LAUSR

BACKGROUND AND AIMS Artemisia is a mega-diverse genus consisting of ca. 400 species. Despite its medicinal importance and ecological significance, a well-resolved phylogeny for global Artemisia, a natural generic delimitation and infrageneric taxonomy heretofore remain missing, owing to the obstructions from limited taxon sampling and insufficient information of DNA markers. Its morphological characters, like capitulum, life form, and leaf show marked variations, and are widely employed in its infrageneric taxonomy. However, their evolution within Artemisia are poorly understood. Here, we aim to reconstruct a well-resolved phylogeny for global Artemisia using phylogenomic approach, to infer the evolutionary patterns of its key morphological characters, and to update its circumscription and infrageneric taxonomy. METHODS We sampled 228 species (258 samples) of Artemisia and its allies from both fresh and herbarium collections covering all the subgenera and its main geographic areas, and conducted a phylogenomic analysis based on nuclear single nucleotide polymorphism (SNP) obtained from genome skimming data. Base on the phylogenetic framework, we inferred the possible evolutionary patterns of six key morphological characters widely used in its previous taxonomy. KEY RESULTS The genus Kaschgaria was revealed to be nested in Artemisia with strong support. A well-resolved phylogeny of Artemisia consisting of eight highly-supported clades was recovered, two of which were first identified. Most of the previously recognized subgenera were not supported as monophyletic. Evolutionary inferences of the six morphological characters showed that different states of these characters independently originated more than one time. CONCLUSIONS The circumscription of Artemisia is enlarged to include the genus Kaschgaria. The morphological characters traditionally used for the infrageneric taxonomy of Artemisia do not match the new phylogenetic tree. They experienced more complex evolutionary history than previously thought. We propose a revised infrageneric taxonomy of the newly circumscribed Artemisia with eight recognized subgenera to accommodate the new results.