Carex prasina Wahlenb.

Specimens of apparent hybrids between Carex prasina and C. crinita are known from New Jersey and West Virginia, but their parentage has not been confirmed. The compact growth form and attractive bluish green foliage in early summer make the taxon an ideal plant for cultivation near a shady pond or stream.

Plants densely cespitose. Culms green or slightly suffused with maroon at base; flowering stems 30–80 cm, usually longer than leaves at maturity, 0.8–1.1 mm thick, glabrous but finely scabrous on angles within inflorescence. Leaves: basal sheaths 2–3, green or tinged with maroon, bladeless, very short or absent, glabrous; others green on back, white-hyaline on front; blades flat, 2–5 mm wide, glabrous. Inflorescences: peduncles of lateral spikes slender, to 4 cm, mostly shorter and usually shorter than spikes, glabrous; peduncle of terminal spike less than 10 mm, minutely scabrous; proximal bracts equaling or exceeding inflorescences; sheaths less than 3 mm; blades 2–3 mm wide. Lateral spikes 2–4, 1 per node, each overlapping 1 above, uncrowded, nodding or drooping at maturity, pistillate with 25–50 perigynia, narrowly cylindric but broader and more densely flowered at distal end (flowers 1 mm apart) than proximal end (flowers 3.5 mm apart), 15–60 × 3.5–5.5 mm. Terminal spike staminate or gynecandrous with a few pistillate flowers distally, 25–40 × 2.5–4 mm. Pistillate scales white-hyaline with broad green midrib, ovate-oblong, shorter than mature perigynia, apex cuspidate or with green awn about as long as body of scales, scabrous at tip, otherwise glabrous. Perigynia green to golden green at maturity, strongly 2-ribbed but otherwise veinless or nearly so, loosely enveloping achene, lance-ovoid, 2.5–4 × 1–1.5 mm, membranous, base with short stipe, apex tapering to flattened, often bent beak, glabrous; beak 1–1.5 mm, with minute hyaline teeth. Achenes substipitate, 1.3–2 × 1–1.2 mm. 2n = 60.

Fruiting late spring–mid summer. Rich, mesic deciduous forests, often along streams or in seepage areas, or in moist low ground associated with springs or fens; Ont., Que.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Ky., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.

Carex prasina Wahl. Sv. Vet.-Akad. Nya Handl. 24: 161. 1803
Carex miliacea Muhl.; Willd. Sp. PI. 4: 290. 1805. (Type from Pennsylvania.) Not C. miliacea
Schrank, 1789. Olamblis miliacea Raf. Good Book 26. 1840. (Based on Carex miliacea Muhl.) Carex subcompressa Steud. Syn. Cyp. 221. 1855. (Type from "Am. septr.")
Densely cespitose and not stoloniferous, from very short rootstocks, the clumps mediumsized or large, the culms 3-8 dm. high, erect, slender, remotely leafy, somewhat exceeding the leaves, sharply triangular with concave sides, asperulous and roughened on the angles above, brownish or slightly purplish-tinged at base, the basal sheaths slightly filamentose; sterile shoots elongate; leaves with well-developed blades 3-5 to a fertile culm, on the lower third, the blades light-green, flat, thin, increasing in length upwards, roughened on margins and towards apex, the uppermost 8-15 cm. long, 2. 5-4 mm. wide, the sterile-culm leaves longer and rather wider, the sheaths glabrous, very thin and white-hyaline ventrally, the ligule about as long as wide; staminate spike solitary, linear, strongly peduncled, 2-4 cm. long, 2.5-4 mm. wide, occasionally bearing some perigynia, the scales obovate-oblong, acute to short-awned, greenishwhite with green midrib; pistillate spikes 2-4 (usually 3), occasionally staminate at apex, approximate, linear, 2-6 cm. long, 3.5-5 mm. wide, the lower on long, slender, smooth peduncles, the upper on shorter peduncles, all nodding or curving, 20-50-flowered, the perigynia in few rows, ascending, closely packed, or the spikes somewhat attenuate at base; lowest bract leaflet-like, short-sheathing, somewhat exceeding inflorescence, the upper reduced, scarcely sheathing; scales ovate or obovate, mucronate or cuspidate, whitish with green 3-nerved center, shorter and slightly narrower than the perigynia ; pergynia sharply triangular, narrowly ovoid-rhomboid, 3-4 mm. long, 1.5 mm. wide, not inflated, membranaceous, green, puncticulate, nerveless or nearly so except for the two prominent lateral nerves, short-stipitate and rounded at base, tapering at apex into a smooth, triangular, often somewhat bent beak nearly the length of the body, the orifice white-hyaline, entire or emarginate; achenes broadly obovoid, 1.5 mm. long, 1.2 mm. wide, closely enveloped in lower half of perigynia, triangular with deeply concave sides and blunt angles, sessile, light-brownish, apiculate-tipped, jointed with the straight, slender style; stigmas 3, short, slender, light-reddish-brown.
Type locality: "Hab. in America boreali, Kjellman; ex herbario Bergiano." Distribution: Springy banks along shaded streamlets, Quebec and Maine to Michigan, and southward to the District of Columbia and Kentucky and in the Alleghanies to Georgia. (Specimens examined from Quebec, Maine, New Hampshire, Vermont, Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Ontario, Ohio, Michigan, Indiana, Kentucky.)

Carex prasina adalah spesies tumbuhan seperti rumput yang tergolong ke dalam famili Cyperaceae. Spesies ini juga merupakan bagian dari ordo Poales. Spesies Carex prasina sendiri merupakan bagian dari genus Carex. Nama ilmiah dari spesies ini pertama kali diterbitkan oleh Wahlenb..

Carex prasina là một loài thực vật có hoa trong họ Cói. Loài này được Wahlenb. mô tả khoa học đầu tiên năm 1803.