Cyperus prolixus |
Cyperus houghtonii |
|
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mosquito flatsedge |
Houghton's flatsedge |
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Habit | Herbs, perennial; rhizomes 3–20 cm × 1–2 cm, indurate. | Herbs, perennial, cespitose, bases cormose, rhizomatous. |
Culms | stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous. |
trigonous, 5–50 cm × 0.5–1.5 mm, glabrous. |
Leaves | V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid. |
V-shaped, 12–30 cm × 1–6 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. |
spikes ± globose to broadly ovoid, 8–20 mm wide; rays 1–8 cm; rachis 2–5 mm, glabrous; bracts 3–8, weakly ascending, flat, 3–20 cm × 1–3.5 mm; rachilla deciduous, wingless. |
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. |
3–18, compressed, ovoid to oblong-lanceoloid, 4–15 × 2.6–3.4 mm; floral scales deciduous, 3–18, laterally stramineous to reddish brown, laterally 3–4-ribbed, broadly ovate, 1.8–2.5 × 1.3–1.6 mm, apex with mucro 0.1–0.2 mm. |
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 0.5–0.7 mm; styles 0.4–0.6 mm; stigmas 1–1.5 mm. |
Achenes | brown, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not apiculate, surfaces puncticulate. |
dark brown, sessile, broadly ellipsoid, 1.5–2 × 1–1.5 mm, apex obtuse, apiculate, surface glabrous, puncticulate, or papillose. |
2n | = 168, 170, 172. |
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Cyperus prolixus |
Cyperus houghtonii |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Coastal marshes | Riverbanks, sand bars, lakeshores, sand dunes, sandy openings in woods, especially among Jack pines |
Elevation | 0–10 m (0–0 ft) | 0–1100 m (0–3600 ft) |
Distribution |
LA; Mexico; Central America; South America |
IL; IN; MA; MD; ME; MI; MN; NH; NJ; NY; OH; PA; VA; VT; WI; WV; MB; ON; QC
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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.) |
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Source | FNA vol. 23, p. 167. | FNA vol. 23, p. 175. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. amplissimus | |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 206. (1816) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 277. (1836) |
Web links |