Description from Flora of China
Annual. Culms erect, robust, 1–3 m tall, more than 10-noded, branched. Leaves cauline; leaf sheaths shorter than internodes, glabrous; leaf blades linear-lanceolate, usually glabrous, 10–40 × 1.5–7 cm, midvein stout, base subrounded or cordate, margins scabrous, apex acute; ligule 0.6–1.2 mm. Male raceme 1.5–4 cm, spikelets in pairs with terminal triad; utricle ovoid to cylindrical, usually bony, shiny, 7–11 × 6–10 mm, white, bluish or gray-brown, sometimes with apical beak. Male spikelets oblong-ovate, 6–9 mm; glumes many-veined, lower glume winged on keels, wings 0.4–0.8 mm wide, wing margin ciliolate; anthers 4–5 mm. Fl. and fr. Jun–Dec. 2n = 20.
This species is now widely cultivated in tropical and subtropical regions of the world (Job's Tears). There are many variants, of which the following are the most distinct.
Streams, marshy valleys, moist fields, by houses, often cultivated. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Yunnan, Zhejiang [Bhutan, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam].