Arctoa hyperborea

(Gunnerus ex Withering) Bruch & Schimper

Bryol. Europ. 1: 157. 1846,.

Basionym: Bryum hyperboreum Gunnerus ex Withering Syst. Arr. Brit. Pl. ed. 4, 3: 811. 1801
Synonyms: Cynodontium hyperboreum (Gunnerus ex Withering) Hagen Dicranum hyperboreum (Gunnerus ex Withering) Smith
Treatment appears in FNA Volume 27. Treatment on page 363. Mentioned on page 362.

Plants in compact, dark green tufts. Stems 1–3(–5) cm. Leaves erect-spreading, lanceolate, subulate, 2–3 mm; costa 30–55 µm wide at base, short-excurrent, rough near tip; distal laminal cells mostly subquadrate (1–2:1), incrassate; basal laminal cells elongate, alar cells differentiated, quadrate or slightly enlarged. Seta 4–6(–8) mm. Capsule exserted, slightly curved, obscurely to distinctly ribbed when dry, annulus developed, separating; peristome large, not spreading outward when dry. Spores 18–30 µm.

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.

Selected References


Lower Taxa