Fabaceae : Apios americana

Apios americana is a perennial herbaceous vine growing from slender rhizomes that produce tubers that get up 6 cm in diameter. The stems grow to 5 m long and climb or sprawl over shrubs and trees. The compound pinnate leaves are inserted in an alternate pattern, having deciduous stipules that are 5-7 mm long. The leaves usually have 5-7 leaflets that are ovate to lance-ovate and rounded at the base, with petioles that are 1.5-8 cm long. Flowers are organized in racemes that have a short peduncle (2-5 cm long) and are found in the axils of leaves. The calices are tubular with the lower lobe triangular and up to halve as long as the tube. The corolla is papilionaceous 10-14 mm long, with the banner reflexed, whitish dorsally and reddish ventrally. The wings are brown to purple, downcurved, and the keel is reddish brown. There are 10 diadelphous stamens, and the legume is straight to slightly curved 5-50 mm by 4-6 mm.