Regarding the original Q, i've always assumed incarnata to be self-pollinating, but to be honest, the gulf fritillary caterpillar, which seems to be able to pick out a single maypop plant from 100 miles away, is so darned efficient at locating (and eating) these things, that it wouldn't surprise me if the corresponding butterfly could pollinate pretty much any outdoor incarnata flower, regardless of how far away it was from its closest companion. It's utterly insane how fast these things find passionflowers.