Cyperus alopecuroides |
Cyperus amabilis |
|
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foxtail flatsedge |
foothill flatsedge |
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Habit | Herbs, perennial, rhizomatous, coarse. | Herbs, annual, cespitose. |
Culms | trigonous, 150–250 cm × 2–15 mm, glabrous. |
1–10(–25), roundly trigonous, 3–12 cm × 0.3–0.8 mm, glabrous. |
Leaves | inversely W-shaped, 30–150 cm × 6–22 mm. |
1–3–(4), 1–6 cm × 1(–1.5) mm. |
Inflorescences | spikes 1–4, cylindric, 1.5–4 cm × 7–15 mm; rays 3–9, 10–26 cm; 2d order rays 2–11 cm; 3d order rays 1–4 cm (or absent); bracts 3–5, ± horizontal, 20–100 cm × 3–15 mm; 2d order bracts 2–7 cm × 2–7 mm; 3d order bracts 2–5 cm × 2–4 mm (or absent); rachilla persistent, wingless or wing hyaline, narrow, 0.1 mm wide. |
if rays absent heads single, dense, sessile, digitate, 5–20 × 10–30 mm, single heads 10–30(–50) mm; rays usually absent, if present 1–8 cm; 2d order rays infrequently present, 1–2 cm; bracts 3–6, erect to oblique, flat to V-shaped,(0.5–)2–10(–15) cm × 0.5–2 mm. |
Spikelets | 50–100, linear, ± quadrangular, slightly compressed, 8–11 × 0.9–1.2 mm; floral scales 15–30, marginally clear, laterally reddish along midrib, medially green, laterally 3–4 ribbed, medially 3–5-ribbed, ovate, 1–2–1.6 × 1.1–1.3 mm, apex mucronulate. |
5–10(–20), linear to linear-lanceoloid, (5–)8–12(–35) × 1.6–2.3(–2.5) mm; floral scales (6–)16–30(–76), laterally glossy reddish brown to brown, medially greenish, sometimes also reddish or brownish, laterally ribless, medially strongly 3-ribbed, ovate-lanceolate, 1.9–2(–2.3) mm (including prominent excurved cusp of 0.3–0.5 mm) × 0.8–1.1 mm, apex truncate, emarginate, or cuspidate. |
Flowers | anthers 2, 0.4–0.5 mm; styles 0.8–1 mm; stigmas 2, 0.4 mm. |
stamens (1–)2–3; anthers ellipsoid, 0.3 mm, connectives not prolonged; styles 0.3–0.4 mm; stigmas 0.4–0.7 mm. |
Achenes | dark brown, sessile, ellipsoid to obovoid, 0.9 × 0.4–0.5 mm, surfaces finely puncticulate. |
brown, slightly stipitate, obovoid to oblong, 0.8–0.9 × 0.4–0.5 mm, apex abruptly apiculate, surfaces papillose. |
Cyperus alopecuroides |
Cyperus amabilis |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Pond shores, stream banks | Seasonally wet, sandy soils |
Elevation | 0–30 m (0–100 ft) | 500 m (1600 ft) |
Distribution |
FL; West Indies; Asia; Africa; Australia [Introduced in North America] |
AZ; Mexico; Central America; South America; Asia; Africa |
Discussion | Cyperus alopecuroides has been introduced in Polk County, Florida. Plants of Cyperus alopecuroides might be confused with C. digitatus; large size and the biconvex achenes with two stigmas characterize C. alopecuroides. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 173. | FNA vol. 23, p. 158. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. amabilis var. macrostachyus, C. aurantiacus, C. aureus, C. aureus var. aurantiacus, C. aureus var. macrostachyus, C. aureus var. oligostachyus, C. microstachyus, C. oligostachyus | |
Name authority | Rottbøll: Descr. Pl. Rar., 20. (1772) | Vahl: Enum. Pl. 2: 318. (1805) |
Web links |