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Abstract
Alooideae (Asparagales–Asphodelaceae) currently comprises five genera, four of which are endemic to southern Africa. Despite their importance in commercial horticulture, evolutionary relationships among the genera are still incompletely understood, and the generic taxonomy remains unresolved. This study addresses generic delimitation in subfamily Alooideae using an expanded molecular dataset from three plastid regions (rbcLa, matK and trnH-psbA) and the first subunit of the nuclear ribosomal internal transcribed spacer (ITS1). Sequence data were analysed using maximum parsimony and bayesian statistics, and selected morphological traits were mapped onto the molecular phylogeny. Among the polytypic genera, only Astroloba and Gasteria were retrieved as monophyletic. Haworthia is shown to be polyphyletic and to comprise three main clades largely correllated with current subgeneric circumscriptions. The taxonomic implications of these findings are discussed.