Large areas of freshwater marl prairie border the deeper sloughs of the Everglades. These relatively short-hydroperiod marshes are typified by a diverse assemblage of low-growing vegetation.  

A complex mixture of algae, bacteria, microbes, and detritus that is attached to submerged surfaces, periphyton serves as an important food source for invertebrates, tadpoles, and some fish. Periphyton is conspicuous and is the basis for the marl soils present. The marl allows slow seepage of the water but not rapid drainage. Though the sawgrass is not as tall and the water is not as deep, freshwater marl prairies look a lot like freshwater sloughs.