Cyperus erythrorhizos |
Cyperus papyrus |
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red-root cyperus, red-root flat sedge, redroot nutgrass |
Egyptian paper-reed, papyrus |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, rhizomatous, stout. |
Culms | trigonous to roundly trigonous, (0.5–)5–25(–105) cm × 1–2.5(–7.5) mm, glabrous. |
roundly trigonous, 300–500 cm × 15–45 mm, glabrous. |
Leaves | flat to inversely W-shaped, 5–25(–90) cm × 2–5(–11) mm. |
bladeless. |
Inflorescences | spikes 1–3(–6), rather densely cylindric-ovoid, (4–)10–30(–45) × (6–)10–16(–23) mm; rays 2–6(–12), 1–8(–28) cm; bracts (3–)5–7(–11), horizontal to ascending at 30°, inversely W-shaped, (3–)10–20(–70) cm × 1–3(–12) mm; rachilla persistent, at maturity becoming laterally free, remaining firmly attached proximally, wings 0.3(–0.4) mm wide. |
spikes loosely cylindric, 10–20 × 6–10 mm; rays 40–100, drooping or arching, slender, 10–30 cm; 2d order rays 8–20 cm; bracts 4–10, ± erect, V-shaped, 3–8 cm × 4–15 mm; 2d order bracts 2–5, (1.5–)4–16 cm × 0.5–2 mm; rachilla persistent, separating laterally, remaining firmly attached basally, wings 0.3–0.4 mm wide. |
Spikelets | (20–)40–80, linear, quadrangular, 3–8(–11) × 1–1.5 mm; floral scales deciduous, 6–16(–30), appressed, laterally light brown with reddish speckles, medially greenish, laterally ribless, medially 3-ribbed, oblong-ovate to obovate, quadrangular to subterete, 1.3–1.5 × 0.8–1.2 mm, apex obtuse, mucronulate. |
6–30, slightly compressed, linear, ± quadrangular, 6–10 × 0.8–1 mm; floral scales 6–16, reddish beside 5-ribbed green medial part, white to hyaline near margins, ovate-elliptic, 1.8–2.2 × 1.2–1.5 mm, apex acute to obtuse. |
Flowers | anthers 0.2–0.3 mm, connectives 0.1 mm; styles 0.7–0.8 mm; stigmas 0.4 mm. |
anthers 0.8–1 mm (connectives prolonged beyond anther as red subulate appendage 0.2–0.5 mm, apex usually setose); styles 0.2–0.4 mm; stigmas 0.8–1.2 mm. |
Achenes | light grayish to brown, sessile, ovoid, (0.4–)0.7–1 × 0.4–0.6 mm, apex rounded, apiculate, surfaces glabrous. |
pale brown, sessile, oblong, 0.8–1 × 0.4 mm, apex scarcely apiculate, surfaces puncticulate. |
Cyperus erythrorhizos |
Cyperus papyrus |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Emergent shorelines | Stream banks, marshes |
Elevation | 0–1500 m (0–4900 ft) | 0–30 m (0–100 ft) |
Distribution |
AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; WA; WI; WV; MB; ON; Mexico (Baja California)
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FL; s Europe; sw Asia; Africa [Introduced in North America] |
Discussion | Cyperus papyrus is conspicuous in the field by its great height, leafless culm, and open, hemispheric inflorescence with drooping rays. Ancient Egyptians, Greeks, and Romans prepared paper from the pith of the culms of Cyperus papyrus, which is abundant along the Nile River. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 172. | FNA vol. 23, p. 173. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. cupreus, C. erythrorhizos var. cupreus, C. occidentalis, C. washingtonensis | |
Name authority | Muhlenberg: Descr. Gram., 20. (1817) | Linnaeus: Sp. Pl. 1: 47. (1753) |
Web links |
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