Pea

An annual herb with a soft stem that climbs by tendrils, 0.5–2 m tall depending on the cultivar. The pinnate leaves usually have one to three pairs of leaflets and end in branched tendrils; the stipules are large. The flowers are typical of the legume family (banner, two wings, keel), white, pink or purple, and usually self-pollinate before opening. The fruit is a thin-walled legume pod 5–10 cm long holding four to ten spherical seeds, each weighing 0.1–0.36 g, green (fresh) or yellow (dry). There are cultivars eaten as whole young pods (snow peas, sugar peas), cultivars for fresh seeds and cultivars for dry grain.

The pea originates in the Mediterranean and southwest Asia and was domesticated very early (ancient seeds found in the Middle East and Europe). Gregor Mendel used Pisum sativum to study crosses and discovered the laws of heredity (Mendelian inheritance) thanks to its ease of self-pollination, clear contrasting traits, large flowers that are easy to handle, and abundant offspring. Today it is grown worldwide as a cool-season food crop. In Vietnam, peas are grown in the winter–spring season in the north and in Đà Lạt; young pods are eaten whole (stir-fried, boiled, in soups) and fresh seeds are used in many dishes.