Well, THIS is unexpected!
Look what popped out on my incarnata the other day:
A white "Alba" sport. Shocked the heck out of me, I can tell you. The flower was looking a little ragged, so I suspect that it actually bloomed the day before, but had stayed open a second day as well. The ovary was very under developed and the stigmas hadn't reflexed, so the flower was sterile. The flower itself was 2.5" in diameter. For comparison, here's a pic of what a "normal" flower on this vine looks like:
These things measure up to 4" across, so the white sport differs significantly. Neither the flowers that bloomed on that particular vine ahead of the white sport, nor the ones that have bloomed after it show any hints of white. This one, apparently, was a one-off.
And just for funsies, here's a pic of some of the fruit I have maturing on the plant right now.