Euphorbia lactea crested variegate graft

The colors on these can be quite variable. This one has some of the most outstanding reds I've ever seen. These are always grafted, as the lack of chlorophyll inevitably would lead to an early death if grown on their own roots. The multicolored part on top is called the "scion" and the green section it's grafted onto is called the "stock". This one seems to be grafted onto adequate stock, but the problem with some of these popular grafts is that the stock isn't adequate for the scion as it grows to a mature plant. At that point it sometimes needs to be re-grafted.