Culms densely tufted, lateral or central, ascending or lax to decumbent, 39-47 cm × 0.8-2 mm. Leaves: basal sheaths light brown; sheaths 6-22 mm; blades ascending, midrib and 2 lateral veins developed, occasionally slightly corrugated, 19-25 cm × 5-26 mm, blades of overwintering leaves smooth or, rarely, sparsely papillose abaxially. Inflorescences: peduncles of proximal spikes erect, 0-3.4 cm, of lateral spikes 1.4-3.3(-5.3) times as long as spikes they subtend; of terminal spikes 1-2.2 cm. Bracts 7.2-17.5 cm × 2-8 mm, bract blade of distal lateral spikes linear, narrower than spikes, widest bract blade of distalmost lateral spike 0.5-3.4 mm wide. Spikes (3-)4 per culm; lateral spikes 9-33 × 3.2-4 mm; terminal spike linear to clavate, 23-24(-34) × 1.5-3 mm. Pistillate scales 2.5-3 × 1.2-1.5 mm, apex acute or apiculate. Staminate scales 3-3.5 × 1-1.5 mm, oblong-ovate, margins white-hyaline or brownish, apex obtuse or acute. Anthers 2.6-3 mm. Perigynia 3-20 per spike, usually separate, ratio of longer lateral spike length to perigynia number 1.9-3.4, ascending, conspicuously (22-)25-32-veined, (2.6-)3.2-4.1(-4.6) × 1.2-1.6 mm; beak straight, 0.5-1.4 mm. Achenes broadly ellipsoid, 1.8-2.2(-3.4) × 1-1.4 mm. 2n = 40. Fruiting spring-early summer. Dry or moist, deciduous or mixed deciduous-evergreen forests, higher elevations southward; 0-1000 m; N.S., Ont., Que.; Ala., Ark., Conn., Del., Ga., Ill., Ind., Ky., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis. The Carex laxiflora complex contains a wide array of phenotypic variation and deserves further research. F. J. Hermann (1938) proposed the name C. laxiflora var. serrulata; however, among the numerous specimens of C. laxiflora we studied, the key characteristic of ciliate-serrulate bract-sheaths varied greatly.
From Flora of Indiana (1940) by Charles C. Deam
Common in dry woods, especially beech-sugar maple, throughout the state. The form commonly referred to Carex striatula Michx. may deserve varietal recognition, at least in the southern part of its range and on the Coastal Plain where it attains the extreme of its differentiation, but in Indiana intermediates so far outnumber the extremes that all attempts to separate it even varietally have been unsuccessful. [Variety serrulata, has bract-sheaths with serrulate edges. It is] known from four counties all in the eastern half of the state. Its habitat is that of the species. The type collection (Deam no. 6458) came from a wooded ravine two miles northwest of Henryville, Clark County, May 25, 1910.
Tufted, 3-7 dm; fertile stems erect or ascending, lateral or sometimes central, sharply triangular and narrowly winged, smooth or nearly so; basal sheaths light brown; lvs of the short sterile shoots 5-25 mm wide, of the fertile shoots narrower, 2-8 mm; bract-sheaths smooth or sometimes serrulate on the angles; terminal spike staminate, 1-2.5 cm, on a peduncle 1-2 cm; pistillate spikes 2-4, 1-3 cm, slender, scattered on short or elongate, erect peduncles, none basal; at least the lower pistillate scales cuspidate or short-awned; perigynia 5-15, only slightly or scarcely overlapping, 2.6-3.8 mm, finely many-nerved as well as 2-ribbed, obtusely trigonous, obovoid, tapering to a rather short, straight or slightly outcurved beak with an oblique, entire orifice; achene trigonous; 2n=40. Dry to mesic woods; Me. and s. Que. to Del. and Md., and in the mts. to N.C., Tenn., and Ala., w. to Wis. and Ind.; s. Mex.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.