Erect or prostrate, 1-4 dm, often freely branched; lvs opposite or whorled, linear-spatulate, 1-3(-5) cm, mostly obtuse; sep alternating with triangular appendages of nearly the same size; pet white or pink, minute, caducous; fr 3-5 mm; 2n=32. In mud or wet soil; near the coast from Mass. to Fla. and Tex.; inland from O. and Mich. to Minn., Ark., and Okla.; also on the Pacific coast, in Mexico, and trop. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.