Kingcups.

Also known as Marsh Marigold ( Caltha palustris ). 
In fact it has a large regional variation of common names.
One of its names is Mollyblobs and amusingly this is the Blip name of one of the blippers I follow. She has one of the best natural history blip sites..

I did wonder about saving this to blip on May 6th. but it will almost certainly be over by then.