Plants cespitose, long-rhizomatous. Culms 25-75 cm, distally scabrous. Leaves 2-3.5 mm wide. Inflorescences: proximal bracts shorter than, equaling, or exceeding inflorescences; spikes separate, erect, short-pendunculate, short-oblong or elongate, 10-25 × 6-10 mm; lateral 2-3(-4) spikes pistillate; terminal spike gynecandrous. Pistillate scales light to dark brown, lanceolate, shorter or much longer and narrower than perigynia, midvein lighter colored than body, conspicuous, often raised, prominent, apex acute or acuminate, mucronate, mucro 0.5-3 mm. Perigynia ascending, gray green or whitish, faintly veined, elliptic, 2.5-4 × 1.5-2 mm, apex beakless or abruptly beaked, densely papillose; beak to 0.2 mm. Achenes nearly filling body of perigynia. 2n = ca. 106. Fruiting May-Sep. Wet meadows, marshes, fens; 20-3000 m; Greenland; Alta., B.C., Man., N.B, Nfld. and Labr., N.W.T., N.S., Ont., Que., Sask., Yukon; Alaska, Ark., Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Kans., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.C., S.Dak., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Eurasia. The plant reported by M. Raymond (1950) as Carex hartmanii Cajander is most likely this species (J. Cayouette, pers. comm.).
From Flora of Indiana (1940) by Charles C. Deam
Rather common among the dunes; infrequent elsewhere in northern Indiana. Among the dunes it is found in swales and on interdunal flats; elsewhere in marshes and low sandy or marly openings. In southern Indiana it occurs in swampy woods.
Stems 3-10 dm, arising singly or few together from long creeping rhizomes, strongly aphyllopodic, not surrounded by old sheaths from previous years (but these often persistent separately from the new stems); lvs elongate, 2-4 mm wide; spikes mostly 2-5, approximate or somewhat remote, erect or closely ascending, sessile or (especially the lower) with ±well developed peduncle, the terminal one gynaecandrous, 1-3 cm, the lateral ones pistillate, about as long or somewhat shorter; bract subtending the lowest spike sheathless or nearly so, shorter to longer than the infl; pistillate scales lanceolate to lance-ovate, brown to purplish-black with a usually paler midrib, surpassing the perigynia, tapering to an awn-tip 0.5-3 mm; perigynia 2.7-4.3 mm, beakless or very shortly beaked, rather narrowly elliptic to elliptic-obovate or elliptic-ovate, firm-walled, not strongly papillate, light gray-green, densely papillate, 2-ribbed and with 6-8 inconspicuous or obscure nerves on each face; achene trigonous, somewhat narrower and much shorter than the perigynial cavity. 2n=74, ca 100, 106. Peat-bogs, marshes, wet meadows, and other wet places; circumboreal, s. to N.C., Ky., Ark., and Calif.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.