Cyperus difformis |
Cyperus pallidicolor |
|
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Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
pallid 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. |
trigonous, (10–) 30–50(–80) cm × (0.8–)1–2 mm, glabrous or occasionally minutely scabridulous on distal angles. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
3–7, M- or V-shaped, (10–)25–40(–55) cm × 2–5 mm, margins and midribs scabridulous or glabrous. |
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 3–6(–12), grayish to golden brown, loosely cylindric, (6–)10–20(–24) cm × (5–)8–11 mm; rays 0 or 1–3, to 4 cm; rachis glabrous; bracts (3–)4–6(–8), horizontal to strongly reflexed, inversely W-shaped, (3–) 10–20(–30) cm × 1–5 mm; rachilla deciduous, wings persistent, 0.3–0.5 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. |
(10–)25–60(–100), spaced 1–2(–3) mm apart, broadly ellipsoid to oblong, ± terete, 2.4–3.6 × 0.8–1.2 mm; distal spikelet spreading or ascending; floral scales persistent, 1–2(–4), appressed, laterally golden brown to dull grayish white, frequently streaked with red, medially greenish, laterally 3–4-ribbed, medially 3-ribbed, oblong, 2.6–3.3 × 1.8–2.4 mm, apex broadly rounded. |
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 0.6–0.8 mm; styles 0.8–1.2(–1.4) mm; stigmas 1.4–2 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. |
reddish brown to dark brown, stipitate, ellipsoid, (1.6–)1.8–2(–2.2) × (0.6–)0.7–0.9 mm, base cuneate to ± attenuate, apex ± acute to broadly rounded, surfaces finely papillose to essentially glabrous. |
Cyperus difformis |
Cyperus pallidicolor |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Disturbed, muddy soils, shallow waters | Clearings in montane forests |
Elevation | 0–1000 m (0–3300 ft) | 800–1200 m (2600–3900 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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AZ; NM; Mexico; Central America; South 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.) |
|
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. subambiguus var. pallidicolor |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | (Kükenthal) G. C. Tucker: in R. McVaugh & W. R. Anderson, Fl. Novo-Galiciana 13: 324. (1993) |
Web links |