Asplenium serratum, the Bird's nest spleenwort and Wild birdnest fern, is a fern native to Brazil, the Caribbean, and the United States. It is rare in central and southern Florida, where it is a state-listed endangered species.Asplenium serratum is an epiphytic or lithophytic fern that grows on eroded limestone, tree trunks, rotting stumps, and fallen logs.