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.
