A Phylogeny of Toadflaxes (Linaria Mill.) Based on Nuclear Internal Transcribed Spacer Sequences: Systematic and Evolutionary Consequences

Premise of research. Toadflaxes (Linaria Mill., ∼150 spp. from the Palearctic region) constitute the largest genus of the snapdragon lineage (tribe Antirrhineae). Here we provide the first extensive phylogenetic testing of systematic and evolutionary hypotheses about toadflaxes.Methodology. Internal transcribed spacer (ITS) sequences were obtained for 94 species representing all sections of Linaria recognized by recent taxonomic treatments, as well as three species of the morphologically related American genus Nuttallanthus. In addition, 71 sequences representing the remaining 26 genera of Antirrhineae were gathered to test the monophyly of toadflaxes. Phylogenetic analyses were conducted using Bayesian inference and maximum likelihood. Evaluation of alternative topologies was assessed by means of Bayes factor analyses.Pivotal results. Linaria and Nuttallanthus constituted a monophyletic group within the Antirrhineae. Linaria was recovered as a paraphyletic group with Nuttallanthus nested within it. Six m...