干旱区生态环境知识资源中心

Craspedia (Asteraceae: Gnaphalieac) is a genus of 23 species found only in Australia and New Zealand. Maxiinum parsimony arid maximum likelihood analyses of ITS and ETS intergenic spacers from the nuclear genome recovered three main lineages. The first lineage consists solely of the Australian species C. haplorrhiza, the relationships of which are unresolved, and the second includes species that are also exclusively Australian in distribution. The third lineage comprises two monophyletic groups; one including all the remaining Australian species sampled and the other, all New Zealand entities sampled. Monophyly of New Zealand Craspedia is also supported by analysis ofpsbA-trnH intergenic spacer sequences. Australian alpine species are independently derived from within the two larger Australian lineages. Both major Australian lineages are present in Tasmania suggesting multiple colonisations from mainland Australia. The single lineage of New Zealand Craspedia and the low divergences between Australian and New Zealand Craspedia samples are consistent with the derivation of New Zealand Craspedia via a single dispersal event from south-east Australia in the Late Tertiary or Quaternary. Compared with Australian Craspedia, the New Zealand species show extensive morphological divergence but little sequence divergence, suggesting a recent and rapid species radiation.