Cyperus lecontei |
Cyperus laevigatus |
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Le Conte's flatsedge |
smooth cyperus, smooth flatsedge, smooth nutgrass |
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Habit | Herbs, perennial, cespitose, rhizomatous, with stolons, lacking tubers. | Herbs, perennial, rhizomatous. |
Culms | trigonous, 10–50 cm × 1–3 mm. |
single or close together, trigonous to ± terete, (1–)8–30(–60) cm × (0.3–)0.6–1.5(–2.2) mm, glabrous. |
Leaves | flat to V-shaped, 10–40 cm × 2–5 mm. |
blades present or reduced to sheaths, base of culm covered with reddish sheath 5–25 mm, distally short toothed 1–2 mm, or leaf blades involute, 1–7 cm × 0.3–1(–1.6) mm. |
Inflorescences | heads digitate, 10–40 mm diam.; rays 5–12, 1–12 cm; 2d order rays 1–3 cm; bracts 3–5, horizontal, flat to V-shaped, 1–15 cm × 1–2 mm. |
heads appearing lateral, spikes ± digitate, 5–15 × 5–15 mm; rays absent, sometimes 1, to 2 mm; bracts (1–)2(–3), longer bracts erect, appearing as continuation of culm, shorter bract(s) horizontal or ascending, longer bracts (1–)2–8(–12) cm × 0.5–3 mm, shorter (0.3–)1–4.5 cm × 0.2–1 mm. |
Spikelets | (1–)2–4(–6), oblong to linear, compressed, 5–25 × 2.8–3.6 mm; floral scales 20–60, stramineous or reddish green, laterally weakly 3-ribbed, ovate-elliptic, 2.5–3 × 1–1.8 mm. |
(1–)2–7(–14), whitish green to reddish, compressed-turgid, ellipsoid to oblong-lanceoloid, 4–7(–12) × (1.6–)2–3(–3.6) mm; floral scales (8–)12–22, off-white, whitish with red speckles, or with single red spot 0.5 mm wide, medially whitish, oblong-laterally ribless or weakly 2-ribbed, medially weakly 1–3-ribbed, obovate to orbiculate, 1.5–2 × (1.3–)1.6–2 mm. |
Flowers | stamens 3; anthers 1–1.3 mm; styles 0.6 mm; stigmas 1.5 mm. |
anthers (0.5–)0.7–1 mm, connective apex reddish, 0.1–0.2 mm; styles 0.8–1.2 mm; stigmas 0.7–1 mm. |
Achenes | reddish brown, sessile, ovoid, 0.7–0.8 × 0.4–0.5 mm, apex obtuse, apiculate or not, surfaces glabrous. |
gray, glossy, oblong-ellipsoid to ovoid, (1.2–)1.3–1.5(–1.8) × (0.7–)0.8–1(–1.2) mm, base cuneate to stipelike, apex apiculate, surfaces finely reticulate to papillate. |
Cyperus lecontei |
Cyperus laevigatus |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Emergent shorelines | Alkaline grasslands, hotsprings, ditches, brackish marshes |
Elevation | 0–100(–300) m (0–300(–1000) ft) | 0–1000 m (0–3300 ft) |
Distribution |
AL; FL; LA; MS; NC; SC
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AZ; CA; NC; TX; Mexico; South America; West Indies; Europe; Asia; Africa
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Discussion | Cyperus laevigatus is one of only two species of subg. Juncellus in the New World. It can be distinguished from all other New World species of Cyperus by its two stigmas and disclike, strongly flattened achene, which is borne with its face toward the rachilla. Species of subg. Pycreus, especially C. niger, have been misidentified as C. laevigatus, probably because of the dark, shiny spikelets. All species of subg. Pycreus have biconvex achenes like C. laevigatus; in species of subg. Pycreus the achene is attached with an edge toward the rachilla; in C. laevigatus the achene faces the rachilla. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 151. | FNA vol. 23, p. 164. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. dentatus var. multiradiatus, C. multiradiatus | Acorellus laevigatus, Chlorocyperus laevigatus, Juncellus laevigatus, Pycreus laevigatus |
Name authority | Torrey ex Steudel: Syn. Pl. Glumac. 2: 21. (1855) | Linnaeus: Mant. Pl. 2: 179. (1771) |
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