Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life habit: lichenized Thallus: peltate, crustose, squamulose, or suffruticose (rarely cylindrical); margins: entire, minutely lobate to sometimes effigurate upper surface: olive green to olive brown, rarely black; with or without soredia upper cortex: usually absent but with an epinecral layer medulla: white, with numerous airspaces, composed of globose or elongated hyphae photobionts: primary one an unicellular cyanobacterium (Chroococcidiopsis or Myxosarcina), secondary photobiont absent lower cortex: normally well developed, pseudoparenchymatous lower surface: usually paler than the upper surface, attached by an umbilicus, rhizohyphal weft or rhizines Ascomata: apothecial, lecanorine, completely immersed or with a raised rim; disc: punctiform or widely opened; hymenium: 90-300 µm high; paraphyses: sometimes anastomosing, rarely branched, 1-3.5 µm thick; subhymenium: 16-70 µm asci: clavate to obclavate, unitunicate-rostrate (lecanoralean type), 60-170 x 10-30 µm; walls: red or blue in iodine (blue after K pretreatment); 16->100-spored ascospores: simple, hyaline, globose to ellipsoid, 3-12 x 2-6 µm Conidiomata: pycnidial, solitary to cerebriform, immersed conidia: oval to fusiform, hyaline, 1.5-4.3 x 0.5-2.5 µm Secondary metabolites: none detected in North American material Geography: predominately in arid and semi-arid regions of the world, but occurring wherever arid microclimates are found Substrate: acidic or calcareous rocks or soil.