Cyperus hermaphroditus |
Cyperus eragrostis |
|
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hermaphrodite flatsedge |
tall cyperus, tall flatsedge, tall nutgrass |
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Habit | Herbs, perennial, rhizomatous. | Herbs, perennial, cespitose, rhizomatous. |
Culms | trigonous, (10–)30–80(–140) cm × (0.4–)1–3(–5) mm, glabrous. |
trigonous to terete, (25–)40–60(–90) cm, glabrous. |
Leaves | V-shaped or flanged V-shaped, (5–)15–70(–90) cm × (2–)4–10(–13) mm, glabrous. |
flat or V-shaped, (10–)25–50 cm × 5–8(–12) mm. |
Inflorescences | spikes 1(–5), rather densely ovoid or oblong-cylindric, (10–)25–45(–62) × 7–22 mm, 11–21 spikelets per 5 mm of rachis; rays (3–)5–10(–17), (1–)5–12(–24) cm; bracts (2–)4–8, ascending at 30–45°, V- or inversely W-shaped, (2–)8–40(–65) cm × (1–)2–8 mm; rachilla deciduous, wings 0.4–0.5 mm wide. |
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 | (10–)50–150, oblong to linear, quadrangular, (3–)4–8(–18) × (0.8–)1–1.2(–1.6) mm; distal spikelet spreading or ascending; floral scales (1–) 3–8, pale greenish white to golden brown, deep brown, or reddish brown, medially usually green, weakly to strongly 3(–4)-ribbed laterally, 1–3-ribbed medially, ovate to elliptic, (2–)2.6–3.2(–4) × 1.2–2 mm, apex obtuse. |
(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 (0.4–)0.6–1 mm; styles 0.4–1.6 mm; stigmas 1–1.5 mm. |
stamen 1; anthers 1–1.2 mm; styles 1–1.2 mm; stigmas 0.5 mm. |
Achenes | brown or reddish brown, sessile or nearly so, ellipsoid, 1.4–1.8(–2) × 0.6–0.8(–1) mm, apex acute to obtuse, slightly apiculate, surfaces puncticulate. |
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 hermaphroditus |
Cyperus eragrostis |
|
Phenology | Fruiting summer–fall. | Fruiting summer. |
Habitat | Arroyos | Damp grasslands, roadsides ditches |
Elevation | 500–1200 m (1600–3900 ft) | 0–200 m (0–700 ft) |
Distribution |
AZ; TX; Mexico; South America; West Indies |
AL; CA; LA; MS; NJ; OR; PA; SC; TX; WA; BC; South America; naturalized; Europe
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Discussion | An erroneous report of Cyperus hermaphroditus from Alabama was based on misidentification of C. thyrsiflorus. (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. 186. | FNA vol. 23, p. 154. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | Carex hermaphrodita, Mariscus hermaphroditus, Mariscus jacquinii | C. vegetus |
Name authority | (Jacquin) Standley: Contr. U.S. Natl. Herb. 18: 88. (1916) | Lamarck: in J. Lamarck and J. Poiret, Tabl. Encycl. 1: 146. (1791) |
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