Thank you, Chris. It's really intriguing how so many Mammillaria made it into my very un-specialized collection of plants. I remember buying in bulk twice - one batch of some thirty plants from an eBay seller in Germany and another time from Amante Darmanin. Still, that would only account for about half of the 140 or so Mammillaria I have recorded, with a lot more to come when the seedlings make it into the "general population"...