Those are INCREDIBLE!!!! I Love the O. erinacea var. ursina... and the Pic of the O. polyacantha you posted was one I've drooled over many times!!! On that site though, it's listed as O. polyacantha (erinacea)... Not sure if they think they are one in the same or not.. but according to Benson, they do look similar. Dave Ferguson wrote that too! I'm gonna have to send him an email about that! O. polycantha var. trichophora is described in Bensons book as looking like the one in the picture on that link! Has very long hair like spines like O. erinacea var. ursina but are flattened. O. polycantha rufispina looks similar to O. erinacea var erinacea and along their distribution lines, the distinctions are minimal. O. erinacea also seems to usually have elongated pads where O. polyacantha has more round or oval pads... except in some varieties... So confusing! Thanks Caudex.... Just keep adding to my confusion ;-) Hey... shouldn't you be pruning some of your plants soon? :-D

I agree with my esteemed, everything-Aloe expert, pretty good with Sedums and Kalanchoes too, Canadian imported friend. Your Ferocactus number about 8 (look like Ferocactus latispinus) and are located on the bottom of the photo taken at the nursery. One easy way to find Feros is to run your fingernail along the largest spine. Just about every Fero has transverse ridges on it. This means the ridges run the short way on the spines. You will feel the ridges, even on species with straight spines like F. hystrix. If the spine is smooth, it likely is not a Fero.

ND Gal, And Trichocereus spachianus, a South American columnar, might be your columnar. I agree with the last three IDs. Feros come from the SW US and Mexico, as do (I think) Mammillarias (I don't think their range extends into Central America). So you have three plants from two hemispheres - yay! I'd separate them into their own pots, with drainage holes, porous soil, and even some top dressing, during the growing season, i.e. now.

Sam, sorry for reviving this old thread. Hope your plant is doing ok now. Given the point in time, I personally would take a sharp tool and scrape a sample off the dried up flesh to see if the tissue has rotted or it's still healthy and green.