Cyperus surinamensis |
Cyperus sphacelatus |
|
---|---|---|
tropical flatsedge |
roadside flatsedge |
|
Habit | Herbs, annual or short-lived perennial, annuals cespitose; rhizomes absent. | Herbs, annual or perennial, cespitose. |
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, 15–60 cm × 1–3 mm, glabrous. |
Leaves | 3–9, V-shaped, (12–)25–45(–65) cm × 2–10 mm; blades and bracts without cross ribs. |
2–6, flat to V-shaped, 6–30(–40) cm × 2–4 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 broadly ellipsoid, 5–45 × 10–30(–45) mm; rays (2–)5–9, (0.3–)3–10 cm; rachis 4–17 mm; bracts 5–6, horizontal to ascending, V-shaped, 1.5–30 cm × 0.5–4 mm; rachilla persistent, wings hyaline, 0.4–0.5 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, pale greenish white or stramineous, compressed, linear-lanceoloid, 7–35 × (1.2–)1.4–2 mm; floral scales deciduous, 6–34, spreading or appressed, laterally greenish white, often reddish or brown speckled, medially green, laterally 3–5-ribbed, medially 3-ribbed, elliptic, (2.2–)3–4(–4.4) × (1.2–)1.8–2.2 mm, apex acute. |
Flowers | stamen 1; anthers 0.5 mm; styles 0.8–1.1 mm; stigmas 0.5 mm. |
anthers 0.6 mm; styles 0.6–1.2 mm; stigmas 1–1.4(–1.7) 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. |
reddish brown to dark brown, stipitate, narrowly ellipsoid, 1.4–2 × 0.6–0.9 mm, apex apiculate, surfaces puncticulate. |
Cyperus surinamensis |
Cyperus sphacelatus |
|
Phenology | Fruiting late spring–early fall. | Fruiting summer. |
Habitat | Moist sunny areas with disturbed soils | Disturbed, wet soils |
Elevation | 0–200 m (0–700 ft) | 0 m (0 ft) |
Distribution |
AL; AR; FL; GA; KS; LA; MS; OK; SC; TN; TX; Mexico; Central America; South America
|
FL; Central America; South America; West Indies; Africa [Introduced in North America] |
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 | ||
Synonyms | C. balbisii | |
Name authority | Rottbøll: Descr. Pl. Rar., 20. (1772) | Rottbøll: Descr. Pl. Rar., 21. (1772) |
Web links |