Incongruence in Veroniceae (Plantaginaceae): evidence from two plastid and a nuclear ribosomal DNA region

Nucleotide data from nuclear ribosomal and plastid DNA did not agree on all relationships within Veroniceae (Plantaginaceae) in previous analyses. We present here additional data from a second plastid DNA marker, the rps16 intron, and evaluate incongruence between the ribosomal and plastid DNA matrices. Based on these evaluations and analysis of secondary structure in ITS, we conclude that there is a biological cause for incongruence among the genera of Veroniceae. The sequence data imply a history of hybridization and polyploidization, in which ancestors of Wulfeniopsis and Veronica + Paederota gave rise to Picrorhiza and ancestors of Wulfeniopsis and Wulfenia gave rise to Veronicastrum.