In my limited experience Mark, Buttercups like a scone with jam.
Your seed looks lovely and I hope it germinates like mad. We don't seem to get seed here, or not that I've seen. Seed sent to our lists is always tiny and never fertile (of calandrinioides, I mean) so best of luck with it Do you have 2 clones and so have cross pollination? I've wondered if that's the problem here, most plants if not all, being from a single, divided source.