Cyperus prolixus |
Cyperus aggregatus |
|
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mosquito flatsedge |
ballast sedge, inflated-scale flatsedge |
|
Habit | Herbs, perennial; rhizomes 3–20 cm × 1–2 cm, indurate. | Herbs, perennial, cespitose, rhizomatous. |
Culms | stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous. |
trigonous, 20–100 cm × 0.8–2.5 mm, glabrous. |
Leaves | V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid. |
5–10, V-shaped to flanged V-shaped, 10–70(–90) cm × 2–7 mm, margins and midribs scabridulous or glabrous. |
Inflorescences | spikes appressed-ascending, narrowly cylindric, (2–)3–45 mm × (4–)7–10 mm; rays (5–)9–12, 2–22(–30) cm; 2d order rays distinctly flattened, 1–10 cm; 3d order rays flattened, 0.5–3 cm; rachis 2.5–4 cm; bracts (6–)9–10, ascending at 45–75°, V- or inversely W-shaped, (5–)15–90 cm × 0.5–20 mm; rachilla persistent, wings 0.2–0.4 mm wide. |
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 | (4–)10–35, appressed-ascending, compressed, linear, 7–12(–15) × 0.6–1.2 mm; floral scales deciduous, 6–20, marginally clear, laterally brown, medially green, laterally 2–3-ribbed, medially 1-ribbed, oblong-ovate, (3.2–) 3.8–4.3 × 1.2–1.7 mm, apex spreading, acute to obtuse, mucronulate. |
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 | anthers 0.7–0.9 mm, connective apex bright red, oblong, to 0.1 mm; styles 0.8–1.3 mm; stigmas 2–3.3 mm. |
anthers 0.4–0.6 mm; styles 0.7–1.1 mm; stigmas 1.4–2.1 mm. |
Achenes | brown, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not 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 prolixus |
Cyperus aggregatus |
|
Phenology | Fruiting summer. | Fruiting mid summer–fall (Jul–Oct). |
Habitat | Coastal marshes | Dry roadsides, pastures, thickets |
Elevation | 0–10 m [0–30 ft] | 0–500 m [0–1600 ft] |
Distribution |
LA; Mexico; Central America; South America |
AZ; LA; MS; NJ; NM; OR; PA; TX; Mexico; Central America; South America [Introduced, Australia]
|
Discussion | Cyperus prolixus produces large plants, similar in habit to C. giganteus and C. papyrus but easily distinguished by flattened rays. (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. 167. | FNA vol. 23. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. amplissimus | Mariscus aggregatus, C. cayennensis, C. flavus, C. flavus var. aggregatus, C. flavus var. laevis, Kyllinga cayennensis, Kyllinga squarrosa, Mariscus flavus, Mariscus laevis |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 206. (1816) | (Willdenow) Endlicher: Cat. Horti Vindob. 1: 93. (1842) |
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