that was the name on the label it came with, of course you're right! s. purpurea is also said to resemble neowerdermannia vorwerkii which this plant doesn't really do neither, guess I'll have to put it up for ID....
today was a milestone, my first seed to flower experience! gymnocalicium erinaceum
quite a coincidence, this plant came from you hob! rebutia einsteinii MN100
echinocereus scheerii ssp. gentryi
With apologies to the late Professor C. D. Darlington the following misquotation springs to
mind ‘cactus taxonomy is the pursuit of the impossible by the incompetent’ - Fearn & Pearcy, Rebutia (1981)