PULSE FAMILY - Leguminosae: Ground-nut

Apios tuberosa (A. Apios)

Flowers--Fragrant, chocolate brown and reddish purple, numerous, about 1/2 in. long, clustered in racemes from the leaf axils. Calyx 2-lipped, corolla papilionaceous, the broad standard petal turned backward, the keel sickle-shaped; stamens within it 9 and 1. Stem: From tuberous, edible rootstock; climbing, slender, several feet long, the juice milky. Leaves: Compounded of 5 to 7 ovate leaflets. Fruit: A leathery, slightly curved pod, 2 to 4 in. long.

Preferred Habitat--Twining about undergrowth and thickets in moist or wet ground.

Flowering Season--July-September.

Distribution--New Brunswick to Ontario, south to the Gulf states and Kansas.

No one knows better than the omnivorous "barefoot boy" that
  "Where the ground-nut trails its vine"

there is hidden something really good to eat under the soft, moist soil where legions of royal fern, usually standing guard above it, must be crushed before he digs up the coveted tubers. He would be the last to confuse it with the Wild Kidney Bean or Bean Vine (Phaseolus polystachyus). The latter has loose racemes of smaller purple flowers and leaflets in threes; nevertheless it is often confounded with the ground-nut vine by older naturalists whose knowledge was "learned of schools."