African yam bean

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African yam bean
Sphenostylis stenocarpa seeds.jpg

African yam bean ( Sphenostylis stenocarpa )

Order : Fabales (Fabales)
Family : Legumes (Fabaceae)
Subfamily : Butterflies (Faboideae)
Tribe : Phaseoleae
Genre : Sphenostylis
Type : African yam bean
Scientific name
Sphenostylis stenocarpa
( Hochst. Ex A.Rich. ) Harms

The African yam bean ( Sphenostylis stenocarpa ) is a plant species in subfamily Pea (Faboideae) within the family of legumes (Fabaceae or Leguminosae). It is native to tropical Africa.

This crop is closely related to a number of other crops called " beans ". In the German-speaking world, the terms Rübenbohne and 'Knollenbohne' are also used . However, the type described here does not belong to the genus of yam bean ( Pachyrhizus ) and should not also with the tuber bean ( Pachyrhizus tuberosus be confused). Their exact ancestry is not known.


The African yam bean is a trailing, prostrate to upright herbaceous plant . The shoot axes reach lengths of 1.5 to 2.5 meters. The stalked leaves are threefold with egg-shaped, about 7-14 centimeters long leaflets . There are stipules present. The pink, purple or greenish-white butterfly flowers are zygomorphic .

The 20 to 30 centimeters long, slightly woody, glabrous and narrow, flat legume contains 20 to 30 seeds. The seeds are round or ellipsoidal to lens-shaped with a length of about 3.2-8 millimeters. They are creamy white, beige or orange, dark or reddish brown to black and sometimes with dark marbling.


The African yam bean grows wild throughout tropical Africa and is cultivated in Central and West Africa ( Ivory Coast , Ghana , Togo , Gabon , Democratic Republic and Republic of the Congo ) and parts of East Africa (such as Ethiopia and Zimbabwe ), but especially in southern Nigeria , where it Girigiri is called. It tolerates acidic and sandy soils and occurs at altitudes from 0 to 1800 meters. The African yam bean is dependent on a warm, humid climate and non-damming soils.

Use and ingredients

Both seed and root tubers are used as food.

The African yam bean develops tubers 5 to 7.5 centimeters long and 50 to 300 grams heavy at the roots, which look like elongated sweet potatoes but contain twice as much protein as these. The tubers have a protein content of 11 to 19% and a carbohydrate content of 63 to 73%, with 3% fiber. A harvest of half a kilogram of roots is possible per plant.

The seeds are tasty and are often preferred in West Africa to all other available seeds and vegetables. They contain 21 to 29% protein, which has lysine and methionine levels that are similar to or higher than that of soybeans . The seeds also contain around 50% carbohydrates and 5 to 6% fiber . Up to 2000 kg of beans can be harvested per hectare.

The dried beans are usually soaked in water and cooked for several hours, and then eaten without a side dish or with yams , rice , corn or in soups. The “meat” of the root tubers is used raw or cooked like potatoes , and the taste is similar.

The young leaves and legumes are eaten as vegetables.

With its large flowers, which vary in color depending on the “variety”, the African yam bean is also suitable as an ornamental plant .


  • National Academy of Sciences: Tropical Legumes: Resources for the Future. 1979, Books for Business, 2002, ISBN 0-89499-192-2 (Reprint), pp. 27-32.

See also

Web links