Distribution: East of the Cascades in Washington; throughout the United States and adjacent portions of Canada and Mexico.
Habitat: Stream banks and moist bottom lands, mostly at low elevations.
Conservation Status: Not of concern
Perennial herbs from rhizomes, the solitary stems erect, square, 2-10 dm. tall, hairy throughout.
Leaves opposite, the lower early-deciduous, the others short-petiolate, the blades serrate, lance-ovate to lance-oblong, 3-10 cm. long and 1-4 cm. wide.
Inflorescence a spike-like raceme 5-20 cm. long, with slender bracts under 1 cm. long; calyx 5-7 mm. long, the 3 upper teeth deltoid, the 2 lower longer and awl-shaped; corolla purplish, 11-18 mm. long, cleft between the two upper lobes to the mouth of the calyx, appearing to have one large, rounded upper lobe and two pairs of lateral, small, pointed lobes; stamens 4, exerted, the lower pair the longer; style 2-parted; ovary 2-celled, superior.
Fruit of 4 nutlets which are laterally attached and almost completely united.