Cyperus oxylepis |
Cyperus difformis |
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sharpscale flatsedge |
Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
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Habit | Herbs, perennial, cespitose, coarse, (culms, leaves, bracts, and rays viscid). | Herbs, annual, cespitose. |
Culms | roundly trigonous, 10–50 cm × 0.9–2.4 mm. |
1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. |
Leaves | adaxial face concave, becoming flat to trigonous apically, 10–46 cm × 1.5–4 mm, margins involute. |
2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
Inflorescences | spikes ovoid, 1–5.5 cm wide; rays usually 3–6, 0.5–5 cm, glabrous; sometimes absent in small plants; if absent, inflorescence a congested head of spikelets 1–3.5 cm diam.; 2d order rays 0–3, 1–3 cm; bracts 3–5, vertical to ascending at 45°, 2.5–25 cm × 1.2–4 mm, margins involute; 2d order bracts 0–2, 5–20 mm; rachilla persistent, wingless. |
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. |
Spikelets | 5–24, greenish yellow to golden brown, oblong to linear-lanceoloid, quadrangular, strongly compressed, 7–20(–30) × 2.5–4(–6) mm; floral scales 10–20(–40), spreading, pale green to stramineous, laterally 2–3-ribbed, ovate-lanceolate, 3.1–4 × 1.5–2.4 mm, apex with mucro 0.2–0.8 mm. |
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. |
Flowers | anthers 0.6–0.8 mm; styles 0.8–1.6 mm; stigmas 1–1.4 mm. |
stamens 1 or 2; anthers ovoid-ellipsoid, 0.1 mm, connective not prolonged; styles 0.1 mm; stigmas 0.1–0.3 mm. |
Achenes | light to dark brown, rarely somewhat reddish, stipitate, ellipsoid, 2–2.4 × 0.5–0.8 mm, base cuneate, stipe whitish, spongy, 0.2–0.3 × 0.2–0.4 mm, apex acute, persistent style forming beak 0.5–1.2 mm, surfaces glabrous or finely papillose. |
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. |
Cyperus oxylepis |
Cyperus difformis |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Ditches and disturbed places in marshes, often in saline soil | Disturbed, muddy soils, shallow waters |
Elevation | 0–100 m (0–300 ft) | 0–1000 m (0–3300 ft) |
Distribution |
AR; FL; GA; LA; MS; SC; TX; Mexico; South America [Introduced in North America]
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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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Discussion | Cyperus oxylepis is easily recognized by its sticky leaves, culms, and bracts (in living plants), involute leaves,and golden brown spikelets. The ovate-lanceolate floral scales and the ellipsoid, brownish achene with a persistent beak distinguish C. oxylepis from other species with deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 171. | FNA vol. 23, p. 156. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | C. lateriflorus | |
Name authority | Nees ex Steudel: Syn. Pl. Glumac. 2: 25. (1855) | Linnaeus: Cent. Pl. II, 6. (1756) |
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