Hi. This is definitely not my area of knowledge and didn't realize this
genus was so large and varied. I was under the impression all were of the
spiney persuasion, and much smaller plants than these obviously are. I
have the common C. johnstonii and have seen a couple others in years past
that were also spiney. So....you'll have to bear with my ignorance while
I learn about this interesting genus. I'm really surprised at the
towering size of these guys. Thanks for the info Julius.