Carex nigromarginata

Plants densely cespitose; rhizomes ascending to erect, reddish brown, 0-10 mm, stout. Culms 8-27 cm, scabrous distally; bases (remnants of old leaves) strongly fibrous. Leaf blades green, greatly exceeding culms, 1.4-4 mm wide, herbaceous, papillose to scabrous abaxially, papillose to scabrous adaxially. Inflorescences with both staminate and pistillate spikes; peduncles of staminate spikes 0.3-0.8 mm; proximal cauline bracts leaflike, usually shorter than inflorescences. Spikes: proximal pistillate spikes 2-3 (basal spikes 0); cauline spikes overlapping, proximal 2 separated by less than 7 mm, with 6-15 perigynia; staminate spikes 5.3-10 × 1.1-2.3 mm. Scales: pistillate scales pale to, usually, dark reddish brown to purplish brown, with similarly colored or narrow white margins, ovate to lanceolate, 2.9-3.7 × 1.2-2 mm, equaling or exceeding perigynia, apex acute to acuminate or cuspidate; staminate scales ovate, 3-4.3 × 1-1.8 mm, apex obtuse to acute or acuminate. Anthers 1.4-2.6 mm. Perigynia pale green, veinless, ellipsoid, 2.8-3.6 × 1-1.3 mm, longer than wide; beak straight, pale green, 0.7-1 mm, weakly ciliate-serrulate, apical teeth 0.1-0.4 mm. Stigmas 3. Achenes brown, ellipsoid, obtusely trigonous in cross section, 1.4-2 × 0.9-1.2 mm. 2n = 36.

Fruiting early Apr-late Jun. Acidic soils of rocky, dry woods, thickets, and clearings, in partial shade of mixed hardwood-pine forests or full sun along open roadsides and clearing edges, often adjacent to streams; 10-800 m; Ont.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Ky., Mass., Miss., Mo., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Va., W.Va.

Cespitose and mat-forming, fibrillose at base; stems all short but of varying length on the same plant, to ca 2 dm, mostly well surpassed by the lvs; lvs to 4 dm at maturity, mostly 2-4 mm wide; terminal spike staminate, 5-8 mm; pistillate spikes 2 or 3, 4-7 mm, sessile, all ±closely associated with the staminate spike, none basal; lowest bract often surpassing the infl; staminate scales short-cuspidate to obtusish; pistillate scales mostly dark purple except the narrow midrib, short-cuspidate to merely acute, wider and from a little shorter to a little longer than the largely concealed perigynia; perigynia 6-15, dull green or yellowish-green, sparsely short-hairy, 3-4 mm, slightly flattened, oblong-obovoid above a stipe-like base, 2-keeled, abruptly contracted into a slender beak 1 mm; achene rounded-trigonous. Dry woods, chiefly in acid soils on the coastal plain; Conn. to Fla. and La., n. in the Mississippi Valley to s. Ind. and s. Mo.; disjunct in s. Ont.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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