Distribution: Widely distributed throughout Washington; widely distributed throughout North America.
Habitat: Noxious weed of standing water and wet ground.
Origin: Introduced from Europe
Conservation Status: Not of concern
Herbaceous perennial from rhizomes, the stems angled, simple or branched above, 0.5-2 m. tall.
Leaves mostly opposite, but some in 3u00e2u20acu2122s or alternate, 3-10 cm. long, lanceolate, acute, somewhat cordate at base, puberulent to soft-pubescent.
Flowers in crowded, elongate, interrupted, terminal spikes, usually several per bract, sub-sessile; calyx tube purplish, 5 mm. long, the 5-7 lobes about half a long as the alternating linear appendages, which are 1.5-2 mm. long; petals 5-7, reddish-purple, 7-10 mm. long, attached at the top of the calyx tube; stamens 8-10, inserted in the calyx tube, of three different lengths, from barely to conspicuously exerted.
Capsule elongate, 2-celled.