Seashore Paspalum

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.

Annuals; culm long creeping, stoloniferous, flowering culm 6-60 cm tall, nodes glabrous. Blade 2.5-15 cm long, 3-8 mm wide; sheath longer than internode, often keeled, margins membranaceous; ligule membranaceous, truncate, 0.5-1 mm long. Racemes usually 2, conjugate or closely approximate; rachis 1-2 mm wide, 3-angular, often zigzag. Spikelet solitary, imbricate, elliptic, 3.5-4 mm long; lower glume absent; upper glume and lower lemma equal, thin, weakly 5-veined; lower lemma often transversely undulate; upper lemma 2.5-3 mm long, slightly concave-convex, with a tuft of short hairs at apex; upper palea ca. 2/3 as long as upper lemma; anther ca. 1.5 mm long.

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.

Tropics and subtropics of the Old World. Taiwan, halophilous.

Sandy seashores, swamps, along the margins of slow-moving streams. Hainan, Hong Kong, Taiwan, Yunnan [tropics and subtropics throughout the world].

Digitaria vaginata (Swartz) Magnier ex Debeaux; Paspalum distichum subsp. vaginatum (Swartz) Maire; Paspalum distichum var. vaginatum (Swartz) Grisebach; Sanguinaria vaginata (Swartz) Bubani.