I was given a cutting of a friend's cactus. It is growing in his front yard but he does not know much about it. His cacti are green and segmented some with red bulbs on top. I believe the red bulbs were fruit, not unopened flowers. All segments of the cactus (like the segment I was given as a cutting) have patches thick with spines which would stick to skin on touch as you can see in the picture:
Most of the pads were larger than the one pictured. It is only about 3 inches in diameter, while some of the pads were much larger than that. But they all generally had the same shape, generally flat with a slight curve, rounded, and segmented. His plants stood a little more than 3 feet off of the ground at max height.
I am located on central part of the east coast (USA) near the ocean.