There are over 2000 different Euphorbia, and that doesn't include cultivars. I have several that I lost contact with tags/names and have struggled to rename. It is pretty common for one to come into production and then become rare to find because it is "replaced" with a suposed superior plant that is very similar. Good luck.
By the way Beecmcbeil, those aren't two plants in the pot. That is the leaf and bract (looks like bloom) of the Euphorbia.