Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: irregular to orbicular, to 3 cm diam. but usually larger when confluent with other thalli, loosly to firmly adnate lobes: up to 1 mm wide, usually narrower (c. 0.5 mm), mostly distinctly separate and rarely overlapping, widening at tips and weakly ascending, sparsely lobulate along margin upper surface: gray to whitish gray with a weak maculation, sorediate soredia: granular, in small, delimited, marginal soralia, sometimes sparse upper cortex: paraplectenchymatous lower cortex: paraplectenchymatous lower surface: white to pale brownish, with a few white to blackish rhizines Apothecia: not seen Pycnidia: not seen Spot tests: upper cortex and medulla K+ yellow, C-, KC-, P+ yellow Secondary metabolites: upper cortex with atranorin; medulla with atranorin and zeorin. Habitat and ecology: growing on rocks in shade in region with relatively high summer precipitation World distribution: Mexico and SE USA (North Carolina and Georgia) Sonoran distribution: Sierra Madre region of Chihuahua. Notes: Physcia pseudospeciosa is a very distinct species and easily separated by the spreading lobes and its delimited, small soralia. The species was earlier known only from the type locality but is now found on some additional localities.