Herbs, perennial, densely cespitose, (15–)20–30(–40) cm, base not abruptly bulbous. Stems compact. Leaves erect or ascending, 4–15 cm; sheaths glossy brown or red-brown, chaffy; blade green, filiform or narrowly linear, twisted, to 1 mm wide, smooth. Inflorescences: scape sheaths exceeded by leaves; scapes linear, nearly terete, 0.5(–0.7) mm wide, smooth, not ribbed; spikes ellipsoid to obovoid, 5–7(–10) mm; fertile bracts ca. 4.5 mm, margins nearly entire, apex rounded. Flowers: lateral sepals included, reddish brown, linear-curvate, 4 mm, keel firm, ciliate; petals unfolding in morning, blade obovate, 4 mm; staminodes bearded. Seeds translucent, ellipsoid, 0.5 mm, distinctly longitudinally ribbed, with fainter transverse lines. 2n = 18.
Phenology: Flowering summer–fall.
Habitat: Sphagnous bogs, low pine savanna, shores of dolines, coastal plain
Elevation: 0–100 m
Xyris isoetifolia, locally abundant only in northwest Florida, is most often mistaken for X. baldwiniana but is distinguishable by its bearded staminodes and more distinctly ribbed, shorter seeds.