The swamp lily aka string lily (Crinum americanum) is a native tropical perennial found throughout Florida and much of the southeastern United States. It is an obligate wetland species. This means under natural conditions you will almost always see them growing in wetlands. This includes: wet prairies, depression marshes, ditches, hydric hammocks, floodplains, riverine marshes, and wet pastures (to name a few). The lily is a bulb, and it is extremely difficult to extract these guys from the ground. The large flowers are very fragrant and showy. And its fruiting body is a large capsule that is 4-6 cm wide and can have 1 to many large fleshy seeds inside.
People sometimes confuse these flowers with members of the spiderlily (Hymenocallis) genus. However, the swamp lily has a very distinctive feature to look for: bright red, purple, or pink stamen filaments (which you can see in the photos).