolorous with the thallus, reticulately ridged, often pseudocyphellate asci: elongate-clavate, 8-spored ascospores: hyaline, 1septate, broadly fusiform, 11-14 x 3.5-4 µm Pycnidia: common, laminal, with pale ostioles, mixed with tubercles conidia: rod-shaped, 3-4 x 0.5 µm Spot tests: cortex K-, C-, KC+ yellow, P-; medulla K-, C-, KC-, P- Secondary metabolites: cortex with usnic acid (major); medulla with divaricatic acid (major) and salazinic acid (±trace). Substrate and ecology: on twigs World distribution: endemic to Mexico Sonoran distribution: Baja California, Baja California Sur, Sonora and Sinaloa. Notes: Ramalina sonorensis might be confused with R. bajacalifornica, that differs in having narrowly fusiform ascospores and by producing only salazinic acid. It resembles R. complanata, a species widely distributed in Central and South America, from which it can be distinguished by having elliptic or short linear pseudocyphellae.