Penthorum sedoides L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Erect, 2–7 dm, simple or branched above, glabrous below, stipitate- glandular in the infl; lvs lanceolate to narrowly elliptic, 5–10 cm, sharply serrate, acuminate at both ends; cymes 2–8 cm; sep oblong-lanceolate; capsule 5–6 mm wide; 2n=18. Marshes and muddy soil; Me. to Ont. and Minn., s. to Fla. and Tex. July–Sept.