Cyperus involucratus |
Cyperus houghtonii |
|
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umbrella-plant |
Houghton's flatsedge |
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Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose, bases cormose, rhizomatous. |
Culms | trigonous, 30–150 cm × 1–5(–8) mm. |
trigonous, 5–50 cm × 0.5–1.5 mm, glabrous. |
Leaves | bladeless. |
V-shaped, 12–30 cm × 1–6 mm. |
Inflorescences | 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. |
spikes ± globose to broadly ovoid, 8–20 mm wide; rays 1–8 cm; rachis 2–5 mm, glabrous; bracts 3–8, weakly ascending, flat, 3–20 cm × 1–3.5 mm; rachilla deciduous, wingless. |
Spikelets | 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. |
3–18, compressed, ovoid to oblong-lanceoloid, 4–15 × 2.6–3.4 mm; floral scales deciduous, 3–18, laterally stramineous to reddish brown, laterally 3–4-ribbed, broadly ovate, 1.8–2.5 × 1.3–1.6 mm, apex with mucro 0.1–0.2 mm. |
Flowers | stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
anthers 0.5–0.7 mm; styles 0.4–0.6 mm; stigmas 1–1.5 mm. |
Achenes | 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. |
dark brown, sessile, broadly ellipsoid, 1.5–2 × 1–1.5 mm, apex obtuse, apiculate, surface glabrous, puncticulate, or papillose. |
2n | = 168, 170, 172. |
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Cyperus involucratus |
Cyperus houghtonii |
|
Phenology | Fruiting early summer–fall. | Fruiting summer. |
Habitat | Damp, disturbed soils, ditches, stream banks | Riverbanks, sand bars, lakeshores, sand dunes, sandy openings in woods, especially among Jack pines |
Elevation | 0–100(–800) m [0–300(–2600) ft] | 0–1100 m [0–3600 ft] |
Distribution |
CA; FL; LA; TX; e Africa [Introduced in North America] |
IL; IN; MA; MD; ME; MI; MN; NH; NJ; NY; OH; PA; VA; VT; WI; WV; MB; ON; QC
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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. 150. | FNA vol. 23, p. 175. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rottbøll: Descr. Pl. Rar., 22. (1772) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 277. (1836) |
Web links |