Cyperus involucratus |
Cyperus compressus |
|
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umbrella-plant |
annual sedge, poorland flatsedge |
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Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, annual, cespitose with fibrous roots. |
Culms | trigonous, 30–150 cm × 1–5(–8) mm. |
trigonous, (2–)6–15(–35) cm × (0.3–)1–1.8 mm, glabrous. |
Leaves | bladeless. |
1–5, flat to V-shaped, (1–)5–15(–22) cm × (0.5–)1.5–3 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 ± digitate, ± globose, 7–40 × 10–20 mm; rays (0–)1–6, 2–12 cm; if absent, inflorescence a sessile cluster of (1–)3–10 spikelets; rachis 2–5 mm; bracts (1–)4–5(–6), ascending, V-shaped, 1–15(–20) cm × 0.5–3.5 mm; rachilla persistent, 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. |
(1–)3–12(–16), greenish white, linear to linear-lanceoloid, compressed-quadrangular, 6–34(–40) × 2–3(–3.6) mm; floral scales deciduous, (8–)16–36(–42), spreading, laterally whitish, greenish, or pale brownish, medially green, weakly 7–9-ribbed, laterally weakly 1–2-ribbed, most ribs medial, ovate, (2.4–)2.6–3 × (1.9–)2–2.4(–2.5) mm, apex acute to ± acute, cuspidate tip (0.3–)0.5–0.7(–0.8) mm. |
Flowers | stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
anthers 0.6–0.7 mm; styles 0.9–1.3 mm; stigmas 0.5–0.8 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. |
brown, stipitate to sessile, obovoid, (1–)1.2–1.4(–1.5) × 0.9–1(–1.1) mm, apex obtuse to emarginate, surfaces very finely puncticulate. |
Cyperus involucratus |
Cyperus compressus |
|
Phenology | Fruiting early summer–fall. | Fruiting summer–early fall. |
Habitat | Damp, disturbed soils, ditches, stream banks | Various disturbed soils |
Elevation | 0–100(–800) m [0–300(–2600) ft] | 0–900 m [0–3000 ft] |
Distribution |
CA; FL; LA; TX; e Africa [Introduced in North America] |
AL; AR; DE; FL; GA; IL; LA; MD; MO; MS; NC; NY; OH; PA; SC; TX; VA; Mexico; Central America; South America; Asia; Africa
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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. 171. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. compressus var. pectiniformis, C. pectinatus, C. pectiniformis | |
Name authority | Rottbøll: Descr. Pl. Rar., 22. (1772) | Linnaeus: Sp. Pl. 1: 46. (1753) |
Web links |