Black beans are classified as legumes. Also known as turtle beans because of their hard, shell-like appearance, black beans are, in fact, the edible seeds of the plant. Like other legumes, such as peanuts, peas, and lentils, black beans are prized for their high protein and fiber content.
The black turtle bean is a small, shiny variety of the common bean especially popular in Latin American cuisine, though it can also be found in the Cajun and Creole cuisines of south Louisiana. Like all varieties of the common bean, it is native to the Americas, but has been introduced around the world.