Taprooted, glabrous perennial to 1 m, often branched; lvs flat, pale green or glaucous, narrowly lanceolate, long-tapering at both ends; infl 1–3 dm, the few ascending branches usually subtended by linear lvs; pedicels 2–4 mm, jointed near the base; valves thick, triangular, 3–6 mm long and wide, acute or subacute; grains 3, lanceolate, acute, half to two-thirds as long as the valve; 2n=20 (ours), 40. Moist, often brackish or saline soil; Que. to B.C., s. to N.Y., Pa., Ky., Mo., and Mex. (R. mexicanus, a southwestern tetraploid) Our plants, as here described, are sometimes segregated as var. triangulivalvis (Danser) Hickman. (R. t.)
A herb.