The evolutionary origin and taxonomic position of Dendroseris and Thamnoseris (Cichorieae, Asteraceae) are discussed in the light of recent molecular systematic studies. Based on the previous development of a robust phylogenetic framework, we support the inclusion of the group as a subgenus integrated within a new and broad concept of the genus Sonchus. This approach retains information on the evolutionary relationships of the group which most likely originated from an adaptive radiation process; furthermore, it also promotes holophyly in the subtribe Hyoseridinae (formerly Sonchinae). Consequently, all the former Dendroseris and Thamnoseris species must be transferred to Sonchus. A preliminary nomenclatural synopsis of the proposed subgenus is given here, including the new required combinations.