Plants probably perennial, tufted, not stoloniferous; rhizomes present, ± horizontal, 0.2–0.4 mm thick, firm, longer internodes 3–7 mm, scales translucent or not. Culms often ascending, often spotted or streaked red-brown, cross section quadrangular or broadly elliptic, often sulcate, 1.5–8(–25) cm × 0.1–0.3 mm, soft. Leaves: distal leaf sheaths persistent or fugaceous, closely sheathing, not conspicuously wrinkled, colorless or pale brown, sometimes spotted red-brown, delicately membranous, apex narrowly acute. Spikelets: basal spikelets absent; never proliferous, ovoid or ellipsoid, laterally compressed or terete, 1.5–3.7 × 0.8–3 mm, apex acute; proximal scale empty, persistent, amplexicaulous, similar to floral scales; subproximal scale with a flower; floral scales distichous (spirodistichous), 8–22, 6–10 per mm of rachilla, colorless or pale brown, mottled red-brown to purple, ovate, (1–)2 × 1 mm, membranous, midribs green and red-brown, prominent, apex rounded to obtuse. Flowers: perianth bristles present or absent, (1–)4, colorless to white, vestigial to shorter than achene, 0–0.55 mm; spinules not evident at 45X; stamens (1–)3; anthers 0.35–0.45 mm; styles 2-fid (or 3-fid). Achenes whitish to pale brown, obovoid, biconvex, rarely trigonous, angles prominent, 0.5–0.8 × 0.4–0.6 mm, apex slightly constricted proximal to tubercle, smooth. Tubercles sessile, green or red-brown, pyramidal, birettaform or umbonate, 0.15–0.25 × 0.3–0.4 mm.

Fruiting summer–late fall. Moist banks, freshwater, damp pine barrens; of conservation concern; 0–50 m; Fla., Ga., Miss.; West Indies; Central America (Nicaragua).

The culms of Eleocharis bicolor sometimes have complete transverse septa which are prominent when plants are aquatic.