Plants loosely to densely cespitose, rhizomatous (stoloniferous in C. mackenziei). Culms brown at base. Leaves: basal sheaths fibrous, usually not persisting more than a year; sheath fronts membranous; blades V-shaped in cross section when young, glabrous. Inflorescences racemose, with (1–)2–10(–15) spikes; rachis of spikes glabrous; proximal bracts scalelike, bristlelike, or inconspicuous, sheathless; lateral spikes gynecandrous or pistillate, sessile, without prophylls; terminal spikes gynecandrous. Proximal pistillate scales with apex obtuse to acute or cuspidate. Perigynia ascending or spreading, obscurely to distinctly veined on both faces, stipitate, obovate, ovate, lanceolate, or elliptic, plano-convex in cross section, 1.5–4 mm, base rounded or truncate, with spongy tissue, margins rounded or acutely angled, apex rounded and beakless or abruptly beaked, smooth or minutely papillose, glabrous; beak sometimes inconspicuous, 0.1–0.3 mm, with or without abaxial suture, margins entire or sparsely and minutely serrulate, apex entire or bidentate. Stigmas 2. Achenes biconvex, smaller than bodies of perigynia; style deciduous. x = 27–33.
Distribution
Circumboreal, high montane regions of North America, South America, Eurasia, Australia, and New Zealand.
Discussion
Species 20–25 (16 in flora).
Members of Carex sect. Glarosae primarily occur on peatlands, shores, meadows, moist forests, and wet tundra in the colder parts of the flora area and extend northward into the arctic region and southward in the western mountains. The group is widely distributed in Eurasia and sparingly represented in the mountains of southern Asia, North America, South America, Australia, and New Zealand.
Hybrids in sect. Glareosae are rather uncommon, though to some extent neglected. Hybrids are found where parental species coexist, and they usually show intermediate ecologic preferences (H. Toivonen 1981). Hybrids are intermediate in morphology and some show hybrid vigor. They seem to be highly sterile with aborted pollen grains and empty perigynia.
Selected References
Lower Taxa
Key
| 1 | Proximal bracts long-bristlelike, many times exceeding 1–5-flowered spike; spikes widely separate. | Carex trisperma |
| 1 | Proximal bracts short-bristlelike or scalelike, often shorter than spike; spikes usually several-flowered, distal spikes approximate. | > 2 |
| 2 | Perigynia beakless or nearly so; scales white-hyaline; plants loosely cespitose. | > 3 |
| 2 | Perigynia shortly to strongly beaked; scales green or brown; plants loosely or densely cespitose. | > 4 |
| 3 | Perigynia gray-green; spikes aggregated, forming an ovoid to suborbicular head; perigynia obscurely veined. | Carex tenuiflora |
| 3 | Perigynia light green; spikes remote (proximal 2 spikes at least 1 cm apart); perigynia conspicuously veined. | Carex loliacea |
| 4 | Perigynia widest near base, apex long-beaked, margins strongly serrulate. | Carex arcta |
| 4 | Perigynia widest near middle, apex short-to long-beaked, margins entire to serrulate. | > 5 |
| 5 | Spikes 1–4(–6), closely approximate; scales tinged chestnut or red. | > 6 |
| 5 | Spikes 3–10, approximate to remote; scales tinged light green or dark brown. | > 10 |
| 6 | Culms 2–10 cm; plants densely cespitose; leaves exceeding culms; spike 1(–2). | Carex ursina |
| 6 | Culms more than 10 cm; plants usually loosely cespitose; leaves usually shorter than culms; spikes 2–4(–6). | > 7 |
| 7 | Culms often arching; leaves 1–2 mm wide, flat to channeled, gray-green; lateral spikes pistillate; perigynia gray-brown to pale brown at maturity. | Carex glareosa |
| 7 | Culms erect; leaves 1–3 mm wide, flat, green or gray-green; lateral spikes gynecandrous; perigynia brownish at maturity. | > 8 |
| 8 | Culms smooth or nearly so; leaves green; perigynia brownish yellow, apex distinctly beaked. | Carex lachenalii |
| 8 | Culms rough distally; leaves gray-green; perigynia gray-green or at maturity brown, apex scarcely to distinctly beaked. | > 9 |
| 9 | Spikes 3–4(–6), 5–10 mm, ovoid-globose; beak distinct. | Carex heleonastes |
| 9 | Spikes 2–3(–4), 3–6 mm, oblong-clavate; beak indistinct. | Carex marina |
| 10 | Terminal spike clearly clavate, staminate for at least 1/2 of length; pistillate scales equaling or exceeding, partly concealing perigynia. | Carex mackenziei |
| 10 | Terminal spike not or scarcely clavate, staminate for less than 1/2 of length; pistillate scales shorter than, not concealing perigynia. | > 11 |
| 11 | Perigynia loosely spreading, distinctly beaked, with long, asymmetric abaxial suture conspicuous; leaves green to yellowish green. | Carex brunnescens |
| 11 | Perigynia appressed-ascending, very shortly to distinctly beaked, abaxial suture inconspicuous; leaves usually gray-green. | > 12 |
| 12 | Perigynia 1.5–1.8 mm; scales tinged brown or chestnut-brown. | > 13 |
| 12 | Perigynia 1.8–3.5 mm; scales hyaline with green center, usually tinged brown at maturity. | > 14 |
| 13 | Spikes 5–8, proximal spikes separate, distal approximate. | Carex bonanzensis |
| 13 | Spikes 3–5, ± approximate. | Carex praeceptorum |
| 14 | Spikes closely approximate; scales somewhat concealing perigynia; perigynia often dark brown at maturity. | Carex arctiformis |
| 14 | Spikes, at least the proximal, remote; scales not concealing perigynia; perigynia usually light brown at maturity. | > 15 |
| 15 | Leaves (1.5–)2–4 mm wide; perigynia 1.8–3 mm; beak with small marginal teeth. | Carex canescens |
| 15 | Leaves 1–2 mm wide; perigynia 1.7–2.1 mm; beak entire, without marginal teeth. | Carex lapponica |