Recent phylogenentic studies of Crassulaceae indicate that Aichryson is closely related to Monanthes and Aeonium (both genera are also largely endemic to the Canary Islands).
The garden contains about 170 species of carnivorous plants, one of the largest such collections in Germany, as well as good collections of Euphorbia (300 species), Mediterranean plants (250 species), Haworthia and Aloe (65 species), as well as Aeonium, Conophyllum (40 species), Rhipsalis, and rare plants from Socotra.
In the Mascarenes, they are among the most diverse angiosperm groups, analogous to such (unrelated) plants as the aeoniums on the Canary Islands or the silversword alliance of the Hawaiian Islands.
Morphologically, they are closely linked with the genera Jovibarba, Aeonium, Greenovia, Aichryson, and Monanthes, occurring mainly in Macaronesia (Azores, Canary Islands, Cape Verde, Madeira).