Taxonomic Delimitation Within New Zealand Lobelioideae
The purpose of this study was to re-examine the morphological characters of native New Zealand Lobelioideae, and to use those characters, in concert with existing genetic data, to help inform a global effort at constructing a more natural classification of all Lobelioideae. The history of Lobelioid discovery and classification is presented, with a focus on the New Zealand taxa and the historic concept of delimitation of genera within the subfamily. The problems with the most recent taxonomic arrangements of the New Zealand species is discussed in light of field identification problems and new genetic data. Plants of almost all New Zealand species were located and observed both in the field and in cultivation. A factorial experiment testing the range of morphological plasticity for several of the species under different water and light conditions was conducted and results confirmed historical reports of increased morphological similarity between some species under certain conditions. Floral and fruit characteristics of all available species were microscopically examined for fine scale morphological differences to confirm historical reports and resolve disputes about true character states. A pollination experiment was conducted in an attempt to establish the degree of genetic difference between the species. Limited results were obtained as the experiment was compromised by a confluence of factors. However, two putative hybrids between Lobelia fatiscens and Lobelia ionantha have been successfully generated and maintained in cultivation. In conclusion, temporary transfer of all New Zealand species to the genus Lobelia is supported and key information gaps are identified that must be filled for future investigators to move forward in delimiting new genera within the sub-Family. The difference between fleshy and capsular fruits within this species group is discussed and the character state is clarified for all species. Finally it is suggested that certain clades within the new molecular phylogeny may be appropriately treated as genera pending the outcomes of additional suggested investigations.
Advisor: Lord, Janice
Degree Name: Master of Science
Degree Discipline: Botany
Publisher: University of Otago
Keywords: Lobelia; plant taxonomy; Lobeliaceae; alpine plants; morphology; phylogenetics; natural history
Research Type: Thesis