Cyperus giganteus |
Cyperus serotinus |
|
---|---|---|
giant flatsedge, Mexican papyrus |
tidalmarsh flatsedge |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, perennial, stoloniferous; stolons terminated by tubers. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
trigonous, 50–100 cm × 5–8 mm, glabrous. |
Leaves | bladeless. |
3–6, V-shaped, 20–50 cm × 5–8(–10) 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. |
spikes not appearing lateral, rays 5–8, 2–7(–12) cm; bracts 3–4, ± horizontal to ascending at 45°, V-shaped, 5–25 cm × 1.5–8 mm; spikes 1–4, ovoid, 2–4 × 2–3 cm; rachis 1–2.7 cm, smooth or hispidulous; rachilla persistent, wingless or with hyaline wings scarcely 0.1 mm wide. |
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. |
7–14, flattened, lanceoloid, 10–20 × 2–2.5 mm; floral scales 10–30, laterally dark brown to reddish brown, medially greenish, laterally 5–9-ribbed, ovate-deltate; anthers 3, 0.5 mm; styles 0.5 mm; stigmas 1.2–1.6 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. |
|
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
brown, sessile, ellipsoid, 1.4–1.6 × 1.4–1.5 mm, apex obtuse, apiculate. |
Cyperus giganteus |
Cyperus serotinus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, marshes | Tidal marshes |
Elevation | 0–10 m (0–0 ft) | 0 m (0 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
DE; NJ; PA; Eurasia [Introduced in North America] |
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.) |
|
Source | FNA vol. 23, p. 173. | FNA vol. 23, p. 164. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Juncellus |
Sibling taxa | ||
Synonyms | Chlorocyperus serotinus, Juncellus serotinus | |
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Rottbøll: Descr. Pl. Rar., 18. (1772) |
Web links |