E-Flora BC: Electronic Atlas of the Flora of British Columbia

Cyperus erythrorhizos Muhl.
red-rooted cyperus (redroot flatsedge)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Brenda Costanzo  Email the photographer   (Photo ID #22450)

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Distribution of Cyperus erythrorhizos
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Species Information

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Annual, tufted herb from fibrous roots; stems stout, mostly 5-70 cm tall.
Clustered towards the bases; blades well-developed, mostly 2-9 mm wide, elongate, about as long as the stem.
Inflorescence of dense, more or less elongate, head-like clusters, the terminal clusters unstalked, the others on rays up to 7 cm long (or some rays bearing only single spikes), each cluster with numerous, crowded, spirally arranged, cylindrical spikes on the elongate axis of the inflorescence, the spikes 1-4 cm long, the spikelets 6- to many-flowered, 3-12 mm long, 1-1.5 mm wide, slender, horizontally spreading; involucral bracts several, elongate, unequal, sometimes a little wider than the leaves, much surpassing the inflorescence.
Scales obscurely nerved, egg-shaped, closely set, the tips surpassing the ones below them by 0.4-0.7 mm, not recurved, the margins narrow, golden brown, the keels prominent, excurrent, green, 1.2-1.5 mm long; rachillas narrowly translucent-winged, persistent, but the scales eventually falling from them and the wings readily deciduous in short segments at maturity; stamens 3; achenes unequally 3-angled, pale, shining, 0.7-1 mm long.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Mid Summer
Fruit/Seed characteristics:
Colour: White
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Moist to wet lakeshores in the steppe zone; rare in SC BC; disjunct E to S ON and S to FL, MS, TX, NM, AZ and CA.

Source: The Illustrated Flora of British Columbia


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Cyperus halei Torr. ex Britton

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References