Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.

Habitat: Pond margins, marshes and ditches at low elevations.

Flowers: June-July

Origin: Native

Growth Duration: Annual

Conservation Status: Not of concern

Pollination: Wind

Robust annuals, scabrous but otherwise glabrous, the culms to 1 m. tall, hollow, erect, often stoloniferous.

Sheaths open; ligules 6-11 mm. long, acuminate, pubescent, usually lacerate; blades 5-10 mm. broad, flat.

Inflorescence narrow, congested, up to 3 dm. long, of racemose spikes; spikes 1-2 cm. long; spikelets 1-flowered, articulate below the glumes; glumes about 3 mm. long, subequal, strongly compressed and inflated, 3-nerved, semicircular, acute; lemmas equaling the glumes but much narrower; paleas slightly shorter than the lemmas, 2-nerved; stamens 3; lodicules 2, 1 mm. long.

Caryopsis.