okay i wanted to try grafting a cacti to a stapelia, this is my first time in grafting and i have obtained all necessary knowledge regarding cactus grafting. I wanted to try grafting one of the mammillaria pups to my stapelia, mammillaria as the scion and stapelia as the root stock. I bought this stapelia because i thpuht it was a cactus but turns out not, so i figured by grafting a cactus onto it, it ewould be valid to call it cacti. thank yoh for your response :D