Cyperus involucratus |
Cyperus aggregatus |
|
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umbrella-plant |
ballast sedge, inflated-scale flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose, rhizomatous. |
Culms | trigonous, 30–150 cm × 1–5(–8) mm. |
trigonous, 20–100 cm × 0.8–2.5 mm, glabrous. |
Leaves | bladeless. |
5–10, V-shaped to flanged V-shaped, 10–70(–90) cm × 2–7 mm, margins and midribs scabridulous or glabrous. |
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 1(–6), densely cylindric, 6–30 × 5–11 mm; rays 3–12, 0.4–5(–7) cm; rays and rachis glabrous; usually only 1–2 spikes of inflorescence on elongate rays, other spikes sessile or nearly so; bracts 4–7, horizontal to slightly ascending, 1–16 cm × 0.5–4 mm; rachilla deciduous, wings persistent, 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. |
20–80, ellipsoid, roughly quadrangular, 3–5 × 1–1.4 mm; floral scales 1–2(–4), appressed, stramineous to golden brown, often red-speckled, medially greenish, 9-ribbed, elliptic to ovate, 2.4–3.4 × 1.8–2.6 mm, apex obtuse. |
Flowers | stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
anthers 0.4–0.6 mm; styles 0.7–1.1 mm; stigmas 1.4–2.1 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 to reddish brown, sessile, broadly ellipsoid, 1.8–2.1 × 0.8–1 mm, apex apiculate, surfaces glabrous to finely puncticulate. |
Cyperus involucratus |
Cyperus aggregatus |
|
Phenology | Fruiting early summer–fall. | Fruiting mid summer–fall (Jul–Oct). |
Habitat | Damp, disturbed soils, ditches, stream banks | Dry roadsides, pastures, thickets |
Elevation | 0–100(–800) m [0–300(–2600) ft] | 0–500 m [0–1600 ft] |
Distribution |
CA; FL; LA; TX; e Africa [Introduced in North America] |
AZ; LA; MS; NJ; NM; OR; PA; TX; Mexico; Central America; South America [Introduced, Australia]
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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.) |
The records of Cyperus aggregatus in New Jersey, Oregon, and Pennsylvania represent introductions from ballast. The closely related Mexican and Central American Cyperus regiomontanus Britton has been collected once as an adventive or waif in southern California. It is distinguished from C. aggregatus by its silvery green, subulate-lanceolate spikelets and achenes that are only 0.4–0.6 mm wide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 150. | FNA vol. 23. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Mariscus aggregatus, C. cayennensis, C. flavus, C. flavus var. aggregatus, C. flavus var. laevis, Kyllinga cayennensis, Kyllinga squarrosa, Mariscus flavus, Mariscus laevis | |
Name authority | Rottbøll: Descr. Pl. Rar., 22. (1772) | (Willdenow) Endlicher: Cat. Horti Vindob. 1: 93. (1842) |
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