Cyperus giganteus |
Cyperus eragrostis |
|
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giant flatsedge, Mexican papyrus |
tall cyperus, tall flatsedge, tall nutgrass |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, perennial, cespitose, rhizomatous. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
trigonous to terete, (25–)40–60(–90) cm, glabrous. |
Leaves | bladeless. |
flat or V-shaped, (10–)25–50 cm × 5–8(–12) mm. |
Inflorescences | spikes loosely cylindric, 15–40 × 8–16 mm; rays 5–8, ascending to erect, stiff,20–30 cm; 2d order rays 5–15 cm; bracts 10–12, ascending at 30–60°, flat, (8–) 20–45 cm × 4–12 mm; 2d order bracts (5–)15–25 cm × 1.5–5 mm; rachilla persistent, separating laterally, remaining firmly attached basally, wings 0.3–0.4 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 | (15–)50–80, slightly compressed, linear, ± quadrangular, 5–12 × 0.6–1.4 mm; floral scales 8–20, appressed, reddish beside 5-ribbed green medial part, white to hyaline near margins, ovate, 1.8–2.2 × 1.2–1.5 mm, apex acute to 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 0.7–1 mm (connective prolonged beyond anther as red subulate appendage 0.2–0.5 mm, its apex sometimes setose); styles 0.2–0.5 mm; stigmas (0.8–)1.2–1.8 mm. |
stamen 1; anthers 1–1.2 mm; styles 1–1.2 mm; stigmas 0.5 mm. |
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely 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 giganteus |
Cyperus eragrostis |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, marshes | Damp grasslands, roadsides ditches |
Elevation | 0–10 m (0–0 ft) | 0–200 m (0–700 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
AL; CA; LA; MS; NJ; OR; PA; SC; TX; WA; BC; South America; naturalized; Europe
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Discussion | Cyperus giganteus was erroneously reported from Florida, a misidentification of C. papyrus (R. R. Haynes and A. Lasseigne 1969). Recently, some nurseries specializing in water plants have begun to offer C. giganteus under the name “Mexican papyrus.” Escaped cultivated plants may be expected in southeastern and southwestern United States. (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. 173. | FNA vol. 23, p. 154. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | C. vegetus | |
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Lamarck: in J. Lamarck and J. Poiret, Tabl. Encycl. 1: 146. (1791) |
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