Olearia

Abstract: Analyses of ITS sequences for 49 species of Olearia, including representatives from all currently recognised intergeneric sections, and 43 species from 23 other genera of Astereae, rooted on eight sequences from Anthemideae, provide no support for the monophyly of this large and morphologically diverse Australasian genus. Eighteen separate lineages of Olearia are recognised, including seven robust groups. Three of these groups and another eight species are placed within a primary clade incorporating representatives of Achnophora, Aster, Brachyscome, Calotis, Camptacra, Erigeron, Felicia, Grangea, Kippistia, Lagenifera, Minuria, Oritrophium, Peripleura, Podocoma, Remya, Solidago, Tetramolopium and Vittadinia. The remaining four groups and three individual species lie within a sister clade that also includes Celmisia, Chiliotrichum, Damnamenia, Pleurophyllum and Pachystegia. Relationships within each primary clade are poorly resolved. There is some congruence between this molecular estimate of the phylogeny and the distribution of types of abaxial leaf-hair, which is the basis of the present sectional classification of Olearia, but all states appear to have arisen more than once within the tribe. It is concluded that those species placed within the second primary clade should be removed from the genus, but the extent to which species placed within the first primary clade constitute a monophyletic group can only be resolved with further sequence data.

Abstract: Somatic chromosome numbers are documented for 59 taxa, including three ornamental cultivars, in 20 genera and 15 families from the New Zealand region. Chromosome counts are also provided for Australian and Norfolk Island representatives of Coprosma (two species) and Melicytus/Hymenanthera (four taxa).

Abstract: Morphological and ITS (internal transcribed spacer) sequence data for 40 species of the Austral-Pacific genera Camptacra, Kippistia, Minuria, Peripleura, Tetramolopium, and Vittadinia as well as one semiherbaceous species of Olearia were subjected to cladistic analysis, separately and together. Minuria, Peripleura, and Tetramolopium are paraphyletic as currently defined. Tetramolopium vagans from Australia appears to represent an undescribed genus. Both Kippistia suadefolia and Peripleura diffusa show close affinity to Minuria species, and Minuria macrorhiza appears to contain two distinct but closely related species. Vittadinia and the remaining species of Tetramolopium and Peripleura form a strong affinity group. The distribution of indels and the combined analysis each provide evidence that the Hawaiian and Cook Island species of Tetramolopium are descended from New Guinea species. The combined analysis also suggests that the Cook Island species T. mitiaroense is sister to the Hawaiian clade. Olearia arguta groups strongly with Camptacra and shows no close affinity with either of the arborescent species of Olearia used to root these analyses. Marked homoplasy among morphological characters indicates why generic delimitation in the group has been problematic.

Abstract: Radiocarbon ages were derived from 12 individuals representing four species of woody understorey plants growing in the Eucalyptus regnans dominated Wet Forests of Victoria's Central Highlands. Cyathea australis, Dicksonia antarctica and Olearia argophylla are common and often dominate the understorey. The fourth species, Persoonia arborea, is a small understorey tree endemic to this region. Field observations and radiocarbon ages for these four species (up to 370 ± 70 years BP) indicate they are capable of surviving fire and are long-lived in this environment.