Snakeshead fritillary ( Fritillaria meleagris )

A quiet day round home.  Finally the Fritillaries are in flower.  I have seen blips of them from further south for a while.  

The pale bud towards the bottom of the picture is, I think, going to be one of the white ones.  The white ones are a bit of a mystery.  We only planted the traditional coloured ones, admittedly several decades ago.  During that time the flowers have increased in number and "walked about a yard from the original site.  The whites have toof occurred for one of two reasons.  Fritillaries mutate easily? I very much doubt it or there would be more variations.  So my second suggestion is that the white gene is a recessive gene and somewhere over the years gametes with the recessive gene have produced the first white flowers.  The rest as they say would be history.