The following link was found on another site and points to an effort to list the proper names for all plant species. As such, it assigns some judgments about which names are proper and which names may not be the formal, correct names for plant species.
http://www.theplantlist.org./
Of interest to us here:
Jovibarba heuffelii is a synonym and is likely more properly called "Sempervivum heuffelii"
The "Jovibarba hirta" species, along with several other Jovibarba species, appear to be more properly named as subspecies of "Sempervivum globiferum" e.g. "Jovibarba hirta" is a synonym for "Sempervivum globiferum subsp. hirtum"; Jovibarba allionii is a synonym for "Sempervivum globiferum subsp. allionii" and there are many more.
It will be interesting to see how this effort is accepted by the scientific community and whether it helps hobbyists to get proper names on a lot of plants. Note that the list does not make an effort to sort out varietal names, which is likely an impossible task.
However, you can use this list to get an idea of just how many species of Sempervivum and related plants there are. Just count the accepted names on the list for a good idea.
Recommended for those who want to learn more.
