Carex sect. Carex
Plants cespitose, long-rhizomatous. Culms: red-brown to brown at base. Leaves: basal sheaths fibrous; sheaths membranous, sometimes pubescent at mouth; blades of at least proximal leaves septate-nodulose, M-shaped to flat in cross section, adaxial surface with 2 lateral veins more prominent than midvein, glabrous or pubescent, sometimes papillose abaxially. Inflorescences racemose, with (3–)4–10 spikes; bracts leaflike, sheathless or sheath less than 4 mm, shorter or longer than diameter of stem; proximal (1–)2–5(–6) lateral spikes pistillate, cylindric, pedunculate, prophyllate; distal 1–5 lateral spikes staminate; terminal spikes staminate. Proximal pistillate scales with apex obtuse to acuminate, sometimes awned; distal scales acute to short-awned. Perigynia ascending, 12–26-veined, stipitate, inflated, ovoid to narrowly ovoid, terete or rounded-trigonous (in C. sheldonii, C. hirta) in cross section, usually 10 mm or less, base rounded, apex contracted to beak, glabrous or pubescent; beak bidentate, teeth (0.4–)0.6–3 mm. Stigmas 3. Achenes brown, trigonous, smaller than bodies of perigynia, smooth; style persistent.
Temperate regions of the Northern Hemisphere.
Species ca. 10 (5 in the flora).
A. A. Reznicek and P. M. Catling (1982) noted that this assemblage of species, distinctive in possessing true vegetative culms as well as perigynia with long beaks and long beak teeth, forms a natural group, which is here recognized at sectional rank.
|1||Inner bands of leaf sheaths pubescent apically with spreading hairs; leaf blades often with spreading hairs abaxially.||> 2|
|1||Inner bands of leaf sheaths glabrous or scabrous apically on veins; leaf blades glabrous.||> 4|
|2||Beak of perigynium glabrous or with scattered spreading hairs on main veins, longest beak teeth (1.2–)1.5–3 mm; perigynia glabrous, (6.5–)7–12 mm; leaf blades finely papillose abaxially.||Carex atherodes|
|2||Beak of perigynium pubescent or scabrous both on and between main veins, longest beak teeth (0.4–)0.6–1.7 mm; perigynia pubescent, 4.4–7.8 mm; leaf blades not papillose abaxially.||> 3|
|3||Staminate scales with apex short-awned except sometimes the proximal, sparsely to densely spreading white-pubescent.||Carex hirta|
|3||Staminate scales with apex obtuse to acuminate, glabrous or sparsely ± appressed-pubescent near apex.||Carex sheldonii|
|4||Leaf blades finely papillose abaxially; longest ligules (6–)11–45 mm; vegetative culms hollow, flattened when pressed; longest teeth of beak (1.2–)1.5–3 mm, spreading to outcurved.||Carex atherodes|
|4||Leaf blades not papillose abaxially (sometimes scabrous proximally); longest ligules 2–12(–17) mm; vegetative culms hard, solid with parenchyma; longest teeth of beak (0.8)1.1–2.3(–2.8) mm, straight to spreading.||> 5|
|5||Inner band of distal sheaths pale brown to darker brown, usually thin at apex, ± dull, strongly veined, at length becoming ladder-fibrillose; perigynia glabrous or scabrous on main veins, 4.8–8.4 mm.||Carex laeviconica|
|5||Inner band of distal sheaths strongly reddish purple tinged, thickened at apex, thickened reddish portion opaque, smooth, and glossy, essentially veinless at very apex, not becoming ladder-fibrillose; perigynia pubescent, 6–11.5 mm.||Carex trichocarpa|