Cyperus polystachyos |
Cyperus |
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many-spike flatsedge |
cyperus, flatsedge, galingale, nutsedge, umbrella-sedge |
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Habit | Herbs, perennial (annual?), cespitose. | Herbs, perennial or less often annual, cespitose or not, rhizomatous, stoloniferous, rarely tuberous. | ||||||||||||||||
Culms | trigonous or ± terete, (3–)20–45(–70) cm × (0.8–) 1.2–2 mm, glabrous. |
solitary or not, trigonous or round, glabrous or scabridulous with extrorse or antrorse (rarely retrorse) prickles. |
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Leaves | (2–) 6–10(–16), flat to V-shaped, (2–) 10–30(–60) cm × 1–4 mm. |
usually basal; ligules absent; blades keeled abaxially, flat, V-, or inversely W-shaped in cross section. |
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Inflorescences | spike 1, loosely ovoid to densely turbinate, 12–40 × 10–25 mm; rachis 3–10 mm; rays 1–8(–12), 0.5–3(–6) cm; 2d order rays absent; if rays absent, inflorescence single dense cluster of spikelets, 12–40 mm diam.; bracts (3–)4–6(–7), horizontal to ascending at 45°, flanged V-shaped, (2–)5–15(–23) cm × 1–4 mm. |
terminal, rarely pseudolateral, 1st order subumbellate to capitate, 2d order with spicate or digitately arranged spikelets, rarely a solitary spikelet; spikelets 1–150; 1st order rays unequal (rarely equal) in length, produced singly from the axils of inflorescence bracts; involucral bracts 1–22, spirally arranged at culm apex, spreading to erect, leaflike. |
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Spikelets | (5–)15–30(–40), spreading to appressed-ascending, linear-lanceoloid to linear, compressed, 8–18(–40) × (1–)1.3–1.6(–2) mm; floral scales (8–)12–25(–66), laterally stramineous to light brown, medially green, laterally ribless, medially 3–5-ribbed, oblong, (1.5–)1.8–2.4 × (1–)1.2–1.4 mm, apex acute to ± acute, mucronate. |
scales to 76, distichous, each subtending flower, cylindric to compressed, borne spicately or digitately at ends of rays (occasionally proliferous). |
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Flowers | stamens 2; anthers (0.4–)0.5–0.8 mm, connective not prolonged; styles 0.6–1(–1.4) mm; stigmas (1–)1.4–2 mm. |
bisexual [rarely unisexual], in axils of distichous floral scales, bases often decurrent onto rachilla as ± hyaline wings; perianth absent; stamens 1–3; styles linear, 2–3-fid, base deciduous or persistent; stigmas 2–3. |
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Achenes | light to dark brown, oblong, (0.8–)0.9–1.1(–1.2) × 0.4–0.5(–0.6) mm, base cuneate to ± stipelike, apex truncate, apiculate, surfaces punctate to minutely punctate with raised cells. |
biconvex, flattened, or trigonous. |
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Cyperus polystachyos |
Cyperus |
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Phenology | Fruiting summer–early fall. | |||||||||||||||||
Habitat | Shores, ditches, swales between dunes | |||||||||||||||||
Elevation | 0–200 m (0–700 ft) | |||||||||||||||||
Distribution |
AL; DC; DE; FL; GA; KY; LA; MA; MD; ME; MS; NC; NJ; NY; OK; PA; SC; TX; VA; WV; Mexico; Central America; South America; Asia; Africa
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Pantemperate and tropical |
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Discussion | Cyperus polystachyos is polymorphic. Adequate understanding of the infraspecific variations of C. polystachyos requires a worldwide examination, which is beyond the scope of this study. The segregates, C. fugax and C. filicinus, are recognized here; they have been usually accepted by recent workers (e.g., M. L. Fernald 1950; H. A. Gleason and A. Cronquist 1991). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species ca. 600 (96 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 23, p. 160. | FNA vol. 23, p. 141. | ||||||||||||||||
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | C. brizaeus, C. polystachyos var. leptostachyus, Pycreus polystachyos | |||||||||||||||||
Name authority | Rottbøll: Descr. Pl. Rar., 21. (1772) | Linnaeus: Sp. Pl. 1: 44. (1753): Gen. Pl. ed. 5, 26. (1754) | ||||||||||||||||
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