Supporting data from: The distribution of leaf form among indigenous woody angiosperms in New Zealand

New Zealand’s woody indigenous eudicot flora comprises a variety of leaf
shapes and features and occupies environments extending from subtropical
to cold temperate climates. We used a dataset of over 300,000 occurrences
of 557 indigenous woody eudicot species to investigate patterns and trends
in the occurrence of six leaf features (leaf pubescence, leaf margin
teeth, leaf size, leaf apex and base shape, and leaf length to width
ratio) along critical climate gradients. Major climate variables examined
included temperature, precipitation, moisture deficit and solar radiation.
Our results reveal strong latitudinal gradients in toothed leaves and leaf
area with both declining at higher latitudes. Leaf base and leaf apex
angle are also aligned latitudinally, both declining in northern areas. In
contrast, the occurrence of pubescent leaves and leaf length to width
ratio are independent of other leaf features and latitudinal gradients.
Larger leaves are positively associated with warmer climates while
serrated margins are more common in warmer and wetter zones. The
occurrence of pubescent leaves is greatest in seasonally dry environments
with low annual precipitation. Long thin leaves (high length to width
ratio) were more common in areas with a high rainfall to potential
evapotranspiration ratio. Leaf apex angle is negatively correlated with
temperature while leaf base angle distribution in relation to climate was
highly variable. Overall, results confirm global patterns for leaf size
and climate, highlighting the importance of small leaves limiting heat
loss in cool climates. The positive correlation between leaf teeth and
warmer climates has not been found elsewhere. High occurrence of pubescent
leaves in low rainfall and highly moisture deficient environments in New
Zealand suggests that the trait is associated with water retention in dry
climates.