Cladium myrianthum Chun & F. C. How, Acta Phytotax. Sin. 7: 83. 1958.
Rhizomes short, stout. Culms to 2 m tall, 6-8 mm thick, flattened, several nodose. Leaves basal; leaf blade ensiform, ca. 1.5 m × 1.8-2.2 cm, smooth, margin entire, apically gradually narrowed. Inflorescences paniculate, consisting of a terminal and several lateral branches, 20-60 cm. Spikelets 2-4 clustered, oblong-ovoid, 4-5 mm, 2-4-flowered; basal 1 or 2 spikelets bearing nutlet. Glumes 5 or 6, brown, ovate to oblong, basalmost ca. 4 mm, pubescent, margins hyaline and ciliolate, apex obtuse. Perianth bristles 4-6, brown, shorter than style. Stamens 3; anthers oblong, 3.5-4 mm; connective apex apiculate. Style ca. 4 mm, persistent, with white hairs, base thickened; stigmas 3. Nutlet brown, obovoid, ca. 1 mm, acutely 3-sided, glabrous, apex beaked. Fl. and fr. Aug-Sep.
Riversides, forests, ditch sides; 900-2800 m. Hainan.