Science researcher Lara Shepherd explores kōwhai trees, one of New Zealand’s most widely recognised native plants and our unofficial national flower.
Did you realise that we actually have eight species of kōwhai in New Zealand? Our DNA research investigating the relationships of these kōwhai species and where kōwhai trees were located during the ice ages has just been published.
How are New Zealand kōwhai species related to each other?
Our genetic results show that kōwhai species share DNA with each other. This sharing of DNA likely occurs through hybridisation between the species and makes it difficult to construct a family tree of relationships for kōwhai. Prostrate kōwhai is the only species we were able to distinguish with the DNA markers we used.
Where were kōwhai trees found during the most recent cold spell of the ice ages?
Using our DNA results we were able to tell that Sophora survived the Last Glacial Maximum of the ice-age (~30,000 years ago) throughout much of the country, rather than being restricted to only a few refugia in the warmer places. This result is consistent with our past studies of the other lowland plants fierce lancewood and Hooker’s spleenwort.
The widespread survival of New Zealand lowland plants contrasts with Europe and North America, where the climate during the Last Glacial Maximum was so severe that many species had to retreat hundreds of kilometres to warmer refugial areas.