There are about 150 species of spikerushes worldwide, many aquatic, with about 2 dozen species native to Florida (Wunderlin, 2003). They may be encountered as floating tangled mats or dense clumps in the mud or as rooted green spikes emersed from a few feet of water, covering many acres. Some are cultivated as human food; some species are major food plants of birds and other animals.
Spikerushes are sedges. Stems unbranched, many gas canals in cross section; leaf blades none, just sheaths at the base of the stem; inflorescence a single spikelet, on stem tips, no bracts; spikelets of various sizes, overlapping scales, few-to-many flowers.
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.