Perennial rather tall fern with creeping woody, almost black rhizome and erect rounded stem. Leaves on long petioles, most often in whorls of three, dense, light green, triangular; lobes of the second order are oblong, pinnatipartite at the base. In spring, young leaves are twisted at the top; in summer, sporangia are found along the edges of the leaf lobes, merging into a continuous line under the curled edge of the leaf.
A widespread plant found in pine, spruce and birch forests, on dry slopes and sparse shrubs.
In folk medicine, the roots and aerial part of the plant are used. The rhizome contains hydrocyanic and eagle-tannic acids, alkaloids, essential oil and pteraquiline.
The rhizome is boiled and drunk for stomach pains, a decoction of the whole plant is used for tapeworms; a decoction of the aerial part of the plant – with aching joints, cough.