Phaseolus polystachios.commons.wikimedia.org (Accessed 7/2014).

Phaseolus polystachios is a perennial twining vine, stem to 4 m long. 

Leaves alternate, 3-parted, leaflets broadly egg-shaped, terminal leaflet 3- 8 cm long, lateral leaflets asymmetric, rough-hairy above, softly hairy below. 

Flowers purple, pea-flower-shaped, about 1cm long, upper petal (standard) round, folded over the others, lower petal (keel) coiled, upper calyx lobes rounded, others broadly triangular, style coiled, hairy on upper side; inflorescence long-stalked, unbranched about 15 cm long; blooming July-Sept.

Fruit dry, hollow pod, flat 3-6 cm long, curved, splitting open to release seeds, the sides coiling, seeds 4-5, to 1 cm long, 0.6 cm wide, black to gray. 

Wetland status: NL. 

Frequency in NYC: Very infrequent. 

Origin: Native. 

Habitat: Moist to dry, open oak woods, thickets, edges, sandy soil.