Cyperus difformis |
Cyperus lancastriensis |
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
manyflower flatsedge, Porter's sedge |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, cespitose, with inconspicuous, short rhizomes scarcely visible between culm bases. |
Culms | 1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. |
basally cormlike, trigonous, (10–)20–80 cm × 1–3 mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
inversely W-shaped, 20–70 cm × 5–11 mm, adaxial surface, margins minutely scabridulous. |
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 ellipsoid to obovoid, 2.5–4.3 × 1.5–3 cm; rays 5–10, 4–20 cm, glabrous; rachis 7–14 mm; bracts 3–8, horizontal to ascending at 45°, flat, 5–35 cm × 2.5–6 mm; rachilla persistent, wings 0.5 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. |
50–90, linear-lanceoloid to linear-subulate, ± terete-quadrangular, (11–)12–13(–15) × 1.1–1.6 mm; distal spikelet spreading or ascending; floral scales persistent, 3–6(–8), appressed, whitish green or often yellow-tinted, sometimes reddish striate, laterally 4-ribbed, ovate-lanceolate, (3.9–)4.2–4.6(–4.8) × 1.6–2 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 0.7–1 mm; styles 1–1.5 mm; stigmas 2–3 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. |
yellowish brown to brown, ± stipitate, conspicuously falcate, 3–4 times long as wide, oblong, 2.2–2.6 × 0.6–0.7 mm, apex obtuse, surfaces puncticulate. |
Cyperus difformis |
Cyperus lancastriensis |
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Phenology | Fruiting summer. | Fruiting summer (Jul–Aug). |
Habitat | Disturbed, muddy soils, shallow waters | Disturbed, sunny or partly shaded places in mesic or dry-mesic soils, often on riverbanks and flood plains |
Elevation | 0–1000 m (0–3300 ft) | 0–800 m (0–2600 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; AR; DC; DE; FL; GA; KY; MD; MO; NC; NJ; OH; PA; SC; TN; VA; WV
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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.) |
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Source | FNA vol. 23, p. 156. | FNA vol. 23. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. lateriflorus | C. refractus var. lancastriensis, Mariscus lancastriensis |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Porter: in A. Gray, Manual ed. 5 issue 6, 555. (1867) |
Web links |