Not only koalas,
and other marsupials are unique to Australia with their origin uncertain or unknown.
One of the mysteries is Xanthorrhoea - the "grass tree".
This tree is highly unlikely to have evolved from anything on Earth, simply because
it is not related to anything else that we can find here.
Not only the shape of the tree, but also the bark is highly
unusual. It feels like a cork, but resembles a honeycomb structure.
What could be the origin of Xanthorrhoea tree?
In The Book you will find an interesting story about the
origin of Xanthorrhoea.