29. Carex flaccosperma Dewey

Pl. 37 o–q; Map 142

Plants with short or poorly developed rhizomes, mostly forming dense tufts, grayish green, sparsely to moderately glaucous. Flowering stems 15–60 cm long, ascending to more commonly spreading, straw-colored or brown at the base. Leaf blades 1–30 cm long, 4–9 mm wide, flat. Leaf sheaths glabrous, the tip extended past the insertion point of the leaf blade, slightly convex to slightly concave, the lowermost, nearly bladeless sheaths straw-colored or brown. Spikes 3–6 per stem, the bracts of the uppermost pistillate spikes longer than the inflorescence. Staminate spike 10–35 mm long, sessile or short-stalked, the stalk smooth. Staminate scales 3.8–5.3 mm long, narrowly oblong to narrowly ovate, white with green midrib, often tinged reddish brown. Pistillate spikes 10–40 mm long, 4–8 mm wide, the uppermost sessile or short-stalked, the lowermost short- to long-stalked, the stalks smooth, ascending, with 10–45 strongly overlapping perigynia, these several-ranked, in a spiral pattern around the axis. Pistillate scales 1.9–3.1 mm long, the lowermost ones with the bodies much shorter than the associated perigynia, ovate to broadly ovate, the tip pointed and with a short to long, rough-margined awn, white with green midrib. Perigynia 4.0–5.5 mm long, more than twice as long as the body of the fruit, 1.5–2.4 mm wide, 2–3 times as long as wide, ascending, elliptic obovate in outline, the tip bluntly pointed, mostly without a beak, tapered to a broad, more or less rounded base, bluntly triangular in cross-section. Fruits 2.5–3.4 mm long, the main body (excluding beak and stalklike base) 1.8–2.3 mm long, the beak 0.2–0.4 mm long, straight or nearly so. 2n=46. May–June.

Uncommon in the Mississippi Lowlands Division (southeastern Missouri north to Virginia, west to Kansas and Texas). Swamps, bottomland forests, and roadside ditches.

This species is very similar in morphology to C. glaucodea, and the two are often treated as varieties of C. flaccosperma. In addition to the differences presented in the above key to species, the two taxa have generally different overall ranges and habitats, with C. flaccosperma southeastern and inhabiting floodplain forests and swamps and C. glaucodea northeastern and growing in mostly drier sites. Where the two occasionally grow together in disturbed habitats, such as roadside ditches, they are easily separable by the thinner, grayish green, less strongly glaucous foliage of C. flaccosperma and the thicker, silvery gray, strongly glaucous foliage of C. glaucodea. Intermediates have not been detected in these populations, although rare, sterile hybrids with somewhat intermediate morphology have been reported from outside Missouri.