Herbs, perennial, cespitose, 50–150 cm. Stems compact. Leaves ascending in narrow fans, (19–)30–50(–60) cm; sheaths pinkish or pale red, soft, smooth; blade pale green proximally, distally deep lustrous green, linear, flattened, plane, 5–15 mm wide, margins smooth. Inflorescences: scape sheaths exceeded by leaves; scapes linear, straight, distally slightly compressed, 1–2 mm wide, smooth, 2-ribbed; spikes ovoid to ellipsoid or cylindric, 10–20(–25) mm, apex usually blunt; fertile bracts 5–8 mm, margins entire, apex rounded. Flowers: lateral sepals slightly to conspicuously exserted, slightly curved, 6–8 mm, keel scarious, apex not red, broad, thin, lacerate; petals unfolding in afternoon, blade obovate, 5–6 mm; staminodes bearded. Seeds translucent, narrowly ellipsoid to ovoid, (0.6–)0.7(–0.8 mm), irregularly ridged and cross-ridged. 2n = 18.
Phenology: Flowering summer–fall.
Habitat: Sandy or peaty shallows and shores of ponds and sluggish acidic streams
Elevation: 0–100 m
Ala., Conn., Del., Fla., Ga., La., Maine, Md., Mass., Miss., N.H., N.J., N.Y., N.C., R.I., S.C., Tex., West Indies (Cuba), Mexico (Tabasco), West Indies (Cuba), Central America (Belize, Honduras, Nicaragua).
Although no specimens were seen for Virginia, Xyris smalliana is to be expected there.