This one is Ranunculus ficaria 'Coppernob' and is about 5 in / 13 cm from the base of the pot to the top of the flower. Still it's one of those invasive buttercups given half a chance. The leaves are a bronze / dark green colour, similar to Brazen Hussy and the other bronze varieties.
This one propagates itself freely so if you want one, leave me a comment.
Mike hates these guys - well they are close to the nec plus ultra of invasion.
Pot is by Bryan Albright; glazed only at the rim, colour is sort of a light tan with hints of green. The pot does not self-propagate, so I'm not giving any of them out. In fact, a few pots have met their demise here, due to territorial disputes among the neighbourhood cats. And we have marauding blackbirds.
The joys of bonsai growing...