Discocactus placentiformis

This is a fairly young plant of Discocactus placentiformis (syn: D. crystallophilus) in our greenhouse. Their natural habitat is Minas Gerais, Brazil, where they are fairly widespread. As much as Lynn-Marie and I enjoy this genus, we shied away from them for many years when we didn't have an adequate greenhouse or space with adequate light in the house. They're a little touchy when it comes to our wet and chilly winters. But given a nighttime temperature of 50F or more during the winter, they're very rewarding. And like I said, I'm a sucker for plants with woolly tops...