Cyperus difformis |
Cyperus fuligineus |
|
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
limestone flatsedge |
|
Habit | Herbs, annual, cespitose. | Herbs, perennial, cespitose, rhizomatous. |
Culms | 1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. |
trigonous, 7–30 cm × 0.5–1 mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
V-shaped to flat, 5–20 cm × 1–2.5 mm. |
Inflorescences | heads dense, 7–17 mm diam.; when rays short, heads sessile or nearly so, then densely irregularly lobate, 12–35 mm diam.; rays 1–5, 2–32 mm; bracts 2–4, longest bract erect or nearly so, appearing as continuation of culm, other bracts horizontal to ascending, 1–22 cm × 0.5–3.5 mm, margins and keel minutely scabridulous. |
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 | 30–120, greenish brown to purplish brown, oblong-ellipsoid, compressed, (2–)3–5(–6) × 0.8–1.2 mm; floral scales (6–)12–20(–30), laterally clear margins, stramineous to deep purple, medially greenish, stramineous, or purplish, laterally ribless, medially 3-ribbed, obovate to orbiculate, 0.6–0.8 × 0.6–0.8 mm, apex mucronulate. |
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 1 or 2; anthers ovoid-ellipsoid, 0.1 mm, connective not prolonged; styles 0.1 mm; stigmas 0.1–0.3 mm. |
anthers 0.4–0.6 mm; styles 0.4–0.6 mm; stigmas 1–2 mm. |
Achenes | light brown, obovoid-ellipsoid, 0.6–0.8 × 0.3–0.4 mm (as long as subtending scale), base cuneate, apex obtuse, apiculate, surfaces finely reticulate, papillose. |
black, sessile, narrowly ellipsoid, 1–1.2 × 0.5–0.6 mm, apex obtuse, apiculate, glabrous, puncticulate, or papillose. |
Cyperus difformis |
Cyperus fuligineus |
|
Phenology | Fruiting summer. | Fruiting spring–summer. |
Habitat | Disturbed, muddy soils, shallow waters | Coastal rocks, exposed limestone in hammocks and edges of mangrove swamps |
Elevation | 0–1000 m (0–3300 ft) | 0–10 m (0–0 ft) |
Distribution |
AL; AZ; CA; FL; GA; ID; KY; LA; MS; NC; NJ; NM; OR; PA; SC; TN; TX; VA; Mexico; South America; West Indies (Puerto Rico); Central America (Nicaragua, Panama); Eurasia; Indian Ocean Islands; Pacific Islands; Australia [Introduced in North America]
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FL; West Indies |
Discussion | Cyperus difformis is naturalized in the New World and native to the Old World, where it ranges from southern Europe to southern Africa and eastward to Southeast Asia and Australia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 23, p. 156. | FNA vol. 23, p. 175. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. lateriflorus | |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Chapman: Fl. South. U.S., 511. (1860) |
Web links |