Erect annual 1-3 dm, sometimes simple, but usually with a few decussate branches; lvs chiefly in whorls of 3 or 4, linear to oblanceolate or narrowly elliptic, 1-4 cm נ1-5 mm, obtuse or rounded, often apiculate; racemes cylindric, 1-6 נ1-1.5 cm, rounded at the summit, usually sessile or nearly so; fls pale rose-purple or greenish-purple; wings deltoid, 3-4 mm wide at base, 4-6 mm long, terminating in a slender cusp 0.5-1.5 mm; 2n=36, 40. Damp or wet soil, marshes, pine-barrens, etc., chiefly but not wholly on the coastal plain; Me. to Fla. and Tex., also in Ky. and from O. and Mich. to Ill. and Minn. July-Sept. (P. ramosior)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.