I would say the Eucalyptus tree, planted all over the world but native to Australia, is quite unusual.
Young Eucalyptus trees have leaves that are rounded and are arranged opposite to one another. However, when mature the leaves of a Eucalyptus are lance-like and are arranged in an alternating fashion. This to me is quite unusual.
All I know about them is they're bad railroad ties, and they explode.
Which Eucalyptus tree? There are between 700-900 species and they look nothing alike.
See E. grandis, E. tetraptera, E. chartaboma, E. deglupta, E. pulverulenta for examples of diversity
Some are incredibly tall with really smooth skin, some are basically bushes, some have really messy papery bark; some even have rainbow bark! Some have really long leaves while some have extremely short tightly wound round leaves
It's funny, a neighbor had me cut their eucalyptus down, then it grew back from the stump and I had to cut it again a couple years later. Then I has to cut it again a few years after that. Now it looks like I'm going to have to cut it again soon. It's become a running joke at this point.
Those things are tough, and they grow really fast in the right climate.