Cyperus flavescens |
Cyperus fuligineus |
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pale flatsedge, yellow flatsedge |
limestone flatsedge |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, cespitose, rhizomatous. |
Culms | trigonous, (2–)4–30 cm × 0.4–2 mm, glabrous. |
trigonous, 7–30 cm × 0.5–1 mm, glabrous. |
Leaves | 1–5, (blades often absent, base of culm with 1 reddish sheath bearing minute blade tooth 1–2 mm), (3–)10–18 cm × (0.5–)1.5–2(–2.6) mm. |
V-shaped to flat, 5–20 cm × 1–2.5 mm. |
Inflorescences | spikes 1–3, ovoid or ± digitate, 10–30 × 8–26 mm; rays 1–4(–6), 0.5–3(–9) cm; bracts 2–3, approximately horizontal, 1–12 cm × 0.5–2.5 mm. |
spike hemispheric, 7–20 mm wide; rays absent; rachis 1–3 mm; bracts 2–3, reflexed, flat, 5–12 cm × 1–2 mm; rachilla deciduous, wings 0.2 mm wide. |
Spikelets | 1–6, compressed, oblong-lanceoloid, 5–15 × (2–)2.3–2.8 mm; floral scales (4–)8–24, closely imbricate, laterally yellow to yellowish brown, margins light brown to clear, medially green, laterally ribless, medially 2–3-ribbed, 2-keeled basally, ovate, (1.5–)1.8–2.2 × 1.8 mm, apex obtuse. |
30–50, compressed, oblong-lanceoloid, 4–10 × 1.7–2.3 mm; floral scales deciduous, 5–12, dark reddish brown, laterally 3–5-ribbed, ovate, 1.5–2.2 × 1–1.6 mm, apex with mucro 0.1–0.2 mm. |
Flowers | stamens 3; anthers 0.4 mm, connectives not prolonged; styles 0.5–1 mm; stigmas 0.5–0.8 mm. |
anthers 0.4–0.6 mm; styles 0.4–0.6 mm; stigmas 1–2 mm. |
Achenes | jet black to reddish brown, slightly stipitate, obovoid, 1–1.2 × 0.8 mm, apex apiculate, surface with network of rectangular longitudinally elongate cells and transverse undulations. |
black, sessile, narrowly ellipsoid, 1–1.2 × 0.5–0.6 mm, apex obtuse, apiculate, glabrous, puncticulate, or papillose. |
Cyperus flavescens |
Cyperus fuligineus |
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Phenology | Fruiting summer–early fall. | Fruiting spring–summer. |
Habitat | Damp, often disturbed soils | Coastal rocks, exposed limestone in hammocks and edges of mangrove swamps |
Elevation | 0–800 m (0–2600 ft) | 0–10 m (0–0 ft) |
Distribution |
AL; AR; CA; DC; DE; FL; GA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV; ON; South America; West Indies; Eurasia; Africa
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FL; West Indies |
Discussion | North American populations have been distinguished as Cyperus flavescens var. poiformis; their taxonomic separation was not supported by M. L. Corcoran’s (1941) careful study. Plants of Mexico and Central America consistently have purplish rather than yellowish floral scales and may be recognized as C. flavescens var. piceus (Liebmann) Fernald (G. C. Tucker 1983, 1994). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 162. | FNA vol. 23, p. 175. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. flavescens var. poiformis, C. poiformis, Pycreus flavescens | |
Name authority | Linnaeus: Sp. Pl. 1: 46. (1753) | Chapman: Fl. South. U.S., 511. (1860) |
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