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

Carex unilateralis Mack.
one-sided sedge (lateral sedge)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #9516)

E-Flora BC Static Map
Distribution of Carex unilateralis
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Species Information

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Perennial, tufted herb from fibrous roots; stems 20-80 cm tall, exceeding the leaves.
Sheaths tight; blades flat, 2-4 mm wide, borne on the lower 1/3 of the stem.
Spikes 5 to 15, aggregated into a 1-3 cm long head, unstalked, with both female and male flowers, the female ones towards the tips; bracts subtending the spikes sheathless, the lower one much prolonged and 5-25 cm long, the others reduced and shorter.
Perigynia lanceolate or narrowly egg-shaped, 4-5 mm long, 1.5-1.8 mm wide, light green to straw-coloured or brownish, more or less flattened, the margins winged nearly to the bases and the upper 1/2 fringed with teeth, lightly several-nerved on both sides or nerveless below, the beaks shallowly bidentate, less than 1 mm long, narrowly margined and toothed below; female scales egg-shaped, brownish with green centres and translucent margins, somewhat shorter and narrower than the perigynia, short-awned; stigmas 2; achenes lens-shaped, 1.6-2 mm long.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist to wet sites in the lowland and montane zones; infrequent in S BC; S to ID and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Carex unilateralis

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) 1600 1600 1600
Slope Gradient (%) 24 24 24
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
60 59 60
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 4 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: BAFA(1)


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

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General References