It really does look like a Tabernaemontana, but what's bothering is that the few photos I can find on the web of the genus' seedpods are so different from mine..
https://www.google.be/search?q...
Flora do Brasil is still off line..
As it is in a botanical garden it could also be from another tropical country..
I am sure now I didn't put it up before in this forum, I have gone meticulously through all my posts from 2015 once again..
