Indigofera trita subsp. scabra
(Asian Indigo)

Pictures

Picture	Title	Caption	Copyright
Title Flowering habit Caption Indigofera trita subsp. scabra (Asian Indigo); flowering habit. Florida, USA. Copyright ©Roger L. Hammer-2015	Flowering habit	Indigofera trita subsp. scabra (Asian Indigo); flowering habit. Florida, USA.	©Roger L. Hammer-2015
Title Flower Caption Indigofera trita subsp. scabra (Asian Indigo); close-up of a flower. Crawl Key, Monroe County, Florida, USA. April, 2007. Copyright ©Keith A. Bradley-2007	Flower	Indigofera trita subsp. scabra (Asian Indigo); close-up of a flower. Crawl Key, Monroe County, Florida, USA. April, 2007.	©Keith A. Bradley-2007
Title Flower Caption Indigofera trita subsp. scabra (Asian Indigo); close-up of a flower. Note developing seed pods. Crawl Key, Monroe County, Florida, USA. April, 2007. Copyright ©Keith A. Bradley-2007	Flower	Indigofera trita subsp. scabra (Asian Indigo); close-up of a flower. Note developing seed pods. Crawl Key, Monroe County, Florida, USA. April, 2007.	©Keith A. Bradley-2007

Identity

Preferred Scientific Name

• Indigofera trita subsp. scabra (Roth) De Kort & G.Thijsse

Preferred Common Name

• Asian Indigo

Other Scientific Names

• Indigofera keyensis Small
• Indigofera laotica Gagnep.
• Indigofera mucronata var. keyensis (Small) Isely
• Indigofera rutschuruensis De Wild.

International Common Names

• Spanish: añil; azulita; frijolillo; frijolillo de llano

Local Common Names

• India: three-leaved indigo
• USA/Florida: Florida indigo

Summary of Invasiveness

To date, I. trita subsp scabra is listed as invasive only for the Dominican Republic (Kairo et al., 2003). Here, the subspecies is reported as a weed in ruderal areas, along roadsides and in disturbed forests (Kairo et al., 2003). 

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Fabales
•                         Family: Fabaceae
•                             Subfamily: Faboideae
•                                 Genus: Indigofera
•                                     Species: Indigofera trita subsp. scabra

Notes on Taxonomy and Nomenclature

Fabaceae is one of the largest families of flowering plants. This family includes about 745 genera and 19500 species which can be found throughout the world growing in a great variety of climates and environments (Stevens, 2012). The genus Indigofera includes over 750 species of shrubs, shrublets, perennial herbs, or rarely annual herbs or small trees (Flora of China Editorial Committee, 2014). Within the species I. trita, there are four infraspecific taxa accepted:

•      Indigofera trita var. maffei (Chiov.) Ali
•      Indigofera trita var. marginulata (Wight & Arn.) Sanjappa
•      Indigofera trita subsp. scabra (Roth) De Kort & G.Thijsse
•      Indigofera trita var. subulata (Poir.) Ali

The subspecies I. trita subsp. scabra is considered native to India, Laos, Sri Lanka, Thailand, and Madagascar (ILDIS, 2014). This subspecies is also listed as native and with a conservation status of endangered in Florida (USA). It has previously been known as Indigofera mucronata var. keyensis, associated with its presence in the Florida Keys.

Description

Erect, woody herbs or shrublets, 30-200 cm high; branches erect to horizontal, pinkish to light green, coarsely strigose, biramous hairs short, white, adpressed with equal arms. Leaves long, 5-7-foliolate, often basal leaves 3-foliolate; stipules 1-2 x 0.3-0.5 mm, narrowly triangular, hairy outside; petioles 1-2.5 cm long, canaliculate above, hairy; rachis 5-12 mm long; stipellae absent; petiolules 1-1.5 mm long; leaflets 3, very rarely 5, opposite. Racemes 5-15 cm long. Flowers pink to brick red, 4-5 mm long; bracts 1-1.5 mm long, narrowly triangular, caduceus; pedicels up to 1.2 mm long. Calyx adpressed white pubescent, cup 0.5-1 mm long, teeth 1-1.5 x 0.5 mm, narrowly triangular. Standard 3.5-4.5 x 3-4 mm, orbicular, sometimes broadly obovate, rounded and mucronate at apex, adpressed strigose on the back; wing petals 3-4 x 1 mm, glabrous ciliate along margins; keel petals 3-4 x 1-1.5 mm, strigose outside towards the tip, ciliate along margins, lateral spur ca 0.6 mm long. Staminal sheath 3-4 mm long; anthers approximately 0.5 mm long. Ovary approximately 3 mm long, linear, glabrous, up to 10-ovuled; style 1-1.5 mm long, glabrous. Pods more than 3 cm long, curved, dropping; seeds 6-10, approximately 2 x 1.5 mm, subtetragonous, yellow, dark-brown, smooth (India Biodiversity, 2014).

Plant Type

Distribution

The subspecies I. trita subsp. scabra is considered native to India, Laos, Sri Lanka, Thailand, and Madagascar (ILDIS, 2014). It is also listed as native to Florida (USA) (Wunderlin and Hansen, 2008). It is now uncommon in Florida, where it is extirpated on mainland Florida and present on eight islands in the upper and middle Florida Keys, in Monroe County (US Fish and Wildlife Service, 2008). Outside its native distribution range, I. trita subsp. scabra is known to occur only in Cuba, the Dominican Republic, Haiti and Jamaica (Acevedo-Rodríguez and Strong, 2012). 

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

Many species in the genus Indigofera have been introduced throughout the tropics to be used as ornamentals, forage, groundcovers, and medicinal herbs (PROTA, 2014). I. trita subsp. scabra was probably introduced in the West Indies to be used as a forage and ground cover species but there is no known date of introduction available for this region (PROTA, 2014). 

Risk of Introduction

The risk of introduction of I. trita subsp. scabra is moderate to low. Because it has a relative small geographical distribution, the probability of this subspecies colonizing new areas could be considered as “limited” (PROTA, 2014). 

Habitat

I. trita subsp. scabra grows as a weed in grassy areas, disturbed sites, along roadsides, and in open forests, forest edges, and coastal areas (ILDIS, 2014; PROTA, 2014). In Florida, this plant occurs in coastal rock barrens, ecotone rock barren areas, and scraped areas mimicking rock barren habitat (US Fish and Wildlife Service, 2008). Florida populations are vulnerable to habitat loss and degradation from exotic plants on all sites.

Habitat List

Biology and Ecology

In India, this species has been reported flowering and fruiting from September to January (India Biodiversity, 2014). 

Climate

Soil Tolerances

Soil drainage

• free

Soil reaction

• neutral

Soil texture

• light
• medium

Pathway Causes

Pathway Vectors

Impact Summary

Environmental Impact

I. trita subsp. scabra is considered weedy and invasive in the Dominican Republic where it is invading open ground, ruderal areas, disturbed sites and forest edges (Kairo et al., 2003). 

Risk and Impact Factors

• Proved invasive outside its native range
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Fast growing

• Altered trophic level
• Modification of nutrient regime
• Modification of successional patterns
• Monoculture formation
• Reduced native biodiversity
• Threat to/ loss of native species

• Competition - monopolizing resources
• Induces hypersensitivity
• Rapid growth

• Highly likely to be transported internationally deliberately

Uses

I. trita subsp. scabra is used as a forage and ground cover plant in the West Indies. It is also planted as an ornamental (Kairo et al., 2003; PROTA, 2014). 

Uses List

Animal feed, fodder, forage

• Forage

Environmental

• Erosion control or dune stabilization

Ornamental

• Cut flower
• Seed trade

References

Acevedo-Rodríguez P; Strong MT, 2012. Catalogue of the Seed Plants of the West Indies. Smithsonian Contributions to Botany, 98:1192 pp. Washington DC, USA: Smithsonian Institution. http://botany.si.edu/Antilles/WestIndies/catalog.htm

Bradley KA; Woodmansee SW; Gann GD, 2004. Status survey of aboriginal pricklyapples, Harrisia aboriginum Small ex Britton & Rose, in Southwestern Florida. Vero Beach, Florida, USA: United States Fish and Wildlife Service, South Florida Ecosystem Office. http://regionalconservation.org/ircs/pdf/publications/2004_06.pdf

Flora of China Editorial Committee, 2014. Flora of China. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=2

ILDIS, 2014. International Legume Database and Information Service. Reading, UK: School of Plant Sciences, University of Reading. http://www.ildis.org/

India Biodiversity, 2014. Online Portal of India Biodiversity. http://indiabiodiversity.org/species/list

Kairo M; Ali B; Cheesman O; Haysom K; Murphy S, 2003. Invasive species threats in the Caribbean region. Report to the Nature Conservancy. Curepe, Trinidad and Tobago: CAB International, 132 pp. http://www.issg.org/database/species/reference_files/Kairo%20et%20al,%202003.pdf

PROTA, 2014. PROTA4U web database. Grubben GJH, Denton OA, eds. Wageningen, Netherlands: Plant Resources of Tropical Africa. http://www.prota4u.org/search.asp

Stevens PF, 2012. Angiosperm Phylogeny Website. http://www.mobot.org/MOBOT/research/APweb/

US Fish and Wildlife Service, 2008. Endangered and Threatened Wildlife and Plants; Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions. Federal Register:75176 -75244. https://federalregister.gov/a/E8-28986

Wunderlin RP; Hansen BF, 2008. Atlas of Florida Vascular Plants. Tampa, Florida, USA: University of South Florida. http://www.plantatlas.usf.edu/

Distribution References

Acevedo-Rodríguez P, Strong M T, 2012. Catalogue of the Seed Plants of the West Indies. Washington, DC, USA: Smithsonian Institution. 1192 pp. http://botany.si.edu/Antilles/WestIndies/catalog.htm

CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

ILDIS, 2014. International Legume Database and Information Service., Reading, UK: School of Plant Sciences, University of Reading. http://www.ildis.org/

Kairo M, Ali B, Cheesman O, Haysom K, Murphy S, 2003. Invasive species threats in the Caribbean region. Report to the Nature Conservancy. In: Invasive species threats in the Caribbean region. Report to the Nature Conservancy. Curepe, Trinidad and Tobago: CAB International. 132 pp. http://www.issg.org/database/species/reference_files/Kairo%20et%20al,%202003.pdf

Wunderlin RP, Hansen BF, 2008. Atlas of Florida Vascular Plants., Tampa, Florida, USA: University of South Florida. http://www.plantatlas.usf.edu/

Links to Websites

Contributors

25/11/14 Original text by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA

Pedro Acevedo-Rodríguez, Department of Botany-Smithsonian NMNH, Washington DC, USA

Distribution Maps