Phylogeny of the Dorotheantheae (Aizoaceae), a tribe of succulent annuals

A revised classification of the Dorotheantheae tribe, endemic to South Africa's winter-rainfall region, reveals that the genus Cleretum encompasses all species previously assigned to both Cleretum and Dorotheanthus. Molecular analysis of plastid and nuclear sequences demonstrated that Dorotheanthus is monophyletic, while Cleretum is diphyletic, with two lyrate-leaved species closely related to Aethephyllum. This study proposes a single genus, Cleretum, comprising 14 recognized species, including two newly described subspecies elevated to species rank and two undescribed species. The research also highlights distinct climatic and edaphic niches occupied by major clades, suggesting potential shifts in breeding systems from large to small flowers. Additionally, it compares the distribution patterns of succulent annuals in Dorotheantheae with those in Mesembryanthemum (Aizoaceae) and Crassula (Crassulaceae), noting that while non-succulent annuals prefer arid areas, Dorotheantheae and Crassula show higher diversity in wetter regions, decreasing towards the arid Richtersveld and southern Namib.

Klak, C., & Bruyns, P. V. (2012). Phylogeny of the Dorotheantheae (Aizoaceae), a tribe of succulent annuals. Taxon, 61(2), 293–307. Portico. https://doi.org/10.1002/tax.612002