Carex debilis Michx.

Carex debilis is extremely variable and has been variously subdivided into as many as six varieties or three subspecies. Only two weakly differentiated varieties can be maintained: the typical variety with broadly southern distribution and C. debilis var. rudgei, which replaces it in the Northeast, the Midwest, and the eastern mountains. Both varieties appear to hybridize with C. virescens but these hybrids have not been studied to confirm parentage.

Plants densely cespitose. Culms dark maroon at base; flowering stems 25–100 cm, as long as leaves at maturity or often longer, 0.5–1 mm thick, glabrous but scabrous within inflorescence. Leaves: basal sheaths maroon, bladeless, glabrous or rarely minutely pubescent; others grading from maroon to green on back, pale brown-hyaline or reddish brown on front, often red dotted, sometimes finely pubescent; blades flat, 2–7 mm wide, glabrous on both surfaces, margins and abaxial midribs often finely scabrous. Inflorescences: peduncles of lateral spikes slender, to 50 mm, usually shorter than spikes or only slightly longer, scabrous; of terminal spike 15–50 mm, finely scabrous; proximal bracts longer, or more often, shorter than inflorescences; sheaths 1–7 cm; blades 1–3.5 mm wide. Lateral spikes 2–5, 1 per node, well separated, erect at anthesis, soon nodding, pistillate with 10–25 perigynia attached 2–9 mm apart, linear, 25–80 × 2–3 mm. Terminal spike staminate or sometimes gynecandrous with a few pistillate flowers distally; 15–50 × 0.6–1.2 mm. Pistillate scales white-hyaline, sometimes tinged with pale brown or suffused with chestnut, with broad green midrib, finely red dotted, oblong, 2.8–6 mm, much shorter than mature perigynia, apex obtuse, acute or cuspidate, awn to 0.2 mm, glabrous, distal margin ciliate. Perigynia green to olive-green, usually red dotted, prominently 2-ribbed, finely 12–20-veined, loosely enveloping achene, fusiform to lance-ovoid, 5–9.5 × 1.1–2.2 mm, membranous, base acute, apex tapering gradually to abruptly contracted beak, glabrous or short-pubescent; beak bidentate 0.7–2 mm, including teeth to 1 mm. Achenes stipitate, 1.9–2.5 × 1–1.5 mm, stipe 0.5–1.5 mm.

Carex debilis Michx. Fl. Bor. Am. 2: 172. 1803
Car ex debilis var. y Boott, 111. Carex 92. 1860. (Type from southern United States.) Carex debilis var. prolixa L. H. Bailey, Proc. Am. Acad. 22: 105. 1886. (Based on C. debilis var. y Boott.)
Cespitose, not stoloniferous, the rootstocks very short, the clumps medium-sized or large, the culms 2.5-12 dm. high, slender but erect, exceeding the leaves, lateral and aphyllopodic or central and phyllopodic, sharply triangular, smooth or but slightly roughened on angles above, reddish-purple at base, the basal sheaths breaking and becoming somewhat filamentose ; sterile shoots aphyllopodic, conspicuous, mostly elongate; leaves with well-developed blades 2-4 to a fertile culm, not bunched, the blades flat, not stiff, pale-green, 7-30 cm. long, 2-4 mm. wide, or up to 4.5 dm. long on the sterile shoots, long-acuminate, much roughened toward the apex, the sheaths thin, yellowish-brown-tinged and reddish-dotted ventrally, smooth or puberulent dorsally, concave at mouth, the ligule longer than wide ; terminal spike staminate, more or less strongly peduncled, very narrowly linear, 1.5-5 cm. long, 1 mm. wide, rarely with a few perigynia, the scales loose, oblong-obovate or oblanceolate, obtuse or acute, white with a rough 3-nerved green center; pistillate spikes 2-4, not approximate, or the upper slightly so, drooping or weakly erect on rough slender peduncles from much shorter than to 3 times the length of the spikes; the spikes narrowly linear, 2.5-6 cm. long, 3-4 mm. wide, with 8-25 appressed-ascending perigynia overlapping in few rows, or often loosely flowered at base, the rhachis flexuose, terminating in an empty scale or scales; lower bracts leaflet-like, the upper reduced but exceeding inflorescence, the sheaths 1-4 cm. long, smooth; scales ovate or oblongovate, obtuse, slightly narrower than and from one third to one half the length of the perigynia, more or less ciliate, rounded on back, very thin, white-hyaline with green, 3-nerved, roughish center not extending to tip, not or but scarcely brownish-tinged, closely appressed, mostly disarticulating and falling before perigynia; perigynia subulate-lanceolate, 6-10 mm. long, 1.5-2 mm. wide, obscurely triangular in cross-section, but little inflated, glabrous, membranaceous, light-green or greenish-straw-colored at maturity, strongly 2-keeled and slenderly several-nerved, tapering at base, sessile or substipitate, tapering at apex into a slender, somewhat tumid, very conspicuously white-hyaline-tipped beak 1.5-2 mm. long, the tip somewhat enlarged, more or less bidentate, very oblique at orifice; achenes triangular, with sides concave below and thickened angles, in lower half of perigynium, oblong-ovoid, 2 mm. long, 1.5 mm. wide, punctate, very strongly, conspicuously, and slenderly stipitate, slender-apiculate, jointed with the flexuose slender style; stigmas 3, slender, brownish-black.
Type locality: None given, but his specimens are labeled "Basse Carolina?" (L. H. Bailey, Mem. Torrey Club 1: 34).
Distribution: Dry woods and copses, in acid soils, Florida to Texas, and northward, mostly near the coast, to Massachusetts (Martha's Vineyard), and in the interior to Indiana. (Specimens examined from Massachusetts (Martha's Vineyard), New York (Long Island), New Jersey, Pennsylvania, Delaware, Maryland, District of Columbia, Virginia, Indiana, Kentucky, North Carolina, Tennessee, South Carolina, Georgia, Alabama, Florida, Mississippi, Louisiana, Arkansas, Texas.)

Carex debilis, also known as white-edge sedge, is a species of flowering plant in the sedge family, Cyperaceae. It is native in the Eastern and Central United States and Eastern Canada.

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

Carex debilis é uma espécie de planta com flor pertencente à família Cyperaceae.

A autoridade científica da espécie é Michx., tendo sido publicada em Flora Boreali-Americana 2: 172. 1803.

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