thin and smooth or becoming chinky-areolate and somewhat dispersed, margins indistinct, areolae rounded or flat, yellowish or roseate white; lacking soredia or isidia. Fertile areolae
4-5 mm broad, appearing as if apothecia of a Lecanora, projecting above thallus, sometimes containing only a single apothecium, but often developing to contain a number which are deeply embedded, with small pale ostioles showing in folds of upper side, forming a rosette-like fruit, underside almost umbilicate; hypothecium pale to dark brown; epihymenium
pale to yellow-brown or dark brown, K—; hymenium
hyaline to pink; spores
8 (sometimes 4 or 6), mainly biseriate, spore walls double, both thin, outer and inner each 1-2 μm thick, smooth and without thickened tips, ovoid to ellipsoid, 16-74 X 9-45 μm.
Reactions: cortex K—, C—, KC—, P-, UV—; medulla K—, C+ red, KC+ red, UV+, P-.
Contents: gyrophoric, variolaric, and alectoronic acids.
This species grows on rocks. It is North American arctic, ranging from Alaska to Ellesmere Island.
Brodo (1988) divides the material into two subspecies as follows: