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

Carex aquatilis Wahlenb.
water sedge (northern sedge)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Ewan Anderson  Email the photographer   (Photo ID #14358)

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Distribution of Carex aquatilis
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Species Information

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Perennial, tufted herb from long, creeping rhizomes; stems triangular, with smooth edges, 15-120 cm tall, equalling the leaves.
Sheaths tight, short; blades flat, well distributed along the stem, 3-7 mm wide, the lower ones slightly reduced.
The terminal spikes 1 to 3, short-stalked, with male flowers, the lower spikes 2 to 7, with female flowers, unstalked or with short stalks, 3-14 cm long, erect; bracts subtending the spikes leaflike, sheathless, the lower ones longer than the inflorescence, the upper ones reduced.
Perigynia egg-shaped, 2-3.6 mm long, 1.3-2.3 mm wide, brownish-green, 3-angled, the angles rounded, smooth to somewhat wrinkled, 2-nerved, the beaks entire; female scales egg-shaped, shorter than or about as long as the perigynia, often shortly awn-tipped, brownish-red to blackish, with lighter 3-nerved centres, with translucent margins; stigmas 2; achenes lens-shaped, granular, 1.4-1.8 mm long. Two subspecies may be recognized in BC 1. Male spikes 2 to 3; plants generally more than 20 cm tall; plants more common southward ssp. aquatilis 1. Male spike 1; plants generally less than 20 cm tall; plants more common northward ssp. stans (Drej.) Hult.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

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

Habitat / Range

Wet meadows, fens, streambanks and lakeshores in all vegetation zones; common throughout BC, less frequent along the coast; circumpolar, N to AK, YT and NT, E to NF and S to MA, VA, IN, MO, KA, NM, AZ and CA; Greenland, Eurasia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Carex aquatilis

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) 7 1105 2117
Slope Gradient (%) 0 0 40
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 286 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 6 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: BAFA(6), BWBS(133), CDF(1), CWH(23), ESSF(268), ICH(177), IDF(172), MH(9), MS(138), PP(1), SBPS(95), SBS(305), SWB(38)


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.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References