Annual wetland herb, 7–17 cm high. Leaves ± terete to linear, erect to decumbent, (1.5–) 3–13.5 (–22) cm long, 0.5–2.0 mm diam.; basal sheath with fine acute auricles (0.4–) 1.4–2.6 (–3.9) mm long. Scape at fruiting erect to decumbent, 2.5–12 cm long, 0.5–1.7 mm diam. Infructescence an open spike, 1.5–9 cm long, 3–7 mm diam.; pedicels absent. Fruits (1–) 10–33 per infructescence, spaced along rachis, semi-erect to widespread, ellipsoid to obloid (sometimes basally spurred), 1.5–5.2 mm long, 0.7–1.2 mm diam. (excluding receptacle and spurs if present). Carpels 6, 3 fertile alternating with 3 sterile, united, not separating at maturity; mature fertile carpels with dorsal surface having a low narrow ridge within a shallow central longitudinal groove and very narrowly winged edges, the base of each wing a little rounded and widened in type form, extended into a downward to outward pointed spur 0.5–2.8 mm long in a spur-fruited form; wings of adjacent mature carpels well separated, slightly overlapping those of central axis; central axis conspicuous, 3-winged, gradually tapered at base into a receptacle to 1.1 mm long.
Occurs on the coastal plain in sand, loam or clay of winter-wet flats and swamps, or edging drainage lines and creeks; situations apparently saline to fresh.
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