Butterfly-pea

Clitoria mariana, the Atlantic pigeonwings or butterfly-pea, is a perennial herbaceous legume in the Fabaceae with ascending, sometimes twining stems 45 to 60 centimeters long arising from a woody rootstock. The leaves are pinnately trifoliate with ovate leaflets 2.5 to 11 centimeters long and 1.5 to 5 centimeters wide, borne on petioles with persistent stipules. Showy pale-purple to lavender flowers, about 5 centimeters long, are produced axillary in summer, usually solitary and resupinate (the standard petal held downward) with a tubular calyx. The fruit is a linear-oblong pod about 25 millimeters long and 5 millimeters wide containing several seeds. The species occupies dry to moist sandy soils in open woodlands and pine barrens in high-light or partially shaded situations, ranging across the eastern, southern and central United States west to New Mexico and Arizona, with a disjunct distribution in southern China and tropical Asia from Bhutan through Myanmar, Laos, Thailand and Vietnam.