Cyperus diandrus |
Cyperus involucratus |
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umbrella flat sedge |
umbrella flatsedge, umbrella-plant |
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Habit | Herbs, annual, cespitose, with fibrous roots. | Herbs, perennial, cespitose, rhizomatous. |
Culms | trigonous, 4–25(–35) cm, glabrous. |
trigonous, 30–150 cm × 1–5(–8) mm. |
Leaves | flat, 5–20 cm × 1.5–3 mm. |
bladeless. |
Inflorescences | heads ± digitate, 12–22 mm diam.; rays 3–6, 1–6 cm; bracts 1–4, ± horizontal, flat, 1.5–15 cm × 1.5–3 mm. |
heads digitate, 15–30(–36) mm diam.; rays (14–)20–22, (2–)5–12(–20) cm; 2d order rays 0.3–3(–4) cm; 3d order rays sometimes present, 0.3–2.5 cm; bracts (4–)18–22, ± horizontal, flat, 15–27 cm × (1.5–)8–12 mm. |
Spikelets | 6–12, oblong-lanceoloid, compressed, 5–10 × 2.8–3.2 mm; floral scales 8–28, closely imbricate, stramineous to light brown or clear (marginal band bright red, spikelet thus appearing dark margined), laterally ribless, oblong to ovate, 2.5–3 × 1.6–1.9 mm. |
8–20, ovoid to linear-lanceoloid, compressed, 5–25 × 1.5–2 mm; floral scales 8–28, laterally whitish or light brown, ± hyaline, medially light brown, laterally ribless, medially 3-ribbed, 2-keeled in proximal 30–60%, deltate-ovate, 1.6–2.4 × (1–)1.2–1.5(–1.7) mm, apex acute. |
Flowers | stamens 2(–3); anthers 0.3 mm, connective apex reddish, subulate, 0.1–0.2 mm; styles 0.3–0.5 mm; stigmas 2.2–3.1 mm. |
stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
Achenes | brown, network of ridges forming isodiametric or square cells, sessile or stipitate, obovoid to ovoid, 1–1.2 × 0.5–0.6 mm, stipe, if present, 0.1 mm, apex obtuse, apiculate, surfaces minutely punctate. |
brown, sessile or stipitate, broadly ellipsoid, 0.6–0.8 × 0.4–0.6 mm, stipe if present to 0.1 mm, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus diandrus |
Cyperus involucratus |
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Phenology | Fruiting summer. | Fruiting early summer–fall. |
Habitat | Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed) | Damp, disturbed soils, ditches, stream banks |
Elevation | 0–600 m (0–2000 ft) | 0–100(–800) m (0–300(–2600) ft) |
Distribution |
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; MO; NE; NH; NJ; NY; PA; RI; VA; VT; NB; NS; ON; QC
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CA; FL; LA; TX; e Africa [Introduced in North America]
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Discussion | Cyperus involucratus has been collected in New York (R. S. Mitchell and G. C. Tucker 1997). Cyperus involucratus is widely cultivated as a water plant in greenhouses and outdoors in warm-temperate or tropical climates. It has long been misidentified in the flora as C. alternifolius Linnaeus, an endemic of Madagascar (G. C. Tucker 1983). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 161. | FNA vol. 23, p. 150. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | Pycreus diander | |
Name authority | Torrey: Cat. Pl. New York, 90. (1819) | Rottbøll: Descr. Pl. Rar., 22. (1772) |
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