Cyperus surinamensis |
Cyperus planifolius |
|
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tropical flatsedge |
flatleaf flatsedge |
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Habit | Herbs, annual or short-lived perennial, annuals cespitose; rhizomes absent. | |
Culms | 2–6, trigonous, (10–)35–80 cm × 0.5–2(–4) mm, scabridulous with retrorse prickles (infrequently glabrous or rarely also with extrorse prickles). |
trigonous, 25–50(–80) cm × 0.8–2.6 mm, glabrous. |
Leaves | 3–9, V-shaped, (12–)25–45(–65) cm × 2–10 mm; blades and bracts without cross ribs. |
flat to V-shaped, 30–80 cm × 3–10 mm. |
Inflorescences | heads umbellate, 10–20(–30) mm diam.; rays 4–12, 1–6 cm, minutely scabridulous with retrorse prickles; 2d order rays often present, 1–2(–3) cm; 3d order rays rarely present, 0.5–1.5 cm; bracts 3–8, approximately horizontal to ascending at 30°, V-shaped to flat, 2–15(–34) cm × 1–4(–5) mm. |
spikes ovoid, 1.5–3 × 1.5–3 cm; rays 4–7, 1–10 cm; 2d order rays occasionally present, 0.5–2 cm, rays often not elongate, inflorescence then capitate, 2–5 cm diam.; bracts 4–8, horizontal to ascending at 30°, flat to V-shaped, longest 6–35 cm × (1.5–)4–8 mm; rachilla persistent, wings 0.4–0.6 mm wide. |
Spikelets | (6–)15–40(–65), greenish white, linear to linear-oblong, (3–)4–12(–15) × 1.5–2.5 mm; floral scales 10–50(–65), laterally pale yellow, light brown, or reddish brown, 2-keeled, medially 3-ribbed, lanceolate, 1–1.5 × 0.8–0.9 mm, distinctly reticulate, often scabridulous near apex. |
(10–)20–60, reddish brown, flattened elliptic in cross section, linear-lanceoloid, 6–22 cm × (1–)2–3(–4) mm; floral scales deciduous, 6–16, medially greenish, laterally reddish brown to brown, medially 3–5-ribbed, laterally 3–5-ribbed, ovate-lanceolate to ± orbiculate, 2.5–3 × 1.4–1.8 mm, apex acute to obtuse and mucronulate. |
Flowers | stamen 1; anthers 0.5 mm; styles 0.8–1.1 mm; stigmas 0.5 mm. |
anthers 0.7–1.8 mm; styles (0.3–)1.2–2.8 cm; stigmas (1–)2–3 mm. |
Achenes | brown to reddish brown, slightly stipitate, narrowly ellipsoid, 0.7–0.9 × 0.2–0.4 mm, apex apiculate, surfaces papillate or obscurely reticulate to rugulose. |
brownish to black, stipitate or sessile, ellipsoid to obovoid or oblong, 1.3–2 × 0.75–1(–1.1) mm, apex obtuse, apiculate or not, surfaces coarsely punctate. |
Herb | , perennial, cespitose, rhizomatous. |
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Cyperus surinamensis |
Cyperus planifolius |
|
Phenology | Fruiting late spring–early fall. | Fruiting throughout the year. |
Habitat | Moist sunny areas with disturbed soils | Coral sand beaches, coastal rock outcrops |
Elevation | 0–200 m (0–700 ft) | 0–10 m (0–0 ft) |
Distribution |
AL; AR; FL; GA; KS; LA; MS; OK; SC; TN; TX; Mexico; Central America; South America
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FL; GA; Mexico; West Indies; Central America (Belize, Honduras) |
Discussion | Cyperus surinamensis is distinguished readily from all other species of the genus in the New World by the usual presence of retrorse prickles on the culms and rays. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 23, p. 153. | FNA vol. 23, p. 172. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. brizaeus, C. brunneus, C. purpurascens | |
Name authority | Rottbøll: Descr. Pl. Rar., 20. (1772) | Richard: Actes Soc. Hist. Nat. Paris 1: 106. (1792) |
Web links |