Japan Flora: Rhizomes sometimes elon­gate; culms soft, acutely 3-angled, 40-80 cm. tall, 2.5-4 mm. thick, smooth, the uppermost sheath 5-10 cm. long, partially reddish brown; spikelets 2-3 cm. long, 3-4 mm. thick, cylin- dric, rather acute, glaucous-green; scales appressed, broadly ovate, 4-5 mm. long, very obtuse; achenes broadly obovate, 1.5- 2 mm. long, light yellow, lustrous, biconvex, the brisdes 6, retrorsely scabrous, slighdy exceeding the style base; stigmas 3.  Shallow water on edge of ponds.

Honshu (Kii Prov.), Kyushu; rare. Ryukyus, Formosa, China, India, and Aus­tralia.