Indigofera polyphylla DC.
Indigofera virgata Roxb.
Indigofera simlensis Ali
Indigofera dosua is a shrub with erect branches; it can grow 5 - 20cm tall[
]. It can grow 50 - 250cm tall according to other reports[
The plant is harvested from the wild for local use as a food, medicine and a dye. The plant is sometimes cultivated for local use as an indigo-yielding dye plant in Assam[
E. Asia - southern China (Yunnan), India, Nepal, Bhutan, Myanmar, Thailand, Laos, Vietnam, Indonesia
Valley slopes; at elevations from 1,800 - 2,500 metres[
]. Evergreen forest, open pine forest, secondary vegetation and grassland; at elevations from 800 - 2,400 metres[
|Other Uses Rating||
|Cultivation Status||Cultivated, Wild
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.
This species has 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.
Flowers - used as a kitchen herb[
The leaves are irritant and purgative. They are pulverized then used to treat inflammation of the liver[
The leaves are applied topically to treat boils[
The root is said to have vermifugal propertie[
The foliage has sometimes been used as a source of indigo, a much-used blue dye obtained commercially from species such as Indigofera arrecta and Indigofera tinctoria[
The leaves and twigs of Indigofera species do not actually contain indigo, but rather they contain 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[
Like many species within the family Fabaceae, once they have been dried for storage the seeds of this species 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[
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