Trees as Individuals

Trees of different species are partly identified by the distinctive shape of their leaves.  But leaves from different trees of the same species often differ in remarkable ways.  Observing such intra-species differences is one way of recognizing the individuality of trees.

The six leaves in the row above come from the end of a single branch of a White Oak tree. The lobes of these leaves are simple structures with uniformly rounded ends.  Minor varations in midrib curvature and in the number of fuly formed pairs of lobes do not obscure the overall resemblance among the leaves.  The rounded, simple lobes characterize White Oak trees and it is this shape that most tree identification images use.  Unelaborated, smoothly rounded lobes constitute a shape norm for the White Oak leaf.

But White Oak leaves vary enormously.  The leaves in the group below come from the same tree.  They resemble one another, but differ noticeably from the leaves of the first group.  Their primary lobes tend to form smaller, secondary lobes. In addition, the lobes tend to square off at the tips.

It is probably not known how many varieties of White Oak leaf shapes there are.