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

Juncus ensifolius Wikstr.
dagger-leaf rush (swordleaf rush)
Juncaceae (Rush family)

Introduction to Vascular Plants

© Judith Holm  Email the photographer   (Photo ID #69039)

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Distribution of Juncus ensifolius
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Species Information

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Perennial herb from long rhizomes; stems erect, 30-60 cm tall.
Located on the lower half of the stem, strongly flattened, compressed laterally (iris-like), with partial cross-walls that run from the edges to about 2/3 of the leaf widths; sheaths open, with or without short, ear-shaped lobes.
Inflorescence terminal, with 1 to 10 heads, the heads globe-shaped, 5- to many-flowered; perianth segments greenish-brown to brownish-purple, 3-4 mm long, pointed, subequal; stamens 3 or 6; anthers 0.7-1 mm long, shorter than, or equal to the filaments.
Capsules, narrowly cylindrical, rounded, blunt, about as long as the perianth segments; seeds egg-shaped, about 0.5 mm long, lacking tail-like appendages.
This is a variable species and includes two varieties that are sometimes treated as distinct species:

1. Heads 2 to 5, purplish-brown; stamens 3; blades 3-6 mm wide, sheaths lacking ear-shaped lobes........................... var. ensifolius

1. Heads 5 or more, pale brown; stamens 6; blades 2-4 mm wide, sheaths with ear-shaped lobes............................. var. montanus (Engelm.) C.L. Hitchc.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: Brown
Present over the Summer
Source:  The USDA

Habitat / Range

Wet, open, sandy soil in marshes, peat bogs, lakeshores and margins of creeks and rivers, from the lowland and steppe to subalpine zones; frequent in BC south of 55degreeN, infrequent N; amphiberingian, N to AK and YT, E to SK and disjunct to ON and PQ, and S to CO, AZ and CA; E Asia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Juncus ensifolius

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) 5 531 1750
Slope Gradient (%) 0 5 75
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
5 192 315
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
3 6 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(2), CWH(73), ESSF(8), ICH(8), IDF(4), MH(4), MS(1), SBS(2)

Ecological Indicator Information

A very shade-intolerant, submontane to sub­alpine, Asian and Western North American rush (uncommon in the Central region). 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 ensifolius var. major Hook.
Juncus xiphioides var. triandrus Engelm.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References