https://plantvillage.psu.edu/topics/cowpea/infos
Cowpea, Vigna unguiculata, is a climbing annual in the family Fabaceae grown for its edible seeds and pods. The cowpea plant is usually erect and possess ribbed stems and smooth trifoliate leaves which are arranged alternately on the stems. The plant produces clusters of flowers at the end of a peduncle (flower stalk) and 2–3 seed pods per peduncle. The seed pods are smooth, cylindrical and curved, reaching up to 35 cm (10 in) in length, with distinctive coloration, usually green, purple or yellow. As the seeds reach maturity the pod changes color to tan or brown. The seeds can be white, cream, green, red brown or black in color or be a mottled combination. The seed may also possess an ‘eye’ where a lighter color is surrounded by one that is darker. Cowpea can reach in excess of 80 cm (31.5 in) in height and, as an annual plant, lives for only one growing season before harvest. Cowpea may also be referred to as black-eyed pea, southern pea, crowder pea or field pea and originates from Africa.