Helm bean

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Helm bean
Helmet Bean (Lablab purpureus)

Helmet Bean ( Lablab purpureus )

Order : Fabales (Fabales)
Family : Legumes (Fabaceae)
Subfamily : Butterflies (Faboideae)
Tribe : Phaseoleae
Genre : Lablab
Type : Helm bean
Scientific name of the  genus
Scientific name of the  species
Lablab purpureus
( L. ) Sweet

The lablab ( Lablab purpureus ), also Indian bean or Egyptian bean , hyacinth bean, formerly Fasel bean called, is the only species of the genus lablab in the subfamily Pea (Faboideae) within the family of legumes (Fabaceae or Leguminosae). This crop is closely related to a number of other crops called beans .


It is very likely that the helm bean originated in (south) eastern Africa , because wild plants of the species are only found there. In India the greatest morphological diversity of the crop on the other hand to watch. As a tropical plant, it needs high temperatures (> 20 ° C) but relatively little water; in particular, it does not tolerate waterlogging.


Illustration of the Helmet Bean ( Lablab purpureus ).

The helm bean is a strongly overgrown, semi-upright to climbing herbaceous plant that grows up to 10 m wide (in a temperate climate usually around 2 m). It is persistent, but is usually cultivated as an annual plant because, like most beans, it cannot tolerate frost. It forms a strong taproot up to 2 m deep. The stems are often very hairy. The alternate leaves are stalked and tripartite. The stipules are bent back.

On an axillary, up to 20 cm long stalk there are racemose inflorescences . The pleasantly fragrant flowers are zygomorphic and hermaphrodite. The sepals are fused. The calyx is two-lipped; the upper calyx lip is not divided, the lower is three-lobed. The petals are pink to purple or white. The single carpel contains several ovules . Flowering begins in Europe from June.

The purple-red legumes of the ornamental varieties are almost 20 cm long and contain many seeds. The egg-shaped seeds are a good 1 cm long and 0.5 cm thick. The spotted, marbled or monochrome seeds are white to red-brown to black. The thousand grain weight is between 140 and 600 grams. The typical bushy early varieties grown in India are white flowering and have rather light seed colors (white, beige, light brown).

Seeds and pods of many varieties are poisonous in the raw state because they contain cyanogenic glycosides . The poison is destroyed by boiling. However, there are big differences in varieties.

The number of chromosomes is 2n = 22.



The broad bean can be used in many ways: You can eat the unripe pods and seeds as well as the ripe seeds cooked. The plant is also used as a ground cover and green manure for soil improvement. In Europe and North America, because of its fragrant, purple flowers, it is used as an ornamental plant to border fences or as a privacy screen. used. Leaves and stems are used as fodder in the tropics. It is also important as a medicinal plant in Africa as well as in East Asia.

In Kenya , the njahĩ called helm bean is very popular throughout the country, especially among the Kikuyu . It has a reputation for stimulating milk production and is therefore traditionally a main meal of nursing mothers. The beans are boiled and mixed with must have ripe and / or semi-ripe bananas, which gives the dish a sweet taste. Nowadays, the production of the helm bean in eastern Africa is declining in favor of beans ( Phaseolus vulgaris ) and cowpeas ( Vigna unguiculata ). This decrease is z. In part, however, it is also attributed to the fact that Kenyan farmers were forced to give up their traditional (helmet) beans in the colonial era for the production of dry beans ( Phaseolus vulgaris ), which were intended for export.


The genus Lablab belongs to the subtribe Phaseolinae of the tribe Phaseoleae in the subfamily butterfly family (Faboideae) within the family of legumes (Fabaceae).

The generic name Lablab was published in 1763 by Michel Adanson in Familles des plantes , 2: 325. The species was first described in 1753 under the name Dolichos lablab by Carl von Linné in Sp. Pl. , 725. The British biologist and taxonomist Bernard Verdcourt subjected the species to a revision in 1970, whereupon many of the earlier names are now synonymous. Even so, the name Dolichos lablab still persists in scientific and popular science publications.

Synonyms of Lablab purpureus (L.) Sweet are: Dolichos lablab L. , Lablab niger Medik. , Lablab lablab (L.) Lyons , Vigna aristata Piper , Lablab vulgaris (L.) Savi .

According to Verdcourt, there are two cultivated subspecies of Lablab purpureus (L.) Sweet :

  • Lablab purpureus subsp. bengalensis (Jacq.) Verdc. (Syn .: Dolichos bengalensis Jacq. , Dolichos lablab subsp. Bengalensis (Jacq.) Rivals , Lablab niger subsp. Bengalensis (Jacq.) Cuf. )
  • Lablab purpureus subsp. purpureus

There is also a wild subspecies:

  • Lablab purpureus subsp. uncinatus Verdc. ,

of which a special variant with lobed leaves only occurs in Namibia:

  • Lablab purpureus var. Rhomboïdeus (Schinz) Verdc.

See also

Web links

Commons : Helmbohne  - Collection of images, videos and audio files

Individual evidence

  1. a b Brigitte L. Maass, Maggie R. Knox, SC Venkatesha, Tefera Tolera Angessa, Stefan Ramme, Bruce C. Pengelly: Lablab purpureus (L.) Sweet - a crop lost for Africa? . In: Tropical Plant Biology . 3, No. 3, 2010, pp. 123-35. doi : 10.1007 / s12042-010-9046-1 .
  2. ^ Dolichos bean, Lablab purpureus (L.) Sweet by the University of Agricultural Sciences, Bangalore, India
  3. Sebastian Guretzki, Jutta Papenbrock: Characterization of Lablab purpureus Regarding drought tolerance, trypsin inhibitor activity and cyanogenic potential for selection in breeding programs. . In: Journal of Agronomy and Crop Science . 200, No. 1, 2014, pp. 24-35. doi : 10.1111 / jac.12043 .
  4. Lablab purpureus at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
  5. ^ John Smartt: Evolution of grain legumes. II. Old and new world pulses of lesser economic importance. . In: Experimental Agriculture . 21, No. 3, 1985, pp. 1-18. doi : 10.1017 / S0014479700012205 .
  6. G. Shivashankar, RS Kulkarni: van der Maesen, Sadikin Somaatmadja (Ed.): Plant Resources of South-East Asia, No. 1, pulse . Pudoc, Wageningen, The Netherlands 1992, pp. 48-50.
  7. ^ A b PROTA (Plant Resources of Tropical Africa). (No longer available online.) Archived from the original on January 10, 2016 ; accessed on September 28, 2018 .
  8. ^ A b Patrick M. Maundu, GW Ngugi, Christine HS Kabuye: Traditional food plants of Kenya. . National Museums of Kenya , English Press, Nairobi, Kenya, 1999.
  9. ^ Claire C. Robertson: Black, white, and red all over: Beans, women, and agricultural imperialism in twentieth-century Kenya. . In: Agricultural History . 71, No. 3, 1997, pp. 259-99.
  10. ^ Lablab in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  11. a b Bernard Verdcourt: Lablab Adans. In: Studies in the Leguminosae-Papilionoideae for the 'Flora of Tropical East Africa': III. . In: Kew Bulletin . 24, No. 3, 1970, pp. 409-11.