Mucuna pruriens (L.) DC. cv. group Utilis
Family
Leguminosae
Synonyms
Mucuna utilis Wall. ex Wight, Mucuna pruriens (L.) DC. var. utilis (Wall. ex Wight) Baker ex Burck, Mucuna pruriens (L.) DC. f. utilis (Wall. ex Wight) Backer.
Vernacular Names
|
Malaysia |
Kacang babi, kekaras gatal. |
|
English |
Velvet bean. |
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American |
Cowitch. |
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Indonesia |
Kara benguk (Javanese), kowas (Sundanese), kekara juleh (Moluccas). |
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Philippines |
Sabawel. |
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Cambodia |
Khnhae. |
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Laos |
Tam nhe. |
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Thailand |
Mamui (central). |
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Vietnam |
D[aaj]u m[ef]o r[uf]ng. |
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French |
Pois mascate, pois velus. |
Geographical Distributions
Mucuna pruriens is probably a native of tropical South or Southeast Asia, and has been widely distributed throughout the tropics. It was introduced into Florida in 1876, from where its range was extended into temperate and subtropical areas by breeding. In the south-eastern United States, it used to be the most important cover crop grown in combination with maize in an area of about 1 000 000 ha around 1920. Later, soya bean and commercial fertilisers rapidly replaced it and it disappeared from agricultural statistics in 1965. As a cover crop, it is now most important in Australia, Hawaii, the Fiji Islands, Indonesia, Malaysia and the Philippines.
Description
Mucuna pruriens is a vigorous, climbing, pubescent annual herb which can grow up to 2-18 m long. The roots are numerous, 7-10 m long and with many lateral taproots. The stem is slender, cylindrical, slightly pubescent with white, straight, short and long hairs and nearly hairless.
The 3-foliolate leaves are arranged alternate. The stipules are 0.5 cm long, caducous, subulate, white-hairy outside and hairless inside. The petiole is (3-)4-9(-13.5) cm long, slightly grooved above and generally slightly pubescent. The rachis is (0.5-)1-2 cm long, grooved above and slightly pubescent. The stipels are slender. The lateral leaflets are conspicuously asymmetrical, obovate, rhombic, ovate or elliptical, measuring (5-)7-15(-19) cm x (3- )5-12( -17) cm and with symmetrical terminal leaflets. The apex is acute to acuminate-mucronate, rounded at base, and covered with appressed, grey or silvery hairs that turn black when dry.
The inflorescence is an axillary raceme, up to 32 cm long, 1-many-flowered and silvery pubescent. The tubercled rachis is without lateral branchlets. The bracts are 5-10 mm long, early caducous and narrowly triangular-elliptical. The pedicel is 1.5-10 mm long, and with two bracteoles measuring 10 mm x 2 mm near the base of the sepal. The sepal is bell-shaped, with tube 4-7 mm long, 5-lobed, appressed silvery pubescent outside and hairless inside. The upper pair of lobes is connate while the other 3 lobes are subequal, triangular, measure 3-9 mm long and acute. The petal is blackish-purple, pale lilac or white. It is clawed and auricled. The upper part of it is hood-shaped, much shorter than other petals, measuring 17-22 mm x 11-15 mm, fleshy especially towards the base and rounded at the top. The wings are narrowly obovate, measuring 32-35 mm x 8-10 mm, fleshy especially towards the base, rounded at the top and finely and patently pubescent at the base. The keel measures about 35 mm x 5 mm, narrow in the middle, entirely split dorsally, ciliolate at the edges, nearly hairless towards the top, ventrally split near the base and apex, with apical part hard and ending in a horny tip. The 10 stamens are in two bundles.
The fruit is an oblong, (1-)3(-7)seeded pod with oblique top, somewhat compressed laterally, slightly bulging over the seeds, measuring 4-13 cm x 1-2 cm and finely pubescent with white to light brown hairs. The valves are thick and leathery, with prominent, complete rib and with 2-3 partial and less prominent ribs.
The seed is oblong-ellipsoid, somewhat laterally compressed, measuring about 15 mm x 10 mm x 5 mm and with variable colour. It is light or pinkish-brown with dark brown mosaic, mottled with grey, purple or black background, almost entirely black, grey, greyish-black or white. The hilum is oblong, lateral, eccentric, measures about 4 mm long, surrounded by a prominent, cream-coloured aril and with scale-like extension at the rim. Seedling is with hypogeal germination.
Ecology / Cultivation
Mucuna pruriens tolerates a wide range of annual rainfall from 400-3000 mm, but is not drought resistant because of its shallow root system. Only Mauritius bean shows better drought tolerance. M. pruriens grows best at an average annual temperature of 19-27°C. Plants are sensitive to frost and exposure to a temperature below 5°C for more than 24 hours is fatal even for cultivars from Florida. A night temperature of over 21°C is said to stimulate flowering. M. pruriens requires a high light intensity and yields poorly when intercropped with cassava or maize. It grows best on well-drained sand and clay soils and on ultisols with a pH of 5-6.5, but also grows vigorously on acidic sandy soils. It does not tolerate waterlogging. In soils with a fertile topsoil and an acidic subsoil, the latter being low in P and high in AI, root growth is concentrated in the topsoil. If a fertile topsoil is absent, an extensive root system develops even in acidic soils.
Line Drawing / Photograph
Read More
1) Western Herb
2) South Central America Herbs
References
1. Plant Resources of South-East Asia No.11: Auxiliary plants.
