WTF..not sure what to say about this.

[tudedude]

http://www.ebay.com/itm/321-DORSTENIA-g ... 3a82d492d8" onclick="window.open(this.href);return false;

a dorstenia grafted onto a cactus? Lol, yah it doesn't look like a fero stock, but what is it? That's ebay madness for ya.

[majcka]

I have my Adenium obesum grafted on an oleander. Nobody seems to care. Infact that is quite common I found out.

So why can't dorstenia?

[tudedude]

Ok after digging around the internet, I believe it's grafted onto a Dorstenia hildebrandtii, not a ferocactus.
Adenium and oleander kind of makes sense since they're from the same family. Their flowers looks so much alike too.

[phil_SK]

The pictures show that that isn't a cactus. This seller does have other items (cacti) grafted on Ferocactus so I'm guessing that it's a cut-and-paste error.

Grafts between families, certainly for succulents, are almost unheard of. I have seen a photo in an old British Cactus and Succulent Journal of one of the Didiereaceae grafted on Pereskiopsis but this family is close to the Cactaceae.