Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.

Life habit: lichenised Thallus: foliose, dorsiventral, heteromerous, large (5-25 cm diam.), spreading, loosely attached lobes: subirregular, 0.5-2.5 cm broad, rounded; without marginal cilia upper surface: ashy white to gray or tan, with small, punctiform pseudocyphellae, isidiate or sorediate upper cortex: prosoplectenchymatous [paraplectenchymatous according to Elix (1993)], with a nonpored epicortex, 10-30 micro meter thick medulla: white, loose; cell walls: containing isolichenan, I-; photobiont: primary one a Trebouxia, secondary photobiont absent lower surface: black, shiny, corticate, sometimes punctate, rhizinate; rhizines: simple Ascomata: apothecial, laminal, occasionally marginal, 0.5-4 mm diam., round, stipitate, submarginal, usually perforate; thalline exciple: persistent; hymenium: colorless; paraphyses: unbranched or little branched; hypothecium: hyaline asci: cylindrical, Parmelia-type, unitunicate, thick-walled, I+ blue, tholus I+ blue, 8-spored ascospores: ellipsoid, simple, hyaline, 11-22 (-25) x 6-12 micro meter Pycnidia: marginal, immersed conidia: simple, colorless, 5 x 1 micro meter Secondary metabolites: upper cortex with atranorin and chloroatranorin, medulla with a range of orcinol depsides and depsidones Geography: temperate to tropical; one species boreal-arctic Substrate: on bark or wood, less frequently rocks. Notes: It is characterized by punctiform pseudocyphellae on upper surface, perforate apothecia with large, ellipsoid spores, and bifusiform conidia. It is closely related to Platismatia; distinguished from that genus (at least from P. glauca) by having distinct pseudocyphellae, ± continuously rounded margins, the I- medulla and distinctive medullary chemistry. It may also be mistaken for Parmotrema species, but they lack pseudocyphellae.