Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: foliose, tightly adnate to rocks, up to 5 cm in diam.; lobate lobes: narrow, subirregular, contiguous, becoming imbricate, 1-3 mm wide upper surface: light mineral gray with shiny, distinct, dark gray-brown margin pseudocyphellae: white, abundant, round to elongate, up to 0.5 mm isidia: low, "papilliform," dull, simple to sparingly branched, breaking apart, often arising from cracks or the margins of pseudocyphellae; brown tipped, eroding into dull, "lumpy granules" on the surface of older portions of the thallus lower surface: pale tan to deep flesh-colored, darker at the margin; rhizines: simple, thin, unbranched, generally concolorous with the lower surface Apothecia: not seen Pycnidia: not seen in Sonoran material but reported (Adler 1997) as unciform and filiform, (4-)5-7(-8) µm Spot tests: upper cortex K+ yellow, C-, KC-, medulla K-, C+ red, KC+ red Secondary metabolites: upper cortex with atranorin (minor or trace), medulla producing lecanoric acid (major). Substrate and ecology: tightly adnate on rocks in coastal areas World Distribution: South Africa, South America (Adler 1997), and coastal California and Mexico. Sonoran distribution: coastal California (Ventura County) and Baja California Sur. Notes: The first North American records were reported from rocks near the California coast (Riefner 1989) based on material verified by Mason Hale, Jr., who first described the species from South Africa. The specimen from Baja California Sur is also strikingly similar to isotype material housed at the United States National Herbarium (US). Adler (1997) proposed an expanded view of this South African taxon which included the corticolous Punctelia missouriensis G. Wilh. & Ladd, but Aptroot (2003) prefers to treat that taxon as a distinct, corticate-"sorediate" species.