Stems erect, green sometimes becoming red, simple or with primary and secondary branches, 5-60 cm, ultimate branches short or long; leaf and bract apices acute, sharply mucronate. Spikes cylindric and slightly torulose, 2-10 cm, with 5-25 fertile segments; bracts almost obscuring cymes. Fertile segments 4-5 × 4.5-6.2 mm, wider than long, widest distally, margins ca. 0.5 mm wide, scarious. Central flower semicircular distally, 2.2-2.8 × 2-2.8 mm, about as long as wide, usually reaching top of segment, only slightly larger than lateral flowers; anthers exserted, dehiscing after exsertion. 2n = 36.
"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."