Cyperus aggregatus |
Cyperus elegans |
|
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ballast sedge, inflated-scale flatsedge |
royal flatsedge, sticky flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose, shortly rhizomatous, coarse, viscous. |
Culms | trigonous, 20–100 cm × 0.8–2.5 mm, glabrous. |
round to roundly trigonous, 15–80 cm × 2–4 mm, glabrous. |
Leaves | 5–10, V-shaped to flanged V-shaped, 10–70(–90) cm × 2–7 mm, margins and midribs scabridulous or glabrous. |
adaxial face concave, becoming trigonous apically, 15–75 cm × 1–4 mm, margins involute. |
Inflorescences | 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. |
spikes ovoid, 10–20 mm wide; rays 3–8(–10), 0.5–12 cm; 2d order rays 0–3, 1–3 cm; bracts 3–7, horizontal to vertical, 2.5–5.5 cm × 1–4 mm, margins involute; 2d order bracts 0–3, 1–3 cm; rachilla persistent, wingless. |
Spikelets | 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. |
3–20(–30), beige to greenish or reddish brown, strongly compressed, oblong-ellipsoid to oblong-lanceoloid, 3–15 × 2.5–3.5 mm; floral scales deciduous, 6–22, laterally pale greenish white to stramineous or reddish brown, medially pale green to yellowish green, laterally 2-ribbed, medially 3–5-ribbed, broadly ovate, (2–)2.8–3.6 × 2.4–2.6 mm, apex with slightly excurved mucro 0.2–0.3 mm, apically scabrid. |
Flowers | anthers 0.4–0.6 mm; styles 0.7–1.1 mm; stigmas 1.4–2.1 mm. |
anthers 0.6–1.4 mm; styles 1.2–1.5 mm; stigmas 1–1.5(–3) mm. |
Achenes | dark brown to reddish brown, sessile, broadly ellipsoid, 1.8–2.1 × 0.8–1 mm, apex apiculate, surfaces glabrous to finely puncticulate. |
dark reddish brown to black, stipitate, obovoid, faces concave, flat or subtly convex, (1.4–)1.8–2 × 0.9–1 mm, base cuneate, stipe (sometimes absent) spongy, 0.1–0.2 × 0.2–0.4 mm, apex truncate, apiculate, surfaces coarsely papillose. |
Cyperus aggregatus |
Cyperus elegans |
|
Phenology | Fruiting mid summer–fall (Jul–Oct). | Fruiting summer. |
Habitat | Dry roadsides, pastures, thickets | Ditches, damp pastures, pond shores, riverbanks |
Elevation | 0–500 m (0–1600 ft) | 0–500 m (0–1600 ft) |
Distribution |
AZ; LA; MS; NJ; NM; OR; PA; TX; Mexico; Central America; South America [Introduced, Australia]
|
FL; LA; NM; TX; Mexico; Central America; South America
|
Discussion | 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. | FNA vol. 23, p. 172. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
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 | C. trachynotus |
Name authority | (Willdenow) Endlicher: Cat. Horti Vindob. 1: 93. (1842) | Linnaeus: Sp. Pl. 1: 45. (1753) |
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