<i>Elsholtzia yajiangensis</i> (Lamiaceae), a New Species From Sichuan, China

<i>Elsholtzia</i> Willd. is the largest genus in tribe Elsholtzieae (Lamiaceae) and has notable medicinal and economic value in East Asia. During a field survey in Sichuan Province, China, we discovered a morphologically distinct population of <i>Elsholtzia</i> resembling <i>E. lamprophylla</i> but differing in leaf size, indumentum, inflorescence type, and bract shape. To determine its taxonomic status, we conducted phylogenomic analyses using 1115 single-copy nuclear genes and 240 plastid loci from 45 accessions, representing major lineages of <i>Elsholtzia</i>. Both nuclear coalescent and concatenation-based trees consistently placed the new species in Clade I (<i>Ser. Fruticosae</i>) with strong support, while plastid data revealed a close relationship with several <i>Ser. Fruticosae</i> members, suggesting possible hybridization or incomplete lineage sorting. Morphometric analyses of 12 vegetative and floral traits clearly separated the new species from <i>E. lamprophylla</i>. Based on morphological and phylogenomic evidence, we describe it as <i>Elsholtzia yajiangensis</i> Y. Wang, L. J. Liu & Q. Wang, sp. nov. It is characterized by its secund spikes, broadly lanceolate bracts, strigose leaves with 5-7 lateral veins, and remotely obtuse-serrate margins. The species is currently known only from the type locality in Yajiang County, Sichuan, and is provisionally assessed as Data Deficient (DD) based on its narrow distribution and ongoing threats. This discovery highlights that the species diversity of <i>Elsholtzia</i> in the Hengduan Mountains remains underestimated.