Cyperus difformis |
Cyperus ovatus |
|
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
ovateleaf flatsedge |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, cespitose, (15–)30–100 cm. |
Culms | 1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. |
not basally cormlike, trigonous, (15–)30–100 cm × 1–3 mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
V-shaped, 10–65 cm × 2–4 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 densely ovoid to cylindric, 8–17 mm wide; rays 1–6, 2–10 cm, glabrous; rachis 4–8 mm; bracts 3–9, ± horizontal, flat, 4–20 cm × 2–4 mm; rachilla persistent, wings deciduous, 0.2(–0.3) 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. |
30–80, oblong-lanceoloid, ± terete-quadrangular, 4–7 × 1.5–2 mm; distal spikelet spreading or ascending; floral scales persistent, 4–6, appressed, stramineous, laterally 3-ribbed, oblong-elliptic, 1.9–2.6 × 1.1–1.5 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 0.3–0.5 mm; styles 0.5 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. |
brown, ± stipitate, oblong-fusiform, 1.2–1.5 × 0.4–0.6 mm, apex ± acute, surfaces puncticulate. |
Cyperus difformis |
Cyperus ovatus |
|
Phenology | Fruiting summer. | Fruiting spring–summer. |
Habitat | Disturbed, muddy soils, shallow waters | Sandy soils of beaches, coastal woods |
Elevation | 0–1000 m (0–3300 ft) | 0–100 m (0–300 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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AL; FL; GA; MS; NC; SC
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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. 183. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. lateriflorus | C. cylindricus, C. deeringianus, C. litoreus, C. pollardii, C. retrorsus var. curtisii, C. retrorsus var. deeringianus, C. winkleri, Mariscus curtisii, Mariscus litoreus |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Baldwin: Trans. Amer. Philos. Soc., n. s. 2: 168. (1825) |
Web links |