Cyperus prolixus |
Cyperus ochraceus |
|
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mosquito flatsedge |
pond flatsedge |
|
Habit | Herbs, perennial; rhizomes 3–20 cm × 1–2 cm, indurate. | Herbs, perennial, cespitose; rhizomes oblique. |
Culms | stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous. |
roundly trigonous, 20–50(–80) cm × 1–3 mm, glabrous. |
Leaves | V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid. |
3–11, V-shaped, 12–40 cm. |
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 loosely to rather densely hemispheric, 15–30 mm diam.; rays 5–10, 2–12 cm; 2d order rays occasionally produced, 5–25 mm; bracts 4–8, approximately horizontal to ascending at 30°, V-shaped, 10–36 cm × 1.5–4 mm, margins glabrous. |
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. |
(4–)10–30, greenish, grayish, or stramineous, oblong to linear-oblong, compressed, (5–)7–10(–35) × 2–3 mm; floral scales 10–25(–85), laterally yellowish brown, medially yellowish or brownish, laterally ribless, medially 2-ribbed with groove between ribs, broadly ovate (widest in proximal 1/2), (1.2–)1.5–2 × 1.2–2 mm, apex obtuse (declined (45–)60–90º from rachilla). |
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 oblong, 0.8–1.2 mm, connective not prolonged; styles basally thickened, confluent with summit of achene, 0.6–1.2 mm; stigmas 0.3–0.6 mm. |
Achenes | brown, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not apiculate, surfaces puncticulate. |
reddish brown to dark purplish brown, dull or more often iridescent, stipitate, broadly ellipsoid, 1–1.5 mm × 0.4–0.6(–0.7) mm, base cuneate to ± attenuate, stipe 0.1–0.2 mm, apex acute, beak 0.1–0.5 mm, surfaces reticulate with network of low ridges. |
Cyperus prolixus |
Cyperus ochraceus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Coastal marshes | Damp, disturbed soils, ditches, marshes |
Elevation | 0–10 m [0–30 ft] | 0–200 m [0–700 ft] |
Distribution |
LA; Mexico; Central America; South America |
FL; GA; LA; MS; PA; TX; Mexico; Central America; South America
|
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.) |
In Pennsylvania, Cyperus ochraceus has been recorded in areas where ballast has been discarded. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 167. | FNA vol. 23, p. 155. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. amplissimus | |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 206. (1816) | Vahl: Enum. Pl. 2: 325. (1805) |
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