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

Juncus arcticus Willd.
arctic rush
Juncaceae (Rush family)

Introduction to Vascular Plants

© Adolf Ceska  Email the photographer   (Photo ID #11504)

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Distribution of Juncus arcticus
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Juncus arcticus ssp. alaskanus

Species Information

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Perennial herb from long, creeping rhizomes; stems arising singly, not in dense clusters, round, usually straight, smooth, wiry, erect, 15-60 cm tall.
Reduced to small sheaths at the base of the stem; sheaths shiny brown.
Inflorescence dense, with 3 to 12 dark-coloured flowers; branches 1-7 cm long, appearing as if on the side of the stem, located above the middle, in the upper third of the stem; perianth segments dark with translucent margins, red-brown, 4-5 mm long, the outer slightly longer than the inner ones, pointed, the inner segments blunt; stamens 6; anthers shorter than the filaments; involucral bract 2-20 cm long, cylindrical, resembling a continuation of the stem.
Capsules, with blunt tips, about equal to the perianth segments; seeds spindle-shaped, 0.8-1.1 mm long, lacking tail-like appendages.
The taxonomic relationship between this species and related J. balticus has not been clarified. Juncus arcticus is a variable species, with many infraspecific taxa described. The whole complex requires further study and more intensive collecting throughout our area. I am treating all of our plants as ssp. sitchensis with the exception of some plants from northern BC which belong to the rare ssp. alaskanus.

1. Involucral bract 10-20 cm long; inner perianth segments pointed, narrowly translucent-margined................ssp. sitchensis Engelm.

1. Involucral bract 2-5 cm long; inner perianth segments with short awns, broadly translucent-margined................. ssp. alaskanus Hult.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Tidal flats and lakeshores in the lowland and montane zones; ssp. alaskanus - rare in N and E BC; ssp. sitchensis - common in coastal BC; ssp. alaskanus - N to AK, YT and NT; ssp. sitchensis - amphiberingian, N to AK, E Asia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Juncus arcticus

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) 0 1001 2011
Slope Gradient (%) 0 7 45
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
10 227 359
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 5 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: BG(6), BWBS(4), CWH(16), ESSF(18), IDF(17), PP(6)


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 arcticus var. alaskanus (Hultén) S.L. Welsh
Juncus balticus var. alaskanus (Hultén) A.E. Porsild

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References