I bought this plant from a local nursery in December last year. It was labelled as a gardenia, but after doing a little pruning, re-potting and wiring I began having doubts that it's not a gardenia. My suspicions were proved right when a small flower bud formed and finally opened a couple of days ago. The flower has sprouted directly on a branch not far from the main trunk, which is not where gardenia flowers grow. It looks like perhaps a magnolia of some sort

Does anyone recognize this plant?
Thank you in anticipation