Squamules: up to 5 mm wide, elongate, adnate to imbricate, weakly concave to weakly convex; upper surface: castaneous to dark brown, dull or shiny, epruinose or partly pruinose, sparingly to strongly fissured; margin: concolorous with upper side, straight or up-turned, crenulate to lobed; upper cortex: up to 60-120 μm thick, composed of thick-walled hyphae with more or less angular lumina, not containing crystals of lichen substances, sometimes containing calcium oxalate; medulla: not containing lichen substances or calcium oxalate; lower cortex: of mainly periclinally oriented hyphae, not containing calcium oxalate; lower surface: medium brown, K-; Apothecia: up to 1.5 mm diam., laminal, immarginate or marginate when young and later becoming immarginate, dark brown to black, epruinose or yellow pruinose; ascospores: 10-13 x 5-7 μm; Pycnidia: laminal, immersed; conidia: bacilliform, 6-9 x 1 μm; Spot tests: upper cortex and medulla K-, C-, KC-, P-; Secondary metabolites: none.
The species is close to the acid deficient species P. himalayana and P. luridella; see those for discussions. Psora californica and P. hyporubescens contain gyrophoric acid (and other compounds), and especially the latter is morphologically very similar to P. globifera, but the chemistry is diagnostic.
In the temperate zone of Asia, Europe, and North America; rare in the Arctic.
On soil or in crevices of rock in open habitat.
Psora californica, Psora himalayana, Psora hyporubescens, Psora luridella.
