Here it is, my perfect flower:
It's kitabelia 'Chalice', and it's the most beautiful flower I think. I grew the plant quite a few years ago now, from seed and it thrives in my garden, beside a small white rose, and near to the path so I can see it every time I pass. I love the freshness of the colours - simple white with bright emerald green. It flowers on untilo teh first frost, followed by generous seed heads.
I think there is at elast one other variety of kitabelia, but I need to do some more research.
It would have to go some to beat this beauty, though. What do you think?