Yes, my mother always said if I picked them I would wet the bed. The myth is so wide spread there must be an element of truth in it. perhaps they are good diretics? (I'm sorry, I don't think I can spell that one!)
What about the story that if buttercups reflect off your chin you like butter?
Is that not true?
A Carrion Crow in Dorset in July
A Puffin in Northumberland in June
Elderberries in my garden today