Drosera filiformis var. floridana is hereby elevated on species rank to Drosera floridana on account of its unique morphology, ecology, and phenology, by which it differs from both the allopatric D. filiformis and sympatric D. tracyi. An amended description is provided for D. floridana, including differential stipule and flower characters presented here for the first time. Its distribution, biology and conservation are discussed, and the species is illustrated in comparison to its two closest relatives. As an additional taxonomic consequence, D. × californica nothovar. arenaria, the natural hybrid between D. floridana and D. tracyi, likewise must be newly combined to species rank, D. × arenaria. Drosera floridana is the most geographically restricted sundew species of North America, endemic to the Greenhead Slope Lake Region and spanning only two counties in the state of Florida (in contrast to the broad Gulf Coastal plain range of D. tracyi and the scattered mid to northern Atlantic Coast distribution of D. filiformis). Naturally, D. floridana is associated with quartz sand littoral zone seepage areas, a phenomenon exclusive to a small number of oligotrophic lakes in Bay and Washington counties, Florida. Drosera floridana does not outcompete D. tracyi and resulting hybrids in the absence of its preferred ecotone of intermediate moisture ephemerality between the sympatric congeners D. tracyi and D. capillaris. In contrast, D. tracyi occurs beside Sarracenia spp. in wet wiregrass pine savannas, while D. filiformis is more generalist, inhabiting Sphagnum bogs, late-successional woodland seepages, non-seepage lake littoral zones, and bay rims of clay or sand-based pocosins.