Primula xideensis (Primulaceae), a New Species from Sichuan, China, Based on Morphological and Molecular Evidence

We document and illustrate Primula xideensis, a new species collected from Xide County, Sichuan Province, China. Morphologically, it resembles P. stenocalyx, P. farinosa s.l., and P. pulchella, but differs by its roots densely covered with multicellular hairs; elliptic to obovate leaves with non-revolute, irregularly and deeply dentate margins, both surfaces efarinose, shortly hairy, and scabrous; tubular calyx parted to the middle; corolla mouth densely white-farinose; stamens positioned at mid-corolla tube in pin flowers and near the throat in thrum flowers; styles reciprocally placed; and an oblong capsule shorter than the persistent calyx. To clarify its phylogenetic placement, we constructed phylogenetic trees using two datasets: 63 complete chloroplast genome sequences and 75 nuclear ribosomal DNA internal transcribed spacer (nrITS) sequences. Both trees showed similar topologies, consistently placing the new species within a monophyletic group of Sect. Aleuritia, supporting its assignment to this section. For a deeper comparison between the new species and other members of Sect. Aleuritia, we incorporated chloroplast genomes of seven additional species from this section. The results revealed highly conserved chloroplast genomes among all eight species, with only minor differences between the new species and the others. Primula xideensis is currently known only from its type locality. Based on IUCN Red List criteria, its conservation status is assessed as Data Deficient (DD).