Carex sect. Aulocystis
Fl. Belg., 147. 1827.
Plants cespitose, short to long rhizomatous, sometimes stoloniferous. Culms brown at base, shorter than leaves. Leaves: basal sheaths not fibrous; sheath fronts membranous; blades V-shaped in cross section when young, proximal leaf blades with lateral veins equally prominent, distal leaf blades at least 2 mm, glabrous. Inflorescences racemose, with 2–8+ spikes; proximal nonbasal bracts filiform or scalelike, sheathing at least 3 mm, longer than diameter of stem; lateral spikes pistillate, androgynous, or, rarely, staminate, pedunculate, prophyllate, pistillate scales ovoid, with not more than 25 perigynia; terminal spike staminate, androgynous, or gynecandrous. Proximal pistillate scales dark brown to almost black, 1–3-veined, apex obtuse to acuminate. Perigynia ascending or spreading, purplish black at least distally, or black-mottled, veinless or weakly veined, sometimes with 2, strong, marginal veins, stipitate, lanceolate to ovate, biconvex or trigonous in cross section, less than 10 mm, base tapered to rounded, apex tapering or abruptly beaked, glabrous, setose, or hispidulous; beak straight, ± bidentate. Stigmas (2–)3. Achenes trigonous, rarely biconvex, smaller than bodies of perigynia; style deciduous.
Temperate and artic regions of North America and Eurasia, primarily in temperate Asia.
Species probably over 50 (8 in the flora).
|1||Perigynia minutely papillose; pistillate scales minutely papillose at least at center.||Carex atrofusca|
|1||Perigynia and pistillate scales not papillose.||> 2|
|2||Proximal bract sheaths expanded distally, (1.8–)2–3 mm wide at mouth, usually with wide purple band at mouth.||Carex luzulifolia|
|2||Proximal bract sheaths cylindric or slightly expanded distally, less than 2 mm wide at mouth, without or with narrow purple band at mouth.||> 3|
|3||Terminal spike gynecandrous.||Carex fuliginosa|
|3||Terminal spike staminate or androgynous.||> 4|
|4||Distance from achene apex to perigynium beak tip less than 1.5 mm; exserted portion of peduncle of proximal spike usually less than 1 cm.||> 5|
|4||Distance from achene apex to perigynium beak tip 1.5+ mm; exserted portion of peduncle of proximal spike usually more than 1 cm, sometimes shorter.||> 6|
|5||Widest leaf blades 3–6 mm wide; inflorescences more than 15 cm.||Carex albida|
|5||Widest leaf blades 1.5–3(–4) mm wide; inflorescences usually less than 15 cm.||Carex lemmonii|
|6||Perigynia glabrous on faces.||> 7|
|6||Perigynia setose or hispidulous on faces, sometimes sparsely.||> 8|
|7||Pistillate scales 3–5.8 mm; perigynia tapering to indistinct beak to 0.5 (–1) mm, faces distinctly 3–9-veined.||Carex petricosa|
|7||Pistillate scales 1.9–3.5 mm; perigynia usually abruptly beaked to 0.5– 1.5 mm, faces indistinctly veined or distinctly 9–20-veined.||Carex luzulina|
|8||Perigynia without flat margins around achene, faces distinctly 3–9-veined, apex tapering to indistinct beak to 0.5(–1) mm; leaf blades 1–3.5 mm wide.||Carex petricosa|
|8||Perigynia with narrow flat margins around achene, faces indistinctly veined, apex tapering to abrupt beak to 0.5–1.5 mm; leaf blades 3–8 mm wide.||Carex fissuricola|