Thallus yellowish gray to white, continuous, finely cracked to chinky-areolate, even to rugulose or verruculose; margin distinct; pro-thallus weak or lacking; medulla I —; esorediate. Apothecia abundant, scattered to clustered, sessile, to 1.7 mm broad; margin thin, entire to crenulate or radially grooved; exciple black and carbonaceous, ca. 50 μm, with narrow inner hyaline region which disappears with age; hymenium 70-90 μm, hyaline; paraphyses conglutinate, anastomosing, branched in upper part; spores 12-15 x 6-9 μm.

This species grows on acidic rocks. It is low arctic North American in distribution.

Gowan (1989) places this species as analogous to the northeastern P. cinereoatra but with thinner, yellower thallus, more sessile apothecia, and more northerly distribution.