Cyperus prolixus |
Cyperus retrofractus |
|
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mosquito flatsedge |
rough flatsedge |
|
Habit | Herbs, perennial; rhizomes 3–20 cm × 1–2 cm, indurate. | Herbs, perennial, cespitose. |
Culms | stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous. |
with cormlike bases, sharply trigonous, 25–90 cm, glabrous proximally, minutely scabridulous distally. |
Leaves | V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid. |
V-shaped, 14–40 cm × 3.5–8 mm, (pubescent on adaxial side of midrib). |
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 loose, obtrulloid to obdeltoid (broadest near apex, nearly as long as wide), 20–28(–34) × (12–)15–30 mm; rays 4–13, (1–)4–24 cm (longest ray shorter than bracts), glabrous; bracts 3–12, ascending at 30–45°, flat, 3–25 cm × 3–7 mm; rachilla persistent, wings 0.4–0.6 mm wide, covering 3/4 of mature achene. |
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. |
30–50, proximal one reflexed, distal ones divaricate, linear-lanceoloid, ± terete, (6.5–) 8–10(–17) × 0.5–0.7 mm; floral scales persistent, 3–6(–8), appressed, stramineous (suffused with reddish purple), 4–5-ribbed laterally, ovate-lanceolate, (4–)4.4–4.9(–5.4) × 1.3–1.5 mm; terminal scale not spinose, apex straight, excurved mucronate, or cuspidate. |
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 0.7–1.2 mm; styles 1.5–2 mm; stigmas 2–2.5 mm. |
Achenes | brown, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not apiculate, surfaces puncticulate. |
brown to brownish black, narrowly oblong, (2.2–)2.5–3 × 0.6–0.7 mm, base cuneate, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus prolixus |
Cyperus retrofractus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Coastal marshes | Roadsides, pastures, disturbed sites in sandy or clayey soils |
Elevation | 0–10 m [0–30 ft] | 0–300 m [0–1000 ft] |
Distribution |
LA; Mexico; Central America; South America |
AL; AR; DC; DE; GA; KY; MO; NC; NJ; OH; PA; SC; TN; VA
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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.) |
For information concerning nomenclature of Cyperus retrofractus, see J. R. Carter and C. E. Jarvis (1986). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 167. | FNA vol. 23, p. 180. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. amplissimus | Scirpus retrofractus, C. dipsaciformis, C. retrofractus var. dipsaciformis, Mariscus retrofractus |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 206. (1816) | (Linnaeus) Torrey: in J. Carey, Carices North. U.S., 519. (1847) |
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