Perennial 2-6 dm, often decumbent; stipules dissected into several filiform segments 2-3 mm; lvs narrowly elliptic to lanceolate or oblanceolate, 3-8 cm, acute, tapering to a very short petiole; fls glomerate in the upper axils; sep lance-oblong, eventually 2-3 mm; cor white, 2-3 mm, densely bearded within; fr obovoid, 3 mm; 2n=28. Swamps and wet ground; se. O. to e. Kans., s. to Fla. and Tex. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.