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

Thallus: crustose, forming rosettes up to 2 cm in diam., often distinctly wrinkled, sometimes partly loose from the substrate, delimited, stratified with a medulla and a leprose upper surface, along margin sometimes with poorly defined lobes up to 1 mm wide and 0.6 mm thick upper surface: pale bluish gray; s oredia: coarse, up to 0.2 mm in diam., compact to fluffy, without or with shortly projecting hyphae except for those along the thallus margin which may have long projecting hyphae medulla: white, indistinct to distinct, with numerous crystals not dissolving in K, with hyphae 3-4 µm wide lower surface: sometimes evident, white to pale brown, without a tomentum or with scattered, pale brown hyphae Spot tests: thallus K- or K+ yellowish, C+ red, KC+ red, P- Secondary metabolites: atranorin (in variable amounts), and lecanoric acid (major). Substrate and distribution: on bark (Quercus), rock (rhyolite), and on soil in oak groves, on shaded cliffs, in north-facing coves, and in crevices under rock overhangs World distribution: North America Sonoran distribution: Arizona at 1650-2000 m. Notes: In the genus Lepraria, lecanoric acid is a rare substance previously known only from the recently described L. atrotomentosa Orange & Wolseley from Sri Lanka and Japan (Orange et al., 2001). Lepraria atrotomentosa is distinct from L. lecanorica chemically by producing zeorin in addition to lecanoric acid and atranorin, and morphologically in having a well-developed layer (tomentum) of dark bluish gray to dark brown hyphae on the lower side, and a thin thallus (up to 100 µm thick) .