Phylogenetic placement of Triaenophora (formerly Scrophulariaceae) with some implications for the phylogeny of Lamiales

Phylogenetic placement of Triaenophora together with Rehmannia were explored with DNA sequence data from five regions (rbcL, ndhF, rps16, trnL-F, nr ITS) in two combined data matrices. One (rbcL, ndhF, rps16) represented a wide sampling across most families of Lamiales. The other data matrix represented two DNA regions partly unalignable across Lamiales (trnL-F, nr ITS) plus rps16, which proved to be variable enough to give resolution at a smaller taxonomic level in Lamiales. Triaenophora rupestris and Rehmannia are sister taxa, composing a strongly supported clade, which is sister to all representative genera of Orobanchaceae. Furthermore, Paulowniaceae and Phrymaceae are next to Orobanchaceae and Triaenophora-Rehmannia clade. All of the above taxa are only distantly related to Scrophulariaceae and/or Plantaginaceae (sensu APG II). Mazus and Lancea would be excluded from Phrymaceae. The resulting phylogeny is in agreement with other data such as phytochemistry and provides a framework for further investigation of character evolution in Lamiales.