Yes, astrophytum ornatum.

Most naturally do that (crust at the bottom) but other seem to get fatter and grow into a nice green column. I have one doing the fattening, and two staying skinny and growing like this. (Both with nearly exactly the same conditions.)

If you want, you can cut at that point (i would do it a bit lower), dust with cinnamon powder or a rerooting hormone, and let callous over for about a week-2 weeks. And then plant in a nicely draining soil and mist every-so-often. You wait wait till for the chance of rerooting to be higher. Keep the bottom because it might sprout out little babies.

I would definitely cut it lower. Close to where it is at its narrowest. That will give you a bit to anchor it in the ground, and it will still look like a well formed ball.

Thanks guys. This will be my project tomorrow.

So is the gray crusty skin from too much sun, or just from age, or too little water, or what? How can I prevent this with my new astrophytum? It's been growing in full southern california sun, and I don't grow it under any shade at the moment.

It just grows there naturally. Think of it sort of like tree bark. And, i dont really think there is a way to stop it, besides pampering it like a baby (perfect light, water, and soil)

Robin,

What's being spoken of as crust is corking, and it's natural on this species, whether it's a show plant or one in the field. I would not cut it, because I like it, but if I were to cut it, I'd wait until there are warmer ambient temps - cuttings roots better and wounds seal more quickly in the spring / summer.

Thanks cactusmcharris. This is probably not a show worthy plant so I might practice cutting it and rooting it. But I will wait until the winter is over, like you said, for better success. Thanks again! /Robin