Carex swanii (Fernald) Mack.

Culms 15–75 cm, sparsely pilose. Leaves: ligules longer than wide; blades 1.5–3 mm wide, pilose. Inflorescences: lateral spikes 5–15(–19) × 2–4 mm, proximal distant; terminal spike gynecandrous, at least 1/2 flowers pistillate, (5–)11–20 mm. Pistillate scales ovate, 1.3–2.4 × 0.6–1.4 mm, apex acute to acuminate, with awn to 0.5 mm, as long as perigynia. Staminate scales ovate, 2.4–4.1 mm, apex obtuse to acuminate. Anthers 0.7–1.3(–1.6) mm. Perigynia ascending, obscurely 5–13-veined, obovate-circular, trigonous in cross section, 1.7–2.4 × 1–1.5 mm, densely pilose; beak absent. Achenes 1.4–1.8 × 0.8–1.1 mm. 2n = 54.

N.B., N.S., Ont., Que.; Ark., Conn., Del., D.C., Ga., Ill., Ind., Ky., Maine, Mass., Md., Mich., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., Tenn., Vt., Va., W.Va., Wis.

Fruiting late spring–early summer.

Dry to wet-mesic forests, scrub; 0–1000m.

Carex virescens Muhlenberg ex Schkuhr var. swanii Fernald, Rhodora 8: 183. 1906

Carex swanii (Fernald) Mackenzie, Bull. Torrey Club 37: 246. 1910.
"Carex virescens Muhl." Britt. & Brown, 111. PI. 1:316. /. 743. 1896. (And other recent authors.)
Not C. virescens Willd. 1805. Carex virescens var. minima Barratt; L. H. Bailey, Mem. Torrey Club 1: 77. 1889. (Type from
Connecticut.) Not C. minima Boullu, 1878. Carex virescens var. Swanii Fernald, Rhodora 8: 183. 1906. (Type from Manchester, Vermont.) Carex virescens var. enormis Farwell, Am. Midi. Nat. 12: 51. 1930. (Type from Michigan.)
Densely cespitose, the rootstock very short, the clumps medium-sized, the culms slender, erect or in large forms prostrate, usually 1.5-6 dm. high, but sometimes up to 13 dm., leafy, triangular, roughened above, sparsely hairy, normally exceeded by the leaves, but sometimes exceeding them, aphyllopodic, reddish-purple-tinged at base, but much less so than in Carex virescens, the basal sheaths breaking and becoming filamentose; sterile shoots elongate, conspicuous; well-developed leaves 3-6 to a culm, not bunched, the blades short-pilose (more strongly beneath), flat, erect-ascending, flaccid, dull-green, the larger 1.5-3 dm. long, 1.5-3 mm. wide, long-attenuate, the uppermost usually inserted shortly below the lowest spike (usually about 3 cm. but occasionally much more), strongly exceeding head; sheaths long, tight, short-pilose, the lowest yellowish-brown-tinged ventrally, concave at mouth, the ligule conspicuously longer than wide; spikes 2-5, oblong-cylindric to oblong-globose, 5-20 (30) mm. long, 3-5 mm. wide, the lower half of the uppermost staminate and clavate, the remainder pistillate, erect, the upper approximate and sessile or short-peduncled, the lower more or less distant and more strongly peduncled, closely 10-30-flowered, the perigynia erect-appressed in several to many rows; bracts sheathless, the lowest setaceous, 3-6 cm. long, 0.5 mm. wide, twice exceeding inflorescence, the uppermost much smaller; pistillate scales broadly ovate, small, hyaline with 3-nerved green center, narrower than the perigynia, varying from strongly awned and about the length of the perigynia (the lowest) to acuminate or acute (the uppermost) ; scales of staminate flowers hyaline with green midrib, from acuminate to strongly obtuse; perigynia 2-2.25 mm. long, 1.5 mm. wide, broadly obovoid, compressed-triangular, not inflated, green, membranaceous, strongly white-hirsute, more or less strongly nerved dorsally, sessile, short-tapering at base, beakless and rounded or slightly tapering at apex, the orifice entire; achenes obovoid, 1.5 mm. long, 1 mm. wide, triangular with concave sides, completely filling the perigynium, yellowish-brown, short-stipitate, shortly bent-apiculate, jointed with the very short thick style which is as long as the apiculation; stigmas 3, short, brownish.
Type locality (of Carex virescens var. Swanii on which C. Swanii is based) : Manchester, Vermont (M. A. Day 202).
Distribution: Dry woodlands and thickets, Nova Scotia to Wisconsin, and southward to North Carolina, Tennessee and Arkansas. (Specimens examined from Nova Scotia, Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, Ohio, Michigan, Wisconsin, Illinois, Indiana, Kentuckv, Tennessee, Missouri, Arkansas.)

Carex swanii, known as Swan's sedge or downy green sedge, is a species of flowering plant in the family Cyperaceae. It is native to eastern North America.

It was originally described as Carex virescens var. swanii Fernald in 1906, then elevated to species in 1910. The species was named for Charles Walter Swan (1838-1921), a naval surgeon and early member of the New England Botanical Club.

Carex swanii

La Carex de Swan (Carex swanii) est une plante nord-américaine de la famille des Cyperaceae.

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

Carex swanii là một loài thực vật có hoa trong họ Cói. Loài này được (Fernald) Mack. mô tả khoa học đầu tiên năm 1910.