Bryol. Europ. 1: 157. 1846,
Phenology: Capsules mature summer.
Habitat: Siliceous rock or soil
Elevation: high-alpine elevations
Arctoa hyperborea is a rare arctic-alpine moss found on rock ledges or crevices at high elevations. It is distinguished from other species of the genus by its short-excurrent costa, shorter seta (the length is highly variable), and peristome not spreading when dry.