The complex evolutionary history of Capparis L. (Capparaceae Juss.) in Australia, and the description of five new species and two new subspecies

Capparis comprises ~145 species, of which ~21 occur in Australia; however, the relationships and taxonomic status of Australian Capparis taxa remain to be tested. We present phylogenies of all Australian Capparis taxa by analysing Angiosperms353 loci using coalescent and concatenated approaches. All trees resolve Capparis as monophyletic, with a whole-genome duplication (WGD) event detected at the crown. Capparis sect. Capparis and sect. Busbeckea are monophyletic but sect. Monostichocalyx is non-monophyletic. The relationships of species within sect. Busbeckea are poorly supported due to rapid radiation following ancient WGD. The relationships of taxa within sect. Capparis and the clades of sect. Monostichocalyx are well supported, with some incomplete lineage sorting. Capparis spinosa is geographically, morphologically and phylogenetically structured across northern Australia. Based on these results, we describe five new species and two new subspecies of Capparis, bringing the total number of species in Australia to 26. Capparis xylocarpa, C. megacarpa, C. loxophleba and C. splendidissima are newly described. Capparis loranthifolia var. bancroftii is raised to species level as C. bancroftii. Capparis spinosa subsp. nummularia is re-circumscribed, and two new subspecies, C. spinosa subsp. formicosa and C. spinosa subsp. insularis are described. We provide a key for all Australian taxa.