Northern Prairie Wildlife Research Center
Slender Flatsedge (Cyperus rivularis)
- Family: Sedge (Cyperaceae)
- Flowering: July-October.
- Field Marks: This flatsedge differs by its 2 styles cleft only to about the middle and its reddish scales. The spikelets are less than 1/8 inch wide.
- Habitat: Sandy soil along rivers, wet meadows, along streams.
- Habit: Annual herb with fibrous roots.
- Stems: Tufted, erect, slender, unbranched, smooth, up to 15 inches long.
- Leaves: Mostly at the base of the plant, elongated, up to 1/10 inch broad.
- Flowers: One per scale, with several scales comprising a spikelet, each spikelet up to 3/4 inch long and up to 1/8 inch wide, reddish; the cluster of spikelets subtended by 3 leaflike bracts.
- Scales: Ovate, rounded at the tip, reddish.
- Sepals: 0.
- Petals: 0.
- Stamens: 2.
- Pistils: Styles 2-cleft to about the middle; ovary superior.
- Fruits: Achenes oblong, more or less flattened, dull, up to 1/10 inch long.
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