Psora pseudorussellii
Psora pseudorussellii photo by Mark Zloba
Psora pseudorussellii photo by Bob Klips
DIAGNOSTIC FEATURES: Can be recognized by its small, 2-3 mm wide, rounded to irregular more or less thick reddish brown squamules with light colored margins; thallus more or less clustered, adnate or marginally ascending; medulla white; lower surface white, lacking rhizines; apothecia brown, the disc convex.
ECOLOGY: Found on calcareous rocks.