42. Carex sprengelii Dewey

Pl. 39 a–d; Map 158

Plants with short- to long-creeping, stout rhizomes, forming dense clumps, the sheaths of previous season’s basal leaves persisting and becoming dissected into long, hairlike fibers. Vegetative stems short, mostly reduced to basal clusters of leaves. Flowering stems 30–90 cm long, shorter than to more commonly longer than the leaves, bluntly trigonous, somewhat roughened toward the tip, brownish tinged at the base. Leaves all with well-developed blades, glabrous. Leaf blades 10–40 cm long, 2–4 mm wide, green to light green, flat. Leaf sheaths concave at the tip, the ligule wider than long and U-shaped, the ventral side somewhat papery, pale green to white, the lowermost sheath bases brownish tinged. Terminal spike staminate, sometimes with the uppermost 1–2 spikes also staminate, or mostly staminate with a few pistillate flowers at the base, the remaining 2–4 spikes pistillate. Staminate spikes 10–20 mm long, linear in outline, the scales 4.0–5.5 mm long, lanceolate, pointed at the tip, white to straw-colored with a pale green midrib. Pistillate spikes 15–35 mm long, 8–10 mm wide, mostly long-stalked, mostly nodding or drooping, the scales 3.5–5.0 mm long, ovate, tapered to a pointed tip, straw-colored or light brownish tinged, with a green midrib and lighter margins. Perigynia (4.1–)4.5–7.7 mm long, the main body oblong-elliptic in outline, somewhat inflated and circular or nearly so in cross-section, abruptly tapered to a nearly tubular beak about as long as the body with 2 papery teeth at the tip, rounded at the base, the sides with 2 prominent, longitudinal ribs on opposite sides, otherwise lacking nerves or with several faint nerves near the base, light green to nearly straw-colored, somewhat shiny. Fruits 2.0–2.5 mm long, yellowish brown, with flat to slightly concave sides and blunt angles, the short beak bent. 2n=42. May–June.

Known thus far from a single site in Atchison County (northern U.S. south to Delaware, Missouri, and Colorado; Canada). Openings of mesic upland forest on deep loess soils.