Northern Prairie Wildlife Research Center


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Aquatic and Wetland Vascular Plants of the Northern Great Plains

62. Cyperaceae, the Sedge Family

6. Eriophorum L. -- Cottonsedge

3. Eriophorum polystachion L. -- Narrowleaf cottonsedge

Culms mostly solitary, weakly trigonous, becoming conspicuously so below the inflorescence, finely ridged, 3-6(9) dm tall, 1.5-3 mm thick. Leaves few to several, the uppermost arising in the upper 1/2 of the stem; blades flat or conduplicate, 3-6 mm wide when flat, commonly dying back from the tips; sheaths sometimes reddish, dark-girdled at the summit. Spikelets 2-8, roughly obconic, 1-3 cm in diameter with the bristles fully expanded; pedicels rather lax, the spikelets drooping; involucral bracts foliaceous, the principal one rather erect and usually surpassing the inflorescence; scales pale throughout or darkened with a pale tip and margins, ovate to lance-subulate, 4-6 mm long, deciduous, the midvein fading before reaching the very thin tip of the scale; perianth bristles white to faintly tawny, sometimes rather short when the achenes fail to develop. Achenes dark brown to nearly black, blunt at the tip, 2-3 mm long, ca. 1 mm wide. Jun--Jul. Bogs, fens, fresh wet meadows and springs; occasional from e MT and n ND to e SD; also the Black Hills and the Sand Hills; (Circumboreal, in N.Amer. s to ME, NY, MI, n NE, CO, n NM, ID and OR). E. angustifolium Honck.

Eriophorum polystachion, inflorescence and closeup of scale enclosing a flower. Perianth bristles normally hide the scales.

Previous Section -- Eriophorum gracile Koch -- Slender cottonsedge
Return to Family -- Cyperaceae - The Sedge Family
Next Section -- Eriophorum viridicarinatum (Engelm.) Fern.

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