Revised Taxonomy of the <i>Arctotis</i> Annual Clade (Arctotideae, Asteraceae) from Southern Africa: Integration of Molecular Phylogenetic and Morphological Evidence

Abstract— Previous phylogenetic analysis of ITS nrDNA sequence data for Arctotidinae species resolved a strongly supported clade containing all but one the showy annual Arctotis (informally designated Annual Clade). In present study, relationships in Clade were investigated by Bayesian inference and maximum parsimony analyses cpDNA ( trnT-trnL-trnF trnH-psbA ) (ITS) data. The phylogenies notably incongruent. venusta putative unnamed A. ‘sp. B’) as monophyletic both sets. monophyly leiocarpa was set, whereas remaining accessions formed poorly complex (the ‘ fastuosa complex’). Within complex, hirsuta with strong support phylogeny. A statistical parsimony-derived haplotype network five broad groups haplotypes showed no consistent geographical structure, species-specific lineages sp. B resolved. distributed among four groups. Incongruence between sets poor resolution within may reflect reticulate evolution, ancestral polymorphism, incomplete lineage sorting, tandem low information content greatest phenotypic diversification is cypsela morphology. Comparison morphology suggests general trend reduction sizes cypsela, abaxial wings, pappus scales, loss pubescence during diversification. revised taxonomy, integrating currently available evidence, accompanied full descriptive accounts key to taxa are presented. Eight recognized, including nomenclatural novelties chrysantha (sp. nov.) namibiensis nov.). names karasmontana , Venidium fugax macrocephalum lectotypified.