butterfly pea

:  any of several large-flowered wild peas of the closely related genera Clitoria and Centrosema: such as a :  a common twining vine (Clitoria mariana) of the southeastern and central U.S. with pale blue 2-inch flowers having very large standards b :  a weakly twining to prostrate vine (Centrosema virginianum) occurring from New Jersey to tropical eastern North America and sometimes cultivated for its purple and white flowers