Chapters authored
Hybridogenic Activity of Invasive Species of Asteraceae
We studied taxa from genus Bidens, Solidago, and Erigeron, sect. Conyza (Asteraceae). By analyzing the nucleotide sequences of the internal transcribed spacer (ITS1)-ITS2 site, the hybrid origin of the Bidens × decipiens, previously attributed to the North American alien species B. connata, was confirmed. The analysis of trnL-trnF sequences showed that the native B. cernua is the maternal species and the invasive B. frondosa is the paternal species in all probabilities. Diagnostic morphological features of the three Solidago taxa growing together in the vicinity of Pskov have been studied: a native S. virgaurea, an invasive species of North American origin S. canadensis, and their hybrid S. × niederederi. S. × niederederi has an intermediate position between S. virgaurea and S. canadensis. The hybrid origin of S. × niederederi is proven by molecular analysis of nuclear DNA nucleotide sequences (ITS1-ITS2 site). It is not yet possible to unambiguously answer the question which parent species is maternal and which is paternal. We also studied invasive species of the genus Erigeron sect. Conyza in the Mediterranean. Occasionally occurring in Southern Europe, individuals of E. canadensis × E. sumatrensis with intermediate morphological features, described as “Conyza × rouyana,” are likely unstable and soon “absorbed” by the parent species E. sumatrensis. Contrary to the hypothesis by C. Elton explaining the success of plant invasion in a new homeland by strengthening hybridization processes in the secondary distribution range.
Part of the book: Invasive Species