Japan Flora: Relatively robust, usually stemless annual or sometimes with an obconical caudex; leaves broadly linear, gradually attenuate to a rather obtuse apex, flat, 5-17 cm. long, 5-8 (-10) mm. wide, 9- to 17-nerved; peduncles numerous, usually 5-ribbed; heads hemi- sphaerical or obconical-globose, 4 mm. long, 4-6 mm. in diameter; involucral bracts 10-12, ovate-oblong, 2-2.5 mm. long, 1.5 mm. wide, rounded at apex, shorter than the disc flowers; receptacle glabrous; flowers numerous, 1.5-2 mm. long; floral bracts obovate, obtuse-tipped; staminate calyx obovate, spathelike, trilobed at tip, obtuse, glabrous; pistillate flowers with obovate, spathelike, trilobed calyx, nearly gla­brous inside, the petals 3, free, oblong-lanceolate, pilose in­side, glabrous at apex, the stigmas 3, slightly shorter than the style.  Wet places and paddy fields in lowlands; Hokkaido, Honshu, Shikoku, Kyushu; quite common. Korea, Man­churia, and e. Siberia.

f. perpusillum (Nakai) Satake. A dwarf form. 

var. nigrum Satake. Floral bracts and calyx dark brown, relatively small, otherwise al­most as in the typical variety. Honshu