From Madrid public greenhouse

Identified as Mammillaria gracilis. I think it isn't.

Regards,

Much more like M. carmenae to me. Not gracilis. Its a shame but I have rarely seen a "municipal" collection without at least 1 missing or wrong name. I think its because most don;t have anyone who really knows about cacti, and labels get mixed, not corrected, and so it goes on.

Thank you Chris. Yes, is a pity such a big number of misidentifications in botanical gardens and public greenhouses. Most of the people are not going to notice so managers don't pay any attention to the problem.

Looks more like M. laui than M. carmenae, but laui has red flowers and carmenae whitish/yellowish. Therefore, it is probably one of those hybrids that you see so much nowadays.

Wolter ten Hoeve.

Thank you again Wolter.