Scirpus divaricatus Elliott

The inflorescence of Scirpus divaricatus is very large and open. As in related species, the central spikelet of each cyme is sessile, and the others are long-pedicellate. The cymes often consist of only two spikelets in which the sessile, terminal spikelet may appear lateral.

Plants cespitose; rhizomes not apparent. Culms: fertile ones lax, reclining, inflorescences lopping over to (or nearly to) ground; nodes frequently with axillary bulblets. Leaves 10–18 per culm; proximal leaf sheaths green or brownish; proximal sheaths and blades with septa few, inconspicuous; blades 16–55 cm × 4–8 mm. Inflorescences terminal; rays divergent, proximal rays smooth, pedicels and distal rays scabrous, rays often bearing axillary bulblets; bases of involucral bracts green or brownish, not glutinous. Spikelets in open cymes, central spikelet of each cyme sessile, others long-pedicellate, spikelets cylindric to narrowly ovoid, 4–14 × 1–2 mm; scales light brown to reddish with broad green midribs, broadly ovate or elliptic, 1.2–1.8 mm, apex rounded to obtuse, apiculate, or sometimes short-mucronate, apiculus or mucro (if present) to 0.1 mm. Flowers: perianth bristles persistent, 6, stout, contorted, equaling or longer than achene, not projecting beyond it, with delicate, round-tipped, retrorse teeth in distal 1/2, enclosed within scales; styles 3-fid. Achenes off-white to yellowish brown, elliptic-obovate in outline, strongly trigonous with very strong angles and concave sides, 0.8–1 × 0.6–0.8 mm. 2n = 28.

Ala., Ark., Fla., Ga., La., Mo., N.C., S.C., Tenn., Tex., Va.

Fruiting late spring–early summer (May–Jun).

Lowland swamps along streams (often associated with Taxodium); 0–100m.

Scirpus divaricatus Ell. Bot. S.C. & Ga. 1: 88. 1816
Scirpus ambiguus Schultes in R. & S. Syst. Veg. Mant. 2: 85. 1824. Isolepis divaricata A. Dietr. Sp. PI. 2: 131. 1833.
Perennial; roots spongy; culms slender, erect, weak, 0.5-1.5 m. high, triangular, smooth; leaves to 3 dm. long, 4—10 mm. broad, deep green, soft, weakly scabrous on the margins and midrib, the sheaths green, the margin of the orifice broad, hyaline; involucral bracts 1 or 2, to 7 cm. long, leaflike, the involucels scale-like; inflorescence loose, often proliferous, the rays elongate, widely divergent, flexuous, the primary rays to 10 cm. long, smooth below, scabrous above, the secondary to 6 cm. long, scabrous, the tertiary to 3 cm. long, fourth and fifth branches often present; spikelets mostly pediceled, very slender, cylindric, at first 3-4 mm. long, 0.5-1 mm. broad, the axis elongating to 1 cm., 1-2 mm. thick; scales 1.5 mm. long, whitish or pale brown, blunt, incurved, with broad, green midrib and broad, hyaline margins; bristles 3-6, about equaling the achene; style trifid, reddish; anther ca. 1 mm. long; achene white or pale brown, smooth, sharply trigonous, ovoid, apiculate.
Type locality: "Between Bee's Creek and Purysburgh," South Carolina.
Distribution: Wet places; coastal states from Virginia south to Florida and west to Louisiana; Missouri.

Scirpus divaricatus là loài thực vật có hoa trong họ Cói. Loài này được Elliott miêu tả khoa học đầu tiên năm 1816.