DaisyI said:
I suspect your Euphorbia is lactea 'White ghost' and is attempting to revert. I have a crested version doing the very same thing. I've thought about cutting and rooting that piece to see if it stays two tone or reverts to white or green.
Your Prickly Pears are very nice - very well grown. But nothing with pokies! Where is the Opuntia microdasys? Or Opuntia erinacea? Or some nice poky Cholla?
Prickly Pear and all their relatives will root on any part of a pad or stem. I spent one year planting them upside down, right side up, on one edge, burying the entire pad or not burying any of the pad. I have had them grow roots sitting on a paper plate in my kitchen.
I am attaching a photo of a Snow Leopard Cholla baby with a little barrel cactus buddy (I reused soil). You can always tell the difference between a Opuntioid and a barrel cactus. I imagine you can tell the difference between all the cactus groups by looking at seedlings.