Aristolochiaceae, comprising about 600 species, is a unique plant family containing aristolochic acids (AAs). In this study, we sequenced seven species of Aristolochia, and retrieved eleven chloroplast (cp) genomes published for comparative genomics analysis and phylogenetic constructions. The results show that the cp genomes had a typical quadripartite structure with conserved genome arrangement and moderate divergence. The cp genomes range from 159,308 bp to 160,520 bp in length and have a similar GC content of 38.5%–38.9%. A total number of 113 genes were identified, including 79 protein-coding genes, 30 tRNAs and four rRNAs. Although genomic structure and size were highly conserved, the IR-SC boundary regions were variable between these seven cp genomes. The trnH-GUG genes, are one of major differences between the plastomes of the two subgenera Siphisia and Aristolochia. We analyzed the features of nucleotide substitutions, distribution of repeat sequences and simple sequences repeats (SSRs), positive selections in the cp genomes, and identified 16 hotspot regions for genomes divergence that could be utilized as potential markers for phylogeny reconstruction. Phylogenetic relationships of the family Aristolochiaceae inferred from the 18 cp genome sequences were consistent and robust, using maximum parsimony (MP), maximum likelihood (ML), and Bayesian analysis (BI) methods.

Hybridization and introgression have long obscured relationships within Adenophora and its relatives, complicating generic delimitation. Leveraging deep genome skimming (DGS) data, we generated a large dataset, including thousands of single-copy nuclear (SCN) genes and plastomes, to untangle this reticulate history. Specifically, 9.89 terabytes (TB) of DGS data from 165 samples—representing 48 species and 13 subspecies of Adenophora (out of ca. 72 species) plus 24 outgroup species—yielded 1506 SCN genes and 77 plastid coding sequences. Tree-like phylogenies inferred with both coalescent- and concatenation-based methods revealed pronounced gene tree heterogeneity. Subsequent analysis showed that incomplete lineage sorting contributed minimally to this discordance; instead, hybridization and introgression were the primary drivers of early diversification. Integrating phylogenomic, morphological, and geographic evidence, we propose a revised generic framework for this group. Adenophora is expanded to include Campanula delavayi and the Korean Peninsula endemic genus Hanabusaya. We also recommend reinstating Hyssaria as a distinct Central Asian genus and introducing two new genera, Boreoasia and Rosomala.

Aristolochia pseudoutriformis X.X.Zhu & J.S.Ma, sp. nov. and A. yangii X.X.Zhu & J.S.Ma, sp. nov., two new species from Yunnan, China, are described and illustrated here. The former is morphologically similar to A. utriformis and A. forrestiana and the latter is similar to A. cucurbitoides and A. forrestiana. According to Ma’s (1989a) classification, both new species belong to Aristolochia subgenus Siphisia on the basis of the 3-lobed gynostemium and oblong anthers that are adnate in pairs, opposite the gynostemium lobes. Meanwhile, the two new species are assessed as Vulnerable (VU D2) according to IUCN Red List criteria.

A self-supporting new species of Aristolochiaceae, Aristolochia zhuhaiensis Y.Fan Wang & Z.R.Guo, is described and illustrated from Zhuhai City, Guangdong Province, China. Morphologically, this species exhibits vegetative characters, including leaf blade shape and growth form, that are similar to Aristolochia thwaitesii Hook., the only other known taxon in Aristolochia subg. Siphisia in Asia that is non-twining and self-supporting, native to southern Guangdong, particularly the Hong Kong Special Administrative Region. However, A. zhuhaiensis can be readily distinguished from A. thwaitesii by its unique floral morphology. The new species features a campanulate to funnel-shaped calyx limb densely covered with porcelain-white granular pustules. In contrast, A. thwaitesii has an elongated, concave tubular calyx limb with an adaxial surface that transitions from purple to pale yellow or white towards the apex, densely covered with recurved fleshy prickles. Aristolochia zhuhaiensis is endemic to Zhuhai City and has not been observed elsewhere. Detailed illustrations, photographic plates, a distribution map, a digitized holotype voucher specimen, a comparative table, and an identification key are provided to facilitate the differentiation of A. zhuhaiensis from A. thwaitesii.