2.1 Crassula species
Nine species of Crassula native to southern Africa were used in this study (Table 1 ), spanning the breadth of the most recent phylogeny of the genus (Lu et al. 2022) and different growth forms and habitat preferences in southern Africa (Figs. 1, 2 ). The six species with compact growth forms (C. ausensis subsp.titanopsis , C. deceptor , C. fragarioides , C. plegmatoides , C. sericea var. sericea , C. tecta ) occur along the southwestern and western coasts of southern Africa, mainly within the predominantly winter-rainfall Succulent Karoo biome, whereas the three non-compact species (C. multicava subsp.multicava , C. ovata and C. perforata subsp.perforata ) occur along the southeastern and eastern coasts.