purple nutsedge, nutgrass, chaguan humatag, cocograss, kili'o'opu, pakopako, purple nutsedge
- 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