Slicko is quite correct. The general populous do call all eucalypts 'gums'. I only learnt recently that there are different types of eucalypts, of which gum is only one of them. There are also: Iron Bark, Peppermint, Stringy Bark, Box, Wrinkled Bark and Mallee. Well at least these are the Victorian ones.
Then you have different species and varieties of each and of course they all produce different honey with distinct flavours and pollen of different quality. Yellow Box and Messmate (a stringy bark) are two of the most common.