Legumes

Many species in the legume family are indigenous to the natural plant communities of North America. Numerous other species of legumes have been introduced by humans from Eurasia, Africa, and elsewhere and are now naturalized in suitable habitats in North America. The introduced plants are mostly species that are grown in agriculture or horticulture and were able to escape from cultivation and establish wild populations.

Native species of legumes are among the most beautiful and engaging wildflowers of North America. Some of the most interesting and attractive groups of native legumes include the wild lupines (such as Lupinus perennis), false blue indigo (Baptisia australis), wild indigo (B. tinctoria), tick-trefoils (Desmodium spp.), bush-clovers (Lespedeza spp.), beach pea (Lathyrus maritimus) and marsh pea (L. palustris), milk-vetches, and loco-weeds (Oxytropis spp.).

Some North American examples of tree-sized legumes that occur in temperate climates include the black locust (Robinia pseudoacacia), yellow-wood (Cladrastis lutea), redbud (Cercis canadensis), honey locust (Gleditsia triacanthos), and Kentucky coffee tree (Gymnocladus dioica). These are all native to parts of the eastern United States but are cultivated as ornamentals more widely, sometimes escaping into roadside and secondary-forest habitats.

Other native species of legumes occur in subtropical habitats in the southern United States. These include the eastern coralbean (Erythrina herbacea) of the southeastern states, Bahama lysiloma (Lysiloma bahamensis), and fish-poison tree (Piscidia piscipula) of southern Florida. Subtropical legumes in the southwestern states include cattail acacia (Acacia greggii), sweet acacia (A. farnesiana), and other acacias, along with species of leadtrees (Leucaena spp.) and blackbeads (Pithecellobium spp.).