Cyperus involucratus |
Cyperus refractus |
|
---|---|---|
umbrella-plant |
reflexed flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose, with inconspicuous, short rhizomes scarcely visible between culm bases. |
Culms | trigonous, 30–150 cm × 1–5(–8) mm. |
basally cormlike, trigonous, 30–100 cm × 2–4 mm, glabrous. |
Leaves | bladeless. |
V-shaped to flat, 20–70 cm × 3–8 mm, adaxial surface, margins minutely scabridulous. |
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 loose, broadly ellipsoid to ovoid, 4–7 × 2–6 cm; rays 6–13(–16), 4–25 cm, glabrous; rachis 1.5–3 cm; bracts 3–6, horizontal to ascending at 30°, flat, 5–35 cm × 2.5–6 mm; rachilla persistent, wings 0.4–0.5 mm wide. |
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. |
(13–)20–60(–74), linear, ± terete, (11–)13–25(–28) × 1.2–1.5 mm; distal spikelets spreading or ascending; floral scales persistent, (2–)3–6, stramineous, red-purple striate, laterally 3–5-ribbed, ovate-lanceolate, 4.5–5.3 × 1.2–1.5 mm. |
Flowers | stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
anthers 1–1.5 mm; styles 1.5 mm; stigmas 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. |
brown to purplish brown, oblong-linear (5–6 times long as wide), 2.6–3 × 0.5–0.6 mm, base cuneate, apex obtuse, surfaces puncticulate. |
Cyperus involucratus |
Cyperus refractus |
|
Phenology | Fruiting early summer–fall. | Fruiting summer (Jul–Aug). |
Habitat | Damp, disturbed soils, ditches, stream banks | Sandy riverbanks, gravelly roadsides, pastures, disturbed places |
Elevation | 0–100(–800) m [0–300(–2600) ft] | 20–300 m [70–1000 ft] |
Distribution |
CA; FL; LA; TX; e Africa [Introduced in North America] |
AL; AR; DC; GA; MD; MO; NC; PA; SC; TN; VA; WV |
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 refractus is often mistaken for C. strigosus, which has shorter anthers (0.4–0.5 mm) and spreading, ± deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 150. | FNA vol. 23, p. 182. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rottbøll: Descr. Pl. Rar., 22. (1772) | Engelmann ex Boeckeler: Linnaea 36: 369. 1870, based on Cyperus refrofractus Engelmann ex Steudel, Syn. Pl. Glumac. 2: 47. 1855, not (Linnaeus) Torrey (1848) |
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