Sweet pea is a flowering plant in the genus Lathyrus in the family Fabaceae (legumes), native to the Sicily, southern Italy and the Aegean Islands.
It is an annual climbing plant, growing to a height of 1–2 meters, where suitable support is available. The leaves are pinnate with two leaflets and a terminal tendril, which twines around supporting plants and structures helping the sweet pea to climb. The flowers are purple, 2-3.5 centimeters broad, in the wild plant, larger and very variable in color in the many cultivars. Source