The collection of species from subtropical desert and semi-desert regions is comprised mainly of plants called succulents. These plants have fleshy organs that allow them to retain water especially well, an evolutionary trait aiding their survival during dry spells or in arid regions. These organs, producing structures that stabilize the plant, have developed in many different plant groups, and in addition to their function as water storage organs, they also allow for a more efficient production of biomass (CAM photosynthesis) in more extreme climatic conditions. In our collection, both Old-World and New-World succulents face each other, with the difference in growth forms clearly noticeable. Noteworthy is the convergent evolution of analogous growth forms by different plant groups that evolved in similar environmental conditions, albeit on different continents. In both New and Old-World taxa respectively, euphorbs and cacti, agave and the Aloe genus, and the Yucca genus and Dracaena trees, ecological challenges have been met with similar evolutionary solutions.
The succulent collection is currently housed next to the tropics greenhouse, until the planned succulent greenhouse is built.