Mucuna urens (L.) Medik.

Species Identification and Growth Form

Mucuna urens (L.) Medik. is a large, vigorous, much-branched twining liana that climbs into tree canopies.

Stem and Leaf Characteristics

Its stems are thick and soft, and bear alternate trifoliate leaves with petioles that can grow up to 15 cm (6 in) long. The leaflets are ovate or elliptical, reaching up to 15 cm (6 in) long; lateral leaflets are somewhat oblique, and all leaflets have rounded bases and apiculate tips.

Inflorescence Structure

Inflorescences grow laterally or in leaf axils, forming pendulous racemes with peduncles up to 1 metre long, with flowering occurring near the tip.

Flower Morphology

The calyx has a 1 cm (0.4 in) long tube, and the petals are thick, waxy, and yellowish. The standard petal is slightly longer than the wings and keel.

Pod Structure

After flowering, the plant produces transversely-ridged, oblong pods measuring about 15 cm × 5 cm (6 in × 2 in). These pods are covered in orange-brown bristly stinging hairs, have a suture along their underside, and feature two longitudinal undulating wings.

Seed Characteristics

Each pod holds 1 to 4 rounded seeds that are at least 2.5 cm (1 in) in diameter, with a hilum that almost completely surrounds the seed.

Native Range

This liana is native to the West Indies, Central America, and South America, with its natural range extending from Panama to Peru, Ecuador, Bolivia, and Brazil.

Habitat and Altitude

It grows in forests and woodland at altitudes up to 1,800 m (6,000 ft).

Traditional Medicinal Use for Hemorrhoids

Mucuna urens is used in traditional medicine. A tincture made from powdered bean macerated in alcohol is used as a soothing remedy for hemorrhoids, especially those that tend to bleed.

Anthelmintic Use of Stinging Hairs

The stinging hairs from the pods can be taken internally to expel live intestinal worms.

Skin Irritation from Stinging Hairs

These stinging hairs are irritating to the skin: contact causes intense itching, reddening, and formation of tiny pustules soon after exposure, caused by the active proteolytic enzyme mucunain.

Water Extraction Use

Potable water can be obtained from the plant's fleshy stems.

Fibre Use

Fibres from the stem are used to make strong rope.

Seed Uses

The seeds are used to make beads and ornaments, and also serve as famine food.

Potential Anti-Fertility Application

When a seed extract was given to male guinea pigs at low dosages, it was found to cause sperm degeneration, raising the possibility that this plant could be used as a male anti-fertility agent.