Molecular phylogenetics and biogeography of Hawaiian members of the pteridophyte genus Cibotium (Dicksoniaceae)

Abstract

Although ferns comprise a significant proportion of Hawaii’s native vascular-plant flora, few phylogenetic studies have been performed to infer relationships among taxa and to deduce their biogeographical origins. Species from the pteridophyte genus Cibotium can be found among the canopy in the Island’s montane regions and were the focus of this study. Four species of Cibotium are endemic to the Hawaiian Archipelago and ten species exist worldwide. The goal of this study was to determine whether Hawaiian Cibotium is monophyletic and to discover the biogeographical origins ofthe species. Two chloroplast DNA fragments, trnL-F IGS and rbcL, were sequenced and maximum parsimony, maximum likelihood, and neighbor joining analyses were performed. These analyses support a South American origin for a monophyletic Hawaiian Cibotium. This supports the hypothesis that the ancestor of Hawaiian Cibotium colonized Hawaii by wind dispersal of spores via a combination of the ICTZ, Hadley Cells, and trade winds.