Hog-peanut

Amphicarpaea bracteata, hog-peanut, is a slender, twining herbaceous annual or short-lived perennial vine in the family Fabaceae native to deciduous forests, woodland edges, thickets, and stream banks across much of eastern and central North America. Stems are wiry, sparsely retrorsely hairy, and grow 0.5–1.5 m long, climbing on neighbouring vegetation. The alternate leaves are pinnately trifoliolate with broadly ovate to rhombic leaflets 3–8 cm long, the lateral pair somewhat oblique. The species is notable for producing two distinct kinds of flowers — its name means 'doubly fruited.' Aerial chasmogamous flowers are pale lilac to white, pea-shaped, 8–15 mm long, borne in slender axillary racemes and produce small flat, hairy, three- to four-seeded pods. In addition, inconspicuous cleistogamous (self-pollinating) flowers develop on creeping basal stems at or just below the soil surface, each maturing into a single, fleshy, edible underground seed about the size of a small peanut. These subterranean seeds were widely gathered as food.