Cyperus difformis |
Cyperus sphaerolepis |
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Asian flatsedge |
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Habit | Plants annual, cespitose. | |
Culms | 1–15, trigonous, 7–30 cm × 1.2–2.5 mm; soft (flattened in pressing). |
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Leaves | (2)7–22 cm × 2.2–4 mm. |
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Inflorescences | clusters head-like; dense, 7–17(35) mm wide; rays (0)1–5, 2–32 mm; longest inflorescence bract erect or nearly so, appearing as continuation of culm; other bracts horizontal to ascending. |
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Spikes | 30–120, oblong-ellipsoid, compressed; (2)3–5(6) × 0.8–1.2 mm; greenish brown to purplish brown; floral scales (6)12–20(30), obovate to orbiculate, 0.6–0.8 × 0.6–0.8 mm, stramineous to deep purple with clear margins; mid-stripe greenish, stramineous, or purplish; lateral ribs 0; medial ribs 3; apex mucronulate. |
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Flowers | anthers 0.1 mm; styles 0.1 mm; stigmas 0.1–0.3 mm. |
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Achenes | obovoid-ellipsoid, 0.6–0.8 × 0.3–0.4 mm (as long as subtending scale); base cuneate. |
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Cyperus difformis |
Cyperus sphaerolepis |
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Distribution | ||
Discussion | Disturbed, sandy or muddy soils, sand bars, roadsides, sometimes on serpentine. 100–400 m. Sisk. CA, ID; east to NJ, south to Mexico; South America; Africa, Australia, Eurasia, islands of the Pacific and Indian Oceans; Exotic. Cyperus difformis is recognized by its tight heads of small spikes with unusually small scales. The first Oregon collection was made in 2004. |
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Source | Flora of Oregon, volume 1, page 235 Barbara Wilson, Richard Brainerd, Nick Otting |
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Sibling taxa | ||
Web links |