Cyperus schweinitzii |
Cyperus distans |
|
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sand flatsedge, Schweinitz's flatsedge |
Piedmont flatsedge |
|
Habit | Herbs, perennial, rhizomatous. | Herbs, perennial, rhizomatous. |
Culms | trigonous, (10–)20–50 cm × (0.6–)1–2 mm, glabrous or more often scabridulous, either in distal 1/2 or over entire length; basal sheaths, 1–3, light brown, 1–4 cm, papery. |
single or close together, trigonous, (10–)40–80(–120) cm × 1.2–2.5(–5) mm, glabrous. |
Leaves | flat to V-shaped, (2–)20–35 cm × 2–6 mm, margins and keel minutely scabridulous; proximal leaves bladeless. |
2–5, pleated, (10–)20–50(–90) cm × 2–5(–10) mm. |
Inflorescences | spikes ± umbellate to slenderly (infrequently broadly) ovoid, 10–25 × 7–16 mm; rays 3–5, 1.5–8(–15) cm; bracts 3–7, erect (or declined at most 25–30° from vertical), (2.5–)8–20(–25) cm × (0.5–)1.5–6 mm; rachilla ± deciduous, wingless. |
spikes 1–4(–7), loose, broadly ovoid to ovoid-pyramidal, 25–35 × 25–35 mm; rays (4–)5–6(–8), (1–)3–8(–16) cm, glabrous; 2d order rays (0–)1–5, 5–15(–50) mm; bracts 4–7, ascending at 30–45°, pleated, (5–)20–40(–60) × (2–)3–8(–11) mm; 2d order bracts 1–4 per ray, 5–10(–30) × 0.5–1 mm, scabridulous; rachilla persistent, wingless (or very narrowly winged, not clasping achene). |
Spikelets | (1–)5–10(–20), oblong to linear-oblong, quadrangular, 7–10(–18) × (2.8–)3.2–4(–4.5) mm; floral scales deciduous, (1–)5–10(–14), spreading, laterally stramineous or dull whitish, sometimes also red-spotted, medially green, laterally 2–3-ribbed, medially 3-ribbed, broadly ovate to oblong-ovate, (2.3–)2.8–3.2 × (2–)2.4–3.2 mm, apex broadly rounded, often clear-erose, cusp 0.1–0.4 mm in proximal scales, 0.3–1 mm in distal scales. |
(10–)20–35(–45), seemingly flattened proximally from spreading floral scales, becoming terete apically, linear, (10–)13–18(–25) × 1.2–1.5(–1.6) mm; floral scales deciduous, (10–)12–20(–25), laterally light reddish brown to dark red, medially greenish, laterally ribless, medially 3–5-ribbed, oblong-ovate, 1.7–2(–2.4) × 0.9–1.2 mm, apex obtuse, barely reaching next scale, apex entire, emarginate, mucro at most 0.3 mm. |
Flowers | anthers 0.8–1.4 mm; styles 0.1–0.3 mm; stigmas 1.5–3 mm. |
anthers 0.4–0.5 mm; styles 0.3–0.6 mm; stigmas 1–1.8(–2) mm. |
Achenes | light to dark brown or nearly black, broadly ellipsoid, infrequently obovoid, 2–2.4 × 0.9–1.4 mm, base cuneate to ± stipelike, apex obtuse to broadly rounded, surfaces papillose. |
dark brown, narrowly oblong, (1.3–)1.4–1.6(–1.7) × (0.3–)0.4–0.5 mm, base cuneate to ± stipelike, apex acute, not apiculate, surfaces papillose. |
2n | = 166. |
|
Cyperus schweinitzii |
Cyperus distans |
|
Phenology | Fruiting late spring–early summer. | Fruiting summer. |
Habitat | Riverbanks, sand bars, lakeshores, sand dunes, sandy openings in woods | Marshes |
Elevation | 0–1000 m (0–3300 ft) | 0 m (0 ft) |
Distribution |
CO; IA; IL; KY; MA; MI; MN; MO; MT; NJ; NM; NY; OH; OK; PA; SD; TX; UT; WA; WI; WY; AB; MB; ON; QC; SK; Mexico (Coahuila)
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FL; NC; Mexico; South America; West Indies (Dominican Republic south through the Lesser Antilles); Asia; Africa |
Discussion | Cyperus schweinitzii is introduced, but not naturalized, in Massachusetts and Washington. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 23, p. 174. | FNA vol. 23. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. alterniflorus | C. elatus |
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 276. (1836) | Linnaeus f.: Suppl. Pl., 103. (1782) |
Web links |