Yeah,
I guess I see it as kinda like correcting someone when they ask for a 'Kleenex'...no you cannot have one, you may have a facial tissue though, specifically, in this case you may have an 'Envision'...
And really, it is not that I don't care about the names of plants--I do, but if someone calls a sunflower a daisy I am pretty hard-pressed to figure out which daisy 'owns' the common name of daisy, such that I can float a legitimate assertion that a sunflower cannot be called a daisy.
And in the case of
Schlumbergera, I find it hilarious that
S. truncata is, for all intents and purposes the 'new' Christmas cactus--whether we like it or not--precisely because it does bloom around Christmas and it is widely grown and available for people to acquire as the Christmas cactus, and yet folks insist on disabusing folks of that notion, just because some other rare and hard to find
Schlumbergera was the original Christmas cactus, or the so-called 'true' Christmas cactus.
Therefore, we cannot call a different species in the same genus the same common name...really? Why not? We do it all the time with other plants.
Take
Salvia, for example, huge genus, many species, and pretty much we get to call them sage; and there are many distinguishable common names to use; and they do span species i.e. 'autumn sage' is not limited to a single species representing the original, or the one and only 'true' autumn sage. It would be an equally ridiculous construct if there was a rare and hard to find species that could only be called the autumn sage and all the other species which were mass-marketed had to be called the late summer sage, or seasonal sage, or something else because 'autumn sage' was revered and reserved.
Now if Sondra had posted her pictures and said "here are my
Schlumbergera russelliana", then I could totally be supportive of the correction that the plants are in fact
Schlumbergera truncata instead, because then we would be talking about the actual identity of the plants, using their names.