M.conzatii

I bought this at last years Sheffield branch show (2013)

M. conzattii is a synonym of M. karwinskiana, and though it is supposed to have rather more angled tubercles than M. karwinskiana, there seems little to suggest it is actually any different.

M. karwinskiana is a pretty variable species, and has had a number of separate re-descriptions because of this, but none really stand up to scrutiny.

The older description of M. karwinskiana (1832) clearly predates that of M. conzattii (1923) so though the name might linger, unless you know the plant's pedigree, M. conzattii for it is probably best discarded.

Hi Chris
Thanks for your reply.
The plant was named by a previous owner and I believe formed part of a collection that was inherited by the Sheffield branch.