If a species Sempervivum is grown in isolation and self-pollinates, then you would get seed that would be pure for that species. There would, of course, be some natural variety among the resulting plants.
If a hybrid Sempervivum variety is grown in isolation and is self-pollinated, then you would get plants that would also show variation among the resulting plants, but these plants would not be the same variety as the parents. Hybrid Sempervivum can have genetic contributions from many other varieties or species as part of their genetic makeup, some dominant, some not. Crossing hybrids allows for expression of many combinations of these hybrid traits, based on many factors, so the resulting plants could not be considered as "pure" copies of the original plants, even though some of them would be very close.
Genetics can be very complicated. It's not always a simple case of dominant and recessive genes. as there are other factors involved. That's why is is important to keep track of which varieties of semps are species and which are not. Note that the way names are expressed, if done properly, should tell you if the particular variety is a species or a hybrid. Species names are done in lower case. Hybrid names are in upper case. Thus, S. calcareum is a species, but S. Greenii is a hybrid or variety even though Greenii is a calcareum. This could also be expressed as S. calcareum Greenii.
Can't wait!
