What kind of fruit is this?

[SonnyCrockett]

Maybe this one is obvious to you guys.  This fruit is on a vine planted near a pool in the Keys.  Looks like a hybrid apple-plum-mango fruit on the outside.  And while that would be cool, obviously that's not what it is.  The vine looks grafted.  The fruit does not look edible.  When I cut one open, the inside was white and had the feel of a nerf foam ball.  Not sure if it was ripe or not.

So, what is it?

[greenman62]

thats pretty odd.
if its grafted, it must be for a reason.

i think most nursery grown plant which are non-fruiting, non-edible
would be from cuttings, air-layers or seed.
im sure there are a few plants grown for looks (flowers and foliage),
which are grafted, but, i am thinking not too many.

did you see the flowers ?
is it that attractive of a plant ?

Akebi family maybe ?

[Guanabanus]

No idea.

[9B in Brazil]

Could it be a Stephanotis?

[SonnyCrockett]

Could it be a Stephanotis?

I think you're right.  Stephanotis Floribunda aka "Madagascar Jasmine".  Most pictures of the "fruit" I saw online were all-green, while the ones I saw on this vine were purple and green, but the shape is the same and the leaves on the vines are the same.  The one I saw didn't have any flowers on it, because apparently the blooming season is in the spring time.

From what I read, the "fruit" matures further on the vine and splits along the seam allowing many seeds with white tufts to fly away in the wind.  The one I cut open hadn't developed that far yet.  I could just make out where the seeds were forming.  Cool looking "fruit" though.  Thanks for the help guys.