As far as I'm aware, they're all members of the genus Crassula. The primary species is known by several different scientific names: Crassula ovata, Crassula argentea, Crassula obliqua, Crassula portulacea, Crassula arborescens
. There are multiple names because scientific nomenclature is currently undergoing many changes as a result of the study of DNA. There is no one 'authority' that decrees which name shall be used the world over.
In addition, there are many different 'types', if you will, usually referred to as 'varieties', 'hybrids', or 'cultivars', all of which mean basically the same thing. That is what gives us the great variation you see among individual plants, but they're still all commonly called Jade plants. It's the same sort of thing as the domestic dog. They're all classified as Canis lupus familiaris
, whether Chihuahua or Great Dane. But there are many different breeds
, all of which have unique traits. We still call them all 'dogs', though.
It's for this reason that I usually ask members to post a picture of their particular
plant. The care of all Jade plants is pretty much the same, though, regardless of the particular hybrid involved.
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams