Macrocentra said:
I'm actually not sure yet. Hoping someone here might have an idea what it is. I'd love to find out. It was such a cool find!
That is Mammillaria spinosissima if I am looking at the right 2nd and 3rd picture (the pot with the 3 cacti trailing out of it). You can find picture where people are growing them out of the bottom of hanging baskets (I tried with mine, after it had grown so long and heavy that it had managed to grow itself out of the hanging basket it was in, but it was not a success and all the messing with the plant did end up killing it).
These are often found on slopes, rooted in rock crevices, trailing downwards. They are great, but at that size they are becoming harder to handle especially if you need to move the pot around a lot because of the climate you are in.
