Board Thread:Question and Answer/@comment-74.209.6.180-20151218001136/@comment-25158302-20160126180237

You can only use the base card for an amalgamation if that is what it calls for.

However, there are some amalgamations that call for evolved cards, usually UR cards for events.

For example:

Jean (UR) can be amalgamated by combining Kathleen (HSR) and Junior Director (HSR) but NOT their base cards. So this is another reason you should try your best to get as many of the archwitch drops as possible during an event.

I made the mistake of not trying as hard once I received one of the drops, and now I have some cards cluttering up my inventory that I can never amalgamate! Boooo!