Cypress swamps are communities that are dominated by bald cypress trees. These ecosystems assume differences in response to abiotic and biotic factors. The big cypress swamp, much of which is in Big Cypress National Preserve, is mostly composed of these types of communities. Other plants growing in the understory of big cypress swamp, are swamp fern, spikerush and marsh fleabane. Among the woody plants found in the understory are buttonbush, cocoplum, willow and wax myrtle.