37. Carex davisii Schwein. & Torr.

Pl. 41 l–p; Map 153

C. davisii f. glabrescens Kük.

Plants with short-creeping rhizomes, forming dense tufts or clumps, the sheaths of previous season’s basal leaves sometimes persisting and becoming more or less dissected into hairlike fibers. Vegetative stems well developed, with several leaves, but shorter than the flowering stems. Flowering stems 30–90 cm long, shorter than to longer than the leaves, sharply trigonous, glabrous or somewhat hairy on the angles, strongly purplish tinged at the base. Lowermost leaves reduced to nearly bladeless sheaths. Leaf blades 1–40 cm long, 3–8 mm wide, green to dark green, flat, glabrous or more commonly hairy, at least near the base of the undersurface. Leaf sheaths concave at the tip, glabrous to evenly hairy on both sides, the ligule about as long as wide or wider than long and U-shaped to broadly V-shaped, the ventral side thin and white, the lowermost sheath bases strongly purplish tinged. Terminal spike mostly staminate, but with few to several pistillate flowers toward the tip, the 2–3 lateral spikes pistillate. Terminal spikes 15–35 mm long, linear to narrowly oblanceolate in outline, the staminate scales 3.5–7.5 mm long, lanceolate, mostly awned at the tip, white with a green midrib. Pistillate spikes 20–40 mm long, 3–6 mm wide, short- to long-stalked, mostly erect when young, but usually nodding or drooping at maturity, the scales 4.0–6.2 mm long, narrowly elliptic-ovate, tapered to a usually long awn, at least the uppermost pistillate scales with a definite awn more than half as long as the main body of the scale, white or pale green, with a green midrib. Perigynia 4.5–6.0 mm long, 2.0–2.5 mm wide, oblong-ovate in outline, broadest below the middle, circular to very bluntly trigonous in cross-section, tapered to a short beak with 2 minute, papery teeth at the tip, rounded to a stalklike base, the sides with several nerves, pale green to green, turning yellowish brown or dull orange at maturity. Fruits 2.2–2.6 mm long, yellowish brown, with deeply concave sides and blunt angles, the short beak straight or nearly so. May–July.

Scattered nearly throughout Missouri, but uncommon to absent from portions of the southern Ozarks and the Mississippi Lowlands (northeastern U.S. west to Minnesota and Texas; Canada). Bottomland forests, mesic upland forests, and margins of streams and rivers; also along roadsides and in mesic pastures and disturbed, open, floodplain areas.

Glabrous plants occur sporadically, most commonly in the southern portion of the range, and the leaves of pubescent plants vary from sparsely to densely hairy. A single collection from Perry County apparently represents a sterile hybrid between C. davisii and C. hirsutella (section Porocystis). This specimen resembles C. davisii but has the leaves narrower and more strongly hairy than are typical of that species, as well as spikes clustered more densely toward the tip of the inflorescence.