Cyperus difformis |
Cyperus owanii |
|
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
Owan's flatsedge |
|
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. |
roundly trigonous, 80–120 cm × 3–6 mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
5–12, V-shaped, 30–75 cm × 8–14 mm, septate, leathery, margins harshly scabrid. |
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 1–4 per ray, loosely ovoid to broadly ellipsoid, 12–20 × 8–12 mm; rays 6–9, 3–10(–12) cm; 2d order rays 1–4, 1–2 cm; rachis 4–12 mm; bracts 5–10, horizontal to ascending at 30°, 15–40 cm × 4–8(–11) mm; rachilla deciduous, wings persistent, hyaline, fragile, 0.3 mm wide, covering less than 1/2 of achene. |
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. |
40–80, narrowly ellipsoid to ellipsoid, roughly quadrangular to weakly flattened, 5–8 × 1.2–1.5 mm; distal spikelet spreading or ascending; floral scales (1–)2(–3), ascending, brick red, medially greenish, laterally 3–4-ribbed, medially 1–3-ribbed, green, ovate, 2.2–3.5 × 1.5–1.8 mm, apex subacute. |
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–)1–1.5 mm, filaments 4–4.7 mm; styles 0.5–0.9 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. |
brown, ellipsoid to oblong-fusiform, 1.7–1.8 × 0.7 mm, base cuneate, apex subacute and apiculate, surfaces finely puncticulate to glabrous. |
Cyperus difformis |
Cyperus owanii |
|
Phenology | Fruiting summer. | Fruiting spring–fall. |
Habitat | Disturbed, muddy soils, shallow waters | Disturbed, damp thickets, open woods |
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]
|
CA; s Africa [Introduced in North America] |
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.) |
Cyperus owanii is easily distinguished from other sedges in California by the large size, reddish spikelets, and secondary rays. It was first collected in California in 1938. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 156. | FNA vol. 23, p. 184. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. lateriflorus | Mariscus umbilensis |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Boeckeler: Flora 61: 29. (1878) |
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