Cyperus involucratus |
Cyperus granitophilus |
|
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umbrella-plant |
granite flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, annual, cespitose, with roots fibrous. |
Culms | trigonous, 30–150 cm × 1–5(–8) mm. |
trigonous, glabrous. |
Leaves | bladeless. |
V-shaped to flat, (2–)4–11 cm × 3–4 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. |
rays absent; bracts 2–4, ± horizontal, flat, 1–6.5 cm × 2–3 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. |
10–40, compressed, ovoid to linear-lanceoloid, quadrangular, 5–9 × 2–3 mm; floral scales deciduous, 5–20, spreading, pale greenish to reddish brown, laterally (5–)7–9(–13)-ribbed, ovate, 3–4 × 1–2 mm, apex straight, excurved mucronate, or cuspidate. |
Flowers | stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
stamens 1–2; filaments 1.5 mm; anthers 0.8–1 mm, connective apex reddish yellow, less than 0.1 mm; styles 0.8–1 mm; stigmas 1–1.2 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 to reddish brown, broadly ellipsoid to obovoid, 0.8–1.2 × 0.5–0.6 mm, base ± cuneate, apex truncate-obtuse, surfaces puncticulate. |
Cyperus involucratus |
Cyperus granitophilus |
|
Phenology | Fruiting early summer–fall. | Fruiting summer. |
Habitat | Damp, disturbed soils, ditches, stream banks | Thin soil over outcrops of granite or sandstone of the Piedmont and inner coastal plain |
Elevation | 0–100(–800) m [0–300(–2600) ft] | 50–400 m [160–1300 ft] |
Distribution |
CA; FL; LA; TX; e Africa [Introduced in North America] |
AL; GA; NC; SC; TN; VA
|
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.) |
Cyperus granitophilus is documented as an autotetraploid derivative of C. squarrosus (L. W. Garoni and W. H. Murdy 1964). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 150. | FNA vol. 23, p. 165. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rottbøll: Descr. Pl. Rar., 22. (1772) | McVaugh: Castanea 2: 103, figs. 4–8. (1937) |
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