The genus Primula is extremely diverse in the east Himalaya-Hengduan Mountains (HHM) in China as a result of rapid radiation. In order to overcome the difficulty of morphological classification of this genus, we surveyed three plastid regions (rbcL, matK, and trnH-psbA) and two nuclear markers (ITS and ITS2) from 227 accessions representing 66 Primula species across 18 sections, to assess their discriminatory power as barcodes. We found that ITS alone or combined with plastid regions showed the best discrimination across different infrageneric ranks and at species level. We suggest rbcL + matK + ITS as the first choice at present to barcode Primula plants. Although the present barcoding combination performed poorly in many closely related species of Primula, it still provided many new insights into current Primula taxonomy, such as the underlying presence of cryptic species, and several potential improper taxonomic treatments. DNA barcoding is one useful technique in the integrative taxonomy of the genus Primula, but it still requires further efforts to improve its effectiveness in some taxonomically challenging groups.

Species-rich genusPrimulaL. is a typical plant group with which to understand genetic variance between species in different levels of relationships. Chloroplast genome sequences are used to be the information resource for quantifying this difference and reconstructing evolutionary history. In this study, we reported the complete chloroplast genome sequence ofPrimula sinensisand compared it with other related species. This genome of chloroplast showed a typical circular quadripartite structure with 150,859 bp in sequence length consisting of 37.2% GC base. Two inverted repeated regions (25,535 bp) were separated by a large single-copy region (82,064 bp) and a small single-copy region (17,725 bp). The genome consists of 112 genes, including 78 protein-coding genes, 30 tRNA genes and four rRNA genes. Among them, seven coding genes, seven tRNA genes and four rRNA genes have two copies due to their locations in the IR regions. TheaccDandinfAgenes lacking intact open reading frames (ORF) were identified as pseudogenes. SSR and sequence variation analyses were also performed on the plastome ofPrimula sinensis, comparing with another available plastome ofP. poissonii. The four most variable regions,rpl36–rps8,rps16–trnQ,trnH–psbAandndhC–trnV, were identified. Phylogenetic relationship estimates using three sub-datasets extracted from a matrix of 57 protein-coding gene sequences showed the identical result that was consistent with previous studies. A transcript found fromP. sinensistranscriptome showed a high similarity to plastidaccDfunctional region and was identified as a putative plastid transit peptide at the N-terminal region. The result strongly suggested that plastidaccDhas been functionally transferred to the nucleus inP. sinensis.

Primula dejuniana G. Hao, C.M. Hu & Y. Xu sp. nova (Primulaceae) is described and illustrated from Sichuan, China. In general morphology it is clearly related to the section Petiolares subsection Davidii, which is characterized by firmly papery or leathery leaves, with veins impressed adaxially, often prominently raised and alveolate abaxially. The new species is similar to P. davidii in the indumentum and to P. tenuituba in the slender long corolla tube, but can be easily distinguished from all other species in this subsection by its leaves with an acute-apiculate apex and a sharp dentate margin.

Current and historical events have both affected the current distribution patterns and intraspecific divergence of plants. While numerous studies have focused on the Qinghai-Tibetan Plateau (QTP), the impacts of such events on the flora of subtropical China remain poorly understood. Subtropical China is famous for its highly complex topography and the limited impact from glaciation during the Pleistocene; this may have resulted in a different genetic legacy for species in this region compared to fully glaciated areas. We used plastid and nuclear DNA sequence data and distribution modeling to analyze the divergence patterns and demographic history of Primula obconica Hance, a widespread herbaceous montane species in subtropical China. The phylogenetic analysis revealed two major lineages (lineage A and lineage B), representing a west-east split into the Yunnan and Eastern groups, and the Sichuan and Central groups, respectively. The Eastern and Central groups comprised relatively new derived haplotypes. Nested Clade Analysis and Bayesian Skyline Plot analyses both indicated that P. obconica mainly experienced a gradual expansion of populations. In addition, the simulated distribution of P. obconica during the Last Glacial Maximum was slightly larger than its present-day distribution. Our results are the first to identify a west-east migration of P. obconica. The gradual expansion pattern and a larger potential distribution range in cold periods detected for P. obconica indicate that the population expansion of this species is consistent with the phalanx model. In addition, the current patterns of genetic differentiation have persisted as a result of the extensive environmental heterogeneity that exists in subtropical China.

A new species, Primula pengzhouensis (Primulaceae), from central Sichuan, China, is described and illustrated. It is assigned to Primula sect. Aleuritia subsect. Yunnanensis, and is most similar to P. socialis, but can be easily distinguished from that species by its much larger flower and elliptic or ovate-elliptic leaves.