Reactions: thallus K—, C+ red, KC + red, P-; disk K—, C+ red, KC+ red, P—; soredia P+ orange.
Contents: gyrophoric acid, atranorin, and two unknowns (Ahti et al. 1973).
This species grows on calcareous soil, wood, Picea bark, and rocks. It is known from Siberia, possibly Spitzbergen, and North American tundras.
This species is very closely related to O. inaequatula but has a much more abundant thallus with finer soredia.