Abstract
M.Sc.
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.