Towards an understanding of the taxonomy of the Eurasian montane riparian genus Myricaria (Tamaricaceae) through Angiosperms353 herbariomics

Myricaria Desv. (Tamaricaceae) is a genus of shrubs that play a keystone role in montane riparian ecosystems across Eurasia, shaping riverine habitats and supporting ecological function. The genus has a centre of origin in the Qinghai-Tibetan Plateau and exhibits a broad distribution, but many species boundaries are unresolved. Here, we present the first phylogenomic analysis of Myricaria using the Angiosperms353 target enrichment bait set, with sampling across its full geographic range. Off-target plastid loci were extracted from next-generation sequencing data using the CAPTUS bioinformatics pipeline. We infer species relationships using ASTRAL-IV and network analysis with SplitsTree, in conjunction with morphology. We also provide a taxonomic treatment of the genus, integrating our morphological observations and phylogenomic analyses for species delimitations. Based on our analyses, recognise two infrageneric sections: sect. Parallelantherae (containing only M. elegans) and sect. Myricaria (the remainder of the genus, with type species M. germanica). We also propose synonymising M. davurica, M. bracteata and M. squamosa with M. germanica. Although species boundaries in the Asian highlands remain unresolved, we conclude that the species M. elegans, M. germanica, M. laxiflora, M. longifolia, M. platyphylla, and M. pulcherrima are well-supported both phylogenomically and morphologically.