Taxonomy of ranunculus in Tasmania

A taxonomic treatment has been made of Ranunculus in Tasmania. Mainland species have been included in some aspects of the work especially where they have particular bearing on the Tasmanian species. The approach was multifaceted and included traditional taxonomic methods of examination and description, and experimental investigations. Three new species have been described. Two species, R. decurvus and R. concinnus showed such close morphological similarity that multivariate morphometric analyses were employed to try to separate them. These analyses, principal components analysis, discriminant function analysis and a clustering technique, resulted in R. concinnus being considered a synonym under R. decurvus. An updated key for Tasmanian Ranunculus has been produced. Chromosome counts were made of 35 species. Intraspecific polyploid complexes were shown to occur in two native species, R. glabrifolius and R. amphitrichus. Transplant and controlled-environment growth experiments were conducted to investigate the polymorphism in R. nanus. Aspects of variation examined included leaf area, dentateness, petiole length and hairiness. These characters were shown to be phenotypically plastic. Different fixed genotypes of R. nanus occur in different habitats. A preliminary survey of the occurence of flavonoids was conducted. This line of research shows great potential as a method of elucidating the relationships between the species. One compound was identified as rutin and three other compounds were partially identified. 'Recent' evolution is indicated for many of the species and the processes of speciation are apparent. The alpine species show a high level of endemism. Inter-continental relationships are few. This study concludes with some general comments on the possible causes and evidence for these statements.