Cyperus difformis |
Cyperus dipsaceus |
|
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
teasel-flatsedge, Wright's flatsedge |
|
Habit | Herbs, annual, cespitose. | Herbs, perennial, rhizomatous. |
Culms | 1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. |
trigonous, (30–)45–80 cm × (0.8–)1.2–2.2 mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
flat to V-shaped, becoming trigonous apically, 15–30 cm × 0.5–3.2 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. |
spikes oblong-cylindric, densely spicate, ± truncate at base, (9–)12–22 × (4–)6–12 mm; rays 2–4(–5), (1.5–)2.5–6 cm; bracts 4–6, longest erect or nearly so, larger ones flat or V-shaped, smaller capillary, trigonous, 3–24 cm × 0.4–3.6 mm; rachilla ± deciduous, wings 0.2–0.4 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. |
(10–)20–60, oblong to linear-lanceoloid, compressed-quadrangular, 3–9 × 2–3.4 mm; floral scales deciduous, 2–4(–8), spreading, medially green, laterally stramineous, dull whitish or pale reddish brown, often red-dotted laterally, (3–)7–9-ribbed, ovate-lanceolate, (2–)2.2–2.8(–3) × (1–)1.2–1.8 mm, apex acute, weakly 3-dentate, mucro 0.2–0.6 mm, with apical tuft of crystalline prickles. |
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 0.4–0.9 mm; styles 1–1.4 mm; stigmas 1–1.6 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. |
brown, ± stipitate, broadly ellipsoid, 1.4–1.5(–1.6) × 0.8–0.9 mm, 0.1 × 0.1–0.2 mm, apex ± truncate, apiculate, surfaces papillose. |
Cyperus difformis |
Cyperus dipsaceus |
|
Phenology | Fruiting summer. | Fruiting late summer. |
Habitat | Disturbed, muddy soils, shallow waters | Seepage slopes in montane forests |
Elevation | 0–1000 m (0–3300 ft) | 1000–1500 m (3300–4900 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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AZ; NM; Mexico |
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. 174. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. lateriflorus | C. wrightii |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Liebmann: Kongel. Danske Vidensk. Selsk. Skr., Naturvidensk. Math. Afd., ser. 5, 2: 219. (1850) |
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