Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Carex lacustris Willd.
- Family: Sedge (Cyperaceae)
- Flowering: May-August
- Field Marks: This coarse sedge is distinguished by its 2-4 separate male spikes and
2-4 separate, short-stalked female spikes, and its many-nerved, beaked perigynia up to
1/3 inch long.
- Habitat: Swamps, shallow standing water.
- Habit: Coarse perennial herb from creeping rhizomes.
- Stems: Upright, stout, triangular, rough to the touch or sometimes smooth except near the
tip, up to 4 feet tall, usually purplish or reddish at base.
- Leaves: Elongated, glaucous, rough to the touch, up to 3/4 inch wide, longer than the
- Flowers: Borne in spikes, with 2-4 separate male spikes and 2-4 separate female spikes,
sometimes with a few male flowers toward the top; male spikes slender, brownish, up to
3 inches long; female spikes oblong-cylindrical, up to 4 inches long, up to 3/4 inch wide, all
but the lowest upright; female scales lanceolate, rounded or awned at the tip, as long as or
shorter than the perigynia.
- Sepals: 0.
- Petals: 0.
- Stamens: 3.
- Pistils: Borne in perigynia, the perigynia lance-ovoid, smooth, many-nerved, up to 1/3 inch
long, tapering to an outwardly curved, 2-toothed beak; styles 3.
- Fruits: Achenes triangular.
- Notes: The achenes are eaten by waterfowl.
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