46. Cyperus iria Linnaeus, Sp. Pl. 1: 45. 1753.
碎米莎草 sui mi suo cao
Annuals. Roots fibrous. Culms tufted, 8-80 cm tall, slender to slightly stout, compressed triquetrous, base few leaved. Leaves much shorter than culm; sheath reddish brown to brownish purple; leaf blade 2-5 mm wide, slightly folded or flat. Involucral bracts 3-5, leaflike, lowermost 2 or 3 longer than inflorescence. Inflorescence a compound or rarely simple anthela; rays 4-9, mostly to 12 cm, each with 5-10 or more spikes. Spikes ovoid to oblong-ovoid, 1-4 cm, with 5-20 or more spikelets. Spikelets laxly arranged, ascending to slightly spreading, narrowly ovoid, very narrowly ovoid, or oblong, 4-10 × ca. 2 mm, compressed, 6-22-flowered; rachilla almost wingless, with successive glumes 0.7-0.9 mm apart. Glumes yellow to straw-colored, lax, broadly obovate, ca. 1.5 mm, membranous, 3-5-veined, keel middle abaxially green, margin apically white hyaline, apex retuse and mucronulate. Stamens 2(or 3); anthers ellipsoid; connective not prominent beyond anthers. Style very short; stigmas ± short. Nutlet dark brown, obovoid to subellipsoid, 1.2-1.4 mm, nearly as long as subtending glume, 3-sided, densely prominently puncticulate. Fl. and fr. Jun-Oct. 2n = 108, 112, 116, 128.
Forest margins, under shrubs or forests, grasslands by water, mountain slopes, along trails in valleys, river margins, wet places, paddy fields; below 100-2000 m. Anhui, Chongqing, Fujian, S Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, S Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, SE Xizang, Yunnan, Zhejiang [Afghanistan, Bangladesh, Bhutan, India, Indonesia, Japan, Kashmir, Korea, Laos, Malaysia, Myanmar, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Thailand, Turkmenistan, Uzbekistan, Vietnam; tropical Africa, SW Asia, Australia, Indian Ocean islands, Madagascar, Pacific islands].
Cyperus iria is naturalized in Central, North, and South America.