26o. CAREX Linnaeus sect. STELLULATAE Kunth, Enum. Pl. 2: 399. 1837.
A. A. Reznicek
Plants cespitose, short-rhizomatous. Culms brown at base, exceeding leaves. Leaves: basal sheaths not fibrous; sheath fronts membranous, sheaths of proximal cauline leaves smooth or very weakly transversely rugose, sheaths of distal leaves with at least narrow hyaline or white-hyaline band; blades V-shaped in cross section when young, widest 0.8–5 mm wide, glabrous. Inflorescences racemose, with (1–)2–10 spikes; bracts sheathless, with inconspicuous blades, at least (1.5–)2 times as long as wide; lateral spikes gynecandrous, pistillate, or staminate, sessile, without prophylls; terminal spike gynecandrous, pistillate, or staminate. Proximal pistillate scales with apex obtuse to acute or cuspidate. Perigynia spreading, at least the proximal, veined on abaxial face, veined or veinless on adaxial face, stipitate, broadly ovate to lanceolate, usually plano-convex (to slightly biconvex in C. exilis and C. interior), base rounded to cordate, with spongy tissue, margins acutely angled, apex ± abruptly beaked, glabrous; beak 0.25–1.6 mm, with abaxial suture, margins often serrulate, apex shortly bidentate. Stigmas 2. Achenes biconvex, much smaller than bodies of perigynia; styles deciduous.
Species ca. 15 (8 in the flora): North America, Mexico, Central America, n South America, Eurasia, Australia, New Zealand, Hawaii.
Carex sect. Stellulatae is a difficult section in which differences among species can be subtle and identification may require careful observation of perigynium shape and size. Perigynia in the section rapidly narrow towards the apex of the spikes, obscuring the shape differences among species. The perigynium or two just above the staminate portion of the spikes are sometimes misshapen. Therefore, for identification purposes, it is best to examine the third or fourth perigynium above the staminate part of the spikes.
Reznicek, A. A. and P. W. Ball. 1980. The taxonomy of Carex sect. Stellulatae in North America north of Mexico. Contr. Univ. Michigan Herb. 14: 153–203.