Indigofera

Lore & Background

Indigofera species are mostly shrubs, though some are small trees or herbaceous perennials or annuals. Their branches are covered with silky hairs, and most have pinnate leaves with three foliolates. Small flowers grow in leaf axils, with petals in hues of red or purple, though a few species have greenish-white or yellow flowers. The flowers have open carpels, and their organ primordia often form at deeper layers than other eudicots. The fruit is a long, cylindrical legume pod, with variation in curvature—straight, slightly curved, or falcate—and pericarp thickness categorized as type I (thinnest), type II, or type III (thickest).

Reader's Guide

Indigofera holds significance both historically and agriculturally. Several species, especially Indigofera tinctoria and Indigofera suffruticosa, are used to produce the dye indigo. Scraps of indigo-dyed fabric from Huaca Prieta predate Egyptian indigo-dyed fabrics by more than 1,500 years. Colonial planters in the Caribbean grew indigo and later transplanted its cultivation to South Carolina and North Carolina, where the Tuscarora confederacy adopted the dyeing process. Exports expanded in the mid-to-late 18th century, and after Eliza Lucas Pinckney and enslaved Africans cultivated new strains near Charleston, indigo became the second most important cash crop in the colony after rice, comprising over one-third of all exports in value before the American Revolution. The chemical aniline was first synthesized from Indigofera suffruticosa. In Indonesia, the Sundanese use Indigofera tinctoria for batik dye. The genus also shows potential as a perennial crop due to its diverse variation in fruit type, pericarp thickness, and flowering morphology, which could be artificially selected for different environments and polyculture systems.

Did You Know?

• Indigofera is a large genus of over 750 species in the pea family Fabaceae.
• Scraps of indigo-dyed fabric from Huaca Prieta predate Egyptian indigo-dyed fabrics by more than 1,500 years.
• The chemical aniline was first synthesized from Indigofera tinctoria.
• Indigo comprised more than one-third of all exports in value from the colony of South Carolina before the American Revolution.

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