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 or tufted, up to 7(-15) cm long branching: irregularly or dichotomously branched from a narrow holdfast branches: solid, irregular in thickness or plane, 1-3(-5) mm wide surface: greenish gray to greenish yellow, smooth, shiny, sorediate soredia: farinose, in laminal or marginal, rounded, discrete soralia pseudocyphellae: almost lacking in distal branches, more common near the base of branches, ellipsoid to short linear cortex: thin; chondroid strands: continuous, weakly to heavily cracked Apothecia: rare but frequent in local populations in some limited areas, mostly laminal, up to 6 mm in diam. disc: covered with thin pruina; margin: concolorous with the thallus, entire, usually lacking pseudocyphellae asci: elongate-clavate, 8-spored ascospores: hyaline, 1-septate, broadly fusiform, 12-15 x 5-7 µm Pycnidia: not observed Spot tests: cortex K-, C-, KC+ yellow, P-; medulla K+ yellow or yellow turning dark red, C-, KC-, P+ yellowish orange Secondary metabolites: cortex with usnic acid; medulla with (race 1) protocetraric acid (major); (race 2) norstictic (major) acid and salazinic acid (±trace). Substrate and ecology: on bark, rarely on rock World distribution: cosmopolitan, especially common in temperate, coastal regions Sonoran distribution: southern California, Baja California and Baja California Sur. Notes: Among the two chemical races of Ramalina farinacea, race 1 (protocetraric acid) is more common in the greater Sonoran region. The distribution of the chemical races in North America have been extensively investigated by Bowler (1977).