There is one species of Anemonella (thus it is a monotypic genus), which grows in the eastern half of North America, spreading west as far as Kansas and Ontario. However there are now over 30 cultivated forms, with varying colours and numbers of petals. Either way it is a delicate spring flowering perennial, going dormant in summer. It needs a loose, leafy soil, in shade, whether that's in a rock garden setting, in a pot or under a deciduous shrub or tree. A little gem.