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

Juncus stygius L.
bog rush (moor rush)
Juncaceae (Rush family)

Introduction to Vascular Plants

© Ryan Batten  Email the photographer   (Photo ID #66914)

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Distribution of Juncus stygius
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Juncus stygius var. americanus

Species Information

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Perennial, loosely tufted herb; stems erect, 10-25 cm tall.
Located on the lower part of the stem, nearly circular in cross-section, tapered, lacking cross-walls.
Inflorescence of 1 to 3, terminal heads of 2 to 5 flowers, the flowers lacking involucral bractlets; perianth segments green or light brown with wide translucent margins, 3.5-4.5 mm long, egg-shaped, subequal, blunt; stamens 6; anthers 0.4-0.7 mm long, shorter than the filaments; bracts leaflike, usually slightly longer than the inflorescence.
Capsules, blunt, 1.5 times longer than the perianth segments, pale brown to straw-coloured, 5-6 mm long; seeds spindle-shaped, about 1.2-1.4 mm long, with tail-like appendages at each end.
Plants from N America and E Asia have sometimes been separated into var. americanus. The taxonomic status of this variety is doubtful.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Pond margins and peat bogs in the lowland and montane zones; rare in coastal BC north of 50degreeN and in EC BC; circumpolar, N to AK, YT and NT, E to NF and S to ME, MI, WI and MN; Eurasia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Juncus stygius

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) 780 780 780
Slope Gradient (%) 0 0 0
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
8 8 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: SBS(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.

Synonyms and Alternate Names

Juncus stygius subsp. americanus (Buchenau) Hultén

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References