I think this plant may be misidentified. It looks like an Oreocereus species rather than Cephalocereus, because the number of ribs is much lower than the 20-30 one would expect for the latter, there are long spines poking through the wool, and the growth habit is much less upright than I'm used to seeing for the Mexican "old man" cactus. Do you have any background info that might help sort this out, Lin?

Unfortunately I don't know what exactly to call it. I'm going to call upon a couple cactiphiles to see if they have opinions here -- paging @skopjecollection and @mcvansoest -- to help figure this out. If they don't have any better ideas then maybe we could file the image under the genus entry for Oreocereus.

Please let me know what you think. A group photo here for comparison of a few "old man" cacti:

Baja, I have no clue what it is ... someone identified it as C. senilis which is why the photo is at that database location. The photo isn't even that great and I don't mind if it's deleted.

The photo is great and the plant looks pretty old, so let's just figure out the best place for it. I'll sit tight until we hear back from the other members.

I think it is a member of the Orocereus family. Possibly: Orocereus doelzianus var. sericata aka Morawetzia sericata.

That is one that I have that looks similar, but aside from that I have only limited experience with Orocereus so it could easily be another one...

I took the photo when we were visiting California a few years ago, I think at Balboa Park but it may have been at the Point Loma area where we saw a bunch of spiny plants too. I'm from hot, humid Florida where most cacti don't grow so I'm not at all familiar with names for these types of plants. If someone knows the true identity, the photo can be moved to the correct database entry.

I have asked for the image to be moved to the genus entry for Oreocereus.