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
slim spikerush
slender 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:

Alisma plantago-aquatica, Alopecurus aequalis, Eleocharis acicularis, Gnaphalium palustre, Limosella aquatica, Oenothera flava, Rorippa islandica, Rumex stenophyllus

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G4G5Q N2 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Eleocharis engelmannii 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:

10 – 40 cm

Roots:

fibrous

Culms:

caespitose, ascending, several, 0.5 – 1.5 mm wide

Leaves:

blade bearing leaves absent; bladeless sheaths, upper pale brown, 1-toothed

Inflorescence:

spikelet terminal, solitary, erect

Spikelets:

5 – 15 mm long, ovoid to cylindrical; proximal scale empty; floral scales 25 – 100, 8 – 12 per mm of rachilla, brownish to stramineus, midrib keeled, margin hyaline

Flowers:

perianth bristles 5 – 8 or absent, smaller than achene, brown; stamens 3, anthers brown to yellow; styles 2- or 3-cleft

Achenes:

1 – 2 mm long, broadly ovate, biconvex or < 1/3 trigonous, smooth, shining; tubercles depressed, covered top of achene, to 0.3 mm high

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 proximal scale always subtending a flower; culms to 1.5 mm wide	E. acicularis
1 Achenes without long rows of horizontal ridges; proximal scale subtending a flower or empty; culms to 5 mm wide	2

2 Tubercle conical, confluent with achene; stigmas 3	3
2 Large shrub; leaflets lobed, less than 3 cm long; fruits red and hairy	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 biconvex	5
4 Styles 3-fid; achenes trigonous	7

5 Tufted annuals, roots fibrous; achenes green, stramineus, or black; anthers 0.2 – 1 mm long	E. engelmannii
5 Perennials with rhizomes or stolons; achenes yellow to dark brown; anthers 1 – 2.5 mm long	6

6 Apex of distal leaf sheath with distinct tooth on all or some culms; base of spikelet with single empty scale nearly enclosing culm	E. erythropoda
6 Apex of distal leaf sheath without distinct tooth on all culms; 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 reticulate; tubercle broader than high; culms to 90 cm tall	E. elliptica
8 Achene surface minutely wrinkled or roughened but not reticulate; tubercle longer than broad; culms to 40 cm tall	9

9 Spikelets < 5 mm long; culms 4-angled and capillary	E. nitida
9 Spikelets to greater than 1 cm long; culms flat and wiry	E. compressa