Abstract: The divaricatic acid-producing populations of Lepraria in North America north of Mexico are revised with traditional morphological characters, chemistry, ecology, biogeography, and ITS1, 5.8S, and ITS2 sequence data. Three taxa are accepted: L. cryophila, L. hodkinsoniana sp. nov. and L. pacifica sp. nov. Both Lepraria crassissima and L. incana are excluded from the study area. Noncryptic, semicryptic and fully cryptic species concepts in lepraria are discussed with emphasis on the practical integration of molecular characters into taxonomic frameworks based on non-molecular characters.

Editorial remarks (CNALH: F. Bungartz, 2019): previous North American records of L. incana belong to L. hodkinsoniana.

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

Thallus: crustose, leprose, irregular, indeterminate, firmly fastened to the substrate, forming a thin layer of soredia; lobes not evident; upper surface: gray-green, blue-green or gray-blue, dull; soredia: mostly farinose, up to 70(-110) µm in diam., fluffy, sometimes with shortly projecting hyphae; medulla: absent; lower surface: not evident, without tomentum; Spot tests: thallus K- , C-, KC- , P-; UV+ bluish white; Secondary metabolites: atranorin, zeorin, divaricatic and nordivaricatic (trace accessory) acids.

Substrate and ecology: on bark, including Quercus agrifolia and Lithocarpus densiflorus; World distribution: North America; Sonoran distribution: southern California from near sea level to 400 m.