Discovered this on my back fence.  After some research I think it is a passon fruit of some kind.  Can anyone enlighten me?

That is what it is. There are a bunch of different passiflora's.  They are a weed here in Florida.  The fruit is quite good tasting but has an odd consistency and seedy.

We call them May Pops here in north Georgia.  I haven't eaten one in years used to eat them a lot as a kid.  I recall them being tasty kind of tangy but that was a long time ago.

goss

Passiflora incarnata  Common Name Maypop. Edible, but I have never found a fruit I really enjoyed, all seemed like cottony foam. I hear you can make jelly from it. GREAT wildlife plant Butterflies love as do their Larva on foliage. Fruits I am sure consumed by wildlife as well.

Most of the fruit is inedible shell and it is mostly hollow inside.   But the very middle has seeds and each seed is surrounded by a sack of juicy pulp and that is all you eat.  To be good they have to be dead ripe....we just pick up the ones that have fallen.  They don't stay long as the coons love them. 

Or make a sweetened drink from that juicy pulp.  Tropical passionfruit is one of my favorite flavors.  I just planted 2 maypop vines in hopes of getting fruit.  They can be invasive so be sure to gather all the fallen pods. 

They are nice. I grow them in 10 Gal pots , maybe i dont get a big crop but with 3 pots i am quite happy for the year. also dont forget to hand pollinate if no bees like in my balcony (maybe they are lazy ). 
lots of youtube videos about hand pollinating the flowers.
untill i didnt see the youtube tutorials i didnt understand why get the flowers but no fruit.

They are called maypops in South Carolina.They grow wild on my property and we love the taste.When they get soft and fall off the vine they kind of remind me of a large muscadine in taste.

Thanks for all the info all. Not sure where they came from but have several along the back fence as I went today for a closer look

I am growing 4 different kinds and very excited to put them in our green smoothies. Bonus you have them for free. There are hybrids to be found as well.

Greg around here they just grow wild.  When I was a kid road rite of ways and hedgerows fence rows and the like were not keep as clean as they are today.  There was always lot's of them growing wild and we just picked and ate while out playing.  Now a little harder to find growing wild but I do have some that came up in my back yard this year on a bank that doesn't get mowed often.  I love wild foods and fruits best of all.  No work and no worry just enjoy.

goss