What make plants unique?

Answer 1

Australia has a unique flora, consisting of around 22 000 species of plants. More than 90 per cent are indigenous, and many species are not found anywhere else than Australia. The evolution of Australia's flora was a result of Australia's long isolation from other continents. The evolution of flora first began in the Cretaceous period which was around 136 million years ago in the Southern continents. In Australia, there was a huge flood during the Cretaceous period which broke the continent into four islands. During these floods, the flora on each island diversified and evolved, and each island ended up with its own unique flora. This was due to the long period of stability that arose.