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Section Vesicariae
See list of 14 species in this sectionReference: Reznicek and Ford (2002).
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1a. Carpellate scales with long, scabrous awns, the awns often equal in length to the body of scale; carpellate spikes ascending to drooping; carpellate scales often ciliate-margined
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2a. Stems produced singly or a few together from elongate rhizomes; staminate scales acute to acuminate at the apex (sometimes the lowermost scales with a short awn tip)
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2b. Stems cespitose, with short rhizomes connecting the individual stems; at least some of the staminate scales with scabrous awns
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3a. Perigynia with 5–12 veins that remain separate nearly to the apex of the beak, the bodies broad-ellipsoid to subglobose, (1.8–) 2–4.2 mm wide; achenes papillose
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4a. Widest leaves (4–) 4.5–13 mm wide; spikes (12–) 15–22 mm thick; perigynium moderately contracted to a beak 0.7–0.9 (–1) times as long as its body
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4b. Widest leaves 2.4–4 (–5) mm wide; spikes 9–14 (–15) mm thick; perigynium abruptly contracted to a beak 0.7–1.3 times as long as its body
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3b. Perigynia with 12–15 veins that converge near the base or middle of the beak (except for the 2 lateral ribs, which remain separate), the bodies ellipsoid to narrow-ovoid, 1–2.2 mm wide; achenes smooth
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5a. Perigynium somewhat inflated, nearly terete to mildly compressed, with herbaceous texture, ascending to spreading, with gaps between many of the veins wider than 3 times the width of the veins; beak of perigynium terminated by 2 straight teeth 0.3–0.9 mm long; basal leaf sheaths usually strongly tinged with anthocyanic pigments
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5b. Perigynium scarcely inflated, definitely compressed, with coriaceous texture, horizontally spreading to reflexed, with gaps between most veins less than 2 times the width of the veins; beak of perigynium terminated by 2 straight to outwardly arching teeth 0.7–2.1 (–2.8) mm long; basal leaf sheaths usually pale brown, infrequently tinged with faint anthocyanin
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6a. Perigynium beak terminated with 2 straight or slightly outcurved teeth 0.7–1.2 (–1.4) mm long; carpellate spikes 9–12 mm thick
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6b. Perigynium beak terminated with 2 strongly outcurved teeth 1.3–2.1 (–2.8) mm long; carpellate spikes 12–18 mm thick
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1b. Carpellate scales awnless or with short, smooth awns shorter than the body of the scale; carpellate spikes erect to ascending; carpellate scales eciliate
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7a. Stigmas 2; achenes biconvex; perigynia obscurely veined
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7b. Stigmas 3, achenes triangular in cross-section; perigynia distinctly veined
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8a. Perigynium beak 0.3–0.9 mm long, obscurely bidentate at tip, the terminal teeth up to 0.3 mm long; leaves filiform, with involute margins, 0.5–2.5 mm wide
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8b. Perigynium beak (1–) 1.1–4.8 mm long, with 2 distinct apical teeth (0.2–) 0.3–1.9 mm long; leaves ± flat or folded (rarey U-shaped) in cross-section, 1.5–12 (–15) mm wide
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9a. Achenes asymmetrical, with an indentation on one of the surfaces; widest perigynia (4–) 4.5–7 mm wide; lowermost bract of carpellate spikes with a blade more than 3 times as long as the inflorescence
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9b. Achenes symmetrical, lacking indentations; widest perigynia (1.5–) 2.5–3.5 (–4.5) mm wide; lowermost bract of carpellate spikes with a blade less than 3 times as long as the inflorescence (except in C. retrorsa, which has an elongate bract blade)
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10a. Bract of lowermost carpellate spike with a blade (2.5–) 3–9 times as long as the inflorescence; perigynia horizontally spreading to reflexed; staminate spike often solitary (infrequently 2 or 3), barely elevated above the crowded cluster of carpellate spikes
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10b. Bract of lowermost carpellate spike with a blade up to 2.5 (–3) times as long as the inflorescence; perigynia ascending to spreading; staminate spikes 1–3, usually well elevated above the separate carpellate spikes
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11a. Perigynium beak 2.4–4.2 (–4.8) mm long, scabrous in the apical portion
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11b. Perigynium beak (1–) 1.2–2.7 mm long, smooth
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12a. Plants cespitose, from short rhizomes, with basally firm stems; ligules of leaves longer than wide; leaf sheaths with few cross-septa connecting the longitudinal veins; perigynia ascending, mostly arranged in 6 or 7 vertical ranks
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12b. Plants colonial, from elongate rhizomes, with basally thickened and ± spongy stems; ligules as wide as long; leaf sheaths with many cross-septa connecting the longitudinal veins; perigynia spreading, mostly arranged in 8–12 vertical ranks
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13a. Leaf blades U-shaped in cross-section, white-green, 1.5–4.5 mm wide, the adaxial surface minutely papillose
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13b. Leaf blades flat to V-shaped in cross-section, pale green to green, (2.5–) 4.5–12 (–15) mm wide, smooth or rarely scabrous (note: the scabrules are easily viewed with low magnification and are more widely spaced than are the minute papillae of C. rostrata)
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Each photo represents one species in this section.