Thanks everyone!

DaveW- this guy is going to live in the corner and get left alone! Thanks for sharing the link, very interesting reading.

Thanks teo! I think you might be right - you mean this thing is in the spurge family, and not a cactus at all? Crazy!

Hey folks, I have a large potted cactus that my grandma gave me years ago - it's been living at my parents' house, and it just recently came to my place. I have no idea where to start with cactus ID - can't find anything like a binary tree, which I've used to ID trees, plants, and mushrooms before. ...