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

Thallus: peltate, scattered, individual thalli up to 22 mm in diam., often lobate; margin: undulate upper surface: gray, pruinose, spot-like soredia: farinose, black, marginal, rarely occurring upper cortex: with numerous air spaces, 4.5-13 µm thick and with an epinecral layer (7-18 µm thick) medulla: composed of loosely interwoven hyphae with elongated cells (2-3.6 µm thick); algal layer: clearly delimited above, 55-100 µm thick lower cortex: paraplectenchymatous, 24-37 µm thick, composed of 3 (rarely 4) rows of hexagonal cells (4.5-7.5 µm in diam.), in 4-5 rows lower surface: pale orange-brown, attached by an umbilicus Apothecia: rare (only one found in material from Sinaloa), one to presumably several, immersed with an orange colored; disc: slightly protruding when mature asci: obclavate, I- (but the material was to scanty to be sure!) ascospores: numerous (>64) in asci, ellipsoid to bacilliform, 4.4-8 x 2.9-4.4 µm Pycnidia: not observed Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on acidic rocks and drainage areas where calcium may accumulate in secondary deposits World distribution: South Africa, Pakistan, SW North America Sonoran distribution: desert and other semiarid areas of Arizona, California, Sonora, Chihuahua and Sinaloa.