as I wrote elsewhere all the x nixonii are Jovibarbas at your definition at ATP; so this plant has to be slided to the database of Jovibarba;

all the globiferum-species are Jovibarbas equally...

so it has to be

Jovibarba x kwediana
Jovibarba x mitchellii
Jovibarba x smithii
Jovibarba x nixonii

and "all four forms are a cross between Jovibarba globiferum x Jovibarba heuffelii"

in newer time the hybrid-name "x nixonii" become a topic for all those crosses; so I suggest to call them Jovibarba x nixonii (x kwediana) etc.

Thank you Peter. I think I made all the corrections in the Sempervivum database and moved all the globiferum to Jovibarba.

then your sectioning is tidy