Description from Flora of China
Herbs tufted. Leaf sheath keeled; leaf blade narrowly linear, laterally flattened, striate when dry, margin minutely papillose, apex acuminate. Peduncle terete to subterete. Spikes subglobose; basal bracts elliptic, papillose along apical 1/2 of midvein, apex emarginate; median bracts broadly elliptic, papillose on apical, deltoid part, veins 5--7, descendent, midvein dark brown, thick, margin membranous, apex spinulose. Lateral sepals curved, 4--6 × 1.4--2 mm, membranous, hyaline, keeled, base unequally tapering, apical margin usually serrulate, apex subacute to acute; median sepal hooded, ca. 2.5 mm, very thin, hy-aline, 1-veined, apex obtuse. Petal limb obovate, 3-veined. Stamens ca. 0.4 × 0.1 mm; inner anther locule longer than outer one; connective with membranous wing, apex obtuse. Staminodes 2-brachiate, ca. 4 mm. Ovary obovoid, 3-sided, ca. 2.5 mm in diam.
This species may be no more than a slightly smaller, insular form of Xyris pauciflora which it closely resembles.
* Emersed in marshes; near sea level to 100 m. N Taiwan.