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

Juncus castaneus Sm.
chestnut rush
Juncaceae (Rush family)

Introduction to Vascular Plants

© Hans Roemer  Email the photographer   (Photo ID #22989)

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Distribution of Juncus castaneus
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Juncus castaneus ssp. castaneus

Species Information

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Perennial herb from long, creeping rhizomes or stolons; stems erect, 10-35 cm tall.
Located on the lower parts of the stem, flat, lacking cross-walls.
Inflorescence of 1 to 3, dark, long-stalked, terminal heads of 3 to 10 flowers; perianth segments chestnut-brown, 3.5-6.5 mm long, egg-shaped, the outer segments equal to the inner ones or slightly longer, pointed, the inner segments blunt; stamens 6; anthers 1-1.5 mm long, shorter than the filaments; lowest bracts leaflike, about as long as the inflorescence, the upper bracts awnlike and shorter than the flowers.
Capsules, pointed, 1.5 times longer than the perianth segments, dark chestnut brown; seeds spindle-shaped, about 0.9 mm long, with tail-like appendages at each end.
Two subspecies have been recognized in W North America. Juncus castaneus ssp. leucochlamys has not been reported from BC, but can be expected near the YT border:

1. Heads 1 to 3, dark, unstalked or short-stalked; lowest bract short................... ssp. Castaneus

1. Heads several, pale, long-stalked; lowest bract long................... ssp. leucochlamys (Zing. ex Krecz.) Hult.

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

Moist to wet gravel bars, bogs, fens, lakeshores and marshes in the montane and subalpine zones; frequent in BC north of 55degreeN, E of the Coast Mountains and in the Rocky Mountains; circumpolar, N to AK, YT and NT, E to NF and S to NM; Eurasia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Juncus castaneus

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) 820 1591 1951
Slope Gradient (%) 0 4 15
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
65 2 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
2 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: BAFA(10), ESSF(1), IDF(1), PP(1), SWB(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.

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