Pinyin: [jiāng dòu]

cowpea (scientific name Vigna unguiculata), commonly known as kidney bean, ginger bean, kidney bean and hanging kidney bean. Cowpea is divided into long cowpea and rice cowpea, belonging to leguminous plants. Cowpea is an annual plant in Leguminosae. There are three kinds of stems: dwarf, semi-tendril and tendril. The cultivation in south China is mainly vine, followed by dwarf. An annual twining herb of Papilionaceae, with 3 leaflets, terminal lobules rhomboid-ovate, 5-13 cm long and 4-7 cm wide, acute at the top, nearly round or wide wedge-shaped at the base, glabrous on both sides, and lateral lobules oblique-ovate; Stipules ovoid, about 1 cm long, with a short distance below the insertion site. Calyx campanulate, glabrous; Corolla lavender, about 2 cm long, with yellowish whiskers in the upper part of the style. Pods are linear and drooping, up to 4 cm long. The flowering and fruiting period is from June to September.

The leaves are trifoliate leaves, and pedicels with a length of 2-25 cm are drawn from the axils of the leaves. First, 2-4 pairs of flowers are born, white, red, lavender or yellow, and generally only two pods are produced. The pods are slender and vary with varieties, with a length of about 3-7 cm, and the colors are dark green, light green, red purple or red spots.

Each pod contains 16 ~ 22 seeds, which are kidney-shaped, including red, black, reddish brown, red and white, black and white seeds, etc. The root system is developed, and pink nodules are born on the roots.