Japan Flora: Annual or sometimes a short-lived perennial; culms loosely tufted, 20-70 cm. long; leaves 2-8 mm. wide; corymbs rather large, simple or com­pound, 3-10 cm. long, with 3-5 rays to 10 cm. long, the bracts 3 or 4, leaflike, much exceeding the inflorescence; spikes ob- long-cylindric, very dense, with numerous spikelets; spikelets ascending to nearly erect, linear, compressed, 5-10 mm. long, 1.5 mm. wide, ferrugineous; scales narrowly oblong, slightly obtuse, somewhat acutely keeled; achenes half as long as the scale, narrowly oblong, 3-angled, slighdy compressed, grayish brown; stigmas 3. Swampy places; Honshu (Kanto and Yechigo Distr.) Korea, China, Amur, Northeast China, Ussuri, India, and Europe.