Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: foliose, medium sized, +circular, up to 8 cm in diam., lobate lobes: plane, subirregular, spreading, 2-3(-6) mm wide upper surface: bluish gray to light mineral gray; shiny, wrinkled and ridged, maculate, margin ±pruinose pseudocyphellae: white, rare, marginal and laminal, punctiform or rarely irregular in shape isidia: dense, cylindrical or rarely slightly flattened, short to elongate, smooth and corticate, simple to forked or coralloid; apices: ±pruinose or brown-tipped; often arising from lobe margin or on laminal ridges, not breaking up into soredia-like masses, occasionally becoming extremely dense and "mounded" obscuring the thallus lobes lower surface: pale, white to ivory or pale brown; rhizines: simple to forked, concolorous with the lower surface or darkening to brown or brown-black Apothecia: not seen Pycnidia: common, immersed to slightly emergent Conidia: unciform, 4-6 x 1 µm Spot tests: upper cortex K+ yellow, C-, medulla K-, C-, KC-, P- Secondary metabolites: upper cortex with atranorin (minor), chloroatranorin (minor), medulla containing protoconstipatic acid (major), constipatic acid (minor), dehydroconstipatic acid (minor), dehydroprotoconstipatic acid (minor). Substrate and ecology: on bark of conifers World and Sonoran distribution: thus far known only known from the type collection in Baja California. Notes: Punctelia cedrosensis closely resembles P. rudecta in morphology but differs in having sparse pseudocyphellae (dense in P. rudecta) and in containing the constipatic acid chemosyndrome of fatty acids in the medulla (lecanoric acid occurs in P. rudecta).