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Psora nitida Timdal
Family: Psoraceae
Psora nitida image
Robin Schoeninger  
Squamules: up to 5 mm wide, rounded, adnate, dispersed to adjacent, usually concave upper surface: castaneous brown, shiny, epruinose, smooth or sparingly fissured margin: concolorous with upper side, down-turned, entire or lobed upper cortex: up to 60-80 µm thick, composed of thin-walled hyphae with round lumina, not containing crystals of lichen substances or calcium oxalate medulla: containing crystals of lichen substances but no calcium oxalate lower cortex: of mainly periclinally oriented hyphae, not containing calcium oxalate lower surface: white to pale brown Apothecia: up to 1 mm diam., marginal, immarginate even when young, black, epruinose ascospores: ellipsoid to broadly ellipsoid, 8-13 x 5-7 µm Pycnidia: laminal, immersed conidia: bacilliform, 5-7 x 1 µm Spot tests: upper cortex K-, C-, KC-, P-; medulla K-, C+ red, KC+ red, P- Secondary metabolites: gyrophoric acid and trace of lecanoric acid. Substrate and ecology: on soil in Vizcaíno subdivision of Sonoran Desert, often in hillsides, up to 400 m World and Sonoran distribution: rare in Baja California.