Erect perennial 6-15 dm tall; stem stout, simple or branched, strongly
ribbed and hirsute above. Leaves pinnately 3-foliate, the leaflets dark
green above, pale beneath, ovate-lanceolate to lanceolate or occasionally obovate,
3-9 cm long, 1-3.5 cm wide, puberulent above, more densely so beneath, acute
to obtuse, sometimes apiculate; petioles 2-20 mm long; stipules linear-subulate,
4-9 mm long, ciliate. Inflorescence of 1 terminal raceme or a panicle
of several racemes, the terminal one longest, 6-20 cm long, pubescent on the
axis; bracts brownish, lanceolate, appressed-hairy, deciduous; pedicels
4-8 mm long. Flowers reddish-purple, drying dark blue, irregular; calyx
purple, deeply 5-toothed, somewhat irregular, 4-6 mm long, the lowest sepal
longest; corolla 5-9 mm long; stamens diadelphous in a 9 + 1 arrangement.
Fruits constricted between the 2-several seeds, 1.5-5 cm long, beset
with hooked hairs, ultimately breaking apart into 1-seeded segments which are
3-5 mm wide. Jul--Sep. Stream banks, pond margins, ditches, floodplains and
swampy places; occasional in e and sc ND, e, c and sw SD and most of NE; (Que.
and N.S. to Alta., s to SC, AR and OK).