Phylogenomics of the tribe Leonureae reveals a new genus: Paraleonurus (Lamiaceae, Lamioideae)

Abstract

With approximately 80 species across six genera (Leonurus, Lagopsis, Panzerina, Lagochilus, Chaiturus, and Loxocalyx), the tribe Leonureae represents one of the most morphologically diverse tribes within the subfamily Lamioideae of Lamiaceae. Previous studies indicated that Leonurus and Lagopsis are not monophyletic, and relationships among and within these genera remain unclear due to limited sampling and DNA markers. In this study, we present the most comprehensive phylogenomic analyses of Leonureae based on complete plastome sequences and 127 nuclear loci retrieved from next-generation sequencing data. Our results provide strong evidence for the monophyly of Leonureae, which can be further divided into six major clades. Consistent with previous studies, our analyses show that the traditionally defined Leonurus and Lagopsis are not monophyletic and should be reclassified. Consequently, we propose a new genus, Paraleonurus, along with six new combinations, based on molecular phylogenetic results and morphological evidence. The new genus differs from other genera of Leonureae by having palmately 3-lobed leaves, long spike-like verticillasters, inconspicuously 2-lipped calyces, and an emarginate middle lobe of the lower corolla lip.