A Phylogenetic Investigation of the New Zealand Pteridaceae Ferns
The fern family Pteridaceae is among the largest fern families in New Zealand. It comprises 17 native species among five genera. Traditionally the classification of Pteridaceae was based on morphological characters. The advent of molecular technology, now makes is possible to test these morphology-based classifications. The Pteridaceae has previously been subjected to phylogenetic analyses; however representatives from New Zealand and the South Pacific have never been well represented in these studies. This thesis research aimed to investigate the phylogenetic relationships of the New Zealand Pteridaceae, as well as, the phylogenetic relationships of the New Zealand species to their overseas relatives. The DNA sequences of several Chloroplast loci (e.g. trnL-trnF locus, rps4 and rps4-trnS IGS, atpB, and rbcL) were determined and the phylogenetic relationships of the New Zealand Pteridaceae and several species-specific question within the genus Pellaea and Adiantum were investigated. Results presented in this thesis confirm previously published phylogenetics of the Pteridaceae, which show the resolution of five major clades, i.e.,cryptogrammoids, ceratopteridoids, pteridoids, cheilanthoids, and the adiantoids. The addition of the New Zealand species revealed a possible South West Pacific groups formed by the respective genera, where New Zealand species were generally more related to one another than to overseas relatives. Within the New Zealand Pellaea, the analysis of the trnL-trnF locus sequence data showed that the morphologically-intermediate plants P. aff. falcata, responsible for taxonomic confusion, were more closely related to P. rotundifolia than to P. falcata. Furthermore, the species collected on the Kermadec Islands, previously thought to be P. falcata, are genetically distinct from the Australian P. falcata and they could constitute a new species. Adiantum hispidulum, which is polymorphic for two different hair types being used to distinguish them as different species, was also reinvestigated morphologically and molecularly. Morphological inspection of hairs revealed three hair types as opposed to the previous thought two, and furthermore, they correspond to three different trnL-trnF sequences haplotypes.