Description from Flora of China
Digitaria vaginata (Swartz) Magnier ex Debeaux; Paspalum distichum subsp. vaginatum (Swartz) Maire; Paspalum distichum var. vaginatum (Swartz) Grisebach; Sanguinaria vaginata (Swartz) Bubani.
Perennial with short rhizome and long stolons. Culms solitary or tufted, many-noded, 10–50 cm tall. Leaf sheaths imbricate, often keeled, margins membranous; leaf blades distichous, linear, rather stiffly ascending, 2.5–15 × 0.3–0.8 cm, apex acute; ligule 0.5–1 mm. Inflorescence of (1–)2(–3) racemes arising together at culm apex; racemes 2–5 cm, usually closely approximate when young, later spreading; spikelets single, in 2 rows; rachis 1–2 mm wide. Spikelets pale brownish green, narrowly lanceolate-oblong, strongly flattened, 3.5–4 mm, acute; lower glume absent or rarely a tiny vestige; upper glume thinly papery, weakly 5-veined, midvein often suppressed, glabrous; lower lemma resembling upper glume; upper lemma pale green, 2.5–3 mm, shorter than spikelet, cartilaginous, apex minutely pubescent. Fl. and fr. Jun–Sep.
This is one of the first plants to colonize the seashore. It is an efficient sand binder and a common saltmarsh plant, where it may form pure stands. It is sometimes also found in inland saline marshes.
Sandy seashores, swamps, along the margins of slow-moving streams. Hainan, Hong Kong, Taiwan, Yunnan [tropics and subtropics throughout the world].