28. Carex corrugata Fernald

Map 141

Plants with short or poorly developed rhizomes, forming dense tufts or rarely loose clumps, green to light green or yellowish green. Flowering stems 15–90 cm long, erect to spreading, brown or more commonly dark reddish purple at the base. Leaf blades 1–50 cm long, 3–8 mm wide, flat. Leaf sheaths glabrous, the tip truncate or shallowly concave, the lowermost, nearly bladeless sheaths brown or more commonly dark reddish purple. Spikes 3–5 per stem, the bracts of the uppermost pistillate spikes longer than the inflorescence. Staminate spike 7–35 mm long, sessile or short-stalked, the stalk smooth. Staminate scales 3.5–4.8 mm long, narrowly oblong to narrowly ovate, white to light brown with green midrib, occasionally with sparse red spots. Pistillate spikes 5–25 mm long, 4.5–9.0 mm wide, the uppermost sessile or short-stalked, the lowermost short- to long-stalked, the stalks smooth, ascending, with 3–19 strongly overlapping perigynia, these several-ranked, in a spiral pattern around the axis. Pistillate scales 2.0–5.5 mm long, the lowermost ones with the bodies as long as or longer than the associated perigynia, ovate to broadly ovate, the tip pointed and with a short to long, rough-margined awn, white with green midrib, sometimes with reddish purple spots or streaks. Perigynia 3.5–4.5 mm long, 2.0–2.6 mm wide, 1.8–2.4 times as long as wide, ascending, elliptic to obovate in outline, the tip pointed, without a beak, slightly tapered to a broad, more or less rounded base, bluntly triangular in cross-section. Fruits 3.0–3.7 mm long, the main body (excluding beak and stalklike base) 1.8–2.3 mm long, the beak 0.3–0.6 mm long, straight. 2n=58, 60, 62. April–July.

Scattered in the Mississippi Lowlands and northward along the Mississippi River to Lincoln County; also in the Unglaciated Plains Division in southwestern Missouri (southeastern U.S. west to Missouri and Texas). Swamps and bottomland forests; less commonly in mesic upland forests on sandy soils.

This species is the characteristic member of the C. amphibola complex in the bottomlands of the Mississippi Lowlands and Mississippi River floodplain, but also occurs in bottomland forests along creeks and rivers in the Unglaciated Plains. It sometimes occurs with C. amphibola, and is apparently replaced by C. grisea in the Ozarks. Most of the older specimens were annotated by Steyermark as C. amphibola var. globosa or var. amphibola (see the treatment of C. grisea for a discussion of these taxa).