3 genera
17 species, 2 subspecies and varieties
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Cyperus acuminatussharp-pointed flatsedge, taper-tip flatsedge
Origin: Native
Cyperus bipartitusshining flatsedge
Distribution: Occurring on both sides of the Cascades crest in Washington; widespread in North America.
Habitat: Streambanks and other wet places in the valleys and lowlands; tolerant of alkali.
Origin: Native
Flowers: June-August
Cyperus diandrusumbrella flatsedge
Origin: Introduced
Cyperus eragrostistall flatsedge
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to California, also along the southern and eastern U.S. coast.
Habitat: Damp to wet shores, ditches, roadsides, and other disturbed areas at low elevations.
Origin: Introduced from South America
Flowers: June-August
Cyperus erythrorhizosredroot flatsedge
Distribution: Occurring on both sides of the Cascades crest in and in the Columbia River Gorge in Washington; southern British Columbia to California, east across much of North America to the Atlantic Coast.
Habitat: Pond and lake shores, streambanks, seeps, vernal pools, and ditches at low to middle elevations.
Origin: Native
Flowers: June-August
Cyperus esculentusyellow nut-grass
Distribution: Widely distributed throughout Washington; widespread throughout North America.
Habitat: Moist, low ground along streams and ditches, but sometimes in drier ground.
Origin: Native
Flowers: June-August
var. leptostachyus – yellow nutgrass
Cyperus fuscusbrown galingale
Origin: Introduced
Cyperus lupulinusGreat Plains flatsedge
Distribution: Great Plains to northeastern United States; occasional in the Pacific Northwest.
Habitat: Wet areas.
Origin: Native
Flowers: June - August
ssp. lupulinus – Great Plains flatsedge
Cyperus odoratusscented flatsedge
Origin: Introduced
Cyperus schweinitziisand flatsedge
Distribution: Occurring in scattered locations across Washington; Washington to Utah and Alberta, east across much of North America.
Habitat: Sandy lakeshores and riverbanks.
Origin: Native east Cascades, introduced in Seattle, WA
Flowers: July-September
Cyperus squarrosusawned flatsedge
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Atlantic Coast.
Habitat: Lake and pond shores, banks of slow moving streams and rivers, and other wet, open areas at low to middle elevations.
Origin: Native
Flowers: June-September
Cyperus strigosusfalse flatsedge, straw-colored flatsedge
Distribution: Widespread in the United States and adjacent Canada.
Habitat: Wet places, along the banks of large streams, in the valleys and lowlands.
Origin: Native
Flowers: July - September
Dulichium arundinaceumthree-way sedge
Distribution: Chiefly west of the Cascades in Washington, but also in Chelan, Yakima and Pend Oreille counties; British Columbia south to California, east to Idaho, Montana and to the eastern half of North America.
Habitat: Wet meadows, marshes, and shores of ponds and lakes.
Origin: Native
Flowers: July-September
Lipocarpha aristulatahalfchaff sedge
Distribution: Occurring along the Columbia River in central and south-central Washington; Washington to California and Arizona, east in Great Plains and central U.S.
Habitat: sandy soils of shorelines, stream banks, ponds, and ditches.
Origin: Native
Flowers: June-August
Lipocarpha micranthasmall-flowered halfchaff sedge
Origin: Native
Flowers: June - September
Lipocarpha occidentaliswestern halfchaff sedge
Origin: Native
Flowers: June - September