51. Carex louisianica L.H. Bailey (Louisiana sedge)

Pl. 43 i–l; Map 167

Plants with long-creeping, dark-brown rhizomes, forming scattered tufts. Vegetative stems generally poorly developed or absent. Flowering stems 1 to few per tuft, 20–80 cm long, smooth, light brown to reddish tinged at the base. Leaf blades 10–40 cm long, 2–6 mm wide, dull green. Leaf sheaths slightly prolonged past the insertion point of the blade, concave at the tip, the ligule longer than wide and V-shaped, the uppermost leaf (not a bract subtending a spike) with the sheath 2–10 cm long. Staminate spike 5–70 mm long, 2–3 mm wide, long-stalked, the stalk much longer than the uppermost pistillate spike. Staminate scales 5.0–9.5 mm long, narrowly oblanceolate, tapered to a pointed tip, straw-colored with a green midrib and white margins. Pistillate spikes 1–4, 15–45 mm long, 15–30 mm wide, ascending, ovate to broadly elliptic in outline, with 10–30 perigynia. Pistillate scales 4.5–6.5 mm long, lanceolate to narrowly ovate, tapered to a pointed or short-awned tip, straw-colored with a green midrib and white margins. Perigynia 10–14 mm long, ascending to spreading, narrowly ovate in outline, green or sometimes straw-colored at maturity, usually somewhat shiny, glabrous, the tip with the beak 4.5–7.0 mm long, the base rounded. Styles strongly contorted near the base. Fruits with the main body 2.5–3.5 mm long, longer than wide, diamond-shaped in outline, widest at the middle, the angles thickened toward the middle, the sides flat to slightly concave. April–August.

Scattered in southeastern Missouri, almost entirely in the Mississippi Lowlands Division, with a single, historical collection from St. Louis city (southeastern U.S. west to Texas). Swamps and bottomland forests.