wisteria or wistaria, any plant of the genus Wisteria, woody twining vines of the family Leguminosae (pulse family), cultivated and highly esteemed for the beautiful pendent clusters of pealike flowers, lilac, white, or pink. There are two species (W. frutescens and W. macrostachya) native to the United States, found mostly in the Southeast, but the showier Asian species are the most commonly cultivated. One variety of the Japanese wisteria (W. floribunda var. macrobotrys) has flower clusters up to 3 ft (1 m) long. Wisteria is classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Leguminosae.