Molecular phylogenetics of Pimpinella and allied genera (Apiaceae), with emphasis on Chinese native species, inferred from nrDNA ITS and cpDNA intron sequence data

The genus Pimpinella comprises about 150 species, making it among the largest genera in Apiaceae subfamily Apioideae. It is also a widespread and taxonomically complex group. Previous molecular phylogenetic studies of Pimpinella have focused primarily on its Turkish, African and Malagasy congeners, while resolution of relationships among the approximately 44 species of Pimpinella native to China remains largely obscure, as is the proper circumscription of the genus. In this study, phylogenetic analyses of nrDNA ITS and cpDNA rps16 intron and rpl16 intron sequences were used to assess relationships among Pimpinella species and their closest allies, with emphasis on those species of Pimpinella native to China. We included 122 accessions in the ITS analysis, representing 62 species of Pimpinella of which 26 are native to China, and 54 accessions in the cpDNA and combined molecular analyses, the latter representing 20 species of Pimpinella native to China. The phylogenies inferred from cpDNA intron sequences are highly consistent with those inferred using ITS data. In all analyses, Pimpinella is resolved as non-monophyletic, yet the monophyly of a Pimpinella'core group' in tribe Pimpinelleae is strongly supported. Most Chinese native Pimpinella species fall within this core group; the other Chinese species examined appear in four other tribes within the subfamily. For all Chinese taxa, we consider relevant cytological, morphological, palynological, or phytogeographical data supporting their phylogenetic placements. The new combination Spuriopimpinella arguta (Diels) X. J. He & Z. X. Wang is proposed.