Indigofera L.

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Habit

Herbs, shrubs or small trees

Ecology

Seasonally dry tropical to warm temperate forest, woodland, wooded grassland and grassland, sclerophyllous shrubland, forest margins and disturbed areas

Distribution

Africa-Madagascar (c. 490 spp.); Asia to Pacific (c. 115 spp.); Australasia (c. 30-40 spp.); c. 13 spp. widespread in the Palaeotropics; c. 6 spp. pantropical; New World c. 45 spp. USA to Argentina (c. 30 spp. in N & C America, c. 15 spp. in S America)

Note

A genus of c. 25 sections in Africa-Madagascar where Indigofera is most diverse, increasing to c. 30 sections worldwide; all species belong to one of four well-supported and biogeographically distinctive clades in the analyses of Schrire et al. (2003)

Polhill (1981f) recognised 4 genera and c. 710 species in Indigofereae. This treatment following Polhill (1994), Schrire (1995), Barker et al. (2000) and Schrire et al. (2003) recognises 7 genera and c. 768 species in the tribe (Fig. 44). The Indigofereae are predominantly African-Madagascan in distribution, occurring in seasonally dry vegetation types of the tropics and subtropics. The genus Indigofera (third largest in the Leguminosae) is pantropical in distribution.

Recent morphological-molecular analyses (Pennington et al., 2000a; Crisp et al., 2000; Wojciechowski et al., 2000, 2004; Hu, 2000; Kajita et al., 2001; Hu et al., 2002 and Wojciechowski, 2003) place Indigofereae at the base of a combined millettioid group of tribes (including Millettieae, Abreae, Phaseoleae, Desmodieae and Psoraleeae). This entire clade is sister to Hologalegina (comprising the robinioids and the Inverted Repeat Lacking Clade (IRLC)). Basally branching to these two clades are the South African Hypocalypteae and Australian tribes Mirbelieae and Bossiaeeae.

The Indigofereae (Barker et al., 2000; Schrire et al., 2003) comprises a Cyamopsis, Indigastrum, Microcharis and Rhynchotropis (CRIM) clade which is sister to the Indigofera-Vaughania clade. The Madagascan Phylloxylon is putatively the most basally branching genus in the tribe, although in some analyses in Schrire et al. (2003), Phylloxylon is sister to the CRIM clade.

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Herbs or shrubs, often with strigose pubescence, the hairs attached by the middle; leaves pinnate with a terminal leaflet, rarely 3-foliolate or 1-foliolate; stipules small, subulate, slightly adnate to the petioles

Morphology Reproductive morphology Inflorescences

Racemes axillary; calyx 5-lobed, the lobes sometimes unequal; standard broad or roundish, sessile or short-clawed, strigillose outside; keel usually spurred on each side near the base

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10, the uppermost free, the others united into a sheath

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary sessile; style bent upward, with capitate stigma; ovules 1–many

Morphology Reproductive morphology Fruits

Pods narrow, subcylindrical, 2-valved but usually opening along the upper suture only, partitioned inside.

Distribution

A pantropical genus of more than 300 species, most abundant in Africa.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Herbs or shrubs with biramous hairs

Morphology Leaves

Leaves usually imparipinnate, sometimes 1–3-foliolate or simple

Morphology Reproductive morphology Inflorescences

Flowers usually in axillary racemes

Morphology Reproductive morphology Flowers Corolla

Corolla usually red or pink, falling quickly, or sometimes the standard persistent; standard almost always pubescent, usually indistinctly veined; keel with lateral spurs

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Vexillary filament free; anthers almost always apiculate

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigma terminal, capitate

Morphology Reproductive morphology Fruits

Pod cylindrical, 4-angled or flattened, usually dehiscent, 1–many-seeded.

Distribution

Some 700 species in tropical and subtropical areas, but absent from the Mediterranean region.

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Habit

Trees and shrubs

Ecology

Seasonally dry tropical forest, woodland, xerophytic bushland and grassland, on sand or rocky (often limestone) outcrops and riverine

Distribution

Madagascar (S, SW, W and C)

Note

Recent molecular evidence (Barker et al., 2000; Schrire et al., 2003) places Vaughania, together with the anomalous Réunion Island endemic Indigofera ammoxylum (DC.) Polhill (= Bremontiera ammoxylum DC.), as elements within Indigofera; both are considered to be highly modified, Indian Ocean Island, neo-endemic lineages of Indigofera, but formalising the transfer of Vaughania into synonymy awaits further study

Use

Several species, particularly I. arrecta, I. articulata, I. coerulea and I. tinctoria, were once of international importance as the source of the blue-black dye indigo,butnow they are only used locally.

Use

The extremely hard wood is used for fuel, poles, implements and construction; other uses are fodder for livestock