I'd often wondered what this flower was and was pleased to find a name for it. Native Frangipani or Hymenosporum flavum. This particular tree in the Maroochy Botanic Gardens only had a slight fragrance but I've read that they can have quite a sweet scent but then there is also talk about a red centre, which these definitely didn't have. Maybe it depends on the area or type of tree. I have to confess that nice as these are, I prefer their more famous (and colourful) namesakes.