Indigofera
Indigofera tinctoria
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Indigofereae
Genus: Indigofera
L. (1753)
Type species
Indigofera tinctoria
L.
Species

See text.

Synonyms[1][2]
  • Acanthonotus Benth. (1849)
  • Amecarpus Benth. (1847)
  • Bremontiera DC. (1825)
  • Brissonia Neck. (1790), opus utique oppr.
  • Eleimanthus Hochst. (1846)
  • Elasmocarpus Hochst. ex Chiov. (1903 publ. 1902)
  • Hemispadon Endl. (1832)
  • Indigo Adans. (1763)
  • Oustropis G.Don (1832)
  • Sphaeridiophorum Desv. (1813)
  • Tricoilendus Raf. (1837)
  • Vaughania S.Moore (1920)

Indigofera is a large genus of over 750 species[3] of flowering plants belonging to the pea family Fabaceae. They are widely distributed throughout the tropical and subtropical regions of the world.[3][2]

Description

Indigofera is a varied genus that has shown unique characteristics making it an interesting candidate as a potential perennial crop.[clarification needed] 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 smallholder 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 shrubs, though some are small trees or herbaceous perennials or annuals. The branches are covered with silky hairs. Most of them have pinnate leaves made of three foliolates with short petioles.[3][4]: 341 

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.[4]: 341  Indigofera flowers have open carpels, their organ primordial[clarification needed] is often formed at deeper layers than other eudicots.[5] This variety could have significant implications on its role in an actual perennial polyculture. For example, different flowering morphologies could be artificially selected for in varying directions in order to better fit in different environmental conditions and with different populations of other plants.

Fruit

The fruit is a long, cylindrical legume pod of varying size and shape.[3][4]: 341 

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 microcarpa, Indigofera suffruticosa, and Indigofera enneaphylla have shown delayed dehiscence (maturing) of fruits[6] This variation could again allow for artificial selection of the most abundant and nutritious fruit types and shapes.

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.[7] Similar to fruit shape, the variation in fruit sizes allows for the thickest and most bountiful fruits to be selected.

Uses

Indigo dye

Several species, especially Indigofera tinctoria and Indigofera suffruticosa, are used to produce the dye indigo. 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.[8] Colonial planters in the Caribbean grew indigo and transplanted its cultivation when they settled in the colony of South Carolina and North Carolina where people of the Tuscarora confederacy adopted the dyeing process for head wraps and clothing. Exports of the crop did not expand until the mid-to late 18th century. When Eliza Lucas Pinckney and enslaved Africans successfully cultivated new strains near Charleston it became the second most important cash crop in the colony (after rice) before the American Revolution. It comprised more than one-third of all exports in value.

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 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[clarification needed] during the Middle Ages.[9][10]

Species

Indigofera comprises the following species:[11][3][12][13][14]

Palaeotropical clade

Indigofera bracteolata
Indigofera hilaris

Pantropical clade

Indigofera astragalina
Indigofera australis
Indigofera decora
Indigofera hirsuta
Indigofera sanguinea
Indigofera suffruticosa

Cape clade

Indigofera cytisoides

Tethyan clade

Indigofera spicata
Indigofera cordifolia
Indigofera dalzellii
Indigofera linifolia
Indigofera trifoliata

Unassigned

Indigofera aspalathoides
Indigofera basedowii
Indigofera comosa
Indigofera hendecaphylla
Indigofera micrantha
Indigofera monophylla
Indigofera szechuensis
Indigofera procumbens
Indigofera pseudotinctoria

Species names with uncertain taxonomic status

The status of the following species is unresolved:[13][14]

Indigofera psammophila
Indigofera sylvatica

Ecology

Indigofera species are used as food plants by the larvae of some Lepidoptera species, including the turnip moth (Agrotis segetum).

See also

References

  1. ^ Schrire BD. (2008). "The Madagascan genus Vaughania is reduced to synonymy under Indigofera (Leguminosae–Papilionoideae–Indigofereae)". Kew Bulletin. 63 (3): 477–479. doi:10.1007/s12225-008-9061-7. JSTOR 20649585. S2CID 43308210.
  2. ^ a b "Indigofera L." Plants of the World Online. Royal Botanic Gardens, Kew. 2023. Retrieved 2 September 2023.
  3. ^ a b c d e Gao X, Schrire BD. "Indigofera L." Flora of China. eFloras (Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA). Retrieved 12 February 2017.
  4. ^ a b c Allen, O. N.; Allen, Ethel K. (1981). The Leguminosae, a source book of characteristics, uses, and nodulation. Madison, Wisconsin, USA: University of Wisconsin Press. pp. 341–351. ISBN 978-0-299-08400-4.
  5. ^ Paulino J, Groppo M, Teixeira S. (2011). "Floral developmental morphology of three Indigofera species (Leguminosae) and its systematic significance within Papilionoideae". Plant Systematics and Evolution. 292 (3): 165–176. doi:10.1007/s00606-010-0405-z. S2CID 23296068.((cite journal)): CS1 maint: multiple names: authors list (link)
  6. ^ Leite V, Marquiafável F, Moraes D, Teixeira S. (2009). "Fruit anatomy of Neotropical species of Indigofera (Leguminosae, Papilionoideae) with functional and taxonomic implications". The Journal of the Torrey Botanical Society. 136 (2): 203–211. doi:10.3159/08-RA-106.1. S2CID 86776541.((cite journal)): CS1 maint: multiple names: authors list (link)
  7. ^ Chauhan V, Pandey A. (2014). "Structure and evolution of the pod in Indigofera (Fabaceae) reveals a trend towards small thin indehiscent pods". Botanical Journal of the Linnean Society. 176 (2): 260–276. doi:10.1111/boj.12203.
  8. ^ Splitstoser JC, Wouters J, Claro A. (2016). "Early pre-Hispanic use of indigo blue in Peru". Science Advances. Vol. 2, no. 9. American Association for the Advancement of Science. doi:10.1126/sciadv.1501623.((cite news)): CS1 maint: multiple names: authors list (link)
  9. ^ Douma M. "Pigments through the Ages—History—Indigo". Pigments through the Ages.
  10. ^ Buchanan R. (1999). A Weaver's Garden: Growing Plants for Natural Dyes and Fibers. Courier Corporation. p. 106. ISBN 978-0-486-40712-8. Retrieved 12 May 2016.
  11. ^ Schrire BD, Lavin M, Barker NP, Forest F. (2009). "Phylogeny of the tribe Indigofereae (Leguminosae-Papilionoideae): Geographically structured more in succulent-rich and temperate settings than in grass-rich environments". Am J Bot. 96 (4): 816–52. doi:10.3732/ajb.0800185. PMID 21628237.((cite journal)): CS1 maint: multiple names: authors list (link)
  12. ^ "ILDIS LegumeWeb entry for Indigofera". International Legume Database & Information Service. Cardiff School of Computer Science & Informatics. Retrieved 12 February 2017.
  13. ^ a b USDA, ARS, National Genetic Resources Program. "GRIN species records of Indigofera". Germplasm Resources Information Network—(GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved 12 February 2017.((cite web)): CS1 maint: multiple names: authors list (link)
  14. ^ a b "The Plant List entry for Indigofera". The Plant List. Royal Botanic Gardens, Kew and the Missouri Botanical Garden. 2013. Retrieved 12 February 2017.
  15. ^ English Names for Korean Native Plants (PDF). Pocheon: Korea National Arboretum. 2015. p. 497. ISBN 978-89-97450-98-5. Archived from the original (PDF) on 25 May 2017. Retrieved 19 December 2016 – via Korea Forest Service.

Further reading