Plants cespitose, short-rhizomatous or inconspicuously rhizomatous. Culms: bases brown, rarely red tinged. Leaves: basal sheaths fibrous; sheath fronts membranous, rarely dotted red, transversely rugose, distal leaves with at least narrow hyaline or white-hyaline band; blades V-shaped in cross-section when young, glabrous. Inflorescences racemose or, rarely, 1–2 branched proximally, with 3–15 spikes; proximal bracts filiform or leaflike, sheathless; lateral spikes androgynous or pistillate, sessile, without prophylls; terminal spike androgynous. Proximal pistillate scales greenish hyaline with 1-veined center, apex obtuse to acuminate or awned. Perigynia ascending or spreading, veined or not on both faces, stipitate, lanceolate to broadly ovate or obovate, planoconvex in cross-section, widest above base, base rounded, with spongy tissue, margins acutely angled, apex tapering, often abruptly beaked, glabrous; beak 0.3–3 mm, with abaxial suture, bidentate. Stigmas 2. Achenes biconvex, smaller than bodies of perigynia; style deciduous.

Distribution

Mainly in the temperate regions of the Northern Hemisphere

Discussion

Species ca. 27 (25 in the flora).

K. K. Mackenzie (1931–1935, parts 2–3, pp. 41–53) combined sections Phaestoglochin Dumortier and Bracteosae Pax; sect. Bracteosae is now considered to be endemic to Central and South America.

Selected References

None.

Lower Taxa

Carex aggregata, Carex appalachica, Carex arkansana, Carex austrina, Carex cephaloidea, Carex cephalophora, Carex divulsa, Carex gravida, Carex hoodii, Carex hookeriana, Carex leavenworthii, Carex mesochorea, Carex muehlenbergii, Carex muricata, Carex occidentalis, Carex perdentata, Carex radiata, Carex retroflexa, Carex rosea, Carex socialis, Carex sparganioides, Carex spicata, Carex texensis, Carex tumulicola, Carex vallicola

Key

1	Proximal leaf sheaths longitudinally green-and-white-striped and with prominent green cross veins, usually loose; widest leaf blade 3–10 mm wide.	> 2
1	Proximal leaf sheaths not or indistinctly striped, without prominent cross veins, tight; widest leaf blade 0.5–4(–5) mm wide.	> 5
2	Bodies of pistillate scales 2.2–4.4 × 1.2–2.4 mm, mostly more than 1/2 length of perigynia, apex acuminate to awned; anthers 1.5–3 mm.	> 3
2	Bodies of pistillate scales 1.5–2.5 × 1.1–1.8 mm, mostly less than 1/2 length of perigynia, apex obtuse to acuminate or shortly awned; anthers 0.7–1.3 mm.	> 4
3	Fronts of leaf sheaths white, hyaline, thin, and fragile at mouth, backs not white spotted.	Carex gravida
3	Fronts of leaf sheaths yellow or brown, thick, and firm at mouth, backs often white spotted.	Carex aggregata
4	Proximal internodes of inflorescences usually not more than 1 cm, usually less than 2 times as long as proximal spikes; bodies of perigynia with narrow wing not more than 0.1 mm wide.	Carex cephaloidea
4	Proximal internodes of inflorescences usually 2+ cm, at least 2 times as long as proximal spikes; bodies of perigynia with narrow wing 0.1–0.2 mm wide, at least distally.	Carex sparganioides
5	Perigynium beak margins smooth.	> 6
5	Perigynium beak margins serrulate.	> 9
6	Pistillate scales not more than 1/3–3/4 length of perigynia; bases of perigynia not longitudinally striate on adaxial face.	Carex leavenworthii
6	Pistillate scales at least 3/4 length of perigynia; bases of perigynia longitudinally striate on adaxial side.	> 7
7	Perigynia ascending, 1.8–2.3 mm wide; pistillate scales 1.8–2.2 mm wide; achenes 1.6–2.7 mm.	Carex vallicola
7	Perigynia spreading to reflexed when mature, 1–1.8 mm wide; pistillate scales 0.8–1.6 mm wide; achenes 1.3–1.6 mm.	> 8
8	Perigynia (1.2–)1.4–1.8 mm wide, 1.5–2.3 times as long as wide; widest leaf blades 1.4–3 mm wide.	Carex retroflexa
8	Perigynia 1–1.3 mm wide, 2.3–3.1 times as long as wide; widest leaf blades 1–1.7 mm wide.	Carex texensis
9	Proximal bracts at least 2 times as long as inflorescences, 6 cm or longer; perigynia 1.9–3 mm wide.	> 10
9	Proximal bracts shorter than to less than 2 times as long as inflorescences, to 6(–11) cm; if longer, perigynia 0.7–1.8 mm wide.	> 11
10	Proximal nodes of inflorescences as long as or longer than proximal spikes; perigynium beak 0.8–1.2 mm.	Carex arkansana
10	Proximal nodes of inflorescences shorter than proximal spikes; perigynium beak (1–)1.4–1.8 mm.	Carex perdentata
11	Inflorescences lax; proximal internodes more than 2 times as long as proximal spikes.	> 12
11	Inflorescences dense; proximal internodes less than 2 times as long as proximal spikes.	> 17
12	Pistillate scales (2.5–)2.7–4.5 mm; perigynia not or only slightly spongy thickened at base, not longitudinally striate.	> 13
12	Pistillate scales 1–2.5 mm; perigynia spongy thickened at base and longitudinally striate adaxially.	> 14
13	Pistillate scales hyaline or pale brown, shorter than perigynia; perigynia 1.7–2.6 mm wide.	Carex divulsa
13	Pistillate scales brown, exceeding perigynia; perigynia 1.2–1.5 mm wide.	Carex hookeriana
14	Stigmas straight, twisted or slightly coiled, 0.03–0.06 mm wide; spongy bases of perigynia 1–1.5 mm, 0.2–0.3 times length of perigynia.	> 15
14	Stigmas usually tightly coiled, 0.05–0.1 mm wide; spongy bases of perigynia 0.5–1.3 mm, not more than 0.2 times length of perigynia.	> 16
15	Perigynia 1.5–3 times as long as wide; achenes 1–1.4 mm wide, not more than 2 times as long as wide.	Carex radiata
15	Perigynia 3–5 times as long as wide; achenes 0.8–1 mm wide, 2– 2.4 times as long as wide.	Carex socialis
16	Widest leaf blades 1.8–2.6 mm wide; base of culms 1.5–2.2 mm wide.	Carex rosea
16	Widest leaf blades 0.9–1.5 mm at widest; base of culms 0.7–1.4 mm wide.	Carex appalachica
17	Bodies of pistillate scales at least as long as and wide as perigynia, largely obscuring them.	> 18
17	Bodies of pistillate scales shorter than perigynia and narrower; perigynia easily visible.	> 22
18	Pistillate scales with awn to 1–4 mm.	> 19
18	Pistillate scales acute or with awn to 1 mm.	> 20
19	Perigynia 2.2–3 mm wide, distinctly veined abaxially; achenes 1.9–2.5 × 1.5–2 mm.	Carex austrina
19	Perigynia 1.2–1.5 mm wide, veinless or obscurely veined abaxially; achenes 1.5–1.7 × 1.1–1.2 mm.	Carex hookeriana
20	Inflorescences globose or ovoid heads, 0.8–2 cm × 6–15 mm; proximal spikes not distinct.	Carex hoodii
20	Inflorescences oblong, 1.5–5 cm × 6–10 mm; proximal spikes ± distinct.	> 21
21	Perigynia ascending to spreading; beak 0.6–1.3 mm; pistillate scales 3.4–4 × 1.6–2 mm; proximal bracts usually shorter than spikes.	Carex occidentalis
21	Perigynia erect; beak 1.2–3 mm; pistillate scales 4–5.2 × 2–2.8 mm; proximal bracts longer than spikes, often longer than inflorescences.	Carex tumulicola
22	Bodies of pistillate scales not more than 2/3 length of perigynia; inflorescences dense, spikes individually indistinct.	> 23
22	Bodies of pistillate scales at least 2/3 length of perigynia; inflorescences dense or lax.	> 24
23	Perigynium bodies elliptic to circular, widest point at 0.4–0.55 of length of body; beak 0.7–1.1 mm, apical teeth 0.3–0.5 mm.	Carex cephalophora
23	Perigynium bodies ovate, widest point at 0.25–0.4 of length of body; beak 0.3– 0.8 mm, apical teeth 0.1–0.3 mm.	Carex leavenworthii
24	Perigynium beak obscurely toothed at apex, apical teeth not more than 0.2 mm; widest leaf blades 2 mm wide.	Carex vallicola
24	Perigynium beak distinctly toothed at apex, apical teeth mostly 0.2–0.7+ mm; widest leaf blades 2 mm wide.	> 25
25	Ligules 4–8 mm, distinctly longer than wide; basal scales and sheaths frequently tinged red or purple.	Carex spicata
25	Ligules not more than 4(–5) mm, as wide as or wider than long; basal scales and sheaths brown or black, without trace of red or purple.	> 26
26	Pistillate scales, except for midvein, dark brown.	Carex muricata
26	Pistillate scales, except for midvein, hyaline or brown brown.	> 27
27	Inflorescences dense, globose to ovoid heads, 1–1.5 times as long as wide, spikes not distinct.	Carex mesochorea
27	Inflorescences somewhat lax, oblong, (1.5–)2+ times as long as wide, proximal spikes ± distinct.	> 28
28	Perigynium beak (1–)1.4–1.8 mm, apical teeth (0.5–)1.4–1.8 mm.	Carex perdentata
28	Perigynium beak 0.2–1.5 mm, apical teeth 0.2–0.6 mm.	> 29
29	Perigynia yellow-green, becoming dark brown and glossy when mature, veinless or weakly 7(–11)-veined abaxially.	Carex muricata
29	Perigynia yellow or yellow-brown when mature, strongly 9–15-veined abaxially.	> 30
30	Pistillate scales narrower than perigynia, not more than 2 mm wide, apex acute or with awn to 1.5(–2) mm.	Carex muehlenbergii
30	Pistillate scales as wide as perigynia, widest 2+ mm wide, apex with awn to 1.5–4 mm.	Carex austrina

"shortened" is not a number."widest" is not a number.