Traditional classification based on morphological characters suggests that the genus Ostericum is closely related to Angelica, but molecular phylogenetic studies suggest that the genus Ostericum is related to Pternopetalum rather than Angelica. In this study, the plastomes of nine Ostericum species and five Angelica species were used to conduct bioinformatic and comparative analyses. The plastomes of Ostericum and Angelica exhibited significant differences in genome size, gene numbers, IR junctions, nucleotide diversity, divergent regions, and the repeat units of SSR types. In contrast, Ostericum is more similar to Pternopetalum rather than Angelica in comparative genomics analyses. In total, 80 protein-coding genes from 97 complete plastomes and 112 ITS sequences were used to reconstruct phylogenetic trees. Phylogenies showed that Angelica was mainly located in Selineae tribe while Ostericum was a sister to Pternopetalum and occurred in the Acronema clade. However, morphological analysis was inconsistent with molecular phylogenetic analysis: Angelica and Ostericum have similar fruit morphological characteristics while the fruits of Ostericum are quite different from the genus Pternopetalum. The phylogenetic relationship between Angelica and Ostericum is consistent with the results of plastome comparisons but discordant with morphological characters. The cause of this phenomenon may be convergent morphology and incomplete lineage sorting (ILS).

Melanosciadium is considered a monotypic genus and is also endemic to the southwest of China. No detailed phylogenetic studies or plastid genomes have been identified in Melanosciadium. In this study, the plastid genome sequence and nrDNA sequence were used for the phylogenetic analysis of Melanosciadium and its related groups. Angelica tsinlingensis was previously considered a synonym of Hansenia forbesii. Similarly, Ligusticum angelicifolium was previously thought to be the genus Angelica or Ligusticopsis. Through field observations and morphological evidence, we believe that the two species are more similar to M. pimpinelloideum in leaves, umbel rays, and fruits. Meanwhile, we found a new species from Anhui Province (eastern China) that is similar to M. pimpinelloideum and have named it M. Jinzhaiensis. We sequenced and assembled the complete plastid genomes of these species and another three Angelica species. The genome comparison results show that M. pimpinelloideum, A. tsinlingensis, Ligusticum angelicifolium, and M. jinzhaiensis have similarities to each other in the plastid genome size, gene number, and length of the LSC and IR regions; the plastid genomes of these species are distinct from those of the Angelica species. In addition, we reconstruct the phylogenetic relationships using both plastid genome sequences and nrDNA sequences. The phylogenetic analysis revealed that A. tsinlingensis, M. pimpinelloideum, L. angelicifolium, and M. jinzhaiensis are closely related to each other and form a monophyletic group with strong support within the Selineae clade. Consequently, A. tsinlingensis and L. angelicifolium should be classified as members of the genus Melanosciadium, and suitable taxonomical treatments have been proposed. Meanwhile, a comprehensive description of the new species, M. jinzhaiensis, is presented, encompassing its habitat environment and detailed morphological traits.

Hansenia trifoliolata Q.P.Jiang & X.J.He (Apiaceae), is described as new from Shaanxi Province, northwest China. The mericarp features of H. trifoliolata resemble H. himalayensis and H. phaea and molecular phylogenetic analyses (combining ITS and plastid genomes data) suggest that H. trifoliolata is closely related to the group formed by H. oviformis and H. forbesii. The new species H. trifoliolata has unique 3-foliolate leaves and differ from other Hansenia species in its leaves, umbel numbers and size. A comprehensive description of H. trifoliolata is provided, including habitat environment and detailed morphological traits.

The study reanalyzed the morphology (especially fruits) and phylogeny (based on nrITS and plastid DNA rpl16 and rps16 intron sequences) of S. filicinum and its related species aiming to resolve taxonomic uncertainties. The results showed that Meeboldia achilleifolia, M. delavayi, M. linearis, M. microloba and S. filicinum constitute a well-supported monophyly in nrITS and plastid DNA trees. We found that S. filicinum is distinct from other Sinocarum species including S. vaginatum, S. cruciatum and the type S. coloratum in all trees. Concern morphology, S. filicinum is more similar to Meeboldia species, rather than S. coloratum in plant height, fruit size, number of vallecular vittae and commissural vittae. The authors propose that S. filicinum be transferred to Meeboldia and be renamed as Meeboldia filicina (H.Wolff) W.Gou, Y.P.Xiao & X.J.He.

Background Subtribe Angelicinae is a large and taxonomically complex group of Apiaceae, encompassing Angelica, Archangelica, Coelopleurum, Conioselinum, Czernaevia, Glehnia, Levisticum and Ostericum that are distributed in the Northern Hemisphere, and whether this taxa is natural is debatable, especially between Angelica and Ostericum. To determine genommic evolution and phylogenetic relationships between Angelica, Ostericum, and related species, we newly assembled the complete plastid genome sequences of eight subtribe Angelicinae species and Melanosciadium pimpinelloideum using next-generation sequencing technology. Results The nine plastid genomes we sequenced were conserved, and their size ranged from 146765 bp to 164329 bp, showing the typical quadripartite circular structure with an overall GC content of 37.5–37.8%. IR boundary analyses showed that the genes in the LSC region transfer into the IR regions and the SSC region was relatively stable. Codon usage patterns were similar among these species and we identified 66–86 SSRs, with the most abundant SSR being mononucleotide. The Pi analyses showed that petA-psbJ(0.02778), atpI-atpH(0.17333) and petA-psbJ(0.04726) intergenic regions had the highest Pi values in Angelica, Ostericum, and ten species, respectively. Conclusions Ostericum exhibited significant differences in size of genomes, content of genes and tRNAs, GC content, some type of SSRs, and IR boundaries to Angelica, and phylogenetic analyses found the relatedness between Angelica and Ostericum is more distant in protein-coding genes of the plastid genomes trees and nrITS trees.