Sandpaper Vein Flower

"WoW!" that's what I said when I saw these in bloom.
"Why have I not seen this flower before?"

It is apparently the Petrea Volubis or the common name, Sandpaper Vine, Bluebird Vine or Queen's Wreath. The whole flower is of great interest: petals-slightly rough, vibrant shades of purple and the vine is more like a bush (see extra photos).