Erect annual, mostly 1–4 dm; scales below the spikes mucronate; spikes 2–10 cm, the joints 2–3.5 × 4.5–6 mm; lateral fls nearly contiguous below the lateral angles of the larger central one; seeds 1–1.5 mm. Salt marshes; N.S. to Tex.; also in Calif., Mex., and W.I.
A herb. It grows each year from seed.