Cyperus oxylepis |
Cyperus eragrostis |
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sharpscale flatsedge |
tall cyperus, tall flatsedge, tall nutgrass |
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Habit | Herbs, perennial, cespitose, coarse, (culms, leaves, bracts, and rays viscid). | Herbs, perennial, cespitose, rhizomatous. |
Culms | roundly trigonous, 10–50 cm × 0.9–2.4 mm. |
trigonous to terete, (25–)40–60(–90) cm, glabrous. |
Leaves | adaxial face concave, becoming flat to trigonous apically, 10–46 cm × 1.5–4 mm, margins involute. |
flat or V-shaped, (10–)25–50 cm × 5–8(–12) mm. |
Inflorescences | spikes ovoid, 1–5.5 cm wide; rays usually 3–6, 0.5–5 cm, glabrous; sometimes absent in small plants; if absent, inflorescence a congested head of spikelets 1–3.5 cm diam.; 2d order rays 0–3, 1–3 cm; bracts 3–5, vertical to ascending at 45°, 2.5–25 cm × 1.2–4 mm, margins involute; 2d order bracts 0–2, 5–20 mm; rachilla persistent, wingless. |
heads globose, (10–)20–40 mm diam.; rays (0–)3–10, 2.5–5(–12) cm; 2d order rays usually absent (when present, 0.5–1.5 cm); bracts 4–8, horizontal to ascending at 15–30°, flat (or V-shaped), 3–30(–50) cm × 1.5–8(–12) mm. |
Spikelets | 5–24, greenish yellow to golden brown, oblong to linear-lanceoloid, quadrangular, strongly compressed, 7–20(–30) × 2.5–4(–6) mm; floral scales 10–20(–40), spreading, pale green to stramineous, laterally 2–3-ribbed, ovate-lanceolate, 3.1–4 × 1.5–2.4 mm, apex with mucro 0.2–0.8 mm. |
(20–)30–50(–70), oblong, compressed, 5–20 × 2.2–3 mm; floral scales (12–)20–30(–50), off-white to golden brown, basally 2-keeled, laterally ribless, ovate-deltate, 2–2.3 × 1–1.4 mm (declined 30–40º from rachilla). |
Flowers | anthers 0.6–0.8 mm; styles 0.8–1.6 mm; stigmas 1–1.4 mm. |
stamen 1; anthers 1–1.2 mm; styles 1–1.2 mm; stigmas 0.5 mm. |
Achenes | light to dark brown, rarely somewhat reddish, stipitate, ellipsoid, 2–2.4 × 0.5–0.8 mm, base cuneate, stipe whitish, spongy, 0.2–0.3 × 0.2–0.4 mm, apex acute, persistent style forming beak 0.5–1.2 mm, surfaces glabrous or finely papillose. |
black or dark brown, stipitate, broadly ellipsoid, 1.2–1.4 × 0.5–0.6 mm, stipe to 0.1 mm, apex apiculate, beak 0.2–0.3 mm, surfaces puncticulate. |
Cyperus oxylepis |
Cyperus eragrostis |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Ditches and disturbed places in marshes, often in saline soil | Damp grasslands, roadsides ditches |
Elevation | 0–100 m (0–300 ft) | 0–200 m (0–700 ft) |
Distribution |
AR; FL; GA; LA; MS; SC; TX; Mexico; South America [Introduced in North America]
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AL; CA; LA; MS; NJ; OR; PA; SC; TX; WA; BC; South America; naturalized; Europe
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Discussion | Cyperus oxylepis is easily recognized by its sticky leaves, culms, and bracts (in living plants), involute leaves,and golden brown spikelets. The ovate-lanceolate floral scales and the ellipsoid, brownish achene with a persistent beak distinguish C. oxylepis from other species with deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The distributions of Cyperus eragrostis in British Columbia, Alabama, Pennsylvania, South Carolina, and Texas represent introduced populations. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 171. | FNA vol. 23, p. 154. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | C. vegetus | |
Name authority | Nees ex Steudel: Syn. Pl. Glumac. 2: 25. (1855) | Lamarck: in J. Lamarck and J. Poiret, Tabl. Encycl. 1: 146. (1791) |
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