It is ambiguous without external context; and is used to demarcate the last item in the list (at least that's what I was taught in school in the UK).

For example:

  To joe blogs, the pope, my cat and ferrari.

So the Pope is called Joe and is a cat?

Let's think for a moment. How would I write that if Pope Joe was my Cat?

  To joe blogs (the pope and my cat) and ferrari.

And for your example, if I only had the comma to punctuate then this is the only way I could write it unambiguously:

  To my mother Ayn Rand, and my daughter.

I think that this whole thread is an excellent argument against any attempts to encode any sort of rule set in a language wholly incapable of encoding it unambiguously.