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

Schoenoplectus subterminalis (Torr.) Soják
water clubrush (swaying bulrush)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #85507)

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Distribution of Schoenoplectus subterminalis
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Species Information

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Perennial, usually aquatic herb from long, often reddish, weak, very soft rhizomes; stems practically circular in cross-section, tapered, flaccid, usually floating near the tips rather than emersed, 20-80 cm long.
Leaves 5 to 20 or more, borne near the base, usually floating, or rarely with erect or emergent leaves, about equalling the stems; sheaths straw-coloured to whitish, often free from the stems and resembling blades; blades elongate, slender, flaccid, C-shaped in cross-section near the base, flattened most of the length, mostly longer than the sheaths.
Spikes solitary, rarely 2, light brown, 7-12 mm long, egg-shaped to nearly cylindrical; involucral bracts solitary, conspicuous, stiff, not leaflike, appearing like an extension of the stem, (1) 1.5-6 cm long.
Scales 4-6 mm long, faintly-nerved, smooth, sometimes fringed with small, short hairs near the tips (at 40 times magnification), egg-shaped to lanceolate, pointed, the midribs firm, sometimes minutely exerted into awns up to 0.1 mm long; perianth bristles 4 to 6, brown, minutely- and finely-barbed backwards, shorter than to occasionally equalling or slightly surpassing the achenes; achenes 3-angled, brown, 2.5-3.8 mm long including the prominent (0.5 mm long), abruptly sharp-pointed tips.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Shallow ponds and streams in the lowland zone; infrequent in coastal and SC BC; N to AK, disjunct E to NF and S to ME, PA, SC, TN, MO, WY, ID and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Schoenoplectus subterminalis

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)
Slope Gradient (%)
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
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(4), CWH(10)


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 cool temperate & cool mesothermal.

Synonyms and Alternate Names

Scirpus subterminalis Torr.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References