Chinese lacquer tree (Toxicodendron vernicifluum) is an important commercial arbor species widely cultivated in East Asia for producing highly durable lacquer. Here, we sequenced and analyzed the complete chloroplast (cp) genome of T. vernicifluum and reconstructed the phylogeny of Sapindales based on 52 cp genomes of six families. The plastome of T. vernicifluum is 159,571 bp in length, including a pair of inverted repeats (IRs) of 26,511 bp, separated by a large single-copy (LSC) region of 87,475 bp and a small single-copy (SSC) region of 19,074 bp. A total of 126 genes were identified, of which 81 are protein-coding genes, 37 are transfer RNA genes, and eight are ribosomal RNA genes. Forty-nine mononucleotide microsatellites, one dinucleotide microsatellite, two complex microsatellites, and 49 long repeats were determined. Structural differences such as inversion variation in LSC and gene loss in IR were detected across cp genomes of the six genera in Anacardiaceae. Phylogenetic analyses revealed that the genus Toxicodendron is closely related to Pistacia and Rhus. The phylogenetic relationships of the six families in Sapindales were well resolved. Overall, this study providing complete cp genome resources will be beneficial for determining potential molecular markers and evolutionary patterns of T. vernicifluum and its closely related species.

Shared ancestral polymorphism and introgression are two main causes of chloroplast DNA (cpDNA) haplotype sharing among closely related angiosperms. In this study, we explored the roles of these two processes in shaping the phylogeographic patterns of East Asian Cerris oaks by examining the geographic distributions of randomly and locally distributed shared haplotypes, which coincide with the expectations of shared ancestry and introgression, respectively. We sequenced 1340 bp of non‐coding cpDNA from Quercus acutissima ( n = 418) and Q. chenii ( n = 183) and compiled previously published sequence data of Q. variabilis ( n = 439). The phylogenetic relationships among haplotypes were examined using a median‐joining network. The geographic patterns of interspecifically shared haplotypes were assessed to test whether nearby populations have a higher degree of interspecific cpDNA sharing than distant ones. We identified a total of 27 haplotypes that were grouped into three non‐species‐specific lineages with overlapping distributions. Ancestral haplotypes were extensively shared and randomly distributed across populations of the three species. Some young haplotypes were locally shared in mountainous areas that may have been shared refugia. The local exchange of cpDNA resulted in an excess of similar haplotypes between nearby populations. Our study demonstrated that the haplotype sharing pattern among East Asian Cerris oaks reflected the imprints of both shared ancestral polymorphism and introgression. This pattern was also associated with the relatively stable climates and complex landscapes in East Asia, which not only allowed the long‐term persistence of ancestral lineages but also connected the survived populations across refugia.

Toxicodendron succedaneum (L.) Kuntze is a deciduous and dioecious tree species in the family Anacardiaceae with important economic values. In this study, we sequenced and analyzed the complete chloroplast (cp) genome of T. succedaneum. The circular genome is 159,710 bp in size, and presents a quadripartite structure including two copies of inverted repeat (IR) regions of 26,524 bp, one large single-copy (LSC) region of 87,622 bp, and one small single-copy (SSC) region of 19,040 bp. It encodes a total of 113 unique genes, including 80 protein-coding genes, 29 tRNA genes, and four rRNA genes. Phylogenetic analysis based on 16 cp genome sequences revealed that the genus Toxicodendron is closely related to Pistacia and Rhus, and T. succedaneum was most closely related to T. vernicifluum.

Quercus ciliaris C.C.Huang & Y.T.Chang is one of the dominant tree species in the subtropical evergreen broad-leaved forests of China. In this study, we sequenced and analyzed the complete chloroplast (cp) genome of the species. The circular genome is 160,842 bp in size, consisting of two copies of inverted repeat (IR) regions of 25,823 bp, one large single-copy (LSC) region of 90,294 bp, and one small singlecopy (SSC) region of 18,902 bp. It encodes a total of 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis based on cp genome sequences of 35 Fagaceae species indicated that Q. ciliaris was among the members of section Cyclobalanopsis, and was most closely related to Q. myrsinifolia.