Cyperus giganteus |
Cyperus dentatus |
|
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giant flatsedge, Mexican papyrus |
tooth flatsedge |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, perennial, cespitose, rhizomatous; stolons tuberiferous, 1–10 cm. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
trigonous, 8–50 cm × 1–3 mm. |
Leaves | bladeless. |
flat or V-shaped, 10–40 cm × 2–5 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 digitate, 8–18 mm diam.; rays 4–9, 1–8 cm; 2d order rays 0.5–2 cm; bracts 3–5, ± horizontal, flat, 1–20 cm × 1–4 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. |
commonly proliferous, 2–6, linear to oblong, compressed, 3–24 × 2–2.5 mm; floral scales 3–20(–50), reddish brown, laterally 1–3-ribbed, ovate, 2–2.5 × 1.5–2 mm. |
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. |
stamens 3; anthers 1.5 mm; styles 1 mm; stigmas 1.5 mm. |
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
reddish brown, sessile, obovoid, 0.8–1 × 0.4–0.5 mm, apex obtuse, scarcely apiculate, surfaces glabrous. |
Cyperus giganteus |
Cyperus dentatus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, marshes | Emergent sandy, peaty, or gravelly shorelines |
Elevation | 0–10 m (0–0 ft) | 0–600 m (0–2000 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
CT; DC; DE; IN; MA; MD; ME; NC; NH; NY; PA; RI; SC; TN; VA; VT; NB; NS; ON; QC
|
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 report of Cyperus dentatus from West Virginia (M. V. McGivney 1938) is erroneous; the cited specimen was from New Jersey (Gutenberg s.n. 1886, US) (M. Strong, pers. comm.). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 173. | FNA vol. 23, p. 151. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Torrey: Fl. N. Middle United States 1: 61. (1824) |
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