Cyperus prolixus |
Cyperus acuminatus |
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mosquito flatsedge |
pale umbrella-sedge, sharp-point flatsedge, short flatsedge, short point cyperus, taper-tip cyperus, taper-tip flat sedge |
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Habit | Herbs, perennial; rhizomes 3–20 cm × 1–2 cm, indurate. | Herbs, annual, cespitose. |
Culms | stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous. |
roundly trigonous, (10–)20–30(–45) cm × 0.4–1.2 mm, distal 1/2 glabrous or infrequently scabridulous. |
Leaves | V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid. |
2–6(–8), V-shaped or flat, 8–12(–16) cm × 1–2(–4) mm. |
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. |
heads hemispheric, 7–12(–15) mm diam.; rays 1–3(–5), 0.5–2 cm; bracts 3–6, longest erect to ascending, flat to V-shaped, (1.5–)3–12(–25) cm × 1–2.5(–3.5) mm. |
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. |
(15–)25–50(–75), ovoid, compressed, 4–7 × 2–3 mm; floral scales 8–20(–35), laterally yellowish, yellowish green, or light reddish brown, medially light brown or greenish brown, 2-keeled, subtly 1-ribbed, ovate-lanceolate, 1–2 × 1–1.4 mm, apex acute, mucronate, straight to excurved, glabrous or sparsely scabridulous. |
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. |
stamen 1; anthers 0.5 mm; styles 0.8–1.1 mm; stigmas 0.5 mm. |
Achenes | brown, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not apiculate, surfaces puncticulate. |
brown, stipitate, broadly ellipsoid, abruptly contracted to base, 0.8–1.1 × 0.3–0.4 mm, stipe 0.1 mm, apex acute, tapering to slender beak formed of persistent style base, surfaces papillose. |
Cyperus prolixus |
Cyperus acuminatus |
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Phenology | Fruiting summer. | Fruiting summer–fall (Jul–Oct). |
Habitat | Coastal marshes | Wet, often sandy shores and damp, disturbed soils |
Elevation | 0–10 m [0–30 ft] | 0–1500 m [0–4900 ft] |
Distribution |
LA; Mexico; Central America; South America |
Mexico (Coahuila, Tamaulipas) [Ala., Ariz., Ark., Calif., Colo., Ill., Ind., Iowa, Kans., Ky., La., Mich., Minn., Mo., Mont., Nebr., N.H., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa. (introduced?), S.Dak., Tenn., Tex., Utah, Va., Wash., Wyo.]
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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.) |
Cyperus acuminatus may be introduced in New Hampshire and New York. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 167. | FNA vol. 23, p. 152. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. amplissimus | C. acuminatus var. cyrtolepis, C. cyrtolepis, C. cyrtolepis var. denticarinatus, C. rufescens var. denticarinatus |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 206. (1816) | Torrey & Hooker: Ann. Lyceum Nat. Hist. New York 3: 435. (1836) |
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