Description from Flora of China
Cyperus sesquiflorus (Torrey) Mattfeld & Kükenthal var. cylindricus (Nees) Kükenthal; Kyllinga odorata Vahl subsp. cylindrica (Nees) T. Koyama; K. sesquiflora Torrey subsp. cylindrica (Nees) T. Koyama.
Perennials. Rhizomes short. Culms tufted, 8-32 cm tall, slightly slender, 3-angled, smooth, base few leaved. Leaves shorter than culm; sheath short; leaf blade 2.5-4 mm wide, flat, margin denticulate. Involucral bracts 3(or 4), ± horizontal, sometimes reflexed. Spikes (1-)3, congregate, with numerous densely arranged spikelets; middle spike oblong-cylindric to oblong, 6-14 × 4-6 mm; lateral spikes oblong, ca. 6 mm. Spikelets ovoid-ellipsoid to ovoid, ca. 2.2 mm, slightly turgid, 1- or 2-flowered. Glumes greenish yellow to yellowish white, broadly ovate, ca. 2 mm, concave, veins several, keel not spinulose, apex mucronate. Stamens 2; anthers broadly linear. Style of medium length; stigmas 2. Nutlet at first yellow but dark brown when mature, ellipsoid to obovoid-ellipsoid, compressed biconvex, with punctate processes. Fl. and fr. May-Jul.
Wet places along trails, river margins, ditch margins; near sea level to 2000 m. Fujian, Guangdong, NE Guizhou, SE Jiangxi, Taiwan, S Yunnan [Bhutan, India, Indonesia, Japan (Ryukyu Islands), Nepal, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; tropical Africa, Madagascar].