Mammillaria bertholdii has been described in the 2/2014 issue of the AfM journal.
It is a plant from Oaxaca, which has tubercles similar to Pelecyphora asseliformis or Mammillaria pectinifera, and flowers like Mammillaria saboe. It is placed by its author, Thomas Linzen, in the Series Longiflora, and questions whether intermediate plants might be found between the Saboe group in northern Mexico and the Napina group in southern Mexico.
It would appear to be yet one more fascinating and rare discovery of new Mammillarias in Mexico.
_________________
Chris43, moderator