Hi guys, long time lurker who finally registered. I recently moved in with a buddy and he has this puppy growing right out in our front yard... http://imgur.com/a/yDFa6 All these pics are of the same cactus, different arms have different ribs, varying from 4 - 6, it looks like it hasn't gotten any water except that from the rain during the summer. My buddy says it was there when he bought the place, and the longest arm is probably 7 -7.5 ft (haven't actually measured). Could anyone help me id this cactus? Cheers, HH