Lablab purpureus is a species of bean in the family Fabaceae. It is native to Africa and it is cultivated throughout the tropics for food. English language common names include hyacinth bean, lablab-bean bonavist bean/pea, dolichos bean, seim bean, lablab bean, Egyptian kidney bean, Indian bean, bataw and Australian pea. It is the only species in the monotypic genus Lablab.
Linn. (D.cultraius,Thunb. D. purpureus, Lindl). Hyacinth Bean.Tall-twining (often reaching 10-20 ft.): leaflets broad-ovate, rounded below and cuspidate-pointed at the apex, often crinkly: fls. purple, rather large, 2-4 at the nodes, in a long, erect raceme: pods small (2-3 in. long) and flat, usually smooth. conspicuously tipped with the persistent style; seed black, small. Tropics. B. M. 896. B. R. 10:830. A.G. 14:84. - Cult. in this country as an ornamental climbing bean, but in the tropics the seeds are eaten. Annual. It is easily grown in any good garden soil.
Like common beans, it will not endure frost. It is very variable. A form with white fls. and seeds is D. albus, Hort. A form of very large growth, also white-fld. , is D. gigantéus, Hort. (Fig. 731). A perennial form (perhaps a distinct species) is D. lignosus, Linn., the Australian Pea.
The hyacinth bean is an old domesticated pulse and multi-purpose crop. Due to seed availability of one forage cultivar (cv. Rongai), it is often grown as forage for livestock and as an ornamental plant. In addition, it is cited both as a medicinal plant and a poisonous plant.
The fruit and beans are edible if boiled well with several changes of the water. Otherwise, they are toxic due to the presence of cyanogenic glycosides, glycosides that are converted to hydrogen cyanide when consumed. Signs of poisoning include weakness, vomiting, dyspnea, twitching, stupor, and convulsions. It has been shown that there is a wide range of cyanogenic potential among the varieties.
The leaves are eaten raw or cooked like spinach. The flowers can be eaten raw or steamed. The root can be boiled or baked for food. The seeds are used to make tofu and tempeh.