Cyperus difformis |
Cyperus lentiginosus |
|
---|---|---|
Asian flatsedge, smallflower umbrella sedge, variable flatsedge |
Latin American 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, (1–) 20–40(–75) cm × 1–1.5(–2.5) mm, glabrous. |
Leaves | 2–7, flat, (2–)7–22 cm × 2.2–4 mm. |
inversely W-shaped, 10–40(–70) cm × (1–)3–6(–10) 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 1(–3), broadly and loosely ovoid to oblong-ellipsoid, (15–)20–30(–50) × 20–30(–45) mm; bracts (3–)5–7(–10), ascending at 30(–45)°, inversely W-shaped, 10–30(–50) cm × (1–)3–5(–11) mm; rays (2–)3–6(–12), (1–)3–10(–17) cm; rachilla deciduous, wings ca. 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. |
(10–)25–50(–100), ± terete, (appearing compressed due to excurved apices of floral scales), (8–)12–15(–24) × (0.8–)1.1–1.4(–1.8) mm; floral scales persistent, (4–)6–8(–14), golden brown, off-white to stramineous, densely red-glandular punctate, green medially, 3–4-ribbed laterally, 3–5-ribbed medially, oblong-lanceolate, (3.2–)4–4.5 × 1.2–1.6 mm, apex blunt, mucronulate to mucronate, mucro 0.2–0.5 mm; proximal scales mucronulate, distal scales mucronate; terminal scale conduplicate. |
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 0.5–0.8(–1.4) mm; styles 0.8–1 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, ± sessile to stipitate, oblong-ellipsoid, 1.7–2 × 0.6–0.7 mm, 0.1(–0.2) × 0.2 mm, apex rounded, apiculate from dark purple style base, surfaces papillose. |
Cyperus difformis |
Cyperus lentiginosus |
|
Phenology | Fruiting summer. | Fruiting spring–summer. |
Habitat | Disturbed, muddy soils, shallow waters | Thickets, open woods |
Elevation | 0–1000 m (0–3300 ft) | 0–50 m (0–200 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]
|
FL; TX; Mexico; West Indies |
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 lentiginosus has been treated as a variety of C. tenuis (G. Kükenthal 1935–1936). The two taxa differ in the longer scales with cuspidate apices of C. lentiginosus, the inversely W-shaped leaves and bracts (those of C. tenuis are V-shaped), and the open spikes (those of C. tenuis are dense). (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. strigosus var. gracilis, C. tenuis var. lentiginosus |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Millspaugh & Chase: Publ. Field Columbian Mus., Bot. Ser. 3: 74. (1903) |
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