Backeberg, Curt (1894–1966)—author of Die Cactaceae (in six volumes 1958–62) condensed into Das Kakteenlexikon (one volume, 1966) and describer of many new cactus genera and species.
Adanson, Michel (1727–1806)—colonial discoverer of the genus Adansonia, the Baobab tree, which is named in his honor and describer of the genus Kalanchoe, among others.