Description from Flora of China
Pharus aristatus Retzius, Observ. Bot. 5: 23. 1789; Pota-mochloa aristata (Retzius) Griffith ex Steudel; Zizania aristata (Retzius) Kunth.
Culms floating, 0.5–1.5 m long. Leaf blades 3–7 × 0.5–2.5 cm, adaxial surface papillate, base rounded to cordate, abruptly constricted to a ca. 1 mm petiole-like base at junction with sheath, apex obtuse; ligule truncate, 0.5–0.8 mm. Inflorescence triangular in outline; branches short, lowermost subverticillate, reflexing at maturity. Spikelets greenish; stipe 3–6 mm; lemma body 7.5–8 mm, hispidulous on back, spinulose on veins; awn 1–1.4 cm; palea keeled and spinulose along midvein, outer veins smooth, apex acute. Anthers ca. 3.5 mm.
An aquatic grass forming extensive floating mats in ponds and lakes, often in shade of trees. Fujian, Guangdong, Hainan, Taiwan, Yunnan [Bangladesh, Cambodia, India, Laos, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand, Vietnam].