Cyperus thyrsiflorus |
Cyperus bipartitus |
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southern flatsedge |
shining flatsedge, slender flatsedge |
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Habit | Herbs, perennial, rhizomatous. | Herbs, annual, densely cespitose, with fibrous roots. |
Culms | trigonous, (15–) 20–40(–65) cm × 0.5–1 mm, glabrous. |
roundly trigonous, 3–25(–30) cm × 0.3–1.4 mm, glabrous. |
Leaves | V-shaped, (10–)20–40 cm × 0.8–2.8(–3) mm, glabrous. |
1–3, V-shaped, 1–8 cm × 1–2 mm. |
Inflorescences | spike 1, densely oblong-cylindric, (15–)25–35(–40) × 12–18(–22) mm, (spikelets loosely spaced, 7–9 per 5 mm of rachis); rays (5–)6–8(–11), 0.5–4(–7.5) cm; bracts (4–)5–7(–8), ascending at 30º, (4–)10–30(–35) cm × (1–)2–4(–7) mm; rachilla deciduous, wings persistent, 0.4–0.5 mm wide. |
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 | (20–)40–80(–100), linear, ± cylindric, scarcely compressed, (4.5–)6–9(–11) × (0.5–) 0.6–0.7(–1) mm; floral scales persistent, (1–)2–3(–4), appressed, medially green, laterally light brown to tawny or bronze, medially (1–)3-ribbed, laterally 3-ribbed, oblong, (2.6–)2.8–3.2(–3.4) × (1–)1.2(–1.4) mm, apex acute, mucronulate, mucro to 0.1(–0.2) 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 | anthers 0.6–0.8 mm; styles (0.4–)0.6–1(–1.2) mm; stigmas persistent on achenes, prominently exserted from floral scales, (1.5–)2–3(–4) mm. |
stamens 2–3; anthers 0.4–0.5 mm, connective not prolonged; styles 0.6–1 mm; stigmas 1–1.5 mm. |
Achenes | brown to reddish brown, stipitate, narrowly oblong, 1.8–2.1 × (0.4–)0.5(–0.7) mm, stipe 0.1–0.2 × 0.1–0.2 mm, apex apiculate, acute, surfaces puncticulate. |
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 thyrsiflorus |
Cyperus bipartitus |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Dry, open woods | Emergent shorelines, ditches, puddles, often in disturbed places |
Elevation | 0–200 m (0–700 ft) | 0–1500 m (0–4900 ft) |
Distribution |
AL; FL; GA; LA; TX; Mexico; South America; West Indies |
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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Source | FNA vol. 23, p. 185. | FNA vol. 23, p. 161. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. anceps, C. dissitiflorus, C. pallens, C. regiomontanus var. pallens, C. tribrachiatus, Mariscus dissitiflorus, Mariscus pallens, Mariscus tribrachiatus | C. rivularis |
Name authority | Junghuhn: Linnaea 6: 24. (1831) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 257. (1836) |
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