A phenetic study on Aconitum ×hebegynum DC. (Ranunculaceae) in the Eastern Carpathians

The aim of the study was to re-evaluate the taxon limits of the putative hybrid A. ×hebegynum (A. degenii × A. variegatum). The nothospecies was described on the specimen originated from a region of the Swiss Alps. Its occurrence in the Eastern Carpathians is controversial since one of the putative parents A. variegatum is extremely rare there. A phenetic analysis using quantitative and qualitative floral and leaf morphology characters in 159 herbarium specimens (OTUs) of Aconitum sect. Aconitum ser. Variegata (A. variegatum), ser. Toxicum (A. degenii and A. lasiocarpum and putative hybrid A. ×gayeri) and nser. Toxigata (A. ×hebegynum) from the Eastern Carpathians was carried out. The analyses included Detrended Correspondence Analysis (DCA), Canonical Correspondence Analysis (CCA), Monte Carlo permutation tests, and description statistics. This confirmed the intermediate position of the nothospecies in a morphospace delimited by the putative parents. One of the morphotypes showed introgression towards species of the ser. Toxicum. The other, relatively rare morphotype , was similar to that occurring in the Alps. The Helmet Index of the nothotaxon was exactly between the values found for the putative parents. The findings did not directly point to the existence of the genetic hybrid in the Eastern Carpathians; more molecular DNA and cytogenetic data are needed. They pointed to the existence of distinct morphotypes which, in the case of the rejection of the hypothesis of nothotaxon existence in the region, should be circumscribed in a low-rank taxon within A. degenii.