Japan Flora: Culms loosely tufted, stout, 80-120 cm. long; leaves 8-15 mm. wide; corymbs large, decompound, 10-30 cm. long and as broad, with 5-10 stiff rays to 20 cm. long, the bracts 4 or 5, leaflike, much longer than the corymb; spikes 10-15 mm. thick, cylindric, very dense with numerous spikelets; spikelets spreading, 5-10 mm. long, flattened, often yellowish brown in front; scales ovate, 1.7-2 mm. long, the keel green, ending in a recurved awnlike mucro; achenes half as long as the scale, elliptic, stramineous; stigmas 3. Sept-Oct. Swamps and shallow ponds in lowlands; Honshu (Hitachi and Tokyo). Korea, se. Asia.