Fl. Bor.-Amer. 2: 170. 1803.
Plants cespitose. Culms straight or arcuate, 2–85 cm. Leaves of flowering stems shorter than to exceeding culms, to 20 cm × 0.8–5.4 mm; ligules on distal cauline leaves usually obsolete (except in 414.b Carex viridula subsp. brachyrrhyncha). Inflorescences: peduncles of terminal staminate spikes 0–28 mm; bracts to 18 cm × 0.6–3.4 mm; inner band of sheaths concave or truncate. Spikes: proximal pistillate spikes 1–8, contiguous or proximal distant, sessile or short-pedunculate, globose to short-cylindric, 4–17.5 × 3–11 mm; terminal staminate spike sessile or pedunculate, 5–25 × 1–3.6 mm. Scales: pistillate scales pale brown to reddish brown, 1.4–3.2 × 0.8–1.7 mm, margins pale, narrow, hyaline; staminate scales reddish brown, lanceolate to ovate, 2.3–5.2 × 0.7–2 mm, margins narrowly pale hyaline, apex obtuse to acuminate. Anthers 0.9–3.1 mm. Perigynia spreading, yellow to dark olive, 1.8–4.2 × 0.8–2 mm, apex gradually or abruptly narrowed; beak straight or reflexed less than 20°, 0.3–2.1 mm, scabrous or smooth. Achenes 1–1.8 × 0.7–1.4 mm.
Alta., B.C., Man., N.B., N.S., N.W.T., Ont., P.E.I., Que., Sask., Yukon, Alaska, Calif., Colo., Conn., Idaho, Ill., Ind., Maine, Mass., Mich., Minn., Mont., N.Dak., N.H., N.J., N.Mex., N.Y., Nev., Ohio, Oreg., Pa., R.I., Utah, Vt., Wash., Wis., Wyo., Europe, Asia, Africa (Morocco).
Subspecies 3 (3 in the flora).
|1||Proximal perigynia in each spike reflexed; beak of perigynium forming angle greater than 20° with body; staminate spike on peduncle usually more than 4.5 mm; ligules of distal cauline leaves truncate or rounded, usually well-developed.||Carex viridula subsp. brachyrrhyncha|
|1||Perigynia spreading, straight (curvature at junction of body and beak less than 25°); staminate spike subsessile to long-pedunculate; ligules of distal cauline leaves usually obsolete.||> 2|
|2||Perigynia less than 3 mm.||> 3|
|2||Perigynia 3 mm or greater.||> 4|
|3||Leaves thickened, somewhat succulent, recurved; culms less than 5 cm; staminate spike less than 6.5 mm; coastal areas of Newfoundland and Briar Island, Nova Scotia.||Carex viridula subsp. brachyrrhyncha|
|3||Leaves neither thickened nor recurved; culms greater than 5 cm; staminate spike 7+ mm; widespread.||Carex viridula subsp. viridula|
|4||Proximal pistillate spike remote, often nearly basal; perigynia and foliage often olive or dark green; culms often arcuate or sinuous; staminate spikes on peduncles 3–28 mm.||Carex viridula subsp. oedocarpa|
|4||Pistillate spikes contiguous or aggregated; foliage grayish or light green; perigynia grayish green to yellowish green; culms erect; staminate spikes on peduncles to 20 mm.||Carex viridula subsp. viridula|