Monographs Details: Inga (L.) Britton inga
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - In his classification of plants of the Mimosa Family Linnaeus included widely diverse kinds of the genus Mimosa, distributed by subsequent, more critical authors, into several genera, of which Inga is one of the largest; we have 2 native species in Porto Rico, both large trees, which must have been plentiful in our original forests, and are yet locally abundant in wet or moist districts, owing to extensive planting for coffee-shade and for roadside trees, the one here illustrated the typical species of the genus, familiarly known as Guabá, the other, also illustrated in this work, as Guamá.
Inga (an aboriginal name, first recorded by the French botanist Plumier), was established as a genus by the Italian botanist Scopoli in 1777. As now understood, about 150 species of trees and shrubs are included, all natives of tropical America. They have once-compound leaves, with few, or several pairs of mostly broad leaflets, and variously clustered flowers. The tubular, or bell-shaped calyx is 5-toothed; the corolla is tubular, or funnelform, usually 5-lobed; the many long stamens are partly united by their filaments, and the anthers are very small; the stalkless, 1-celled ovary contains many ovules, the style is slender, the stigma terminal. The fruit is a narrow, leathery pod, variously flattened or nearly cylindric, falling away without opening.
Inga Inga (the type species) is a tree which may become 15 meters high, or higher, with a trunk up to about a meter in diameter, the bark somewhat fissued; the wood is grey, hard, strong, and rather heavy. The tree is distributed through the Greater Antilles, from Guatemala to Panama, and British Guiana, and recorded from Trinidad. The twigs, leaves and flower-clusters are hairy. The stalked leaves and from 20 to 30 centimeters long, with from 3 to 5 pairs of oblong, or elliptic, pointed leaflets about 10 centimeters long, or smaller; the leaf-axis is broadly winged between the pairs of leaflets, and bears a small, round gland between each pair. The flowers are few together in short clusters borne on stalks from 1.5 to 6 centimeters long; the velvety calyx is from 9 to 13 millimeters long, with broad, pointed teeth; the white, silky corolla is from 13 to 16 millimeters long, with pointed lobes; the white stamens are 3 or 4 times as long as the corolla. The slender, velvety, nearly cylindric, ribbed pod is from 10 to 15 centimeters long and from 8 to 15 millimeters thick.
Mimosa Inga Linnaeus, Species Plantarum 516. 1753.
Inga vera Willdenow, Species Plantarum 4: 1010. 1806.
Inga Inga Britton, Flora of Bermuda 170. 1918.