I am unconvinced that the notorious random-splatter artist known as Chance came up with this. But what do I know? I'm just a clump of cells expelled from its birth-persyn's swampy interior to act as the accidental catalyst of other clump-expulsions. (note to self: add "And I Vote!" to the bumper sticker.)
They adorn creeping vines that share the forest floor with their even-more aggressively creeping cousins, poison ivy, muscadine, greenbriar, kudzu, and their ilk. This one was growing at the bottom of the pond dam near the outlet stream where the rows of trees start. They don't seem too picky about zip code; they pop up down by the streams and up on the hillsides, but never, it seems, in great abundance, the way honeysuckle does sometimes.
Though it seems quite unnatural for a human eye to be unattracted to this sort of thing, dogs couldn't care less about them--as beautiful things, I mean. Don't notice them, might pee on them if they're in the right place, but won't seek them out for that. Don't eat them, even though they can hardly say "no" to a choice blade of grass. As much as I love dogs, I don't think they have the same aesthetics as we have. Then again, when I'm on the tractor mowing down the underbrush choking the rows of pines, I don't try to steer around passion flowers any more than I do poison ivy or privet.
I believe they're also called Maypops. Have you ever seen one out in the woods?