Description

Key Characters:

Growth Form: Perennials, forming mats, stolons slender.

Stems: Culms pale green, soft, spongy, filiform, 3–8 cm tall, ca. 0.3 mm in diameter.

Roots:

Leaves: Leaves simple. Leaves basal or nearly so, reduced to bladeless sheaths. Margins entire. Sheathing; sheaths pale, membranous, 0.5–2 cm long, fugacious. Stipules absent.

Flowers: Flowers in spikelets 5–12–flowered, greenish white, ovoid, 3–4 mm long, ca. 1 mm wide, acute; glumes greenish white or occasionally faintly tinged brown, lanceolate–ovate, 1.2–1.5 mm long, acute to subacute, the keel green. Flowers bisexual (perfect). Calyx of 4 bristles, nearly white, very slender, retrorsely spinulose, longer than the achene. Corolla (petals) absent. Ovary superior; styles base depressed-conical, minute; stigmas 3.

Fruit: Achenes yellow; narrowly obovoid; trigonous; 0.6–0.7 mm long; finely cancellate with several rows of horizontally oblong cells. Seeds 1; seed coat thin; free from pericarp; embryo basal; endosperm abundant.

Ploidy: 2n = 56; 58

Habitat: Naturalized in taro paddies; along streams; and in marshes;.

Elevation Range: 20–1,220 m.