Phylogenetics of Mazaceae (Lamiales), with special reference to intrageneric relationships within Mazus

Abstract

Mazaceae, a recently proposed family in the Lamiales, contains three genera; Mazus, Lancea and Dodartia, yet the systematic position and the circumscription of the family have not been fully confirmed. This paper reports on an expanded analysis of the family that included most species of all three genera using five chloroplast DNA regions (matK, psbA-trnH intergenic spacer, rbcL, rps16, trnL-F intergenic spacer) and ITS of nrDNA to determine the phylogenetic placement of Mazaceae as well as the intrageneric relationships within the relatively large genus Mazus. The results support the recognition of the three genera (Mazus, Lancea, Dodartia), confirm the well-supported monophyly of Mazaceae and show Lancea and Dodartia to be clustered together and sister to Mazus. The phylogenetic relationships within the Lamiales is highly congruent with previous molecular studies, with Mazaceae sister to a clade comprising Orobanchaceae, Phrymaceae and Paulowniaceae. Together they are sister to the rest of the families in the order. In Mazus, two major lineages were recognized, corresponding to the distribution ranges in Australia and Asia. Previous sectional treatments of Mazus are discussed in light of our molecular phylogenetic results. This study confirms the systematic position of Mazaceae within the Lamiales. The intrageneric relationships revealed in Mazus will provide evidence for further taxonomic studies of the genus.