Inga (T. D. Pennington, RBG Kew, 1997)


Inga vera ssp. vera (photo by C.E. Hughes)

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Approximately 50% of species are confined to rain forest on non-flooded land, while the remaining 50% occur in riparian situations, on periodically flooded land and in disturbed vegetation. Although most abundant in non-seasonal climates, they also extend into seasonally dry areas, such as Pacific coastal Ecuador. In arid zones they are restricted to a few species along periodic water-courses.

The genus Inga (Leguminosae: Mimosoideae: Ingeae) comprises 258 described species of trees restricted to tropical America. It is a ubiquitous component of lowland and montane rain forest throughout the humid tropical zone from 24 degrees north in Mexico to 34 degrees south in Uruguay. The highest species diversity is concentrated in the Andean foothills of Peru, Ecuador , Colombia and in southern Central America., and within this area it occupies a wide variety of habitats from sea level to 3000m altitude.

Inga has been utilized by man for its edible fruit for several thousand years and today it is still an important item of local commerce throughout the Andean countries, Central America and lowland South America.


Over the centuries selected forms of certain species have been protected and cultivated, so that they are now recognizable as distinct cultivars, which have been carried far from their centre of origin. Inga species also have a long history of utilization as shade trees, originally used by pre-Colombian in habitants of Peru as shade for coca bushes, and since the mid nineteenth century as shade for coffee, cacao and tea. Throughout Andean South America, many thousand of hectares of these crops still depend on Inga, not only for their shade but also for the leaf mulch, which provides weed control and nutrients, for their nitrogen fixing properties and for fuelwood from their periodic pruning.

More recently, Inga has been recognized as one of the few legumes in tropical America which will survive and flourish on the impoverished acidic red soils which cover much of the land surface of the region, and much research effort is now focused on the restoration of these soils which support much farming activity after the cutting of rain forest. It is now recognized that Inga has an important role in agroforestry systems which are designed to bring back degraded acid soils into productive use, and Inga species are being prioritized by the International Centre for Research in Agroforestry (ICRAF) working in Amazonian Peru.

Publications associated with this database

  • Pennington, T.D. The genus Inga. Botany. Royal Botanic Gardens, Kew pp 1-844 (1997)
  • Reynel, C. & Pennington, T.D. El genero Inga en el Peru. Royal Botanic Gardens, Kew pp 1-228 (1997)
  • Pennington, T.D. & Revelo,N. El genero Inga en el Ecuador. Royal Botanic Gardens, Kew pp 177 (1997)
  • Pennington, T.D. & Fernandes, E.C.M. (eds.) The genus Inga. Utilization. Royal Botanic Gardens, Kew pp 177 (1998)