Buttercups

My friend Eve gave me these flowers to transplant. She got them from my other friend Hapi. Hapi got them from another friend named John who is now deceased. Hapi says they are called Buttercups. I don't know. Aunt Sue do you know? Aunt Sue loves flowers and I read her blog Sue's News faithfully. Hopefully Aunt Sue can tell me more about this flower that has made quite a journey.