Taxonomic revision of Delphinium (Ranunculaceae) in the south-east of European Russia

Morphological and phylogenetic (nrITS barcode) analyses are conducted to clarify the taxonomic status of 10 Delphinium species (D. cuneatum, D. dyctiocarpum, D. duhmbergii, D. elatum, D. litwinowii, D. pubiflorum, D. puniceum, D. sergii, D. subcuneatum, D. uralense) grown in the south-east of European Russia. The morphometric analysis is carried out with 22 quantitative and 32 qualitative parameters. Based on all parameters, the PCoA supports the differentiation of D. puniceum, D. sergii, D. uralense and D. pubiflorum whereas other studied taxa remain undistinguished. Furthermore, the Random forest analysis and the MrBayes phylogenetic analysis of ITS sequences confirm the species independence of D. puniceum belonging to the Diedropetala section and D. elatum, D. uralense, D. dyctiocarpum and D. pubiflorum belonging to the Delphinastrum section. Finally, recursive partitioning is performed to develop the dichotomous key which can be used to differentiate between Delphinium species in th...