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

Carex aperta Boott
Columbia sedge (Columbian sedge)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #60816)

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Distribution of Carex aperta
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Species Information

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Perennial, loosely or densely tufted herb from short rhizomes; stems triangular, with smooth edges, slightly rough below the inflorescence, 15-100 cm tall, exceeding the leaves.
Sheaths tight, short; blades flat, arising from the lower part of the stem, 2-6 mm wide, the lower ones slightly reduced.
The terminal spike or top 2 with male flowers, the lower 2 to 3 with female flowers and occasionally with a few male flowers at the top, unstalked or with short stalks, 1.5-4 cm long, erect; lowermost bract subtending the spikes leaflike, sheathless with brown ear-shaped lobes, usually shorter than or equalling the inflorescence, the upper ones reduced.
Perigynia egg- to globe-shaped, 2.5-2.8 mm long, 1.5-2 mm wide, green, inflated, nerveless, the beaks minute, up to 0.3 mm long; female scales egg-shaped, longer and narrower than the perigynia, purplish-brown, with lighter centres; stigmas 2; achenes lens-shaped, 1.3-1.7 mm long.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

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

Habitat / Range

Wet lake margins, riverbanks and meadows in the lowland, steppe and montane zones; frequent in S BC south of 55degreeN, infrequent in coastal BC, absent on the Queen Charlotte Islands and most of adjacent mainland; E to SW AB and S to MT, ID, and OR.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Carex aperta

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) 1630 1913 2200
Slope Gradient (%) 0 5 15
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
290 290 290
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
6 6 7
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: ESSF(3)


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 accedens T. Holm
Carex acutina var. tenuior L.H. Bailey
Carex stylosa var. virens L.H. Bailey
Carex turgidula L.H. Bailey

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References