Eleocharis elliptica Kunth
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Family: Cyperaceae
Genus: Eleocharis
Species Synonyms: Eleocharis tenuis var. borealis (Svens.) Gleason
Eleocharis capitata var. borealis Svens.
Common Names: slim spikerush
slender spikerush
elliptic spikerush
Canada: southern British Columbia – Alberta – Saskatchewan – Manitoba – Quebec – Newfoundland – Nova Scotia
Saskatchewan: southern Saskatchewan; Candle Lake – Carrot River – Welby
Ecoregion: Moist Mixed Grassland, Aspen Parkland, Boreal Transition, Mid-Boreal Upland
Saskatchewan: wet open or treed bogs and fens
Associated Species: grass of Parnassus, hairlike sedge, livid sedge, lobelia, marsh arrowgrass, mud sedge, northern green rush, seaside arrowgrass, sheathed sedge, small bedstraw, woollyfruit sedge
Provincial Status According
to Harms (2003):
Nature Conservancy Status:
G5 S2
Saskatchewan Species at
Risk Status:
Slim spikerush is threatened in Saskatchewan because it is rare or uncommon and most local populations are small. No immediate threats are known for this species.
Height: 5 – 90 cm
Roots: rhizomes evident, 0.5 – 2.5 mm thick; scales persistent, sometimes decaying to coarse fibres, membranous to papery
Stems: perennial, mat-forming, to 3 times as wide as thick, nearly round, sometimes compressed, 5 – 10-ridged
Leaves: blade bearing leaves absent; lower sheaths persistent, dark red near top, green to straw-coloured or red near base, papery to membranous, tip reddish-brown, occasionally toothed
Inflorescence: spikelet terminal, solitary, erect
Spikelets: 3 – 8 mm long, ovoid; floral scales 10 – 30, spreading in fruit, 5 – 7 per mm of spikelet axis, apex rounded to obtuse, medium to very dark brown, midrib pale
Flowers: perfect; perianth absent or rarely 1 – 3, up to half as long as achene, pale, with small spines; stamens 3, anthers orange-brown; styles 3-cleft
Achenes: persistent after scales fall off, three-angled, may be compressed, lemon yellow, orange or medium brown, rarely greenish, honeycombed; swelling at base of style short, brown to whitish, greatly depressed
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