Cyperus giganteus

Illustrator: Yevonn Wilson-Ramsey

Copyright: Flora of North America Association

Herbs, perennial, rhizomatous, stout. Culms roundly trigonous, 200–350 cm × 15–50 mm, glabrous. Leaves bladeless. 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. 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. 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.

Phenology: Fruiting summer.
Habitat: Stream banks, marshes
Elevation: 0–10 m

Distribution

• Generated Map
• Legacy Map

La., Tex., Mexico, West Indies, Central America, South 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.

Selected References

Haynes, R. R. and A. Lasseigne. 1969. Cyperus giganteus (Cyperaceae) in Florida. Sida 3: 345.

Lower Taxa

None.