Species: Eleocharis engelmannii Steud.

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Eleocharis engelmannii Steud.

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TAXONOMY

Family:

Cyperaceae

Genus:

Eleocharis

Species Synonyms:

Eleocharis monticola Fern.
Eleocharis monticola var. pallida St. John
Eleocharis obtusa var. detonsa (Gray) Drapalik & Mohlenbrock
Eleocharis obtusa var. engelmannii (Steud.) Gilly
Eleocharis ovata var. engelmannii (Steud.) Britt.
Eleocharis engelmannii var. monticola (Fern.) Svens.
Eleocharis engelmannii var. robusta (Fern.

Common Names:

horned beakrush
slender spikerush
slim spikerush
elliptic spikerush

DISTRIBUTION

Canada:

southwestern Alberta – Saskatchewan – southern Manitoba, southern Ontario

Saskatchewan:

southern Saskatchewan; Saskatoon - Regina

Ecoregion:

Moist Mixed Grassland, Aspen Parkland

HABITAT

Saskatchewan:

shores, marshes, and drying slough bottoms

Associated Species:

American water plantain, awl-leaf mudwort, cudweed, narrowleaf dock, needleleaf spikerush, northern marsh yellowcress, yellow evening primrose

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G4G5Q N2 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Horned beakrush 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:

8 - 60 cm

Roots:

rhizome stout, firm, cortex persistent, scales decaying to fibres

Stems:

perennial, mat-forming, compressed, wiry, to 5 times as wide as thick, firm, 2 – 12-ribbed

Leaves:

blade bearing leaves absent; lower leaf sheaths persistent, reddish at top, green to reddish at bottom, papery

Inflorescence:

spikelet terminal, solitary, erect

Spikelets:

4 – 12 mm, ovoid; floral scales 20 – 60, 6 per mm of spikelet axis, spirally arranged, spreading in fruit, medium to dark brown, occasionally straw-coloured or colourless, apex tapered to a long or short point and hyaline and often toothed or jagged

Flowers:

perfect; perianth bristles 0 – 5, early deciduous, straw-coloured, shorter than to equaling achene, bearing small spines; stamens 3, anthers yellow to orange-brown; styles 3-fid

Achenes:

1 – 1.3 mm long, inversely egg-shaped, bluntly three-sided, yellowish-brown or dark brown; swelling at base of style short, brown to whitish

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