Eleocharis parvula (Roemer & J.A. Schultes) Link ex Bluff, Nees & Schauer
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Family: Cyperaceae
Genus: Eleocharis
Species Synonyms: Eleocharis parvula var. anachaeta (Torr.) Svens.
Eleocharis parvula var. coloradoensis (Britt.) Beetle
Eleocharis leptos (Steud.) Svens.
Eleocharis leptos var. coloradoensis (Britt.) Svens.
Eleocharis leptos var. johnstonii Svens.
Eleocharis membranacea Gilly
Eleocharis coloradoensis (Britt.) Gilly
Common Names: dwarf spikerush
dwarf spikesedge
little-head spikerush
small spikerush
Canada: southwestern Saskatchewan
Saskatchewan: southwestern Saskatchewan; Webb – Tessier
Ecoregion: Moist Mixed Grassland, Mixed Grassland
Saskatchewan: moist shores of saline lakes
Associated Species: cosmopolitan bulrush, dock, rayless alkali aster, salt-marsh spurry
Provincial Status According
to Harms (2003):
Nature Conservancy Status:
G5 N3 S1
Saskatchewan Species at
Risk Status:
Dwarf spikerush is threatened in Saskatchewan because it is extremely rare and is limited to one general region of the province. This species is usually locally numerous but within limited areas. Possible threats have been identified for this species. Dwarf spikerush has not been reported elsewhere in Canada and the Saskatchewan populations may represent a northern range extension.
Height: 2 – 7 cm
Roots: rhizome short, terminated by J- or U-shaped structures; enlarged structures at stem base 4 – 5 mm long, narrowly spindle-shaped, straight
Stems: perennial, mat-forming, thread-like, round in cross section
Leaves: blade bearing leaves absent; leaf sheaths short, membranous
Inflorescence: spikelet terminal, solitary, erect
Spikelets: 2 – 4 mm long, ovoid; floral scales 6 – 10 per spikelet, oval, lowest one empty, entirely straw-coloured or green to brown
Flowers: 2 – 9 per spikelet, perfect; perianth bristles 6 or absent, stout to slender, usually about same length as achene, straw-coloured; styles 3-cleft
Achenes: egg-shaped, thickly three-angled, angles distinct, straw-coloured or pale brown or black; swelling at base of style short
1 Achenes with 9 – 13 longitudinal rows of horizontal ridges between prominent longitudinal ridges and achene angles; spikelets with lowest scale always subtending a flower; stems to 1.5 mm wide
E. acicularis
1 Achenes without long rows of horizontal ridges; lowest scale subtending a flower or empty; stems to 5 mm wide
2 Swelling at tip of achene conical, confluent with achene; stigmas 3
2 Swelling at tip of achene well-differentiated; stigmas 2 or 3
3 Spikelets to 3 mm long, internodes equal in thickness and length throughout the spikelet; scales 5 – 500 per spikelet, green or pale brown; stems < 10 cm tall; rhizome lacking a bulb
E. parvula
3 Spikelets to 7 mm long, proximal internodes thicker and shorter than internodes in the middle of the spikelet; scales 4 – 12 per spikelet, tinged with purple or brown; stems to 40 cm tall; rhizomes bulbous
E. quinquefolia
4 Styles 2-fid; achenes convex
4 Styles 3-fid; achenes three-sided
5 Tufted annuals, roots fibrous; achenes green, straw-coloured, or black; anthers 0.2 – 1 mm long
E. engelmannii
5 Perennials with rhizomes or runners; achenes yellow to dark brown; anthers 1 – 2.5 mm long
6 Tip of uppermost leaf sheath with distinct tooth on all or some stems; base of spikelet with single empty scale nearly enclosing stem
E. erythropoda
6 Tip of distal leaf sheath without distinct tooth on all stems; base of spikelet with 2 or 3 firm, empty scales
E. palustris
7 Achenes biconvex (or < 1/3 of achenes trigonous); tufted annuals; spikelets never proliferous
E. engelmannii
7 Achenes trigonous; annuals or perennials, rhizomatous or stoloniferous; spikelets may be proliferous
8 Achene surface honey-comb netted; swelling at tip of achene broader than high; stems to 90 cm tall
E. elliptica
8 Achene surface minutely wrinkled or roughened but not netted; swelling at tip of achene longer than broad; stems to 40 cm tall
9 Spikelets < 5 mm long; stems 4-angled and capillary
E. nitida
9 Spikelets to greater than 1 cm long; stems flat and wiry
E. compressa