New Olearia Species RecognisedOlearia capillaris Buchanan was described by pioneer botanist John Buchanan in 1871 using plant material collected by Henry H. Travers from an unspecified location in Nelson. The name has been widely used for the last 134 years, that is until, in the most recent issue of the New Zealand Journal of Botany 43(3), Landcare Research botanist Dr Peter Heenan demonstrates that the type of O. capillaris is actually based on a naturally occurring hybrid involving O. arborescens (G.Forst.) Cockayne et Laing and, ironically, the divaricating shrub that botanists have been erroneously calling O. capillaris all these years! This being the case the divaricating shrub is now without a formal name having never been officially recognised as undescribed. In Dr Heenan’s paper this situation is rectified and the shrub is formally described as Olearia quinquevulnera, the name referring to the red-purple blotches that surround each of the five teeth that usually occur along the leaf margin. O. quinquevulnera, despite its distinctive divaricating morphology is most closely allied to O. arborescens, with which it freely hybridises to produce Olearia xcapillaris Buchanan. Two other hybrids are recognised, O.xsuavis Cheeseman (O. lacunosa x O. quinquevulnera), and O. ilicifolia Hook.f. x O. quinquevulnera. Aside from Olearia xcapillaris, the other two hybrids are considered uncommon. Olearia quinquevulnera is described as having a ‘disjunct distribution with small and widely scattered populations, and these characteristics make the estimation of its conservation status difficult….’ . Dr Heenan suggests it should be rated as ‘At Risk/Sparse’ qualified as Conservation Dependent (CD) and Data Poor (DP) because most populations are subject to introgressive hybridisation with O. arborescens, the nature of which needs further research, and exact numbers of plants and/or trend data is unavailable. The highly disjunct nature of this species, and the often small population sizes make it an ideal species for research into gene-flow, and the effects of introgressive hybridism.
Posted: 19 September 2005