[Imbricaria borreri var. stictica (Delise ex Duby) Flot., moreParmelia borreri var. stictica Delise ex Duby, Parmelia dubia var. stictica (Delise ex Duby) Schaer., Parmelia stictica (Delise ex Duby) Nyl., Parmotrema sticticum (Delise ex Duby) M. Choisy]
Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: closely adnate, foliose, lobate lobes: sublinear, contiguous, plane, narrow, 1-2 mm wide, apices truncate upper surface: brownish gray to brown, especially towards the tips, smooth, never pruinose, but also at least partly marginal pseudocyphellae: numerous, conspicuous, white, round to usually elongate to somewhat branched, laminal, reaching 0.5 mm soredia: granular, irregular, grayish white, often with bluish gray discoloration, originating from pseudocyphellae, marginal and laminal, up to 0.4 mm in diam., but joining into larger, linear or irregularly shaped structures lower surface: usually black centrally, brown marginally; rhizines: concolorous with the lower cortex Apothecia: absent in Sonoran material Pycnidia: absent Spot tests: upper cortex K+ yellow, C-; medulla K-, C+ rose Secondary metabolites: upper cortex with atranorin (minor or trace); medulla with gyrophoric acid (major) and orcinyl lecanorate (=decarboxygyrophoric acid) (minor). Substrate and ecology: on rocks from 460 m on San Clemente Island, California) to 2880 m (Hidalgo) World distribution: possibly cosmopolitan, known from North, Central and South America, Europe and Africa Sonoran distribution: Arizona and California (Channel Islands) .