1 Shrub or small tree with several trunks; all leaves attached oppositely, sessile……….Eucalyptus pulverulenta
1′ Small or medium-sized tree with one trunk; some leaves attached alternately, petiolate
  2 Buds and fruits in simple clusters of three
  in leaf axils……….Eucalyptus gunnii
  2′ Buds and fruits in branched clusters of
  seven at shoot tips……….Eucalyptus
  polyanthemos