Swainson pea

General: Herbaceous perennial from extensive, woody rhizomes, the stems 4-9 dm. tall, arising singly or several together.
Leaves: Leaves odd-pinnate, leaflets 9-25, elliptic-oblanceolate or oblong-elliptic, 1-2 cm. long, pale, glabrous at least above; stipules linear, 2-7 mm. long.
Flowers: Inflorescence of axillary racemes, loosely 5- to12-flowered, bracteate, the peduncles about equaling the leaves; calyx bell-shaped, 5-toothed, with 2 basal bracteoles about 1 mm. long; corolla brick red to pinkish-brown, pea-like, banner and wings equal length, 10-15 mm. long; style sparsely hairy on the upper side.
Fruits: Pod membranous, inflated, 1.5-3 mm. long and 1-1.5 mm. broad, with a stipe as long to twice as long as the calyx.