Inga

Mill., 1754

shimbillo, ice-cream-bean, guama, guaba, guaba de bejuco, paterna

Species Guides

3

Inga is a of small tropical nitrogen-fixing trees and shrubs in the legume Fabaceae, Mimosoideae. The genus comprises approximately 300 , most native to the Amazon forest region, with others distributed across Mexico, the Greater and Lesser Antilles, and other parts of South America. Inga species are characterized by pinnate leaves, generally white flowers, and distinctive bean-like pods containing seeds covered in sweet, edible white pulp. The genus is exclusively neotropical and has significant economic and ecological importance, particularly in agroforestry systems.

Pronunciation

How to pronounce Inga: /ˈɪŋɡə/

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Identification

Distinguished from other Fabaceae by combination of: pinnate leaves, white flowers, nitrogen-fixing root nodules, and distinctive long pods with sweet white pulp surrounding seeds. Within the genus, identification requires examination of pod length, flower , and geographic origin. Some species previously placed in Inga have been reclassified (e.g., Anadenanthera peregrina was formerly Inga niopo).

Habitat

Tropical rainforest environments, particularly along river and lake edges where seeds are deposited by floods. Requires well-drained soils. Commonly found in Amazon forest region and other neotropical lowland forests.

Distribution

Exclusively neotropical. Native to South America (primarily Amazon basin), Mexico, Greater and Lesser Antilles. Not naturally occurring outside the Americas.

Seasonality

Trees usually bloom twice yearly. Fruit production can occur almost year-round in suitable climates.

Life Cycle

Seeds dispersed by floodwaters to river and lake edges. Trees produce flowers and fruits in cycles, with blooming typically occurring twice annually and fruit production extending across much of the year.

Ecological Role

Nitrogen-fixing trees that improve soil through association with nitrogen-fixing bacteria in root nodules. Extrafloral in some attract beneficial insects that provide protection against herbivores and may extend pest control services to nearby crops. Seeds serve as food source for various animals. Decomposing leaf litter contributes to nutrient cycling in tropical .

Human Relevance

Widely used in agroforestry as shade trees for coffee, cocoa, and tea plantations. Alley cropping with Inga (notably Inga edulis and Inga oerstediana) restores soil and reduces slash-and-burn agriculture pressure on rainforests. Edible pulp of many species consumed raw; Inga edulis pulp resembles vanilla ice cream in flavor. Timber used for construction and furniture. Many species cultivated ornamentally.

Similar Taxa

  • AnadenantheraFormerly included in Inga (as Inga niopo); distinguished by different alkaloid chemistry and seed

More Details

Agroforestry significance

Research at Cambridge University by Mike Hands over 20 years developed alley cropping techniques using Inga edulis and Inga oerstediana to restore degraded tropical soils.

Etymology

name originates from Tupi word in-gá meaning 'soaked', referring to the consistency of the sweet powder covering the seeds.

Invasive fruit fly associations

Inga trees in Belize have been documented as for sucking insect pests (, whiteflies, aphids, ) that produce white waxy coatings on leaves; these in turn attract predatory assassin bugs.

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Sources and further reading