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|