Spurred Butterfly Pea, a native species, has been added to the USWildflowers database (10/29/2013.) Scientific name is Centrosema virginianum. Photo below was taken at Camp Vesper Point in Hamilton County, TN on August 17, 2013.  Go to the Spurred Butterfly Pea detail page for more photos and information.

Spurred Butterfly Pea – Centrosema virginianum