[3] It was first described by Carl Linnaeus in his Flora Lapponica, 1737, from specimens obtained in Finland.

The stems are upright, 4-edged, growing densely in branchy bunches.

The leaves are small, scale-like, wintering and parallel to the stem.

[4] The spore-cases are in sesile, 1-1,5 cm long, densely cylindrical spore cones.

[3] The female stems produce strobili up to 3 cm (1 in) long.