Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Thallus: determinate, cracked-areolate, 0.4-0.6 mm thick, with broad fissures, without a black basal layer, with a thick and abrupt margin, without a visible prothallus areoles: subangular in outline, plane, 0.5-1.5 mm wide, secondarily subdivided into smaller units which may overlap each other in 2-3 horizons, slightly constricted at base, with pale flanks surface: brown, dull, uneven to verrucose anatomy: with a poorly defined upper cortex but paraplectanchymatous throughout, overlain with a thin epinecralic layer, uppermost cell layer pale brown; with algal cells 6-10 µm in diam. distributed throughout most of thallus or concentrated in upper half, mycobiont cells 4-7 µm in diam. Perithecia: several per areole, arising in lower parts of the areoles, finally with apices appearing at the surface, but hardly protruding; exciple: subglobose or ellipsoid, 0.15-0.25 mm wide, colorless to brown, apically black, 15-20 µm thick; involucrellum: lacking; periphyses c. 20 µm long, simple asci: clavate, 8-spored ascospores: hyaline, simple, ellipsoid, 17-20 x 8-10 µm Pycnidia: unknown Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: epilithic, on sandstone World distribution: Europe, Algeria, and North America Sonoran distribution: known only from two samples from northern Arizona (Coconino Co.). Notes: The circumscription of the species follows Vainio (1921). So named herbarium material differs considerably and seems to represent several other species.