48. Carex gigantea Rudge (giant sedge)

Pl. 43 e–h; Map 164

Plants with long-creeping, dark brown rhizomes, forming scattered tufts. Vegetative stems generally poorly developed or absent. Flowering stems 1 to few per tuft, 40–120 cm long, smooth, light brown to somewhat reddish tinged at the base. Leaf blades 20–60 cm long, 5–16 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 5–20 cm long. Staminate spike 20–80 mm long, 2–4 mm wide, short- to long-stalked, but the stalk shorter than to about as long as the uppermost pistillate spike. Staminate scales 5.5–9.0 mm long, lanceolate to narrowly oblanceolate, tapered to a pointed or awned tip, straw-colored with a green midrib and white margins. Pistillate spikes 2–5, 30–80 mm long, 20–30 mm wide, ascending, ovate to oblong-elliptic in outline, with 20–75 perigynia. Pistillate scales 4.5–10.5 mm long, lanceolate to narrowly ovate, tapered to a pointed or short-awned tip, straw-colored with a green midrib and white margins. Perigynia 11–18 mm long, mostly spreading, narrowly ovate in outline, green to yellowish green, shiny, glabrous, the tip with the beak 6–9 mm long, the base rounded. Styles straight or weakly contorted near the base. Fruits with the main body 2.2–2.6 mm long, wider than long, unevenly diamond-shaped to nearly obtriangular in outline, widest above the middle, the angles thickened toward the middle, the sides strongly concave. May–September.

Uncommon in southeastern Missouri, almost entirely in the Mississippi Lowlands Division (southeastern U.S. west to Texas). Swamps and bottomland forests.

Elsewhere, this species occasionally may have inflorescences with 2–5 staminate spikes or the uppermost pistillate spikes staminate toward the tip (Mackenzie, 1931–1935; Gleason and Cronquist, 1991), but these conditions have not been observed in material from Missouri.