Nigella Damascena flowers at various stages.
My neighbor dug up a plant from her yard for me and this Nigella plant came along. The stems are about 2 feet high and the flowers are about 1.5 inches across. The buds open as white flowers which then change into several shades of blue ending in a dark blue. I've seen the seed pods in my neighbor's yard and they are fascinating so I look foward to photographing them too.
See http://www.hort.wisc.edu/mastergardener/Features/flowers/nigella/nigella.htm for more information.