PhD scholarship: Dating the evolution of the divaricate growth form in the New Zealand flora
The single most controversial feature of the New Zealand flora is the small-leaved, twiggy, tangled (“divaricating”) growth form that has evolved locally in at least 17 different plant families. Prolonged debate about this remarkable case of convergent evolution has been polarized around two well-known hypotheses. First interpreted as a response to the Plio-Pleistocene onset of frosty droughty conditions, divaricate forms are now widely regarded as an anachronistic defence against large browsing birds (moa) that went extinct shortly after human arrival during the last millennium. Resolving this controversy is vital for understanding the status of divaricate plants in contemporary New Zealand, and for predicting the likely impact of browsing mammals and climate change on their future abundance and distribution.