Divaricating plants such as the Coprosma species were a widespread form of vegetation on the eastern drylands in both the South and North Islands of New Zealand.
The scientific debate over why these plants developed small leaves and criss-crossed branches is yet to be resolved.
Some theories suggest that divarication is an adaptation to the grazing behaviour of the now extinct moa over many, many centuries. These adaptations are theorized to have increased the resistance of plants to the browsing action of moas.
Other explanations speculate that divarication results from the response of plants originating in tropical climates to climatic cooling in the ice ages, or some combination of both theories.