The genus Inga is a large group of forest trees restricted to South America. This monograph describes and maps 258 species. Of these 253 are illustrated, and information is presented on distribution, ecology, field characteristics and species relationships. Additional chapters cover morphology, wood and bark anatomy, cytology, non-protein amino acid chemistry, flavonoid chemistry, variation, relationships and distribution, and uses. There is a full list of exsiccatae and indexes to scientific and vernacular names.