Short answers, pulled from the story.
Indigofera is a large genus of flowering plants in the pea family Fabaceae. Plants of the World Online has accepted over 760 species, distributed across tropical and subtropical regions worldwide.
Indigofera tinctoria and Indigofera suffruticosa are the two species most commonly used to produce indigo dye. Indigofera suffruticosa was also the source from which the chemical aniline, a precursor to many synthetic dyes, was first synthesized.
Scraps of indigo-dyed fabric found at Huaca Prieta, likely dyed with plants from the genus Indigofera, predate Egyptian indigo-dyed fabrics by more than 1,500 years.
Eliza Lucas Pinckney and enslaved Africans successfully cultivated new strains of indigo near Charleston in colonial South Carolina. Their work helped make indigo the second most important cash crop in the colony after rice, comprising more than one-third of all exports by value before the American Revolution.
Indigofera shows resilience in maintaining nitrogen uptake under varying conditions and has demonstrated potential for integration in mixed smallholder systems with other species. The wide variation in flowering morphology, fruit shape, and pericarp thickness also makes it suitable for selective breeding to fit different environments.
Aniline takes its name from Indigofera anil, a historical synonym for Indigofera suffruticosa. The chemical aniline, from which many important dyes are derived, was first synthesized from that species.