Cyperus surinamensis |
Cyperus fuligineus |
|
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tropical flatsedge |
limestone flatsedge |
|
Habit | Herbs, annual or short-lived perennial, annuals cespitose; rhizomes absent. | Herbs, perennial, cespitose, rhizomatous. |
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, 7–30 cm × 0.5–1 mm, glabrous. |
Leaves | 3–9, V-shaped, (12–)25–45(–65) cm × 2–10 mm; blades and bracts without cross ribs. |
V-shaped to flat, 5–20 cm × 1–2.5 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. |
spike hemispheric, 7–20 mm wide; rays absent; rachis 1–3 mm; bracts 2–3, reflexed, flat, 5–12 cm × 1–2 mm; rachilla deciduous, wings 0.2 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. |
30–50, compressed, oblong-lanceoloid, 4–10 × 1.7–2.3 mm; floral scales deciduous, 5–12, dark reddish brown, laterally 3–5-ribbed, ovate, 1.5–2.2 × 1–1.6 mm, apex with mucro 0.1–0.2 mm. |
Flowers | stamen 1; anthers 0.5 mm; styles 0.8–1.1 mm; stigmas 0.5 mm. |
anthers 0.4–0.6 mm; styles 0.4–0.6 mm; stigmas 1–2 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. |
black, sessile, narrowly ellipsoid, 1–1.2 × 0.5–0.6 mm, apex obtuse, apiculate, glabrous, puncticulate, or papillose. |
Cyperus surinamensis |
Cyperus fuligineus |
|
Phenology | Fruiting late spring–early fall. | Fruiting spring–summer. |
Habitat | Moist sunny areas with disturbed soils | Coastal rocks, exposed limestone in hammocks and edges of mangrove swamps |
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
|
FL; West Indies |
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. 175. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Name authority | Rottbøll: Descr. Pl. Rar., 20. (1772) | Chapman: Fl. South. U.S., 511. (1860) |
Web links |