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

Introduction to Vascular Plants


© Ewan Anderson     (Photo ID #14358)


E-Flora BC Static Map

Distribution of Carex aquatilis
Click here to view the full interactive map and legend

Species Information

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.

SourceThe 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


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)
1105 7 2117
Slope Gradient (%)
0 0 40

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

286 0 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
6 0 8
Modal Nutrient Regime
# 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)

Habitat and 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.

SourceThe Illustrated Flora of British Columbia