I have heard that Stella reseeds so easily, that few people actually have the actual Stella. Between tissue culture and seedlings
My experience is when Stella sets seed with itself, the resulting seedlings look just like Stella. But, some of them did not rebloom, or bloomed in the foliage.
I figured they were seedlings because the were several inches from the clump, and none of the roots were intermixed, or connected.