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Worldwide there are some 900 species of Cyperus, wetland and terrestrial. Very complex inflorescences make them difficult to identify casually; spikelets and nutlets are essential for their species identification. Some are grown for food, fibers and perfume; some are considered to be among the “worst weeds in the world”, some provide significant benefits to wildlife. In Florida there are over 50 variations of Cyperus alone (Wunderlin, 2003). The species is represented in nearly every state of the U.S. (Kartesz, 1999).

Flat sedges are sedges. Stems solid, often 3-angled, unbranched, leafy at base; leaf blades from tubular sheaths; inflorescences terminal (on stem tips) well above the leaves, spike-like or in many heads, branched; bracts long, leaf-like (growing around the stem just below the inflorescence); spikelets clustered, axis jointed, spikelet scales in 2 rows; fruit a 2- or 3-sided achene (nutlet).

For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.

Cyperus croceus	Cyperus involucratus	Cyperus rotundus	Cyperus sphacelatus

View the from the University of Florida Herbarium Digital Imaging Projects.