Velvet bean in Kawal Wildlife Sanctuary, India
Mucuna pruriens flowers (colored engraving)
The plant is an annual climbing shrub with long vines that can reach over 15 metres (50 ft) in length. When the plant is young, it is almost completely covered with fuzzy hairs, but when older, it is almost completely free of hairs. The leaves are tripinnate, ovate, reverse ovate, rhombus-shaped or widely ovate. The sides of the leaves are often heavily grooved and the tips are pointy. In young M. pruriens plants, both sides of the leaves have hairs. The stems of the leaflets are two to three millimeters long (approximately one tenth of an inch). Additional adjacent leaves are present and are about 5 millimetres (0.2 in) long.
The flower heads take the form of axially arrayed panicles. They are 15–32 centimetres (6–13 in) long and have two or three, or many flowers. The accompanying leaves are about 12.5 millimetres (0.5 in) long, the flower stand axes are from 2.5–5 millimetres (0.1–0.2 in). The bell is 7.5–9 millimetres (0.3–0.4 in) long and silky. The sepals are longer or of the same length as the shuttles. The crown is purplish or white. The flag is 1.5 millimetres (0.06 in) long. The wings are 2.5–3.8 centimetres (1.0–1.5 in) long.
In the fruit-ripening stage, a 4–13 centimetres (2–5 in) long, 1–2 centimetres (0.4–0.8 in) wide, unwinged, leguminous fruit develops. There is a ridge along the length of the fruit. The husk is very hairy and carries up to seven seeds. The seeds are flattened uniform ellipsoids, 1–1.9 centimetres (0.4–0.7 in) long, .8–1.3 centimetres (0.3–0.5 in) wide and 4–6.5 centimetres (2–3 in) thick. The hilum, the base of the funiculus (connection between placenta and plant seeds) is a surrounded by a significant arillus (fleshy seed shell).
Mucuna pruriens seeds of two different colors
Mucuna pruriens seed pod
In many parts of the world Mucuna pruriens is used as an important forage, fallow and green manure crop. Since the plant is a legume, it fixes nitrogen and fertilizes soil. In Indonesia, particularly Java, the beans are eaten and widely known as 'Benguk'. The beans can also be fermented to form a food similar to tempe and known as Benguk tempe or 'tempe Benguk'.
M. pruriens is a widespread fodder plant in the tropics. To that end, the whole plant is fed to animals as silage, dried hay or dried seeds. M. pruriens silage contains 11-23% crude protein, 35-40% crude fiber, and the dried beans 20-35% crude protein. It also has use in the countries of Benin and Vietnam as a biological control for problematic Imperata cylindrica grass. M. pruriens is said to not be invasive outside its cultivated area. However, the plant is invasive within conservation areas of South Florida, where it frequently invades disturbed land and rockland hammock edge habitats. Cooked fresh shoots or beans can also be eaten. The plant contains relatively high (3–7% dry weight) levels of L-DOPA; some people are sensitive to L-DOPA and may experience nausea, vomiting, cramping, arrhythmias, and hypotension. Up to 88% of the L-DOPA can be extracted from M. pruriens by boiling and soaking for approximately 48 hours. The efficiency of the process can be slightly improved by using approximately 0.25-0.50% sodium bicarbonate