Epiphytism and terrestrialization in tropical Huperzia (Lycopodiaceae)

A phylogenetic analysis of Huperzia (Lycopodiaceae) documents a single orig in of epiphytism and multiple reversals to a terrestrial habit in the Neotr opics. Epiphytism evolved prior to the final rifting of South America and A frica, but the origin of most modern species diversity probably postdates t he Mid Cretaceous diversification of flowering plants. In this respect, the evolution of Huperzia parallels that of many other Neotropical epiphytic g roups. In the Andes, alpine terrestrial species are shown to have evolved f rom montana epiphytes, an event that correlates well with regional orogenes is during the Miocene. Species from Australia, New Zealand, and Tasmania sh ow diverse relationships with SE Asian groups. Results also indicate that l ong distance, transoceanic dispersal is rare in these homosporous plants - accounting for less than 5% of species distributions - and that convergence in strobilus and branch morphology is widespread among Paleotropical and N eotropical epiphytes. The phylogenetic analysis is based on a sample of 63 species (c. 15% total species diversity) and data from a c. 1.1kb region of noncoding (intron and spacer sequences) plastid DNA located between the tr nL and trnF genes.