Indigofera is a large genus of over 750 species
Description
Indigofera is a varied genus that has shown unique characteristics making it an interesting candidate as a potential perennial crop. Specifically, there is diverse variation among species with a number of unique characteristics. Some examples of this diversity include differences in pericarp thickness, fruit type, and flowering morphology. The unique characteristics it has displayed include potential for mixed smallholding systems with at least one other species and a resilience that allows for constant nitrogen uptake despite varying conditions.
Tree
Species of Indigofera are mostly , though some are small trees or herbaceous perennial plant or annual plant. The branches are covered with silky hairs. Most of them have pinnate leaves made of three foliolates with short petioles.
Small flowers grow in the leaf axils from long peduncles or spikes, their petals come in hues of red or purple, but there are a few greenish-white and yellow-flowered species.
Fruit
The fruit is a long, cylindrical legume pod of varying size and shape.
The types of fruit produced by different species of Indigofera can also be divided into broad categories that again show great variation. The three basic types of fruit categories can be separated by their curvature including straight, slightly curved, and falcate (sickle-shaped). In addition, several of the species, including Indigofera suffruticosa and Indigofera microcarpa, have shown delayed dehiscence (maturing) of fruits.
Another way to categorize Indigofera is by its pericarp thickness. The pericarp (the tissue from the ovary that surrounds the seeds) can be categorized as type I, type II, and type III with type I having the thinnest pericarp and fewest layers of schlerenchymatous (stiff) tissue and type III having the thickest pericarp and most schlerenchymatous layers. Despite the previous examples of delayed dehiscence, most fruits of this genus show normal explosive dehiscence to disperse seeds.
Species
, Plants of the World Online accepted over 760 species worldwide.
Selected species:
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Indigofera astragalina DC.
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Indigofera australis Willd.
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Indigofera candicans Aiton
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Indigofera cassioides Rottler ex DC.
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Indigofera cloiselii Drake
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Indigofera cordifolia B.Heyne ex Roth
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Indigofera decora Lindl.
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Indigofera galegoides DC.
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Indigofera georgei E.Pritz.
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Indigofera glaucescens Eckl. & Zeyh.
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Indigofera hendecaphylla Jacq.
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Indigofera heterantha Wall. ex Brandis
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Indigofera hilaris Eckl. & Zeyh.
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Indigofera himalayensis Ali
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Indigofera hirsuta L.
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Indigofera howellii Craib & W.W.Sm.
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Indigofera kirilowii Maxim. ex Palibin
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Indigofera linifolia (L.f.) Retz.
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Indigofera marmorata Balf.f.
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Indigofera miniata Ortega
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Indigofera nephrocarpoides J.B.Gillett
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Indigofera nummulariifolia (L.) Livera ex Alston
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Indigofera pendula Franch.
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Indigofera rothii Baker
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Indigofera sokotrana Vierh.
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Indigofera spicata Forssk.
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Indigofera suffruticosa Mill.
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Indigofera szechuensis Craib
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Indigofera tinctoria L.
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Indigofera tsiangiana Metcalf
Ecology
Indigofera species are used as food plants by the of some Lepidoptera species, including the turnip moth ( Agrotis segetum).
Uses
Indigo dye
Several species, especially Indigofera tinctoria and Indigofera suffruticosa, are used to produce the dye Indigo dye. Scraps of Indigo-dyed fabric likely dyed with plants from the genus Indigofera discovered at Huaca Prieta predate Egyptian indigo-dyed fabrics by more than 1,500 years.
The chemical aniline, from which many important dyes are derived, was first synthesized from Indigofera suffruticosa (syn. Indigofera anil, whence the name aniline).
In Indonesia, the Sundanese people use Indigofera tinctoria (known locally as tarum or nila) as dye for batik. Marco Polo was the first to report on the preparation of indigo in India. Indigo was quite often used in European easel painting during the Middle Ages.
See also
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Baptisia (false indigo)—a related genus.
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Amorpha fruticosa
Further reading
External links
