Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: shrubby, caespitose, up to 3 cm long branching: simple or sparingly branched, growing from a narrow holdfast branches: solid, flattened, dissected near the apices, 0.3-2(-5) mm wide surface: greenish yellow, somewhat shiny, sorediate soredia: coarsely granular with subcorticated granules, in marginal or laminal, ellipsoid soralia that soon become confluent forming continuous decorticated areas at the lower surface of distal branches or along the margins of branches pseudocyphellae: sparse or almost lacking, ellipsoid, flat cortex: thin, 7-8 µm thick; chondroid strands: smooth, continuous on upper side, discontinuous on the lower side Apothecia: not seen Pycnidia: not observed Spot tests: cortex K-, C-, KC+ yellow, P-; medulla: K-, C-, KC-, P- Secondary metabolites: cortex with usnic acid; medulla with divaricatic acid (major) and 4'-O-demethyldivaricatic acid (minor). Substrate and ecology: on acidic rocks World distribution: endemic to northwestern Mexico Sonoran distribution: known from higher elevations between 2000 to 3000 m in mountain regions of Chihuahua. Notes: Ramalina chihuahuana resembles R. pollinaria that differs in having uneven surfaces of branches and producing evernic and obtusatic acids.