Northern Prairie Wildlife Research Center


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Aquatic and Wetland Vascular Plants of the Northern Great Plains

62. Cyperaceae, the Sedge Family

11. Scirpus L. -- Bulrush

1. Scirpus acutus Muhl. ex Bigel. -- Hardstem bulrush

Tall, slender, scapose perennial, densely colonial from extensive, stout rhizomes; culms rather stout, terete, 1-2.5(3.5) m long, dark green and resistant to crushing when fresh, fading with drying. Leaves consisting of 3-5 basal sheaths, the upper ones with tapering blades to 25 cm long; principal involucral bract erect, appearing as a continuation of the culm, 1.5-10 cm long, eventually turning brown. Inflorescence a panicle of up to 60 spikelets, appearing lateral, compact to open, the branches rather stiff; spikelets in glomerules of 2-15 (mostly 3-7) on the pedicels, grayish-brown, 5-15 mm long, 3-5 mm thick; scales suffused and often spotted with brown or dark red, 2-3.5 mm long, scarious, especially the lower ones often puberulent on the back, acute to slightly cleft at the apex, usually mucronate, the mucro to 0.5 mm long, the margins often finely ciliate; perianth of 6 unequal bristles, usually shorter than the achene body; stamens 3, the flattened filaments often persistent; styles bifid, seldom trifid. Achenes light green to dull or dark brown, lenticular, unequally biconvex, the body 1.8-2.2 mm long, 1.2-1.9 mm wide, the style beak minute to 0.5 mm long. Jun--mid Aug. Usually emergent in shallow to deep water of marshes, ditches, ponds and lakes, especially where the water is brackish; common, often abundant; (N.S. to B.C., s to NC, TX and CA).

Scirpus acutus, inflorescence.

Map key

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Return to Family -- Cyperaceae - The Sedge Family
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Menlo Park, CA [caww54]