Cyperus difformis |
Cyperus grayi |
|
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
Gray's flatsedge, Gray's sedge |
|
Habit | Herbs, annual, cespitose. | Herbs, perennial, cespitose, rhizomatous. |
Culms | 1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous. |
basally cormlike, trigonous, 5–40 cm × 0.5–1.3 mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
V-shaped, 5–25 cm × 1–3 mm, slightly minutely scabridulous abaxially on margins, midrib. |
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 loosely ± globose, 6–20 mm wide; rays 1–8 cm; rachis 1–4 mm; bracts 3–8, ascending, V-shaped, 3–20 cm × 1–3 mm; rachilla deciduous, wings hyaline, 0.6 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. |
3–18(–28), oblong-lanceoloid, compressed, 3–12 × 1.8–2.5 mm; floral scales deciduous, 2–11, yellowish brown to reddish brown, laterally 3–4-ribbed, ovate, 2–2.8 × 1.6–2.2 mm, apex mucronulate. |
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 0.4–0.6 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. |
dark brown, ± stipitate, ellipsoid, 1.5–2 × 0.7–1 mm, apex obtuse, apiculate surfaces glabrous or puncticulate. |
2n | = 166. |
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Cyperus difformis |
Cyperus grayi |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Disturbed, muddy soils, shallow waters | Coastal dunes, well-drained woods, railroad yards |
Elevation | 0–1000 m (0–3300 ft) | 0–200 m (0–700 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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CT; DE; GA; MA; MD; NC; NH; NJ; NY; PA; RI; SC; VA |
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. 179. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. lateriflorus | C. filiculmis var. grayi, C. filiculmis var. oblitus |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 268. (1836) |
Web links |