Carex sect. Rostrales
Trudy Imp. S.-Petersburgsk. Bot. Sada 18: 283. 1901.
Plants cespitose, rhizomatous. Culms yellowish or brown, without trace of red or purple at base. Leaves: basal sheaths fibrous or not; sheath fronts membranous; blades M-shaped in cross-section when young, glabrous. Inflorescences racemose, with 2–6 spikes; proximal bracts leaflike, sheathing, sheath 4+ mm, longer than diameter of stem; lateral spikes pistillate or distal lateral spike androgynous, pedunculate, prophyllate; terminal spike staminate. Proximal pistillate scales with 5–7-veined center, apex acute to awned. Perigynia spreading to somewhat reflexed, rarely ascending, veined, stipitate, ovate or lanceolate, round or rounded-trigonous in cross-section, base round-tapering, apex tapering or, rarely, contracted to beak, glabrous; beak, when present, bidentate, teeth erect. Stigmas 3. Achenes brown, oblong-ovoid or ovoid, trigonous, smaller than bodies of perigynia, smooth; style persistent.
e North America, e Asia, one species extending to tropical mountains of se Asia
Species 5 (4 in the flora).
|1||Perigynia ovate to narrowly ovate, 2.6–3.9 times as long as wide, 6.4–10.7 mm, apex contracted; beak 1.3–3 mm.||Carex turgescens|
|1||Perigynia lanceolate, 4–7 times as long as wide, (8.3–)10.5–15.6 mm, apex gradually tapered, bidentulate; beak absent.||> 2|
|2||Widest leaf blades 1.6–3.5(–4.2) mm wide; bract sheaths concave at apex; anthers 1.1– 2.7 mm.||Carex michauxiana|
|2||Widest leaf blades (3.5–)5–18 mm wide; bract sheaths prolonged, truncate to convex at apex; anthers 3–5 mm.||> 3|
|3||Larger achenes 3.4–4(–4.5) mm, (1.7–)1.8–2.4 times as long as wide; lateral spikes entirely pistillate (occasionally a few empty scales at apex), the proximal usually arching or nodding; widest leaves of vegetative shoots 8–18(–21) mm wide; proximal pistillate scales mostly 2/3 as long as to slightly longer than perigynia.||Carex folliculata|
|3||Larger achenes 2.3–3.4(–3.8) mm, 1.3–1.8 times as long as wide; lateral spikes usually with conspicuous staminate apex, erect or spreading; widest leaves of vegetative shoots (3.5–)5–12 mm wide; proximal pistillate scales mostly 1/2–2/3 as long as perigynia.||Carex lonchocarpa|