Indigofera macrocalyx is an annual plant with straggly or suberect stems that are somewhat woody and copiously branched from the base; the plant can grow 30 - 45cm tall[
The plant is harvested from the wild for local use as a medicine.
West tropical Africa - Senegal to Nigeria and Chad
Wooded savannah on sand; fields; alluvial terrace of streams; sandy plateau; sandy-clayey soil slightly humid; at elevations up to 915 metres[
Indigoera 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.
A decoction of the dried inflorescences, to which lime juice and salt have been added, is administered in draughts as a purgative[
The stems and leaves are used as a stimulant and to treat conditions such as malaria, constipation, sexual impotence[
An aqueous acetone extract of the leaves and stems is rich in polyphenols and flavonoids and has been shown to be an effective antioxidant[
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.
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