Fimbristylis acuminata Vahl

Glabrous perennial with very short rhizome. Stems slender, erect, densely tufted, obtusely 3-4-angled, sulcate, smooth, 5-30 cm by ½-1 mm. Leaves reduced to obliquely truncate, bladeless (or in the uppermost short-bladed) sheaths. Inflorescence con-sisting of a single terminal spikelet. Spikelet erect or slightly oblique, ebracteate, ovoid or lanceolate, terete, acute, many-flowered, 6-12 by 2-3½ mm; rachilla narrowly winged. Glumes spiral, chartaceous, ovate, obtuse or acutish, scarcely mucronulate, slightly keeled, stramineous to brownish, with green, darker lineolate, 3-5(-7)-nerved keel, 3½-4½ by 2¼-4 mm. Stamens 2-3; anthers oblong-linear or linear, ¾-1¼ mm. Style flat, scarcely dilated at the base, ciliate in the upper half, 2-3½ by ¼-2/5 mm; stigmas 2, much shorter than the style. Nut biconvex, with obtuse edges, broadly obovate or orbicular, sometimes somewhat broader than long, with very short, broad stipe, not umbonulate, with 5-8 strong transverse wavy ridges, obscurely reticulate by the minute, not impressed, hexagonal epidermal cells, dirty stramineous or brownish, rarely dark brown, 1¼-¾ mm long and wide.

In open wet and muddy places: swamps, rice-fields, river-banks, at low altitudes, up to 350 m.