This flower/weed grows on a vine that wraps around one of the porch columns. We've been in our house for 4 years now, and last spring was the first time I ever saw it. It just bloomed again today.
Neither I nor google nor any of my flower ID guides knows what this interesting flora is. But I know I love the purple color!
So if you know, please enlighten us! :)
UPDATE: I found an answer! Actually the ladies--who know everything!--on a homeschool message board I frequent passed along the answer. One of the moms even posted a link describing the symbolism of this flower. The passion part of the name was given by Spainish Catholics hundreds of years ago as a way to describe the cruxifiction of Christ. The beautiful purple radials represent the Crown of Thorns and the top 3 stigma represent the nails.
Explanation aside, I look at its rich colors and am awed by the creativity of the Creator. When I really start to focus on the new life around us, even dandelions amaze me! I may be a novice at identifying flowers (and don't get me started on my embarrassing ineptitude of naming trees), but I so enjoy looking at them with my kids--who never seem to miss a single amazing one. They love the very nature that I have taken for granted for so long. :)