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

Juncus effusus L.
common rush
Juncaceae (Rush family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #4188)

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Distribution of Juncus effusus
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Species Information

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Perennial, strongly tufted herb in large, dense clusters from compact rhizomes; stems smooth or finely lined with 30 to 60 longitudinal ridges, 30-120 cm tall.
Reduced to short sheaths at the base of the stem.
Inflorescence with numerous flowers and branches, 3-12 cm long, appearing as if on the side of the stem; perianth segments green or light brown, 3-6 mm long, pointed, subequal; stamens 3; anthers about as long as the filaments; involucral bract 5-25 cm long, cylindrical, resembling a continuation of the stem, smooth or finely lined with 30 to 60 longitudinal ridges.
Capsules, egg-shaped, rounded on the tops, slightly shorter than the perianth segments; seeds ellipsoid, 0.5 mm long, lacking tail-like appendages.
Variable species with several varieties recognized in our area

1. Perianth segments greenish with little or no brownish borders, stiff when dry...................... var. pacificus Fern. & Wieg.

1. Perianth segments deep brown with green midribs, soft when dry.

2. Uppermost sheaths closed, leathery, lustrous, and chestnut brown throughout........................ var. gracilis Hook.

2. Uppermost sheaths looser, membranaceous, dull greenish-brown above............................ var. brunneus Engelm.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: Yellow
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Moist to wet disturbed places, pastures, fields, ditches, clearings, forest margins, marshes and peat bogs in the lowland, steppe, and montane zones; common W of the Coast-Cascade Mountains; N to AK and S to MT, ID, AZ and CA; Eurasia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Juncus effusus

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) 0 122 1805
Slope Gradient (%) 0 6 120
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 189 360
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: CDF(7), CWH(79), ESSF(1), ICH(2), SBS(2)

Ecological Indicator Information

A very shade-intolerant, submontane to subalpine, circumpolar rush (trans­continental in North America). Species occurs on very moist to wet, nitrogen-medium soils within subalpine boreal, temperate, and mesothermal climates. Common and often dominant in early-seral communities on water-receiving and water­collecting sites with exposed and compacted mineral soil and a fluctuating groundwater table. Frequently associated with Carex species Deschampsia caespitosa and Scirpus microcarpus. Characteristic of waterlogged sites.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


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 effusus var. subconglomeratus

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References