Male Fern

(Dryopterisfilix-mas (L.) Schott, Polypodiaceae)

Also Called: Male Shield Fern

Description: Rhizome brownish-black, covered with the leaf bases of the previous year, the whole forming a cylinder 2050cm (8-20in) long often as thick as an arm. Leaves up to 140cm (55in) long arranged spirally, with stout stalk the lower surface of which is scaly and hairy; the central rachis bears alternate leaflets, the younger ones towards the apex. Leaflets subdivided, the smallest segments rounded and not pointed (distinction from other ferns of similar appearance, but medicinally inactive); in summer and in autumn these leaflets bear on their lower surface masses of spore-bearing sori, initially greenish-white, then brown.

Taste of rhizome: at first sweetish, then bitter and nauseous.

Part Used: Dried rhizome with remains of leaf bases.

Habitat and Collection: Widespread; abundant in Britain and Europe. Much is imported for medicinal use. Collected in autumn.

Constituents and Action: Substances active against tapeworm (filicic acid, etc.), small amounts of volatile oil, fixed oil and tannin. Large doses are toxic to man and may cause blindness.

Usage: Usually as an extract. Because of the high doses necessary to expel tapeworms it is dangerous to use male fern except under the supervision of a physician. Occasionally decoctions of the rhizome cut into small pieces are used to bathe wounds that are slow to heal.