Northern Prairie Wildlife Research Center
Woolgrass (Scirpus cyperinus)
- Family: Sedge (Cyperaceae)
- Flowering: July-October.
- Field Marks: Three or more bracts subtend the inflorescence. The spikelets are up to 1/4 inch long and become woolly at maturity because of the elongated bristles.
- Habitat: Swamps, sloughs, around lakes, wet woods.
- Habit: Robust perennial herbs with rhizomes.
- Stems: Erect, smooth, up to 5 feet tall.
- Leaves: Flat, elongated, smooth, mostly crowded near base of plant, up to 1/2 inch wide.
- Flowers: One per scale, with several scales per spikelet, the spikelets up to 1/4 inch long, forming large terminal clusters subtended by 3-6 leaf-like bracts.
- Scales: Narrowly lanceolate, pointed.
- Sepals: 0.
- Petals: 0.
- Stamens: 3.
- Pistils: 1; styles 3; ovary superior, subtended by 6 bristles.
- Fruits: Achenes elongated, less than 1/16 inch long, surpassed by long red-brown bristles at maturity.
- Notes: The achenes are eaten by waterfowl.
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