Plants colonial, long-rhizomatous. Culms 7-60 cm, ± smooth distally. Leaves: proximal sheaths bladeless, pale brown, slender, 0.7-2.8 mm diam., not or only very sparsely papillose; ligules 2-4.5 mm, longer than wide; blades of vegetative culms 5-40 cm × 1.5-4 mm; those of fertile culms green, flat, less than 10 cm. Inflorescences 6.5-25 cm, 2-5 times longer than proximal bracts; proximal bracts 2.5-8 cm, sheath 1-3.5 cm, blade 1-1.5 cm; pistillate spikes linear, 0.8-3 cm × 3-6.5 mm. Pistillate scales purple tinged, apex broadly acute or obtuse. Perigynia 3-15, the proximal loosely arranged, green to dark brown, often obscurely veined, 3.5-5 × 1.5-2.2 mm, smooth; beak slender, cylindric, (0.4-)0.6-1.8(-2.2) mm. Achenes light to dark brown, 2.2-3 × 1.2-1.5 mm. 2n = 32. Fruiting early-mid summer. Calcareous swamps, boggy thickets and woods; 30-1600 m; Greenland; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Sask., Yukon; Alaska, Maine, Mich., Minn., Mont., N.H., N.Y., Vt., Wis.; Eurasia. M. L. Fernald (1950) pointed out that North American plants sometimes segregated as Carex saltuensis do not appear to be sufficiently distinct to warrant recognition as a separate species. T. V. Egorova (1999) recognized both C. saltuensis and C. vaginata, with two subspecies, in North America. More research is clearly needed on this complex circumpolar entity. The inclusion of C. vaginata in sect. Paniceae is uncertain. Unlike other members of the group, C. vaginata lacks papillae on abaxial leaf epidermis, peduncle, and perigynium.
Stems 2-6 dm, few together, from long rhizomes, phyllopodic, the main lvs 2-5 mm wide; terminal spike staminate, 1-2 cm; pistillate spikes 1-3, often staminate at the tip, rather loosely spreading, widely separated, the lower peduncles elongate, the upper shorter; bracts with rather loose sheaths 1-2 cm and short blades shorter than the spikes; pistillate scales shorter and narrower than the perigynia, purplish-brown, with or without a narrow green center, usually acute; perigynia usually in 2 rows, the lower
separated by internodes 2-5 mm, the upper ±overlapping, glabrous, 2-keeled, otherwise rather obscurely nerved, 3.5-5 mm, fusiform-obovoid, with a somewhat outcurved beak ca 1 mm; achene obovoid-trigonous with concave sides, nearly filling the perigynium; 2n=32. Wet woods and bogs, chiefly in calcareous districts; circumboreal, s. in Amer. to Me., n. N.Y., n. Mich., n. Minn., Sask., and B.C. (C. saltuensis, the Amer. plants)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.