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.

Two new species of Polyalthiopsis (Annonaceae), P. nigra Y.H. Tan & Bin Yang from Guangxi and Yunnan Provinces and P. xui Y.H. Tan & Bin Yang from Yunnan Province, are described and illustrated. P. nigra is morphologically similar to P. chinensis in having narrowly elliptic-oblong, lemon to yellowish green petals, but differs by having obovoid monocarps, a higher number of leaf secondary veins, leaf blades usually widest above the middle, and a lower ratio of leaf blade length to width. P. xui is morphologically similar to P. floribunda in having axillary inflorescences, 1–3(–4) flowers, elliptic leaves, and elliptic-ovate petals, but differs in the numbers of carpels per flower and ovules per carpel. The molecular phylogenetic analysis using five plastid markers confirm that the two new species belong to the genus Polyalthiopsis and show clear interspecific divergences between P. nigra and P. xui and between them and other species in the genus. Detailed descriptions, colored photographs, and habitat and distribution data for the two new species are provided. In addition, the fruit morphology of P. chinensis is described for the first time, based on living collections. Geographical distributions and a diagnostic key for all Polyalthiopsis species are also presented.

Climate is a key driver shaping the distribution pattern of organisms. Cenozoic climate change has led to extensive biota turnover. Untangling the distribution dynamics of a representative lineage of flora can provide deep insights into biodiversity conservation. Diplopanax is a notable relict lineage of the Tertiary mastixioid flora with abundant fossils in the Northern Hemisphere. Diplopanax stachyanthus Hand.-Mazz. is a representative relic lineage of the mastixioid flora, which was once widespread in the Northern Hemisphere of the early Tertiary period, but with only endemic distribution in the (sub)tropical humid forests of East Asia. It offers a unique chance to understand how climatic drivers shape the Boreotropical flora. In this research, we investigated the distribution dynamics of D. stachyanthus at the last glacial maximum (LGM), mid-Holocene (MH), current, and three periods of the future (2041–2060, 2061–2080, and 2081–2100) at four shared socio-economic emissions scenarios pathways. Our results indicated that the Precipitation of the Wettest Quarter (32.6%), the Precipitation of the Driest Quarter (21.2%), and the Precipitation of the Coldest Quarter (17.3%) are the key factors affecting its distribution. The current high suitable distribution areas are primarily in southern China and northern Indo-China. The enforced winter monsoon seasons in East Asia since the late Pliocene period are the key climatic drivers reducing its once widespread distribution in the Northern Hemisphere. Under future scenarios, centroid transfer analysis suggests that its distribution center will shift southwestward, but the potentially suitable habitats in the coastal regions of southern China and northern Indo-China will be lost. These coastal populations should be prioritized for ex situ conservation. Expanding the nature reserve within its long-term stable distribution range in southwest China is an effective strategy for the in situ conservation of the ancient mastixioid flora.

The genus Salsola ( Amaranthaceae ) comprises approximately 130 species distributed across Asia, Africa, and Europe, many of which possess important medicinal, horticultural, and ecological significance. Known for its remarkable ecological plasticity, Salsola species thrive in arid, semi-arid, and saline-alkaline environments, serving as key components of desert plant communities. However, extreme environmental pressures have driven convergent evolution, resulting in morphological similarities that obscure phylogenetic relationships. While this structural complexity offers significant horticultural potential, the genus’s evolutionary branching remains poorly understood. In this study, we analyzed complete plastomes of 14 well-defined Salsola species to resolve these primary phylogenetic lineages. The results show that Salsola plastomes range from 149,653 to 152,969 bp in length and harbor 130 annotated genes. These sequences exhibit high synteny, with inverted repeat (IR) regions showing greater conservation than single-copy regions. Our phylogenetic analysis resolved the genus into two basal clades. One clade predominantly consists of annual herbs (e.g., S. brachiata , S. collina , and S. ruthenica ), while the other includes the shrub S. arbuscula and semi-shrubs such as S. orientalis , S. passerina , and S. abrotanoides . From the perspective of complete plastome data, our results appear to support Salsola as a well-supported monophyletic lineage. Nevertheless, this inference should be treated with caution because it is based solely on plastome evidence; broader taxon sampling and nuclear genomic data will be needed to further test this conclusion. By providing complete plastome resources for representative Salsola species, this study offers a genomic foundation for future taxonomic clarification, species identification, germplasm conservation, medicinal and horticultural utilization of the genus.

A new species, namely Monolophus unifolius, from Northern Myanmar is described and illustrated. Its systematic placement was confirmed through molecular phylogenetic analyses using nuclear ribosomal ITS sequences. Morphologically, this new species is notably distinct from other Monolophus species in having only one leaf blade per leafy shoot and white labellum tinged with yellow spot at the throat. A key to the Monolophus species currently recorded in Myanmar is also provided.