Hi Maggs,

I agree that it certainly looks like an Epiphyllum. Do a search on the internet and see if your flower matches anything there. If it is that, you may have quite a job trying to catch the flower in bloom (being so high in your tree) since many of them open in the late evening and by daybreak they are gone. Very beautiful blooms and highly scented. In this forum look in "the Jungle' section there are some pics. there.