Species: Eleocharis elliptica Kunth

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Eleocharis elliptica Kunth

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TAXONOMY

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

DISTRIBUTION

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

HABITAT

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

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G5 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

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.

SPECIES DESCRIPTION

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

ELEOCHARIS KEY FOR SPECIES FOUND IN SASKATCHEWAN

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

2 Swelling at tip of achene conical, confluent with achene; stigmas 3	3
2 Swelling at tip of achene well-differentiated; stigmas 2 or 3	4

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	5
4 Styles 3-fid; achenes three-sided	7

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

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

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

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