Rhizomatous perennial to 1.5 m, often rooting from the swollen nodes; lvs lanceolate, acuminate, mostly 10-25 נ2-5 cm; ocreae smooth, entire or nearly so, not fringed; peduncles strigulose; racemes slender, to 10 cm; ocreolae obconic, truncate, scarcely oblique, commonly overlapping; perianth white, 2.5-3 mm, enlarging to 3-4 mm, conspicuously surpassing the fr, this black, 2-2.5 mm, 70-100% as wide, strongly biconvex. Swamps and shallow water of the coastal plain; s. N.J. to Fla. and Tex., n. in the interior to s. Mo.; W.I. and S. Amer. (Persicaria portoricensis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.