1. Scleria verticillata Muhlenberg ex Willdenow, Sp. Pl. 4(1): 317. 1805.
Plants annual; rhizomes absent; roots reddish, fibrous. Culms solitary or in tufts, erect, slender, (7–) 10–60 cm, glabrous. Leaves: sheaths green or streaked with purple, smooth or weakly ribbed, usually narrowly winged, long-villous; contra-ligules minute; blades linear or filiform, plane or keeled, shorter than culms, 0.5–2 mm wide, glabrous. Inflorescences terminal, glomerate-spicate, 2.5–13 cm; glomerules 2–9, erect, brown, compact, 3–7 mm wide, each with 5–12(–15) spikelets; proximal glomerules occasionally on short, erect peduncles; rachis glabrous; bracts subtending inflorescence bristlelike, minutely ciliate or glabrous, inconspicuous. Spikelets bisexual, alternate, often appearing cyclic or whorled, 2–3(–4) mm; scales oblong-lanceolate. Achenes whitish or often gray or brownish or with dark interangular markings, trigonous-globose, 1–1.5(–1.9) mm, base trigonous, stipelike, short, narrowly constricted, and somewhat pitted or ribbed, apex distinctly mucronate, surface transversely tuberculate with quadrate ridges; hypogynium obsolete, represented by narrow brownish ridge at base of achene.
Fruiting summer–fall. Wet, marly, sandy, or peaty soils in marshes, bogs, savannas, moist meadows, wet pinelands, and lakeshores; 0–400 m; Ont.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Iowa, La., Md., Mich., Minn., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., Wis.; West Indies (Bahamas, Cuba).
Scleria verticillata has very close affinities with S. hirtella and S. tenella Kunth. It is relatively wide-ranging, extending along the Gulf and Atlantic coasts and inland to the Great Lakes, where it remains a very distinct species. At its southern limit in the West Indies, it tends to merge with both S. hirtella and S. tenella, producing intermediate forms and blurring its specific boundaries.