Northern Prairie Wildlife Research Center
Blunt Spikerush (Eleocharis obtusa)
- Family: Sedge (Cyperaceae)
- Flowering: June-October.
- Field Marks: The distinguishing features of this spikerush are the very blunt spikelets up to 1/2 inch long.
- Habitat: Roadside ditches, along streams and rivers, around ponds and lakes.
- Habit: Tufted annual from fibrous roots.
- Stems: Erect, smooth, unbranched, up to 18 inches long.
- Leaves: Reduced to sheaths.
- Flowers: One per scale, with several scales per spikelet, each spikelet ovoid to ellipsoid, rounded or slightly pointed at the tip, up to 1/2 inch long.
- Scales: Ovate to obovate, usually rounded at the tip, brown, 1/16-1/10 inch long.
- Sepals: 0.
- Petals: 0.
- Stamens: 3.
- Pistils: 1; styles 2 or 3; ovary superior.
- Fruits: Achenes yellow to brown, shiny, obovoid, about 1/20 inch long, capped by a small, flat tubercle, subtended by 6 barbed bristles.
- Notes: The achenes are eaten by waterfowl.
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