42. Cyperus malaccensis Lamarck, Tabl. Encycl. 1: 146. 1791.
茳芏 jiang du
Perennials. Rhizomes long, woody, rarely with thin stolons. Culms 0.5-1.5 m tall, 4-6 mm thick, acutely triquetrous, smooth, base brown and with a bladeless sheath, apical 1 or 2 sheaths with a blade. Leaf blade absent or to 3 cm × 4-8 mm, flat. Involucral bracts 3 or 4, leaflike, to 20 cm, longer to shorter than inflorescence. Inflorescence a simple or compound anthela; rays 6-10, mostly to 9 cm. Spikes broadly ovoid, with 5-10 spikelets; rachis strict, glabrous. Spikelets laxly arranged, linear, 0.8-2.5(-3) cm × ca. 1.5 mm, slightly turgid, spreading, 10-42-flowered; rachilla wings white, narrow, hyaline. Glumes reddish brown but margin yellowish to straw-colored, lax, oblong to elliptic, 2-2.5 mm, papery, inconspicuously 7-9-veined, margin involute at maturity, apex obtuse to rounded. Stamens 3; anthers linear; connective prominent beyond anthers. Style short; stigmas 3, slender. Nutlet blackish brown when mature, narrowly oblong, 1.7-2 mm, almost as long as subtending glume, 3-sided, minutely punctate. Fl. and fr. Jun-Nov.
River margins, ditch margins, water margins, shallow water, ocean beaches, salt marsh margins, forest margins, fields (usually cultivated); near sea level to 700 m. Fujian, Guangdong, Guangxi, Hainan, Jiangsu, Jiangxi, Sichuan, Taiwan, Zhejiang [India, Indonesia, Japan, Malaysia, Myanmar, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; SW Asia, N Australia].
The culms are used for making mats and hats.