Epiphytism and terrestrialization in tropical Huperzia (Lycopodiaceae)

• Published in: Plant systematics and evolution Vol. 218; no. 3/4; pp. 221 - 243
• Main Authors: Wikström, N., Kenrick, P., Chase, M.
• Format: Journal Article
• Language: English
• Published: Springer 01.01.1999
• Subjects: Angiosperms; Biological taxonomies; Epiphytes; Evolution; Forest canopy; Montane forests; Phylogenetics; Plants; Species diversity; Vegetation
• ISSN: 0378-2697; 1615-6110
• DOI: 10.1007/bf01089229

A phylogenetic analysis of Huperzia (Lycopodiaceae) documents a single origin of epiphytism and multiple reversals to a terrestrial habit in the Neotropics. Epiphytism evolved prior to the final rifting of South America and Africa, but the origin of most modern species diversity probably postdates the Mid Cretaceous diversification of flowering plants. In this respect, the evolution of Huperzia parallels that of many other Neotropical epiphytic groups. In the Andes, alpine terrestrial species are shown to have evolved from montane epiphytes, an event that correlates well with regional orogenesis during the Miocene. Species from Australia, New Zealand, and Tasmania show diverse relationships with SE Asian groups. Results also indicate that long 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 Neotropical 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 trnL and trnF genes.