Thanks, Kitty, yes i know about this draft, discussed this with @radekwalkowiak @choess and other iNat users. My personal view is, that differences are too weak for specific separation, populations of E. hyemale do differ a lot within Europe, Asia and North America, and i do suspect that intercontinental hybrids could be well fertile, as with crossings within species'.
Relatively minor genetic differences seem often to be over-valued, useful and diligent interpretation of gene sequences is at least the same important than to handle this tool.

@radekwalkowiak Once this swap is done, the synonymity will be built into the taxon description, so a search for or attempted use of Equisetum hymenale affine will result in the suggestion of the new taxon name. (I think it will also show up in brackets in searches, just not as the primary taxon name on the taxon's page.) The synonymy will also be noted on the Taxonomy tab for Equisetum praealtum once the swap is committed. I hope that addresses your concerns.

ok !

I've reversed the draft swap to swap praealtum into hyemale ssp. affine, which I think is the correct direction--comments should be modified before committing

agreed to keeping E. hyemale as single holartic species, but not to divide without covincing arguments. There seems to exist a mental, but no real barrier between "E." and "W."hemisphere, our aim is to overcome likewise boundaries of thinking and getting aware.