Adder's-tongue Fern

Overview

Ophioglossum vulgatum is native to Europe, including Britain, from Iceland south and east to north Africa, north and west Asia. The name Ophioglossum comes from the Greek meaning "snake-tongue", because the tall stalk that bears its spores is thought to resemble a snake's tongue. It is harvested from the wild for local use as a food and medicine. It has long been used in the European folk medicine: extracts of leaves were known in Great Britain as “Green oil of charity”. The leaf is edible and used as a vegetable. 

Vernacular Names

Herbe sans couture (French).

Agroecology

Can be found on damp grassland, fens and scrub. Prefers a moist free-draining soil, with pH of 5.5-6.5. Grows best in temperature of 12-18 °C. Plants are hardy to about -15 °C.

Morphology

• Rhizome - short, linear to oval, 1-3 cm long; old leaf bases absent; roots horizontal, proliferous. 
• Leaves - dark green and ovate, abruptly tapering at base; fertile spike erect and tall, arising from leaf base, slightly widened at top. Petiole up to 16 cm long, subterranean for 25-50 % of its length. Sterile lamina 25-90 × 9-40 mm, ovate to sometimes lanceolate in outline, apex pointed, base wedge-shaped, sometimes with a pseudo-petiole up to 2 cm long; fertile segment 8-16.5 cm long, slender.
• Sporangia - 19-46 pairs, apex pointed.

Cultivation

• Propagated by spores - best sown as soon as they are ripe on the surface of a humus-rich sterilized soil. Keep the compost moist, preferably by putting a plastic bag over the pot. Pot on small clumps of plantlets as soon as they are large enough to handle and keep them in humid conditions until they are well established. Do not plant outside until the ferns are at least 2 years old.
• Vegetatively propagated by division of underground rhizomes - with care because the roots are brittle.

Chemical Constituents

Quercetin 3-O-methyl ether, ophioglonin, flavonols (quercetin-3-O-[(6-caffeoyl)-β-glucopyranosyl (1 →3) α-rhamnopyranoside]-7-O-α-rhamnopyr-anoside, and kaempferol-3-O-[(6-caffeoyl)-β-glucopyranosyl (1 →3) α-rhamnopyranoside]-7-O-α-rhamnopyranoside, triglycoside 3-O-methylquercetin 7-O-diglycoside 4′-O-glycoside.

Traditional Medicinal Uses

• The root and the leaves are antiseptic, detergent, emetic, haemostatic, styptic and vulnerary.
•  An ointment made from the plant is considered to be a good remedy for wounds and is also used in the treatment of skin ulcers.
• The expressed juice of the leaves is drunk as a treatment for internal bleeding and bruising.
• In northern Italy, aerial parts of the plant were soaked in olive oil to yield an ointment that was used mainly as wound poultice.
• In India, China and southern Nigeria, the plant is used for dermatological purposes.