Cyperus pumilus |
Cyperus schweinitzii |
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low flatsedge |
sand flatsedge, Schweinitz's flatsedge |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, rhizomatous. |
Culms | trigonous, 1–35 cm × 0.5–1 mm, glabrous. |
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. |
Leaves | flat, 5–20 cm × 1–2 mm. |
flat to V-shaped, (2–)20–35 cm × 2–6 mm, margins and keel minutely scabridulous; proximal leaves bladeless. |
Inflorescences | heads ± digitate, 8–26 mm diam.; rays 1–6, 0.5–5 cm; bracts 3–4, ± horizontal, flat, 3–18 cm × 1–2 mm. |
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. |
Spikelets | 6–25, ovoid to linear-lanceoloid, compressed, 4–15 × 1–2 mm; floral scales 8–28(–40), clear, laterally ribless, ovate, 1.4–1.6 × 0.8 mm, apex awned, awn excurved, 0.3–0.5 mm. |
(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. |
Flowers | stamens 1–2; anthers 0.2 mm; styles 0.5 mm; stigmas 0.3 mm. |
anthers 0.8–1.4 mm; styles 0.1–0.3 mm; stigmas 1.5–3 mm. |
Achenes | dark brown to black, sessile, obovoid, 0.6 × 0.4 mm, apex obtuse, apiculate, surfaces minutely punctate. |
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. |
2n | = 166. |
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Cyperus pumilus |
Cyperus schweinitzii |
|
Phenology | Fruiting spring–summer. | Fruiting late spring–early summer. |
Habitat | Disturbed, sandy soils | Riverbanks, sand bars, lakeshores, sand dunes, sandy openings in woods |
Elevation | 0–50 m (0–200 ft) | 0–1000 m (0–3300 ft) |
Distribution |
FL; Asia; Africa (including Madagascar); Indian Ocean Islands; Pacific Islands; Australia [Introduced in North America; West Indies (introduced)] |
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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Discussion | Cyperus pumilus is distinctive because it is our only distigmatic Cyperus with awned floral scales. Cyperus hyalinus Vahl, a southeastern Asian and Australian species, has recently been collected in Miami-Dade County, Florida (Mears s.n., EIU, VSC). This is an aberrant species sometimes placed in the monotypic genus Queenslandiella as Q. hyalina (Vahl) F. Ballard; it differs from C. pumilus in having deciduous rachillae as well as deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 163. | FNA vol. 23, p. 174. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. leucolepis, Juncellus leucolepis, Pycreus pumilus | C. alterniflorus |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 276. (1836) |
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