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Indigofera hirsuta L. 1753
pronounced: in-dee-GOFF-er-uh her-SOO-tuh
(Fabaceae – the pea family)
subfamily: Faboideae – the bean subfamily
common name: Hairy Indigo
Indigofera is from the Spanish indigo, from the Latin indicum, the name for the plant, and fero, to bear, carry; hirsuta is from the Latin hirsutus, rough, shaggy, bristly, and tells that the plant is hairy.
Hairy Indigo occurs naturally in Africa from Senegal to the Sudan and the Congo, Zambia, Mozambique, Angola and Madagascar. It is also natural in southern Asia, and in northern Australia, particularly in Queensland. It has become naturalized in parts of tropical America.
This is an erect or spreading annual, that can grow up to 1.5 m tall, but is generally shorter. The stems are cylindrical or slightly ridged, densely clothed with long fine spreading grey or reddish brown pubescence. The stipules are linear, up to 1 cm long, and bristly. The leaves have 5–7 leaflets (occasionally 9), oblong-elliptic, up to 4 cm long and 2.5 cm wide, the terminal one rather longer than the lateral, all of them pilose on both surfaces.
The inflorescence is a dense, many-flowered raceme, hairy, 20–30 cm long including a peduncle more than 2.5 cm long. The bracts are linear-lanceolate, up to 2.5 cm long. The pedicels are only about 1 mm long, reflexed in the fruit. The calyx is stiff, brown and hairy, about 4 mm long, divided almost to the base into linear, bristly lobes. The corolla is white pubescent outside, brick red or rose inside.
The pods are straight, rather four-sided, with well-developed joints, 12–20 mm long by about 2 mm wide, thickly hairy: many of the hairs, especially the dorsal ones, are usually brown. There are 6–9 seeds, more-or-less cubic in shape, angular and strongly pitted.
As with most members of the pea family, the plant fixes nitrogen from the atmosphere and transfers it to the soil through root nodules; and in many parts of the tropical world it is grown as a crop for this purpose. It is also grown for hay, especially in Florida, but the hay must be made early in the season, as the stems become coarse and woody with age. The aftermath from such an early cut can then be grazed. The Hairy Indigo grown for farming purposes is usually one of a number of cultivars that have been developed for the purpose. As with many agricultural plants, it can easily escape, and become a weed.
This is a host plant for the caterpillars of the Grass Jewel Freyeria putli.
In the Philippines, a decoction of fresh leaves is given for stomach ache and diarrhoea; in the Gold Coast of Africa, for yaws; and in parts of India for cerebral disorders.
Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.
Photographs taken in Picnic Bay 2009, 2010, 2018
Page last updated 12th April 2018