Burke: Cyperus difformis vs. Cyperus erythrorhizos

	Cyperus difformis	Cyperus erythrorhizos
		redroot flatsedge
Habit		Tufted annual, the triangular, solid, stout stems 1-7 dm. tall.
Leaves		Leaves grass-like, crowded near the base, the elongate blade 2-9 mm. wide, the sheaths closed.
Flowers		Inflorescence of clustered, cylindrical spikes, the terminal cluster sessile, the others on rays up to 7 cm. long, each spike 1-4 cm. long, with numerous, spirally arranged spikelets on an elongate rachis; scales of the spikelets in two vertical rows, 1.2-1.5 mm. long, with a green keel, closely set; perianth none; stamens 3; style trifid.
Fruits		Achenes unequally triangular, 0.7-1.0 mm. long, pale and shining.

	Cyperus difformis	Cyperus erythrorhizos
Flowering time		June-August
Habitat		Pond and lake shores, streambanks, seeps, vernal pools, and ditches at low to middle elevations.
Distribution	[WildflowerSearch map] [BONAP county map]	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. [WildflowerSearch map] [BONAP county map]
Origin		Native
Conservation status		Not of concern
Sibling taxa	C. acuminatus, C. bipartitus, C. diandrus, C. eragrostis, C. erythrorhizos, C. esculentus, C. fuscus, C. lupulinus, C. lupulinus × C. schweinitzii, C. schweinitzii, C. squarrosus, C. strigosus	C. acuminatus, C. bipartitus, C. diandrus, C. eragrostis, C. esculentus, C. fuscus, C. lupulinus, C. lupulinus × C. schweinitzii, C. schweinitzii, C. squarrosus, C. strigosus
Web links	Local floras: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Cyperus difformis

Cyperus erythrorhizos

redroot flatsedge

Habit

Tufted annual, the triangular, solid, stout stems 1-7 dm. tall.

Leaves

Leaves grass-like, crowded near the base, the elongate blade 2-9 mm. wide, the sheaths closed.

Flowers

Inflorescence of clustered, cylindrical spikes, the terminal cluster sessile, the others on rays up to 7 cm. long, each spike 1-4 cm. long, with numerous, spirally arranged spikelets on an elongate rachis;

scales of the spikelets in two vertical rows, 1.2-1.5 mm. long, with a green keel, closely set;

perianth none;

stamens 3;

style trifid.

Fruits

Achenes unequally triangular, 0.7-1.0 mm. long, pale and shining.

Cyperus difformis

Cyperus erythrorhizos

Flowering time

June-August

Habitat

Pond and lake shores, streambanks, seeps, vernal pools, and ditches at low to middle elevations.

Distribution

[WildflowerSearch map]

[BONAP county map]

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.

[WildflowerSearch map]

[BONAP county map]

Origin

Native

Conservation status

Not of concern

Sibling taxa