Gravenstein scion wood from 2024 that's been in the refrigerator. I saw a forum post mentioning they had some old scion wood that was callused up so I went and looked at mine and some of it was callused up so I stuck it in some water and put a bag over it the other day. It was already leafed out and I didn't expect those to turn green but they did. Wait and see if the callus grows roots.