Carex sect. Porocystis
Fl. Belg., 147. 1827.
Plants cespitose, short-rhizomatous. Culms red-brown at base, rough distally. Leaves: basal sheaths fibrous; sheath fronts membranous; blades V-shaped in cross section when young, not more than 8 mm wide, usually pubescent, at least at junction of blade and sheath, sometimes very sparsely. Inflorescences racemose, spikes 2–6; proximal nonbasal bracts filiform or leaflike, sheathless; lateral spikes pistillate, with not more than 40(–50) perigynia, pedunculate, prophyllate; terminal spike gynecandrous or staminate. Proximal pistillate scales with apex obtuse to acuminate or awned, glabrous, sometimes margins ciliate. Perigynia spreading, abaxial face veined, adaxial face veined or veinless, with 2, strong, marginal veins, sometimes stipitate, sometimes inflated, elliptic to broadly obovate, rounded-trigonous to round in cross section, 1.7–4 mm, base rounded or tapering, apex rounded or tapering, beakless or, rarely, beaked, glabrous or pubescent; beak 0.2–0.5(–1) mm, orifice entire or subentire. Stigmas 3. Achenes trigonous, almost as large as bodies of perigynia; style deciduous.
Temperate regions of the Northern Hemisphere, Central America, and South America.
Species 10 (8 in the flora).
|1||Terminal spike staminate or, rarely, gynecandrous, then not more than 1/4 of flowers pistillate.||> 2|
|1||Terminal spike gynecandrous, at least 1/3 of flowers pistillate.||> 3|
|2||Perigynia 1–1.5 mm wide; beak absent; pistillate scales ovate, 2 times as long as wide.||Carex pallescens|
|2||Perigynia 1.5–2.2 mm wide; beak 0.2–0.5(–1) mm; pistillate scales ovate-circular, not more than 1.5 times as long as wide.||Carex torreyi|
|3||Perigynia densely pilose; widest lateral spikes 2–4 mm wide; ligules longer than wide.||> 4|
|3||Perigynia usually glabrous or pubescent, sometimes sparsely pilose; widest lateral spikes (3.5–)4–11 mm wide; ligules usually not longer than wide.||> 5|
|4||Terminal spike (5–)11–20 mm; anthers 0.7–1.3(–1.6) mm.||Carex swanii|
|4||Terminal spike 20–35(–40) mm; anthers (1–)1.6–2(–2.8) mm.||Carex virescens|
|5||Pistillate scales awned to 0.5–2 mm; perigynia papillose, pubescent.||Carex bushii|
|5||Pistillate scales awnless or awned to 0.5(–1) mm; perigynia not papillose, glabrous or sparsely pilose.||> 6|
|6||Mature perigynia nearly circular in cross section, spreading.||Carex caroliniana|
|6||Mature perigynia ± trigonous in cross section, ascending.||> 7|
|7||Leaf blades pilose on both surfaces.||Carex hirsutella|
|7||Leaf blades glabrescent, at least abaxially, sometimes persistently pilose proximally.||Carex complanata|