Vigna

{| border="1" cellspacing="0" align="right" cellpadding="2" ! align="center" bgcolor=lightgreen | Cowpeas |- || |- ! align="center" bgcolor=lightgreen | Scientific classification |- | {| align="center" | align=left | Kingdom: || Plantae |- || Division: || Magnoliophyta |- || Class: || Magnoliopsida |- || Order: || Fabales |- || Family: || Fabaceae |- || Subfamily: || Faboideae |- || Genus: || Vigna Savi |} |- ! align="center" bgcolor="lightgreen" | Species |- | align="left" | see text |- |} The cowpeas are the genus Vigna in the plant family Fabaceae. They include some well-known and not so well known bean species formerly included in the genus Phaseolus.

ITIS accepts 20 species, some of them with several subspecies. Many of them have common names including the word "cowpea". Used on its own, however, "cowpea" refers either to the genus as a whole or to the black-eyed pea Vigna unguiculata ssp. dekindtiana.

Many references even in current literature will place some of these species in genus Phaseolus. According to Hortus Third, however, Vigna differs from Phaseolus in that

• plants in Vigna often have stipules that are appendaged
• the thickened part of the style is less strongly twisted
• details of the pollen
• details of the biochemistry

Examples of Vigna species include:

• V. acontifolia moth bean
• V. angularis azuki or adzuki bean
• V. mungo urd bean or urd
• V. radiata mung bean, green gram
• V. subterranea Bambara groundnut (placed by some authors in genus Voandzeia)
• V. umbellata rice bean
• V. unguiculata cow bean
  • V. unguiculata ssp. cylindrica Catjang
  • V. unguiculata ssp. dekindtiana Black-eyed pea
  • V. unguiculata ssp. sesquipedalis Yardlong bean
  • V. unguiculata ssp. unguiculata Southern pea
• V. vexillata zombi pea