Materials and methods

Based on specimens and living plants collected from Hekou and Pingbian in Yunnan Province, morphological observations, measurements, and descriptions were conducted on 15 randomly selected living individuals per population. Traits assessed included growth habit, rhizome morphology, the presence of farina, leaf characteristics, calyx and corolla structure, and flower color. Comparative morphological analyses of allied species were conducted by examining living plants from their type localities and herbarium specimens from the online herbarium of the Royal Botanic Garden Edinburgh (E) and the online database of the Plant Science Data Centre (https://www.plantplus.cn/cn), as well as by reviewing the relevant literature (Hu 1990, 1994; Hu and Kelso 1996; Wu et al. 2013; Xu et al. 2017). Key morphological characters of living plants from the type locality of P. exserta were measured using digital calipers. The morphological characters of Primula membranifolia Franch., Primula mianyangensis G. Hao & C.M. Hu, and Primula pengzhouensis C.M. Hu, G. Hao & Y. Xu were obtained from living plants collected from their respective type localities and from their original descriptions (Hu 1990; Wu et al. 2013; Xu et al. 2017). The conservation status of the new species was assessed following the guidelines of the IUCN Red List Categories and Criteria (IUCN Standards & Petitions Committee 2024).