Description from Flora of China
Scirpus polytrichoides Retzius, Observ. Bot. 4: 11. 1786.
Annuals or short-lived perennials. Rhizomes very short or absent, with many remnant fibers from old leaves. Culms densely tufted, 5-25 cm tall, slender, cylindric, smooth, striate, with fewer leaves at base. Leaves shorter than culm; sheath yellowish brown, short, glabrous; leaf blade nearly Juncus-like, ca. 1 mm in diam., smooth. Involucral bract (0 or)1, 5-12 mm, needlelike, basally broadened, margin membranous. Inflorescences with a single terminal spikelet, ellipsoid to oblong, 5-8 × 3-3.5 mm, 10- to many flowered, apex obtuse to rounded. Glumes densely spirally imbricate, pale white and translucent with short brown lines at middle, sometimes apically slightly yellowish brown laterally, oblong, ca. 3 mm, membranous, 1-veined, not keeled, apex rounded and without or with only a very short hard mucro. Stamens 3; anthers linear, short. Style long, slightly compressed, basally inflated, apical half ciliate; stigmas 2. Nutlet grayish black, obovoid, ca. 1 mm, biconvex, sparsely verruculose and with transversely oblong reticulation. Fl. and fr. Mar-Sep. 2n = 10.
Wet salty places by sea, paddy fields; near sea level. Fujian, Guangdong, Hainan, Taiwan [Bangladesh, India, Indonesia, Malaysia, Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; tropical Africa, Australia, Madagascar].