Cyperus haspan |
Cyperus flavescens |
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haspan flatsedge |
pale flatsedge, yellow flatsedge |
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Habit | Herbs, perennial, cespitose, shortly rhizomatous. | Herbs, annual, cespitose. |
Culms | trigonous, (2–)25–60(–100) cm × 1–4 mm, soft (flattened in drying), glabrous. |
trigonous, (2–)4–30 cm × 0.4–2 mm, glabrous. |
Leaves | usually reduced to sheaths, occasionally with blades, flat to V-shaped, (3–)10–30 cm × (1–)2.5–5 mm. |
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. |
Inflorescences | heads loosely digitate; rays (5–)10–12(–15), 1–15(–20) cm; 2d order rays usually present, (1–)6–12(–25) mm; 3d order rays sometimes present, 1–6 mm; bracts 2(–3), horizontal to ascending at 30–60°, longer (3–)6–18 cm × 2–4 mm, shorter (0.5–)2.5–6.5 cm × 1–2(–3) mm. |
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. |
Spikelets | 1–15, linear-lanceoloid, ± compressed-quadrangular, 3–18 × 1–1.6 mm; floral scales 10–20(–40), laterally reddish to greenish brown, dull, often clear-edged, medially greenish, laterally 1-ribbed, medially 1-ribbed, oblong to obovate, 1–1.5(–1.9) × 0.8–1 mm, apex mucronate, glabrous except for cluster of crystalline prickles at apex. |
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. |
Flowers | stamens 3; anthers 0.3–0.5 mm; styles 0.4–0.9 mm; stigmas 0.5–0.8(–1.3) mm. |
stamens 3; anthers 0.4 mm, connectives not prolonged; styles 0.5–1 mm; stigmas 0.5–0.8 mm. |
Achenes | white or reddish brown, stipitate, globose to obovoid or ellipsoid, 0.5–0.6(–0.7) × 0.3–0.4(–0.5) mm, base nearly cuneate, stipe 0.1 × 0.1–0.2 mm, apex obtuse to acute, apiculate or entire, surfaces granular to papillose. |
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. |
Cyperus haspan |
Cyperus flavescens |
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Phenology | Fruiting summer. | Fruiting summer–early fall. |
Habitat | Swales between dunes, marshes, pond shores | Damp, often disturbed soils |
Elevation | 0–200 m (0–700 ft) | 0–800 m (0–2600 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; VA; Mexico; Central America; South America; Asia; Africa; Australia
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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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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. 151. | FNA vol. 23, p. 162. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Pycreus |
Sibling taxa | ||
Synonyms | C. autumnalis, C. haspan subsp. juncoides, C. haspan var. americanus, C. juncoides | C. flavescens var. poiformis, C. poiformis, Pycreus flavescens |
Name authority | Linnaeus: Sp. Pl. 1: 45. (1753) | Linnaeus: Sp. Pl. 1: 46. (1753) |
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