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

Carex mertensii Prescott ex Bong.
Mertens' sedge
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #89580)

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Distribution of Carex mertensii
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Species Information

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Perennial, tufted herb from short, stout rhizomes; stems 15-100 cm tall, exceeding the leaves.
Sheaths purplish-red towards the bases; blades flat, 2-6 mm wide, the lower ones much reduced.
Spikes 5 to 10, the terminal one with female flowers at the top and male flowers below, the lower spikes 4 to 9, with female flowers, long-stalked, 1-4 cm long, drooping; bracts subtending the spikes sheathless, leaflike, longer than the inflorescence.
Perigynia broadly egg-shaped, 3.5-4 mm long, 1.8-2.2 mm wide, papery thin, pale yellow to green or light brown, marginally 2-ribbed, otherwise faintly nerved, the beaks short, less than 0.4 mm long; female scales lanceolate, much shorter and narrower than the perigynia, pointed at the tips, reddish-black, with light brown margins; stigmas 3; achenes 3-angled, stalked, 1.2-1.5 mm long.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Late Spring
Fruit/Seed characteristics:
Colour: Brown
Present from Spring to Summer
Source:  The USDA

Habitat / Range

Roadsides, ditches, and wet meadows in the lowland and montane zones; common in BC south of 55degreeN, rare in NW BC; amphiberingian, N to AK and S YT, E to AB and S to ID, MT and CA; E Asia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Carex mertensii

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 0 664 2179
Slope Gradient (%) 0 19 105
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
6 188 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 5 8
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CWH(116), ESSF(40), ICH(22), MH(17), MS(2), SBPS(2), SBS(6)

Ecological Indicator Information

A shade-intolerant, montane to subalpine, Asian and Western North American sedge distributed more in the Pacific than the Cordilleran region. Occurs on fresh to very moist, nitrogen-rich soils within boreal, humid cool temperate, and cool mesothermal climates. Inhabits exposed mineral soil on high-elevation clearcuts, clearings, and waysides; often near streams or on seepage sites. A nitrophytic species characteristic of disturbed sites.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


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

Carex mertensii subsp. mertensii

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References