Weedy, often freely branched perennial 2-10 dm from shallow, slender, stoloniform rhizomes; herbage and hypanthium evidently spreading-setose; stems inequably and often obscurely quadrangular, the 4 raised lines delimiting 2 narrow, flat to concave sides and 2 broader, often rounded ones; principal lvs lance-elliptic to lance-linear or lance-ovate, 2-5(-8) cm, seldom more than a third as wide; hypanthium mostly 6-10(11) mm at maturity, the neck as long as or longer than the body; pet 12-18 mm, dull lavender to white; generally glabrous; anthers 5-8 mm; 2n=22, 44. Moist, open places, often in disturbed habitats; Mass. to Fla., w. to s. Ind., s. Mo., and Tex.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.