Carex haydenii Dewey

Carex haydenii is a species of seasonally saturated soils in open habitats. It appears to be declining in abundance with changes in land use.

Carex haydenii is often confused with C. stricta; it can be identified by the inflated perigynia that are rounded apically, acute scales, and glabrous leaves and sheaths. Only basal sheaths of C. haydenii are ladder-fibrillose. Although often sympatric with C. stricta and C. nigra, no hybrids appear to be formed.

Plants cespitose. Culms acutely angled, 30–115 cm, scabrous. Leaves: basal sheaths red-brown, indistinctly ladder-fibrillose; sheaths of proximal leaves glabrous, fronts with red-brown spots, veinless, apex U-shaped; blades 3–5 mm wide. Inflorescences: proximal bract subequal to inflorescence, 2–4 mm wide. Spikes erect; proximal 2–3 spikes pistillate, 1–5 cm × 4–6 mm, base obtuse; terminal 1–2 spikes staminate. Pistillate scales red-brown, longer than perigynia, apex acute or acuminate, awnless. Perigynia divergent, olive-brown with red-brown spots on apical 1/2, veinless, inflated, loosely enclosing achenes, obovoid, 1.5–2.8 × 1.5–2 mm, dull, apex rounded, papillose; beak green, 0.1–0.2 mm. Achenes not constricted, glaucous. 2n = 54.

N.B., Ont., Que.; Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mo., Nebr., N.H., N.Y., N.Dak., Ohio, Pa., S.Dak., Vt., Wis.

Fruiting Jun–Aug.

Wet meadows, moist prairies; 0–1,000m.

Carex acuta Linnaeus var. erecta Dewey; C. rousseaui Raymond; C. stricta Lamarck var. decora L. H. Bailey; C. stricta var. haydenii (Dewey) Kükenthal

Carex haydenii Dewey, Am. Jour. Sci. II. 18: 103. 1854
Carex acuta var. erecla Dewey, Am. Jour. Sci. 10: 265. 1826. (Type from western Massachusetts
probably.) "Carex aperta Boott" Carey, in A. Gray Man. 547. 1848.
Carex aperta var. Boott, 111. Carex 132. pi. 426. 1867. (Type from Rhode Island.) Carex aperta var. minor Olney, Caric. Bor.-Am. 10. 1871. (Based on C. aperta var. /S Boott.) Carex stricta var. decora L. H. Bailey, Bot. Gaz. 13: 85. 1888. (Type from Providence, Rhode
Island.) Carex stricta var. Haydenii Kiikenth. in Engler, Pflanzenreich 4 20 : 330. 1909. (Based on C. Haydenii Dewey.)
Rather loosely cespitose from short-prolonged rootstocks and with short ascending stolons, the new shoots at the base of the old, the culms 5-10 dm. high, slender, 3 mm. thick near base, sharply triangular and strongly roughened above, usually much exceeding the leaves, papillate, aphyllopodic, not arising from the center of the dried-up leaves of the previous year; sterile shoots aphyllopodic, conspicuous; leaves with well-developed blades 2-4 to a fertile culm, on the lower fourth but not bunched, the blades flat or nearly so to base, with slightly revolute margins, thinnish, papillate, usually 1-2 dm. long, 2-4.5 mm. wide, long-attenuate, very rough towards the apex; sterile culm-leaves longer; sheaths whitish-hyaline or yellowish-tinged ventrally, strongly purplish-red-dotted, and smooth and not at all or very sparingly filamentose, concave or truncate at mouth, smooth and rounded dorsally; ligule as long as wide or somewhat longer; terminal spike staminate (usually with an additional sessile smaller one at base), linear, 2-5 cm. long, 3 mm. wide, the scales oblong-obovate, obtuse to acutish, reddishbrown with lighter center and hyaline margins; pistillate spikes 2 or 3, erect, sessile or nearly so, approximate or a little separate, oblong or linear, 1.5-3 cm. long, 4—5 mm. wide, occasionally staminate at apex, densely flowered, scarcely attenuate at base, the perigynia 25-100, spreadingascending or spreading in few to several rows; bracts sheathless, the lowest 2 mm. wide, normally exceeded by inflorescence, the upper much reduced, biauriculate; scales ovate or lanceolate, divaricate at maturity, long-acuminate to acute, cucullate-tipped, narrower than but strongly exceeding perigynia, from dark-brown to straw-colored, with broad lighter center and hyaline margins; perigynia broadly oval to suborbicular, 2-2.5 mm. long, 1.25-1.75 mm. wide, inflated, strongly biconvex in cross-section, 2-edged and 2-ribbed (the marginal), and nerveless or obscurely few-nerved, light-brownish at maturity, membranaceous, puncticulate and resinous-dotted, minutely granular towards apex, rounded or round-tapering at base and apex, substipitate, sometimes very sparsely serrulate above, abruptly very minutely beaked, the beak 0.2 mm. long, the orifice hyaline, entire or emarginate; achenes lenticular, suborbicular, small, 1 mm. long, loosely enveloped in lower half of perigynium-body, substipitate, yellowish, abruptly apiculate, jointed with the straight or bent, slender, somewhat exserted style; stigmas 2, slender, rather short.
Type locality: "On Missouri River near Fort Pierre," Nebraska Territory {Hayden).
Distribution: Swampy meadows in calcareous districts, New Brunswick to Minnesota, and southward to New Jersey, Illinois, and Missouri. (Specimens examined from New Brunswick, Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersev, Pennsylvania, Ontario, Wisconsin, Indiana, Illinois, Minnesota, Iowa, Missouri, Nebraska.)

Carex haydenii, Hayden's sedge, is a species of flowering plant in the family Cyperaceae, native to eastern Canada and the north-central and northeastern United States. Preferring to grow in wet, shady situations, but able to tolerate full sun, it is recommended for rain gardens.

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

Carex haydenii là một loài thực vật có hoa trong họ Cói. Loài này được Dewey mô tả khoa học đầu tiên năm 1854.