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

Carex filifolia Nutt.
thread-leaved sedge (threadleaf sedge)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Ryan Batten  Email the photographer   (Photo ID #66985)

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Distribution of Carex filifolia
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Carex filifolia var. filifolia

Species Information

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Perennial, densely tufted herb from stout, fibrous roots; stems 8-30 cm tall, longer than the leaves.
Sheaths tight, the old basal ones persistent and conspicuous, lined, breaking into threads; blades 2 or 3 per stem, in-rolled, borne near the base, about 0.25 mm wide, the lower ones persistent.
Spikes solitary, linear at first, expanding below at maturity, with both female and male flowers, the male flowers towards the tips, the female flowers below, 10-30 mm long, 3-6 mm wide, erect; bractless.
Perigynia egg-shaped, 3-4 mm long, 2-2.3 mm wide, dull whitish to straw-coloured, short hairy, at least above, obscurely 2-ribbed, unstalked, the beaks translucent, 0.2-0.4 mm long; female scales broadly egg-shaped, larger than and concealing the perigynia, rounded, greenish, the centres darker, the margins bright white-translucent; stigmas 3; achenes 3-angled, 2.2-3 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

Dry open sites in the steppe and montane zones; frequent in SC BC, less frequent eastward and northward; N to AK, YT and NT, E to SW MB and S to MN, KS, NM, AZ and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Carex filifolia

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) 353 1005 2550
Slope Gradient (%) 4 24 45
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
20 212 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
2 2 4
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: BG(7), IDF(8), IMA(3), PP(4)


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 elyniformis A.E. Porsild
Carex filifolia var. filifolia

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References