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

Thallus: foliose, 2-4 cm in diam., adnate, irregularly lobate lobes: irregular, +plane to somewhat wrinkled, separate, 2-3 mm wide, 100-125 µm thick; apices rotund, with dentate margins and isidiate, occasionally upturned or enclosing the moss upper surface: greenish brown, dull centrally but shiny marginally, smooth to finely striate isidia: usually dense, laminal to marginal, clavate or dactyliform, usually simple, concolorous with the thallus or darker internal anatomy: with upper and lower cortices consisting of a single layer of irregularly isodiametrical cells 8-10 µm in diam., internally with loosely interwoven chains of Nostoc and hyphae lower surface: pale to medium brown, smooth to finely striate, with scattered tufts of hairs Apothecia: not observed Pycnidia: not observed Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on moss cushions over soil or rocks in semiarid habitats World distribution: western North Amerca from British Columbia to Arizona Sonoran distribution: Arizona. Notes: In Sierk (1964) it may come closest to L. dactylinum Tuck., an eastern species occurring on wet limestone, but that species has more squamiform, bluish lobes and thinner, coralloid isidia. In the Sonoran region L. arsenei Sierk may be somewhat similar, but it is gray, grows on rocks and has much thicker lobes.