Indigo plants originate from different parts of the world. Indigofera arrecta from east and southern Africa, and I. suffruticosa from tropical America. I. tinctoria was probably native to Asia, but it has been widely distributed and is now naturalized all

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                     Indigo (Indigofera tinctoria)

 

Indigo-introduction

  • Indigofera is a large genus of about 700 species.
  • The species are mostly shrubs, though some are herbaceous, and a few can become small trees up to 5–6 m (16–20 ft) tall.
  • Most are dry-season or winter deciduous.
  • The leaves are pinnate with 5–31 leaflets and the terminal leaflet present.
  • Leaf sizes vary

From 3–25 cm (1.2–9.8 in).

  • The flowers are small, produced on racemes 2–15 cm (0.79–5.9 in) long.
  • Indigofera species are used as food plants by the larvae of some Lepidoptera species including Turnip Moth.

 

Scientific classification

 

  • Toxonomy of Plant Kingdom : Plantae
  • Division : Magnoliophyta
  • Class :Magnoliopsida 
  • Order : Fabales
  • Family : Fabaceae
  • Subfamily : Faboideae
  • Tribe : Indofereae
  • Genus : Indigofera
  • Species : L.tinctoria
  • Binomial name : Indigofera tinctoria

 

Physical Description:

                                        Shrubs, Herbs, Taproot present, Nodules present, Stems erect or ascending, Ste ms less than 1 m tall, Stems 1-2 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stems silvery, canescent, tomentose, cobwebby, or wooly, Stems with 2-branched hairs, dolabriform, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules setiform, subulate or acicular, Stipules persistent, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets 5-9, Leaflets 10-many, Leaves glabrous or nearly so, Leaves hairy on one or both surfaces, Inflorescences racemes, Inflorescences spikes or Perennial spike-like, Inflorescence axillary, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Petals separate, Corolla papilionaceous, Petals clawed, Petals pinkish to rose, Petals red, Petals orange or yellow, Banner petal ovoid or obovate, Wing petals narrow, oblanceolate to oblong, Wing petals auriculate, Wing tips obtuse or rounded, Keel petals auriculat e, spurred, or gibbous, Keel abruptly curved, or spirally coiled, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Fruit a legume, Fruit unilocular, Fruit freely dehiscent, Fruit elongate, straight, Fruit oblong or ellipsoidal, Fruit coriaceous or becoming woody, Fruit exserted from calyx, Fruit inflated or turgid, Fruit internally septate between the seeds, Fruit compressed between seeds, Fruit torulose or moniliform, strongly constricted between seeds, Fruit glabrous or glabrate, Fruit hairy, Fruit 3-10 seeded, Seeds ovoid to rounded in outline, Seed surface smooth, Seeds olive, brown, or black.

 

Indigo – history:

                                 Indigofera tinctoria was originally domesticated in India, where it is mentioned in manuscripts dating from the 4th century BC. It was recognized as a valuable blue dye by most early explorers of that region. The Venetian explorer Marco Polo described in detail the Indian indigo industry and by the 11th century, Arab traders had introduced indigo to the Mediterranean region, where it replaced their native blue dye plant, woad (Isatis tinctoria).

The use of vegetable dyes in India dates back to the Indus Valley period between the 4th and the 2nd millennium BC. The historical record of indigo is patchy, but references were made by Marco Polo who saw indigo at present day Quilon in the state of Kerala in 1298.

The cultivation of indigo on a large scale started in the 16th century in India and this was documented by European visitors in the 16th and 17th centuries, particularly in the north of India.

The British established commercial cultivation and production of indigo. Initial plantations began in 1777, and by 1788 most of the production of indigo purchased by the East India Company originated from Bengal. The system became deeply exploitative from 1837 when 'planters' were accorded permission to own land.

Vast quantities of indigo were concentrated around Bengal, particularly in the district of Champaran which is now in Bihar. This area was the focal point for processing and trade. As a dye it replaced American supplies which had been disrupted during the American Revolution. It was in great demand to supply the textile industries of the Industrial Revolution and was used to dye European military uniforms.       

The East India Company imported massive volumes of Indian indigo in the mid 1600s. Its use in Europe was clearly a threat to native woad growers. Protests led to the ban of indigo in Britain and other European countries. Despite this, European woad plantations and factories rapidly disappeared.

The chemical process of indigo dyeing was only unraveled in the 1870s, opening the way for chemical substitutes. This was catastrophic to the Indian indigo economy and it had a profound effect on the movement for independence in India. By 1914 only 4% of the total world production came from plants.

In Japan, indigo became especially important in the Edo period when it was forbidden to use silk, so the Japanese began to import and plant cotton. It was difficult to dye the cotton fiber except with indigo. Even today indigo is very much appreciated as a color for the summer Kimono Yukata, as this traditional clothing recalls Nature and the blue sea. In colonial North America there were three commercially important species: the native Indigofera caroliniana, and the introduced Indigofera tinctoria and Indigofera suffruticosa.

Newton used "indigo" to describe one of the two new primary colors he added to the five he had originally named, in his revised account of the rainbow in Lectiones Opticae of 1675.

Because of its high value as a trading commodity, indigo was often referred to as Blue Gold.

Indigo – origin:                                              

                          Indigo plants originate from different parts of the world. Indigofera arrecta from east and southern Africa,  and I. suffruticosa from tropical America. I. tinctoria was probably native to Asia, but it has been widely distributed and is now naturalized all over the tropics. The species cultivated for commerce is mainly I. tinctoria.



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