Cyperus pumilus |
Cyperus bipartitus |
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low flatsedge |
shining flatsedge, slender flatsedge |
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Habit | Herbs, annual, cespitose. | Herbs, annual, densely cespitose, with fibrous roots. |
Culms | trigonous, 1–35 cm × 0.5–1 mm, glabrous. |
roundly trigonous, 3–25(–30) cm × 0.3–1.4 mm, glabrous. |
Leaves | flat, 5–20 cm × 1–2 mm. |
1–3, V-shaped, 1–8 cm × 1–2 mm. |
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. |
spike 1, loosely ovoid, compressed, 7–14 × 9–14 mm; rays 1–4, to 2(–3) cm; bracts 2–3, horizontal to ascending at 30(–45)°, V-shaped to flat, 1–12 cm × 0.5–1.5 mm. |
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. |
3–5(–8), flattened, oblong to oblong-lanceoloid, 8–18 × 2–2.6(–3) mm; floral scales (6–)10–26(–32), closely imbricate, laterally light to dark brown, medially light brown, laterally ribless, medially 2–3-ribbed, 2-keeled, oblong to ovate, 1.9–2.7 × 1.8–2.3 mm, apex obtuse. |
Flowers | stamens 1–2; anthers 0.2 mm; styles 0.5 mm; stigmas 0.3 mm. |
stamens 2–3; anthers 0.4–0.5 mm, connective not prolonged; styles 0.6–1 mm; stigmas 1–1.5 mm. |
Achenes | dark brown to black, sessile, obovoid, 0.6 × 0.4 mm, apex obtuse, apiculate, surfaces minutely punctate. |
black, network of ridges forming isodiametric or square cells, sessile, obovoid to ovoid, 1–1.3(–1.5) × (0.6–)0.8 mm, apex apiculate, surfaces minutely punctate. |
Cyperus pumilus |
Cyperus bipartitus |
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Phenology | Fruiting spring–summer. | Fruiting summer. |
Habitat | Disturbed, sandy soils | Emergent shorelines, ditches, puddles, often in disturbed places |
Elevation | 0–50 m (0–200 ft) | 0–1500 m (0–4900 ft) |
Distribution |
FL; Asia; Africa (including Madagascar); Indian Ocean Islands; Pacific Islands; Australia [Introduced in North America; West Indies (introduced)] |
AL; AR; AZ; CA; CO; CT; DC; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; ON; QC; Mexico; Central America; South America
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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.) |
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Source | FNA vol. 23, p. 163. | FNA vol. 23, p. 161. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. leucolepis, Juncellus leucolepis, Pycreus pumilus | C. rivularis |
Name authority | Linnaeus: Cent. Pl. II, 6. (1756) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 257. (1836) |
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