Indigofera coerulea

Roxb.

Fabaceae Edible: Fruit 41 iNaturalist observations

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Description

A herb. It grows 1 m tall. The leaves are compound with leaflets along the stalk. There are 5-9 leaflets. They are 32 mm long and 23 mm wide. They are hairy underneath. The fruit is curved and with 3-4 segments.

Edible Uses

The fruit is eaten.

Medicinal Uses

The dried, ground up leaves and roots are used as a wound dressing. A paste made from the leaves is used in the treatment of jaundice. An extract of the leaves is drunk as a remedy for constipation and is applied as a wash against infected eyes.

Distribution

It is a tropical plant.

Where It Grows

Africa, Asia, Ethiopia, Pakistan,

Cultivation

A plant of arid and semi-arid tropical and subtropical areas, where it is found at elevations from 200 - 2,700 metres. It can be found in areas where the mean annual rainfall is as low as 200 - 250mm. Indigofera species generally grow best in a sunny position, preferring a well-drained but moist soil. Many of the species will also succeed in drier conditions and in poor soils. We have seen no specific information for this species, but most members of the genus have a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby.

Propagation

Seed - it has a hard seedcoat and may benefit from scarification before sowing in order to speed up and improve germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing.

Other Uses

All the above-ground parts of the plant are a source of the dye indigo, which is used to colour textiles blue. The leaves and twigs do not actually contain indigo but colourless precursors that must be extracted and then processed in order to produce the indigo dye. The harvested leafy branches are placed in a tank containing water to which some lime has been added, and are weighted down with planks. After some hours of fermentation, during which enzymic hydrolysis leads to the formation of indoxyl, the liquid is drained off and then stirred continuously for several hours to stimulate oxidation of the indoxyl. Afterwards the solution is left to rest and the insoluble indigo settles to the bottom as a bluish sludge. The water is drained and after the indigo has dried, it is cut into cubes or made into balls. To dye textiles, indigo is reduced to a soluble form by a fermentation process under alkaline conditions. In traditional preparations of the dye, various reducing agents such as molasses are used, together with coconut-milk, bananas and the leaves of Psidium guajava. The alkalinity is maintained by adding lime. After the textile has been dipped into solution it turns blue when exposed to the air.

Synonyms

Indigofera argentea var. brachycarpa VatkeIndigofera argentea var. coerulea (Roxb.) Baker

Also Known As

Adulala

References (1)

Bahru, T., et al, 2013, Wild Edible Plants: Sustainable Use and Management by Indigenous Communities in and the Buffer Area of Awah National Park, Ethiopia. Ethiop. J. Sci., 36(2): 93-108