Family: Fabaceae, Pea view all from this family
Description A twining vine with 2 kinds of flowers.
Habit: native, annual or perennial, vine or herb; twining or trailing; may form large colonies.
Height: stems to 5 ft (1.5 m) long.
Leaf: alternate, 3 leaflets, broadly oval to triangular.
Flowers: on upper branches, pale blue-violet to lilac to pale pink to white, 4-lobed tube, stalked, to 0.5 in (12 mm) long, held in drooping cluster from leaf axils; below (sometimes underground, inconspicuous, lacking petals.
Fruit: on upper branches, flat pod, to 1.5 in (4 cm) long; below (sometimes underground), round, edible, peanut-like.
Flower August to October.
Habitat Moist sites: woodlands, thickets, moist slopes, meadows, prairies; sometimes cultivated as an ornamental.
Range Manitoba east to Nova Scotia, south to Florida, west to Texas, and north to North Dakota and Montana.
Discussion Two varieties are proposed. Threatened in New Hampshire. The genus name is from the Greek amphi (of both kinds) and carpos (fruit) and refers to the two kinds of fruit.
The seeds of the upper fruit are inedible, but those from the underground fruit are edible when boiled. Birds feed on the seeds of both kinds of fruit. Hogs eat the seeds of the fruit below ground, hence the plants common name.