Eucalyptus cinerea or The Silver Dollar Tree has very distinctive, circular bluey green leaves - though they can mature as more sickle shaped.
It is very fast growing, is of a naturally twisted or gnarled habit and bears creamy flowers in mid-summer.
Although reaching 15metres+ in the wild, it rarely grows past 10 metres in domestic settings.
The distinctive foliage is prized by florists as a backgrounder to floral arrangements.