The fertile leafy culms of this large sedge are 2½-4' tall. They are pale-medium green, glabrous, stout, and strongly 3-angled. The lower half of each culm is largely hidden by the leaves. The leaf blades are ¾-3' long and 8-20 mm. across. They are ascending, arching, or floppy; some blades can overtop the inflorescence of a fertile culm. Each leaf blade is grooved toward the middle and bent downward near its margins; as a result, the cross-section of a blade has a shallow M-shape. The upper blade surface is gray-green, blue-green, or pale-medium green, while the lower blade surface is whitish green and glaucous; both surfaces are glabrous. The leaf sheaths are pale-medium green on 2 sides and membranous on 1 side; they are glabrous. The ligules are much longer in length than they are across; they are short-membranous. Toward the bottom, the fertile culms have leaves with basal sheaths, but no blades (or poorly developed ones); they are often surrounded by the tan remnants of old basal sheaths. The bottom of the culms and their young basal sheaths are often reddish-purple. In addition to the fertile culms, there are also infertile culms that are very short (less than 1' long). These latter culms produce full-sized leaves, but no spikelets. They are usually more numerous than the fertile culms. Each fertile culm terminates in an inflorescence consisting of 2-4 pistillate (female) spikelets and 2-5 staminate (male) spikelets; an inflorescence is typically ¾-2' long. In each inflorescence, the pistillate spikelets are located below the staminate spikelets. Both types of spikelets are organized around a central stalk; they are ascending to erect and relatively straight. The female spikelets are 2-3½" long and cylindrical in shape (about 1.5 cm. across); the perigynia of these spikelets are packed densely together and they are slightly ascending to ascending. The female spikelets have short stiff peduncles up to 1" long or they are nearly sessile. The perigynia (sacs covering the achenes) are 5-7 mm. long and 1.5-2.5 mm. across; they are lanceoloid in shape and slightly flattened, tapering to a beak with a pair of short teeth at its apex. These teeth are about 0.5 mm. in length. Perigynia are glabrous and they have several longitudinal veins that are relatively conspicuous. Immature perigynia are light green, but they later become yellow and finally turn brown at maturity. The pistillate scales are shorter than the perigynia; they are lanceolate-ovate in shape, tapering to an acute tip that is often awned. The scales initially have green central veins and membranous margins; later they become brown or black. The staminate spikelets are 1½-3½" long and very narrow (about 5 mm. across); they soon turn brown. The uppermost staminate spikelet has a short peduncle up to 3" long, while the remaining staminate spikelets are sessile (or nearly so). At the bases of these spikelets are leafy bracts; the lowest bract is large and leafy in appearance, while the remaining bracts become progressively shorter and more narrow in size as they ascend the central stalk of the inflorescence. The blooming period is late spring to early summer (rarely later), lasting about 1-2 weeks. The florets of the spikelets are cross-pollinated by the wind. Afterwards, mature perigynia disarticulate from their spikelets; they are somewhat inflated and can be distributed to new areas by water, carrying their achenes with them. Each perigynium contains a single achene; the achenes are 2.0-2.5 mm. long, broadly ellipsoid in shape, bluntly 3-angled, and glabrous. The root system is fibrous and long-rhizomatous. This sedge often forms large clonal colonies of plants.
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