4. Carex nigromarginata Schwein.

Plants with short- to long-creeping rhizomes, forming dense tufts or loose colonies of tufts. Flowering stems 5–25 long, of differing lengths on the same plant, some elongate and others reduced, some of the spikes often somewhat hidden among the leaf bases, all shorter than the leaves. Leaf blades 10–40 cm long, 1.5–4.0 mm wide, ascending to arched outward (sometimes becoming prostrate later in the season), the margins mostly flat, usually dark green at maturity. Leaf sheaths with the tip truncate or nearly so, the ligule short and broadly V-shaped, the lowermost sheath bases becoming dissected into threadlike fibers with age. Inflorescences relatively dense, the lowermost bract leaflike, often longer than the inflorescence, lacking a sheath. Terminal spike staminate, sessile, 5–8(–10) mm long, linear, the staminate scales 3.0–4.3 mm long, elliptic to obovate, green, often tinged with dark reddish purple and white-margined. Lateral spikes 2–3, pistillate, mostly densely spaced near the tip of the axis, sessile or nearly so, 4–7(–10) mm long, broadly ovate in outline, with 6–15 densely spaced perigynia, the pistillate scales 3–4 mm long, lanceolate to broadly elliptic, tapered to the pointed tip, green or more commonly dark brown to purplish black with green midrib and narrow, white margins. Perigynia inconspicuous, mostly hidden by the scales, 3–4 mm long, elliptic in outline, the main body above the stalklike base elliptic to obovate in outline, distinctly longer than wide, olive green to yellowish green, sparsely short-hairy. Fruits 1.4–2.0 mm long, elliptic in outline, trigonous in cross-section, brown. 2n=34, 36. March–May.

Scattered in southern Missouri, in the Ozark, Ozark Border, and Mississippi Lowlands (Crowley’s Ridge) Divisions (eastern U.S. west to Wisconsin and Texas). Mesic and dry upland forests, often on rocky slopes, on igneous, sandstone, cherty dolomite, and coarse-sandy substrates.

Steyermark (1963) considered this species to be uncommon in Missouri, but recent field work has disclosed that it is a characteristic element of rocky, wooded slopes in most of the Ozarks, as well as in Crowley’s Ridge. The species has inconspicuous inflorescences and flowers early in the spring. The fruits, which shatter quickly at maturity, are often eaten by birds and rodents (Crins and Ball, 1983). These factors account for C. nigromarginata being overlooked and undercollected by botanists. Two varieties occur in Missouri.