- Cyperus rotundus is a perennial which rarely reproduces by seed but extensively reproduces by rhizomes which initially are white and fleshy with scale leaves, later becoming ligneous or "wiry."
- The leaves are three-ranked, shiny, dark green, and corrugated in cross section. They are 0.24-0.39 in. (6-10 mm) wide and 3.9-13.8 in. (10-35 cm) long. The rachis, which grows through the center of the leaf bundle, is erect, simple, smooth, triangular in cross section, and 3.9-23.6 in. (10-60 cm) long.
- Near the ends are clusters of narrow spikelets, 0.3-1 in. (0.8-2.5 cm) long and 0.07 in. (2 mm) wide, 10- to 40-flowered, acute and compressed with a red, reddish-brown, or purplish-brown color.
- Fruits are 3 angled achene.
- Ecological Threat
- Infests crop production areas in tropical and temperate climates, causing large losses in crop yields.
Global Invasive Species Database. 2011. Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission 
University of California, Jepson Flora Project 
Flora of North America, www.eFloras.org 
Virginia Tech Weed Identification Guide 
University of Florida IFAS Extension 
Wildscreen, ARKive 
USDA NRCS PLANTS 
USDA ARS GRIN 
Images from Bugwood.org