Lygodium japonicum (Thunb. ex Murr.) Sw. is an invasive fern in the southeastern United States. This perennial fern, which produces twining fronds from underground rhizomes (Clarke 1936), is native to open forests and forest edges in temperate, subtropical and tropical regions of eastern and southeastern Asia, East Indies, and northern Australia (Singh and Panigrahi 1984, Munger 2005, Willis et al. 2006). Lygodium japonicum was introduced to North America as an ornamental; the first known wild populations were recorded in Georgia in 1903 (Pemberton and Ferriter 1998), but this fern is now widespread in the southeastern United States. Japanese climbing fern occurs in human-modified habitats, as well as forests and woodlands (Langeland and Burks 1998, Rosen et al. 2003), where it often forms dense mats that grow on and cover native species (Gagnon et al. 2005, Zeller and Leslie 2004). Some management plans have emphasized the dearth of scientific data on invasions by climbing ferns (e.g., Ferriter 2001).