Date: 1997 March 21
This is a species that the taxonomists seem never to have made up
their mind about. I'm using the name from my plant label, but you
can also choose Mammillaria (or Porfiria) schwartzii,
not to be confused with M. schwarzii which is something else
entirely. I grew this plant from seed sown around 1985. It has thick
tuberous roots, and tends to be a bit temperamental in cultivation -
I had two plants until a few months ago when one rotted!