Primula pingwuensis (Primulaceae), a new species in Primula sect. Auganthus from Sichuan, China.

Abstract

Primula pingwuensis sp. nov., a new species of Primula sect. Auganthus from Sichuan, China, is described. It resembles P. sinensis in having palmately lobed leaves and multi-whorled inflorescences but differs by its multi-branched stems, more densely short-pubescent surfaces, thicker chartaceous leaves, narrower leaf blades, and indistinct translucent nectar guides. A taxonomic key covering all nine known species of Primula sect. Auganthus is compiled herein to support field morphological discrimination. A chloroplast genome-based phylogeny shows that P. pingwuensis is sister to P. rongrong, and this clade is sister to P. fujiangensis. Incongruence between morphology and molecular phylogeny is observed within the section. Leaf-lobing patterns have undergone multiple independent evolutionary transitions during adaptive radiation in karst habitats, indicating that a few morphological traits cannot be used to reliably infer interspecific relationships. The new species is assessed as Data Deficient (DD) following IUCN criteria, owing to the lack of long-term observations of its threat status and population dynamics. This study provides new data for the taxonomy and evolution of Primula sect. Auganthus.