The evolutionary history of Clematis section Tubulosae, an East Asian endemic lineage, has not been comprehensively studied. In this study, we reconstruct the phylogeny of this section with a complete sampling using a phylogenomic approach. The genome skimming method was applied to obtain the complete plastome sequence, the nuclear ribosomal DNA (nrDNA), and the nuclear SNPs data for phylogenetic reconstruction. Using a Bayesian molecular clock approach and ancestral range reconstruction, we reconstruct biogeographical history and discuss the biotic and abiotic factors that may have shaped the distribution patterns of the section. Both nuclear datasets better resolved the phylogeny of the sect. Tubulosae than the plastome sequence. Sect. Tubulosae was resolved as a monophyletic group sister to a clade mainly containing species from the sect. Clematis and sect. Aspidanthera. Within sect. Tubulosae, two major clades were resolved by both nuclear datasets. Two continental taxa, C. heracleifolia and C. tubulosa var. ichangensis, formed one clade. One continental taxon, C. tubulosa, and all the other species from Taiwan island, the Korean peninsula, and the Japanese archipelago formed the other clade. Molecular dating results showed that sect. Tubulosae diverged from its sister clade in the Pliocene, and all the current species diversified during the Pleistocene. Our biogeographical reconstruction suggested that sect. Tubulosae evolved and began species diversification, most likely in mainland China, then dispersed to the Korean peninsula, and then expanded its range through the Japanese archipelago to Taiwan island. Island species diversity may arise through allopatric speciation by vicariance events following the range fragmentation triggered by the climatic oscillation and sea level change during the Pleistocene epoch. Our results highlight the importance of climatic oscillation during the Pleistocene to the spatial-temporal diversification patterns of the sect. Tubulosae.

The tribe Ranunculeae, Ranunculaceae, comprising 19 genera widely distributed all over the world. Although a large number of Sanger sequencing-based molecular phylogenetic studies have been published, very few studies have been performed on using genomic data to infer phylogenetic relationships within Ranunculeae. In this study, the complete plastid genomes of nine species (eleven samples) from Ceratocephala, Halerpestes, and Ranunculus were de novo assembled using a next-generation sequencing method. Previously published plastomes of Oxygraphis and other related genera of the family were downloaded from GenBank for comparative analysis. The complete plastome of each Ranunculeae species has 112 genes in total, including 78 protein-coding genes, 30 transfer RNA genes, and four ribosomal RNA genes. The plastome structure of Ranunculeae samples is conserved in gene order and arrangement. There are no inverted repeat (IR) region expansions and only one IR contraction was found in the tested samples. This study also compared plastome sequences across all the samples in gene collinearity, codon usage, RNA editing sites, nucleotide variability, simple sequence repeats, and positive selection sites. Phylogeny of the available Ranunculeae species was inferred by the plastome data using maximum-likelihood and Bayesian inference methods, and data partitioning strategies were tested. The phylogenetic relationships were better resolved compared to previous studies based on Sanger sequencing methods, showing the potential value of the plastome data in inferring the phylogeny of the tribe.

Plant taxonomic knowledge contains a long tail of infrequently encountered names, diagnostic characters, and nomenclatural decisions, yet model reliability across this distribution remains unclear. We developed the Chinese-language PTTB-600, comprising 200 general, 300 ordinary specialized, and 100 long-tail fill-in questions, and evaluated 31 large language models (LLMs) or run modes under closed-book conditions without retrieval augmentation. The first author drafted the question bank and answer key; three coauthors with doctorates in plant taxonomy reviewed them independently. All models scored at least 197/200 on general questions, and 21 achieved full marks. The six highest-scoring models answered 291–297/300 ordinary specialized questions (97.0–99.0%) but achieved 63.0–90.0% accuracy on long-tail fill-in questions. Gemini 3.1 Pro Preview ranked first at 587/600; ranks two through six formed a closely spaced cluster with no significant adjacent differences after Holm correction. Across 11 within-family comparisons, thinking-mode runs yielded 20–65 additional correct answers, chiefly on specialized and fill-in tasks. Factual errors were uncommon in routine undergraduate content and concentrated in the generation of rare genus names, fine diagnostic distinctions, and alternative nomenclatural treatments. Top-performing LLMs can provide reliable support for routine teaching under instructor oversight, whereas long-tail identifications and nomenclatural decisions require verification against authoritative sources.