The Didiereaceae Family was named and described by Ludwig Adolph Timotheus Radlkofer in Naturlichen Pflanzenfamilien in 1896.
Plants of the World Online lists six accepted genera in this family of flowering plants. The Wikipedia only lists three subfamilies with a total of six genera with a combined 20 species. The 2013 version of The Plant List (no longer maintained) lists 7 species, so one was moved or absorbed.
The only species I have experience with were Portulacaria afra and Portulacaria afra f. variegata.
For more information about this family of plants, please click on the links below. The links take you directly to the information about the family.