Molecular phylogenetics and molecular dating of the New Zealand Gleicheniaceae

The Gleicheniaceae are an ancient family of ferns, with three of the six extant genera occurring in New Zealand: Dicranopteris, Gleichenia, and Sticherus. The biogeographic origins of this family in New Zealand are unknown, and the taxonomy of Gleichenia in particular is still unclear. To address aspects of these two issues, DNA sequences from the trnL-trnF locus and the rbcL gene were produced for all of the common Gleicheniaceae species in New Zealand, as well as for Gleichenia alpina from Tasmania and Sticherus cryptocarpus from Chile. Several trnL-trnF haplotypes were found amongst New Zealand G. dicarpa. One of these haplotypes was also observed in Tasmanian G. alpina, while the other New Zealand G. dicarpatrnL-trnF haplotypes were more similar to those of G. microphylla. These results suggest the taxonomy of New Zealand Gleichenia may be more complex than presently recognized. Molecular dating of the rbcL sequences with the program r8s rejected vicariant explanations for the disjunct distributions between New Zealand and elsewhere for each of Dicranopteris, Gleichenia, and Sticherus. However, the direction of the inferred long-distance dispersal was not resolved.