Curio crassulifolius used to be one of more than 1000 Senecio species in the world. There is an issue with the spelling of the specific epithet: some records have it as crassulaefolius, apparently the same plant. Both names indicate leaf resemblance with Crassula. Maybe one will encounter a Crassula with such leaves one day. Time brings either progress or a return to chaos; we'll see, those of us who may be still around.
The picture was taken at Kirstenbosch. The species name was found in the Bartholomeusklip Plant List (a reserve to the north of Wellington in the Boland), although no clear indication could be determined of the species distribution.
The leaves are fleshy, cylindrical and spindle-shaped, pointing upwards and inwards in attractive rosette-like clusters around the tops of the branched stems. Leaf colour is blue-green or green to yellow-green when older. The flowers are yellow and occur in clusters above the leaves (Wikipedia; www.redlist.sanbi.org).