Description from Flora of China
Panicum interruptum Willdenow, Sp. Pl., ed. 4, 1: 341. 1797; Hymenachne interrupta (Willdenow) Buse; Panicum inundatum Kunth, nom. illeg. superfl.; Sacciolepis simaoensis Y. Y. Qian.
Vigorous aquatic perennial. Culms rooting and floating in water, spongy, succulent, hollow, smooth, glabrous, 20–50 cm tall or more, up to 1 cm in diam. Leaf sheaths loose, papery; leaf blades linear, flat, soft, 4–12 × 0.3–0.6 cm, base abruptly rounded, apex acuminate; ligule truncate. Panicle spikelike, 10–30 cm. Spikelets light green, asymmetrically oblong, lightly dorsally compressed, 3.3–5 mm, glabrous, acute to subacute; lower glume broadly ovate, 1/4–1/3 spikelet length, 3–5-veined; upper glume ovate, slightly gibbous, 9-veined, acute; lower floret neuter or infrequently staminate, lemma as long as upper glume, ovate, 7-veined; lower palea present, often much reduced; upper lemma yellowish, narrowly ovate, 2/3–3/4 spikelet length, acute. Fl. and fr. Jun–Dec. 2n = 18.
Sacciolepis interrupta has a mainly Asian distribution. Sacciolepis africana C. E. Hubbard & Snowden is its counterpart in Africa, but has on average somewhat shorter (2.5–4 mm), more obtuse spikelets. However, the division between the two species is not clear-cut, and there is some overlap in individual characters.
Swamps, shallow water, rice fields. SW Yunnan [India, Indonesia, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam; Africa].