Cyperus
cyperus, flatsedge
12 species
2 subspecies and varieties
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Cyperus acuminatussharp-pointed flatsedge, taper-tip flatsedge
Distribution: Occurring east of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to California, east across most of North America to the Atlantic Coast.
Habitat: Shores and vernal pools.
Origin: Native
Flowers: June-August
Growth Duration: Annual, Biennial, Perennial
Cyperus bipartitusshining cyperus, shining flatsedge
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California, east across most of the U.S. to eastern Canada and the Atlantic Coast.
Habitat: Streambanks and other wet places in the valleys and lowlands; tolerant of alkali.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Cyperus diandrusumbrella flatsedge
Distribution: Occurring east of the Cascades crest in southern Washington; native to central and eastern North America.
Habitat: Emergent shorelines in sandy, peaty, or slightly brackish areas (though seldom where disturbed).
Origin: Introduced from eastern and central North America
Flowers: June-August
Growth Duration: Annual
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
Growth Duration: Perennial
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
Growth Duration: Annual, Perennial
Cyperus esculentusyellow nut-grass
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Moist, low ground along streams and ditches, but sometimes in drier ground.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
var. leptostachyus – yellow nutgrass
Cyperus fuscusbrown flatsedge, brown galingale
Distribution: Occurring on both sides of the Cascades crest in Washington; southern Washington to California, east to Nevada; also in eastern North America.
Habitat: Damp, silty riverbanks.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Annual
Cyperus lupulinusGreat Plains flatsedge
Distribution: Occurring east of the Cascades crest in southeastern Washington; disjunct in southeastern Washington and adjacent Oregon and Idaho, otherwise from U.S. Great Plains to eastern Canada and Atlantic Coast.
Habitat: Cobble riverbanks and rocky canyon slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
ssp. lupulinus – Great Plains flatsedge
Cyperus schweinitziisand flatsedge
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to the Rocky Mountains, Great Plains, Great Lakes region, and northeastern North America.
Habitat: Sandy lakeshores and riverbanks.
Origin: Native east Cascades, introduced in Seattle, WA
Flowers: July-September
Growth Duration: Perennial
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
Growth Duration: Annual
Cyperus strigosusfalse flatsedge, straw-colored flatsedge
Distribution: Occurring chiefly east of the Cascades crest and along the Columbia River in Washington; Washington to California, east across most of North America to the Atlantic Coast.
Habitat: Wet places, along the banks of large streams, in the valleys and lowlands.
Origin: Native
Flowers: July-September
Growth Duration: Perennial