Cyperus surinamensis |
Cyperus setigerus |
|
---|---|---|
tropical flatsedge |
lean flatsedge |
|
Habit | Herbs, annual or short-lived perennial, annuals cespitose; rhizomes absent. | Herbs, perennial, 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, 50–100 cm × 2.5–3 mm, glabrous. |
Leaves | 3–9, V-shaped, (12–)25–45(–65) cm × 2–10 mm; blades and bracts without cross ribs. |
V-shaped, 20–50 cm × 4–7 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 loosely ovoid, 1.5–7 cm wide; rays 5–13, 1–21 cm; 2d order rays 0.5–3 cm; bracts 3–8, V-shaped, 5–50 cm × 2.5–5.6 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. |
5–30, compressed, linear, (5–)12–40 × 1.5–2.2 mm; floral scales deciduous, 6–24, reddish brown to yellowish brown laterally, greenish medially, 5–7-ribbed, elliptic, 3–4 × 1.4–1.6 mm, apex obtuse. |
Flowers | stamen 1; anthers 0.5 mm; styles 0.8–1.1 mm; stigmas 0.5 mm. |
anthers 1.5–2 mm; styles 2–2.3 mm; stigmas 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. |
dark brown, sessile, oblong, 1.5 × 0.4–0.5 mm, apex apiculate, surfaces puncticulate. |
Cyperus surinamensis |
Cyperus setigerus |
|
Phenology | Fruiting late spring–early fall. | Fruiting summer. |
Habitat | Moist sunny areas with disturbed soils | Ditches, croplands |
Elevation | 0–200 m (0–700 ft) | 100–1000 m (300–3300 ft) |
Distribution |
AL; AR; FL; GA; KS; LA; MS; OK; SC; TN; TX; Mexico; Central America; South America
|
KS; MO; NM; OK; TX |
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. 170. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Name authority | Rottbøll: Descr. Pl. Rar., 20. (1772) | Torrey & Hooker: Ann. Lyceum Nat. Hist. New York 3: 434. (1836) |
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