Biosystematics and taxonomy of the Ozothamnus leptophyllus (compositae) complex in New Zealand
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy (PhD)
Historically, Ozothamnus in New Zealand has been separated into five endemic species and seven varieties, and more recently united into a single, undivided, but polymorphic species. However, investigation leading to the recognition of a single species was limited and many botanists continue to recognise different forms within this species based on appearance and distribution. The conflicting taxonomic opinions regarding 0. leptophyllus are influenced by complex patterns of variation, mostly quantitative taxonomic characters, and wide distribution with overlapping ranges. In order to resolve the taxonomy of 0. leptophyllus, morphological and genetic diversity within and among populations are assessed from throughout New Zealand and a comprehensive revision is undertaken. Eighty morphological characters are assessed for 192 OTU s from 90 populations, covering the distribution and observed variation of 0. leptophyllus throughout New Zealand. Agglomerative clustering methods and principal coordinate analysis are used to detennine groups within the morphological data sets. Amplified fragment length polymorphism (AFLP) is used to examine the genetic diversity within 0. leptophyllus. The genetic diversity between populations is assessed based on single individuals from 23 populations throughout New Zealand, while 12 individuals from a single homogeneous population are used to assess intra-population variation. Strong congruence is found between the results of morphological and AFLP analyses, indicating that the morphological pattems of variation have a genetic basis. The resulting groupings support the presence of distinct entities showing variation at a similar level. These entities are recognised here as six subspecies. One subspecies can be fmiher divided into subgroups, recognised here as three varieties. Descriptions of the taxa, typification, and a dichotomous key are provided to facilitate their identification.