7. Carex umbellata Schkuhr ex Willd.

Pl. 29 h–k; Map 123

C. umbellata f. vicina (Dewey) Wiegand

C. abdita E. Bickn.

C. microrhyncha Mack.

Plants monoecious or rarely dioecious, with short-creeping rhizomes, usually forming dense tufts or clumps. Flowering stems 2–15 long, usually of differing lengths on the same plant, some elongate and others reduced, most of the spikes hidden among the leaf bases, all shorter than the leaves. Leaf blades 5–30 cm long, 1.5–3.0 mm wide, soft, ascending to curved outward, the margins usually curled under. Leaf sheaths with the tip shallowly to deeply concave, the ligule short and broadly V-shaped, the lowermost sheath bases becoming dissected into threadlike fibers with age. Inflorescences with 1–4 spikes, some or all of these often hidden among the leaf bases, the lowermost bract scalelike or sometimes slightly elongate and hairlike, lacking a sheath. Terminal spike staminate, sessile or nearly so, 5–10 mm long, linear, the staminate scales 3–5 mm long, obovate, green, often tinged with dark reddish purple and white-margined. Lateral spikes near the tip of the axis usually absent, occasionally 1(2), pistillate, sessile, with 3–10 densely spaced perigynia. Basal spikes usually 2–3, sometimes absent, 4–10 mm long, with 1–5 cm long stalks, broadly ovate to oblong-elliptic in outline, with 4–20 perigynia, the pistillate scales 2.5–4.0 mm long, ovate to elliptic, rounded or pointed at the tip, green with white margins, sometimes reddish tinged or straw-colored. Perigynia 2.5–3.2 mm long, ovate to elliptic in outline, the main body above the stalklike base broadly oblong-elliptic to nearly circular in outline, about as long as wide, light green, densely hairy to less commonly nearly glabrous, the beak 0.4–0.9 mm long, 1/4–1/3 as long as the main body. Fruits 1.5–1.9 mm long, broadly elliptic in outline, trigonous in cross-section, brown to dark brown. 2n=30, 32. March–May.

Scattered nearly throughout Missouri, but most common in the Ozarks (eastern U.S. and adjacent Canada west to Minnesota and Texas, locally northwest to British Columbia). Mesic to dry upland forests, upland prairies, and margins of glades, on sandstone, igneous, and cherty substrates; less commonly along roadsides and in old fields.

Plants of sandstone glades and upland prairies in western Missouri, Kansas, Oklahoma, and Texas have been segregated by some authors as C. microrhyncha Mack. (Steyermark, 1963; Great Plains Flora Association, 1986), based upon their relatively short perigynium beaks and more pointed pistillate scales. These supposed differences seem insignificant in light of the broad variation in C. umbellata, and Missouri plants are included here within a broad concept of that species.