Japan Flora: Rhizomes stout, extensively creeping, covered with brown fi­brous remains of leaf-sheaths; culms stout, stiff, obtusely angled, nearly smooth, 10-20 cm. long; leaf-blades rather few, 4-6 mm. wide, coriaceous, light green, somewhat lustrous above, prom­inently scabrous on the margins; heads much-crowded, usually unisexual, ovoid to oblong-ovoid, 4-6 cm. long in the pistillate, nearly brae dess or with a few short bracts; spikes unisexual (rarely androgynous), the pistillate ovoid, about 15 mm. long; pistillate scales narrowly ovate, sulfur-yellow, with broad herbaceous margins, the broad many-nerved keel prolonged into a scabrous, awnlike mucro; perigynia longer chan or as long as the scales, coriaceous, appressed-erect, ovate, about 10 mm. long, planoconvex to somewhat concave-convex, rounded on the back, many-nerved, with a narrow irregularly serrate wing on the margins, the beak long, incurved, bifid at tip; achenes compressed-trigonous; stigmas 3. Apr.-June. Common on sand dunes along the seacoast.

w. Hokkaido, Honshu, Shikoku, Kyushu. Korea, Formosa, Ussuri, and Manchuria; introduced in e. N. America.