Japan Flora: Rhizomes short-creeping; culms tufted, 30-50 cm. long, soft, acutely angled, glabrous; leaf-blades thin and soft, flat，nearly glabrous, glaucous to bright green, rather abruptly narrowed toward apex, the basal sheaths bladeless; spikes 3 or 4, distant, the terminal staminate, the others pistillate, short-cylindric, very loosely several-flowered, spreading to pendulous, the bracts leaflike, long-sheathing; pistillate scales ovate, acuminate, pale, partially dark reddish or brownish; perigynia nearly as long as the scales, 5-6 mm. long, broadly ovoid-fusiform, glabrous, pale green, membranous, weakly nerved, rather long-beaked, with a truncate hyaline tip; stigmas 3. 

var. filipes. Leaf-blades 2-4 mm. wide, the sheaths dark reddish purple; staminate spike dark purplish brown or sometimes pale, linear, 10-15 mm. long, short- or rather long-peduncled, few-flowered, the pistillate loosely several-flowered, the upper contiguous, the lower dis­tant. Apr.-June. Woods or grassy places in hills and mountains; Honshu (n. distr., westw. to Kinki Distr.), Shi­koku; rather common.

var. tremula (Ohwi) Ohwi. Plant smaller; leaf-blades narrow, short, abruptly acuminate to acute; staminate spike broadly linear, very short, few-flowered, inconspicuous.  Apr.-May. Shikoku, Kyushu.

var. rouyana (Franch.) Kuek. Plant larger; leaf-blades 3-7 mm. wide, the sheaths pale or brownish, rarely partially purplish brown; staminate spike elongate, always long-peduncled and surpassing the adjacent one. Apr.-June. Woods in moun­tains and hills; Honshu (Kanto and westw. to Kinki Distr.).

var. arakiana (Ohwi) Ohwi.  Resembles the preceding variety, the leaves usually living two years, 8-12 mm. wide, deep green, the basal leaf-sheaths at least partially dark sanguineous-purple.  May. Honshu (Tango and Aki Prov.).