Description from Flora of China
Cladium ensigerum Hance, J. Bot. 23: 80. 1885.
Rhizomes horizontal, 4.5-6.8 mm thick. Culms flattened. Leaves basal; leaf blade ensiform, 3.8-50 × 0.7-2.5 cm, rigid, many veined, margin purple, finely scabrous, and denticulate. Inflorescences paniculate, narrow, usually 3-branched. Spikelets purple, ca. 11.3 × 3.5 mm, 2- or 3-flowered. Glumes ovate-lanceolate, apex acuminate. Nutlet subdrupaceous, ellipsoid, 3-furrowed; persistent style base thickened. Fl. and fr. Apr-Aug.
No specimen has been seen by the present authors.
● Swamps, lake margins. Hong Kong.